Poly(lactic acid) stereocomplex (sc-PLA) prevails over homo-poly(lactic acid)s in many aspects and showed great potential as biomaterials depending on its extraordinary biological, thermal, and mechanical properties. In the past few years, sc-PLA has gained tremendous attention as a new approach to the development of new types of functional biomaterials. This paper summarizes recent progress in the application of the concept of sc-PLA in the design and fabrication of stabilized nanoparticles and in situ gelling hydrogels for biomedical applications.

To develop hydrogels with high mechanical strength for cell encapsulation and three-dimensional culture is a critical challenge for cartilage tissue engineering. In this study, novel double network (DN) hydrogels were fabricated and phosphate buffer solution (PBS) was used as the solvent to facilitate cell encapsulation. The tough DN hydrogels were prepared through a two-step photopolymerization using neutral oligo(2,2-dimethyltrimethylene carbonate)–poly(ethylene glycol)–oligo(2,2-dimethyltrimethylene carbonate)–diacrylate (DPD–DA) chains for the first network and methacrylated hyaluronic acid (HA–GMA) chains for the second network. The fracture stress values of the optimized and cell-laden DN hydrogels were 8.38 ± 0.67 MPa and 6.28 ± 1.26 MPa, respectively, which showed comparable mechanical strength with natural articular cartilage tissue. The live/dead cell viability assay of cell-laden DN hydrogels demonstrated the tough DN hydrogels have comparable cytocompatibility with PEG hydrogels. After long-term culture, cartilage-specific extra cellular matrix accumulated in these DN hydrogels. The results indicated the potential of the novel DN hydrogels as cartilage tissue engineering scaffolds.

The synthesis and application of biomass-derived carbon in energy storage have drawn increasing research attention due to the ease of fabrication, cost-effectiveness, and sustainability of the meso/microporous carbon produced from various biological precursors, including plants, fruits, microorganisms, and animals. Compared to the artificial nanostructured carbons, such as fullerene, carbon nanotube and graphene, the biomass-derived carbons may obtain superior capacitance, rate performance and stability in supercapacitor applications ascribing to their intrinsic nanoporous and hierarchical structures. However, challenges remain in processing techniques to obtain biomass-derived carbons with high carbon yield, high energy density, and controllable graphitic microstructures, which may require a clear understanding over the chemical and elemental compositions, and the intrinsic microstructural characteristics of the biological precursors. Herein we present comprehensive analyses over the impacts of the chemical and elemental compositions of the precursors on the carbon yield of the biomass, as well as the mechanism of chemical activation on the nanoporous structure development of the biomass-derived carbons. The structure–property relationship and functional performance of various biomass-derived carbons for supercapacitor applications are also discussed in detail and compared. Finally, useful insights are also provided for the improvements of biomass-derived carbons in supercapacitor applications.

With the integration of bioelectronics and materials science, implantable self‐powered systems for electrical stimulation medical devices have emerged as an innovative therapeutic approach, garnering significant attention in medical research. These devices achieve self‐powering through integrated energy conversion modules, such as triboelectric nanogenerators (TENGs) and piezoelectric nanogenerators (PENGs), significantly enhancing the portability and long‐term efficacy of therapeutic equipment. This review delves into the design strategies and clinical applications of implantable self‐powered systems, encompassing the design and optimization of energy harvesting modules, the selection and fabrication of adaptable electrode materials, innovations in systematic design strategies, and the extensive utilization of implantable self‐powered systems in biological therapies, including the treatment of neurological disorders, tissue regeneration engineering, drug delivery, and tumor therapy. Through a comprehensive analysis of the latest research progress, technical challenges, and future directions in these areas, this paper aims to provide valuable insights and inspiration for further research and clinical applications of implantable self‐powered systems.

Various cues from the microenvironment in which cells live can regulate cellular functions. In addition to biochemical cues, increasing evidence has demonstrated that mechanical cues (namely, substrate/matrix stiffness in this review) presented by the cell microenvironment are also critically important in regulating cellular functions. However, most studies on stiffness-regulated cellular functions mainly focus on 2D conditions, which might not be able to recapitulate the 3D microenvironment encountered by the cells in vivo. In contrast to the observations in 2D microenvironments, studies have already shown that cells respond differently to mechanical cues under 3D microenvironments. In this review, the mechanisms of cellular mechanosensing and mechanotransduction are briefly presented, followed by the introduction of the most studied 2D/3D platforms. The effects of substrate/matrix stiffness on cellular functions, including cell migration, spreading, proliferation, phenotype, and differentiation, under different dimensionalities are summarized and discussed. Finally, the persisting questions and future outlook are also proposed.