Runhuai Yang

Development of automated patch clamp system for electrophysiology

In this paper, the development of an automated patch clamp system for cellular electrical information is reported. The system involves several developments that enable the following tasks: “pipette and cell localization”, “pipette engaging”, “gigaseal”, and “break-in”. The system enables us to engage the glass micro pipette automatically on the cell membrane, and perform whole cell recording on adherent cells. In a patch clamp experiment, the dynamic changes of resistance of the pipette were monitored, and a successful whole cell recording of a cell was demonstrated.

Multiplexed Optogenetic Stimulation of Neurons with Spectrum-Selective Upconversion Nanoparticles

Optical modulation of nervous system becomes increasingly popular as the wide adoption of optogenetics. For these applications, upconversion materials hold great promise as novel photonic elements. This study describes an upconversion based strategy for combinatorial neural stimulation both in vitro and in vivo by using spectrum-selective upconversion nanoparticles (UCNPs). NaYF4 based UCNPs are used to absorb near-infrared (NIR) energy and to emit visible light for stimulating neurons expressing different channelrhodopsin (ChR) proteins. The emission spectrum of the UCNPs is selectively tuned by different doping strategy (Tm3+ or Er3+ ) to match the responsive wavelength of ChR2 or C1V1. When the UCNPs are packaged into a glass microoptrode, and placed close to or in direct contact with neurons expressing ChR2 or C1V1, the cells can be reliably activated by NIR illumination at single cell level as well as network level, which is characterized by patch-clamping and multielectrode-array recording in culture primary neurons. Furthermore, the UCNP-based optrode is implanted into the brain of live rodents to achieve all-optical remote activation of brain tissues in mammalian animals. It is believed that this proof-of-concept study opens up completely new applications of upconversion materials for regulating physiological functions, especially in neuroscience research.

Development of the Electric Equivalent Model for the Cytoplasmic Microinjection of Small Adherent Cells

A novel approach utilizing current feedback for the cytoplasmic microinjection of biological cells is proposed. In order to realize the cytoplasmic microinjection on small adherent cells (diameter < 30 μm and thickness < 10 μm), an electrical model is built and analyzed according to the electrochemical properties of target cells. In this study, we have verified the effectiveness of the current measurement for monitoring the injection process and the study of ion channel activities for verifying the cell viability of the cells after the microinjection.

Analysis of electrode condition for whole cell recording

In this paper, an experimental study on the successful rate of using different types of pipettes for whole cell recording is reported. 5 types of pipettes have been designed and made. The procedure of whole cell recording has been analyzed, and the seal formation of and the rupture of patched membrane have been monitored. According to our research, the optimized value of pipette resistance is 15-30 MΩ for whole cell recording.

Design and Analysis of Electrical Resistance Feedback for Automated Patch Clamp on Adherent Cells

Conventional patch clamp techniques require complex manual work. Automated patch clamp systems have been recently developed to eliminate the need of manual handling, but these systems can only perform recordings on suspended cells and require cell dissociation for recordings on adherent cells. Here, we develop a systematic approach to apply electrical resistance feedback for automated patch clamp recording on adherent cells. By developing resistance thresholds in the electrical resistance feedback algorithm, the engaging condition of the adherent cell was automatically determined. We analyze the critical parameters that affect the performance of the automated patch clamp recording. By using the new algorithm for automated engaging and formation, the cell-attached and whole-cell recordings on adherent cells were performed in less than 5 min with the yield of over 70%. The system is designed to directly measure the adherent cells and so, cell dissociation (e.g., trypsin treatment and cell scrapers) can be avoided and the cell properties can be maintained. By using the system, the efficiency of performing the automated patch clamp on adherent cells can be improved, which is of great importance in electrophysiological studies of single cells.

Analysis of visual-based micromanipulation for patch clamp recording

Recent advances in patch clamp system have demonstrated that a visual-based micromanipulation strategy can benefit to perform electrophysiological recording automatically. In this paper, the design and implementation of a micromanipulation system with the visual-based identification are reported. The system is able to manipulate a patch clamp pipette to the position of target cells automatically. The calibration and alignment method based on the coordinate frames of the camera and micromanipulator are introduced. Some parameters such as angle of rotation matrix and displacement errors are analyzed.

Development of a nanorobotic station for electrophysiology under nanomechanical stimulation

In this paper, the development of a nanorobotic station for acquisition of cellular electrical and mechanical information is reported. This station involves the development of a nanomanipulation platform and a planar patch-clamp module. The nanomanipulation platform not only enables the observation of biological cells, but also has the ability to give a precise pico-Newton force stimulus on a certain position of cells. The membrane potential of cells can be recorded by the patch clamp module. The module also has the ability to generate electric stimulus to the biological cells. This station provides a method to research both mechanical and electrical properties of living cells.