Questo materiale si basa sul lavoro sostenuto dal Dipartimento dell&#39;Energia degli Stati Uniti, Scienze dei Materiali e Ingegneria Divisione (n ° Premio DEFG-02-07ER46471) e il DOE Energy Center ricerca sulle interazioni luce-Materiali in Energy Conversion (Premio n ° DE-SC0001293 ), e ha beneficiato di accesso al Centro per la microanalisi dei materiali all&#39;interno del Frederick Seitz Materials Research Laboratory (FSMRL).

1. Introduzione <ol><li> Questo documento dimostra la 1D, 2D, 3D e la stampa di microelettrodi conduttivo via diretta-scrittura di montaggio. </li><li> Diretta-scrittura di montaggio è un metodo di creazione di strutture stampate 1D-to-3D dalla deposizione di inchiostri concentrati attraverso ugelli fine. </li><li> Il nostro sistema è costituito da un computer controllato a 3 assi fase di traduzione, un serbatoio di inchiostro e di ugello, e 10x lente telescopica per l&#39;imaging (Figura 1). </li><li> Diretta-scrittura di montaggio è un approccio di stampa filamentosi in cui sono concentrati gli inchiostri estruso attraverso ugelli cilindrici, i cui diametri vanno dal 0,1-250 micron (Figura 2). In particolare, a causa delle caratteristiche di inchiostro il viscoelastico, diretto-scrittura di montaggio consente autoportante caratteristiche spanning (Figura 3). Fino ad oggi, una vasta gamma di inchiostri, compresi quelli composti da ceramica 6,7, 8-10 organici, metallici 11-15, polimerici 16,17, e sol-gel 18,19 materiali sono statisviluppato per questo approccio stampa (Figura 4). </li></ol> 2. Preparazione di inchiostri ad alta concentrazione di nanoparticelle d&#39;argento <ol><li> Gli inchiostri di nanoparticelle d&#39;argento sono preparati per prima cosa sciogliere una miscela di 5.000 e 50.000 peso molecolare di poli (acido acrilico) in una miscela di 50 g di acqua e 40 g dietanolammina (Video 2.1). </li><li> Il polimero si comporta come un agente di capping per controllare le dimensioni delle nanoparticelle d&#39;argento. </li><li> Quindi, una soluzione acquosa di nitrato d&#39;argento viene iniettato nella soluzione polimerica. Dopo l&#39;aggiunta, una luce gialla trasparente soluzione si ottiene (Video 2.2). </li><li> Dopo aver agitato per 24 ore a temperatura ambiente, la soluzione sviluppa un colore bruno-rossastro (Video 2.3), che coincide con la formazione di nanoparticelle d&#39;argento del diametro 5 nm, determinata mediante microscopia elettronica a trasmissione. </li><li> Quindi, la soluzione è sonicato a 65 ° C a bagnomaria per 2 ore per la crescita ulteriore di particelle (Video 2.4). </li><li> After sonicazione, la soluzione è trasferito in un bicchiere da 500 ml e raffreddato a temperatura ambiente. Allora da 300 ml di etanolo è titolato ad una velocità di 30 ml / min. Dal momento che l&#39;etanolo è un solvente poveri per il poli (acido acrilico) agente di capping, le particelle di coagulare rapidamente e precipitare dalla soluzione (Video 2.5). </li><li> Dopo la decantazione il surnatante, il precipitato è raccolto in una provetta da centrifuga e centrifugati a 9000 rpm per 20 minuti (Video 2.6). </li><li> Dopo questo passaggio, un inchiostro ad alta concentrazione di nanoparticelle d&#39;argento con un solido carico di ~ 85% in peso si ottiene (Video 2.7). </li><li> Un ulteriore controllo sulla viscosità dell&#39;inchiostro e modulo elastico può essere ottenuto mediante diluizione, seguiti da omogeneizzazione. Per un esempio, una soluzione umettante, come ad esempio glicole etilenico, può essere aggiunto l&#39;inchiostro e poi omogeneizzato a 2000 giri al minuto 3 minuti utilizzando un mixer Thinky omogeneizzazione. Dopo questo processo, un inchiostro uniforme di un colore bluastro al magenta si ottiene (Video 2.8). </li><li> L&#39;immagine TEM mostrananoparticelle d&#39;argento ottenute da questa procedura di sintesi (Figura 5_left). Le particelle hanno un diametro medio di 20 nm con una distribuzione delle dimensioni di 50-50 nm. Strutture stampate richiedono post-ricottura per migliorare la loro conducibilità. Dopo la ricottura a 250 ° C per meno di 30 minuti, le nanoparticelle d&#39;argento forma microelettrodi conduttivo con una resistività elettrica si avvicina al 10 -5 Ω • cm (figura a destra 5_bottom). L&#39;evoluzione microstrutturale dei microelettrodi argento stampato in funzione della temperatura di ricottura è mostrato nella figura