Gli autori desiderano ringraziare l&#39;Università di Akron per il finanziamento che ha sostenuto questo lavoro.

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Ingegneria proteina ricombinante è una tecnica molto potente che abbraccia molte discipline. Si è costo-efficace, regolabile e una procedura relativamente semplice, consentendo la produzione di alte rese di proteine ​​personalizzati. È importante notare che la progettazione ed esprimere proteine ​​bersaglio non è sempre semplice. Espressione basale e la stabilità della proteina ricombinante dipendono da specifiche scelte di vettore, E. coli cellulari, peptide tag aggiunte e parametri colturali. Il ...

Proteine ​​coprono una vasta gamma di biomolecole che sono responsabili di molte funzioni biologiche, portando in definitiva a formazione di tessuto corretto e organizzazione. Queste molecole iniziano migliaia di vie di segnalazione che controllano up-regulation e / o down-regolazione dei geni e delle altre proteine, mantenendo l&#39;equilibrio all&#39;interno del corpo umano. Rottura di una singola proteina colpisce tutta questa rete di segnali, che può portare alla comparsa di disturbi o malattie devastanti. Ingegneria singole proteine ​​in laboratorio offre una soluzione per la lotta contro questi effetti collaterali e offre un&#39;alternativa ai farmaci a piccole molecole. Nel 1977, un gene che codifica la sequenza amminoacidica somatostatina 14 è stato uno dei primi polipeptidi ingegnerizzati creati utilizzando E. coli 1. Poco dopo, nel 1979, l&#39;insulina è stato clonato in plasmide pBR322, trasformato, espresso e purificato 2. Da allora, proteine ​​ricombinanti hanno esteso la loro influenza per più campi di research come biomateriali, drug delivery, l&#39;ingegneria dei tessuti, prodotti biofarmaceutici, agricoltura, enzimi industriali, biocarburanti, ecc (per una rassegna vedi riferimenti 3-8). Ciò è dovuto alla versatilità che la tecnica offre tramite l&#39;aggiunta di applicazioni porzioni chimiche specifiche o sequenze proteiche per scopi che includono, ma non limitato a, l&#39;identificazione delle proteine ​​bersaglio, stabilizzazione e purificazione. Tramite la tecnologia del DNA ricombinante, proteine ​​ricombinanti possono essere espressi in una varietà di sistemi ospite eucariotiche e procariotiche inclusi mammiferi, insetti, piante, lieviti, funghi o batteri. Ogni host offre diversi vantaggi e tipicamente il miglior sistema è determinato sulla base della funzione della proteina, resa, stabilità, costi complessivi e scalabilità. Cellule dei batteri spesso mancano i meccanismi di modificazione post-traslazionale che ospita eucariotiche forniscono (ad esempio la glicosilazione, disolfuro di transizione, e<html> tc.) 5. Di conseguenza, i sistemi di mammiferi e insetti solito risultato migliore compatibilità e l&#39;espressione di proteine ​​eucariotiche, tuttavia questi host sono generalmente più costosi e 9 richiede tempo. Pertanto, E. coli è l&#39;ospite privilegiato per il nostro sistema di espressione perché le cellule si espandono rapidamente in condizioni di crescita economici ed i meccanismi di espressione genetica sono ben compresi 5,9. Inoltre, questo sistema è facile da scalare, per scopi produttivi e dei risultati in proteine ​​funzionali nonostante la mancanza di modificazioni post-traslazionali 10. Il E. coli K12 è scelto in questo protocollo per la clonazione, perché questo ceppo offre ottimi rendimenti plasmide basato su alte efficienze di trasformazione. Inoltre, un E. coli BL21 è utilizzato per l&#39;espressione perché questo ceppo ospite contiene il gene della polimerasi T7 RNA che fornisce l&#39;espressione proteica controllata e stabilità 11. tenda &quot;&gt; Dopo la selezione ospitante, inoltre bisogna fare attenzione nella scelta del vettore di espressione ideale per facilitare l&#39;espressione della proteina selezionata e controllata. Sintetizzando proteine ​​ricombinanti inizia con una sequenza di DNA bersaglio che è clonato sotto la direzione del batteriofago T7 trascrizione e traduzione segnali, e espressione viene indotta in cellule ospiti contenenti copie cromosomiche del gene T7 RNA polimerasi 12. Questi vettori derivati ​​da pBR322 plasmide vettore (per una rassegna vedi riferimento 13), sono strettamente controllato dal promotore T7 sviluppato inizialmente da Studier e colleghi 14 e fornire ulteriori controllo attraverso l&#39;inclusione dell&#39;operatore lac e repressore lac (lac1) 15,16. Per ingegneria proteica ricombinante, questo sistema di espressione offre la possibilità di personalizzare una specifica sequenza amminoacidica di una proteina desiderata inserendo diverse sequenze di DNA bersaglio o per creare proteine ​​di fusione costituiti di dominio combinatos da singole proteine. Inoltre, alcune serie vettore comprendono peptide modifiche tag per essere immessi sul N o C terminus. Per i nostri scopi di progettazione, una istidina (His) tag è stato aggiunto alla sequenza bersaglio di DNA per la purificazione e una sequenza amminoacidica biotinylatable 15 è stato incluso per biotinylation 17,18. In questo protocollo un plasmide contenente un gene di resistenza all&#39;ampicillina, è stato scelto per portare le sequenze di proteine ​​di fusione biotinylatable. Espressione è controllata in questo vettore tramite il T7 promotore lac ed è facilmente indotta con isopropil β-D-1-thiogalactopyranoside (IPTG). Espressioni di prova (colture su piccola scala) vengono utilizzati per determinare la presenza e la solubilità della proteina bersaglio, che può essere espresso sia in una forma solubile o insolubile formulare procedure di purificazione. Una proteina solubile espressa all&#39;interno della cellula batterica subirà pieghevole spontanea di mantenere la sua struttura nativa 19. Tipicamente il nativostruttura è termodinamicamente favorevole. In molti casi l&#39;attività metabolica dell&#39;ospite non è favorevole alla proteina bersaglio, ponendo sollecitazioni al sistema che porta alla produzione di proteine ​​insolubili e la formazione di corpi di inclusione composti di aggregati proteici insolubili. Così la proteina bersaglio denatura, rendendoli generalmente biologicamente inattivo 20. Entrambe le espressioni di prova sono scalati-up, e procedure di isolamento sono determinate dalla solubilità della proteina bersaglio. È necessaria una rinaturazione supplementare o ripiegamento passo per le proteine ​​insolubili. Le proteine ​​ricombinanti risultanti possono essere ulteriormente purificati mediante cromatografia ad esclusione dimensionale. In casa produzione di proteine ​​ricombinanti offre vantaggi economici rispetto ai prodotti commerciali dal milligrammi di proteina bersaglio possono essere isolati per litro di coltura principale. La maggior parte delle attrezzature necessarie è disponibile in un tipico laboratorio biologico o chimico. Ingegneria proteica consente la creazionedi proteine ​​di fusione personalizzato con ulteriori funzionalità che non sempre sono disponibili in commercio. figura 1 illustra i principali procedure necessarie proteine ​​ricombinanti ingegneria. Con questo sistema di espressione abbiamo creato molte proteine ​​biotinylatable, come l&#39;interferone-gamma, fattore di crescita derivato dalle piastrine, e la proteina morfogenetica dell&#39;osso, 21-23, ma ci concentreremo su due proteine ​​che abbiamo progettato per la guida degli assoni, NGF (29 kDa ) e Sema3A (91 kDa) 10 (per una rassegna vedi riferimento 24). Biotinylation è una tecnica comune per l&#39;identificazione, immobilizzazione e l&#39;isolamento di proteine ​​marcate utilizzando il noto interazione biotina-streptavidina 25-27. Sonde biofisiche 28,29, biosensori 30 e 31 punti quantici sono alcuni esempi di sistemi che utilizzano l&#39;alta affinità della biotina-streptavidina coniugazione con una K d dell&#39;ordine di 10 -15 M 27. Il E. bio coliligasi stagno, Bira, aiuti nel legame covalente di biotina alla catena laterale di lisina trovati all&#39;interno della biotina etichettato sequenza di 18,32. Tethering biotina ai materiali e biomolecole ha prodotto la consegna sostenuto di fattori di crescita per cellulare per molteplici applicazioni di ingegneria tissutale 21,33-35. Pertanto, ingegneria queste proteine ​​biotinylatable progettati su misura è un potente strumento che può trascendere molteplici interessi di ricerca.

