Shin-Hye Park

Preparation of Furfuryl-Fish Gelatin (F-f.gel) Cured Using Visible-Light and Its Application as an Anti-Adhesion Agent

AbstractAdhesions occurring on a variety tissues and operation sites are a serious side effect of surgery and may require additional surgery for removal. Therefore, Furfuryl-fish gelatin (F-f.gel) was synthesized by introducing a furan ring to fish gelatin for application as an anti-adhesion agent. F-f.gel was cured by visible-light irradiation, which changed the material from a solution to a film. The prepared F-f.gel was characterized by proton nuclear magnetic resonance spectroscopy (1H NMR), substitution ratio, gel permeation chromatography (GPC), methyl thiazolyl tetrazolium (MTT) assay, and tests for measuring photo immobilization, water contact angle (WCA), and cell attachment. The results showed that F-f.gel was effective as an anti-adhesion agent.

Photocurable O-Carboxymethyl Chitosan Derivatives for Biomedical Applications: Synthesis, In vitro Biocompatibility, and Their Wound Healing Effects

AbstractIn this work, photocurable water-soluble chitosan derivatives were prepared for biomedical applications by modifying water-soluble O-carboxymethyl chitosan (O-CMC) derivatives with furfuryl glycidyl ether (O-CMC/FGE). Successful derivatization of chitosan to the final product (O-CMC/FGE) was verified by UV and 1H NMR spectral analysis. The degree of photo-crosslinking was measured by a flow distance experiment after exposure to visible light for a certain period of time. The degree of crosslinking increased linearly in proportion to exposure time. The in vitro cell viability test revealed a lack of cytotoxicity of O-CMC/FGE against mouse 3T3 fibroblasts. However, poor cell attachment was observed for the cells seeded onto the photocured O-CMC/FGE; this is likely due to the anionic nature of this material. O-CMC/FGE displayed wound healing effects in an in vivo animal experiment using a burn wound model. Due to its good biocompatibility, wound healing effect, and mild cross-linking condition, together with an inhibitory effect on cell attachment, O-CMC/FGE would be a promising candidate as an anti-adhesion material for biomedical applications.

Wound healing effect of visible light-curable chitosan with encapsulated EGF

Low molecular O-carboxymethyl chitosan, a derivative of chitosan, was conjugated with a hydrophilic carboxymethyl group, following which the conjugate was modified with a furfuryl group. The chitosan derivative was cross-linked to encapsulate a model protein, bovine serum albumin (BSA), in the presence of Rose Bengal under visible light irradiation. The encapsulated BSA was slowly released from the matrix over 2 weeks. The modified chitosan exhibited antimicrobial activity and was non-cytotoxic to NIH3T3 fibroblasts. The wound healing effect of the cross-linked chitosan derivative was examined in Sprague-Dawley rats at 3, 7, and 14 days post-wounding. Cross-linked and murine epidermal growth factor (mEGF)-encapsulated chitosan derivatives healed wounds more rapidly in rats than non-encapsulated mEGF or chitosan derivative alone. Thus, visible light-curable chitosan has good potential for application as wound-healing matrix.

Preparation and in vivo evaluation of photo-cured O-carboxymethyl chitosan micro-particle for controlled drug delivery

Medical advances have prompted the research and development of biomaterials. Especially, chitosan has emerged as new generation of biomaterials because it beneficial properties as a natural polymer, such as less toxic, biodegradable, and biocompatible than synthetic ones. The prepared azidophenyl O-carboxymethyl chitosan (Az-O-CMC) was characterized by FTIR, 1H NMR and particle-size analyzer. The hardening rate and cross-linking maintenance of the Az-O-CMC were investigated with its irradiation time and concentration. A photo-mask was used for observation of photoimmobilization. 3T3-L1 cells were cultured to determine effect of cytotoxicity. Protein release test was conducted to evaluate the immobilizing effect. In addition, animal test was investigated for wound healing application. In this study, the results indicate that immobilization of protein with Az-O-CMC will be useful for medical application.

