Collagen Coatings Research Articles

Collagen nanofibres are a biomimetic substrate for the serum-free osteogenic differentiation of human adipose stem cells

Electrospinning has recently gained widespread attention as a process capable of producing nanoscale fibres that mimic native extracellular matrix. In this study, we compared the osteogenic differentiation behaviour of human adipose stem cells (ASCs) on a 3D nanofibre matrix of type I rat tail collagen (RTC) and a 2D RTC collagen-coated substrate, using a novel serum-free osteogenic medium. The serum-free medium significantly enhanced the numbers of proliferating cells in culture, compared to ASCs in traditional basal medium containing 10% animal serum, highlighting a potential clinical role for in vitro stem cell expansion. Osteogenic differentiation behaviour was assessed at days 7, 14 and 21 using quantitative real-time RT-PCR analysis of the osteogenic genes collagen I (Coll I), alkaline phosphatase (ALP), osteopontin (OP), osteonectin (ON), osteocalcin (OC) and core-binding factor-alpha (cbfa1). All genes were upregulated (>one-fold) in ASCs cultured on nanofibre scaffolds over 2D collagen coatings by day 21. Synthesis of mineralized extracellular matrix on the scaffolds was assessed on day 21 with Alizarin red staining. These studies demonstrate that 3D nanoscale morphology plays a critical role in regulating cell fate processes and in vitro osteogenic differentiation of ASCs under serum-free conditions.

Establishment of a new human glioblastoma multiforme cell line (WJ1) and its partial characterization.

(1) A new human glioblastoma multiforme (GBM) cell line, WJ1, was established from the tissue derived from a 29-year-old patient diagnosed with a grade IV GBM. (2) The WJ1 cell line has been subcultured for more than 80 passages in standard culture media without feeder layer or collagen coatings. (3) GBM cells grow in vitro with distinct morphological appearance. Ultrastructural examination revealed large irregular nuclei and pseudo-inclusion bodies in nuclei. The cytoplasm contained numerous immature organelles and a few glia filaments. Growth kinetic studies demonstrated an approximate population doubling time of 60 h and a colony forming efficiency of 4.04%. The karyotype of the cells was hyperdiploid, with a large subpopulation of polyploid cells. Drug sensitivities of DDP, VP-16, tanshinone IIA of this cell line were assayed. They showed a dose- and time-dependent growth inhibition effect on the cells. (4) Orthotopic transplantation of GBM cells into athymic nude mice induced the formation of solid tumor masses about 6 weeks. The cells obtained from mouse tumor masses when cultivated in vitro had the same morphology and ultrastructure as those of the initial cultures. (5) This cell line may provide a useful model in vitro and in vivo in the cellular and molecular studies as well as in testing novel therapies for human glioblastoma multiforme.

Effect of Collagen Coating on Lipid Accumulation and Differentiation on 3T3-L1 Preadipocyte Treated with Conjugated Linoleic Acid

The purpose of this study is to make use of trans10,cis12 CLA (t-CLA) that has potential for proliferation and differentiation to form adipocyte on the collagen-coated surface. Results provided evidences of good adhesion, growth, viability, and differentiation of adipocyte on collagen-coated surface compared with non-coated surface. Also, the results showed that mouse 3T3-L1 preadipocyte can be successfully and reproducibly cultured on the collagen-coated surface, and the adipocyte precursor cells placed on the collagen-coated surface are able to undergo full maturation into adipocytes in the control cells. Moreover, glycerol-3-phosphate dehydrogenase (GPDH) activity in 3T3-L1 preadipocyte cultured on collagen-coated surface with t-CLA was higher than that on polystyrene (PS) surface due to higher cell adhesion and cell viability. These results suggest that collagen coating may provide a promising approach to develop a new adipocyte replacement strategy using CLA.