a destra 5_top. Quando la temperatura aumenta da 150 ° a 550 ° C, la densificazione con microelettrodi subiscono una contrazione volumetrica totale di ~ 30% 11. </li><li> La reologia inchiostro, che dipende fortemente dal suo carico di solidi, ne determina la stampabilità. L&#39;inchiostro viscosità aumenta con l&#39;aumentare del carico di solidi (Figura 6). Perché diluire gli inchiostri a bassa viscosità con risultato in una significativa diffusione laterale, Concentrazioneinchiostri ated con un carico di solidi da 70 a 85% in peso sono necessari per la stampa di filamenti inchiostro planari e si estende. </li><li> L&#39;inchiostro modulo elastico aumenta con l&#39;aumentare del carico di solidi (Figura 7). Nella regione viscoelastico lineare, il modulo elastico aumenta di quasi tre ordini di grandezza come i solidi di carico aumenta 60 al 75% in peso. Un modulo elastico minimo di 2000 Pa è necessaria per produrre autoportanti o spanning caratteristiche. </li></ol> 3. Diretta-scrittura di assemblaggio <ol><li> Diretta-scrittura assemblaggio è effettuato da caricare prima l&#39;inchiostro in una siringa. Dopo aver fissato un ugello di deposizione, l&#39;inchiostro-caricati siringa è montato sul 3-asse fase di stampa (Video 3.1). </li><li> Usando un programma per computer, i disegni arbitrari, compresi lineari, planari e complesse strutture tridimensionali possono essere facilmente generati (Video 3.2). </li><li> Successivamente, l&#39;altezza dell&#39;ugello viene regolata con l&#39;ausilio di lente del telescopio con uno zoom 10x (Video 3.3). </lI&gt; <li> Dopo l&#39;applicazione di pressione utilizzando un impianto di alimentazione del sistema di distribuzione dei fluidi, l&#39;inchiostro si deposita sul substrato, con una velocità di stampa controllata (Video 3.4). La pressione necessaria dipende reologia inchiostro, diametro dell&#39;ugello e la velocità di stampa, ma i valori tipici gamma 10-100 psi a 20-500 micron / s. Questa stampa viene eseguita in aria a temperatura ambiente. Utilizzando questa procedura di stampa, la stampa di microelettrodi d&#39;argento in diversi layout e scale di grandezza è dimostrata. </li><li> Per un esempio, la stampa di griglie d&#39;argento conduttiva con un centro a centro interlinea di 100 micron, modellata da un ugello di 5 micron su un substrato di wafer di silicio è dimostrato (Video 3.5). </li><li> Inoltre, questo video mostra come creare una struttura di alto rapporto di aspetto cilindrico da un ugello di 30 micron utilizzando un layer-by-layer metodo di stampa (Video 3.6). </li><li> Inoltre, la stampa omnidirezionale di microelettrodi d&#39;argento tra due substrati di vetro compensato da un altezza di 1 mm difference è dimostrato utilizzando un ugello di 30 micron (Video 3.7). </li><li> Completamente free-standing, microspikes argento verticalmente stampata può essere creato da un ugello di 30 micron su un substrato di wafer silicio (Video 3.8). </li><li> Infine, questo video mostra la scrittura diretta di un microelettrodo argento si estende con un 10-micron ugello (Video 3.9). La funzione stampata può coprire distanze fino a uno centimetri con un minimo cadenti o deformazione. </li></ol> 4. Rappresentante dei risultati: Abbiamo preparato una inchiostri ad alta concentrazione di nanoparticelle d&#39;argento e ha dimostrato caratteristiche di conduttore stampato in motivi planare e 3D per applicazioni elettroniche e optoelettronici con risoluzione di stampa ~ 2-30 micron. Per un esempio, Figura 8 mostra la risoluzione di stampa di questa tecnica. Caratteristiche stampati con larghezza minima di elettrodi di circa 2 micron (1,4 micron di spessore) si ottengono in un unico passaggio con un 1-micron ugello 11. Figura 9 mostranos griglie argento conduttivo trasparente, modellata da un ugello di 5 micron su una pellicola flessibile poliammide 12. I testi sotto le griglie stampate sono chiaramente visibili. Queste griglie argento trasparente potevano essere alternative interessanti per lo svolgimento di ossido trasparente (TCO) dei materiali. Conformazionale stampa su una non-planare substrati viene attivato anche da questo metodo. Figura 10 mostra la stampa conformazionale di un&#39;antenna 3D elettrico di piccole dimensioni. A 100 micron ugello in metallo consente di stampare meandro-line i modelli sulla superficie di un bicchiere emisfero 13. Questo