Particle separation and sorting techniques based on microfluidics have found extensive applications and are increasingly gaining prominence. This research presents the design and fabrication of a microfluidic device for separating cells using deterministic lateral displacement (DLD), enabling accuracy and continuity while being size-based. Nevertheless, it remains demanding, to completely reverse the detrimental effects of the boundaries that disturb the fluidic flow in the channel and reduce particle separation efficiency. This study introduces a novel approach to enhance the boundary structure of channels. By using this design, separation efficiency is boosted, and the fluid behavior around the walls is improved. The boundary correction (BC) enhances the operation of the microchannel and is very effective in microchannels. With boundary correction, the device exhibited improved separation efficiencies, but in its absence, separation efficiencies dropped. The collected microscopic images of the isolation of prostate cancer cell lines and red blood cells revealed promising outcomes. The efficiency of circulating tumor cell (CTC) throughput in the microfluidic channel, quantified as the ratio or proportion of tumor cells exiting the channel to cells entering it, exceeds 93%. Moreover, the efficiency of CTC isolation, expressed as the proportion of tumor cells from the upper outlet of the microfluidic channel to all cells, is over 89%. Additionally, the efficiency of red blood cell isolation, evaluated as the ratio of red blood cells from the lower outlet of the microfluidic channel to all cells, surpasses 77%. While using the same DLD separator without boundary correction reduced the separation efficiency by around 5%.

Background: Devices that mimic the functions of human skin are known as “electronic skin,” and they must have characteristics like high sensitivity, a wide dynamic range, high spatial homogeneity, cheap cost, wide area easy processing, and the ability to distinguish between diverse external inputs. Methods: This study introduces a novel approach, termed microfluidic droplet-based emulsion self-assembly (DMESA), for fabricating 3D microstructured elastomer layers using polydimethylsiloxane (PDMS). The method aims to produce accurate capacitive pressure sensors suitable for electronic skin (e-skin) applications. The DMESA method facilitates the creation of uniform-sized spherical micropores dispersed across a significant area without requiring a template, ensuring excellent spatial homogeneity. Results: Micropore size adjustment, ranging from 100 to 600 μm, allows for customization of pressure sensor sensitivity. The active layer of the capacitive pressure sensor is formed by the three-dimensional elastomer itself. Experimental results demonstrate the outstanding performance of the DMESA approach. It offers simplicity in processing, the ability to adjust performance parameters, excellent spatial homogeneity, and the capability to differentiate varied inputs. Capacitive pressure sensors fabricated using this method exhibit high sensitivity and dynamic amplitude, making them promising candidates for various e-skin applications. Conclusion: The DMESA method presents a highly promising solution for fabricating 3D microstructured elastomer layers for capacitive pressure sensors in e-skin technology. Its simplicity, performance adjustability, spatial homogeneity, and sensitivity to different inputs make it suitable for a wide range of electronic skin applications.

By shaping biochemical gradients and extracellular matrix cues within the local microenvironment, cellular spatial organization plays a critical role in regulating tissue development, homeostasis, and disease progression. Microfluidic platforms are highly suitable for the study of these cell-cell and cell-matrix interactions as they precisely control cell arrangement and gradients compared to conventional experimental systems. Cells are often embedded within hydrogels to improve physiological relevance by enabling matrix-mediated signaling. However, many designs restrict the number and arrangement of hydrogels or generate gradients in only one dimension, limiting their ability to recapitulate complex tissue architectures. To address this need, we introduce a 3D printed microfluidic insert compatible with microplates that allows patterning of up to ten unique hydrogel arrays in two dimensions and generation of parallel or orthogonal concentration gradients. We first develop a physics-based computational model of hydrogel filling to define design parameters that ensure robust hydrogel patterning. We then establish perpendicular concentration gradients on timescales relevant to biological experiments. Furthermore, we demonstrate high cell viability in our 3D-printed devices and control of fibroblast migration across multiple patterned hydrogels. Finally, we monitor the recruitment of primary human monocyte towards cell-free and fibroblast-seeded 3D collagen matrices. Our microfluidic insert platform is compatible with high-throughput automation workflows and allows for interrogation of spatially variant signals that regulate cell migration and cell-cell signaling in physiologically-relevant 3D microenvironments.