<table border="0" cellpadding="0" cellspacing="0" width="849">
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		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="20">
			<td height="20" style="height:20px;width:299px;">1,4-dithio--DL-threitol, DTT, 99.5%</td>
			<td style="width:191px;">Chem-Impex International</td>
			<td style="width:121px;">127</td>
			<td style="width:239px;">100 g</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:299px;">2-Hydroxyethylmercaptan &#946;-Mercaptoethanol</td>
			<td>Chem-Impex International</td>
			<td>642</td>
			<td>250 ml</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Acetic acid, glacial</td>
			<td>EMD</td>
			<td>AX0073-9</td>
			<td>2.5 L</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Agar</td>
			<td>Bioshop</td>
			<td>AGR001.500</td>
			<td>500 g</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Ampicillin sodium salt&#160;</td>
			<td>Sigma-Aldrich</td>
			<td>A9518</td>
			<td>25 g</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Antifoam 204</td>
			<td>Sigma-Aldrich</td>
			<td>A6426</td>
			<td>500 g</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Barstar-NGF pET-21a(+)</td>
			<td>GenScript USA Inc.</td>
			<td></td>
			<td>4 &#181;g</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">BL21(DE3) Competent Cells</td>
			<td>Novagen</td>
			<td>69450</td>
			<td>1 ml; Expression Host</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Bradford reagent</td>
			<td>Sigma-Aldrich</td>
			<td>B6916</td>
			<td>500 ml</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">BugBuster</td>
			<td>Novagen</td>
			<td>70922-3</td>
			<td>100 ml</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Gel filtration standard</td>
			<td>Bio-Rad</td>
			<td>151-1901</td>
			<td>6 vials</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Glycerol</td>
			<td>Bioshop</td>
			<td>GLY001.1</td>
			<td>1 L</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:299px;">Guanidine hydrodioride amioformamidine hydrochloride</td>
			<td>Chem-Impex International</td>
			<td>152</td>
			<td>1 kg</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:299px;">His-Pur Ni-NTA Resin</td>
			<td>Thermo Scientific</td>
			<td>88222</td>
			<td>100 ml</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Hydrochloric acid</td>
			<td>EMD&#160;</td>
			<td>HX0603-3</td>
			<td>2.5 L</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Imidazole&#160;</td>
			<td>Chem-Impex International</td>
			<td>418</td>
			<td>250 g</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">IPTG</td>
			<td>Chem-Impex International</td>
			<td>194</td>
			<td>100 g</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Laemmli sample buffer</td>
			<td>Bio-Rad</td>
			<td>161-0737</td>
			<td>30 ml</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:299px;">Lauryl sulfate sodium salt, Sodium dodecyl surface</td>
			<td>Chem-Impex International</td>
			<td>270</td>
			<td>500 g</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">LB Broth&#160;&#160;</td>
			<td>Sigma-Aldrich</td>
			<td>L3022</td>
			<td>1 kg</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">NovaBlue Competent Cells</td>
			<td>Novagen</td>
			<td>69825</td>
			<td>1 ml; Cloning Host</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Phosphate buffered saline</td>
			<td>Sigma-Aldrich</td>
			<td>P5368-10PAK</td>
			<td>10 pack</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Potassium Chloride</td>
			<td>Chem-Impex International</td>
			<td>01247</td>
			<td>1 kg</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Sema3A-pET-21a(+)</td>
			<td>GenScript USA Inc.</td>
			<td></td>
			<td>4 &#181;g</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">SimplyBlue SafeStain</td>
			<td>Invitrogen</td>
			<td>LC6060</td>
			<td>1 L</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Sodium chloride</td>
			<td>Sigma-Aldrich</td>
			<td>S5886-1KG</td>
			<td>1 kg</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Sodium hydroxide</td>
			<td>Fisher Scientific</td>
			<td>S318-500</td>
			<td>500 g</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Sodium phosphate diabasic</td>
			<td>Sigma-Aldrich</td>
			<td>S5136-500G</td>
			<td>500 g</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Sodium phosphate monobasic</td>
			<td>Sigma-Aldrich</td>
			<td>S5011</td>
			<td>500 g</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Terrific Broth</td>
			<td>Bioshop</td>
			<td>TER409.5</td>
			<td>5 kg</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Tetracycline hydrochloride</td>
			<td>Chem-Impex International</td>
			<td>667</td>
			<td>25 g</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Tris/Glycine/SDS Buffer, 10X</td>
			<td>Bio-Rad</td>
			<td>1610732</td>
			<td>1 L</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Trizma Base</td>
			<td>Sigma-Aldrich</td>
			<td>T1503</td>
			<td>1 kg</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Tryptone, pancreatic</td>
			<td>EMD</td>
			<td>1.07213.1000</td>
			<td>1 kg</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Yeast extract, granulated</td>
			<td>EMD</td>
			<td>1.03753.0500</td>
			<td>500 g</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;"></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr height="56">
			<td height="56" style="height:56px;width:299px;">Name of Kits/ Equipment</td>
			<td style="width:191px;">Company</td>
			<td style="width:121px;">Catalog Number</td>
			<td>Comments/Description</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:299px;">&#160;&#196;KTApurifier10</td>
			<td style="width:191px;">GE Healthcare</td>
			<td style="width:121px;">28-4062-64&#160;</td>
			<td>Includes kits and accessories</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:299px;">Benchtop Orbital Shaker</td>
