Papers by Keyword: Genipin

Abstract: Bacterial cellulose (BC) was synthesized using Gluconacetobacter xylinus (BCRC 14182). Synthesized BC was powdered and dissolved in Bis(ethylenediamine) copper (II) hydroxide (Cuen) solution to introduce the amine (NH₂) group onto the BC network to yield modified BC (mBC) which was then blended with poly (vinyl alcohol) (PVA) and subsequently crosslinked with genipin (Gp). Pristine, modified and crosslinked hydrogels were studied using Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and swelling behavior in water. FTIR revealed a distortion on the BC network chain via a reduction in the absorption of OH peak of mBC and the emergence of peaks at 1587 and 1560 cm^-1 attributed to N-H stretching of the induced NH₂ group. SEM confirmed the 3-D fibril and porous structure of BC which became distorted after modification and crosslinking. The hydrogels showed equilibrium water content of 86.5%, 67.5%, 66.7% and 33.0 % for BC, PVA, mBC-PVA and mBC-PVA-Gp, respectively. The decreased swelling in mBC-PVA-Gp indicated that genipin was able to crosslink the modified BC.

Abstract: Platelet-rich fibrin (PRF) was developed as a barrier membrane in periodontal regenerative therapy. It is known that PRF has a sustained released of growth factor and expected to facilitate the tissue regeneration. Since the PRF membranes have a rapid degradability (1-2 weeks), the regenerative therapy using a PRF membrane should be increased to reduce the degradability using a crosslinking agent which could provide resistance against enzymatic degradation. The aim of this study is to analyze the effect of 0.1% genipin as a crosslinking agent to degradability of PRF. PRF membranes were prepared from 20cc blood of healthy donors and immersed in 0.1% genipin solution as a test group and Phosphate Buffer Saline (PBS) solution as a control group for 2 hours and 72 hours. In order to evaluate degradability, the sample was subjected to 0.01% trypsin. Samples were weighed and the trypsin solution was refreshed every 24 hours. The difference weight represents enzymatic degradation. Degradation degree of sample PRF-crosslinked genipin 0.1% significantly decreased when it compared to the control group. Genipin reacts with primary amines in fibrin, performed a covalent coupling that improves the degradability resistance. This crosslink had to be effective to improve biomechanical properties of PRF as a membrane. This study demonstrated that 0.1% genipin as a crosslinking agent could reduce the degradation-degree of PRF.

Abstract: Carbonate apatite is one of the most widely studied bioceramic material for its use as bone cement. On the previous study, it has already stated that CO₃Ap cement has good osteoconductivity which makes this cement could be replaced by bone. However, the mechanical strength of CO₃Ap cement is still low. This low mechanical strength is estimated due to the high porosity and absence of organic components. The aim of this study is to improve the mechanical strength of the CO₃Ap cement reinforced by gelatin as an organic component with genipin as a cross-linking agent (Gelapin). The powder phase of vaterite and DCPA at weight ratio 40:60 were mixed with 0.2 mol/L Na₂HPO₄, 5% (w/v) gelatin, and 20% (v/v) genipin using 0.5 liquid to powder (L/P) ratio. The liquid phase ratios of Na₂HPO₄ and Gelapin were 50:50, 70:30, and 90:10. For control group, Gelapin were didn’t mixed in the liquid. Diametral tensile strength was improving and statistically significant (p<0.05) on set cement with 50:50 liquid ratio, the average value was 6.02 ± 0.14 MPa whereas the average value of the control group was only 3.10 ± 0.15 MPa. For this instance, gelatin serves a polymer matrix so the carbonate apatite crystallites could be well distributed within it which then gives more flexibility and resistance for the cement. On the other hand, genipin was also successfully cross-linked the gelatin. This study showed that by reinforcing CO₃Ap cement using genipin cross-linked gelatin might be a good candidate for a bone substitute material.

Abstract: The aim of this paper was to investigate the effects of cross-linked reaction on physicochemical properties of chitosan film by using genipin as cross-linker agent. Series of chitosan film samples with different amount concentration of genipin loaded (0-3 wt %) were prepared and characterized. The physicochemical properties of films were evaluated by Fourier Transform Infra-red (FTIR), UV-vis spectroscopy, Oxygen Transmission Rate (OTR), Scanning Electron Microscopy (SEM), water vapour and tensile test. The cross-linking reaction had affected on colour changing of chitosan film samples from light yellow to dark blue in line with the increasing of genipin concentration. Thus, UV-vis spectroscopy on the cross-linked samples showed the absorbance value at 600 nm wavelength due to genipin content. FTIR observation on cross-linked film samples showed no characteristic of –OCH₃ peak from genipin at 1444 cm^-1 which resulted by new covalent bonding occurred between chitosan and genipin. Cross-linking also had increased the oxygen barrier and reduced the water vapor rate through the film. Chitosan film sample with addition of 1 wt% genipin achieved the highest tensile stress average at 49.46 MPa compared to other samples while percent of elongation at break reduced with the increasing of genipin concentration loaded

