Fig. 4: Electrical stimulation derived from charged substrate restricts virtual memory T cell polarization and promotes T cell proliferation.

a Graphic illustration of the study design for evaluating T cell function. OT-I cells were stimulated with OVA peptides (2 μg/mL) for 2 days and IL-2 (10 U/mL) for 4 days. b T cells were induced activation and expansion, followed by 10 × single-cell RNA-sequencing (scRNA-seq). The t-SNE plot shows the single T cells cultured on NC and HC nanocomposite membranes of 5 distinct clusters, including proliferative potential T cells (Tpp), virtual memory T cells (Tvm), central memory T cells (Tcm), effector memory T cells (Tem) and effector T cells (Teff). c Proportions of the 5 different clusters of T cells cultured on the NC and HC nanocomposite membranes. d GSEA of genes expressed in Tpp and Tvm. ES, enrichment score; NES, normalized enrichment score. e Network depicting interaction weights/strength between various cell types. The edge width is proportional to the indicated strength of statistically significant detected interactions. f Volcano plot analysis of gene expression in Tpp and Tvm cells. Red, genes upregulated in Tpp cells. Blue, genes downregulated in Tpp cells. Statistical significance was assessed by the Wilcoxon Rank-Sum test. g Expression of proliferation-associated genes in single T cells cultured on NC and HC nanocomposite membranes. h Genes that were significantly upregulated in Tpp cells cultured on HC nanocomposite membranes, compared with Tpp cells cultured on NC nanocomposite membranes, were analyzed using the GO database. Statistical significance was assessed by a one-sided hypergeometric test. i GSEA of genes expressed in Tpp from the HC group and NC group. ES, enrichment score; NES, normalized enrichment score. j OT-I cells were isolated and cultured on the nanocomposite membranes. T cells were treated with OVA peptides for 2 days and IL2 for 4 days, and proliferation was determined by CFSE dilution assay. k Flow cytometric analysis of the expression of Ki-67 in OT-I cells cultured on the nanocomposite membranes with varying surface charges. OVA peptides (2 μg/mL) and IL-2 (10 U/mL) were used to stimulate T cell activation and ensuing proliferation (n = 4 biological replicates, mean ± sem, ****P < 0.0001, two-tailed unpaired Student’s t test). l Flow cytometric analysis of the expression of CD25 in OT-I cells cultured on the nanocomposite membranes with varying surface charges. OVA peptides (2 μg/mL) and IL-2 (10 U/mL) were used to stimulate T cell activation and ensuing proliferation (n = 4 biological replicates, mean ± sem, ****P < 0.0001, two-tailed unpaired Student’s t test). m Flow cytometric analysis of the expression of phospho-STAT5 in OT-I cells cultured on the nanocomposite membranes with varying surface charges. OVA peptides (2 μg/mL) and IL-2 (10 U/mL) were used to stimulate T cell activation and ensuing proliferation (n = 4 biological replicates, mean ± sem, ****P < 0.0001, two-tailed unpaired Student’s t test). Data are representative of two (k, l, m) independent experiments. Source data are provided as a Source Data file.