T cell-based immunotherapy has shown immense therapeutic potential for the late-stage treatment of cancer. The synthetic ex vivo activation of T cells is a key step in manufacturing these therapies, inducing proliferation and cytotoxic functionalization of the cells before reinfusion into the patient. This is generally done with the use of artificial antigen presenting cells (aAPCs) consisting of antibodies triggering the receptor signaling necessary for activation directly conjugated to a spherical polystyrene bead. Although intended to mimic the function of antigen presenting cells (APCs) in the body, currently used aAPCs do not fully recapitulate natural size, morphology, or membrane fluidity, all of which have been demonstrated to be important determinants of activation properties. Therefore, there is a need for an activation platform that more closely mimics APCs in vivo, which could significantly improve the efficiency of T cell activation for use in cancer immunotherapies. To achieve this, we utilize cell-molded silica microparticles that retain the size and morphology of their cellular templates. The fusion of an antibody-loaded lipid bilayer to these silica microparticles results in a closer recreation of natural APCs. We have fabricated these cell-molded silica aAPCs with various cell template morphologies and lipid compositions. Using a variety of cell-based assays, we are characterizing the capacity of these aAPCs to induce T cell proliferation, cytokine release, and surface marker expression, all of which are metrics indicative of activation. If these results indicate that this platform successfully improves the efficiency of T cell activation as compared to current alternatives, this has the potential to improve the cost and scalability of these promising cancer treatments.