Questo lavoro è stato sostenuto dal Dipartimento di Ingegneria Biomedica presso la Case Western Reserve University di laboratorio sia attraverso fondi di start-up (J. Capadona), e la Medtronic Graduate Fellowship (K. Potter). Ulteriori finanziamenti in questa ricerca è stata sostenuta in parte dalla NSF concedere ECS-0621984 (C. Zorman), il Caso Alumni Association (C. Zorman), il Department of Veterans Affairs attraverso una recensione Merit Award (B7122R), così come l&#39;Advanced Platform Technology Center (C3819C).

1. Preparazione del campione <ol><li> Preparare pellicola PVAc-NC di spessore nel campo di 25-100 micron utilizzando una soluzione di colata e tecnica di compressione 10-12. </li><li> Aderire pellicola ad un wafer di silicio mediante riscaldamento su una piastra calda per due minuti a 70 ° C (sopra della temperatura di transizione vetrosa) promuovere intimo contatto tra il film e il wafer. Questo passaggio garantisce che il film preparato rimane piatto e fisso al wafer Si, necessario per i processi planari micromachining. </li><li> Motivo del film nelle geometrie di prova del campione di laser micromachining (VLS 3.50, VersaLASER). Impostare i 2 parametri micromachining laser direct-scrittura di CO al 1,0% di potenza (0,5 W), velocità 4,0% (56 mm / s), e 1.000 impulsi per pollice 13,16. </li><li> Campioni di pattern che saranno utilizzati per stabilire le condizioni ambientali (&quot;campioni Setup&quot;) in strutture a forma di osso di cane con dimensioni pad laterali 1,5 x 1,5 mm 2, e la trave laterale dimensioni 300 x 3.000 micron 2, con uno spessore corrispondente a quello della pellicola durante (Figura 2). </li><li> Reticolo i campioni per esperimenti ex vivo (&quot;campione protesi&quot;) nelle travi 300 micron x 6 mm, con uno spessore corrispondente a quello del film. </li><li> Rilasciare con attenzione i campioni dal wafer utilizzando una lama di rasoio e pinzette. </li><li> Per la manipolazione del campione, preparare gli imprenditori acrilico su misura lavorati destinati a servire come parte del sistema di presa nel tester microtensile. Marcature incise con il laser mostrano la linea centrale del titolare e 1,5 mm dalla fine. Mettere una piccola quantità di cianoacrilato adesivo a base di gel sulla linea centrale del supporto acrilico e accuratamente aderire una lunghezza di 1,5 mm del campione dell&#39;impianto al titolare e sovrapporsi alla mezzeria marcata (Figura 3). Ogni campione impianto necessita di un supporto acrilico. Fare attenzione a garantire che il gel adesivo rimane solo lungo la lunghezza di 1,5 mm PVAc-NC essendo aderito alla acrtitolare ylic. Altrimenti, il gel adesivo può interferire con il comportamento meccanico del campione. </li><li> Rimuovere l&#39;umidità da tutti i campioni mettendoli in un essiccatore per almeno 24 ore. </li><li> Misurare la lunghezza, la larghezza e dimensioni di spessore dei campioni utilizzando un microscopio ottico. </li></ol> 2. Stabilire Condizioni ambientali <ol><li> Caricare un campione di impostazione secco nel tester microtensile (vedi Figura 4), ​​prima di serraggio tra i morsetti mobili, quindi tra le impugnature fisse. </li><li> Montare una spazzola d&#39;aria con un serbatoio pieno d&#39;acqua in una posizione fissa, con l&#39;ugello rivolto verso il campione microtensile. Collegare la spazzola di aria di un compressore d&#39;aria attraverso tubi di plastica. Con l&#39;ugello aria pennello completamente chiuso, accendere il compressore d&#39;aria. </li><li> Iniziare procedura di test microtensile ciclica, alternando sforzo a trazione (ceppo positivo) e tensione di pressione (ceppo negativo) applicata a tegli campione, rimanendo all&#39;interno della regione elastica lineare del grafico tensione-deformazione. Per PVAc-NC, la deformazione applicata è limitata a meno del 2%. Nel tester microtensile personalizzato utilizzato in questi esperimenti, la velocità di deformazione è stata controllata mentre la forza necessaria per raggiungere tale ceppo è stato misurato. In alternativa, un setup diverso potrebbe comportare il controllo della forza applicata durante la misurazione della tensione risultante. </li><li> Aumentare gradualmente il flusso dall&#39;ugello aria pennello, e monitorare la pendenza del grafico di sollecitazione-deformazione in funzione della quantità di flusso d&#39;aria dalla spazzola. La portata massima che non provoca una riduzione significativa (&gt; 10%) nel modulo di Young per un periodo di 60 sec è il livello che verrà utilizzato per gli esperimenti ex vivo. A questo punto, le condizioni di umidità che non bagnare un campione asciutto (e quindi contribuire alla riduzione di Young), e ridurrà campione essiccazione dopo essere stati esposti a fluidi biologici in vivo sono stati estazioni stabilite. </li><li> Misurare la temperatura in prossimità del campione. Un setup ideale dovrebbe includere una termocoppia con lettura digitale, ed essere eseguita mentre l&#39;aerografo è in funzione. Impostare l&#39;intensità e la distanza della sorgente di calore radiante tale che la temperatura del campione viene tenuto a 37 ° C, per adeguarsi alle condizioni fisiologiche. </li></ol> 3. Confronta controllo ambientale per il controllo non-Ambientale <ol><li> Campioni di impostazione Immergere per almeno 30 minuti in soluzione salina tampone fosfato. Dopo questo periodo di tempo, il campione è completamente saturo ed è stato ridotto al minimo modulo di Young ad una data temperatura. </li><li> Caricare rapidamente un campione nel tester microtensile e iniziare la prova microtensile ciclico, con la spazzola di aria fuori, mentre si asciuga il campione. Questo determina quanto rapidamente si asciuga il campione in condizioni non controllate. </li><li> Caricare un secondo campione di configurazione PBS-saturi nel tester microtensile, e iniziare la prova microtensile ciclicocon il pennello aria su. Questo determina quanto rapidamente