Axonal regeneration.

<p>NF200-positive axons were observed in the conduit+NT-3+NSCs (A) and conduit+NSCs (B) groups 8 weeks after implantation. (C) Histograms showing the number of NF200-positive axons for each group. Scale bar  =  20 µm, *<i>P</i><0.05; n = 7.</p

Conduit implantation after spinal cord transection facilitates tissue bridging and NSC survival.

<p>(A–B) Surgical procedure for implantation of conduits into completely transected rat spinal cords. (C) Gross appearance of spinal cords 8 weeks after implantation of the conduits. (D–E) Confocal fluorescent images of NSC survival in the conduit+NT-3+NSCs (D) and conduit+NSCs (E) groups 8 weeks after implantation. (F) Percentage of NSC survival for each group. Scale bar  =  100 µm; *<i>P</i><0.05; n = 7.</p

Differentiation profiles of NSCs in vivo.

<p>(A–F) Tissue samples were immunostained with MAP-2 for neurons (A, D), GFAP for astrocytes (B, E), and CNPase for oligodendrocytes (C, F) from the conduit+NT-3+NSCs (A–C) and conduit+NSCs groups (D–F). White arrows indicate the representative differentiated cells. (G) Quantification of NSC differentiation profile for each group. Scale bar  =  20 µm. *<i>P</i><0.05; n = 7.</p

Neurosphere and PCLA scaffold.

<p>(A) A neurosphere visualized under a light microscope. (B) GFP-positive neurosphere visualized under a fluorescent microscope. (C) SEM images of the inner wall of the PCLA conduit without NSCs. (D) NSCs adhered to the inner wall of the PCLA conduit. The black box show representative cells from the white box at higher magnification to enhance visualization of cellular morphology under SEM. Scale bars =  100 µm in A–B, 50 µm in C, and 10 µm in D.</p

BBB locomotor scores were evaluated weekly for 8 weeks after SCI.

<p>At 4 weeks and thereafter, the conduit+NT-3+NSCs group displayed significant behavioral improvement compared with the other two groups. *P<0.05; n = 6.</p

Cumulative release profile of bioactive NT-3 from NT-3-immobilized PCLA-SF conduits in vitro.

<p>n = 3.</p

In Situ Generation of Fluorescent Amino Acids and Peptides via Double C–H Activation/Annulation

Unnatural fluorescent amino acids have been synthesized to obtain better emission wavelengths, fluorescence lifetime, and quantum yields. Despite major advances, most of them face inherent restrictions as fluorophores and are limited to the methods from coupling between amino acids and fluorophores. Herein, we develop a Rh­(III)-catalyzed double C–H activation/annulation reaction of diverse benzamides with alkynes for the synthesis of tricyclic-fused aromatic hydrocarbon carbocations. The robustness of this strategy is demonstrated by the diversification of Lys-based amino acids and peptides, in situ generating tricyclic fluorophores. This method features broad substrate scope and high atom and step economy as well as high chemo- and site selectivity. Unsymmetrical double C–H activation/annulation employing two different alkynes is well tolerated to produce the unnatural fluorescent amino acids in high yields. These tricyclic fluorophores display tunable fluorescence emission, low cytotoxicity, and the potential for specifically targeting lysosomes

Synthesis and Characterization of Thermoresponsive Hydrogels Based on <i>N</i>‑Isopropylacrylamide Crosslinked with 4,4′-Dihydroxybiphenyl Diacrylate

A novel crosslinker [4,4′-dihydroxybiphenyl diacrylate (44BDA)] was developed, and a series of temperature-responsive hydrogels were synthesized through free radical polymerization of <i>N</i>-isopropylacrylamide (NIPAAm) with 44BDA. The temperature-responsive behavior of the resulting gels was characterized by swelling studies, and the lower critical solution temperature (LCST) of the hydrogels was characterized through differential scanning calorimetry. Increased content of 44BDA led to a decreased swelling ratio and shifted the LCST to lower temperatures. These novel hydrogels also displayed resiliency through multiple swelling–deswelling cycles, and their temperature responsiveness was reversible. The successful synthesis of NIPAAm-based hydrogels crosslinked with 44BDA has led to a new class of temperature-responsive hydrogel systems with a variety of potential applications

Fluorescent staining for cell viability of NSCs grown on PCLA (A), PCLA-SF (B), and PCLA-SF-NT-3 (C) membranes for 14 days.

<p>Living cells (white arrows) were in green and dead cells (white arrowheads) were in red. (D) The percentage of live cells. Scale bars = 100 µm; *<i>P</i><0.05; n = 4.</p

Oxidation-Induced Protein Cross-Linking in Mammalian Cells

A proximity-enabled protein cross-linking strategy with additional spatiotemporal control is highly desirable. Here, we report an oxidation-induced protein cross-linking strategy involving the incorporation of a vinyl thioether group into proteins in both Escherichia coli and mammalian cells via genetic code expansion. We demonstrated that vinyl thioether can be selectively induced by exogenously added oxidant or by reactive oxygen species from the cellular environment, as well as by photocatalysts, and converted into a Michael acceptor, enabling fluorescence labeling and protein cross-linking