[Show abstract][Hide abstract] ABSTRACT: Surface coating of antifouling materials on the substrates offers convenient strategies and great opportunities to improve their biocompatibility and functions of host substrates for wide biomedical applications. In this work, we present a general surface zwitterionization strategy to improve surface biocompatibility and antifouling properties of titanium (Ti) by grafting zwitterionic poly(sulfobetaine methacrylate) (polySBMA). This method also demonstrates its general applicability to graft polySBMA onto Ti surface using different anchoring agents of dopamine and silane. The resulting polySBMA grafted from dopamine- (pTi-D-pSBMA) and silane-anchored titanium surfaces (pTi-Si-pSBMA) surfaces exhibit superlow fouling ability to highly resist the adhesions of plasma proteins, platelets, erythrocytes, leukocytes, human fibroblast (HT1080), E. coli and S. epidermidis. The interfacial properties of the surface-modified Ti surfaces are analyzed and correlated with their antifouling properties. The new method and materials provide a more general, flexible, and robust way to produce an excellent nonfouling surface with adjustable interfacial structures of grafted polymers, which hopefully can be expanded to a wider applications based on both the structure and surface superiorities.
[Show abstract][Hide abstract] ABSTRACT: The influence of the topographic morphology of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) films on human mesenchymal stem cells (hMSCs) was investigated in this study. PHBHHx films with various surface characteristics were prepared by compression-molding, solvent-casting and electrospinning. The adhesion, proliferation and differentiation behaviors of hMSCs were significantly modulated by the surface characteristics of these films. HMSCs could aggregate and form cellular clusters on the cast PHBHHx films, and the time to form cellular aggregates increased as the surface roughness increased. The aggregated hMSCs on the cast films kept their original surface markers and presented much higher viability during the regular culture and lower differentiation ability upon osteogenic induction than the spread cells on the compression-molded films and TCPS. HMSCs spread well and showed a specific orientation on the surface of the random electrospun fibrous films, they were not able to migrate into the interior of electrospun fibrous films, and they revealed the highest viability during the regular culture but a lower differentiation activity upon osteogenic induction. The electrospun fibrous PHBHHx films could serve as a suitable substrate for large quantity culturing of hMSCs when undifferentiated hMSCs are desired.
[Show abstract][Hide abstract] ABSTRACT: Polyhydroxyalkanoates (PHAs) are a newer family of biomaterials for tissue-engineering applications. The objective of this study is to investigate the behavior of human mesenchymal stem cells (hMSCs) grown on various PHA films. The surface characteristics of PHA co-polymer films were varied by the content of 3-hydroxyvalerate (HV) or 3-hydroxyhexanoate (HHx) and by the film preparation methods such as compression-molding and solvent-casting. Hyaluronic acid (HA) was further applied to modify the surface properties of PHA membranes. As HV content increased, the crystallinity and the hydrophobicity of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) membranes decreased and the metabolic activity of hMSCs raised, although the distribution and morphology of hMSCs did not show significant variation. Hyaluronic acid (HA) coating on PHA membranes could improve the metabolic activity and reduce the death rate of hMSCs. Aggregates and spheroidal clusters of hMSCs were found on the surface of cast poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) membranes. The growth of hMSCs was remarkably influenced by various surface characteristics of the PHA films.
[Show abstract][Hide abstract] ABSTRACT: The aim of this study was to evaluate the behaviors of mesenchymal stem cells (MSCs) on Poly(L-Lactic acid) (PLLA) membranes with different surface topographies. The double-sided micropatterns, island-patterned, and sunken-patterned PLLA membranes with diameters of 60 and 100 microm, were fabricated by the soft lithography method. The cell viability of MSCs on the island- and sunken-patterned PLLA membranes were characterized by scanning electron microscopy (SEM), MTT assay, and flow cytometric analysis. Cell adhesion and proliferation capability were superior for the MSCs seeding on the island-patterned PLLA membranes than those on the sunken-patterned PLLA membranes. Especially, we observed the best biocompatibility for MSCs on the island-patterned surface with diameter of 100 microm. In addition, the improvement of cell attachment and augmenting subsequent cellular response are investigated after the island-patterned membranes precoating with collagen and fibronectin. Furthermore, the flow cytometric analysis reveals the MSCs can expand and maintain the phenotype on these PLLA membranes without losing its potential for differentiation. Since scale-up of cell production and optimization of culture conditions are important for stem cell engineering, to control the stem cell proliferation and differentiation is necessary. Therefore, besides topographical properties play a crucial role on the stem cells attachment and proliferative activity, it is suggested that the "relative scale" between cell and pattern also affects the cell adhesion morphologies and cell behaviors. Based on the overall cellular response, this study provides a valuable guidance to prepare appropriate topographic surface for tissue engineering application.