approccio può trovare numerose applicazioni tra cui antenne impiantabili e portabili, elettronica e sensori. Applicazioni di microelettrodi d&#39;argento si estende in tre dimensioni fotovoltaico e diodi luminosi sono dimostrati (Figura 11-14). In primo luogo, figura 11 è un esempio di guscio di silicio sferica. Questo film tenue con un 2-micron thickness può essere filo-legato ad un circuito esterno di stampa omnidirezionale 14. Questo metodo utilizza la pressione minima di contatto, che è molto vantaggioso per i dispositivi delicati. Successivamente, figura 12 mostra un esempio di stampa di una interconnessione si estende per una vasta microcelle solari al silicio in cui sono separati silicio elementi microribbon da 33 micron-gap 15. Successivamente, figura 13 mostra d&#39;argento interconnessioni per l&#39;arseniuro di gallio-array basato LED con 4-by-4 pixel, in cui ciascun pixel (500 x 500 x 2,5 micron 3) è spaziato 200 micron oltre 11. L&#39;immagine in basso mostra la matrice di LED, che emettono luce rossa uniforme sotto una polarizzazione applicata di 6 V da un singolo pixel. La capacità di stampare elettrodi spanning permette l&#39;interconnessione multistrato senza l&#39;uso di strati di supporto o sacrificale (foto sopra). A dimostrazione finale, La figura 14 mostra le immagini SEM per il microfono complesso 3Dreticolo argento roperiodic stampato da un ugello di 5 micron. <img alt="Figura 1" src="/files/ftp_upload/3189/3189fig1.jpg" /> Figura 1. Immagine ottico degli apparecchi diretto scrittura inchiostro. <img alt="Figura 2" src="/files/ftp_upload/3189/3189fig2.jpg" /> Figura 2. Scrittura inchiostro diretta di una caratteristica filamentosi. <img alt="Figura 3" src="/files/ftp_upload/3189/3189fig3.jpg" /> Figura 3. Scrittura diretta di inchiostro autoportanti caratteristiche spanning. <img alt="Figura 4" src="/files/ftp_upload/3189/3189fig4.jpg" /> Figura 4. Disegni di inchiostro per la scrittura di inchiostro diretto. Una vasta gamma di inchiostri viscoelastico concentrato sono stati sviluppati per la scrittura diretta di strutture 3D planari e complessi con caratteristiche di microscala. <img alt="Figura 5" src="/files/ftp_upload/3189/3189fig5.jpg" /> Figura 5. (Sinistra), microscopia elettronica a trasmissione (TEM) immagine di nanoparticelle d&#39;argento. (In alto a destra) SEM immagini di microelettrodi in argento modellato con un ugello di 15 micron in funzione della temperatura di ricottura. (In basso a destra) resistività elettrica di microelettrodi d&#39;argento in funzione della temperatura e tempo di ricottura. <img alt="Figura 6" src="/files/ftp_upload/3189/3189fig6.jpg" /> Figura 6. Viscosità apparente (η), degli inchiostri nanoparticelle d&#39;argento in funzione del carico solidi. <img alt="Figura 7" src="/files/ftp_upload/3189/3189fig7.jpg" /> Figura 7. Shear modulo elastico (G &#39;) in funzione dello sforzo di taglio per gli inchiostri di nanoparticelle d&#39;argento di varia carico solidi. <img alt="Figura 8" src="/files/ftp_upload/3189/3189fig8.jpg" /> Figura 8. Immagini SEM delle matrici di microelettrodi planari argento modellatasu un wafer di silicio con un ugello di 1 micron. <img alt="Figura 9" src="/files/ftp_upload/3189/3189fig9.jpg" /> Figura 9. Ottica delle immagini di griglie argento trasparente conduttivo (a sinistra) e le immagini SEM delle griglie stampate in funzione del passo della linea (a destra). <img alt="Figura 10" src="/files/ftp_upload/3189/3189fig10.jpg" /> Figura 10. Ottica delle immagini catturate durante la stampa conformazionale di antenne elettricamente piccolo su un substrato di vetro emisferica. <img alt="Figura 11" src="/files/ftp_upload/3189/3189fig11.jpg" /> Figura 11. Ottica delle immagini ottenute durante la stampa di microelettrodi d&#39;argento si estende su una sottile (2-micron) guscio di silicio sferica. <img alt="Figura 12" src="/files/ftp_upload/3189/3189fig12.jpg" /> Figura 12. Immagine SEM di un microelettrodo argento si estende stampato su un silicio in modolare Microcell array. <img alt="Figura 13" src="/files/ftp_upload/3189/3189fig13.jpg" /> Figura 13. Immagini SEM (in alto) e immagine ottico (in basso) di un-4 by-4 serie chip LED collegati tra loro da microelettrodi d&#39;argento. <img alt="Figura 14" src="/files/ftp_upload/3189/3189fig14.jpg" /> Figura 14. Immagine SEM di reticolo argento microperiodic 3D.

