In a research article published in the September issue of Nature Biotechnology, Arun Majumdar, professor of mechanical engineering at Berkeley, and coauthors at Oak Ridge National Laboratory in Oak Ridge, Tenn., the University of Southern California in Los Angeles, and the Lawrence Berkeley National Laboratory at UC-Berkeley, describe a system to quantify prostate-specific antigen (PSA), a prostate cancer protein marker.
The PSA test uses a cantilever 200 mm long and 0.5 mm wide, one side of which is coated with gold and conjugated to an antibody that recognizes PSA. Majumdar and his colleagues incubated the cantilever, which is a diving board-like device, with a simulated human serum that contained high concentrations of human plasminogen, human serum albumin, or bovine serum albumin, with varying concentrations of PSA. When the antibodies on the cantilever captured the PSA in the solution, the device bent a few nanometers in height. A laser beam aimed ...
