Control of biomechanical properties by cell encapsulation*

Encapsulation of single cells is a powerful technique which has been used in various fields such as biotechnology, regenerative medicine, and drug delivery. Single cell encapsulation can be used to protect immune cells by providing cytocompatible coatings to strengthen cells against mechanical and environmental stresses. Silk fibroin, derived from the silkworm Bombyx mori is a promising biomaterial for encapsulation due to its biocompatibility and capacity to maintain cell functionality. In this work, THP-1 cells, a human leukemia monocytic cell line, were encapsulated with chemically modified charged silks, ionomers, through electrostatic layer-by-layer deposition. We will present findings on cell viability and functionality, as well as the cytocompatibility of the silk material in these systems. We measured elasticity maps and cellular stiffness using the atomic force microscope (AFM). Additionally, by applying consistent sheer stress to cells both pre and post-encapsulation, we observed that both stiffness and cytoprotection of the cells increased after the silk encapsulation. Such encapsulation offers unique opportunities to fine-tune the cellular assembly and biomechanics, while also promoting compatible systems that protect cells both during the biomaterial deposition process as well as in the subsequent applications of these coated cells. This work provides significant insights into the design of novel biomaterial interfaces for cellular protection and functionalization.