Soft Synthetic Cells with Mobile Membrane Ligands for Ex Vivo Expansion of Therapy-Relevant T Cell Phenotypes.

The expansion of T cells ex vivo is crucial for effective immunotherapy but currently limited by a lack of expansion approaches that closely mimic in vivo T cell activation. Taking inspiration from bottom-up synthetic biology, a new synthetic cell technology is introduced based on dispersed liquid-liquid phase-separated droplet-supported lipid bilayers (dsLBs) with tunable biochemical and biophysical characteristics, as artificial antigen presenting cells (aAPCs) for ex vivo T cell expansion. These findings obtained with the dsLB technology reveal three key insights: first, introducing laterally mobile stimulatory ligands on soft aAPCs promotes expansion of IL-4/IL-10 secreting regulatory CD8+ T cells, with a PD-1 negative phenotype, less prone to immune suppression. Second, it is demonstrated that lateral ligand mobility can mask differential T cell activation observed on substrates of varying stiffness. Third, dsLBs are applied to reveal a mechanosensitive component in bispecific Her2/CD3 T cell engager-mediated T cell activation. Based on these three insights, lateral ligand mobility, alongside receptor- and mechanosignaling, is proposed to be considered as a third crucial dimension for the design of ex vivo T cell expansion technologies.

Functional Integration of Synthetic Cells into 3D Microfluidic Devices for Artificial Organ-on-Chip Technologies.

Microfluidics play a pivotal role in organ-on-chip technologies and in the study of synthetic cells, especially in the development and analysis of artificial cell models. However, approaches that use synthetic cells as integral functional components for microfluidic systems to shape the microenvironment of natural living cells cultured on-chip have not been explored. Here, we integrate colloidosome-based synthetic cells into 3D microfluidic devices, pioneering the concept of synthetic cell-based microenvironments for organs-on-chip. We devise methods to create dense and stable networks of silica colloidosomes, enveloped by supported lipid bilayers, within microfluidic channels. These networks promote receptor-ligand interactions with on-chip cultured cells. Furthermore, we introduce a technique for the controlled release of growth factors from the synthetic cells into the channels, using a calcium alginate-based hydrogel formation within the colloidosomes. To demonstrate the potential of the technology, we present a modular plug-and-play lymph-node-on-a-chip prototype that guides the expansion of primary human T cells by stimulating receptor ligands on the T cells and modulating their cytokine environment. This integration of synthetic cells into microfluidic systems offers a new direction for organ-on-chip technologies and suggests further avenues for exploration in potential therapeutic applications. This article is protected by copyright. All rights reserved.