Photo-Voltage Transients for Real-Time Analysis of the Interactions between Molecules and Membranes

Abstract

The interfacial dynamic interactions between molecules and cell membranes are critical in many basic biological processes. An effective method for sensitive, real-time, and noninvasive monitoring of these processes is needed. Here, using photoelectric responses of a silicon wafer, the charge–discharge processes of a phospholipid membrane are recorded as voltage transients, which directly reflect the instant structure and properties of the membrane. Based on the time evolution of the as-calculated charge relaxation time constant, dynamic changes in the membrane structure under molecular actions can be analyzed. The swelling and Tween 20 action processes on both mono- and multilayered membranes were taken as examples, which showed more mechanism details in comparison to the traditional X-ray diffraction or fluorescence imaging tests. Our method provides a promising solution for label-free, noninvasive, and real-time studies on the dynamic interactions between molecules and a membrane.

Assembly-Induced Membrane Selectivity of Artificial Model Peptides through Entropy–Enthalpy Competition

“…The charge and discharge process of the SLB is simultaneously recorded as deformed square-wave pulses that depend on membrane properties. The voltage pulse can be quantitatively characterized as the relaxation time constant τ . Thus, the real-time variation of membrane properties due to peptide actions is reflected by the time evolution of τ after adding peptides into solution.…”

“…The membrane activity of K7W6 was further investigated using photovoltage transient testing, a recently developed method capable of sensitively detecting real-time changes in the membrane structure, particularly the formation of transmembrane defects. − The working electrode consists of a silicon wafer substrate and a supported lipid bilayer (SLB) membrane, represented by a variable capacitor C 1 and a variable resistor R 1 in parallel in the simplified circuit (Figure g). When applying square-wave modulated light ( e.g.…”

“…The voltage pulse can be quantitatively characterized as the relaxation time constant τ. 44 Thus, the real-time variation of membrane properties due to peptide actions is reflected by the time evolution of τ after adding peptides into solution.…”

Real-time monitoring the staged interactions between cationic surfactants and a phospholipid bilayer membrane

“…Based on monitoring the charging and discharging of electrons in a membrane with time, this method provides information on time and the molecular mechanism of phase transitions occurring on the membrane. 30 Now, in this work, this photo-voltage transient method was further improved to monitor the cationic surfactant-induced perturbation to a membrane.…”