Injectable and biodegradable piezoelectric hydrogel for osteoarthritis treatment.

Osteoarthritis affects millions of people worldwide but current treatments using analgesics or anti-inflammatory drugs only alleviate symptoms of this disease. Here, we present an injectable, biodegradable piezoelectric hydrogel, made of short electrospun poly-L-lactic acid nanofibers embedded inside a collagen matrix, which can be injected into the joints and self-produce localized electrical cues under ultrasound activation to drive cartilage healing. In vitro, data shows that the piezoelectric hydrogel with ultrasound can enhance cell migration and induce stem cells to secrete TGF-β1, which promotes chondrogenesis.

Corrosion of Metals During Use in Arthroplasty.

Arthroplasty implants can undergo corrosion at the modular components, trunnion, and hinges, owing to implant material makeup, micromotion, and interaction with body fluid. In this review, various mechanisms of corrosion in arthroplasty were explored with suggestions on means of improvement. We identified 10 methods including pitting, crevice, mechanically assisted crevice corrosion, fretting, fretting initiated crevice corrosion, mechanically assisted taper corrosion, galvanic corrosion, stress/tension, fatigue corrosion, and inflammatory cell induced corrosion.