ABSTRACT
A novel, simple, and rapid method to fabricate thermoresponsive micropatterned substrate for cell adhesion, growth, and thermally induced detachment was developed. Thermoresponsive polymer, poly(N-isopropylacrylamide) (PNIPAAm), was grafted onto the surface of polystyrene (PS) film with microstructure by plasma-induced graft polymerization technique. The thermoresponsive micropatterned films were characterized by attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, hydrogen nuclear magnetic resonance ((1) H NMR) spectroscopy, X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM). These results indicated that the grafting ratio of PNIPAAm increased with increasing roughness of PS film. However, the microstructures on the substrate were not affected by grafted PNIPAAm. The optimal grafting conditions, such as plasma treatment time, monomer concentration, graft polymerization time, and graft medium were investigated. The thermoresponsive micropatterned films were investigated with the fibroblast cell (L929) adhesion, proliferation, and thermally induced detachment assay. The microstructure on the thermoresponsive micropatterned substrate facilitated cell adhesion above the lower critical solution temperature (LCST) of PNIPAAm and cell detachment below the LCST. Moreover, it can be used to regulate cell organization and tissue growth.
Subject(s)
Cell Culture Techniques/methods , Fibroblasts/cytology , Polystyrenes/chemistry , Temperature , Acrylamides/pharmacology , Acrylic Resins , Animals , Cell Adhesion , Cell Line , Cell Proliferation/drug effects , Fibroblasts/drug effects , Fibroblasts/ultrastructure , Membranes, Artificial , Mice , Microscopy, Electron, Scanning , Nitrogen/analysis , Photoelectron Spectroscopy , Plasma Gases/chemistry , Polymerization/drug effects , Polymers/pharmacology , Polystyrenes/pharmacology , Reproducibility of ResultsABSTRACT
A novel bio-functionalized thermoresponsive surface was prepared by UV-induced copolymerization of N-isopropylacrylamide (NIPAAm) and acrylic acid (AAc) and grafting onto tissue culture polystyrene (TCPS) dishes, followed by immobilization of galactose ligands. The results indicated that the roughness of surfaces was increased after copolymerization with NIPAAm and immobilization of galactose ligands. The amount of monomers grafted on TCPS was increased with increasing photografting time. The temperature sensitivity of surface was improved with increasing amount of NIPAAm grafted on TCPS, and surface hydrophilicity was enhanced by the introduction of carboxyl groups and galactose ligands, which accelerated cell detachment. Adhesion, proliferation, detachment and transshipment of human hepatoma cell line (HepG2) on the modified surfaces were examined. The immobilization of galactose ligands facilitated the cell adhesion and proliferation. HepG2 cells growing on the modified surfaces could be recovered spontaneously by only reducing culture temperature. The activity of cells obtained by temperature induction was higher than that obtained by enzymatic digestion.
Subject(s)
Galactose/chemistry , Acrylamides/chemistry , Acrylates/chemistry , Cell Adhesion , Cells, Cultured , Hep G2 Cells , Humans , Ligands , Microscopy, Atomic Force , Surface Properties , TemperatureABSTRACT
OBJECTIVE: To evaluate the efficacy of semiconductor low level laser irradiation for the treatment of postoperative exposure of hydroxyapatite orbital implants. METHODS: 22 cases with postoperative exposure of hydroxyapatite orbital implants were divided into three groups according to the size of implants exposure. The exposure wound in the 3 groups was irradated with semiconductor low level laser 5 min per day for 5-15 days. The follow-up period ranged from 2 to 24 months. RESULTS: In the group with less then 3 mm of exposure, the wound healed in 1 week after 5-10 days irradiation; in the group with implant exposure of 4-7 mm, the would healed in 1-2 weeks after 10-15 days irradiation; in the group with implant exposure of 8-10 mm, the would healed in 2-3 weeks after 10-15 days irradiation. Compared with the treatments of drugs and/or surgical repair, which was used for another 20 cases of exposure of hydroxyapatite orbital implants, semiconductor low level laser increased healing rate obviously in the groups with implant exposure of 4-7 mm and 8-10 mm (P = 0.019, 0.018). CONCLUSION: Semiconductor low level laser has better effects than drugs and/or surgical repair for exposure of hydroxyapatite orbital implants.
