Membrane potential sensing: Material design and method development for single particle optical electrophysiology.

We review the development of "single" nanoparticle-based inorganic and organic voltage sensors, which can eventually become a viable tool for "non-genetic optogenetics." The voltage sensing is accomplished with optical imaging at the fast temporal response and high spatial resolutions in a large field of view. Inorganic voltage nanosensors utilize the Quantum Confined Stark Effect (QCSE) to sense local electric fields.

Optical probing of local membrane potential with fluorescent polystyrene beads.

The study of electrical activity in single cells and local circuits of excitable cells, such as neurons, requires an easy-to-use, high-throughput methodology that allows for the measurement of membrane potential. Investigating the electrical properties in specific subcompartments of neurons, or in a specific type of neurons, introduces additional complexity. An optical voltage-imaging technique that allows high spatial and temporal resolution could be an ideal solution.

Point-localized, site-specific membrane potential optical recording by single fluorescent nanodiscs.

Nanodisc technology was implemented as a platform for voltage nanosensors. A fluorescence (Förster) resonance energy transfer (FRET)- based voltage-sensing scheme employing fluorescent nanodiscs and the hydrophobic ion dipicrylamine was developed and utilized to optically record membrane potentials on the single-nanodisc level. Ensemble and single-nanosensor recordings were demonstrated for HEK293 cells and primary cortical neuron cells.

Weak Electromagnetic Fields Accelerate Fusion of Myoblasts.

Weak electromagnetic fields (WEF) alter Ca handling in skeletal muscle myotubes. Owing to the involvement of Ca in muscle development, we investigated whether WEF affects fusion of myoblasts in culture. Rat primary myoblast cultures were exposed to WEF (1.

Interfacing the Cell with "Biomimetic Membrane Proteins".

Integral membrane proteins mediate a myriad of cellular processes and are the target of many therapeutic drugs. Enhancement and extension of the functional scope of membrane proteins can be realized by membrane incorporation of engineered nanoparticles designed for specific diagnostic and therapeutic applications. In contrast to hydrophobic insertion of small amphiphilic molecules, delivery and membrane incorporation of particles on the nanometric scale poses a crucial barrier for technological development.

Pax6 is required for normal cell-cycle exit and the differentiation kinetics of retinal progenitor cells.

The coupling between cell-cycle exit and onset of differentiation is a common feature throughout the developing nervous system, but the mechanisms that link these processes are mostly unknown. Although the transcription factor Pax6 has been implicated in both proliferation and differentiation of multiple regions within the central nervous system (CNS), its contribution to the transition between these successive states remains elusive. To gain insight into the role of Pax6 during the transition from proliferating progenitors to differentiating precursors, we investigated cell-cycle and transcriptomic changes occurring in Pax6 (-) retinal progenitor cells (RPCs).