si asciuga il campione in condizioni ambientali controllate. </li></ol> 4. Impianto sonda e Espianto <ol><li> Allegare campione impianto ad un morsetto micromanipolatore e ortogonale al tessuto corticale. </li><li> Prima dell&#39;inserimento, mantenere tessuto sufficientemente umido con soluzione salina per assicurare l&#39;omogeneità della meccanica dei tessuti. </li><li> Abbassare il campione di polimero nella corteccia utilizzando i comandi manuali micromanipolatore. Lasciare campione in tessuto corticale fino al momento dell&#39;impianto bersaglio, generalmente tra 1 e 30 min. Per evitare che il tessuto si secchi per i punti di tempo superiore a 5 minuti, tamponare leggermente il tessuto ogni 5 min usando un tampone di cotone imbevuta di soluzione salina. </li><li> Mentre la sonda è impiantato nella corteccia, preparare il tester microtensile per caricare il campione attualmente impiantato impostando il puntalino alla posizione zero-spostamento di 3,0 mm dal morsetto campione stazionaria. Inoltre, impostare l&#39;ugello aria pennelloall&#39;impostazione flusso e la fonte di calore radiante per determinare la corretta intensità nella Fase 2.4. </li><li> Al termine del tempo specificato dell&#39;impianto, innalzare la sonda fuori della corteccia utilizzando i comandi manuali micromanipolatore. Immediatamente e con attenzione, rimuovere il campione dal morsetto micromanipolatore e caricare nel tester microtensile, come descritto più dettagliatamente nella Fase 5.2. </li></ol> 5. Test microtrazione di campioni Implant <ol><li> Per risparmiare tempo dopo l&#39;espianto, assicurarsi che il tester microtensile è completamente pronto ad accettare il campione protesi prima dell&#39;impianto, come descritto al punto 4.4. </li><li> Subito dopo l&#39;espianto, caricare il campione tra i due set di pinze tester microtensile. Dal momento che il campione è montato un supporto acrilico progettato per servire come la metà superiore di una pinza, posizionare il gruppo campione impianto sul grip cellulare, parte del campione verso il basso. È importante assicurare che il campione è fissata in modo che ceppo è applied solo lungo la lunghezza della sonda per evitare di applicare coppia al campione durante la prova. Come tale, il campione deve essere montato al centro di ciascun morsetto, ed i morsetti devono essere a livello con rispetto all&#39;altro. </li><li> Regolare la posizione del campione tale che la distanza tra i morsetti è 3,0 mm, e l&#39;estremità della sonda viene inserita nella morsa fissa. Questo Lunghezza 3,0 mm tra i morsetti è il tratto utile per il campione, e sarà utilizzato in calcoli successivi per determinare la tensione sul campione. </li><li> Immediatamente dopo il fissaggio del campione fra entrambi i morsetti, e entro 2 min dell&#39;espianto dal tessuto neurale, attivare il motore nella direzione di trazione per allungare il campione ad una velocità costante (10 micron / sec utilizzati qui), e contemporaneamente misurare e registrare la allungamento del campione (utilizzando un indicatore di spostamento, Mitutoyu 543-561) e la forza associata (usando una cella di carico, Tecniche Trasduttore MDB-2.5) necessario per la tensione della campione. </li><li&gt; Arrestare il test microtensile caso di guasto meccanico del campione, o quando viene raggiunta la fine della gamma puntalino. Esportare i dati raccolti, ed eseguire l&#39;analisi dei dati. </li><li> Ripetere il test microtensile per ogni campione e / o di ogni insieme di condizioni (cioè il tempo di inserimento). </li></ol> 6. Analisi dei dati <ol><li> Convertire i dati grezzi allungamento a deformazione tecnica applicata al campione impianto dividendo la distanza di allungamento per il tratto utile iniziale, come descritto in Equazione 1, dove ε è la deformazione applicata, t è il tempo, d è lo spostamento misurato dal micrometro indicatore, e L 0 è il tratto utile iniziale del campione: <img src="/files/ftp_upload/50078/50078eq1.jpg" alt="Equazione 1" fo:src="/files/ftp_upload/50078/50078eq1highres.jpg"/> (1) </li><li> Convertire i dati grezzi forza per lo sforzo di ingegneria sul campione dividendo la forza (in Newton), dalla TRAarea della sezione trasversale nsverse, come descritto in Equazione 2: <img src="/files/ftp_upload/50078/50078eq2.jpg" alt="Equazione 2" fo:src="/files/ftp_upload/50078/50078eq2highres.jpg"/> (2) dove σ è la tensione sul campione, F è la forza misurata dalla cella di carico (in Newton), 0 w è la larghezza iniziale del campione, e 0 t è lo spessore iniziale del campione. </li><li> Tracciare lo stress (σ [t]) vs strain (ε [t]) curva per ogni campione utilizzando un programma per computer, come ad esempio Microsoft Excel. </li><li> Isolare la parte elastica lineare della trama e utilizzare gli strumenti di raccordo di curva a base di software per trovare la migliore curva di adattamento a questa parte. La pendenza della retta interpolante corrisponde al modulo di Young del campione. La porzione isolata del complotto dovrebbe includere almeno 10 punti di sforzo-deformazione, e dovrebbe essere preso dalla parte della trama, dove la pendenza è maggiore. </li><li> Per i test ciclici, il modulo di Young dovranno essere determinati per ogni ciclo. Questo può essere automatizzato o eseguita manualmente. </li><li> Per le prove cicliche, trama modulo di Young di ogni ciclo in funzione del tempo. Questo indica come cambia il modulo di misura con il tempo, il che è indicativo di quanto velocemente un campione di impostazione sta bagnando o essiccazione. </li><li> Per campioni implantari, ogni campione e momento dell&#39;impianto corrisponde ad un unico ciclo di prove cicliche. Misurare il modulo di Young secondo la procedura descritta sopra per ogni campione implantare. </li><li> Tracciare il modulo di Young in funzione del tempo dell&#39;impianto. A questo punto, i confronti possono essere fatti per investigazioni da banco, ecc </li></ol>

