Dynamically directing cell organization via micro-hump structure patterned cell-adhered interfaces

Straightforward Cell Patterning with Ultra-Low Background Using Polydimethylsiloxane Through-Hole Membranes

Micropatterning is becoming an increasingly popular tool to realize microscale cell positioning and decipher cell activities and functions under specific microenvironments. However, a facile methodology for building a highly precise cell pattern still remains challenging. In this study, A simple and straightforward method for stable and efficient cell patterning with ultra-low background using polydimethylsiloxane through-hole membranes is developed. The patterning process is conveniently on the basis of membrane peeling and routine pipetting. Cell patterning in high quality involving over 97% patterning coincidence and zero residue on the background is achieved. The high repeatability and stability of the established method for multiple types of cell arrangements with different spatial profiles is demonstrated. The customizable cell patterning with ultra-low background and high diversity is confirmed to be quite feasible and reliable. Furthermore, the applicability of the patterning method for investigating the fundamental cell activities is also verified experimentally. The authors believe this microengineering advancement has valuable applications in many microscale cell manipulation-associated research fields including cell biology, cell engineering, cell imaging, and cell sensing.

The Use of Small-Molecule Compounds for Cell Adhesion and Migration in Regenerative Medicine

Cell adhesion is essential for cell survival, communication, and regulation, and it is of fundamental importance in the development and maintenance of tissues. Cell adhesion has been widely explored due to its many important roles in the fields of tissue regenerative engineering and cell biology. This is because the mechanical interactions between a cell and its extracellular matrix (ECM) can influence and control cell behavior and function. Currently, biomaterials for regenerative medicine have been heavily investigated as substrates for promoting a cells' adhesive properties and subsequent proliferation, tissue differentiation, and maturation. Specifically, the manipulation of biomaterial surfaces using ECM coatings such as fibronectin extracted from animal-derived ECM have contributed significantly to tissue regenerative engineering as well as basic cell biology research. Additionally, synthetic and natural bioadhesive agents with pronounced abilities to enhance adhesion in numerous biological components and molecules have also been assessed in the field of tissue regeneration. Research into the use of facilitative bioadhesives has aimed to further optimize the biocompatibility, biodegradability, toxicity levels, and crosslinking duration of bioadhesive materials for improved targeted delivery and tissue repair. However, the restrictive drawbacks of some of these bioadhesive and animal-derived materials include the potential risk of disease transmission, immunogenicity, poor reproducibility, impurities, and instability. Therefore, it is necessary for alternative strategies to be sought out to improve the quality of cell adhesion to biomaterials. One promising strategy involves the use of cell-adhesive small molecules. Small molecules are relatively inexpensive, stable, and low-molecular-weight (<1000 Da) compounds with great potential to serve as efficient alternatives to conventional bioadhesives, ECM proteins, and other derived peptides. Over the past few years, a number of cell adhesive small molecules with the potential for tissue regeneration have been reported. In this review, we discuss the current progress using cell adhesive small molecules to regulate tissue regeneration.

Density Regulation and Localization of Cell Clusters by Self-Assembled Femtosecond-Laser-Fabricated Micropillar Arrays

Tumor cell clusters of varying sizes and densities have different metastatic potentials. Three-dimensional (3D) patterned structures with rational topographical and mechanical properties are capable of guiding the 3D clustering of tumor cells. In this study, single femtosecond laser pulses were used to fabricate individual high-aspect-ratio micropillars via two-photon polymerization (TPP). By combining this approach with capillary-force self-assembly, complex 3D microstructure patterns were constructed with a high efficiency. The microstructures were able to regulate the formation of cell clusters at different cell seeding densities and direct self-guided 3D assembly of cell clusters of various sizes and densities. Localization of cell clusters was achieved using grid-indexed samples to address individual cell clusters, which holds great promise for in situ cell cluster culture and monitoring and for applications such as RNA sequencing of cell clusters.

Rapid generation of hybrid biochemical/mechanical cues in heterogeneous droplets for high-throughput screening of cellular responses

Cells in their native microenvironment are subjected to varying combinations of biochemical cues and mechanical cues in a wide range. Although many signaling pathways have been found to be responsive for extracellular cues, little is known about how biochemical cues crosstalk with mechanical cues in a complex microenvironment. Here, we introduced heterogeneous droplets on a microchip, which were rapidly assembled by combining wettability-patterned microchip and programmed droplet manipulations, for a high-throughput cell screening of the varying combinations of biochemical cues and mechanical cues. This platform constructed a heterogeneous droplet/microgel array with orthogonal gradual chemicals and materials, which was further applied to analyze the cellular Wnt/β-catenin signaling in response to varying combinations of Wnt ligands and substrate stiffness. Thus, this device provides a powerful multiplexed bioassay platform for drug development, tissue engineering, and stem cell screening.

Straightforward neuron micropatterning and neuronal network construction on cell-repellent polydimethylsiloxane using microfluidics-guided functionalized Pluronic modification

Neuronal cell microengineering involving micropatterning and polydimethylsiloxane (PDMS) microfluidics enables promising advances in microscale neuron control. However, a facile methodology for the precise and effective manipulation of neurons on a cell-repellent PDMS substrate remains challenging. Herein, a simple and straightforward strategy for neuronal cell patterning and neuronal network construction on PDMS based on microfluidics-assisted modification of functionalized Pluronic is described. The cell patterning process simply involves a one-step microfluidic modification and routine in vitro culture. It is demonstrated that multiple types of neuronal cell arrangements with various spatial profiles can be conveniently produced using this patterning tool. The precise control of neuronal cells with high patterning fidelity up to single cell resolution, as well as high adhesion and differentiation, is achieved too. Furthermore, neuronal network construction using the respective cell population and single cell patterning prove to be applicable. This achievement provides a convenient and feasible methodology for engineering neuronal cells on PDMS substrates, which will be useful for applications in many neuron-related microscale analytical research fields, including cell engineering, neurobiology, neuropharmacology, and neuronal sensing.