Biomimetic surface modification of poly(L-lactic acid) with chitosan and its effects on articular chondrocytes in vitro

The objective of this study was to investigate the efficiency of two treatments for poly(L-lactic acid) (PLLA) surface modification with chitosan, via entrapment and coupling by using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide. The properties of original PLLA films, chitosan-entrapped and coupled PLLA films were investigated by water contact angle measurement and electron spectroscopy for chemical analysis (ESCA). The contact angle indicated the change in hydrophilicity and the ESCA data suggested that the modified PLLA films became enriched with nitrogen atoms. The cytocompatibility of modified PLLA films might be improved. Therefore, the attachment and proliferation of bovine articular chondrocyte seeded on modified PLLA films and control one were examined. A whole cell enzyme-linked immunosorbent assay (Cell ELISA) that detects the BrdU incorporation during DNA synthesis and collagen type II secretion was applied to evaluate the chondrocytes on different PLLA films and tissue culture plates. Cell viability was estimated by the MTT assay and cell function were assessed by measuring sulfated glycosaminoglycan secreted by chondrocytes. These results implied that chitosan used to modify PLLA surface through entrapment and coupling could enhance the chondrocyte adhesion, proliferation and function.     

Biomimetic surface modification of poly (L-lactic acid) with gelatin and its effects on articular chondrocytes in vitro

Our objective in this study was to investigate the efficiency of two treatments for poly (L-lactic acid) (PLLA) surface modification with gelatin, via entrapment and coupling, using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) and N-hydroxysuccinimide (NHS). The properties of original PLLA, gelatin-entrapped, and coupled PLLA films were investigated by water contact angle measurement and electron spectroscopy for chemical analysis (ESCA). The water contact angle indicated that the incorporation of gelatin resulted in a change in hydrophilicity, and the ESCA data suggested that the modified PLLA films became enriched with nitrogen atoms. The cytocompatibility of modified PLLA films might be improved. Therefore, we examined the attachment and proliferation of bovine articular chondrocyte seeded on modified PLLA films and virgin films. A whole-cell enzyme-linked immunosorbent assay (cell ELISA) that detects 5-bromo-2'-deoxyuridine (BrdU) incorporation during DNA synthesis and collagen type II secretion was applied to evaluate the chondrocytes on different PLLA films and tissue culture plates (TCPS). Cell viability was estimated by the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] assay, and cell function was assessed by measuring glycosaminoglycan (GAG) secreted by chondrocytes. These results implied that gelatin used to modify the PLLA surface through entrapment and coupling could enhance chondrocyte adhesion, proliferation, and function.     

Fabrication and characterization of PLLA-chitosan hybrid scaffolds with improved cell compatibility

To combine the individual advantages of synthetic and natural polymers, poly(L-lactic acid) (PLLA)-chitosan hybrid scaffolds were fabricated. PLLA sponges were prepared by particulate-leaching, and then PLLA-chitosan hybrid scaffolds were obtained by dipping the PLLA sponges in chitosan solution and subsequently freeze-drying. Physicochemical properties of the scaffolds were characterized by scanning electron microscopy (SEM), water uptake test, and mechanical strength measurement. Moreover, cell adhesion, cell proliferation, and cell viability on the scaffolds were evaluated through osteoblast-like cell culture. The experimental results indicated that, PLLA sponges exhibited macroporous structure and the interconnected microporous structure of chitosan was formed within the macropores of PLLA sponges. The incorporation of chitosan reinforced PLLA sponges in dependence on chitosan content. The hybrid scaffolds had higher water uptake ability compared with PLLA sponges. Particularly, the hybrid scaffolds exhibited excellent cell attachment efficiency, cell proliferation, and cell viability. This study suggests that the hybrid scaffolds obtain good mechanical strength from PLLA and excellent cell compatibility from chitosan.     