<ol>
	<li>Chen, P. J., Saati, S., Varma, R., Humayun, M. S., Tai, Y. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Wireless+intraocular+pressure+sensing+using+microfabricated+minimally+invasive+flexible-coiled+LC+sensor+implant.">Wireless intraocular pressure sensing using microfabricated minimally invasive flexible-coiled LC sensor implant.</a> Journal of Microelectromechanical Systems. 19, 721-734 (2010).</li><li>Ren, X., Zheng, N., Gao, Y., Chen, T., Lu, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Biodegradable+three-dimension+micro-device+delivering+5-fluorouracil+in+tumor+bearing+mice.">Biodegradable three-dimension micro-device delivering 5-fluorouracil in tumor bearing mice.</a> Drug Delivery. 19, 36-44 (2012).</li><li>Bai, Q. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Single-unit+neural+recording+with+active+microelectrode+arrays.">Single-unit neural recording with active microelectrode arrays.</a> IEEE Transactions on Biomedical Engineering. 48, 911 (2001).</li><li>Rousche, P. J., Pellinen, D. S., Pivin, D. P., Williams, J. C., Vetter, R. J., kirke, D. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Flexible+polyimide-based+intracortical+electrode+arrays+with+bioactive+capability.">Flexible polyimide-based intracortical electrode arrays with bioactive capability.</a> IEEE Transactions on Biomedical Engineering. 48, 361-371 (2001).</li><li>Hassler, C., Boretius, T., Stieglitz, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Polymers+for+neural+implants.">Polymers for neural implants.</a> Journal of Polymer Science Part B: Polymer Physics. 49, 18-33 (2011).</li><li>Mercanzini, A., Colin, P., Bensadoun, J. C., Bertsch, A., Renaud, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+Vivo+Electrical+Impedance+Spectroscopy+of+Tissue+Reaction+to+Microelectrode+Arrays.">In Vivo Electrical Impedance Spectroscopy of Tissue Reaction to Microelectrode Arrays.</a> IEEE Transactions on Biomedical Engineering. 56, 1909-1918 (2009).</li><li>Polikov, V. S., Tresco, P. A., Reichert, W. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Response+of+brain+tissue+to+chronically+implanted+neural+electrodes.">Response of brain tissue to chronically implanted neural electrodes.</a> Journal of Neuroscience Methods. 148, 1-18 (2005).</li><li>Subbaroyan, J., Kipke, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Engineering+in+Medicine+and+Biology+Society,+2006.">Engineering in Medicine and Biology Society, 2006.</a> , 3588-3591 (2006).</li><li>Harris, J., Capadona, J., Miller, R., Healy, B., Shanmuganathan, K., Rowan, S., Weder, C., Tyler, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mechanically+adaptive+intracortical+implants+improve+the+proximity+of+neuronal+cell+bodies.">Mechanically adaptive intracortical implants improve the proximity of neuronal cell bodies.</a> Journal of Neural Engineering. 8, 066011 (2011).</li><li>Capadona, J. R., Shanmuganathan, K., Tyler, D. J., Rowan, S. J., Weder, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stimuli-Responsive+Polymer+Nanocomposites+Inspired+by+the+Sea+Cucumber+Dermis.">Stimuli-Responsive Polymer Nanocomposites Inspired by the Sea Cucumber Dermis.</a> Science. 319, 1370-1374 (2008).</li><li>Shanmuganathan, K., Capadona, J. R., Rowan, S. J., Weder, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stimuli-Responsive+Mechanically+Adaptive+Polymer+Nanocomposites.">Stimuli-Responsive Mechanically Adaptive Polymer Nanocomposites.</a> ACS Applied Materials &amp; Interfaces. 2, 165-174 (2009).</li><li>Shanmuganathan, K., Capadona, J. R., Rowan, S. J., Weder, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bio-inspired+mechanically-adaptive+nanocomposites+derived+from+cotton+cellulose+whiskers.">Bio-inspired mechanically-adaptive nanocomposites derived from cotton cellulose whiskers.</a> Journal of Materials Chemistry. 20, 180 (2010).</li><li>Hess, A., Capadona, J., Shanmuganathan, K., Hsu, L., Rowan, S., Weder, C., Tyler, D., Zorman, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+a+stimuli-responsive+polymer+nanocomposite+toward+biologically+optimized,+MEMS-based+neural+probes.">Development of a stimuli-responsive polymer nanocomposite toward biologically optimized, MEMS-based neural probes.</a> Journal of Micromechanics and Microengineering. 21, 054009 (2011).</li><li>Capadona, J. R., Tyler, D. J., Zorman, C. A., Rowan, S. J., Weder, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mechanically+adaptive+nanocomposites+for+neural+interfacing.">Mechanically adaptive nanocomposites for neural interfacing.</a> Materials Research Society Bulletin. 37, 581-589 (2012).</li><li>Ophir, J., Cespedes, I., Garra, B., Ponnekanti, H., Huang, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Elastography:+ultrasonic+imaging+of+tissue+strain+and+elastic+modulus+in+vivo.">Elastography: ultrasonic imaging of tissue strain and elastic modulus in vivo.</a> European journal of ultrasound. 3, 49-70 (1996).</li><li>Hess, A., Shanmuganathan, K., Capadona, J., Hsu, L., Rowan, S., Weder, C., Tyler, D., Zorman, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Micro+Electro+Mechanical+Systems+(MEMS).">Micro Electro Mechanical Systems (MEMS).</a> , 453-456 (2011).</li><li>Harris, J. P., Hess, A. E., Rowan, S. J., Weder, C., Zorman, C. A., Tyler, D. J., Capadona, J. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vivo+deployment+of+mechanically+adaptive+nanocomposites+for+intracortical+microelectrodes.">In vivo deployment of mechanically adaptive nanocomposites for intracortical microelectrodes.</a> Journal of Neural Engineering. 8, 046010 (2011).</li><li>Shanmuganathan, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Bio-inspired Stimuli-responsive Mechanically Dynamic Nanocomposites. , (2010).</li><li>Rousche, P. J., Pellinen, D. S., Pivin, D. P., Williams, J. C., Vetter, R. J., Kipke, D. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Flexible+polyimide-based+intracortical+electrode+arrays+with+bioactive+capability.">Flexible polyimide-based intracortical electrode arrays with bioactive capability.</a> IEEE Transactions on Biomedical Engineering. 48, 361-371 (2001).</li><li>Norlin, P., Kindlundh, M., Mouroux, A., Yoshida, K., Hofmann, U. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+32-site+neural+recording+probe+fabricated+by+DRIE+of+SOI+substrates.">A 32-site neural recording probe fabricated by DRIE of SOI substrates.</a> Journal of Micromechanics and Microengineering. 12, 414 (2002).</li><li>Ward, M. P., Rajdev, P., Ellison, C., Irazoqui, P. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Toward+a+comparison+of+microelectrodes+for+acute+and+chronic+recordings.">Toward a comparison of microelectrodes for acute and chronic recordings.</a> Brain Research. 1282, 183-200 (2009).</li><li>Lin, J. M., Chang, P. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Novel+Remote+Health+Monitor+with+Replaceable+Non-Fragile+Bio-Probes+on+RFID+Tag.">A Novel Remote Health Monitor with Replaceable Non-Fragile Bio-Probes on RFID Tag.</a> Applied Mechanics and Materials. 145, 415-419 (2012).</li><li>Kunzelman, K. S., Cochran, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stress/strain+characteristics+of+porcine+mitral+valve+tissue:+parallel+versus+perpendicular+collagen+orientation.">Stress/strain characteristics of porcine mitral valve tissue: parallel versus perpendicular collagen orientation.</a> Journal of Cardiac Surgery. 7, 71-78 (1992).</li><li>Snedeker, J., Niederer, P., Schmidlin, F., Farshad, M., Demetropoulos, C., Lee, J., Yang, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Strain-rate+dependent+material+properties+of+the+porcine+and+human+kidney+capsule.">Strain-rate dependent material properties of the porcine and human kidney capsule.</a> Journal of Biomechanics. 38, 1011-1021 (2005).</li><li>Ahn, S., Kasi, R. M., Kim, S. C., Sharma, N., Zhou, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stimuli-responsive+polymer+gels.">Stimuli-responsive polymer gels.</a> Soft Matter. 4, 1151-1157 (2008).</li><li>Stuart, M. A. C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Emerging+applications+of+stimuli-responsive+polymer+materials.">Emerging applications of stimuli-responsive polymer materials.</a> Nature Materials. 9, 101-113 (2010).</li></ol>

