Collagen Hyaluronic Acid Research Articles

Effects of Middle Ear Packing with Collagen Polyvinylpyrrolidone and Hyaluronic Acid in Guinea Pigs

ABSTRACTObjective: The aim of this study was to evaluate otoscopic and microscopic changes produced on the healthy mucosa of the middle ear (ME) and tympanic membrane (TM) of guinea pigs after packing with a collagen polyvinylpyrrolidone (CPVP) sponge soaked in hyaluronic acid (HA). Material and methods: In 24 guinea pigs, myringotomy on the right side was created and the ME was packed as follows: Group I (n = 6): Absorbable gelatin sponge (AGS) soaked in saline solution; Group II (n = 6): AGS sponge soaked in HA, Group III (n = 6): CPVP sponge soaked in saline solution, Group IV (n = 6): CPVP sponge soaked in HA. Four weeks after miringotomy, the ME and TM integrity and residual packing material were evaluated otoscopically. Histologically, we evaluated inflammatory changes on the ME mucosa. Results: All animals in Groups I and II showed residual packing material (p < .001 ANOVA, TUKEY). Histologically, more inflammation was observed in Groups I, II, and III than in Group IV (p < .001 ANOVA, TUKEY). Group IV showed greater fibroblastic reaction (p < .02, ANOVA, TUKEY) versus other groups. Conclusion: The CPVP sponge soaked in HA used as ME packing material is biocompatible and nontoxic, because it produces minimal inflammatory changes on the healthy mucosa of the ME and TM of guinea pigs. However, more research with injured mucosa is needed to validate its usefulness in otosurgery.

Fabrication of Quantum Dot-Conjugated Collagen/Hyaluronic Acid Porous Scaffold

A quantum dot (QD)-conjugated collagen-hyaluronic acid (HA) porous scaffold was combined with our previously reported animal model of mice inferior epigastric flaps and QD infusion to study scaffold angiogenesis. A CdSe/ZnS QD-labeled collagen/HA scaffold was fabricated and examined with a confocal microscope. The degradation rate of the scaffold was inversely related to 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide concentration used in cross-linking. There was no cytotoxicity of the QDs as determined by MTT colorimetric assay. Results of the animal implantation study revealed no difference in acute tissue inflammation between scaffolds with or without QD labeling. To study scaffold angiogenesis, we infused the implanted QD-conjugated collagen/HA scaffold with QD of different fluorescence, which can be simultaneously identified by confocal microscope. By these evaluations, we conclude that QD-conjugated collagen/HA porous scaffold is not different from that without conjugation and can be used in our animal model of scaffold angiogenesis without compromising results.

In situ forming collagen–hyaluronic acid membrane structures: Mechanism of self-assembly and applications in regenerative medicine

Bioactive, in situ forming materials have the potential to complement minimally invasive surgical procedures and enhance tissue healing. For such biomaterials to be adopted in the clinic, they must be cost-effective, easily handled by the surgeon and have a history of biocompatibility. To this end, we report a novel and facile self-assembling strategy to create membranes and encapsulating structures using collagen and hyaluronic acid (HA). Unlike membranes built by layer-by-layer deposition of oppositely charged biomolecules, the collagen–HA membranes described here form a diffusion barrier upon electrostatic interaction of the oppositely charged biomolecules, which is further driven by osmotic pressure imbalances. The resulting membranes have a nanofibrous architecture, a thicknesses of 130μm and a tensile modulus (0.59±0.06MPa) that can increase 7-fold using carbodiimide chemistry (4.42±1.46MPa). Collagen–HA membranes support mesenchymal stem cell proliferation and have a slow and steady protein release profile (7% at day 28), offering opportunities for targeted tissue regeneration. We demonstrate the capacity to encapsulate cells by injecting HA into the collagen solution, and enhance allograft and implant biocompatibility through a coating technique. This study describes a novel mechanism of collagen–HA membrane formation and provides the groundwork to apply these membranes in a variety of tissue engineering applications.