Protein Kinase C δ Activated Adhesion Regulates Vascular Smooth Muscle Cell Migration

Vascular smooth muscle cell (VSMC) migration, fundamental in the pathophysiology of atherogenesis and restenosis, is a coordinated process governed by the formation and disassembly of focal adhesions. Previous studies have demonstrated that VSMC migration is regulated via a signaling network involving protein kinase C delta (PKCdelta). In these studies, we test the hypothesis that PKCdelta regulates VSMC migration through modulation of cell adhesion. Using primary VSMCs isolated from PKCdelta wild type (+/+) and knock-out (-/-) mice, the effects of PKCdelta on VSMC migration and adhesion were assessed by chemotaxis and cell adhesion. In evaluating cell migration, we found a decrease in platelet-derived growth factor-BB (PDGF-BB; 5 ng/mL x 6 h) stimulated migration of PKCdelta-/-VSMCs as compared to PKCdelta+/+VSMCs, by 59.4 +/- 5.9% (P < 0.01). A similar reduction in migration of PKCdelta-/-VSMCs (66.5 +/- 5.7%, P < 0.01) was also observed on collagen-coated (COL) membranes. Next, we examined cell attachment, a critical step of migration. PKCdelta-/-VSMCs exhibited significantly reduced adherence by 50.3 +/- 1.8% (P < 0.01). A similar defect of PKCdelta-/-VSMCs was also observed on the COL surface, 30.7 +/- 2.3% (P < 0.01). Interestingly, PDGF-BB did not stimulate attachment of VSMCs of either genotype. Consistent with these results, Rottlerin (2 microM), a selective inhibitor of PKCdelta, blocked migration and attachment of VSMCs by 56.8 +/- 3.4% (P < 0.01) and 37.7 +/- 1.9% (P < 0.01), respectively. Taken together, our data indicate that PKCdelta activation is necessary for VSMC adhesion, which could, at least in part, contribute to the regulatory function of this kinase in cell migration thus pathogenesis of vascular lesions.

Electrochemically-assisted deposition of biomimetic hydroxyapatite–collagen coatings on titanium plate

A biomimetic bone-like composite, made of self-assembled collagen fibrils and carbonate hydroxyapatite nanocrystals, has been performed by an electrochemically-assisted deposition on titanium plate. The electrolytic processes have been carried out using a single type I collagen molecules suspension in a diluted Ca(NO3)2 and NH4H2PO4 solution at room temperature and applying a constant current for different periods of time. Using the same electrochemical conditions, carbonate hydroxyapatite nanocrystals or reconstituted collagen fibrils coatings were obtained. The reconstituted collagen fibrils, hydroxyapatite nanocrystals and collagen fibrils/apatite nanocrystals coatings have been characterized chemically, structurally and morphologically, as well as for their ability to bind fibronectin (FN). Fourier Transform Infrared microscopy has been used to map the topographic distribution of the coating components at different times of electrochemical deposition, allowing to single out the individual deposition steps. Moreover, roughness of Ti plate has been found to affect appreciably the nucleation region of the inorganic nanocrystals. Laser scanning confocal microscopy has been used to characterize the FN adsorption pattern on a synthetic biomimetic apatitic phase, which exhibits a higher affinity when it is inter-grown with the collagen fibrils. The results offer auspicious applications in the preparation of medical devices such as biomimetic bone-like composite-coated metallic implants.

Collagen Coating on Hydroxyapatite Surfaces Modified with Organosilane by Chemical Vapor Deposition Method

Type I collagen was coated onto the modified surfaces of hydroxyapatite (HAp) sintered body. The interfacial interaction between collagen and HAp in a nano-region was controlled by depositing the organosilane of n-octadecyltrimethoxysilane (ODS: -CH3) or aminopropyltriethoxysilane (APTS: -NH2) with a chemical vapor deposition method. The surfaces were elaborated by X-ray photoelectron spectroscopy, zeta-potential, and contact angle measurements; the Si and/or N peaks were detected, and the contact angles and surface energies were apparently different on the modified surfaces. The morphologies of collagen adsorbed on the surfaces of HAp and HAp deposited with APTS were similar, however that of the surface with ODS was apparently different, due to the hydrophobic interaction between the organic head group of -CH3 and residual groups of collagen.

