multi-scale-modification-metallic-implants-with-pore-gradients

Multi-Scale Modification of Metallic Implants With Pore Gradients, Polyelectrolytes and Their Indirect Monitoring <em>In vivo</em>

Metallic implants, especially titanium implants, are widely used in  clinical applications. Tissue in-growth and integration to these implants in  the ...

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Collagen-based micropatterned films were seeded with human corneal keratocyte and epithelial cells to study their mechanical properties as tissue engineering substrates. The patterns were in the form of parallel channels with slanted walls. Influence of cell presence, type and growth on the mechanical properties of the films was investigated. Unseeded films showed gradual strength reduction from an initial value of 0.046 N/mm, possibly due to degradation, down to 0.032+/-0.012 N/mm in 2 weeks. Keratocyte growth was found to significantly improve the mechanical behavior of the films upon 1 week of incubation (0.067+/-0.017 N/mm) and the improvement continued gradually over the next 2 weeks. Films seeded with D407 retinal pigment epithelial cells, on the other hand, experienced a decrease (0.023+/-0.011 N/mm), followed by a slight increase in mechanical properties in the 21-day period. A steady increase in the number of keratocytes along the channels, cytoskeleton alignment and extracellular matrix (ECM) secretion restricted to the channels was observed. Increase in strength observed with keratocytes and, to a lesser extent, with the epithelial cells can be attributed to directional ECM synthesis and the orientation of the cells and their cytoskeleton which contribute to the strength in the direction of the channels. This study showed that cell, especially keratocyte, presence compensates for the degradation of collagen films and improve the overall mechanical properties of the engineered tissue.

Effect of human corneal keratocytes and retinal pigment epithelial cells on the mechanical properties of micropatterned collagen films.

Films MICROIMPRIMEES &agrave; base de collag&egrave;ne ont &eacute;t&eacute; ensemenc&eacute;es avec keratocyte corn&eacute;en humain et les cellules &eacute;pith&eacute;liales d&#39;&eacute;tudier leurs propri&eacute;t&eacute;s m&eacute;caniques comme substrats en g&eacute;nie tissulaire. Les patrons &eacute;taient sous forme de canaux parall&egrave;les aux murs inclin&eacute;s. Influence de la pr&eacute;sence de cellules, de type et de la croissance sur les propri&eacute;t&eacute;s m&eacute;caniques des films a &eacute;t&eacute; &eacute;tudi&eacute;e. Films non ensemenc&eacute;es a montr&eacute; la r&eacute;duction graduelle de la force d&#39;une valeur initiale de 0,046 N/mm, peut-&ecirc;tre en raison de la d&eacute;gradation, vers le bas pour 0.032+/-0.012 N/mm en 2 semaines. Keratocyte la croissance s&#39;est av&eacute;r&eacute;e pour am&eacute;liorer de fa&ccedil;on significative le comportement m&eacute;canique des films apr&egrave;s 1 semaine d&#39;incubation (0,067 +/-0.017 N/mm) et de l&#39;am&eacute;lioration continue progressivement au cours des 2 prochaines semaines. Films ensemenc&eacute;es avec des cellules &eacute;pith&eacute;liales du pigment r&eacute;tinien D407, en revanche, a connu une diminution (0,023 &plusmn; 0,011 N/mm), suivie d&#39;une l&eacute;g&egrave;re augmentation des propri&eacute;t&eacute;s m&eacute;caniques dans la p&eacute;riode de 21 jours. Une augmentation constante du nombre des keratocytes sur les canaux, l&#39;alignement du cytosquelette et la s&eacute;cr&eacute;tion de matrice extracellulaire (ECM) restreint aux canaux a &eacute;t&eacute; observ&eacute;e. Augmentation des effectifs observ&eacute;s avec keratocytes et, dans une moindre mesure, avec les cellules &eacute;pith&eacute;liales peut &ecirc;tre attribu&eacute;e &agrave; la synth&egrave;se d&#39;ECM directionnelle et l&#39;orientation des cellules et leur cytosquelette qui contribuent &agrave; la force dans la direction des canaux. Cette &eacute;tude a montr&eacute; que la cellule, en particulier keratocyte, pr&eacute;sence compense la d&eacute;gradation des films de collag&egrave;ne et d&#39;am&eacute;liorer les propri&eacute;t&eacute;s m&eacute;caniques dans l&#39;ensemble de l&#39;ing&eacute;nierie tissulaire.

Effet des keratocytes corn&eacute;en humain et les cellules &eacute;pith&eacute;liales pigmentaire sur les propri&eacute;t&eacute;s m&eacute;caniques des films de collag&egrave;ne micromotifs.