Hyaluronic acid–collagen network interactions during the dynamic compression and recovery of cartilage

A compression cell designed to fit inside an NMR spectrometer was used to investigate (i) the in situ dynamic strain response and structural changes of the internal pore network, and (ii) the diffusion and flow of interstitial water, in full thickness cartilage samples as they were mechanically deformed under a constant compressive load (pressure) and then allowed to recover (swell again) when the load was removed. Selective enzymatic digestion of the collagen fibril network and the glycopolysaccharide hyaluronic acid (HA) was performed to mimic some of the structural and compositional changes associated with osteoarthritis. Digestion of collagen gave rise to mechanical ‘dynamic softening’ and—perhaps more importantly—nearly complete loss in the ability to recover through swelling, both effects due to the disruption of the hierarchical structure and fibril interconnectivity in the collagen network which adversely affects its ability to deform reversibly and to properly regulate the pressurization and resulting rate and direction of interstitial fluid flow. In contrast, digestion of HA inside the collagen pore network caused the cartilage to ‘dynamically stiffen’ which is attributed to the decrease in the osmotic (entropic) pressure of the digested HA molecules confined in the cartilage pores that causes the network to contract and thereby become less permeable to flow. These digestion-induced changes in cartilage's properties reveal a complex relationship between the molecular weight and concentration of the HA in the interstitial fluid, and the structure and properties of the collagen fibril pore network, and provide new insights into how changes in either could influence the onset and progression of osteoarthritis.

Addition of hyaluronic acid improves cellular infiltration and promotes early-stage chondrogenesis in a collagen-based scaffold for cartilage tissue engineering

The response of mesenchymal stem cells (MSCs) to a matrix largely depends on the composition as well as the extrinsic mechanical and morphological properties of the substrate to which they adhere to. Collagen–glycosaminoglycan (CG) scaffolds have been extensively used in a range of tissue engineering applications with great success. This is due in part to the presence of the glycosaminoglycans (GAGs) in complementing the biofunctionality of collagen. In this context, the overall goal of this study was to investigate the effect of two GAG types: chondroitin sulphate (CS) and hyaluronic acid (HyA) on the mechanical and morphological characteristics of collagen-based scaffolds and subsequently on the differentiation of rat MSCs in vitro. Morphological characterisation revealed that the incorporation of HyA resulted in a significant reduction in scaffold mean pore size (93.9μm) relative to collagen–CS (CCS) scaffolds (136.2μm). In addition, the collagen–HyA (CHyA) scaffolds exhibited greater levels of MSC infiltration in comparison to the CCS scaffolds. Moreover, these CHyA scaffolds showed significant acceleration of early stage gene expression of SOX-9 (approximately 60-fold higher, p<0.01) and collagen type II (approximately 35-fold higher, p<0.01) as well as cartilage matrix production (7-fold higher sGAG content) in comparison to CCS scaffolds by day 14. Combining their ability to stimulate MSC migration and chondrogenesis in vitro, these CHyA scaffolds show great potential as appropriate matrices for promoting cartilage tissue repair.

Effect of PEGylation on the Diffusion and Stability of Chitosan–DNA Polyplexes in Collagen Gels

Diffusion through the extracellular matrix (ECM) is a critical step for the delivery of nanoparticles and genes. Gene delivery requires a carrier that protects the nucleic acid from degradation and facilitates transport. Chitosan is a promising carrier. To increase the circulation time, PEGylation of the carrier is performed. However, the effect of PEGylation on the transport and stability of gene delivery systems in the ECM has only been studied in solutions containing ECM components. We used polymerized collagen and collagen-hyaluronic acid (HA) gels to study the effects of PEGylation on the diffusion and stability of chitosan-DNA polyplexes. We found that PEGylation of the polyplexes was required for diffusion to occur, and PEGylation increased the dissociation between DNA and chitosan to some extent. The presence of HA had a contradictory role: it decreased the penetration depth of PEGylated polyplexes into the gels and increased the diffusion of the polyplexes being mixed into the gels.

The responses of preosteoblasts to collagen/hyaluronic acid polyelectrolyte multilayer coating on titanium

AbstractThe purpose of this study was to investigate the effect of Collagen/hyaluronic acid (Col/HA) polyelectrolyte multilayer (PEM) coating on the behaviors and function of pre‐osteoblastic cells. Col/HA PEM coating was fabricated on acid etched Ti disc via layer‐by‐layer technique. The formation and properties of Col/HA PEM coating were investigated using scanning electron microscope (SEM), contact angle and quartz crystal microbalance (QCM). Moreover, mouse preosteoblasts were used to evaluate the effect of Col/HA PEM coating on cell behaviors and function. The results of in vitro evaluations showed that the Col/HA PEM coating could accelerate the proliferation and differentiation of preosteoblasts cells. Copyright © 2011 John Wiley &amp; Sons, Ltd.

