Deterministic Single Cell Encapsulation in Asymmetric Microenvironments to Direct Cell Polarity

Abstract

Various signals in tissue microenvironments are often unevenly distributed around cells. Cellular responses to asymmetric cell‐matrix adhesion in a 3D space remain generally unclear and are to be studied at the single‐cell resolution. Here, the authors developed a droplet‐based microfluidic approach to manufacture a pure population of single cells in a microscale layer of compartmentalized 3D hydrogel matrices with a tunable spatial presentation of ligands at the subcellular level. Cells elongate with an asymmetric presentation of the integrin adhesion ligand Arg‐Gly‐Asp (RGD), while cells expand isotropically with a symmetric presentation of RGD. Membrane tension is higher on the side of single cells interacting with RGD than on the side without RGD. Finite element analysis shows that a non‐uniform isotropic cell volume expansion model is sufficient to recapitulate the experimental results. At a longer timescale, asymmetric ligand presentation commits mesenchymal stem cells to the osteogenic lineage. Cdc42 is an essential mediator of cell polarization and lineage specification in response to asymmetric cell‐matrix adhesion. This study highlights the utility of precisely controlling 3D ligand presentation around single cells to direct cell polarity for regenerative engineering and medicine.

Facile and Rapid Microcontact Printing of Additive-Free Polydimethylsiloxane for Biological Patterning Diversity

“…Microscale droplet (microdroplet typically in picoliters or nanoliters) has exhibited the great availability in biomedical research . It offers an independent microenvironment for isolating biosamples or reactions with very small volume and even single cell/molecule resolution to either conduct biosensing detection (e.g., immunoassay and molecular amplification assay) or explore a large number of biological events such as protein crystallization and cell behaviors (e.g., growth and secretion). , Microdroplet arrays provide an eminent platform for manipulating and monitoring in high throughput, being suitable for screening-based studies.…”

Development of a programmable magnetic agitation device to maintain colloidal suspension of cells during microfluidic syringe pump perfusion

“…Four experimental agitation conditions were evaluated: no agitation, manual agitation, low-rate continuous agitation (velocity of *14 mm/s), and high-rate continuous agitation (*42 mm/s). The manual agitation condition was applied by hand as previously described [6][7][8][9], and served as a positive control. Cell density of the dispensed solutions was determined via counting using a hemocytometer.…”

“…Tissue engineering is a multidisciplinary area of research applying principles of biomaterial design and medicine to generate tissues and organs that better replicate their original functions and structures [1][2][3][4][5]. One technique used in tissue regeneration is the microscale encapsulation of single cells in a hydrogel for precision niche modeling and delivery via the use of droplet-based microfluidic devices [6][7][8][9]. To encapsulate cells, a colloid must be prepared consisting of the living cells and the aqueous phase of the material the cells will be encapsulated within.…”

Voxelated bioprinting of modular double-network bio-ink droplets

“…2e). The combination of experiments and theory shows that the TZ/NB-PAM single-network hydrogels allow for prescribed stiffness from ~400 Pa to 22 kPa, sufficient for cell encapsulation and most biomedical applications [18][19][20] .…”