Polyurethane/nano-hydroxyapatite composite films as osteogenic platforms

A wide variety of biomaterials are utilized in tissue engineering to promote cell proliferations in vitro or tissue growth in vivo. The combination of cells, extracellular matrices, and biocompatible materials may make it possible to grow functional living tissues ranging from bone to nerve cells. In bone regeneration, polymeric scaffolds can be enhanced by the addition of bioactive materials. To this end, this study designed several ratios of polyurethane (PU) and nano-hydroxyapatite (nHA) composites (PU-nHA ratios: 100/0, 90/10, 80/20, 70/30, 60/40 w/w). The physical and mechanical properties of these composites and their relative cellular compatibility in vitro were determined. The chemical composition and crystallinity of the composites were confirmed using X-ray diffraction, X-ray photoelectron spectroscopy, and thermogravimetric analyses. Atomic force microscopy, nano-indentation, and contact angle measurements were used to evaluate surface properties. The results showed a significant increase in surface roughness and a decrease in contact angle when the nHA concentration increased above 20%, resulting in a significant increase in hydrophilicity. These surface property changes influenced cellular behavior when MC 3T3-E1 cells were seeded on the composites. All composites were cytocompatible. There was a linear increase in cell proliferation on the 80/20 and 70/30 composites only, whereas subjective evaluation demonstrated noticeable clusters or nodules of cells (considered hallmarks of osteogenic differentiation) in the absence of any osteogenic inducers only on the 90/10 and 80/20 composites. Cellular data suggests that the 80/20 composite was an optimal environment for cell adhesion, proliferation, and, potentially, osteogenic differentiation in vitro.     

Adhesion and proliferation of OCT-1 osteoblast-like cells on micro- and nano-scale topography structured poly(L-lactide)

The impact of the surface topography of polylactone-type polymer on cell adhesion was to be concerned because the micro-scale texture of a surface can provide a significant effect on the adhesion behavior of cells on the surface. Especially for the application of tissue engineering scaffold, the pore size could have an influence on cell in-growth and subsequent proliferation. Micro-fabrication technology was used to generate specific topography to investigate the relationship between the cells and surface. In this study the pits-patterned surfaces of polystyrene (PS) film with diameters 2.2 and 0.45 microm were prepared by phase-separation, and the corresponding scale islands-patterned PLLA surface was prepared by a molding technique using the pits-patterned PS as a template. The adhesion and proliferation behavior of OCT-1 osteoblast-like cells morphology on the pits- and islands-patterned surface were characterized by SEM observation, cell attachment efficiency measurement and MTT assay. The results showed that the cell adhesion could be enhanced on PLLA and PS surface with nano-scale and micro-scale roughness compared to the smooth surfaces of the PLLA and PS. The OCT-1 osteoblast-like cells could grow along the surface with two different size islands of PLLA and grow inside the micro-scale pits of the PS. However, the proliferation of cells on the micro- and nano-scale patterned surface has not been enhanced compared with the controlled smooth surface.     

Effects of oxygen plasma treatment on adipose-derived human mesenchymal stem cell adherence to poly(L-lactic acid) scaffolds

Plasma treatment of substrate surfaces can be utilized to improve adhesion of cells to tissue-engineered scaffolds. The purpose of this study was to enhance cell adhesion to non-woven poly(L-lactic acid) (PLLA) scaffolds using oxygen plasma treatment to increase surface hydroxyl groups and thereby enhance substrate hydrophilicity. It was hypothesized that oxygen plasma treatment would increase the number of adipose-derived human mesenchymal stem cells (hMSCs) that adhered to melt-blown, non-woven PLLA scaffolds without affecting cell viability. The number of cells that adhered to the oxygen plasma-treated (10 min at 100 W) or untreated PLLA scaffolds was assessed at 2, 4, 8, 12, 24 and 48 h post-seeding via DNA analysis. Cell viability and morphology were also assessed at 2, 4, 8, 12 and 24 h post-seeding via a live/dead assay and hematoxylin staining, respectively. Oxygen plasma treatment decreased the contact angle of water from 75.6° to 58.2°, indicating an increase in the surface hydrophilicity of PLLA. The results of the DNA analysis indicated that there was an increased number of hMSCs on oxygen plasma treated scaffolds for two of the three donors. In addition, oxygen plasma treatment promoted a more even distribution of hMSCs throughout the scaffold and enhanced cell spreading at earlier time points without altering cell viability. This early induction of cell spreading and the uniform distribution of cells, in turn, may increase future proliferation and differentiation of hMSCs under conditions that simulate the microenvironment in vivo.     

