Efficient Modification on PLLA by Ozone Treatment for Biomedical Applications

Abstract

RGDS (Arg-Gly-Asp-Ser) is immobilized on poly(L-lactic acid) (PLLA) with ozone oxidation and the addition of an intermediate reactant, acryl succinimide (ASI) to promote the grafting efficiency. A DPPH (2,2-di(4-tert-octylphenyl)-1-picrylhydrazyl) assay has revealed that the peroxide concentration can be controlled by adjusting the ozone treatment time. The immobilization of ASI is verified by elemental analysis. The peptide concentrations are in the effective order, as shown by means of high performance liquid chromatography (HPLC), and the grafting efficiency is proven to be relatively high compared with the previous studies. The culture of rat osteosarcoma 17/2.8 (ROS), osteoblastic-like cells, demonstrates that the grafting of RGDS can enhance the attachment and osteogenesis of ROS cells on PLLA. With the addition of ASI, the cultured ROS cells express normal function in proliferation and mineralization. From in vivo experiments, ASI immobilized on the surface is shown to be biocompatible. These results lead to the conclusion that the ozone treatment with the intermediate reactant ASI is an efficient, biocompatible, and easily controllable procedure to modify PLLA. Furthermore, the immobilization of RGDS in significant amounts following the ozone oxidation could further promote the biocompatibility and the osteoinduction of PLLA.

Plasma surface functionalization of biodegradable electrospun scaffolds for tissue engineering applications

“…The choice of an appropriate surface modification not compromising the delicate structure of nanofibers is a challenging step. Ion-beam, X-ray, ozone oxidation and gamma radiation are able to introduce reactive chemical functionalities on polymer surfaces, however they often alter the mechanical stability and degrade the polymer, thus rapidly damaging nanofibers [16,74,[89][90][91]. A traditional method used to incorporate and enhance the density of functional groups on biomaterial surfaces is wet chemical treatment.…”

An investigation into surface modification of polyethylene films for hydrophilicity enhancement by catalytic ozonation

“…Many studies have been conducted on the ozone modification of polymer surfaces in the last decade 8, 10–19. However, most of these studies were conducted in gaseous phase, only a few explored ozonation of polymers in distilled water, as well as in aqueous solutions of iso‐propanol and ammonia 16–19. Nevertheless, the use of homogeneous catalysts for surface peroxide generation is an area barely touched.…”

Ozone Gas as a Benign Sterilization Treatment for PLGA Nanofiber Scaffolds

“…While there are no literature examples of PLGA modification through ozone treatment, poly-L-lactic acid (PLLA) has been functionalized with celladhesive species through the groups generated by ozone gas exposure. 34,35,55 In comparison, the lack of chemical modification observed in this study is most likely due to the different ozone treatment methods used rather than differences in the polymers. In this study, the PLGA nanofiber samples were exposed to pulses of ozone at a relatively low pressure, with each pulse lasting *40 min.…”

“…This contrasts with continuous ozone flow in PLLA treatment, either in a dried chamber 35 or bubbled through isopropyl alcohol in a mixture with oxygen. 34,55 Based on our results, pulsed ozone gas appears to be a milder method than continuous ozone flow in terms of polymer oxidation while still possessing the ability to kill microbial contaminants.…”