Squeezed flow preconcentration for probe tip biosensors.
The preconcentration of analytes improves sensing using probe tips. In this work, we report a method based on creating a squeeze flow between a cylinder and circular coverslip to preconcentrate material at the liquid-gas interface while allowing a probe tip to be readily inserted there. In verification tests using enhanced green fluorescent protein, this capacity is proven. We estimated a 9.7 times increase in probability for fluorophores to be picked up at the tip using inference from fluorescence intensity distributions found. The method is expeditious, simple, and inexpensive, and it does not require any electrical energy source to operate.