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Mater. 21, 47-54 (2011).</li><li>Wu, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Direct-write+assembly+of+biomimetic+microvascular+networks+for+efficient+fluid+transport.">Direct-write assembly of biomimetic microvascular networks for efficient fluid transport.</a> Soft. Matter. 6, 739-742 (2010).</li><li>Wu, W., DeConinck, A., Lewis, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Omnidirectional+Printing+of+3D+Microvascular+Networks.">Omnidirectional Printing of 3D Microvascular Networks.</a> Adv. Mater. 23, H178-H183 (2011).</li></ol>

Nessun conflitto di interessi dichiarati.

Convenzionali goccia approcci basati stampa, come la stampa a getto d&#39;inchiostro, sono limitate alla realizzazione di elettrodi planari con aspect ratio bassa a causa della natura diluire e bassa viscosità degli inchiostri utilizzati. Recentemente, dip-pen nanolitografia (DPN) e 20-22 e 23-25 ​​a getto d&#39;inchiostro sono stati utilizzati per funzioni di modello conduttivo. Questi percorsi utilizzano anche diluire, inchiostri a bassa viscosità. Pearton e collaboratori utilizzati DPN per depositare un normale inchiostro nanoparticelle d&#39;argento alla velocità di scrittura fino a 1600 micron s -1 e larghezze di linea di circa 0,5 micron 22. Tuttavia, la fabbricazione di modelli riproducibili su grandi aree deve ancora essere dimostrato da questo approccio. Gli inchiostri di nanoparticelle d&#39;argento sono stati depositati per posta a getto d&#39;inchiostro per formare le tracce conduttive con larghezza delle linee di ~ 1,5 micron 25. Tuttavia, come con la stampa a getto d&#39;inchiostro, stampate caratteristiche disomogenee possono insorgere a causa della formazione di gocce satellite e non uniforme goccia drying 24,25. Come dimostrato sopra, diretta-scrittura assemblaggio di inchiostri concentrati nanoparticelle d&#39;argento supera questi limiti attraverso un approccio basato filamentosi stampa. Questa tecnica permette la fabbricazione di microelettrodi conduttivo con un aspect ratio alta (h / w ≈ 1,0) in un singolo passaggio permettendo la creazione di codici 1D, 2D, 3D e architetture. La dimensione delle caratteristiche stampata dipende diametro dell&#39;ugello, inchiostro di carico solidi, pressione applicata, e velocità di stampa. Ad oggi, le tracce conduttive piccolo come ~ 2 micron sono stati modellati utilizzando un ugello 1 micron a velocità modesta (&lt;2 mm s -1). Adattando la composizione dell&#39;inchiostro e la geometria degli ugelli, la velocità di stampa massime superiori a -1 10 cm s sono possibili. Tuttavia, la stampa ad alta velocità di utilizzare ugelli fine (&lt;5 micron) rimane una sfida significativa. Per dimostrare di applicazioni diretta-scrittura di assemblaggio, abbiamo inventato griglie conduttrici, elantenne ectrically piccole celle solari e diodi emettitori di luce con elettrodi planari stampata e si estende (figura 8-14). In particolare, il nostro approccio non si limita alla creazione di strutture metalliche. Utilizzando i disegni di inchiostro, diversi, come quelli basati su fibroina di seta, idrogel e latitante inchiostri organici, abbiamo costruito ponteggi e reti microvascolare 3D per l&#39;ingegneria tissutale e colture cellulari via diretta-scrittura di montaggio 26-30. Guardando al futuro, ci sono molte opportunità e sfide. Ulteriori progressi richiedono design nuovo inchiostro, una migliore modellazione delle dinamiche del flusso d&#39;inchiostro, e la realizzazione di sistemi robotici e di controllo. Ampia superficie fabbricazione di strutture 1D a 3D con un throughput elevato e risoluzione nanometrica (&lt;100 nm) rimane una sfida significativa.

<table border="1"><tr><td> Nome del reagente </td><td> Azienda </td><td> Numero di catalogo </td><td> Commenti </td></tr><tr><td> Poli (acido acrilico) </td><td> Polysciences, Inc. </td><td> 06519 </td><td> mw 5.000 g / mol </td></tr><tr><td> Poli (acido acrilico) </td><td> Polysciences, Inc. </td><td> 00627 </td><td> mw 50.000 g / mol </td></tr><tr><td> Nitrato d&#39;argento </td><td> Sigma-Aldrich </td><td> 209139 </td><td> Fonte d&#39;argento </td></tr><tr><td> Dietanolammina </td><td> Sigma-Aldrich </td><td> D8885 </td><td> Solvente / agente riducente </td></tr><tr><td> Glicole etilenico </td><td> Sigma-Aldrich </td><td> 102466 </td><td> Umettante </td></tr><tr><td> Sonicater </td><td> Fisher Scientific </td><td> FS30H </td><td> - </td></tr><tr><td> Centrifuga </td><td> Beckman Coulter </td><td> Avanti TM J-25 I </td><td> - </td></tr><tr><td> Fase di robotica </td><td> Aerotech Inc. </td><td> ABL 900010 </td><td> Movimento su 3 assi </td></tr><tr><td>Il corpo della siringa </td><td> EFD Inc. </td><td> 5109LBP-B </td><td> 3 ml </td></tr><tr><td> Ugello </td><td> EFD Inc. </td><td> - </td><td> id = 0,1-250 micron </td></tr><tr><td> Distributore </td><td> EFD Inc. </td><td> 800 </td><td> Air-powered </td></tr><tr><td> Progettazione del software </td><td> Progettato su misura </td><td> - </td><td> Mingjie Xu </td></tr></table>