			<td style="width:191px;">Thermo Scientific</td>
			<td style="width:121px;">SHKE4000</td>
			<td>MAXQ 4000</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:299px;">BirA500</td>
			<td style="width:191px;">Avidity</td>
			<td style="width:121px;">BirA500</td>
			<td style="width:239px;">Enzyme comes with reaction buffers and biotin solution</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:299px;">Dialysis Casette</td>
			<td style="width:191px;">Thermo Scientific</td>
			<td style="width:121px;">66380</td>
			<td>Slide-A-Lyzer (Extra Strength)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:299px;">Dialysis Tubing</td>
			<td style="width:191px;">Spectrum Laboratories&#160;</td>
			<td style="width:121px;">132127, 132129</td>
			<td style="width:239px;">MWCO: 25,000 and 50,000</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:299px;">Flow Diversion Valve FV-923</td>
			<td style="width:191px;">GE Healthcare</td>
			<td style="width:121px;">11-0011-70</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:299px;">FluoReporter Biotin Quantification Assay Kit</td>
			<td style="width:191px;">Invitrogen</td>
			<td style="width:121px;">1094598</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:299px;">Frac-950 Tube Racks, Rack C</td>
			<td style="width:191px;">GE Healthcare</td>
			<td style="width:121px;">18-6083-13</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:299px;">Fraction Collector Frac-950</td>
			<td style="width:191px;">GE Healthcare</td>
			<td style="width:121px;">18-6083-00</td>
			<td>Includes kits and accessories</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:299px;">Heated/Refrigerated Circulator&#160;</td>
			<td style="width:191px;">VWR</td>
			<td style="width:121px;">13271-102</td>
			<td>Model 1156D</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:299px;">Heating Oven FD Series</td>
			<td style="width:191px;">Binder</td>
			<td style="width:121px;"></td>
			<td>Model FD 115</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;">HiLoad 16/60 Superdex 200 pg</td>
			<td style="width:191px;">GE Healthcare</td>
			<td style="width:121px;">17-1069-01</td>
			<td style="width:239px;">Discontinued--Replacement Product: HiLoad 16/600 Superdex 200 pg</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:299px;">J-26 XPI Avanti Centrifuge</td>
			<td style="width:191px;">Beckman Coulter</td>
			<td style="width:121px;">393126</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:299px;">JA 25.50 Rotor</td>
			<td style="width:191px;">Beckman Coulter</td>
			<td style="width:121px;">363055</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:299px;">JLA 8.1 Rotor</td>
			<td style="width:191px;">Beckman Coulter</td>
			<td style="width:121px;">969329</td>
			<td>Includes 1 L polyporpylene bottles</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:299px;">JS 5.3 Rotor</td>
			<td style="width:191px;">Beckman Coulter</td>
			<td style="width:121px;">368690</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:299px;">Laminar Flow Hood</td>
			<td style="width:191px;">Themo Scientific</td>
			<td style="width:121px;">1849</td>
			<td style="width:239px;">Forma 1800 Series Clean Bench</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:299px;">Microplate Reader</td>
			<td style="width:191px;">TECAN</td>
			<td style="width:121px;"></td>
			<td>infinite M200</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:299px;">Mini-PROTEAN Tetra Cell</td>
			<td style="width:191px;">Bio-Rad</td>
			<td style="width:121px;">165-8004</td>
			<td style="width:239px;">4-gel vertical electrophoresis system</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:299px;">Mini-PROTEAN TGX Precast Gels</td>
			<td style="width:191px;">Bio-Rad</td>
			<td style="width:121px;">456-9036</td>
			<td style="width:239px;">Any kDa, 15-well comb</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:299px;">Ni-NTA Column</td>
			<td>Bio-Rad</td>
			<td>737-2512</td>
			<td>49 ml&#160;volume ECONO-Column</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:299px;">Plasmid Miniprep Kit</td>
			<td style="width:191px;">OMEGA bio-tek</td>
			<td style="width:121px;">D6943-01</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:299px;">PowerPac HC Power Supply</td>
			<td>Bio-Rad</td>
			<td style="width:121px;">164-5052</td>
			<td>250 V, 3 A, 300 W</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:299px;">Round Bottom Polypropylene Copolymer Tubes</td>
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			<td style="width:121px;">3119-0050</td>
			<td>50 ml&#160;tubes for JA 25.50 rotor</td>
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			<td height="21" style="height:21px;width:299px;">Spin-X UF Concentrators</td>
			<td style="width:191px;">Corning</td>
			<td style="width:121px;">431488, 431483</td>
			<td>&#160;20 and 6 ml; MWCO: 10,000 Da</td>
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		<tr height="21">
			<td height="21" style="height:21px;width:299px;">Subcloning Service</td>
			<td style="width:191px;">GenScript USA Inc.</td>
			<td style="width:121px;"></td>
			<td>Protein Services</td>
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			<td height="21" style="height:21px;width:299px;">Ultrasonic Processor&#160;</td>
			<td style="width:191px;">Cole-Parmer</td>
			<td style="width:121px;">18910445A</td>
			<td>Model CV18</td>
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		<tr height="21">
			<td height="21" style="height:21px;width:299px;">Vortex-Genie 2</td>
			<td style="width:191px;">Scientific Industries</td>
			<td>SI-0236</td>
			<td>Model G560</td>
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expression, isolation, and purification of soluble and insoluble biotinylated proteins for nerve tissue regeneration

