We have recently reported a new NSOM/AFM tip design that has the potential to circumvent many of the problems that currently plague the conventional fiber optic NSOM probes. The idea revolves around the use of focused ion beam (FIB) instrumentation to sculpt a small glass sphere that has been attached to the end of a conventional AFM cantilever. Once coated with aluminum, an aperture is cut into the end of the tip using an FIB to provide a well-defined aperture for light delivery.
Here we show evidence that the addition of 11wt.% SP-B1-25 to monolayers of palmitic acid induces large density fluctuations in the membrane on macroscopic length scales, a signature of critical behavior. The implications of this observation may be relevant to the design of novel treatments for RDS.