Influence of extracellular matrix coatings on implant stability and osseointegration: An animal study

Aim of the present study was to test the hypothesis that the application of components of the extracellular matrix such as glycosaminoglycans used as implant surface coatings in combination with collagen, with and without growth factor, can lead to enhanced ossification and thus improve implant stability compared with collagen coatings alone. Twenty miniature pigs received 120 experimental titanium implants in the mandible. Three types of surface coatings were created: (1) collagen type I (coll), (2) collagen type I/chondroitin sulphate (coll/CS), (3) collagen type I/chondroitin sulphate/BMP-4 (coll/CS/BMP). Periimplant bone formation was assessed within a defined recess along the length axis of the implant. Bone-implant contact (BIC) and bone volume density (BVD) were determined, using both histomorphometry and synchrotron radiation micro computed tomography (SRmicroCT). To measure implant stability, resonance frequency analysis was applied after implantation and 1, 3, 7, and 22 weeks after placement. BIC was highest for coll/CS coated implants, followed by coll, p = 0.082. Histomorphometric BVD did not significantly change for any coating. SRmicroCT analysis showed an increased BVD for collagen coated implants, compared with the other two surface coatings. Implant stability showed a decrease for all coatings up to the third week. At 22 weeks, all coatings showed an increase in stability without reaching their initial level. Highest stability was reached for coll coated implants, p = 0.051. It was concluded that collagen and coll/CS implant coatings have advantageous characteristics for peri-implant bone formation, compared with the further integration of BMP-4.

The surface energy of various biomaterials coated with adhesion molecules used in cell culture

This study calculates the surface energy of polystyrene tissue culture plastic, silicon, silicon dioxide and indium tin oxide, all of which have applications in tissue culture. The adhesion molecules: collagen, fibronectin, poly- l-ornithine and poly- d-lysine, were coated onto these various surfaces, and the surface energy of the coated substrates calculated. Coating with fibronectin was found to produce a monopolar acidic surface while poly- d-lysine, poly- l-ornithine and collagen coatings were found to produce monopolar basic surfaces. The calculated surface energy components of the coated materials were then used to give a quantitative determination of the magnitude of their hydrophobicity. It was concluded that collagen, polylysine and polyornithine could provide a hydrophobic or hydrophilic surface depending on the underlying substrates they were coated on. The measurement obtained for fibronectin, unlike the other adhesion molecules, was independent of the underlying surface and remained hydrophobic on all substrates tested. Wetting experiments were carried out on the coated substrates, using the tissue culture medium Dulbeccos modified eagles medium, both containing and not containing serum proteins, and saline solution. These liquids that are commonly used in tissue culture, were then used to provide information how these liquids behave on various substrates coated with the adhesion molecules. Results show that fibronectin coated surfaces represent the most phobic surface for all three liquids. The findings of this study can be used in cell manipulation studies and provide a valuable data set for the biomedical and research industries.

Hepatocytes primary culture from the Neotropical fish, trahira Hoplias malabaricus (Bloch)

Hepatocytes were isolated and cultured from Hoplias malabaricus using a non‐enzymatic protocol. From 6·9 to 9·4 × 107 hepatocytes g−1 of liver were isolated and cell viability was 65–85%. Fish hepatocytes attached well to untreated polystyrene flasks (Corning) as well as on treated surfaces with extracellular matrix proteins, i.e. fibronectin, matrigel or type I collagen coatings. Cells rapidly started migrating and reorganizing in cord‐like groups after seeding, with spaces similar to bile canaliculi in vivo. Prominent nucleolus and euchromatin‐rich rounded nucleus, abundant mitochondria, well‐developed rough endoplasmic reticulum, polysomes and Golgi apparatus were seen under ultrastructural analysis. Cells remained functional and metabolically active after 6 days in culture. The protocol established in the current work provides the basis for further studies of native fishes for accurate in vitro toxicological studies.