Ingegneria proteica ricombinante ha utilizzato Escherichia coli (E. coli) sistemi di espressione per quasi 4 decenni, e oggi E. coli è ancora dell&#39;organismo ospite più utilizzato. La flessibilità del sistema consente l&#39;aggiunta di frazioni come per esempio un tag biotina (per interazioni streptavidina) e proteine ​​funzionali più grandi come proteina fluorescente verde o ciliegio proteina rosso. Inoltre, l&#39;integrazione di amminoacidi innaturali come chelanti di ioni metallici, gruppi funzionali reattivi univoco, sonde spettroscopiche, e molecole che impartiscono modificazioni post-traduzionali ha permesso una migliore manipolazione delle proprietà proteiche e funzionalità. Di conseguenza questa tecnica crea proteine ​​di fusione personalizzabili che offrono utilità significativa per vari campi di ricerca. Più specificamente, la sequenza proteica biotinylatable è stato incorporato in molte proteine ​​bersaglio a causa della elevata interazione affinità tra biotina con avidina e streptavidina. Questa aggiunta ha aiutato a migliorare la rilevazione e purificazione di proteine ​​nella categoria oltre ad aprire la strada ad applicazioni secondarie, come l&#39;ordinamento delle cellule. Così, molecole di biotina marcata mostrano una crescente influenza e diffusa nei campi bioindustriale e biomedica. Ai fini della nostra ricerca abbiamo ingegnerizzato proteine ​​di fusione biotinilato ricombinanti contenenti il ​​fattore di crescita nervoso (NGF) e semaphorin3A (Sema3A) regioni funzionali. Abbiamo precedentemente riportato come queste proteine ​​di fusione biotinilato, insieme ad altre sequenze proteiche attive, possono essere legati a biomateriali per l&#39;ingegneria tissutale e scopi rigenerativi. Questo protocollo delinea le basi delle proteine ​​ingegneria biotinylatable alla scala milligrammo, utilizzando un T7 lac inducibile vettoriale e E. padroni di espressione coli, a partire da trasformazione di scale-up e di purificazione.