planar and three-dimensional printing of conductive inks

Elettronica stampata si affidano a basso costo, grandi superfici per creare percorsi di fabbricazione flessibili o multidimensionali elettronici, optoelettronici e dispositivi biomedici 1-3. In questo lavoro, ci concentriamo su un-(1D), due-(2D) e tridimensionali (3D) stampa di inchiostri conduttivi metallici a forma di microelettrodi flessibile, elastico, e si estende. Diretta-scrittura di montaggio 4,5 è un 1-a-3D tecnica di stampa che permette la realizzazione di funzioni che vanno da linee semplici a strutture complesse per la deposizione di inchiostri concentrati attraverso ugelli fine (~ 0,1-250 micron). Questo metodo di stampa è costituito da un computer controllato a 3 assi fase di traduzione, un serbatoio di inchiostro e di ugello, e 10x lente telescopica per la visualizzazione. A differenza della stampa a getto d&#39;inchiostro, una gocciolina processo basato, diretta-scrittura di assemblaggio comporta l&#39;estrusione di filamenti d&#39;inchiostro sia in o out-of-plane. I filamenti di solito stampato conforme alle dimensioni dell&#39;ugello. HENCe, caratteristiche microscala (&lt;1 micron) possono essere stampati e assemblati in grandi array multidimensionali e architetture. In questo lavoro, abbiamo prima sintetizzare un inchiostro ad alta concentrazione di nanoparticelle d&#39;argento per la stampa planare e 3D via diretta-scrittura di montaggio. Poi, un protocollo standard per la stampa microelettrodi in motivi multidimensionale è dimostrata. Infine, le applicazioni di microelettrodi per antenne stampate elettricamente piccole celle solari e diodi emettitori di luce sono evidenziati.

Watch this Scientific Journal Video about Planar and Three-Dimensional Printing of Conductive Inks at JoVE.com

Planar and Three-Dimensional Printing of Conductive Inks

Stampa planare e tridimensionale di inchiostri conduttivi metallici è descritto. Il nostro approccio offre nuove strade per la realizzazione di stampati elettronici, optoelettronici e dispositivi biomedici nei layout insolito alla microscala.

Stampa planare e tridimensionale di inchiostri conduttivi

Printed electronics rely on low-cost, large-area fabrication routes to create flexible or multidimensional electronic, optoelectronic, and biomedical ...

planar-and-three-dimensional-printing-of-conductive-inks

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JoVE Journal

Bioengineering

37.0K Views.  University of Illinois at Urbana-Champaign. Stampa planare e tridimensionale di inchiostri conduttivi metallici è descritto. Il nostro approccio offre nuove strade per la realizzazione di stampati elettronici, optoelettronici e dispositivi biomedici nei layout insolito alla microscala.

Video: Planar and Three-Dimensional Printing of Conductive Inks

Three-dimensional Optical-resolution Photoacoustic Microscopy

Optical microscopy, providing valuable insights at the cellular and organelle levels, has been widely recognized as an enabling biomedical technology. As the mainstays of in vivo three-dimensional (3-D) optical microscopy, single-/multi-photon fluorescence microscopy and optical coherence tomography (OCT) have demonstrated their extraordinary sensitivities to fluorescence and optical scattering contrasts, respectively. However, the optical absorption contrast of biological tissues, which encodes essential physiological/pathological information, has not yet been assessable. 
The emergence of biomedical photoacoustics has led to a new branch of optical microscopy optical-resolution photoacoustic microscopy (OR-PAM)1, where the optical irradiation is focused to the diffraction limit to achieve cellular1 or even subcellular2 level lateral resolution. As a valuable complement to existing optical microscopy technologies, OR-PAM brings in at least two novelties. First and most importantly, OR-PAM detects optical absorption contrasts with extraordinary sensitivity (i.e., 100%). Combining OR-PAM with fluorescence microscopy3 or with optical-scattering-based OCT4 (or with both) provides comprehensive optical properties of biological tissues. Second, OR-PAM encodes optical absorption into acoustic waves, in contrast to the pure optical processes in fluorescence microscopy and OCT, and provides background-free detection. The acoustic detection in OR-PAM mitigates the impacts of optical scattering on signal degradation and naturally eliminates possible interferences (i.e., crosstalks) between excitation and detection, which is a common problem in fluorescence microscopy due to the overlap between the excitation and fluorescence spectra. 
Unique for optical absorption imaging, OR-PAM has demonstrated broad biomedical applications since its invention, including, but not limited to, neurology5, 6, ophthalmology7, 8, vascular biology9, and dermatology10. In this video, we teach the system configuration and alignment of OR-PAM as well as the experimental procedures for in vivo functional microvascular imaging.

Optical-resolution photoacoustic microscopy (OR-PAM) is an emerging technology capable of imaging optical absorption contrasts in vivo with cellular resolution and sensitivity. Here, we provide a visualized instruction on the experimental protocols of OR-PAM, including system configuration, system alignment, typical in vivo experimental procedures, and functional imaging schemes.

Tridimensionale con risoluzione ottica Microscopia fotoacustico

Optical microscopy, providing valuable insights at the cellular and organelle levels, has been widely recognized as an enabling biomedical technology. As ...

