A Microfluidic Platform Containing Sidewall Microgrooves for Cell Positioning and Trapping.

Microfluidic channels enable the control of cell positioning and the capturing of cells for high-throughput screening and other cellular applications. In this paper, a simple microfluidic platform is proposed for capturing small volumes of cells using sidewall microgrooves. The cell docking patterns in the channels containing sidewall microgroove are also studied.

Carbon-nanotube-embedded hydrogel sheets for engineering cardiac constructs and bioactuators.

We engineered functional cardiac patches by seeding neonatal rat cardiomyocytes onto carbon nanotube (CNT)-incorporated photo-cross-linkable gelatin methacrylate (GelMA) hydrogels. The resulting cardiac constructs showed excellent mechanical integrity and advanced electrophysiological functions. Specifically, myocardial tissues cultured on 50 μm thick CNT-GelMA showed 3 times higher spontaneous synchronous beating rates and 85% lower excitation threshold, compared to those cultured on pristine GelMA hydrogels.

Generating nonlinear concentration gradients in microfluidic devices for cell studies.

We describe a microfluidic device for generating nonlinear (exponential and sigmoidal) concentration gradients, coupled with a microwell array for cell storage and analysis. The device has two inputs for coflowing multiple aqueous solutions, a main coflow channel and an asymmetrical grid of fluidic channels that allows the two solutions to combine at intersection points without fully mixing. Due to this asymmetry and diffusion of the two species in the coflow channel, varying amounts of the two solutions enter each fluidic path.

Controlling the porosity of fibrous scaffolds by modulating the fiber diameter and packing density.

Porosity has been shown to be a key determinant of the success of tissue engineered scaffolds. A high degree of porosity and an appropriate pore size are necessary to provide adequate space for cell spreading and migration as well as to allow for proper exchange of nutrients and waste between the scaffold and the surrounding environment. Electrospun scaffolds offer an attractive approach for mimicking the natural extracellular matrix (ECM) for tissue engineering applications.

Directed assembly of cell-laden hydrogels for engineering functional tissues.

Tissue engineering aims to develop functionalized tissues for organ replacement or restoration. Biodegradable scaffolds have been used in tissue engineering to support cell growth and maintain mechanical and biological properties of tissue constructs. Ideally cells on these scaffolds adhere, proliferate, and deposit matrix at a rate that is consistent with scaffold degradation.

Interface-directed self-assembly of cell-laden microgels.

Cell-laden hydrogels show great promise for creating engineered tissues. However, a major shortcoming with these systems has been the inability to fabricate structures with controlled micrometer-scale features on a biologically relevant length scale. In this Full Paper, a rapid method is demonstrated for creating centimeter-scale, cell-laden hydrogels through the assembly of shape-controlled microgels or a liquid-air interface.

Rapid generation of spatially and temporally controllable long-range concentration gradients in a microfluidic device.

The ability to rapidly generate concentration gradients of diffusible molecules has important applications in many chemical and biological studies. Here we established spatially and temporally controllable concentration gradients of molecules (i.e.

Cell docking in double grooves in a microfluidic channel.

Microstructures that generate shear-protected regions in microchannels can rapidly immobilize cells for cell-based biosensing and drug screening. Here, a two-step fabrication method is used to generate double microgrooves with various depth ratios to achieve controlled double-level cell patterning while still providing shear protection. Six microgroove geometries are fabricated with different groove widths and depth ratios.

Method of Bottom-Up Directed Assembly of Cell-Laden Microgels.

The paper describes a protocol to fabricate cell-laden microgel assemblies with pre-defined micro-architecture and complexity by a bottom-up approach, which can be used for tissue engineering applications. The assembly process was driven by the hydrophobic effect in the water/oil interface. By agitating hydrophilic microgels in hydrophobic medium, the shape-controlled microgel units assemble in an organized manner to locally minimize the interaction free energy (the surface area exposed to the oil).