Journal of Biomedical Materials Research Part A 12/2009; 91(3):929-38. DOI:10.1002/jbm.a.32309 · 3.37 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The aim of this study is to control the behavior of rat cerebellar granule neurons (rCGNs) by adjusting the surface characteristics of polyhydroxyalkanoate (PHA) films which were created by using compression-molding, solvent-casting, and electrospinning methods. The compression-molded PHA membranes were dense and flat substrates, the cast ones showed higher roughness than the compression-molded ones, and the electrospun membranes were fibrous substrates. RCGNs could aggregate into three-dimensional (3-D) spheroid and develop many synapses on the compression-molded and solvent-cast membranes, and they aggregated into two-dimensional (2-D) flat sheet on the electrospun film in contrast. The viability of rCGNs on the electrospun membranes was higher than that on the other PHA films because the nutrients and metabolizes could easily transport through the highly fibrous structure of the electrospun films. RCGNs did not respond to the environmental stimuli created by the surface characteristics of the compression-molded and solvent-cast films, while they showed obvious difference to the specific fibrous characteristics of electrospun film in terms of morphology and viability.
[Show abstract][Hide abstract] ABSTRACT: The new biodegradable polyester poly(3-hydroxybutyrate-co-3-hydroxyhexnoate) (PHBHHx) has a potential application in tissue engineering. The aim of this study was to present a deeper picture of the relationship between the cellular behavior and the surface characteristics of PHBHHx films. The pristine PHBHHx film was prepared by adopting the compression-molding method, and then the acrylic acid molecules were grafted on PHBHHx membrane surface by UV irradiation. The hydrophilic nature and surface roughness of various PHBHHx films were controlled by adjusting the acrylic acid concentration and the UV irradiation time. Although the surface characteristics of various PHBHHx films could not affect the metabolic activity of hMSCs, the performance of morphology of hMSCs was deeply affected by the hydrophilic nature and the orientation of surface scars. The hydrophilic nature would effectively improve the spread of hMSCs, and the orientation of surface scars would guide the growth direction of cytoskeleton (actin) inside hMSCs. In contrast, the behaviors of C3A/HepG2 hepatoma cells presented an opposite outcomes. Those surface characteristics were obviously associated with the performance of metabolic activity of C3A cells, but not with the morphology of C3A cells. Both hMSCs and C3A cells have unique cellular characteristics; therefore, their responses to environmental stimulations are significantly different.
[Show abstract][Hide abstract] ABSTRACT: Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) is a potential material for tissue engineering applications because of its excellent biodegradable and biocompatible properties. The aim of this study is to present a close picture of the interaction between human mesenchymal stem cells (hMSCs) and the surface characteristics of PHBHHx membranes. The surface characteristics of PHBHHx membranes were created by using compression-molding, solvent-casting, and electrospinning methods. The behaviors of the hMSCs performed differently on those membranes. The highly porous electrospun PHBHHx membranes are better substrates for culturing hMSCs as they can keep higher cell viability than the compression-molded PHBHHx membranes. Aggregation and cluster formation of hMSCs were found only on the cast PHBHHx membranes.
[Show abstract][Hide abstract] ABSTRACT: The influence of the properties and surface micropatterning of chitosan-collagen-gelatin (CCG) blended membranes on C3A cell's activities has been investigated. It is aimed to guide the cell growth and improve the growth rate in vitro for the application in tissue engineering. Masters with micropatterns are prepared on stainless steel plates by photolithography. The CCG membranes with surface micropatterns are then fabricated by soft lithography and dry-wet phase inversion techniques. The morphology and metabolic activity of cultured C3A cells on the membranes are recorded. When the C3A cells are seeded on the membranes with micropattern spacing of 200 microm width and 80 microm depth, they adhere and aggregate in the groove of the membranes in a few minutes. The aggregated cells migrate up to the surface of the ridge later. This phenomenon, however, is not found on membranes with a micropattern spacing of 500 microm width. In addition, it is demonstrated that the cells on the CCG membranes with micropatterns have higher metabolism and growth rates than those on the flat CCG membranes and on T-flask discs. Micropatterning on the membrane surface can affect the distribution of cells and the communication among cells, and results in a difference in cell adhesion, morphology, mobility, and growth activity.
