Search

Regenerative therapies, including the transplantation of spinal cord progenitor cells (SCPCs) derived from induced pluripotent stem cells (iPSCs), are promising treatment strategies for spinal cord injuries. However, the risk of tumorigenicity from residual iPSCs advocates an unmet need for rapid SCPCs safety profiling. Herein, a rapid (≈3000 cells min‐1) electrical‐based microfluidic biophysical cytometer is reported to detect low‐abundance iPSCs from SCPCs at single‐cell resolution. Based on multifrequency impedance measurements (0.3 to 12 MHz), biophysical features including cell size, deformability, membrane, and nucleus dielectric properties are simultaneously quantified as a cell is hydrodynamically stretched at a cross junction under continuous flow. A supervised uniform manifold approximation and projection (UMAP) model is further developed for impedance‐based quantification of undifferentiated iPSCs with high sensitivity (≈1% spiked iPSCs) and shows good correlations with SCPCs differentiation outcomes using two iPSC lines. Cell membrane opacity (day 1) is also identified as a novel early intrinsic predictive biomarker that exhibits a strong correlation with SCPC differentiation efficiency (day 10). Overall, it is envisioned that this label‐free and optic‐free platform technology can be further developed as a versatile cost‐effective process analytical tool to monitor or assess stem cell quality and safety in regenerative medicine. [ABSTRACT FROM AUTHOR]

To enhance the efficacy of photothermal therapy (PTT) at tumor sites, we designed a reactive oxygen species (ROS)-responsive gold nanoparticle (AuNP)-based nanosystem in which azide-decorated AuNPs (N3@AuNPs) and diselenide-coated alkyne-decorated AuNPs (Se/Ak@AuNPs) were separately prepared for selective clicking into nanoclusters when exposed to ROS. Se/Ak@AuNPs were dual-functionalized with alkyne moieties and diselenide linkers embedded in a long chain of polyethylene glycol (PEG) to enable the alkyne moieties of Se/Ak@AuNPs to be inaccessible to the azide moieties of N3@AuNPs owing to steric hindrance. At tumor sites where the ROS level is elevated due to the increased metabolic activity, cellular receptor signaling, mitochondrial dysfunction, and oncogene activity, the diselenide linkers were cleaved, leading to the liberation of the long PEG chains tethered to AuNPs, and the alkyne moieties could be recognized by the surrounding azide moieties to generate a click reaction. The clicked AuNPs formed clustered nanoparticles with increased size. Upon 808 nm laser irradiation, these large clusters of AuNPs significantly enhanced the photothermal conversion efficiency compared with that of isolated AuNPs. In vitro studies revealed that the AuNP clusters exhibited a noticeably higher apoptosis rate than AuNPs. Therefore, ROS-responsive clicked AuNP clusters can be a potential tool for PTT enhancement in cancer treatment. [ABSTRACT FROM AUTHOR]

The neuroinflammatory response that is elicited after spinal cord injury contributes to both tissue damage and reparative processes. The complex and dynamic cellular and molecular changes within the spinal cord microenvironment result in a functional imbalance of immune cells and their modulatory factors. To facilitate wound healing and repair, it is necessary to manipulate the immunological pathways during neuroinflammation to achieve successful therapeutic interventions. In this review, recent advancements and fresh perspectives on the consequences of neuroinflammation after SCI and modulation of the inflammatory responses through the use of molecular‐, cellular‐, and biomaterial‐based therapies to promote tissue regeneration and functional recovery will be discussed. [ABSTRACT FROM AUTHOR]