Ricerca

Bioingegneria

Alginate Hydrogels for Three-Dimensional Organ Culture of Ovaries and Oviducts

Ovarian cancer is the fifth leading cause of cancer deaths in women and has a 63% mortality rate in the United States1. The cell type of origin for ovarian cancers is still in question and might be either the ovarian surface epithelium (OSE) or the distal epithelium of the fallopian tube fimbriae2,3. Culturing the normal cells as a primary culture in vitro will enable scientists to model specific changes that might lead to ovarian cancer in the distinct epithelium, thereby definitively determining the cell type of origin. This will allow development of more accurate biomarkers, animal models with tissue-specific gene changes, and better prevention strategies targeted to this disease.
Maintaining normal cells in alginate hydrogels promotes short term in vitro culture of cells in their three-dimensional context and permits introduction of plasmid DNA, siRNA, and small molecules. By culturing organs in pieces that are derived from strategic cuts using a scalpel, several cultures from a single organ can be generated, increasing the number of experiments from a single animal. These cuts model aspects of ovulation leading to proliferation of the OSE, which is associated with ovarian cancer formation. Cell types such as the OSE that do not grow well on plastic surfaces can be cultured using this method and facilitate investigation into normal cellular processes or the earliest events in cancer formation4.
Alginate hydrogels can be used to support the growth of many types of tissues5. Alginate is a linear polysaccharide composed of repeating units of &beta;-D-mannuronic acid and &alpha;-L-guluronic acid that can be crosslinked with calcium ions, resulting in a gentle gelling action that does not damage tissues6,7. Like other three-dimensional cell culture matrices such as Matrigel, alginate provides mechanical support for tissues; however, proteins are not reactive with the alginate matrix, and therefore alginate functions as a synthetic extracellular matrix that does not initiate cell signaling5. The alginate hydrogel floats in standard cell culture medium and supports the architecture of the tissue growth in vitro.
A method is presented for the preparation, separation, and embedding of ovarian and oviductal organ pieces into alginate hydrogels, which can be maintained in culture for up to two weeks. The enzymatic release of cells for analysis of proteins and RNA samples from the organ culture is also described. Finally, the growth of primary cell types is possible without genetic immortalization from mice and permits investigators to use knockout and transgenic mice.

Culture of normal cells in their three-dimensional context represents an alternative method to study early events required for cellular transformation and tumorigenesis. This method is used to grow normal ovarian and oviductal cells to study early events in ovarian cancer formation.

Idrogeli di alginato per tridimensionale Cultura Organo di ovaie e tube

Ovarian cancer is the fifth leading cause of cancer deaths in women and has a 63% mortality rate in the United States1. The cell type of origin for ...

Investigating the Three-dimensional Flow Separation Induced by a Model Vocal Fold Polyp

The fluid-structure energy exchange process for normal speech has been studied extensively, but it is not well understood for pathological conditions. Polyps and nodules, which are geometric abnormalities that form on the medial surface of the vocal folds, can disrupt vocal fold dynamics and thus can have devastating consequences on a patient&#39;s ability to communicate. Our laboratory has reported particle image velocimetry (PIV) measurements, within an investigation of a model polyp located on the medial surface of an in&#160;vitro driven vocal fold model, which show that such a geometric abnormality considerably disrupts the glottal jet behavior. This flow field adjustment is a likely reason for the severe degradation of the vocal quality in patients with polyps. A more complete understanding of the formation and propagation of vortical structures from a geometric protuberance, such as a vocal fold polyp, and the resulting influence on the aerodynamic loadings that drive the vocal fold dynamics, is necessary for advancing the treatment of this pathological condition. The present investigation concerns the three-dimensional flow separation induced by a wall-mounted prolate hemispheroid with a 2:1 aspect ratio in cross flow, i.e. a model vocal fold polyp, using an oil-film visualization technique. Unsteady, three-dimensional flow separation and its impact of the wall pressure loading are examined using skin friction line visualization and wall pressure measurements.

Vocal fold polyps can disrupt vocal fold dynamics and thus can have devastating consequences on a patient&#39;s ability to communicate. Three-dimensional flow separation induced by a wall-mounted model polyp and its impact on the wall pressure loading are examined using particle image velocimetry, skin friction line visualization, and wall pressure measurements.

Investigare la separazione tridimensionale del flusso indotta da un modello di polipo piega vocale

The fluid-structure energy exchange process for normal speech has been studied extensively, but it is not well understood for pathological conditions. ...

Human Cartilage Tissue Fabrication Using Three-dimensional Inkjet Printing Technology

Bioprinting, which is based on thermal inkjet printing, is one of the most attractive enabling technologies in the field of tissue engineering and regenerative medicine. With digital control&#160;cells, scaffolds, and growth factors can be precisely deposited to the desired two-dimensional (2D) and three-dimensional (3D) locations rapidly. Therefore, this technology is an ideal approach to fabricate tissues mimicking their native anatomic structures. In order to engineer cartilage with native zonal organization, extracellular matrix composition (ECM), and mechanical properties, we developed a bioprinting platform using a commercial inkjet printer with simultaneous photopolymerization capable for 3D cartilage tissue engineering. Human chondrocytes suspended in poly(ethylene glycol) diacrylate (PEGDA) were printed for 3D neocartilage construction via layer-by-layer assembly. The printed cells were fixed at their original deposited positions, supported by the surrounding scaffold in simultaneous photopolymerization. The mechanical properties of the printed tissue were similar to the native cartilage. Compared to conventional tissue fabrication, which requires longer UV exposure, the viability of the printed cells with simultaneous photopolymerization was significantly higher. Printed neocartilage demonstrated excellent glycosaminoglycan (GAG) and collagen type II production, which was consistent with gene expression. Therefore, this platform is ideal for accurate cell distribution and arrangement for anatomic tissue engineering.

