Synthetic antigen-presenting cells (APCs) are used to mediate scalable ex vivo T-cell expansion for adoptive cell therapy. Recently, we developed APC-mimetic scaffolds (APC-ms), which present signals to T cells in a physiological manner to mediate rapid and controlled T-cell expansion. APC-ms are composed of individual high-aspect-ratio silica microrods loaded with soluble mitogenic cues and coated with liposomes of defined compositions, to form supported lipid bilayers. Membrane-bound ligands for stimulation and co-stimulation of T-cell receptors are presented via the fluid, synthetic membranes, while mitogenic cues are released slowly from the microrods. In culture, interacting T cells assemble the individual APC-ms microrods into a biodegradable 3D matrix. Compared to conventional methods, APC-ms facilitates several-fold greater polyclonal T-cell expansion and improved antigen-specific enrichment of rare T-cell subpopulations. Here we provide a detailed protocol for APC-ms synthesis and use for human T-cell activation, and discuss important considerations for material design and T-cell co-culture. This protocol describes the facile assembly of APC-ms in ~4 h and rapid expansion or enrichment of relevant T-cell clones in <2 weeks, and is applicable for T-cell manufacturing and assay development.