Abstract: The aim of this study was to investigate the effects of covalent and ionic cross-linked reactions which were respectively done by using genipin and tripolyphosphate (tpp), on the structure and mechanical properties of chitosan film. Both cross-linked and uncross-linked films were prepared by solution casting method and characterized. FTIR spectra showed no characteristic of –OCH₃ peak from genipin at 1444 cm^-1 which resulted by a new covalent bonding in chitosan film. Reduction in absorption intensity at 1560 cm^-1 wave number in chitosan cross-linked tpp films were due to the presence of ionic interaction between the positive charged of amino group in chitosan and negatively charged of phosphate group by tpp. The pattern area from the XRD results showed that the covalent cross-linked had significantly changed on the chitosan`s degree of crystallinity. The water contact angle on the surface of covalent/ionic cross-linked chitosan film reached the highest θ at 82.72° which indicated more hydrophobic properties was formed. Covalent/ionic cross-linked chitosan also showed the higher mechanical strength with average tensile stress value at 71.25 MPa. All finding results demonstrated that cross-linked modification on the chitosan film had successfully reduced the film’s hydrophilicity and increased the mechanical properties of the film.

Abstract: Currently researchers has pointed chitosan as one of the viable alternatives for application as scaffolds in tissue regeneration, mainly due to its availability, biocompatibility, biodegradability and ability to chemical modifications, among them, the crosslinking. With the growing number of investigations of crosslinking agents from natural sources and its applicability, this work focuses on the development and microstructural characterization of chitosan scaffolds and chitosan crosslinked with genipina using the technique of freeze drying. Solutions were prepared with chitosan concentration of 2% (w / t), and genipin 0.15% (w / t) and 0.3% (w / t). These were frozen at-20 ° C and ≈ 196 ° C, and lyophilized. The effect of different concentrations of genipin and freezing rates of the solutions in the porous architecture of the scaffolds were evaluated by Scanning Electron Microscopy (SEM), Optical Digital Microscopy 2D and 3D (OM) and testing the Degree of Swelling (DS). The SEM analysis revealed the formation of a three dimensional structure with pores and / or channels interconnected, influenced by the freezing rate and addition of crosslinking agent, these variables also influence the absorption capacity of the scaffolds. It was observed by OM, the effectiveness of the crosslinking with genipin, through points of fluorescence presented.

Abstract: The significance of studying of human pericardial mechanics arises from a wide range of possible applications. For instance, tissue engineers study potential use of a human pericardium in a design of homograft valve bioprosthesis. In cooperation with the Institute of the Physiology of Academy of Sciences of the Czech Republic, human pericardium tissue has been modified by different cross-linking agents. The function and performance of the potential future bioprostheses depends closely on sources material. Thus characterization of the mechanical properties of the human pericardial tissue is an important problem. Several samples of pericardial tissue as well as cross-linked tissue underwent uniaxial loading and unloading. Their nonlinear mechanical response was modeled using hyperelastic theory, assuming incompressible isotropic deformation. Considering future possible tissue application, mechanical properties of the material under stress corresponding to the loading in aortic valve were evaluated.

Abstract: In this paper, the repaglinide chitosan microsphere crosslinked with genipin was prepared by emulsification-chemical crosslinking method, and chitosan is used as coating materials, genipin as a crosslinking agent, repaglinide as active agent, span-80 as emulsifier. The prepared microspheres were also characterized by SEM, IR and DSC. The encapsulation efficiency of repaglinide microsphere was 4.4% and the drug loading was 21.9%.

Abstract: The determination of aldehyde in genipin(GP) was carried out through solution silver mirror reaction and curpous oxide reaction. Influence of various dosage, pH, temperature and reaction time on shrinkage temperature of GP-crosslinked porcine acellular dermal matrix (GP-pADM) were investigated. The cytotoxicity and cell morphology of GP-pADM were observed. The results reveal that the existence of aldehyde is proved by silver mirror reaction and curpous oxide reaction. With increasing dosage of GP, shrinkage temperature of pADM increase. And with increasing pH, temperature and time, shrinkage temperature exhibit an early ascending trend and then decline slightly. Cytotoxicity of GP-pADM is 0 grade with great morphology, cell L929 could adhesive grow on the surface and in the pore of this material. The implications of all this are that GP is an ideal biological crosslinking agent for biomaterials.

Abstract: Silk sericin, a gumming protein from silk cocoons, has been a considerable natural protein-based biopolymer for fabrication of desired constructs for potential tissue engineering applications. This study investigated the formulation of a novel biopolymeric silk sericin/poly (vinyl alcohol) film with genipin as crosslinking agent and its physical properties. Silk sericin itself forms a fragile material, adding other polymers such as poly (vinyl alcohol) and glycerin, a plasticizer, resulting in a strong and flexible matrix. The results indicated that at higher concentration of genipin (0.1% w/v), the percentages of crosslinking in sericin/poly (vinyl alcohol) films was significantly higher. The matrices also exhibited higher tensile modulus value and higher elasticity at higher genipin concentration which can be inferred to higher integrity of the structure compared to matrices with genipin at low concentration (0.01% w/v). On the other hand, the reverse patterns were found in percentages of light transmission and the releasing profile of sericin from the composite films. Adding genipin into the matrices resulted in a lower percentage of light transmission indicated the increase in opacity. The releasing profile of sericin from the films showed that high genipin concentrations reduced the peak of protein released and trended to provide the sustain-released profile of protein. These findings indicated that silk sericin film can be formed and the concentrations of crosslinking agents really affect its physical properties.