Mechanical properties of the bioabsorbable polyglycolic acid-collagen nerve guide tube

Bioabsorbable nerve tubes made from polyglycolic acid (PGA) coated with collagen are now used widely for patients who have suffered nerve injury. The main function of nerve tubes is to maintain a space for nerve regeneration in the body against rapid invasion by the surrounding tissue until the new nerve tissue has recovered. However, no precise mechanical testing has ever been carried out on bioabsorbable nerve tubes. The aim of this study was therefore to evaluate the mechanical properties of PGA– collagen tubes and to analyze the degree to which they are able to maintain the patency of the conduit for the recovering nerve. Nerve tubes with diameters of 3 and 4 mm were used in this experiment. The tubes were made from cylindrically woven PGA fibers that had been given 5, 10, or 27 coats of collagen, which was finally crosslinked dehydrothermally at 140°C for 24 h. Both in vitro and in vivo tests were carried out. For in vitro testing, the nerve tube samples were immersed in saline at 37°C for up to 8 weeks. For in vivo testing, samples were implanted subcutaneously into rabbits and observed for up to 16 weeks after implantation. Resistance during compression stress was measured for each sample with the aid of a tensile tester. The collagen coating enhanced the mechanical properties of the tubes, particularly in the first 2 weeks following immersion. The tubes coated with collagen 27 times (27T tubes) were 180% stronger than either the 5T or the 10T tubes. The time taken for the initial mechanical parameters, such as tube rigidity, to be reduced by half was 14 days or more. The reduction in the mechanical strength of the tubes in vivo occurred more rapidly than in vitro. POLYM. ENG. SCI., 46: 1461–1467, 2006. © 2006 Society of Plastics Engineers

Preparation of bioelectret collagen and its influence on cell culture in vitro

Collagen extracted from pigskin was corona-charged negatively by a specifically designed device. Different charging voltages, temperatures and times were applied to prepare collagen bioelectret. The decline of the surface potential of the bioelectret under different treatment was then determined. The data showed that the surface potential was markedly varied with the charging conditions. The optimal values of three parameters for charging collagen coatings were defined as follows: voltage, 8 KV; temperature, 40 degrees Celsius; time, 25 min. Treatment of the bioelectret with distillated water, or saline solution (0.9%) or culture medium induced a sharp decrease of the surface potential. In addition, we investigated the effects of the charged collagen on cell growth and intracellular calcium level of three types of cultured mammalian cell lines, including Chinese hamster ovary CHO cells, human cervix uteri tumor HeLa cells and human promyelocytic HL-60 cells. Cell growth and the intracellular calcium level were determined by MTT reagent-based assay and a fluorescent probe Fura-2, respectively. The results showed that negatively charged collagen stimulated the growth of CHO or HL-60 cell line but inhibited the growth of HeLa cell line. Furthermore, after attaching to the charged collagen, the intracellular calcium level of CHO cells increased, while that of HeLa cells decreased. Thus we proposed for the first time that collagen bioelectret could differentially modulate the growth of different cells, by an unknown mechanism that probably involves a role of intracellular calcium.

Preliminary β-tricalcium phosphate coating prepared by discharging in a modified body fluid enhances collagen immobilization onto titanium