Non abbiamo nulla da rivelare.

L&#39;avanzamento dei sistemi microelettromeccanici biomedici impiantabili (bioMEMS) per l&#39;interazione con i sistemi biologici è motivante lo sviluppo di nuovi materiali con proprietà altamente personalizzate. Alcuni di questi materiali sono progettati per esporre un cambiamento delle proprietà del materiale in risposta ad uno stimolo trovato ambiente fisiologico. Una classe di recente sviluppo di materiali risponde alla presenza di idrogeno liquidi bond-formatura (per esempio acqua) e temperature elevat...

<table border="1">
	<tbody>
		<tr>
			<td>Name of Reagent/Material</td>
			<td>Company</td>
			<td>Catalogue Number</td>
			<td>Comments</td>
		</tr>
		<tr>
			<td>Silicon wafer</td>
			<td>University Wafer</td>
			<td>&nbsp;</td>
			<td>Mechanical grade</td>
		</tr>
		<tr>
			<td>Extruded acrylic sheet</td>
			<td>Professional Plastics</td>
			<td>SACR 062EF</td>
			<td>Thickness 0.062"</td>
		</tr>
		<tr>
			<td>Razor blade</td>
			<td>McMaster-Carr</td>
			<td>3962A3</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Tweezers</td>
			<td>McMaster-Carr</td>
			<td>8384A47</td>
			<td>#5 tip</td>
		</tr>
		<tr>
			<td>Super Glue Gel</td>
			<td>Loctite</td>
			<td>130380</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Air Brush</td>
			<td>Snap-on Industrial</td>
			<td>BF175TA</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Air Compressor</td>
			<td>Paasche</td>
			<td>B002YKN8YO</td>
			<td>D500</td>
		</tr>
		<tr>
			<td>Thermocouple</td>
			<td>Omega</td>
			<td>HH12A</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Hot plate</td>
			<td>Cimarec</td>
			<td>SP131325Q</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>CO2 direct-write laser</td>
			<td>VersaLaser</td>
			<td>3.5</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Dessicator</td>
			<td>Fisher Scientific</td>
			<td>08-595</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Lamp</td>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
			<td>custom-built</td>
		</tr>
		<tr>
			<td>Microtensile tester</td>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
			<td>custom-built</td>
		</tr>
	</tbody>
</table>

environmentally-controlled microtensile testing of mechanically-adaptive polymer nanocomposites for ex vivo characterization