Adipose-Derived Mesenchymal Stem Cells in Collagen—Hyaluronic Acid Gel Composite Scaffolds for Vocal Fold Regeneration

We sought to characterize the changes in the extracellular matrix (ECM) of the lamina propria following the implantation of autologous adipose-derived mesenchymal stem cells (ADSCs) in composite scaffolds in a rabbit vocal fold wound model. The ADSCs were co-cultured with collagen or hyaluronic acid gel. Each vocal fold was injured by localized resection and injected with ADSC complexes, ADSCs, or scaffolds or left untreated. From 15 days to 12 months, the vocal fold shape and the characteristics of the ECM components were analyzed. With implantation of the ADSC complexes, the collagen content was significantly increased and had a disorderly distribution at 3 months. Subsequently, it began to decrease and reached close to normal by 12 months. The hyaluronic acid content was increased at 40 days, but it was reduced to normal levels and was limited to the superficial and middle layers of the lamina propria over the following 12 months. Fibronectin continued to be scattered in the lamina propria, at peak levels at 40 days, and then decreased over the following 12 months to reach near-normal levels. At 12 months, the vocal folds had a normal surface. ADSC complexes can play a facilitatory role in vocal fold regeneration, regulating the generation and orderly distribution of ECM.

Effects of intense pulsed light irradiation on the content of collagen fibers, elastic fibers and hyaluronic acid in Kunming mouse skin.

Objective To investigate the effects of intense pulsed light (IPL) irradiation on the content of collagen fibers, elastic fibers and hyaluronic acid in Kunming mouse skin. Methods The dorsal skin of mice was divided into two areas: the right area was irradiated with IPL, and the left remaining unirradiated served as the control. Skin specimens were taken from the back of mice on day 1, 3, week 1, 2, 4 and 8 after the irradiation and subjected to staining with HE, sirius red and Gomori aldehyde-fuchsin for examinations of histological changes, type Ⅰ and Ⅲ collagen fibers and elastic fibers. The hydroxyproline and hyaluronic acid content in skin tissues of mice was determined with ultraviolet spectrophotometry and radioimmunoassay respectively. Results After irradiation, a significant increase was observed in dermal thickness on week 2 (t =4.623, P＜ 0.05), 4, and 8 (t = 3.904, P＜ 0.05), in type Ⅲ collagen fiber (t = 5.129, P＜ 0.05) on week 1,in type Ⅰ and Ⅲ collagen fibers on week 2, 4 and 8 (both P＜ 0.05), in elastic fibers from week 2 to 8 (P ＜0.05), and in hydroxyproline content from week 1 to 8 (all P ＜ 0.05) in the skin of mice compared with unirradiated mice. In detail, dermal thickness increased by 18.71% on week 4, and type Ⅲ collagen fiber by 40.54% in irradiated mice compared with unirradiated mice. Further more, the hyaluronic acid content was elevated from day 1 to 3, but gradually declined from week 1 to 8, and remained statistically higher from day 1 to week 8 (P ＜ 0.05) in irradiated mice compared to unirradiated mice. Conclusion IPL irradiation could induce an increase in the content of collagen fiber, elastic fiber and hyaluronic acid in the dorsal skin of mice. Key words: Intense pulsed light; Collagen; Elastic tissue; Hyaluronic acid; Mice

Wound healing effect of collagen-hyaluronic acid implanted in partially injured anterior cruciate ligament of dog

The purpose of this study was to evaluate the cell compatibility of collagen-hyaluronan (HA) substrate in vitro by assessing ACL cell cultures. Additionally, the use of collagen-HA substrate as a dressing material for partial ACL defects as well as its effect on collagen synthesis and angiogenesis were evaluated in vivo. The initial attachment and proliferation of dog ACL cells on silk matrix covered with collagen-HA substrate (SMCH) was greater than that observed on silk matrix alone. Silk matrix and SMCHs were implanted as dressing materials into partial ACL defects located at the knees of dogs, and they were harvested six weeks after implantation. A histological evaluation of the collagen-HA substrates revealed the presence of monocytes and the absence of giant cells in all cases. MT staining of the SMCH-grafted group showed a higher level of granulation tissue formation consisting of fibroblasts and collagen fibers compared to the silk matrix-grafted group. In addition, CD31 staining revealed that the SMCH-grafted area showed more blood vessel formation than the silk matrix-grafted area. These results suggest that the collagen-HA substrate was cell-compatible in vitro and enhanced collagen synthesis and new blood vessel formation in vivo.

