BV-2 microglial cells sense micro-nanotextured silicon surface topology.

Artificial biomimetic substrates provide useful models for studying cell adhesion, signaling, and differentiation. This article describes biological interactions with a new type of tunable, micro-nanotextured silicon substrate, generated by irradiation of a hydrogenated amorphous silicon film with a large beam, excimer laser (248 nm). In this study, we demonstrate that BV-2 microglial cells can sense differences in laser processed silicon surface topology over the range of 30 nm to 2 µm, where they undergo marked morphogenic changes with increasing feature size. The cells adopt a more elongated shape in the presence of the modified surface structure and exhibit increased levels of actin-rich microdomains, suggesting enhanced adhesion. The excimer laser modification of hydrogenated amorphous silicon to generate micro-nanostructures realizes large area benefits as well as providing a biomaterial where the external and internal structure can be altered and tuned for various applications.

Miniaturized optoelectronic tweezers controlled by GaN micro-pixel light emitting diode arrays.

A novel, miniaturized optoelectronic tweezers (OET) system has been developed using a CMOS-controlled GaN micro-pixelated light emitting diode (LED) array as an integrated micro-light source. The micro-LED array offers spatio-temporal and intensity control of the emission pattern, enabling the creation of reconfigurable virtual electrodes to achieve OET. In order to analyse the mechanism responsible for particle manipulation in this OET system, the average particle velocity, electrical field and forces applied to the particles were characterized and simulated. The capability of this miniaturized OET system for manipulating and trapping multiple particles including polystyrene beads and live cells has been successfully demonstrated.