Microdevices impiantabili stanno guadagnando l&#39;attenzione significativa per diverse applicazioni biomediche 1-4. Tali dispositivi sono stati fatti da una serie di materiali, ognuno con i suoi vantaggi e le carenze 5,6. Più prominente, a causa delle dimensioni del dispositivo microscala, un elevato modulo è necessario per facilitare l&#39;impianto nel tessuto vivente. Viceversa, la rigidità del dispositivo dovrebbe corrispondere al tessuto circostante di minimizzare indotta deformazione locale 7-9. Pertanto, abbiamo recentemente sviluppato una nuova classe di materiali bio-ispirati per soddisfare queste esigenze, rispondendo agli stimoli ambientali con una modifica delle proprietà meccaniche 10-14. Specificamente, la nostra nanocomposito (acetato di vinile) basata poli (PVAc-NC) mostra una riduzione della rigidità quando esposti ad acqua e temperature elevate (ad esempio temperatura corporea). Sfortunatamente, esistono alcuni metodi per quantificare la rigidità dei materiali in vivo 15, e Mechtest meccanicaa esternamente all&#39;ambiente fisiologico richiede spesso grandi campioni appropriati per l&#39;impianto. Inoltre, i materiali stimoli-reattiva possono recuperare in fretta la loro rigidità iniziale dopo espianto. Pertanto, abbiamo sviluppato un metodo con cui le proprietà meccaniche del microcampioni impiantati possono essere misurati ex vivo, con condizioni fisiologiche simulate mantenuti utilizzando umidità e temperatura 13,16,17. A tal fine, un tester microtensile personalizzato è stato progettato per accogliere campioni microscala con 13,17 ampiamente variabili di moduli di Young (gamma da 10 MPa a 5 GPa). Come nostri interessi sono nella domanda di PVAc-NC come substrato sonda neurale biologicamente adattabile, uno strumento capace di caratterizzazione meccanica dei campioni alla microscala era necessario. Questo strumento è stato adattato per fornire umidità e controllo della temperatura, che minimizzata campione di essiccazione e raffreddamento 17. Come risultato, il meccanicoaL caratteristiche del campione espiantato strettamente riflettono quelle del campione appena prima espianto. L&#39;obiettivo generale di questo metodo è quello di valutare quantitativamente le proprietà meccaniche in vivo, in particolare il modulo di Young, di materiali di stimolo-risposta, meccanicamente-adattativa a base polimerica. Questo si ottiene prima stabilito le condizioni ambientali che minimizzeranno un cambiamento nel campione proprietà meccaniche dopo espianto senza contribuire ad una riduzione della rigidezza indipendente da quella risultante da impianto. I campioni vengono poi preparati per l&#39;impianto, la gestione e la prova (Figura 1A). Ogni campione viene impiantato nella corteccia cerebrale di ratto, che è rappresentato qui come un cervello di ratto espiantato, per una durata specificata (Figura 1B). A questo punto, il campione viene espiantato ed immediatamente caricato nel tester microtensile, e poi sottoposto a test di trazione (Figura1C). Di analisi dei dati permette di comprendere il comportamento meccanico di questi materiali innovativi nell&#39;ambiente della corteccia cerebrale.

Le proprietà meccaniche di quasi tutti i materiali polimerici, compreso il nostro PVAc-NC, dipendono esposizione a condizioni ambientali. Più in particolare, questi includono l&#39;esposizione al calore e all&#39;umidità. Quando un materiale viene plastificato dovuto alla captazione di umidità o subisce una transizione termica, visualizza una riduzione del modulo di Young. Nel preparare l&#39;umidità e temperatura controllata per ex campione caratterizzazione meccanica in vivo, è importante garan...

Watch this Scientific Journal Video about Environmentally-controlled Microtensile Testing of Mechanically-adaptive Polymer Nanocomposites for ex vivo Characterization at JoVE.com

Environmentally-controlled Microtensile Testing of Mechanically-adaptive Polymer Nanocomposites for ex vivo Characterization

Un metodo è discusso con cui la<em&gt; In vivo</em&gt; Comportamento meccanico di materiali stimoli-responsive viene monitorata in funzione del tempo. I campioni sono testati<em&gt; Ex vivo</em&gt; Usando un tester microtensile con controlli ambientali per simulare l&#39;ambiente fisiologico. Questo lavoro promuove ulteriormente la comprensione del<em&gt; In vivo</em&gt; Comportamento del nostro materiale.

Test microtrazione Environmentally-controllato di meccanica-adattivi nanocompositi polimerici per<em&gt; Ex vivo</em&gt; Caratterizzazione

Implantable microdevices are gaining significant attention for several biomedical applications1-4. Such devices have been made from a range of materials, ...

environmentally-controlled-microtensile-testing-mechanically-adaptive

Research

JoVE Journal

Bioengineering

Environmentally-controlled Microtensile Testing of Mechanically-adaptive Polymer Nanocomposites for ex vivo Characterization

10.1K Views.  Louis Stokes Cleveland Department of Veterans Affairs Medical Center. Un metodo è discusso con cui la In vivo Comportamento meccanico di materiali stimoli-responsive viene monitorata in funzione del tempo. I campioni sono testati Ex vivo Usando un tester microtensile con controlli ambientali per simulare l'ambiente fisiologico. Questo lavoro promuove ulteriormente la comprensione del In vivo Comportamento del nostro materiale.

Video: Environmentally-controlled Microtensile Testing of Mechanically-adaptive Polymer Nanocomposites for ex vivo Characterization

Design of a Cyclic Pressure Bioreactor for the Ex Vivo Study of Aortic Heart Valves

The aortic valve, located between the left ventricle and the aorta, allows for unidirectional blood flow, preventing backflow into the ventricle. Aortic valve leaflets are composed of interstitial cells suspended within an extracellular matrix (ECM) and are lined with an endothelial cell monolayer. The valve withstands a harsh, dynamic environment and is constantly exposed to shear, flexion, tension, and compression. Research has shown calcific lesions in diseased valves occur in areas of high mechanical stress as a result of endothelial disruption or interstitial matrix damage1-3. Hence, it is not surprising that epidemiological studies have shown high blood pressure to be a leading risk factor in the onset of aortic valve disease4. 
The only treatment option currently available for valve disease is surgical replacement of the diseased valve with a bioprosthetic or mechanical valve5. Improved understanding of valve biology in response to physical stresses would help elucidate the mechanisms of valve pathogenesis. In turn, this could help in the development of non-invasive therapies such as pharmaceutical intervention or prevention. Several bioreactors have been previously developed to study the mechanobiology of native or engineered heart valves6-9. Pulsatile bioreactors have also been developed to study a range of tissues including cartilage10, bone11 and bladder12. The aim of this work was to develop a cyclic pressure system that could be used to elucidate the biological response of aortic valve leaflets to increased pressure loads. 
The system consisted of an acrylic chamber in which to place samples and produce cyclic pressure, viton diaphragm solenoid valves to control the timing of the pressure cycle, and a computer to control electrical devices. The pressure was monitored using a pressure transducer, and the signal was conditioned using a load cell conditioner. A LabVIEW program regulated the pressure using an analog device to pump compressed air into the system at the appropriate rate. The system mimicked the dynamic transvalvular pressure levels associated with the aortic valve; a saw tooth wave produced a gradual increase in pressure, typical of the transvalvular pressure gradient that is present across the valve during diastole, followed by a sharp pressure drop depicting valve opening in systole. The LabVIEW program allowed users to control the magnitude and frequency of cyclic pressure. The system was able to subject tissue samples to physiological and pathological pressure conditions. This device can be used to increase our understanding of how heart valves respond to changes in the local mechanical environment.