Collagen–hyaluronic acid scaffolds for adipose tissue engineering

Three-dimensional (3-D) in vitro models of the mammary gland require a scaffold matrix that supports the development of adipose stroma within a robust freely permeable matrix. 3-D porous collagen-hyaluronic acid (HA: 7.5% and 15%) scaffolds were produced by controlled freeze-drying technique and crosslinking with 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride. All scaffolds displayed uniform, interconnected pore structure (total porosity approximately 85%). Physical and chemical analysis showed no signs of collagen denaturation during the formation process. The values of thermal characteristics indicated that crosslinking occurred and that its efficiency was enhanced by the presence of HA. Although the crosslinking reduced the swelling of the strut material in water, the collagen-HA matrix as a whole tended to swell more and show higher dissolution resistance than pure collagen samples. The compressive modulus and elastic collapse stress were higher for collagen-HA composites. All the scaffolds were shown to support the proliferation and differentiation 3T3-L1 preadipocytes while collagen-HA samples maintained a significantly increased proportion of cycling cells (Ki-67+). Furthermore, collagen-HA composites displayed significantly raised Adipsin gene expression with adipogenic culture supplementation for 8 days vs. control conditions. These results indicate that collagen-HA scaffolds may offer robust, freely permeable 3-D matrices that enhance mammary stromal tissue development in vitro.

A nano-fibrous assembly of collagen–hyaluronic acid for controlling cell-adhesive properties

We report an artificially fabricated extracellular matrix (ECM)-like nanostructure, which utilizes self-assembly of collagen and hyaluronic acid in a quasi two-dimensional space of tens-of-nm thickness, displaying different cellular adhesive characteristics depending on the structural properties between the fibril and non-fibril elements. This nano-fibrous assembly will facilitate a mechano-biological approach for the development of tissue-engineering scaffolds.

Effect of adipic dihydrazide modification on the performance of collagen/hyaluronic acid scaffold

Collagen and hydrazide-functionalized hyaluronic acid derivatives were hybridized by gelating and genipin crosslinking to form composite hydrogel. The study contributed to the understanding of the effects of adipic dihydrazide modification on the physicochemical and biological properties of the collagen/hyaluronic acid scaffold. The investigation included morphology observation, mechanical measurement, swelling evaluation, and collagenase degradation. The results revealed that the stability of composites was increased through adipic dihydrazide modification and genipin crosslinking. The improved biocompatibility and retention of hyaluronic acid made the composite material more favorable to chondrocytes growing, suggesting the prepared scaffold might be high potential for chondrogenesis.

Bioactivated collagen-based scaffolds embedding protein-releasing biodegradable microspheres: tuning of protein release kinetics

In tissue engineering, the recapitulation of natural sequences of signaling molecules, such as growth factors, as occurring in the native extracellular matrix (ECM), is fundamental to support the stepwise process of tissue regeneration. Among the manifold of tissue engineering strategies, a promising one is based on the creation of the chrono-programmed presentation of different signaling proteins. This approach is based upon the integration of biodegradable microspheres, loaded with suitable protein molecules, within scaffolds made of collagen and, in case, hyaluronic acid, which are two of the fundamental ECM constituents. However, for the design of bioactivated gel-like scaffolds the determination of release kinetics must be performed directly within the tissue engineering template. In this work, biodegradable poly(lactic-co-glycolic)acid (PLGA) microspheres were produced by the multiple emulsion-solvent evaporation technique and loaded with rhodamine-labelled bovine serum albumin (BSA-Rhod), a fluorescent model protein. The microdevices were dispersed in collagen gels and collagen-hyaluronic acid (HA) semi-interpenetrating networks (semi-IPNs). BSA-Rhod release kinetics were studied directly on single microspheres through confocal laser scanning microscopy (CLSM). To thoroughly investigate the mechanisms governing protein release from PLGA microspheres in gels, BSA-Rhod diffusion in gels was determined by fluorescence correlation spectroscopy (FCS), and water transport through the microsphere bulk was determined by dynamic vapor sorption (DVS). Moreover, the decrease of PLGA molecular weight and glass transition temperature (T(g)) were determined by gel permeation chromatography (GPC) and differential scanning calorimetry (DSC), respectively. Results indicate that protein release kinetics and delivery onset strongly depend on the complex interplay between protein transport through the PLGA matrix and in the collagen-based release media, and water sequestration within the scaffolds, related to the scaffold hydrophilicity, which is dictated by HA content. The proper manipulation of all these features may thus allow the obtainment of a fine control over protein sequential delivery and release kinetics within tissue-engineering scaffolds.