<html> Cloning and Test Expression Quando placcatura viene eseguita correttamente, singole colonie isolate dovrebbero costituire per aumentare le possibilità di spennare clonale trasformati batteri cellule (Figura 2A). Tuttavia, se troppe cellule vengono piastrate, piastre vengono incubate troppo tempo a 37 ° C o trasformazione è discutibile, le colonie possono coprire la piastra di agar o formare grandi aggregati di cellule (figure 2b e <...

Watch this Scientific Journal Video about Expression, Isolation, and Purification of Soluble and Insoluble Biotinylated Proteins for Nerve Tissue Regeneration at JoVE.com

Expression, Isolation, and Purification of Soluble and Insoluble Biotinylated Proteins for Nerve Tissue Regeneration

Sviluppo di proteine ​​di fusione biotinylatable ha molte potenziali applicazioni in diversi campi di ricerca. Ingegneria proteina ricombinante è una procedura dritto in avanti che è costo-efficace, che fornisce alte rese di proteine ​​personalizzati.

Espressione, isolamento e purificazione di solubili e insolubili Biotinylated proteine ​​per Nerve Tissue Regeneration

Recombinant protein engineering has utilized Escherichia coli (E. coli) expression systems for nearly 4 decades, and today E. coli is still the most ...

expression-isolation-purification-soluble-insoluble-biotinylated

Research

JoVE Journal

Bioengineering

33.4K Views.  University of Akron.  Sviluppo di proteine ​​di fusione biotinylatable ha molte potenziali applicazioni in diversi campi di ricerca. Ingegneria proteina ricombinante è una procedura dritto in avanti che è costo-efficace, che fornisce alte rese di proteine ​​personalizzati. 

Video: Expression, Isolation, and Purification of Soluble and Insoluble Biotinylated Proteins for Nerve Tissue Regeneration

Use of Human Perivascular Stem Cells for Bone Regeneration

Human perivascular stem cells (PSCs) can be isolated in sufficient numbers from multiple tissues for purposes of skeletal tissue engineering1-3. PSCs are a FACS-sorted population of 'pericytes' (CD146+CD34-CD45-) and 'adventitial cells' (CD146-CD34+CD45-), each of which we have previously reported to have properties of mesenchymal stem cells. PSCs, like MSCs, are able to undergo osteogenic differentiation, as well as secrete pro-osteogenic cytokines1,2. In the present protocol, we demonstrate the osteogenicity of PSCs in several animal models including a muscle pouch implantation in SCID (severe combined immunodeficient) mice, a SCID mouse calvarial defect and a femoral segmental defect (FSD) in athymic rats. The thigh muscle pouch model is used to assess ectopic bone formation. Calvarial defects are centered on the parietal bone and are standardly 4 mm in diameter (critically sized)8. FSDs are bicortical and are stabilized with a polyethylene bar and K-wires4. The FSD described is also a critical size defect, which does not significantly heal on its own4. In contrast, if stem cells or growth factors are added to the defect site, significant bone regeneration can be appreciated. The overall goal of PSC xenografting is to demonstrate the osteogenic capability of this cell type in both ectopic and orthotopic bone regeneration models.

Human perivascular stem cells (PSCs) are a novel stem cell class for skeletal tissue regeneration similar to mesenchymal stem cells (MSCs). PSCs can be isolated by FACS (fluorescence activated cell sorting) from adipose tissue procured during standard liposuction procedures, then combined with an osteoinductive scaffold to achieve bone formation in vivo.

L&#39;uso di cellule staminali per la rigenerazione ossea perivascolari

Human perivascular stem cells (PSCs) can be isolated in sufficient numbers from multiple tissues for purposes of skeletal tissue engineering1-3. PSCs are ...

Ricerca

Bioingegneria

Non-contact, Label-free Monitoring of Cells and Extracellular Matrix using Raman Spectroscopy

Non-destructive, non-contact and label-free technologies to monitor cell and tissue cultures are needed in the field of biomedical research.1-5 However, currently available routine methods require processing steps and alter sample integrity. Raman spectroscopy is a fast method that enables the measurement of biological samples without the need for further processing steps. This laser-based technology detects the inelastic scattering of monochromatic light.6 As every chemical vibration is assigned to a specific Raman band (wavenumber in cm-1), each biological sample features a typical spectral pattern due to their inherent biochemical composition.7-9 Within Raman spectra, the peak intensities correlate with the amount of the present molecular bonds.1 Similarities and differences of the spectral data sets can be detected by employing a multivariate analysis (e.g. principal component analysis (PCA)).10
Here, we perform Raman spectroscopy of living cells and native tissues. Cells are either seeded on glass bottom dishes or kept in suspension under normal cell culture conditions (37 &deg;C, 5% CO2) before measurement. Native tissues are dissected and stored in phosphate buffered saline (PBS) at 4 &deg;C prior measurements. Depending on our experimental set up, we then either focused on the cell nucleus or extracellular matrix (ECM) proteins such as elastin and collagen. For all studies, a minimum of 30 cells or 30 random points of interest within the ECM are measured. Data processing steps included background subtraction and normalization.