Design of a Cyclic Pressure Bioreactor for the Ex Vivo Study of Aortic Heart Valves

A cyclic pressure bioreactor capable of subjecting heart valve tissue to physiological and pathological pressure conditions has been designed. A LabVIEW program allows users to control pressure magnitude, amplitude and frequency. This device can be used to study the mechanobiology of heart valve tissue or isolated cells.

Progettazione di un bioreattore per la pressione ciclica Ex Vivo Studio delle valvole cardiache aortica

The aortic valve, located between the left ventricle and the aorta, allows for unidirectional blood flow, preventing backflow into the ventricle. Aortic ...

Ricerca

Bioingegneria

Ex vivo Mimicry of Normal and Abnormal Human Hematopoiesis

Hematopoietic stem cells require a unique microenvironment in order to sustain blood cell formation1; the bone marrow (BM) is a complex three-dimensional (3D) tissue wherein hematopoiesis is regulated by spatially organized cellular microenvironments termed niches2-4. The organization of the BM niches is critical for the function or dysfunction of normal or malignant BM5. Therefore a better understanding of the in vivo microenvironment using an ex vivo mimicry would help us elucidate the molecular, cellular and microenvironmental determinants of leukemogenesis6.
Currently, hematopoietic cells are cultured in vitro in two-dimensional (2D) tissue culture flasks/well-plates7 requiring either co-culture with allogenic or xenogenic stromal cells or addition of exogenous cytokines8. These conditions are artificial and differ from the in vivo microenvironment in that they lack the 3D cellular niches and expose the cells to abnormally high cytokine concentrations which can result in differentiation and loss of pluripotency9,10.
Herein, we present a novel 3D bone marrow culture system that simulates the in vivo 3D growth environment and supports multilineage hematopoiesis in the absence of exogenous growth factors. The highly porous scaffold used in this system made of polyurethane (PU), facilitates high-density cell growth across a higher specific surface area than the conventional monolayer culture in 2D11. Our work has indicated that this model supported the growth of human cord blood (CB) mononuclear cells (MNC)12 and primary leukemic cells in the absence of exogenous cytokines. This novel 3D mimicry provides a viable platform for the development of a human experimental model to study hematopoiesis and to explore novel treatments for leukemia.

Ex vivo Mimicry of Normal and Abnormal Human Hematopoiesis

A 3D culture system for hematopoiesis is described using human cord blood and leukemic bone marrow cells. The method is based on the use of a porous synthetic polyurethane scaffold coated with extracellular matrix proteins. This scaffold is adaptable to accommodate a wide range of cells.

Ex vivo Mimicry di emopoiesi normale e anormale umana

Hematopoietic stem cells require a unique microenvironment in order to sustain blood cell formation1; the bone marrow (BM) is a complex three-dimensional ...

Determination of the Transport Rate of Xenobiotics and Nanomaterials Across the Placenta using the ex vivo Human Placental Perfusion Model

Decades ago the human placenta was thought to be an impenetrable barrier between mother and unborn child. However, the discovery of thalidomide-induced birth defects and many later studies afterwards proved the opposite. Today several harmful xenobiotics like nicotine, heroin, methadone or drugs as well as environmental pollutants were described to overcome this barrier. With the growing use of nanotechnology, the placenta is likely to come into contact with novel nanoparticles either accidentally through exposure or intentionally in the case of potential nanomedical applications. Data from animal experiments cannot be extrapolated to humans because the placenta is the most species-specific mammalian organ 1. Therefore, the ex vivo dual recirculating human placental perfusion, developed by Panigel et al. in 1967 2 and continuously modified by Schneider et al. in 1972 3, can serve as an excellent model to study the transfer of xenobiotics or particles.
Here, we focus on the ex vivo dual recirculating human placental perfusion protocol and its further development to acquire reproducible results.
The placentae were obtained after informed consent of the mothers from uncomplicated term pregnancies undergoing caesarean delivery. The fetal and maternal vessels of an intact cotyledon were cannulated and perfused at least for five hours. As a model particle fluorescently labelled polystyrene particles with sizes of 80 and 500 nm in diameter were added to the maternal circuit. The 80 nm particles were able to cross the placental barrier and provide a perfect example for a substance which is transferred across the placenta to the fetus while the 500 nm particles were retained in the placental tissue or maternal circuit. The ex vivo human placental perfusion model is one of few models providing reliable information about the transport behavior of xenobiotics at an important tissue barrier which delivers predictive and clinical relevant data.

Determination of the Transport Rate of Xenobiotics and Nanomaterials Across the Placenta using the ex vivo Human Placental Perfusion Model

The ex vivo dual recirculating human placental perfusion model can be used to investigate the transfer of xenobiotics and nanoparticles across the human placenta. In this video protocol we describe the equipment and techniques required for a successful execution of a placenta perfusion.

Determinazione del tasso di trasporto di xenobiotici e nanomateriali attraverso la placenta con il<em&gt; Ex vivo</em&gt; Umano Modello perfusione placentare

Decades ago the human placenta was thought to be an impenetrable barrier between mother and unborn child. However, the discovery of thalidomide-induced ...