Photopatterned collagen–hyaluronic acid interpenetrating polymer network hydrogels

To engineer complex tissues, it is necessary to create hybrid scaffolds with micropatterned structural and biomechanical properties, which can closely mimic the intricate body tissues. The current report describes the synthesis of a novel photocrosslinkable interpenetrating polymeric network (IPN) of collagen and hyaluronic acid (HA) with precisely controlled structural and biomechanical properties. Both collagen and HA are present in crosslinked form in IPNs, and the two networks are entangled with each other. IPNs were also compared with semi-IPNs (SIPN), in which only collagen was in network form and HA chains were entangled in the collagen network without being photocrosslinked. Scanning electron microscopy images revealed that IPNs are denser than SIPNs, which results in their molecular reinforcement. This was further confirmed by rheological experiments. Because of the presence of the HA crosslinked network, the storage modulus of IPNs was almost two orders of magnitude higher than SIPNs. The degradation of the collagen–HA IPNs was slower than the SIPNs because of the presence of the crosslinked HA network. Increasing concentration of HA further altered the properties among IPNs. Cytocompatibility of IPNs was confirmed by Schwann cell and dermal fibroblasts adhesion and proliferation studies. We also fabricated patterned scaffolds with regions of IPNs and SIPNs within a bulk hydrogel, resulting in zonal distribution of crosslinking densities, viscoelasticities, water content and pore sizes at the micro- and macro-scales. With the ability to fine-tune the scaffold properties by performing structural modifications and to create patterned scaffolds, these hydrogels can be employed as potential candidates for regenerative medicine applications.

Development of hyaluronic acid-based scaffolds for brain tissue engineering

Three-dimensional biodegradable porous scaffolds play vital roles in tissue engineering. In this study, a hyaluronic acid–collagen (HA–Coll) sponge with an open porous structure and mechanical behavior comparable to brain tissue was developed. HA–Coll scaffolds with different mixing ratios were prepared by a freeze–drying technique and crosslinked with water-soluble carbodiimide to improve mechanical stability. The pore structure of the samples was evaluated by light and scanning electron microscopy, and the mechanical behavior was analyzed by mechanical compression and tension testing. The degree of crosslinking was determined by the water absorption and trinitrobenzene sulfonic assay, and the HA content was determined by a carbazole assay. The results showed that HA–Coll scaffolds containing an open porous structure with a homogeneous pore size distribution could be fabricated. Certain features of the mechanical properties of HA–Coll scaffolds prepared with a Coll:HA mixing ratio of 1:2, and pure HA sponges, were comparable with brain tissue. Neural stem cells (NSCs) were expanded in number in monolayer culture and then seeded onto the three-dimensional scaffolds in order to investigate the effects of the different types of scaffolds on neurogenic induction of the cells. This study contributes to the understanding of the effects of HA content and crosslink treatment on pore characteristics, and mechanical behavior essential for the design of HA–Coll scaffolds suitable for NSC growth and differentiation for brain tissue engineering.

The Procoagulant Properties of Hyaluronic Acid-Collagen (I)/Chitosan Complex Film

Biomaterial-induced human platelet activation remains one of the most crucial factors to determine the procoagulant properties of the biomaterial. In this experiment, a new type of biomacromolecule complex film (hyaluronic acid-collagen (I)/chitosan, HCC) was prepared using the electrostatic self-assembly method. Then the procoagulant properties of this complex film were characterized. Based on the nano-resolution of atomic force microscopy, the platelet-derived microparticles (PMPs) that present the activation of platelets were clearly visualized on the membrane surface of platelets for the first time, and the measurement indicated that the size of PMPs is around 50–110 nm. Furthermore, the results of AFM measurement were confirmed by flow cytometry analysis. The expression of CD62P (P-selectin) dramatically increased after the platelet-rich plasma interacted with the biomaterial solution. From the results, we could draw the conclusion that this biomacromolecule complex film has promising procoagulant properties, and has the potential to be practically used as procoagulant material.