The methods described in this paper show how to convert a commercial inkjet printer into a bioprinter with simultaneous UV polymerization. The printer is capable of constructing 3D tissue structure with cells and biomaterials. The study demonstrated here constructed a 3D neocartilage.

Umana Cartilagine Tessuto Fabrication Uso tridimensionale Tecnologia Inkjet Printing

Bioprinting, which is based on thermal inkjet printing, is one of the most attractive enabling technologies in the field of tissue engineering and ...

Analysis of Cell Migration within a Three-dimensional Collagen Matrix

The ability to migrate is a hallmark of various cell types and plays a crucial role in several physiological processes, including&#160;embryonic development, wound healing, and immune responses. However, cell migration is also a key mechanism in cancer enabling these cancer cells to detach from the primary tumor to start metastatic spreading. Within the past years various cell migration assays have been developed to analyze the migratory behavior of different cell types. Because the locomotory behavior of cells markedly differs between a two-dimensional (2D) and three-dimensional (3D) environment it can be assumed that the analysis of the migration of cells that are embedded within a 3D environment would yield in more significant cell migration data. The advantage of the described 3D collagen matrix migration assay is that cells are embedded within a physiological 3D network of collagen fibers representing the major component of the extracellular matrix. Due to time-lapse video microscopy real cell migration is measured allowing the determination of several migration parameters as well as their alterations in response to pro-migratory factors or inhibitors. Various cell types could be analyzed using this technique, including lymphocytes/leukocytes, stem cells, and tumor cells. Likewise, also cell clusters or spheroids could be embedded within the collagen matrix concomitant with analysis of the emigration of single cells from the cell cluster/ spheroid into the collagen lattice. We conclude that the 3D collagen matrix migration assay is a versatile method to analyze the migration of cells within a physiological-like 3D environment.

Cell migration is a biological phenomenon that is involved in a plethora of physiological, such as wound healing and immune responses, and pathophysiological processes, like cancer. The 3D-collagen matrix migration assay is a versatile tool to analyze the migratory properties of different cell types within in a 3D physiological-like environment.

Analisi della migrazione delle cellule all&#39;interno di una tridimensionale di collagene Matrix

The ability to migrate is a hallmark of various cell types and plays a crucial role in several physiological processes, including&#160;embryonic ...

Generation of a Three-dimensional Full Thickness Skin Equivalent and Automated Wounding

In vitro models are a cost effective and ethical alternative to study cutaneous wound healing processes. Moreover, by using human cells, these models reflect the human wound situation better than animal models. Although two-dimensional models are widely used to investigate processes such as cellular migration and proliferation, models that are more complex are required to gain a deeper knowledge about wound healing. Besides a suitable model system, the generation of precise and reproducible wounds is crucial to ensure comparable results between different test runs. In this study, the generation of a three-dimensional full thickness skin equivalent to study wound healing is shown. The dermal part of the models is comprised of human dermal fibroblast embedded in a rat-tail collagen type I hydrogel. Following the inoculation with human epidermal keratinocytes and consequent culture at the air-liquid interface, a multilayered epidermis is formed on top of the models. To study the wound healing process, we additionally developed an automated wounding device, which generates standardized wounds in a sterile atmosphere.

The goal of this protocol is to build up a three-dimensional full thickness skin equivalent, which resembles natural skin. With a specifically constructed automated wounding device, precise and reproducible wounds can be generated under maintenance of sterility.

Generazione di una tridimensionale a tutto spessore della pelle Equivalent e Automated Ferimento

In vitro models are a cost effective and ethical alternative to study cutaneous wound healing processes. Moreover, by using human cells, these models ...

Preparation and Analysis of In Vitro Three Dimensional Breast Carcinoma Surrogates

Three dimensional (3D) culture is a more physiologically relevant method to model cell behavior in vitro than two dimensional culture. Carcinomas, including breast carcinomas, are complex 3D tissues composed of cancer epithelial cells and stromal components, including fibroblasts and extracellular matrix (ECM). Yet most in vitro models of breast carcinoma consist only of cancer epithelial cells, omitting the stroma and, therefore, the 3D architecture of a tumor in vivo. Appropriate 3D modeling of carcinoma is important for accurate understanding of tumor biology, behavior, and response to therapy. However, the duration of culture and volume of 3D models is limited by the availability of oxygen and nutrients within the culture. Herein, we demonstrate a method in which breast carcinoma epithelial cells and stromal fibroblasts are incorporated into ECM to generate a 3D breast cancer surrogate that includes stroma and can be cultured as a solid 3D structure or by using a perfusion bioreactor system to deliver oxygen and nutrients. Following setup and an initial growth period, surrogates can be used for preclinical drug testing. Alternatively, the cellular and matrix components of the surrogate can be modified to address a variety of biological questions. After culture, surrogates are fixed and processed to paraffin, in a manner similar to the handling of clinical breast carcinoma specimens, for evaluation of parameters of interest. The evaluation of one such parameter, the density of cells present, is explained, where ImageJ and CellProfiler image analysis software systems are applied to photomicrographs of histologic sections of surrogates to quantify the number of nucleated cells per area. This can be used as an indicator of the change in cell number over time or the change in cell number resulting from varying growth conditions and treatments.

