Hyaluronic acid-British anti-Lewisite as a safer chelation therapy for the treatment of arthroplasty-related metallosis.

Cobalt-containing alloys are useful for orthopedic applications due to their low volumetric wear rates, corrosion resistance, high mechanical strength, hardness, and fatigue resistance. Unfortunately, these prosthetics release significant levels of cobalt ions, which was only discovered after their widespread implantation into patients requiring hip replacements. These cobalt ions can result in local toxic effects-including peri-implant toxicity, aseptic loosening, and pseudotumor-as well as systemic toxic effects-including neurological, cardiovascular, and endocrine disorders. Failing metal-on-metal (MoM) implants usually necessitate painful, risky, and costly revision surgeries. To treat metallosis arising from failing MoM implants, a synovial fluid-mimicking chelator was designed to remove these metal ions. Hyaluronic acid (HA), the major chemical component of synovial fluid, was functionalized with British anti-Lewisite (BAL) to create a chelator (BAL-HA). BAL-HA effectively binds cobalt and rescues in vitro cell vitality (up to 370% of cells exposed to IC50 levels of cobalt) and enhances the rate of clearance of cobalt in vivo (t1/2 from 48 h to 6 h). A metallosis model was also created to investigate our therapy. Results demonstrate that BAL-HA chelator system is biocompatible and capable of capturing significant amounts of cobalt ions from the hip joint within 30 min, with no risk of kidney failure. This chelation therapy has the potential to mitigate cobalt toxicity from failing MoM implants through noninvasive injections into the joint.

Polyester functional graphenic materials as a mechanically enhanced scaffold for tissue regeneration.

Traditional metal implants such as titanium, cobalt, and chromium have found wide utility in medicine; however, these come with a risk of toxicity. To overcome metal-related toxicity and enable degradability, polyesters including polycaprolactone (PCL), polylactic acid (PLA), and polyglycolic acid (PGA) show promise for the replacement of various biomedical applications of metals due to their accepted biocompatibility and FDA approval. However, polyesters are less stiff than their metallic counterparts, limiting their application to non-load bearing injury sites, such as fixation hardware for fingers. To improve mechanical properties, graphene oxide (GO)-polyester composites are a promising class of biodegradable scaffolds. Initial reports of these composites are encouraging, but mechanical properties still fall short. Traditional composites rely on non-covalent association between GO and the polyesters, which often leads to failure at the interface and weakens the overall strength of the material. Herein, we present a strategy for attachment of these FDA-approved polyesters onto a derivative of GO using a robust covalent bond. By covalently functionalizing the graphenic backbone with polyesters and without metal catalysts, we create functional graphenic materials (FGMs) to not only simultaneously retain biodegradability and compatibility, but also mechanically strengthen PCL, PLA, and PGA; we observed an average increase in the Young's modulus of over 140% compared to the graphenic backbone. These polyester-functionalized FGMs are a promising platform technology for tissue implants.