Multifunctional modifications of polyetheretherketone implants for bone repair: A comprehensive review.

Polyetheretherketone (PEEK) has emerged as a highly promising orthopedic implantation material due to its elastic modulus which is comparable to that of natural bone. This polymer exhibits impressive properties for bone implantation such as corrosion resistance, fatigue resistance, self-lubrication and chemical stability. Significantly, compared to metal-based implants, PEEK implants have mechanical properties that are closer to natural bone, which can mitigate the "stress shielding" effect in bone implantation. Nevertheless, PEEK is incapable of inducing osteogenesis due to its bio-inert molecular structure, thereby hindering the osseointegration process. To optimize the clinical application of PEEK, researchers have been working on promoting its bioactivity and endowing this polymer with beneficial properties, such as antibacterial, anti-inflammatory, anti-tumor, and angiogenesis-promoting capabilities. Considering the significant growth of research on PEEK implants over the past 5 years, this review aims to present a timely update on PEEK's modification methods. By highlighting the latest advancements in PEEK modification, we hope to provide guidance and inspiration for researchers in developing the next generation bone implants and optimizing their clinical applications.

Targeting hepatitis B virus cccDNA levels: Recent progress in seeking small molecule drug candidates.

Hepatitis B virus (HBV) infection is a major global health problem that puts people at high risk of death from cirrhosis and liver cancer. The presence of covalently closed circular DNA (cccDNA) in infected cells is considered to be the main obstacle to curing chronic hepatitis B. At present, the cccDNA cannot be completely eliminated by standard treatments. There is an urgent need to develop drugs or therapies that can reduce HBV cccDNA levels in infected cells. We summarize the discovery and optimization of small molecules that target cccDNA synthesis and degradation. These compounds are cccDNA synthesis inhibitors, cccDNA reducers, core protein allosteric modulators, ribonuclease H inhibitors, cccDNA transcriptional modulators, HBx inhibitors and other small molecules that reduce cccDNA levels.