Because of its excellent scaffold properties toward bone cells, collagen has been recognized as a promising extracellular matrix protein for surface modification of titanium implants. Hydroxyapatite (HA) coatings have been investigated as a preliminary coating for collagen immobilization on titanium implants. However, the composition of HA-collagen is recognized as being difficult, and while many studies have suggested that biodegradable beta-tricalcium phosphate (beta-TCP) has better osteoconductivity than HA, the efficiency of preliminary beta-TCP coating for collagen immobilization on titanium surfaces has yet to be evaluated. This investigation aimed to evaluate the applicability of HA and beta-TCP coatings, prepared by discharging in modified body fluids, as preliminary collagen coatings. To increase collagen induction on preliminary HA and beta-TCP coatings, we used a new cathodic polarization method. X-ray photoelectron spectroscopy revealed that the bonding strength between the collagen NH(+) amino groups of collagen and phosphate (PO(4) (3-)) was greater on the beta-TCP coating than the HA coating. The preliminary beta-TCP coating was tightly crosslinked with RCOO(-) carboxyl groups of the collagen molecules and showed high cellular responses, even in the early stage of cell cultivation. Thus, this coating was found to be more effective than HA as a preliminary coating for collagen immobilization on titanium implants.

RGDS and DGEA-induced [Ca 2+] i signalling in human dermal fibroblasts

A pulse of short peptides, RGDS and DGEA in the millimolar range, immediately elicits in normal human fibroblasts a transient increase of intracellular Ca 2+ ([Ca 2+] i). In the present study, we show that this [Ca 2+] i occurs in an increasing number of cells as a function of peptides concentration. It is specific of each peptide and inhibited at saturating concentration of the peptide in the culture medium. The [Ca 2+] i transient depends on signalling pathways slightly different for DGEA and RGDS involving tyrosine kinase(s) and phosphatase(s), phospholipase C, production of inositol-trisphosphate and release of Ca 2+ from the cellular stores. GFOGER, the classical collagen binding peptide of α1- α2- and α11-β1 integrins, in triple helical or denatured form, does not produce any Ca 2+ signal. The [Ca 2+] i signalling induced by RGDS and DGEA is inhibited by antibodies against β1 integrin subunit while that mediated by RGDS is also inhibited by antibodies against the α3 integrin. Delay in the acquisition of responsiveness is observed during cell adhesion and spreading on a coat of fibronectin for RGDS or collagen for DGEA or on a coat of the specific integrin-inhibiting antibodies but not by seeding cells on GFOGER or laminin-5. This delay is suppressed specifically by collagenase acting on the collagen coat or trypsin on the fibronectin coat. Our results suggest that free integrins and associated focal complexes generate a Ca 2+ signal upon recognition of DGEA and RGDS by different cellular pathways.

Characterization of the Surface Biocompatibility of the Electrospun PCL-Collagen Nanofibers Using Fibroblasts

The effect of nanofiber surface coatings on the cell's proliferation behavior was studied. Individually collagen-coated poly(epsilon-caprolactone) (PCL) nanofibers (i.e., Collagen-r-PCL in the form of a core-shell structure) were prepared by a coaxial electrospinning technique. A roughly collagen-coated PCL nanofibrous matrix was also prepared by soaking the PCL matrix in a 10 mg/mL collagen solution overnight. These two types of coated nanofibers were then used to investigate differences in biological responses in terms of proliferation and cell morphology of human dermal fibroblasts (HDF). It was found that coatings of collagen on PCL nanofibrous matrix definitely favored cells proliferation, and the efficiency is coating means dependent. As compared to PCL, the HDF density on the Collagen-r-PCL nanofiber membrane almost increased linearly by 19.5% (2 days), 22.9% (4 days), and 31.8% (6 days). In contrast, the roughly collagen-coated PCL increased only by 5.5% (2 days), 11.0% (4 days), and 21.0% (6 days). SEM observation indicated that the Collagen-r-PCL nanofibers encouraged cell migration inside the scaffolds. These findings suggest that the Collagen-r-PCL nanofibers can be used as novel functional biomimetic nanofibers toward achieving excellent integration between cells and scaffolds for tissue engineering applications.

