Nanomaterials for light-mediated therapeutics in deep tissue.

Light-mediated therapeutics, including photodynamic therapy, photothermal therapy and light-triggered drug delivery, have been widely studied due to their high specificity and effective therapy. However, conventional light-mediated therapies usually depend on the activation of light-sensitive molecules with UV or visible light, which have poor penetration in biological tissues. Over the past decade, efforts have been made to engineer nanosystems that can generate luminescence through excitation with near-infrared (NIR) light, ultrasound or X-ray. Certain nanosystems can even carry out light-mediated therapy through chemiluminescence, eliminating the need for external activation. Compared to UV or visible light, these 4 excitation modes penetrate more deeply into biological tissues, triggering light-mediated therapy in deeper tissues. In this review, we systematically report the design and mechanisms of different luminescent nanosystems excited by the 4 excitation sources, methods to enhance the generated luminescence, and recent applications of such nanosystems in deep tissue light-mediated therapeutics.

Metal-Organic Frameworks (MOFs) and Their Composites as Emerging Biomaterials for Osteoarthritis Treatment.

Metal-Organic Frameworks (MOFs) have emerged as a novel component in biomaterial formulations over the past 5 years. The bioactivity of MOFs in bone or cartilage tissue is mediated through the sustained delivery of metal ions, bioactive ligands, or drug molecules that are loaded into the porous MOF structures. Alternatively, bioactivity may also originate from structure-specific properties. The latter includes the availability and accessibility of open metal coordination sites for the catalytic conversion of biomolecules into active agents. This narrative highlight aims to inspire strategies to utilize MOFs for treating osteoarthritis (OA), with a special focus on augmenting hydrogel-based biomaterials with MOFs. The added value of MOFs in these hydrogel formulations is discussed, and the biological efficacy is compared to approaches applying classical injectable biomaterials for OA treatment. Possible future directions and pitfalls of these novel MOF-hydrogel composites are emphasized to assist future transition of MOFs into clinical applications.