Self-assembly of bilayer lipid membrane at multiwalled carbon nanotubes towards the development of photo-switched functional device

Bilayer lipid membrane (BLM) was self-assembled on a uniquely fabricated hydrophilic surface, containing N atoms from the carbon source of ethylene amine, of the multi-walled carbon nanotubes (MWNTs) to form the BLM/MWNTs nanocomposites. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and photoelectric experiments were taken to study the properties of the BLM/MWNTs nanocomposites. The thickness of the BLM, which was calculated from the CV data obtained at BLM/MWNTs electrode, turned out to be 4.38 nm, suggesting that the lipid self-assembled at the nanotubes surface was consistent with a bilayer structure. C60-incorporated BLM could also be self-assembled at the nanotubes surface (C60-BLM/MWNTs). The formation of BLM on the MWNTs surface blocked the diffusion of [Fe(CN)6]3/4− redox ions across BLM to the MWNTs electrode as no redox current was observed by CV measurement, whereas the incorporation of the electron mediator, C60, resumed a pair of redox peaks at C60-BLMs/MWNTs electrode. Moreover, the incorporation of C60 led to a four order of magnitude reduction of the resistance of C60-BLM/MWNTs (369.3 Ω) than that of BLM/MWNTs (3.238 × 106 Ω). MWNTs electrode exhibited an intrinsic cathodic photocurrent (166 μA cm−2) while BLM/MWNTs electrode blocked photocurrent response of the MWNTs. Interestingly, C60-BLM/MWNTs electrode resumed partial photoelectric properties (photo current: 65 μA cm−2) due to the electron mediation effect of C60 incorporated into the lipid membrane. As a result, the novel self-assembled BLM/MWNTs nanocomposites provided a simple yet useful model to study the C60-mediated photoelectric properties of the BLM/MWNTs which may be applicable to develop new biosensors and molecular devices.