The biological response of poly(L-lactide) films modified by different biomolecules: role of the coating strategy

The interactions between the surface of synthetic scaffolds and cells play an important role in tissue engineering applications. To improve these interactions, two strategies are generally followed: surface coating with large proteins and surface grafting with small peptides. The proteins and peptides more often used and derived from the extracellular matrix, are fibronectin, laminin, and their active peptides, RGD and SIKVAV, respectively. The aim of this work was to compare the effects of coating and grafting of poly(L-lactide) (PLLA) films on MRC5 fibroblast cells. Grafting reactions were verified by X-ray photoelectron spectroscopy. Cell adhesion and proliferation on coated and grafted PLLA surfaces were measured by cell counting. Vinculin localization and distribution were performed on cell cultured on PLLA samples using a fluorescence microscopy technique. Finally, western blot was performed to compare signals of cell adhesion proteins, such as vinculin, Rac1, and RhoA, as well as cell proliferation, such as PCNA. These tests showed similar results for fibronectin and laminin coated PLLA, while RGD grafting is more effective compared with SIKVAV grafting. Considering the overall view of these results, although coating and grafting can both be regarded as effective methods for surface modification to enhance cell adhesion and proliferation on a biomaterial, RGD grafted PLLA show better cell adhesion and proliferation than coated PLLA, while SIKVAV grafted PLLA show similar adhesion but worse proliferation. These data verified different biological effects depending on the surface modification method used.     

Effect of Ammonia Plasma Treatment on the Properties and Cytocompatibility of a Poly(L-Lactic Acid) Film Surface

Ammonia plasma treatment is an efficient method to modify the surface of polymeric biomaterials to improve their hydrophilicity and biocompatibility. In this study, poly(L-lactic acid) (PLLA) films were treated with ammonia plasma to investigate the effects on the surface properties and cytocompatibility. Surface morphologies of the films were observed with atomic force microscopy (AFM) and the surface roughness was analyzed with the software attached to the AFM. Mass loss density and contact angles associated to plasma treatment power and time were also studied. The stability of the treated films was evaluated by testing the contact angle change. The cytocompatibiliy was evaluated by cell adhesion, proliferation and cell cycle. The results showed that the surface morphology and roughness of the treated PLLA surfaces increased with treatment power. The mass loss density increased with plasma treatment power and time. With increasing treatment power and time, the resulting amino group density on treated PLLA film surface increased first and decreased later, while the contact angle showed an opposite trend. The contact angle of the treated films increased with storage time and returned to its original value after about 2 weeks. The cell experiments indicated that promotion of cell adhesion and proliferation were significantly improved on the treated PLLA surfaces.     

Plasma modification of PMMA films: surface free energy and cell-attachment studies

The surface of a material is the most important part determining the acceptance by and compatibility with the environment. In many cases, although the bulk properties are excellent for a specific application, the surface may require to be modified and engineered in the desired direction. This is especially important for materials used in biological media, since the surface charge, hydophilicity and wettability are important for thrombosis formation, cell attachment or cell proliferation. In this study, poly(methyl methacrylate) films were prepared by solvent casting and their surfaces were modified by oxygen plasma treatment by applying powers of 20, 100 and 300 W. The effects of surface chemistry alterations on hydophilicity, work of adhesion, surface free energy and cell adhesion were examined. Cell attachment and proliferation are especially important for the materials used for tissue-engineering purposes. The results demonstrated that there is an optimum value for hydrophilicity and surface free energy which enhance cell attachment.     

