Surface treatment of 3D printed porous Ti6Al4V implants by ultraviolet photofunctionalization for improved osseointegration

Three-dimensional(3D)-printed porous Ti6Al4V implants play an important role in the reconstruction of bone defects.However,its osseointegration capacity needs to be further improved,and related methods are inadequate,especially lacking customized surface treatment technology.Consequently,we aimed to design an omnidirectional radiator based on ultraviolet(UV)photofunctionalization for the surface treatment of 3D-printed porous Ti6Al4V implants,and studied its osseointegration promotion effects in vitro and in vivo,while elucidating related mechanisms.Following UV treatment,the porous Ti6Al4V scaffolds exhibited significantly improved hydrophilicity,cytocompatibility,and alkaline phosphatase activity,while preserving their original mechanical properties.The increased osteointegration strength was further proven using a rabbit condyle defect model in vivo,in which UV treatment exhibited a high efficiency in the osteointegration enhancement of porous Ti6Al4V scaffolds by increasing bone ingrowth(BI),the bone-implant contact ratio(BICR),and the mineralized/osteoid bone ratio.The advantages of UV treatment for 3D-printed porous Ti6Al4V implants using the omnidirectional radiator in the study were as follows:1)it can significantly improve the osseointegration capacity of porous titanium implants despite the blocking out of UV rays by the porous structure;2)it can evenly treat the surface of porous implants while preserving their original topography or other morphological features;and 3)it is an easy-to-operate low-cost process,making it worthy of wide clinical application.

Effect of ultraviolet photofunctionalization of dental titanium implants on osseointegration

Objective： The aim of the current study was to evaluate the effect of ultraviolet（UV） photofunctionalization of dental titanium implants with exposure to the oral cavity on osseointegration in an animal model. Methods： Forty-eight titanium implants（Camlog~？ Conelog~？ 4.3 mmx9.0 mm） were placed epicrestally into the edentulous jaws of three minipigs and implant stability was assessed by measuring the implant stability quotient（ISQ）. Prior to implantation half of the implants were photofunctionalized with intense UV-light. After three months, the implants were exposed and ISQ was measured again. After six months of implant exposure, the minipigs were sacrificed and the harvested specimens were analyzed using histomorphometric, light, and fluorescence microscopy. Main results： Forty-two of 48 implants osseointegrated. The overall mean bone-implant contact area（BIC） was（64±22）%. No significant differences were found in BIC or ISQ value（multivariate analysis of variance（MANOVA）, P〉0.05） between implants with and without exposure to UV photofunctionalization. Conclusions： No significant effects were observed on osseointegration of dental titanium implants nine months after exposure of UV photofunctionalization.

MOLECULAR DESIGN OF FUNCTIONAL POLYMERS BASED ON UNIQUE PROPERTIES OF POLYMER CHAINS

The inclusion complex formation of α-CD, β-CD, and γ-CD with various water-soluble polymers has beeninvestigated, and the relationship between the chain cross-sectional areas of the polymers and the diameters of the cavities ofcyclodextrins (molecular recognition) was found. Polyrotaxanes and tubular polymers were prepared on the basis ofmolecular recognition. Several kinds of polymers having tetraphenylporphyrin (TPP) and paramagnetic metallotetraphenyl-porphyrin (AgTPP, CuTPP, VOTPP or ZnTPP) have been prepared by radical polymerization of the correspondingmonomers. Visible spectra of these polymers show hypochromism in the Sorer bands of TPP moieties as compared withthose of monomers. Polymer effects were observed in the magnetic behavior and oxygen adsorption of paramagneticmetallotetraphenylporphyrin moieties. Moreover, polymer effects on photophysical and photochemical behavior were foundin the amphiphilic polymers covalently tethered with small amounts of zinc(Ⅱ)-tetraphenylporphyrin (ZnTPP).