Preparation and Analysis of In Vitro Three Dimensional Breast Carcinoma Surrogates

We demonstrate a method to generate 3D breast cancer surrogates, which can be cultured using a perfusion bioreactor system to deliver oxygen and nutrients. Following growth, surrogates are fixed and processed to paraffin for evaluation of parameters of interest. The evaluation of one such parameter, cell density, is explained.

Preparazione e analisi di<em&gt; In Vitro</em&gt; Tridimensionale carcinoma mammario mondo dei replicanti

Three dimensional (3D) culture is a more physiologically relevant method to model cell behavior in vitro than two dimensional culture. Carcinomas, ...

Engineering Three-dimensional Epithelial Tissues Embedded within Extracellular Matrix

The architecture of branched organs such as the lungs, kidneys, and mammary glands arises through the developmental process of branching morphogenesis, which is regulated by a variety of soluble and physical signals in the microenvironment. Described here is a method created to study the process of branching morphogenesis by forming engineered three-dimensional (3D) epithelial tissues of defined shape and size that are completely embedded within an extracellular matrix (ECM). This method enables the formation of arrays of identical tissues and enables the control of a variety of environmental factors, including tissue geometry, spacing, and ECM composition. This method can also be combined with widely used techniques such as traction force microscopy (TFM) to gain more information about the interactions between cells and their surrounding ECM. The protocol can be used to investigate a variety of cell and tissue processes beyond branching morphogenesis, including cancer invasion.

This manuscript describes a soft lithography-based technique to engineer uniform arrays of three-dimensional (3D) epithelial tissues of defined geometry surrounded by extracellular matrix. This method is amenable to a wide variety of cell types and experimental contexts and allows for high-throughput screening of identical replicates.

Tessuti epiteliali Ingegneria tridimensionali integrati all&#39;interno di matrice extracellulare

The architecture of branched organs such as the lungs, kidneys, and mammary glands arises through the developmental process of branching morphogenesis, ...

Culturing Mammalian Cells in Three-dimensional Peptide Scaffolds

A useful technique for culturing cells in a self-assembling nanofiber three-dimensional (3D) scaffold is described. This culture system recreates an environment that closely mimics the structural features of non-polarized tissue. Furthermore, the particular intrinsic nanofiber structure of the scaffold makes it transparent to visual light, which allows for easy visualization of the sample under microscopy. This advantage was largely used to study cell migration, organization, proliferation, and differentiation and thus any development of their particular cellular function by staining with specific dyes or probes. Furthermore, in this work, we describe the good performance of this system to easily study the redifferentiation of expanded human articular chondrocytes into cartilaginous tissue. Cells were encapsulated into self-assembling peptide scaffolds and cultured under specific conditions to promote chondrogenesis. Three-dimensional cultures showed good viability during the 4 weeks of the experiment. As expected, samples cultured with chondrogenic inducers (compared to non-induced controls) stained strongly positive for toluidine blue (which stains glycosaminoglycans (GAGs) that are highly present in cartilage extracellular matrix) and expressed specific molecular markers, including collagen type I, II and X, according to Western Blot analysis. This protocol is easy to perform and can be used at research laboratories, industries and for educational purposes in laboratory courses.

Here, we present a protocol to obtain 3D-culture systems in self-assembling peptide scaffolds to promote the differentiation of dedifferentiated human articular chondrocytes into cartilage-like tissue.

Coltura di cellule di mammifero in scaffold tridimensionale Peptide

A useful technique for culturing cells in a self-assembling nanofiber three-dimensional (3D) scaffold is described. This culture system recreates an ...

Three-dimensional Printing of Thermoplastic Materials to Create Automated Syringe Pumps with Feedback Control for Microfluidic Applications

Microfluidics has become a critical tool in research across the biological, chemical, and physical sciences. One important component of microfluidic experimentation is a stable fluid handling system capable of accurately providing an inlet flow rate or inlet pressure. Here, we have developed a syringe pump system capable of controlling and regulating the inlet fluid pressure delivered to a microfluidic device. This system was designed using low-cost materials and additive manufacturing principles, leveraging three-dimensional (3D) printing of thermoplastic materials and off-the-shelf components whenever possible. This system is composed of three main components: a syringe pump, a pressure transducer, and a programmable microcontroller. Within this paper, we detail a set of protocols for fabricating, assembling, and programming this syringe pump system. Furthermore, we have included representative results that demonstrate high-fidelity, feedback control of inlet pressure using this system. We expect this protocol will allow researchers to fabricate low-cost syringe pump systems, lowering the entry barrier for the use of microfluidics in biomedical, chemical, and materials research.

Here we present a protocol to construct a pressure-controlled syringe pump to be used in microfluidic applications. This syringe pump is made from an&#160;additively manufactured body, off-the-shelf hardware, and open-source electronics. The resulting system is low-cost, straightforward to build, and delivers well-regulated fluid flow to enable rapid microfluidic research.

Tridimensionale di stampa di materiali termoplastici per creare automatizzati pompe a siringa con controllo in retroazione per applicazioni di microfluidica

Microfluidics has become a critical tool in research across the biological, chemical, and physical sciences. One important component of microfluidic ...

Methods Article

Stampa planare e tridimensionale di inchiostri conduttivi