Film a base di collagene micropatterned sono stati seminati con cheratinociti corneale umano e cellule epiteliali per studiare le loro propriet&agrave; meccaniche come substrati di ingegneria dei tessuti. I modelli erano in forma di canali paralleli con pareti inclinate. Influenza della crescita sulle propriet&agrave; meccaniche dei film, tipo e presenza di cellule &egrave; stato studiato. Testa di serie film hanno mostrato riduzione graduale forza da un valore iniziale di 0,046 N/mm, probabilmente a causa di degrado, fino a 0.032+/-0.012 N/mm in 2 settimane. Crescita di cheratinociti &egrave; stato trovato per migliorare significativamente il comportamento meccanico dei film su 1 settimana di incubazione (0.067 + /-0,017 N/mm) e il miglioramento continuata gradualmente nelle prossime 2 settimane. Film seminato con cellule epiteliali del pigmento retinico D407, d&#39;altra parte, ha sperimentato una diminuzione (0,023 + 0,011 N/mm), seguita da un lieve aumento nella propriet&agrave; meccaniche nel periodo di 21 giorni. &Egrave; stato osservato un costante aumento del numero di cheratociti lungo i canali, allineamento del citoscheletro e secrezione di matrice extracellulare (ECM) limitato ai canali. Aumento della resistenza osservata con cheratociti e, in misura minore, con le cellule epiteliali pu&ograve; essere attribuita a direzionale ECM sintesi e l&#39;orientamento delle cellule e loro citoscheletro che contribuiscono alla resistenza in direzione dei canali. Questo studio ha mostrato che la cella, soprattutto regolarizza, presenza compensa la degradazione delle pellicole di collagene e migliorare le propriet&agrave; meccaniche in generale del tessuto ingegnerizzato.

Effetto di cheratociti corneali umano e cellule epiteliali del pigmento retinico sulle propriet&agrave; meccaniche dei film di collagene micropatterned.

It is desirable to produce cryopreservable cell-laden tissue-engineering scaffolds whose final properties can be adjusted during the thawing process immediately prior to use. Polyvinyl alcohol (PVA)-based solutions provide platforms in which cryoprotected cell suspensions can be turned into a ready-to-use, cell-laden scaffold by a process of cryogelation. In this study, such a PVA system, with DMSO as the cryoprotectant, was successfully developed. Vascular smooth muscle cell (vSMC)-encapsulated cryogels were investigated under conditions of cyclic strain and in co-culture with vascular endothelial cells to mimic the environment these cells experience in vivo in a vascular tissue-engineering setting. In view of the cytotoxicity DMSO imposes with respect to the production procedure, carboxylated poly-L-lysine (COOH-PLL) was substituted as a non-cytotoxic cryoprotectant to allow longer, slower thawing periods to generate more stable cryogels. Encapsulated vSMC with DMSO as a cryoprotectant responded to 10% cyclic strain with increased alignment and proliferation. Cells were stored frozen for 1 month without loss of viability compared to immediate thawing. SMC-encapsulated cryogels also successfully supported functional endothelial cell co-culture. Substitution of COOH-PLL in place of DMSO resulted in a significant increase in cell viability in encapsulated cryogels for a range of thawing periods. We conclude that incorporation of COOH-PLL during cryogelation preserved cell functionality while retaining fundamental cryogel physical properties, thereby making it a promising platform for tissue-engineering scaffolds, particularly for vascular tissue engineering, or cell preservation within microgels.

Cell encapsulation and cryostorage in PVA-gelatin cryogels: incorporation of carboxylated Îµ-poly-L-lysine as cryoprotectant.

