Nano-needle strontium-substituted apatite coating enhances osteoporotic osseointegration through promoting osteogenesis and inhibiting osteoclastogenesis

Implant loosening remains a major clinical challenge for osteoporotic patients.This is because osteoclastic bone resorption rate is higher than osteoblastic bone formation rate in the case of osteoporosis,which results in poor bone repair.Strontium(Sr)has been widely accepted as an anti-osteoporosis element.In this study,we fabricated a series of apatite and Sr-substituted apatite coatings via electrochemical deposition under different acidic conditions.The results showed that Ca and Sr exhibited different mineralization behaviors.The main mineralization products for Ca were CaHPO4⋅2H2O and Ca3(PO4)2 with the structure changed from porous to spherical as the pH values increased.The main mineralization products for Sr were SrHPO4 and Sr5(PO4)3OH with the structure changed from flake to needle as the pH values increased.The in vitro experiment demonstrated that coatings fabricated at high pH condition with the presence of Sr were favorable to MSCs adhesion,spreading,proliferation,and osteogenic differentiation.In addition,Sr-substituted apatite coatings could evidently inhibit osteoclast differentiation and fusion.Moreover,the in vivo study indicated that nano-needle like Sr-substituted apatite coating could suppress osteoclastic activity,improve new bone formation,and enhance bone-implant integration.This study provided a new theoretical guidance for implant coating design and the fabricated Sr-substituted coating might have potential applications for osteoporotic patients.

A novel snail-inspired bionic design of titanium with strontium-substituted hydroxyapatite coating for promoting osseointegration

As the population ages,more and more people are suffering from osteoarthritis(OA),resulting in an increasing requirement for joint implants.Surface modification to improve the topology and composition of the implants has been proved to be an effective way to improve the primary stability and long-term success rate of joint implants.In this work,a bionic micro/nano-structure accompanied with a strontium-substituted hydroxyapatite(SrHA)coating was fabricated on titanium(Ti)surface via electrochemical corrosion,ultrasonic treatment,and hydrothermal deposition methods.Thein vitro study demonstrated that the bionic structure and the bioactive apatite could synergistically increase the expressions of integrin-related gene(ITGα5β1)and osteoblastic genes(Col-I and OCN),and thus promote osteoblast growth.In addition,owing to the anti-bone resorption property of Sr^(2+),the coating could effectively inhibit osteoclast differentiation and proliferation.In a word,the prepared samples not only promoted osteogenesis but also inhibited osteoclastogenesis.The in vivo experiment via a rabbit model found that the bionic structured surface provided the pore for new bone ingrowth,which was beneficial to the mechanical interlocking between the implant and bone.Moreover,the bionic structure and bioactive SrHA coating had a synergistic effect on promoting bone formation,osseointegration,and bone-implant bonding strength.This study therefore presented a new strategy to fabricate bio-functionalized Ti-based implants for potential application in orthopedics field.

A Novel Method for Preparation of 2-Chloro Enesulfonamides

A novel method for the synthesis of 2-chloro enesulfonamides via the one-pot addition-elimination of N-chloro-N-fluorobenzenesulfonamides （CFBSA） to styrenes in the presence of Et3N is described. A total of 20 examples are presented to illustrate this concept including various of styrenes.

A Convenient Preparation of Fluorinating Reagent F-TEDA Bearing Bisphenylsulfonylimide Counterion and Its Fluorination to Oxindoles

The direct preparation of a kind of fluorinating reagent 1[F-TEDA-N(SO_(2)Ph)_(2)]was realized in high yield via the complexation of N-fluorobenzenesulfonimide(NFSI)with 1-(chloromethyl)-1,4-diazabicyclo[2.2.2]octan-1-ium N',N'-bis-(benzenesulfonylimide)salt.In its fluorination to oxindoles,the fluorinating products 6 were afforded in moderate to high yields.