Published online by Cambridge University Press: 01 February 2011
We have encapsulated lipid bilayer membranes within a polyethylene glycol dimethacrylate hydrogel (PEG-DMA). These hydrogel encapsulated membranes (HEMs) are significantly longer-lived and more mechanically stable than traditional lipid membranes. Over 50 attempts, HEMs usually remained intact for over 48 hours, and some lasted up to 5 days. The electrical characteristics of the HEMs were consistently stable over this period of time. The approximate thickness of the HEM was measured to be 4.7±0.5 nm (n=25), consistent with a lipid bilayer. The resistance of the HEM remained over 10 GΩ over the period of electrical measurement. Simultaneous electrical and optical measurements showed that HEMs have unusual mechanical stability, whereas free-standing lipid membranes are typically susceptible to mechanical perturbation. The HEMs could withstand much greater applied pressures than unsupported membranes. In situ electrical and optical monitoring of the HEMs showed that the gel made intimate contact with the membrane, suggesting that direct mechanical support of the bilayer is the mechanism of membrane stabilization. Single channels of alpha-hemolysin, were incorporated into HEMs and continuously measured for over 4 days. Finally, combination of the HEM with an automated membrane microfluidic formation process is proposed as a prototype platform for high throughput drug screening or small molecule sensing.