Preparation of photoreactive azidophenyl hyaluronic acid derivative: Protein immobilization for medical applications

AbstractPhotoreactive azidophenyl hyaluronic acid (Az-HA) derivative was synthesized to immobilize proteins such as epidermal growth factor (EGF) and bone morphogenetic protein (BMP). The photosensitizing group, 4-azidoaniline, was introduced to the carboxyl group of hyaluronic acid by a water soluble carbodiimide, 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC). To characterize the synthesized Az-HA, Fourier transform infrared (FTIR), proton nuclear magnetic resonance (1H NMR) and ultraviolet/visible (UV/vis) absorbance spectroscopy were performed. We demonstrated protein immobilization by using fluorescein isothiocyanate conjugated albumin (FITCBSA) on Az-HA derivative surfaces that were patterned with micro scale. Cytotoxicity and relative cell proliferation tests of the Az-HA derivative were performed on an MG-63 human osteoblast cell line for biocompatibility.

Enhancement effect of cell adhesion on titanium surface using phosphonated low-molecular-weight chitosan derivative

For improving cell adhesion on titanium surface, phosphonated low-molecular-weight chitosan (P-LMC) was prepared by introducing a phosphonate group of 4-phosphonobutyric acid to low-molecular-weight chitosan (3,000<MW<10,000). The phosphonate group of P-LMC was identified by 31P NMR. At about 30 ppm from external standard, there was a specific peak derived from phosphonate group. X-Ray Photoelectron Spectroscopy (XPS) and water contact angle were carried out for characterization of titanium surface treated with P-LMC. From these results, P-LMC coated on titanium surface was remained on that in spite of washing and P-LMC made titanium surface more hydrophilic. The biocompatibility of P-LMC was demonstrated through a cytotoxicity test using the C2C12 cell line because P-LMC should have no cytotoxicity for applying to dental implant materials. As a result, P-LMC was biocompatible to use as coating material of titanium. Improvement of cell adhesion on titanium surface treated with P-LMC was observed by microscopy, and the number of attached cells was counted using a hemocytometer. Titanium surface coated with P-LMC showed improved cell adhesion for 12 h. These results demonstrate that P-LMC is biocompatible and titanium surface treated with P-LMC has positive effects on cell adhesion. Therefore, P-LMC is a useful material that can be applied for titanium coating to enhance cell adhesion and osseointegration.

Nanolayer formation on titanium by phosphonated gelatin for cell adhesion and growth enhancement.

Phosphonated gelatin was prepared for surface modification of titanium to stimulate cell functions. The modified gelatin was synthesized by coupling with 3-aminopropylphosphonic acid using water-soluble carbodiimide and characterized by 31P nuclear magnetic resonance and gel permeation chromatography. Circular dichroism revealed no differences in the conformations of unmodified and phosphonated gelatin. However, the gelation temperature was changed by the modification. Even a high concentration of modified gelatin did not form a gel at room temperature. Time-of-flight secondary ion mass spectrometry showed direct bonding between the phosphonated gelatin and the titanium surface after binding. The binding behavior of phosphonated gelatin on the titanium surface was quantitatively analyzed by a quartz crystal microbalance. Ellipsometry showed the formation of a several nanometer layer of gelatin on the surface. Contact angle measurement indicated that the modified titanium surface was hydrophobic. Enhancement of the attachment and spreading of MC-3T3L1 osteoblastic cells was observed on the phosphonated gelatin-modified titanium. These effects on cell adhesion also led to growth enhancement. Phosphonation of gelatin was effective for preparation of a cell-stimulating titanium surface.

The applicability of furfuryl-gelatin as a novel bioink for tissue engineering applications: APPLICABILITY OF f-GELATIN AS A NOVEL BIOINK

Three-dimensional bioprinting is an innovative technique in tissue engineering, to create layer-by-layer structures, required for mimicking body tissues. However, synthetic bioinks do not generally possess high printability and biocompatibility at the same time. So, there is an urgent need for naturally derived bioinks that can exhibit such optimized properties. We used furfuryl-gelatin as a novel, visible-light crosslinkable bioink for fabricating cell-laden structures with high viability. Hyaluronic acid was added as a viscosity enhancer and either Rose Bengal or Riboflavin was used as a visible-light crosslinker. Crosslinking was done by exposing the printed structure for 2.5 min to visible light and confirmed using Fourier transform infrared spectroscopy and rheometry. Scanning electron microscopy revealed a highly porous networked structure. Three different cell types were successfully bioprinted within these constructs. Mouse mesenchymal stem cells printed within monolayer and bilayer sheets showed viability, network formation and proliferation (∼5.33 times) within 72 h of culture. C2C12 and STO cells were used to print a double layered structure, which showed evidence of the viability of both cells and heterocellular clusters within the construct. This furfuryl-gelatin based bioink can be used for tissue engineering of complex tissues and help in understanding how cellular crosstalk happens in vivo during normal or diseased pathology.