Rong Yang

Excessive inflammation caused by bacterial infection is the primary cause of implant failure. Antibiotic treatment often fails to prevent peri-implant infection and may induce unexpected drug resistance. Herein, a non-antibiotic strategy based on the synergy of silver ion release and macrophage reprogramming is proposed for preventing infection and bacteria-induced inflammation suppression by the organic-inorganic hybridization of silver nanoparticle (AgNP) and quercetin (Que) into a polydopamine (PDA)-based coating on the 3D framework of porous titanium (SQPdFT). Once the planktonic bacteria (e.g., Escherichia coli, Staphylococcus aureus) reach the surface of SQPdFT, released Que disrupts the bacterial membrane. Then, AgNP can penetrate the invading bacterium and kill them, which further inhibits the biofilm formation. Simultaneously, released Que can regulate macrophage polarization homeostasis via the peroxisome proliferators-activated receptors gamma (PPARγ)-mediated nuclear factor kappa-B (NF-κB) pathway, thereby terminating excessive inflammatory responses. These advantages facilitate the adhesion and osteogenic differentiation of bone marrow-derived mesenchymal stem cells (BMSCs), concomitantly suppressing osteoclast maturation, and eventually conferring superior mechanical stability to SQPdFT within the medullary cavity. In summary, owing to its excellent antibacterial effect, immune remodeling function, and pro-osteointegration ability, SQPdFT is a promising protective coating for titanium-based implants used in orthopedic replacement surgery.

The increasing demands in augmented somatosensory have promoted quantitative sensing to be an emerging need for athletic training/performance evaluation and physical rehabilitation. Neurons for the somatosensory system in the human body can capture the information of movements in time but only qualitatively. This work presents an electronic Exo-neuron (EEN) that can spread throughout the limbs for realizing augmented somatosensory by recording both muscular activity and joint motion quantitatively without site constraints or drift instability, even in strenuous activities. Simply based on low-cost liquid metal and clinically used adhesive elastomer, the EEN could be easily fabricated in large areas for limbs. It is thin (~120 μm), soft, stretchable (>500%), and conformal and further shows wide applications in sports, rehabilitation, health care, and entertainment.

The recent progress of MXene-based nanozymes is reviewed, including the synthetic methods, enzyme-like properties, and biomedical applications.

The past four years have witnessed booming progress in single-atom nanozymes (SANs), one of the newest generations of nanozymes with atomically dispersed metal sites for catalytic biomedical uses. They show distinct advantages over their nanoparticle-based counterparts, such as well-defined electronic/geometric structures and complete atomic utilization efficiency, thus offering opportunities to develop advanced nanozymes for practical uses. The atomically dispersed active centers in SANs could also facilitate the precise regulation of catalytic performance, while probing structure–activity relationship for in-depth understanding of mechanism. In this review, we first introduce the synthetic approaches, surface engineering, and characterization techniques of SANs. Subsequently, we discuss the enzyme-like properties of SANs, including some strategies for boosting their catalytic activities. Furthermore, we present their biomedical applications, ranging from biosensors, antibacterial uses, antioxidants, to therapeutics. Finally, the challenges and opportunities of SANs are prospected.