Implantation of hypoxia-stimulated mesenchymal stem cell-derived exosome encapsulated in an adhesive hydrogel induced pro-angiogenic spinal cord repair through transporting HIF-1α and upregulating vascular endothelial growth factor expression in recipient endothelial cells.

The optical properties such as index of refraction and optical absorption of many chromophore-containing polymers are sensitive to the physical and chemical environment to which the polymers are exposed. To demonstrate such applications, chemical sensors to detect trace explosives are presented. The sensors use polymers that contain chromophores whose molecular structure consists of an electron donor and an electron acceptor connected by a charge-transfer bridge of conjugated π-orbital electrons. The polymers used for the trace explosives sensor are not poled, and the chromophores are randomly oriented in the polymer host. Waveguide microring resonator and fiber Bragg grating structures were used in these sensors to enhance the detection sensitivity. Because chromophores undergo photodecomposition under intense ultraviolet radiation, chromophore-containing polymers can be patterned with ultraviolet light to create optical resonator structures in a single photobleaching step. The chemical sensor has shown part-per-billion level sensitivity and good specificity to the vapor, in air, of an explosive simulant 2,4-dinitrotoluene. † Part of the "Larry Dalton Festschrift".

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Spinal cord injury (SCI) has seriously affected the lives of patients and brought economic and medical burdens to society. Biopharmaceuticals, including transplanted cells, growth factors, enzyme drugs, and microRNA, present multidimensional therapeutic effects in tissue repair and regeneration, and thus are widely utilized for the treatment of SCI. Nevertheless, they still encounter great challenges. The turbulent microenvironment accompanied by various destructive components following SCI has led to poor stability, low local accumulation, and reduced therapeutic efficacy of biopharmaceuticals. To this end, biomaterial‐based defenders (BBDs) that are capable of resisting the destructive components have shown great promise in improving the survival of transplanted cells or retaining the activity of the protein and nucleic acid drugs for the treatment of SCI. In this review, various types of biopharmaceuticals applied in SCI and their limitations are introduced. The destructive components that threaten the activities of biopharmaceuticals in the rigorous microenvironment are then summarized. In particular, the current research progress about BBDs boosting the efficacy of biopharmaceuticals for the treatment of SCI is illustrated with specific examples. The existing challenges and future perspectives are also provided.