Surface Modifications of Support Partitions for Stabilizing Biomimetic Membrane Arrays

Black lipid membrane (BLM) formation across apertures in an ethylene tetra-fluoroethylene (ETFE) partition separating two aqueous compartments is an established technique for the creation of biomimetic membranes. Recently multi-aperture BLM arrays have attracted interest and in order to increase BLM array stability we studied the effect of covalently modifying the partition substrate using surface plasma polymerization with hydrophobic n-hexene, 1-decene and hexamethyldisiloxane (HMDSO) as modification groups.

Average lifetimes across singlesided HMDSO modified partitions or using 1-decene modified partitions were similar and significantly lower than for arrays formed using untreated ETFE partitions. For single side n-hexene modification average membrane array lifetimes were not significantly changed compared to untreated ETFE.

Double-sided n-hexene modification greatly improved average membrane array lifetimes compared to membrane arrays formed across untreated ETFE partitions. n-hexene modifications resulted in BLM membrane arrays which over time developed significantly lower conductance (Gm) and higher capacitance (Cm) values compared to the other membranes with the strongest effect for double sided modification. n-hexene modification is evident as a change in surface energy whereas the surface roughness does not change significantly.

The concomitant low Gm and high Cm values for BLM arrays formed using double-sided n-hexene modification enable transmembrane ionic current recordings with a high signal-to-noise (s/n) ratio. We demonstratesd this by reconstituting gA and α-hemolysin (α-HL) into BLM arrays. The improvement in membrane array lifetime and s/n ratio demonstrates that surface plasma polymerization of the supporting partition can be used to increase the stability of biomimetic membrane arrays.