Synthesis of Cell-Adhesive Anisotropic Multifunctional Particles by Stop Flow Lithography and Streptavidin–Biotin Interactions

Abstract

Cell-adhesive particles are of significant interest in biotechnology, the bioengineering of complex tissues, and biomedical research. Their applications range from platforms to increase the efficiency of anchorage-dependent cell culture to building blocks to loading cells in heterogeneous structures to clonal-population growth monitoring to cell sorting. Although useful, currently available cell-adhesive particles can accommodate only homogeneous cell culture. Here, we report the design of anisotropic hydrogel microparticles with tunable cell-adhesive regions as first step toward micropatterned cell cultures on particles. We employed stop flow lithography (SFL), the coupling reaction between amine and N-hydroxysuccinimide (NHS) and streptavidin–biotin chemistry to adjust the localization of conjugated collagen and poly-L-lysine on the surface of microscale particles. Using the new particles, we demonstrate the attachment and formation of tight junctions between brain endothelial cells. We also demonstrate the geometric patterning of breast cancer cells on particles with heterogeneous collagen coatings. This new approach avoids the exposure of cells to potentially toxic photoinitiators and ultraviolet light and decouples in time the microparticle synthesis and the cell culture steps to take advantage of the most recent advances in cell patterning available for traditional culture substrates.

High‐Throughput Fabrication and Modular Assembly of 3D Heterogeneous Microscale Tissues

“…Furthermore, flow lithography can be divided into continuous flow lithography (CFL) and stop flow lithography (SFL) . CFL fabricated microstructures are under a continuous flow of the monomer, which limits its resolution.…”

Flow lithography in ultraviolet-curable polydimethylsiloxane microfluidic chips

“…Although SFL productivity relies on this total period of time, we focused on altering only the flow time in this study because the other parameters are independent of inlet pressure. 2 Considering that the flow time of 400-800 ms and the inlet pressure of 14-24 kPa have typically been used for SFL with thermally cured PDMS chips, 16,44,49 we tested a flow time (40 ms) an order of magnitude shorter in duration in combination with a pressure of 400 kPa (higher than the burst pressure for conventional PDMS chips) in the UV-cured PDMS chips. As expected, the application of 20 kPa for 40 ms in thermally cured PDMS chips obviously precluded photocrosslinked PEGDA microparticles from being flushed out of a region of UV exposure after 1 cycle (left top and bottom panels in Fig.…”

“…In brief, we were able to successfully increase the throughput [cycle/min] of SFL by a factor of at least 2.04 and of up to 3.64 by reducing the cycle time to 440 ms, compared with a typical cycle time range of 900-1600 ms. 16,44,49 We performed the SFL experiment with a cycle time of 900 ms with a conventional PDMS chip as a conservative control (Table I). …”

“…[1][2][3][4] Owing to this merit of FL, new applications have emerged for in vitro diagnostics, [5][6][7][8][9][10][11][12][13] selfassembly of microparticles, 14,15 tissue engineering, [16][17][18] and drug delivery. 19 Materials that enable microfluidic devices to perform FL must satisfy two major requirements.…”

Flexible Octopus‐Shaped Hydrogel Particles for Specific Cell Capture

“…In conclusion, we demonstrate the use of custom‐shape, flexible hydrogel microparticles for specific antibody‐based cell capture. We believe this approach has many advantages, including high‐throughput particle synthesis, easy functionalization with various probes, potential for synergistic use with microfluidic devices for downstream analysis of captured cells, and subsequent culture of isolated cells directly on particle substrates . As one example, our system may be advantageous for addressing the ongoing challenge of CTC heterogeneity, which makes efficient capture difficult and results in isolated cells that play different functional roles .…”