Samples containing RNA and DNA lie at the heart of all biopsy techniques. Biosensors that can enhance the concentration of RNA and DNA in these samples, improving the detection sensitivity of these techniques, have the potential to revolutionize the field of microfluidics and diagnostics. In an effort to reduce the invasiveness and sheer complexity of laboratory procedures inherent to surgical biopsy, we are investigating techniques to conduct liquid biopsies on chips varying from millimeters to a few square centimeters in size, that are capable of detecting molecules of interest, such as proteins, in very small volumes.