Ultrathin glass fiber microprobe for electroporation of arbitrary selected cell groups

A Gaussian to Vector Vortex Beam Generator with a Programmable State of Polarization

We study an optical device designed for converting the polarized Gaussian beam into an optical vortex of tunable polarization. The proposed device comprised a set of three specially prepared nematic liquid crystal cells and a nano-spherical phase plate fabricated from two types of glass nanotubes. This device generates a high-quality optical vortex possessing one of the multiple polarization states from the uniformly polarized input Gaussian beam. Its small size, simplicity of operation, and electrical steering can be easily integrated into the laboratory and industrial systems, making it a promising alternative to passive vortex retarders and spatial light modulators.

Laser Machined Fiber-based Microprobe: Application in Microscale Electroporation

Microscale electroporation devices are mostly restricted to in vitro experiments (i.e., microchannel and microcapillary). Novel fiber-based microprobes can enable in vivo microscale electroporation and arbitrarily select the cell groups of interest to electroporate. We developed a flexible, fiber-based microscale electroporation device through a thermal drawing process and femtosecond laser micromachining techniques. The fiber consists of four copper electrodes (80 μm), one microfluidic channel (30 μm), and has an overall diameter of 400 μm. The dimensions of the exposed electrodes and channel were customizable through a delicate femtosecond laser setup. The feasibility of the fiber probe was validated through numerical simulations and in vitro experiments. Successful reversible and irreversible microscale electroporation was observed in a 3D collagen scaffold (seeded with U251 human glioma cells) using fluorescent staining. The ablation regions were estimated by performing the covariance error ellipse method and compared with the numerical simulations. The computational and experimental results of the working fiber-based microprobe suggest the feasibility of in vivo microscale electroporation in space-sensitive areas, such as the deep brain.