Polyetheretherketone with citrate potentiated influx of copper boosts osteogenesis,angiogenesis,and bacteria-triggered antibacterial abilities

A well designed coating for polyetheretherketone(PEEK)implants can provide enough support to overcome crucial medical challenges,which are insufficient osseointegration and high rate of infection.Herein,we utilize the co-deposition of polydopamine(PDA)and copper-citrate nanoclusters to construct a p H-responsive coating on porous PEEK for synergistic bone regeneration,vascular formation and anti-infection.Specifically,this PDA coating released high dose of copper and citrate at lower p H value,which increased intracellular copper content,boosted production of reactive oxygen species and severe damage of protein,leading to killing of 93%planktonic bacterial and eradication of adherent bacteria.At p H of 7.4,the release of copper and citrate were in a slow and sustained behavior,synergistically enhanced vascular formation potential and osteodiffereration of Ad-MSC in vitro.After implanted in rabbit tibia for 6 and 12 weeks,the micro-CT evaluation and histological analysis consistently highlighted the ability of this PDA coating to increase new bone formation adjacent to coated PEEK implant and enhance bone-implant interfacial integration.These results were proven to be related to the synergistic effect that citrate facilitated a 2-fold influx of copper into cells,which not only enhanced the bacteria-killing ability but also encouraged bone regeneration of implants.This present work provides an effective method to control infections while promoting osseointegration simultaneously,which will show tremendous clinical application and can be a solution to current challenges facing orthopedics.

Positive/Negative Phototropism:Controllable Molecular Actuators with Different Bending Behavior

Herein,a series of molecular actuators based on the crystals of(E)-2-(4-fluorostyryl)benzo[d]oxazole(BOAF4),(E)-2-(2,4-difluorostyryl)benzo[d]oxazole(BOAF24),(E)-2-(4-fluorostyryl)benzo[d]thiazole(BTAF4),and(E)-2-(2,4-difluorostyryl)benzo[d]thiazole(BTAF24)showed unique bending behavior under UV irradiation.The one-dimensional(1D)crystals of BOAF4 and BTAF4 bent toward light,whereas those of BOAF24 and BTAF24 bent away from light.Although the chemical structures of these compounds are similar,the authors found that F···H–C interaction played a key role in the different molecular packing in structures crystals,which led to the positive/negative phototropism of the actuators.Moreover,theoretical calculations were carried out to reveal the mechanical properties of the crystals.Taking advantage of these photomechanical properties,the authors achieved the potential application in pushing objects,as well as enriching and removing pollutants.Hence,the molecular actuators with different bending behavior could be fabricated by introducing different number of F atom,which may open a novel gate for crystal engineering.