Covalent Grafting of 5-Aminolevulinic Acid onto Polylactic Acid Films and Their Photodynamic Potency in Preserving Salmon.

A novel photodynamic inactivation (PDI)-mediated antimicrobial film of polylactic acid/5-aminolevulinic acid (PLA/ALA) was successfully fabricated by a covalent grafting method using low-temperature plasma. The chemical structure, surface morphology, hydrophilic ability, and mechanical and barrier properties of the films were characterized, and their antibacterial, anti-biofilm potency and preservation effects on ready-to-eat salmon were investigated during storage. Results showed that the amino group of ALA was covalently grafted with the carboxyl group on the surface of PLA after the plasma treatment, with the highest grafting rate reaching ∼50%. The fabricated PLA/ALA films displayed an enhanced barrier ability against water vapor and oxygen. Under blue light-emitting diode illumination, the PLA/ALA films generated massive reactive oxygen species from the endogenous porphyrins in cells induced by ALA and then fatally destroyed the cell wall of planktonic cells and the architectural structures of sessile biofilms of the pathogens (Listeria monocytogenes and Vibrio parahaemolyticus) and spoilage bacterium (Shewanella putrefaciens). More importantly, the PDI-mediated PLA/ALA films potently inhibited 99.9% native bacteria on ready-to-eat salmon and significantly suppressed the changes of its drip loss, pH, and lipid oxidation (MDA) during storage, and on this basis, the shelf life of salmon was extended by 4 days compared with that of the commercial polyethylene film. Therefore, the PDI-mediated PLA/ALA films are valid in inactivating harmful bacterial and preserving the quality of seafood.

[Effect of PRX-2 gene transferred by lipofectamine on the proliferation of human skin fibroblasts].

OBJECTIVE: To explore the effects of PRX-2 gene transferred by lipofectamine on the human skin fibroblasts. METHODS: Normal human skin fibroblasts were cultured and PRX-2 gene was transferred by lipofectamine. The proliferation of fibroblasts was detected by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) and flow cytometry. RESULTS: The proliferation of PRX-2-transfected fibroblasts was stronger than that of normal counterparts. There were fewer cells during G0-G1 period and more cells during S and G2-M periods. The proliferative index increased. CONCLUSION: The proliferation of fibroblasts may be modified by transfected PRX-2. Thus PRX-2 plays an important role during the healing of human skin wound.

[Auricular reconstruction with Medpor framework and temporal-parietal fascia flap].

OBJECTIVE: In search of a simpler and safer technique for auricular reconstruction with good appearance. METHODS: Medpor implant was used as auricular framework, and covered by temporal fascia flap and skin graft. RESULTS: Ear reconstruction was successfully achieved in 19 cases, the newly formed ears all had good appearance after edema disappeared 1 or 2 months postoperatively. CONCLUSION: Medpor is a kind of good implant material because it is steady in nature, easy to be sculptured. Temporal fascia flap is rich in blood supply, tough and tensile in biomechanics. So the combination of Medpor implant framework with temporal fascia flap is preferable in auricular reconstruction.

[One-stage reconstruction of postburn whole auricle defect with MEDPOR ear scaffold covered with superficial temporoparietal fascia flap].

OBJECTIVE: To study the effect and the key points in the operative procedure of the one-stage reconstruction of postburn whole auricle defect with medpor car scaffold covered with superficial temporoparietal fascia (TPF) flap. METHODS: Medpor car scaffold was embedded under the superficial temporal (TFP) fascia. Razor-thin skin was grafted onto the surface of the fascia flap. RESULTS: Fifteen patients with postburn whole auricle defect were treated by one-stage reconstruction with Medpor ear scaffold during the last four years. It was successful in all the patients with satisfactory appearance of the reconstructed ears. CONCLUSION: Medpor possessed friendly biological compatibility. The reconstruction gave satisfactory results, and its advantages consisted of short operational time, easy manipulation, less injury to patients and good auricular contour.