Plasma modification of PMMA films: surface free energy and cell-attachment studies

The surface of a material is the most important part determining the acceptance by and compatibility with the environment. In many cases, although the bulk properties are excellent for a specific application, the surface may require to be modified and engineered in the desired direction. This is especially important for materials used in biological media, since the surface charge, hydophilicity and wettability are important for thrombosis formation, cell attachment or cell proliferation. In this study, poly(methyl methacrylate) films were prepared by solvent casting and their surfaces were modified by oxygen plasma treatment by applying powers of 20, 100 and 300 W. The effects of surface chemistry alterations on hydophilicity, work of adhesion, surface free energy and cell adhesion were examined. Cell attachment and proliferation are especially important for the materials used for tissue-engineering purposes. The results demonstrated that there is an optimum value for hydrophilicity and surface free energy which enhance cell attachment.     

Mechanical enhancement and in vitro biocompatibility of nanofibrous collagen-chitosan scaffolds for tissue engineering

The collagen–chitosan complex with a three-dimensional nanofiber structure was fabricated to mimic native ECM for tissue repair and biomedical applications. Though the three-dimensional hierarchical fibrous structures of collagen–chitosan composites could provide more adequate stimulus to facilitate cell adhesion, migrate and proliferation, and thus have the potential as tissue engineering scaffolding, there are still limitations in their applications due to the insufficient mechanical properties of natural materials. Because poly (vinyl alcohol) (PVA) and thermoplastic polyurethane (TPU) as biocompatible synthetic polymers can offer excellent mechanical properties, they were introduced into the collagen–chitosan composites to fabricate the mixed collagen/chitosan/PVA fibers and a sandwich structure (collagen/chitosan-TPU-collagen/chitosan) of nanofiber in order to enhance the mechanical properties of the nanofibrous collagen–chitosan scaffold. The results showed that the tensile behavior of materials was enhanced to different degrees with the difference of collagen content in the fibers. Besides the Young’s modulus had no obvious changes, both the break strength and the break elongation of materials were heightened after reinforced by PVA. For the collagen–chitosan nanofiber reinforced by TPU, both the break strength and the Young’s modulus of materials were heightened in different degrees with the variety of collagen content in the fibers despite the decrease of the break elongation of materials to some extent. In vitro cell test demonstrated that the materials could provide adequate environment for cell adhesion and proliferation. All these indicated that the reinforced collagen–chitosan nanofiber could be as potential scaffold for tissue engineering according to the different mechanical requirements in clinic.     

Promotion of initial anti-tumor effect via polydopamine modified doxorubicin-loaded electrospun fibrous membranes

Drug-loaded electrospun PLLA membranes are not conducive to adhesion between materials and tissues due to the strong hydrophobicity of PLLA, which possibly attenuate the drugs’ effect loaded on the materials. In the present work, we developed a facile method to improve the hydrophilicity of doxorubicin (DOX)-loaded electrospun PLLA fibrous membranes, which could enhance the anti-tumor effect at the early stage after implantation. A mussel protein, polydopamine (PDA), could be easily grafted on the surface of hydrophobic DOX-loaded electrospun PLLA membranes (PLLA-DOX/pDA) in water solution. The morphology analysis of PLLA-DOX/pDA fibers displayed that though the fiber diameter was slightly swollen, they still maintained a 3D fibrous structure, and the XPS analysis certified that pDA had successfully been grafted onto the surface of the fibers. The results of surface wettability analysis showed that the contact angle decreased from 136.7° to 0° after grafting. In vitro MTT assay showed that the cytotoxicity of PLLA-DOX/pDA fibers was the strongest, and the stereologic cell counting assay demonstrated that the adhesiveness of PLLA/pDA fiber was significantly better than PLLA fiber. In vivo tumor-bearing mice displayed that, after one week of implantation, the tumor apoptosis and necrosis of PLLA-DOX/pDA fibers were the most obvious from histopathology and TUNEL assay. The caspase-3 activity of PLLA-DOX/pDA group was the highest using biochemical techniques, and the Bax: Bcl-2 ratio increased significantly in PLLA-DOX/pDA group through qRT-PCR analysis. All the results demonstrated that pDA can improve the affinity of the electrospun PLLA membranes and enhance the drug effect on tumors.     