Raman spectroscopy is a suitable technique for the non-contact, label-free analysis of living cells, tissue-engineered constructs and native tissues. Source-specific spectral fingerprints can be generated and analyzed using multivariate analysis.

Senza contatto, Label-free monitoraggio delle cellule e matrice extracellulare mediante Spettroscopia Raman

Non-destructive, non-contact and label-free technologies to monitor cell and tissue cultures are needed in the field of biomedical research.1-5 However, ...

Creating Adhesive and Soluble Gradients for Imaging Cell Migration with Fluorescence Microscopy

Cells can sense and migrate towards higher concentrations of adhesive cues such as the glycoproteins of the extracellular matrix and soluble cues such as growth factors. Here, we outline a method to create opposing gradients of adhesive and soluble cues in a microfluidic chamber, which is compatible with live cell imaging. A copolymer of poly-L-lysine and polyethylene glycol (PLL-PEG) is employed to passivate glass coverslips and prevent non-specific adsorption of biomolecules and cells. Next, microcontact printing or dip pen lithography are used to create tracks of streptavidin on the passivated surfaces to serve as anchoring points for the biotinylated peptide arginine-glycine-aspartic acid (RGD) as the adhesive cue. A microfluidic device is placed onto the modified surface and used to create the gradient of adhesive cues (100% RGD to 0% RGD) on the streptavidin tracks. Finally, the same microfluidic device is used to create a gradient of a chemoattractant such as fetal bovine serum (FBS), as the soluble cue in the opposite direction of the gradient of adhesive cues.

A method for the assembly of adhesive and soluble gradients in a microscopy chamber for live cell migration studies is described. The engineered environment combines antifouling surfaces and adhesive tracks with solution gradients and therefore allows one to determine the relative importance of guidance cues.

Creazione di sfumature adesivi e solubile per la migrazione di imaging cellulare con microscopia a fluorescenza

Cells can sense and migrate towards higher concentrations of adhesive cues such as the glycoproteins of the extracellular matrix and soluble cues such as ...

Engineering 3D Cellularized Collagen Gels for Vascular Tissue Regeneration

Synthetic materials are known to initiate clinical complications such as inflammation, stenosis, and infections when implanted as vascular substitutes. Collagen has been extensively used for a wide range of biomedical applications and is considered a valid alternative to synthetic materials due to its inherent biocompatibility (i.e., low antigenicity, inflammation, and cytotoxic responses). However, the limited mechanical properties and the related low hand-ability of collagen gels have hampered their use as scaffold materials for vascular tissue engineering. Therefore, the rationale behind this work was first to engineer cellularized collagen gels into a tubular-shaped geometry and second to enhance smooth muscle cells driven reorganization of collagen matrix to obtain tissues stiff enough to be handled.
The strategy described here is based on the direct assembling of collagen and smooth muscle cells (construct) in a 3D cylindrical geometry with the use of a molding technique. This process requires a maturation period, during which the constructs are cultured in a bioreactor under static conditions (without applied external dynamic mechanical constraints) for 1 or 2 weeks. The &#8220;static bioreactor&#8221; provides a monitored and controlled sterile environment (pH, temperature, gas exchange, nutrient supply and waste removal) to the constructs. During culture period, thickness measurements were performed to evaluate the cells-driven remodeling of the collagen matrix, and glucose consumption and lactate production rates were measured to monitor the cells metabolic activity. Finally, mechanical and viscoelastic properties were assessed for the resulting tubular constructs. To this end, specific protocols and a focused know-how (manipulation, gripping, working in hydrated environment, and so on) were developed to characterize the engineered tissues.

In this work, we present a technique for the rapid fabrication of living vascular tissues by direct culturing of collagen, smooth muscle cells and endothelial cells. In addition, a new protocol for the mechanical characterization of engineered vascular tissues is described.

Ingegneria 3D Cellularized collagene Gel per Vascolare Rigenerazione Tissutale

Synthetic materials are known to initiate clinical complications such as inflammation, stenosis, and infections when implanted as vascular substitutes. ...

Design and Construction of Artificial Extracellular Matrix (aECM) Proteins from Escherichia coli for Skin Tissue Engineering

Recombinant technology is a versatile platform to create novel artificial proteins with tunable properties. For the last decade, many artificial proteins that have incorporated functional domains derived from nature (or created de novo) have been reported. In particular, artificial extracellular matrix (aECM) proteins have been developed; these aECM proteins consist of biological domains taken from fibronectin, laminins and collagens and are combined with structural domains including elastin-like repeats, silk and collagen repeats. To date, aECM proteins have been widely investigated for applications in tissue engineering and wound repair. Recently, Tjin and coworkers developed integrin-specific aECM proteins designed for promoting human skin keratinocyte attachment and propagation. In their work, the aECM proteins incorporate cell binding domains taken from fibronectin, laminin-5 and collagen IV, as well as flanking elastin-like repeats. They demonstrated that the aECM proteins developed in their work were promising candidates for use as substrates in artificial skin. Here, we outline the design and construction of such aECM proteins as well as their purification process using the thermo-responsive characteristics of elastin.