Imaging Denatured Collagen Strands In vivo and Ex vivo via Photo-triggered Hybridization of Caged Collagen Mimetic Peptides

Collagen is a major structural component of the extracellular matrix that supports tissue formation and maintenance. Although collagen remodeling is an integral part of normal tissue renewal, excessive amount of remodeling activity is involved in tumors, arthritis, and many other pathological conditions. During collagen remodeling, the triple helical structure of collagen molecules is disrupted by proteases in the extracellular environment. In addition, collagens present in many histological tissue samples are partially denatured by the fixation and preservation processes. Therefore, these denatured collagen strands can serve as effective targets for biological imaging. We previously developed a caged collagen mimetic peptide (CMP) that can be photo-triggered to hybridize with denatured collagen strands by forming triple helical structure, which is unique to collagens. The overall goals of this procedure are i)&#160;to image denatured collagen strands resulting from normal remodeling activities in vivo, and ii) to visualize collagens in ex vivo tissue sections using the photo-triggered caged CMPs. To achieve effective hybridization and successful in vivo and ex vivo imaging, fluorescently labeled caged CMPs are either photo-activated immediately before intravenous injection, or are directly activated on tissue sections. Normal skeletal collagen remolding in nude mice and collagens in prefixed mouse cornea tissue sections are imaged in this procedure. The imaging method based on the CMP-collagen hybridization technology presented here could lead to deeper understanding of the tissue remodeling process, as well as allow development of new diagnostics for diseases associated with high collagen remodeling activity.

Imaging Denatured Collagen Strands In vivo and Ex vivo via Photo-triggered Hybridization of Caged Collagen Mimetic Peptides

This procedure demonstrates in vivo near IR fluorescence imaging of collagen remodeling activities in mice as well as ex vivo staining of collagens in tissue sections using caged collagen mimetic peptides that can be photo-triggered to hybridize with denatured collagen strands.

Imaging denaturate collagene fili<em&gt; In vivo</em&gt; E<em&gt; Ex vivo</em&gt; Via Photo-triggered ibridazione di Caged collagene Mimetic peptidi

Collagen is a major structural component of the extracellular matrix that supports tissue formation and maintenance. Although collagen remodeling is an ...

Biomechanical Characterization of Human Soft Tissues Using Indentation and Tensile Testing

Regenerative medicine aims to engineer materials to replace or restore damaged or diseased organs. The mechanical properties of such materials should mimic the human tissues they are aiming to replace; to provide the required anatomical shape, the materials must be able to sustain the mechanical forces they will experience when implanted at the defect site. Although the mechanical properties of tissue-engineered scaffolds are of great importance, many human tissues that undergo restoration with engineered materials have not been fully biomechanically characterized. Several compressive and tensile protocols are reported for evaluating materials, but with large variability it is difficult to compare results between studies. Further complicating the studies is the often destructive nature of mechanical testing. Whilst an understanding of tissue failure is important, it is also important to have knowledge of the elastic and viscoelastic properties under more physiological loading conditions.
This report aims to provide a minimally destructive protocol to evaluate the compressive and tensile properties of human soft tissues. As examples of this technique, the tensile testing of skin and the compressive testing of cartilage are described. These protocols can also be directly applied to synthetic materials to ensure that the mechanical properties are similar to the native tissue. Protocols to assess the mechanical properties of human native tissue will allow a benchmark by which to create suitable tissue-engineered substitutes.

Tissue biomechanics is important for maintaining cell shape and function and for determining phenotype. This report demonstrates non-destructive mechanical protocols for characterizing elastic and viscoelastic properties of human soft tissues, which can be directly applied to tissue-engineered substrates to allow a close matching of engineered materials to native tissue.

Caratterizzazione biomeccanica di morbidi tessuti umani usando una indentazione e prove di trazione

Regenerative medicine aims to engineer materials to replace or restore damaged or diseased organs. The mechanical properties of such materials should ...

A New Ex Vivo Model for the Evaluation of Endoscopic Submucosal Injection Material Performance

Increasing the performance of submucosal injection materials (SIMs) is important for endoscopic therapy of early gastrointestinal cancer. It is essential to establish an ex vivo model that can evaluate SIM performance accurately, for developing high-performance SIMs. In our previous study, we developed a new ex vivo model that can be used to evaluate the performance of various SIMs in detail by applying constant tension to the specimen&#39;s ends. We also confirmed that the proposed new ex vivo model allows accurate submucosal elevation height (SEH) measurement under uniform conditions and detailed comparisons of the performances of various types of SIMs. Here, we describe the new ex vivo model and explain the detailed setup methodology of this model. Since all parts of the new model were easy to obtain, the setup of the new model could be completed quickly. SEH of various SIMs could be measured more accurately by using the new model. The critical factor that determines SIM performance can be identified using the new model. SIM development speed will drastically increase after the factor has been identified.

A New Ex Vivo Model for the Evaluation of Endoscopic Submucosal Injection Material Performance

We developed a new ex vivo model that applies constant tension to the porcine gastric specimen. This development made it possible to evaluate the performance (the height and duration of the submucosal elevation) of various SIMs accurately.&#160; The detailed setup methodology of this new model is explained.

Un nuovo modello Ex Vivo per la valutazione delle prestazioni del materiale di iniezione sottomucosa endoscopica

Increasing the performance of submucosal injection materials (SIMs) is important for endoscopic therapy of early gastrointestinal cancer. It is essential ...

Detection of Endotoxin in Nano-formulations Using Limulus Amoebocyte Lysate (LAL) Assays

When present in pharmaceutical products, a Gram-negative bacterial cell wall component endotoxin (often also called lipopolysaccharide) can cause inflammation, fever, hypo- or hypertension, and, in extreme cases, can lead to tissue and organ damage that may become fatal. The amounts of endotoxin in pharmaceutical products, therefore, are strictly regulated. Among the methods available for endotoxin detection and quantification, the Limulus Amoebocyte Lysate (LAL) assay is commonly used worldwide. While any pharmaceutical product can interfere with the LAL assay, nano-formulations represent a particular challenge due to their complexity. The purpose of this paper is to provide a practical guide to researchers inexperienced in estimating endotoxins in engineered nanomaterials and nanoparticle-formulated drugs. Herein, practical recommendations for performing three LAL formats including turbidity, chromogenic and gel-clot assays are discussed. These assays can be used to determine endotoxin contamination in nanotechnology-based drug products, vaccines, and adjuvants.

Detection of Endotoxin in Nano-formulations Using Limulus Amoebocyte Lysate LAL Assays

Detection of endotoxins in engineered nanomaterials represents one of the grand challenges in the field of nanomedicine. Here, we present a case study that describes the framework composed of three different LAL formats to estimate potential endotoxin contamination in nanoparticles.