[Show abstract][Hide abstract] ABSTRACT: Copolymers of 3-hydroxyvalerate (HV) and 3-hydroxyhexanoate (HHx) membranes are a new family of biomaterials for tissue engineering applications. The object of this study is to investigate the behavior of rat tooth germ cells on various 3-hydroxyl-butyrate-co-3-hydroxy-hexanoate (PHBHHx) membranes. In this study, PHBHHx membranes from three thin-film processes were used. PHBHHx membranes with different surface morphologies were prepared by phase inversion, electrospinning, and hot pressing. The morphologies of the PHBHHx membranes were investigated by scanning electron microscopy (SEM). Tooth germ cells were isolated from four-day-old Wistar rats. The cellular adhesion, proliferation and viability were determined by SEM, BrdU (5-bromo-2-deoxyuridine) and MTT (3-[4, 5-Dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide; Thiazolyl blue) assay. In addition, the adherent behavior of tooth germ cells on various surface structures of PHBHHx was observed under a fluorescence microscope after staining of the cytoskeletal filamentous actin of the cells. It was found that cell compatibility of the PHBHHx membranes made from the phase inversion method (p-PHBHHx) was better than that of the other PHBHHx membranes. The results also revealed that tooth germ cells cultured on the PHBHHx membranes with porous surface structure were well spread relative to those on the fibrous structure of PHBHHx membranes. Therefore, PHBHHx membranes with a porous surface structure can encourage either cell adhesion or cell proliferation. PHBHHx membranes with a porous morphology satisfy biomaterial requirements for a scaffold for tooth regeneration.
[Show abstract][Hide abstract] ABSTRACT: Polyhydroxyalkanoates (PHAs) is a newer family of biomaterials for tissue engineering applications. The objective of this study is to investigate the behaviors of human Schwann cells-like (hSCs-like) on various PHA films. The surface characteristics of PHA films were varied by the content of 3-hydroxyvalerate (HV) or 3-hydroxyhexanoate (HHx) and by the film preparation methods such as compression-molding and solvent-casting. Hyaluronic acid (HA) and poly(L-lysine) (PLL) were further applied on to improve the growth of hSCs-like on PHA membranes. The hSCs-like isolated from human body (MATERIALS AND METHODS) would have strong metabolic activities and produce many extracellular matrix (ECM). When HV content increased, there was a reduction in the crystallinity and the hydrophoicity of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) membranes. Despite that these different surface characteristics did not show significant effect on the metabolic activities of hSCs-like, these would affect adhering HA. Hyaluronic acid (HA)-coated PHA membranes could improve the metabolic activities and decrease the death ratio of hSCs-like. However, the condition of PLL coating has no obvious influence on the activities of hSCs.
[Show abstract][Hide abstract] ABSTRACT: The influence of surface micropatterning of the chitosan–collagen–gelatin (CCG) blended membranes on the activities of human mesenchymal stem cells (hMSCs) has been investigated. It is aimed to regulate the growth activity in vitro and to guide the spatial arrangement of hMSCs on the membranes for the application in tissue engineering. Masters with micropatterns were prepared on stainless steel plates or silicon wafer by photolithography. The CCG membranes with topological surface micropatterns were then fabricated by soft-lithography. The morphology and growth activity of hMSCs on the membranes were recorded. When MSCs were seeded on the membranes with micropattern spacing size of 200μm in width and 80μm in depth, they adhered and aggregated in the grooves of the membranes in a few minutes. The aggregated cells would migrate up to the surface of the ridge later, and the cells on the ridge align with the direction of the ridge-groove patterns. Some of the cells would form bridge-like structure between two adjacent ridges. When the pattern spacing size was smaller than the size of cell, the proliferation of hMSCs would be limited. Micropatterning on membrane surface could affect the distribution of hMSCs and resulted in difference of cell behaviors such as cell alignment, morphology, proliferation, and growth activity.