Il est souhaitable de produire cryopreservable charg&eacute;s de cellule ing&eacute;nierie tissulaire &eacute;chafaudages dont les propri&eacute;t&eacute;s finales peuvent &ecirc;tre ajust&eacute;es durant la d&eacute;cong&eacute;lation imm&eacute;diatement avant leur utilisation. Alcool polyvinylique (PVA)-solutions bas&eacute;s aux plates-formes dans laquelle cryoprotected des suspensions cellulaires peuvent &ecirc;tre transform&eacute;es en un &eacute;chafaudage pr&ecirc;t &agrave; l&#39;emploi, charg&eacute; de cellule par un processus de cryogelation. Dans cette &eacute;tude, tel un syst&egrave;me PVA, avec le DMSO comme le cryoprotecteur, a &eacute;t&eacute; d&eacute;velopp&eacute; avec succ&egrave;s. Cellules de muscle lisse vasculaire (CMLV)-encapsul&eacute;s criogels ont &eacute;t&eacute; &eacute;tudi&eacute;s dans des conditions de contrainte cyclique et en co-culture avec des cellules endoth&eacute;liales vasculaires pour imiter l&#39;environnement exp&eacute;rience in vivo, dans un cadre de tissu vasculaire-ing&eacute;nierie de ces cellules. Compte tenu de la cytotoxicit&eacute; que DMSO impose en ce qui concerne la proc&eacute;dure de production, carboxyl&eacute; poly-L-lysine (COOH-PLL) a &eacute;t&eacute; substitu&eacute;s en tant que non cytotoxique cryoprotecteur pour permettre plus, plus lent d&eacute;gel des p&eacute;riodes pour g&eacute;n&eacute;rer des criogels plus stable. CMLV encapsul&eacute; avec le DMSO en tant que cryoprotecteur a r&eacute;pondu &agrave; 10 % de souche cyclique avec alignement accru et la prolif&eacute;ration. Les cellules ont &eacute;t&eacute; conserv&eacute;s congel&eacute;s pendant 1 mois sans perte de viabilit&eacute; par rapport au d&eacute;givrage imm&eacute;diat. Criogels encapsul&eacute; SMC soutenu &eacute;galement avec succ&egrave;s co-culture de cellules endoth&eacute;liales fonctionnelle. Substitution de COOH-PLL &agrave; la place de DMSO a entra&icirc;n&eacute; une augmentation significative dans la viabilit&eacute; des cellules en criogels encapsul&eacute; pour une s&eacute;rie de p&eacute;riodes de d&eacute;gel. Nous concluons que l&#39;incorporation de COOH-PLL pendant cryogelation pr&eacute;serv&eacute; des fonctionnalit&eacute;s de cellules tout en conservant les propri&eacute;t&eacute;s physiques fondamentales cryogel, ce qui en fait une plate-forme prometteuse pour &eacute;chafaudages de l&#39;ing&eacute;nierie tissulaire, en particulier pour l&#39;ing&eacute;nierie des tissus vasculaires, ou la pr&eacute;servation de la cellule au sein de microgels.

Cell encapsulation et cryoconservation en PVA-g&eacute;latine criogels : incorporation de carboxyl&eacute;s &epsilon;-poly-L-lysine comme cryoprotectant.

&Egrave; auspicabile per produrre cryopreservable cella carico ponteggi ingegneria tessutale cui propriet&agrave; finale pu&ograve; essere regolata durante il processo di scongelamento immediatamente prima dell&#39;uso. Alcol polivinilico (PVA)-basato su soluzioni forniscono piattaforme in cui cryoprotected sospensioni cellulari possono essere trasformati in un ponteggio ready-to-use, cella di carico da un processo di cryogelation. In questo studio, tale sistema PVA, con DMSO come crioprotettore, &egrave; stato sviluppato con successo. Cellule muscolari lisce vascolari (vSMC)-Criogel incapsulati sono stati studiati in condizioni di sforzo ciclico e in co-culture con le cellule endoteliali vascolari per simulare l&#39;ambiente di queste cellule esperienza in vivo in un ambiente di ingegneria dei tessuti vascolari. In considerazione la citotossicit&agrave; che DMSO impone per quanto riguarda la procedura di produzione, carbossilata poly-L-lisina (COOH-PLL) fu sostituito come crioprotettore non citotossiche per consentire pi&ugrave;, pi&ugrave; lento scongelamento periodi per generare Criogel pi&ugrave; stabile. VSMC incapsulato con DMSO come crioprotettore risposto al 10% deformazione ciclica con maggiore allineamento e proliferazione. Le cellule sono state immagazzinate congelati per 1 mese senza perdita di redditivit&agrave; rispetto all&#39;immediato scongelamento. SMC-incapsulati Criogel supportato anche con successo co-culture funzionale delle cellule endoteliali. Sostituzione di COOH-PLL al posto di DMSO ha provocato un aumento significativo nella vitalit&agrave; cellulare in Criogel incapsulata per una vasta gamma di periodi di scongelamento. Concludiamo che incorporazione di COOH-PLL durante cryogelation conservata funzionalit&agrave; cellulare mantenendo propriet&agrave; fisiche fondamentali cryogel, rendendo cos&igrave; una piattaforma promettente per ponteggi ingegneria tissutale, particolarmente per l&#39;ingegneria dei tessuti vascolari, o conservazione di cellule all&#39;interno di microgels.

Nihal E. Vrana

Biomatériaux et Bioingénieriee

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Multi-Scale Modification of Metallic Implants With Pore Gradients, Polyelectrolytes and Their Indirect Monitoring In vivo