The effect of different methods of cross-linking of collagen on its dielectric properties

This paper reports on the effect of different methods of collagen cross-linking on its dielectric properties. In order to obtain collagen–hyaluronic acid (HA) scaffolds, collagen was first dehydrated by a combination of thermal and vacuum drying (DHT) and then treated with the chemical reagent carbodiimide (EDC/NHS) for final cross-linking. The measurements of the relative permittivity ɛ′ and the dielectric loss ɛ″ for all materials were carried over the frequency range of 10 Hz–100 kHz and at temperatures from 22 to 260 °C. The results for these samples reveal distinct relaxation processes at low temperatures, below 140 °C and at higher temperatures as broad peak around 230 °C. The first and second relaxation are associated with changes in the secondary structure of collagen accompanied by the release of water and with the denaturation of dry collagen, respectively. The influence of cross-linking on the permittivity of collagen is significant over the entire temperature range.

Human Adipose Tissue-Derived Stem Cell Seeded Hyaluronic Acid-Collagen Scaffolds for Adipogenesis Investigated In Vivo

The purpose of this study is to confirm the possibility of regenerating actual fat tissue using human adipose tissue-derived stem cells (ASCs) and hyaluronic acid-collagen sponge in animal model. Human ASCs of young female adults were isolated and culture expanded in basal media. At the second passage, cultured ASCs suspension containing 106 cells was applied on prewetted scaffolds the hyaluronic acid-collagen sponge and the sponges was exposed to adipogenic media for the 1week. Then the tissue engineered constructs were implanted into the subcutaneous pocket on the back of immunodeficient athymic nude mice for 3 weeks. Hyaluronic acid-collagen sponges without human ASCs were used as the control. After 3 weeks, specimens were harvested and adipogenic potentials were assessed with histological examination, RT-PCR for PPAR-γ2 expression and G-3-PDH activity. Tissue engineered fat tissue from ASCs and hyaluronic acid-collagen sponges demonstrated PPAR-γ2 positive expression and positive Oil red O staining. The histologic study showed definitive adipose tissue and rich vascular tissue within the engineered fat. Two-fold higher activities of G-3-PDH were identified in experimental group after 3 weeks as compared to control. By contrast, the specimen from control group did not show active vessel ingrowth and contained only few cellular elements within the scaffold. The control specimens failed to demonstrate adipogenic gene markers and were negative in oil red O staining. In conclusion, human ASCs can be differentiated into adipocytes and actual fat tissue engineering was possible with combination of adequate scaffold materials, such as hyaluronic acid-collagen sponges. These data demonstrate that fat tissue engineered from human ASCs can retain predefined shape and dimension for soft tissue augmentation and reconstruction of defects.

Preparation and characterization of biodegradable anti-adhesive membrane for peritoneal wound healing

Postoperative adhesions remain a significant complication of abdominal surgery although the wide variety of physical barriers has been developed to reduce the incidence of adhesion. In this study, the bilayered composite membrane formed by the association of a methoxy poly (ethylene glycol)-poly (L-lactide-co-glycolide) (mPEG-PLGA) film and a crosslinked collagen-hyaluronic acid (Col-HA) membrane with fibronectin (FN) coating was prepared for promoting wound healing and providing tissue adhesion resistance simultaneously. In vitro adhesion test revealed that fibroblasts attached better on Col-HA membrane compared to those on mPEG-PLGA film, PLGA film or Interceed (oxidized cellulose) while mPEG-PLGA film had the lowest cell adhesive property. In confocal microscopic observation, the actin filaments were significantly further polymerized when 50 or 100 microg/cm(3) fibronectin was incorporated on the COL-HA membranes. After 7-day culture, fibroblasts penetrated throughout the Col-HA-FN network and the cell density increased whereas very few cells were found attached on the surface of the mPEG-PLGA film. In vivo evaluation test showed that the composite membrane could remain during the critical period of peritoneal healing and did not provoke any inflammation or adverse tissue reaction.