Design and Construction of Artificial Extracellular Matrix aECM Proteins from Escherichia coli for Skin Tissue Engineering

Recombinant technologies have enabled material designers to create novel artificial proteins with customized functionalities for tissue engineering applications. For example, artificial extracellular matrix proteins can be designed to incorporate structural and biological domains derived from native ECMs. Here, we describe the construction and purification of aECM proteins containing elastin-like repeats.

Progettazione e Costruzione di Artificiale matrice extracellulare (AECM) Proteine ​​da<em&gt; Escherichia coli</em&gt; Per la pelle Ingegneria dei Tessuti

Recombinant technology is a versatile platform to create novel artificial proteins with tunable properties. For the last decade, many artificial proteins ...

A Microfluidic Platform for High-throughput Single-cell Isolation and Culture

Studying the heterogeneity of single cells is crucial for many biological questions, but is technically difficult. Thus, there is a need for a simple, yet high-throughput, method to perform single-cell culture experiments. Here, we report a microfluidic chip-based strategy for high-efficiency single-cell isolation (~77%) and demonstrate its capability of performing long-term single-cell culture (up to 7 d) and cellular heterogeneity analysis using clonogenic assay. These applications were demonstrated with KT98 mouse neural stem cells, and A549 and MDA-MB-435 human cancer cells. High single-cell isolation efficiency and long-term culture capability are achieved by using different sizes of microwells on the top and bottom of the microfluidic channel. The small microwell array is designed for precisely isolating single-cells, and the large microwell array is used for single-cell clonal culture in the microfluidic chip. This microfluidic platform constitutes an attractive approach for single-cell culture applications, due to its flexibility of adjustable cell culture spaces for different culture strategies, without decreasing isolation efficiency.

Here, we present a protocol for isolating and culturing single cells with a microfluidic platform, which utilizes a new microwell design concept to allow for high-efficiency single cell isolation and long-term clonal culture.

Una piattaforma Microfluidic per l&#39;isolamento Single-cell high-throughput e cultura

Studying the heterogeneity of single cells is crucial for many biological questions, but is technically difficult. Thus, there is a need for a simple, yet ...

Isolation of Murine Adipose Tissue-derived Microvascular Fragments as Vascularization Units for Tissue Engineering

A functional microvascular network is of pivotal importance for the survival and integration of engineered tissue constructs. For this purpose, several angiogenic and prevascularization strategies have been established. However, most cell-based approaches include time-consuming in vitro steps for the formation of a microvascular network. Hence, they are not suitable for intraoperative one-step procedures. Adipose tissue-derived microvascular fragments (ad-MVF) represent promising vascularization units. They can be easily isolated from fat tissue and exhibit a functional microvessel morphology. Moreover, they rapidly reassemble into new microvascular networks after in vivo implantation. In addition, ad-MVF have been shown to induce lymphangiogenesis. Finally, they are a rich source of mesenchymal stem cells, which may further contribute to their high vascularization potential. In previous studies we have demonstrated the remarkable vascularization capacity of ad-MVF in engineered bone and skin substitutes. In the present study, we report on a standardized protocol for the enzymatic isolation of ad-MVF from murine fat tissue.

We present a protocol to isolate adipose tissue-derived microvascular fragments that represent promising vascularization units. They can be rapidly isolated, do not require in vitro processing and, thus, may be used for one-step prevascularization in different fields of tissue engineering.

L&#39;isolamento di Murine adiposo derivate dal tessuto microvascolare Frammenti come vascolarizzazione Unità per Tissue Engineering

A functional microvascular network is of pivotal importance for the survival and integration of engineered tissue constructs. For this purpose, several ...

Three-dimensional Tissue Engineered Aligned Astrocyte Networks to Recapitulate Developmental Mechanisms and Facilitate Nervous System Regeneration

Neurotrauma and neurodegenerative disease often result in lasting neurological deficits due to the limited capacity of the central nervous system (CNS) to replace lost neurons and regenerate axonal pathways. However, during nervous system development, neuronal migration and axonal extension often occur along pathways formed by other cells, referred to as &#34;living scaffolds&#34;. Seeking to emulate these mechanisms and to design a strategy that circumvents the inhibitory environment of the CNS, this manuscript presents a protocol to fabricate tissue engineered astrocyte-based &#34;living scaffolds&#34;. To create these constructs, we employed a novel biomaterial encasement scheme to induce astrocytes to self-assemble into dense three-dimensional bundles of bipolar longitudinally-aligned somata and processes. First, hollow hydrogel micro-columns were assembled, and the inner lumen was coated with collagen extracellular-matrix. Dissociated cerebral cortical astrocytes were then delivered into the lumen of the cylindrical micro-column and, at a critical inner diameter of &#60;350 &#181;m, spontaneously self-aligned and contracted to produce long fiber-like cables consisting of dense bundles of astrocyte processes and collagen fibrils measuring &#60;150 &#181;m in diameter yet extending several cm in length. These engineered living scaffolds exhibited &#62;97% cell viability and were virtually exclusively comprised of astrocytes expressing a combination of the intermediate filament proteins glial-fibrillary acidic protein (GFAP), vimentin, and nestin. These aligned astrocyte networks were found to provide a permissive substrate for neuronal attachment and aligned neurite extension. Moreover, these constructs maintain integrity and alignment when extracted from the hydrogel encasement, making them suitable for CNS implantation. These preformed constructs structurally emulate key cytoarchitectural elements of naturally occurring glial-based &#34;living scaffolds&#34; in vivo. As such, these engineered living scaffolds may serve as test-beds to study neurodevelopmental mechanisms in vitro or facilitate neuroregeneration by directing neuronal migration and/or axonal pathfinding following CNS degeneration in vivo.