Surface modification of poly(L-lactic acid) by entrapment of chitosan and its derivatives to promote osteoblasts-like compatibility

Surface modification of biomaterials has been adopted over the years to improve their biocompatibility. In this study, aiming to promote hydrophilicity and to introduce natural recognition sites onto poly(L-lactic acid) (PLLA) films, chitosan and its derivatives, carboxymethyl chitosan (CMC) and N-methylene phosphonic chitosan (NPC), were used to modify the surface of PLLA films by an entrapment method. The surface properties of original and modified PLLA films were measured by using water contact angle measurement and X-ray photoelectron spectroscopy (XPS). Subsequently, the cytocompatibility of these PLLA films was investigated by testing osteoblasts-like cytocompatibility, cell attachment, cell proliferation, alkaline phosphatase activity, and cell cycle. Experimental results indicated that the hydrophilicity of the modified films was improved and the surface of the modified PLLA films became enriched with chitosan and its derivatives. Moreover, the surface modification with chitosan and its derivatives significantly promoted osteoblasts-like compatibility of PLLA films. This surface modification, combining the individual advantages of PLLA with good mechanical property and chitosan as well as its derivatives with good cytocompatibility, is a promising method to prepare desirable biomaterials.     

Hydrophilic nanofibrous structure of polylactide; fabrication and cell affinity

Microstructure and architecture of the scaffolds along with the surface chemistry exert profound effect on biological activity (cell distribution, proliferation, and differentiation). For the biological activity, scaffolds in tissue engineering have been widely designed. The objective of this study was to develop hydrophilic nanofibrous structure of polylactides (PLLA) polymer in the form of nonwoven mat by electrospinning technique, and further evaluate the fibroblast NIH3T3 cell proliferation, morphology, and cell-matrix interaction. Hydrophilicity of the PLLA fibers was improved by adding small fraction of low molecular weight polyethylene glycol (PEG) into the electrospinning solution. Four different ratio types (100/0, 80/20, 70/30, and 50/50) of PLLA/PEG electrospun matrices were fabricated, and the pore characteristics, tensile properties, contact angle, and hydrolytic degradation were observed. Furthermore, scanning electron microscope (SEM) and fluorescence actin staining images were used for micro-observation of cell-matrix interaction and cell morphology. It was found that the electrospun mat of PLLA/PEG (80/20), composed of fibers with diameters in the range 540-850 nm, majority of pore diameter less than 100 microm, tensile strength 8 MPa, elongation 150%, porosity more than 90%, and improved hydrophilicity with slow hydrolytic degradation, is favorable for biological activity of NIH3T3 fibroblast cell. Based on these results, the correct composition of PLLA and PEG in the porous electrospun matrix (i.e., PLLA/PEG (80/20)) will be a better candidate rather than other compositions of PLLA/PEG as well as hydrophobic PLLA for application in tissue engineering.     

Fabrication and characterization of chitosan/OGP coated porous poly(ε-caprolactone) scaffold for bone tissue engineering

As one of the stimulators on bone formation, osteogenic growth peptide (OGP) improves both proliferation and differentiation of the bone cells in vitro and in vivo. The aim of this work was the preparation of three dimensional porous poly(ε-caprolactone) (PCL) scaffold with high porosity, well interpore connectivity, and then its surface was modified by using chitosan (CS)/OGP coating for application in bone regeneration. In present study, the properties of porous PCL and CS/OGP coated PCL scaffold, including the microstructure, water absorption, porosity, hydrophilicity, mechanical properties, and biocompatibility in vitro were investigated. Results showed that the PCL and CS/OGP-PCL scaffold with an interconnected network structure have a porosity of more than 91.5, 80.8%, respectively. The CS/OGP-PCL scaffold exhibited better hydrophilicity and mechanical properties than that of uncoated PCL scaffold. Moreover, the results of cell culture test showed that CS/OGP coating could stimulate the proliferation and growth of osteoblast cells on CS/OGP-PCL scaffold. These finding suggested that the surface modification could be a effective method on enhancing cell adhesion to synthetic polymer-based scaffolds in tissue engineering application and the developed porous CS/OGP-PCL scaffold should be considered as alternative biomaterials for bone regeneration.     