Effects of fibril- or fixed-collagen on matrix metalloproteinase-1 and tissue inhibitor of matrix metalloproteinase-1 production in the human hepatocyte cell line HLE

Matrix metalloproteinase-1 (MMP-1) and tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) are central to the spontaneous resolution of liver fibrosis. The mechanisms involved have been investigated in hepatic stellate cells (HSC), but not in hepatocytes. We investigated the effects of fibril- and fixed-collagen on MMP-1 and TIMP-1 production in hepatocytes, using the HLE cell line. Fibril type I and IV collagen were prepared by HCl digestion of type I and IV collagen, respectively. For fixed-collagen, culture dishes were coated with fibril type I or IV collagen and fixed by ultraviolet. Type I collagenase activity was measured using fluorescein isothiocyanate-labeled type I collagen. MMP-1 and TIMP-1 in HLE cells were measured by a one-step sandwich enzyme immunoassay. Both fibril type I and IV collagen significantly increased type I collagenase activity about two-fold compared with no fibril collagen. The effects of the fibril collagen were not affected by the coating condition. There was no significant difference in the effects on collagenase activity between cells cultured in medium containing fibril type I collagen and those cultured in the presence of type IV collagen. Both types of fibril collagen significantly increased MMP-1 production, and showed more than 10-fold higher levels of MMP-1 than the control. The enhanced MMP-1 production by fibril collagens was unaffected by the coating condition. By contrast, TIMP-1 production was not changed by the addition of fibril type I or IV collagen, and neither was it affected by the coating conditions. Coating with type I collagen significantly suppressed MMP-1 production by almost one-tenth compared with no coating. By contrast, TIMP-1 production was not affected by either the absence of a collagen coat or by increasing the concentration of the coating collagen. These results indicated that, in HLE cells, fibril- and fixed-collagen have opposite effects on MMP-1 production without affecting TIMP production. Fibril collagen induced collagenase activity by up-regulation of MMP-1 production without affecting TIMP-1 production. By contrast, fixed collagen reduced MMP-1 production. Our results suggest that hepatocytes might also play an important role in the regulation of the hepatic fibrosis alongside HSC.

Osteoconductive modifications of Ti-implants in a goat defect model: characterization of bone growth with SR μCT and histology

In this work the osteoconductive potential of coatings for titanium implants using different extracellular matrix components was evaluated. Cylindrical implants with two defined cavities A and B were coated with collagen type I, type III, or RGD peptide, and placed in the femur of goats together with an uncoated reference state. Bone contact and volume were determined after 5 and 12 weeks implantation, using both histomorphometry and synchrotron radiation micro computed tomography (SR μCT) as the methods complement each other: SR μCT allows for a high precision of bone detection due to the large number of analysed slices per sample, while histology offers a better lateral resolution and the possibility of additionally determining bone contact. Both methods revealed similar tendencies in bone formation for the differently bio-functionalized implants, with the SR μCT data resulting in significant differences. After 5 and 12 weeks, all three coatings showed a significant increase in bone volume over the uncoated reference, with the highest results for the collagen coatings. The coating consisting of just the RGD-sequence to improve cell adhesion showed only a slight improvement compared with the reference material. For uncoated titanium, RGD, and especially collagen type I, the response in cavity A, situated in denser bone, was stronger than in cavity B. Collagen type III, on the other hand, appeared to be the more effective coating in areas of lesser bone density as represented by cavity B. These results indicate that matrix molecules (or combinations thereof) are capable of generating the appropriate signals for the specific microenvironment around implants and can thus accelerate the bone formation process and increase the stability of implants.