We showcase the development of self-assembled, three-dimensional bundles of longitudinally aligned astrocytic somata and processes within a novel biomaterial encasement. These engineered &#34;living scaffolds&#34;, exhibiting micron-scale diameter yet extending centimeters in length, may serve as test-beds to study neurodevelopmental mechanisms or facilitate neuroregeneration by directing neuronal migration and/or axonal pathfinding.

Tessutale tridimensionale allineato Astrocyte reti per ricapitolare i meccanismi dello sviluppo e facilitare la rigenerazione del sistema nervoso

Neurotrauma and neurodegenerative disease often result in lasting neurological deficits due to the limited capacity of the central nervous system (CNS) to ...

Isolation of Mesenchymal Stem Cells from Human Alveolar Periosteum and Effects of Vitamin D on Osteogenic Activity of Periosteum-derived Cells

Mesenchymal stem cells (MSCs) are present in a variety of tissues and can be differentiated into numerous cell types, including osteoblasts. Among the dental sources of MSCs, the periosteum is an easily accessible tissue, which has been identified to contain MSCs in the cambium layer. However, this source has not yet been widely studied.
Vitamin D3 and 1,25-(OH)2D3 have been demonstrated to stimulate in vitro differentiation of MSCs into osteoblasts. In addition, vitamin C facilitates collagen formation and bone cell growth. However, no study has yet investigated the effects of Vitamin D3 and Vitamin C on MSCs.
Here, we present a method of isolating MSCs from human alveolar periosteum and examine the hypothesis that 1,25-(OH)2D3 may exert an osteoinductive effect on these cells. We also investigate the presence of MSCs in the human alveolar periosteum and assess stem cell adhesion and proliferation. To assess the ability of vitamin C (as a control) and various concentrations of 1,25-(OH)2D3 (10&#8722;10, 10&#8722;9, 10&#8722;8, and 10&#8722;7 M) to alter key mRNA biomarkers in isolated MSCs mRNA expression of alkaline phosphatase (ALP), bone sialoprotein (BSP), core binding factor alpha-1 (CBFA1), collagen-1, and osteocalcin (OCN) are measured using real-time polymerase chain reaction (RT-PCR).

We present a protocol to investigate the mRNA expression biomarkers of periosteum-derived cells (PDCs) induced by vitamin C (vitamin C) and 1,25-dihydroxy vitamin D [1,25-(OH)2D3]. In addition, we evaluate the ability of PDCs to differentiate into osteocytes, chondrocytes, and adipocytes.

Isolamento di cellule staminali mesenchimali da periostio alveolare umano e gli effetti della vitamina D su attività osteogenica delle cellule derivate dal periostio

Mesenchymal stem cells (MSCs) are present in a variety of tissues and can be differentiated into numerous cell types, including osteoblasts. Among the ...

Wet-spinning-based Molding Process of Gelatin for Tissue Regeneration

This article presents an inexpensive method to fabricate gelatin, as a natural polymer, into monofilament fibers or other appropriate forms. Through the wet spinning method, gelatin fibers are produced by smooth extrusion in a suitable coagulation medium. To increase the functional surface of these gelatin fibers and their ability to mimic the features of tissues, gelatin can be molded into a tube form by referring to this concept. Examined by in vitro and in vivo tests, the gelatin tubes demonstrate a great potential for application in tissue engineering. Acting as a suitable filling gap material, gelatin tubes can be used to substitute the tissue in the damaged area (e.g., in the nervous or cardiovascular system), as well as to promote regeneration by providing a direct replacement of stem cells and neural circuitry. This protocol provides a detailed procedure for creating a biomaterial based on a natural polymer, and its implementation is expected to greatly benefit the development of correlative natural polymers, which help to realize tissue regeneration strategies.

We developed and describe a protocol based on the wet spinning concept, for the construction of gelatin-based biomaterials used for the application of tissue engineering.

Processo di stampaggio basati su bagnato-filatura di gelatina per la rigenerazione tissutale

This article presents an inexpensive method to fabricate gelatin, as a natural polymer, into monofilament fibers or other appropriate forms. Through the ...

Espressione, isolamento e purificazione di solubili e insolubili Biotinylated proteine ​​per Nerve Tissue Regeneration

Espressione, isolamento e purificazione di solubili e insolubili Biotinylated proteine per Nerve Tissue Regeneration