Ming-Wei Lee

Photocrosslinkable gellan gum film as an anti-adhesion barrier.

The purpose of this study was to develop a gellan gum-based film which could be photocrosslinked for medical applications. Gellan gum was grafted with cinnamate to yield the photo crosslinkable polymer (gellan gum-cin). This material had 14.7% of its D-galacturonic residues reacted with cinnamate groups and displayed maximum absorption at 254 nm. Investigation of the photochemical properties showed that the crosslinking efficiency was 82% after 16 min of UV irradiation. The anti-adhesion films prepared from gellan gum-cin polymers exhibited high gel contents (88 ± 2%) and suitable mechanical properties. When implanted into rats, the gellan gum-cin film exhibited the most promising anti-adhesion potential in 2 out of 10 rats without forming any tissue adhesion. Furthermore, the gellan gum-cin film could effectively inhibit inflammation in rats based on the results of fluid leukocyte analyses. The gellan gum-cin film thus has potential in clinical applications.

Polygalacturonic acid hydrogel with short-chain hyaluronate cross-linker to prevent postoperative adhesion

The purpose of this study was to develop a poly(galacturonic acid) (PGA)-based hydrogel using a short-chain hyaluronate (sHA) cross-linker for medical applications. PGA was grafted with adipic acid dihydrazide (ADH) to yield PGA–ADH, an amine-containing PGA derivative. This PGA–ADH formed a water-insoluble hydrogel by reacting with 1,1′-carbonyldiimidazole (CDI)–grafted sHA (sHA–CDI) in aqueous solution. The sHA–cross-linked PGA hydrogel has a water content of about 94%–97% and compressive modulus of 10.7–26.9 kPa. The in vitro data indicated that the sHA–cross-linked PGA hydrogel is degradable and noncytotoxic, thus suitable for biomedical applications. Animal implant studies showed that the sHA–cross-linked PGA hydrogel membrane exhibited antiadhesion potency, significantly higher than that found in untreated rats and has great potential for future clinical applications.

Physical and biological effects of gellan gum on decreasing postoperative adhesion in a rat model

An antiadhesion membrane made from gellan gum was fabricated and characterized. A 12-µm-thick membrane of gellan gum was prepared and reacted with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide to obtain a cross-linked membrane (G/A70) with 87% gel content and a tensile strength of 46.5 MPa. In vivo, the G/A70 membrane had 90% less tissue adhesion. Inflammation-related and extracellular matrix protein gene expression in a rat model of abdominal surgery was found by real-time quantitative reverse transcription polymerase chain reaction analysis. On day 3, after surgery, the gene expression of ceruloplasmin and type V collagen in the G/A70-treated group was 1.9 and 0.3 times that of the control group, respectively. The G/A70 membrane elicited mild inflammation but suppressed type V collagen synthesis and reduced the occurrence of tissue adhesion. These findings provide insights into the properties of gellan gum antiadhesion membranes and help to overcome problems involving tissue adhesions in surgical procedures.

Preparation and characterization of gellan gum/glucosamine/clioquinol film as oral cancer treatment patch

To administer cancer drugs with improved convenience to patients and to enhance the bioavailability of cancer drugs for oral cancer therapy, this study prepared gellan gum/glucosamine/clioquinol (GG/GS/CQ) film as the oral cancer treatment patch. GG/GS/CQ film fabricated through the EDC-mediated coupling reactions (GG/GS/CQ/EDC film). The film of the physicochemical properties and drug release kinetics were studied. The effectiveness of GG/GS/CQ/EDC film as oral cancer treatment patch were evaluated with the animal model. The results confirmed that CQ can be incorporated via EDC-mediated covalent conjugation to gellan gum/glucosamine. Mechanical testing revealed that the maximum tensile strength and elongation percentage at break were 1.91kgf/mm2 and 5.01% for GG/GS/CQ/EDC film. After a drug release experiment lasting 45days, 86.8% of CQ was released from GG/GS/CQ/EDC film. The Huguchi model fit the GG/GS/CQ/EDC drug release data with high correlation coefficients (R2=0.9994, respectively). The effect of the CQ dose on oral cancer cells (OC-2) was tested, and the IC50 of CQ alone and CQ with 10μM CuCl2 were 9.59 and 2.22μM, respectively. The animal testing indicated that GG/GS/CQ/EDC film was decreased epidermal growth factor receptor (EGFR) expression and suppress tumor progression. These findings provide insights into a possible use for GG/GS/CQ/EDC film for oral ca in clinical practice. The GG/GS/CQ/EDC film is suitable as the dressing for use in the treatment of early-stage cancer or as wound care after surgery in late-stage of oral cancer treatment.

Preparation and evaluation of collagen I/ gellan Gum/β-TCP microspheres as bone graft substitute materials

Collagen I is the main component of protein in bone and exhibits many excellent applications in biomedical fields. Gellan gum possesses good biocompatible, biodegradable and good mechanical property, and shows great potentials as tissue engineering scaffold or cell culture substrate. Therefore, the aim of this study was to use collagen I, gellan gum and β-TCP to prepare collagen I/gellan gum/β-TCP microspheres by emulsion method as bone graft substitute materials. The preliminary results showed that collagen I/gellan gum/β-TCP microspheres had particle size distribution between 500-1000 μP in diameter and exhibited better mechanical strength. These microspheres also showed good biocompatibility in cell activity test.

Nitric oxide regualte mitochondrial activity and apoptosis through protein s-nitrosylation for preimplantation embryo development

Purpose Previous studies reported that patients with endometriosis had excess nitric oxide (NO) in the reproductive tract and poor embryo development in IVF cycles. This study aims to elucidate the effects of NO on early embryo development.