Effects of oxygen plasma treatment on adipose-derived human mesenchymal stem cell adherence to poly(L-lactic acid) scaffolds

Plasma treatment of substrate surfaces can be utilized to improve adhesion of cells to tissue-engineered scaffolds. The purpose of this study was to enhance cell adhesion to non-woven poly(L-lactic acid) (PLLA) scaffolds using oxygen plasma treatment to increase surface hydroxyl groups and thereby enhance substrate hydrophilicity. It was hypothesized that oxygen plasma treatment would increase the number of adipose-derived human mesenchymal stem cells (hMSCs) that adhered to melt-blown, non-woven PLLA scaffolds without affecting cell viability. The number of cells that adhered to the oxygen plasma-treated (10 min at 100 W) or untreated PLLA scaffolds was assessed at 2, 4, 8, 12, 24 and 48 h post-seeding via DNA analysis. Cell viability and morphology were also assessed at 2, 4, 8, 12 and 24 h post-seeding via a live/dead assay and hematoxylin staining, respectively. Oxygen plasma treatment decreased the contact angle of water from 75.6 degrees to 58.2 degrees , indicating an increase in the surface hydrophilicity of PLLA. The results of the DNA analysis indicated that there was an increased number of hMSCs on oxygen plasma treated scaffolds for two of the three donors. In addition, oxygen plasma treatment promoted a more even distribution of hMSCs throughout the scaffold and enhanced cell spreading at earlier time points without altering cell viability. This early induction of cell spreading and the uniform distribution of cells, in turn, may increase future proliferation and differentiation of hMSCs under conditions that simulate the microenvironment in vivo.     

Surface modification of poly(<Emphasis Type="SmallCaps">l</Emphasis>-lactic acid) affects initial cell attachment,cell morphology,and cell growth

The object of this study was to develop a highly porous scaffold to be used in regeneration of blood vessels, nerves, and other hollow tissues with small openings. Using the phase-inversion method and a mixture of water and methanol as a coagulating agent, we prepared highly porous flat membranes from poly(l-lactic acid) (PLLA) with numerous pores both on the surface and in the interior of the membranes. Chinese hamster ovary (CHO) cells were cultured on the membranes to evaluate initial cell adhesion, cell proliferation, and cell morphology. Adhesion of CHO cells to PLLA was poor: the cells adhered at approximately half the rate observed with a tissue culture polystyrene dish (TCPS). In contrast, adhesion of cells to PLLA treated with a low-temperature oxygen plasma was good; the adhesion rate was the same as that on TCPS. The rate of cell proliferation on the treated membranes was no different from that on the nontreated membranes, but cell morphologies were quite different. The cells on the nontreated membranes were small and round and proliferated separately from one another. In contrast, the cells on the plasma-treated membranes proliferated in close contact with other cells, spreading out extensively in sheet-like formations. Since the plasma treatment not only accelerated cell adhesion but also enabled cells to proliferate in the form of sheets resembling biological tissue, we believe that oxygen-plasma treatment is extremely effective for modifying surfaces of materials used for tissue regeneration.     