Microarray Assessment of Fibronectin, Collagen and Integrin Expression and the Role of Fibronectin–Collagen Coating in the Growth of Normal, SV40 T-antigen-immortalised and Malignant Human Oral Keratinocytes

Extracellular matrix proteins affect the growth and survival of epithelial tissues. Accordingly, surface coating with fibronectin and collagen is a common practice for promoting keratinocyte culture. In this study, the expression of fibronectin and collagen-related factors, including integrins, by normal (NOK), SV40 T-antigen-immortalised (SVpgC2a) and malignant (SqCC/Y1) human oral keratinocytes, under standardised, serum-free conditions, was investigated by using microarray analysis. Cell growth was also studied in the presence and absence of a matrix consisting of human fibronectin and bovine collagen type I (FN-COL). Fibronectin transcripts were abundant in all cells, whereas 16 of 29 collagen chains and 14 of 24 integrin subunits were variably detected. With regard to both the expression level and the number of transcripts, higher collagen and lower integrin expression was observed in SVpgC2a cells than in NOKs and SqCC/Y1 cells. The cell types differed with regard to colony-forming efficiency and the rate and kinetics of growth at high cell density. For all cell types, FN-COL coating consistently stimulated cell migration, without influencing growth in mass culture or clonal density. The results demonstrate the transcription of genes associated with the formation and function of fibronectin and collagen in oral epithelium, and variably altered expression patterns in transformed states, and show that keratinocyte lines can be successfully transferred without the stimulus from extracellular FN-COL.

Modification of Ti6AL4V surfaces using collagen I, III, and fibronectin. II. Influence on osteoblast responses.

Responses of osteoblastic cells are influenced by morphology and composition of the extracellular matrix, and this fact has been used to improve the biological acceptance of implants by modifying the surfaces with components of the extracellular matrix (ECM). In this study, the effect of the collagen types I and III on adhesion, proliferation, and differentiation was studied, using primary osteoblastic cells from rat calvariae. Differences in alkaline phosphatase activity (ALP) and collagen synthesis were observed between differently composed collagen coatings. An increase in collagen type III resulted in an increase in collagen synthesis and a concomitant decrease in ALP activity and Ca deposition. Initial adhesion mechanism of the cells depended on the substrate (titanium, collagen, fibronectin).

Collagen Coating Promotes Biocompatibility of Semiconductor Nanoparticles in Stratified LBL Films

Nanostructured thin films fabricated from semiconductor nanoparticles (NPs) are of great interest for biomedical applications, but NP materials based on heavy metals can be cytotoxic. In this work, the preparation of semiconductor NPs followed the protocol of layer-by-layer (LBL) assembly, which alleviates this problem. Collagen/poly(acrylic acid) bilayers were added to CdTe/polycation LBL films to produce porous collagen bilayers. Such stratified multilayer systems showed successful cell attachment and survival while native NP films were strongly cytotoxic.

Rat costochondral cell characteristics on poly ( l-lactide-co- ε-caprolactone) scaffolds

This study was designed to examine the adhesion, proliferation, and morphology of chondrocytes on new scaffolds; and to examine these cells histologically for the ability of the chondrocytes to maintain chondrogenic properties after subcutaneous implantation into nude mice. Both 75:25 poly ( l-lactide-co- ε-caprolactone) (75PLC) and 50:50 poly ( l-lactide-co- ε-capro-lactone) scaffold (50PLC) were tested as a scaffold for rat costochondral resting zone chondrocytes in comparison with a type I collagen sponge scaffold (collagen scaffold). Both of the poly ( l-lactide-co- ε-caprolactone) scaffolds (75PLC and 50PLC) were coated with type I collagen solution and the effects of the collagen coat (hybrid-PLC) were also examined. The hybrid-75PLC bound the same number of cells as the collagen scaffold, whereas the 75PLC and the 50PLC bound 60% and 50% fewer cells than the collagen scaffold, respectively. The cell growth on the scaffolds progressed with culture time in all scaffolds. Cell morphology was assessed by scanning electron microscopy for differences in the structure of cellular interaction. Chondrocytes on every scaffold maintained a spherical shape. The hybrid-PLCs were superior to the PLCs with respect to the number of cells attached. The PLCs had an advantageous degradation characteristic in that they retained their original shape better than the collagen scaffold. Additionally, in the PLCs seeded, the cells retained their integrity 4 weeks after implantation, although the volume of collagen scaffold decreased by 50%.