Rilevamento dell'endotossina in Nano-formulazioni utilizzando dosaggi di Limulus Amoebocyte Lysate (LAL)

When present in pharmaceutical products, a Gram-negative bacterial cell wall component endotoxin (often also called lipopolysaccharide) can cause ...

Methods for In Vivo Biomechanical Testing on Brachial Plexus in Neonatal Piglets

Neonatal brachial plexus palsy (NBPP) is a stretch injury that occurs during the birthing process in nerve complexes located in the neck and shoulder regions, collectively referred to as the brachial plexus (BP). Despite recent advances in obstetrical care, the problem of NBPP continues to be a global health burden with an incidence of 1.5 cases per 1,000 live births. More severe types of this injury can cause permanent paralysis of the arm from the shoulder down. Prevention and treatment of NBPP warrants an understanding of the biomechanical and physiological responses of newborn BP nerves when subjected to stretch. Current knowledge of the newborn BP is extrapolated from adult animal or cadaveric BP tissue instead of in vivo neonatal BP tissue. This study describes an in vivo mechanical testing device and procedure to conduct in vivo biomechanical testing in neonatal piglets. The device consists of a clamp, actuator, load cell, and camera system that apply and monitor in vivo strains and loads until failure. The camera system also allows monitoring of the failure location during rupture. Overall, the presented method allows for a detailed biomechanical characterization of neonatal BP when subjected to stretch.

Methods for In Vivo Biomechanical Testing on Brachial Plexus in Neonatal Piglets

Presented here are methods to perform in vivo biomechanical testing on brachial plexus in a neonatal piglet model.

Metodi per il test biomeccanico In Vivo su plexus brachiale in porcellini neoatali

Neonatal brachial plexus palsy (NBPP) is a stretch injury that occurs during the birthing process in nerve complexes located in the neck and shoulder ...

Synthesis of Graphene-Hydroxyapatite Nanocomposites for Potential Use in Bone Tissue Engineering

Developing novel materials for bone tissue engineering is one of the most important thrust areas of nanomedicine. Several nanocomposites have been fabricated with hydroxyapatite to facilitate cell adherence, proliferation, and osteogenesis. In this study, hybrid nanocomposites were successfully developed using graphene nanoribbons (GNRs) and nanoparticles of hydroxyapatite (nHAPs), that when employed in bioactive scaffolds may potentially improve bone tissue regeneration. These nanostructures can be biocompatible. Here, two approaches were used for preparing the novel materials. In one approach, a co-functionalization strategy was used where nHAP was synthesized and conjugated to GNRs simultaneously, resulting in nanohybrids of nHAP on GNR surfaces (denoted as nHAP/GNR). High-resolution transmission electron microscopy (HRTEM) confirmed that the nHAP/GNR composite is comprised of slender, thin structures of GNRs (maximum length of 1.8 &#181;m) with discrete patches (150-250 nm) of needle-like nHAP (40-50 nm in length). In the other approach, commercially available nHAP was conjugated with GNRs forming GNR-coated nHAP (denoted as GNR/nHAP) (i.e., with an opposite orientation relative to the nHAP/GNR nanohybrid). The nanohybrid formed using the latter method exhibited nHAP nanospheres with a diameter ranging from 50 nm to 70 nm covered with a network of GNRs on the surface. Energy dispersive spectra, elemental mapping, and Fourier transform infrared (FTIR) spectra confirmed the successful integration of nHAP and GNRs in both nanohybrids. Thermogravimetric analysis (TGA) indicated that the loss at elevated heating temperatures due to the presence of GNRs was 0.5% and 0.98% for GNR/nHAP and nHAP/GNR, respectively. The nHAP-GNR nanohybrids with opposite orientations represent significant materials for use in bioactive scaffolds to potentially promote cellular functions for improving bone tissue engineering applications.

Novel nanocomposites of graphene nanoribbons and hydroxyapatite nanoparticles were prepared using solution-phase synthesis. These hybrids when employed in bioactive scaffolds can exhibit potential applications in tissue engineering and bone regeneration.

Sintesi di nanocompositi di grafene-idrossiapatite per un potenziale utilizzo nell'ingegneria dei tessuti ossei

Developing novel materials for bone tissue engineering is one of the most important thrust areas of nanomedicine. Several nanocomposites have been ...

Strategie di controllo e monitoraggio microbico per ambienti di camere bianche

Microbial Control and Monitoring Strategies for Cleanroom Environments and Cellular Therapies

A well-validated and holistic program that incorporates robust gowning, cleaning, environmental monitoring, and personnel monitoring measures is critical for minimizing the microbial bioburden in cellular therapy manufacturing suites and the corresponding testing laboratories to ensure that the facilities are operating in a state of control. Ensuring product safety via quality control measures, such as sterility testing, is a regulatory requirement for both minimally manipulated (section 361) and more than minimally manipulated (section 351) human cells, tissues, and cellular and tissue-based products (HCT/Ps). In this video, we provide a stepwise guide for how to develop and incorporate the best aseptic practices for operating in a cleanroom environment, including gowning, cleaning, staging of materials, environmental monitoring, process monitoring, and product sterility testing using direct inoculation, provided by the United States Pharmacopeia (USP&lt;71&gt;) and the National Institutes of Health (NIH) Alternative Sterility Testing Method. This protocol is intended as a reference guide for establishments expected to meet current good tissue practices (cGTP) and current good manufacturing practices (cGMP).

Autore in primo piano: Strategie di controllo e monitoraggio microbico per ambienti di camere bianche e terapie cellulari  

The protocol summarizes the best practices to minimize microbial bioburden in a cleanroom environment and includes strategies such as environmental monitoring, process monitoring, and product sterility testing. It is relevant for manufacturing and testing facilities that are required to meet current good tissue practice standards and current good manufacturing practice standards.

Controllo microbico e strategie di monitoraggio per ambienti di camere bianche e terapie cellulari

A well-validated and holistic program that incorporates robust gowning, cleaning, environmental monitoring, and personnel monitoring measures is critical ...