Enhanced pH stability,cell viability and reduced degradation rate of poly(L-lactide)-based composite in vitro: effect of modified magnesium oxide nanoparticles

The modified MgO nanoparticles (m-MgO-NPs) by a copolymer containing the malic acid and low molecular weight poly(L-lactide) (poly(L-lactide-co-malic acid), PLMA) have been successfully prepared. MgO nanoparticles (MgO-NPs) were coated by the PLMA and m-MgO-NPs were uniformly dispersed in the PLLA matrix to a novel biocomposite material (PLLA/m-MgO-NPs) with more excellent interface bonding and uniformer dispersion, compared to the PLLA/MgO-NPs. Compared to neat PLLA and PLLA/MgO-NPs film, the m-MgO-NPs not only shown the obvious neutralization effect on the acidic solution in the degradation of the PLLA and better hydrophilicity, but also exhibited the higher cell viability and decrease the toxicity to the cell in the degradation process of PLLA in vitro. In addition, m-MgO-NPs also reduced the degradation rate of the PLLA. The mechanisms for the excellent dispersion of nanoparticles, enhanced pH stability, reduced degradation rate of the PLLA and the cell viability in vitro in the case of PLLA/m-MgO-NPs have also been proposed and discussed in detail.     

聚醚醚酮表面多孔羟基化改性对MC3T3-E1细胞黏附、增殖的影响

目的对聚醚醚酮(polyetheretherketone,PEEK)薄片表面进行多孔化和羟基化改性,观察PEEK表面形貌和生物活性的变化,并探讨该改性方法对前成骨MC3T3-E1细胞黏附、增殖的影响。方法超声波环境下浓硫酸处理PEEK表面,在其表面形成大量微孔结构;经湿化学法将PEEK表面的酮类基团还原成羟基基团,改善其表面化学活性,提升PEEK薄片的生物相容性。利用扫描电子显微镜(SEM)、傅里叶变换红外光谱仪(FTIR)及静态水接触角检测改性前后材料表面形貌、化学基团及亲水性的变化。未处理PEEK、多孔化PEEK、羟基化PEEK、多孔羟基化PEEK与MC3T3-E1细胞共培养,评价表面改性后PEEK薄片对细胞黏附、增殖的影响。结果 SEM结果显示浓硫酸处理后的PEEK薄片表面形成密集的空隙大小均匀的微孔结构,FT-IR结果证实羟基化改性成功地在PEEK表面还原出了大量羟基基团。同时,表面多孔化和羟基化改性均可有效提升PEEK材料表面的亲水性能。在体外细胞实验中,不同改性的PEEK材料与MC3T3-E1细胞共培养后结果显示,多孔化、羟基化和多孔羟基化改性均可显著促进细胞黏附和伸展,同时随着时间的延长,其促进细胞增殖的功能也逐步增强。结论表面多孔羟基化改性能有效提高PEEK材料表面的生物学活性和亲水性能,进而显著促进细胞的黏附和增殖。     

Fabrication of mineralized polymeric nanofibrous composites for bone graft materials

Poly-L-lactic acid (PLLA) and PLLA/collagen (50% PLLA+50% collagen; PLLA/Col) nanofibers were fabricated using electrospinning. Mineralization of these nanofibers was processed using a modified alternating soaking method. The structural properties and morphologies of mineralized PLLA and PLLA/Col nanofibers were investigated using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and contact angle measurements. Human bone-derived osteoblasts were cultured on the materials for up to 1 week to assess the biological properties of the nanofibrous composites. Cell attachment on these nanocomposites was also tested within 1 h of culture at room temperature. The mechanical properties of the cell-nanocomposite constructs were determined using tensile testing. From our results, the bone-like nano-hydroxyapatite (n-HA) was successfully deposited on the PLLA and PLLA/Col nanofibers. We observed that the formation of n-HA on PLLA/Col nanofibers was faster and significantly more uniform than on pure PLLA nanofibers. The n-HA significantly improved the hydrophilicity of PLLA/Col nanofibers. From the results of cell attachment studies, n-HA deposition enhanced the cell capture efficacy at the 20-minute time point for PLLA nanofibers. The E-modulus values for PLLA+n-HA with cells (day 1 and day 4) were significantly higher than for PLLA+n-HA without cells. Based on these observations, we have demonstrated that n-HA deposition on nanofibers is a promising strategy for early cell capture.