Just came across another paper on Nanowire Biosensor in PNAS (published online on December 23, 2009), this time for detecting protein-protein interactions. Briefly, nanowire biosensor is functionalized with glutathione followed by binding of GST (Glutathione-S- Transferase) fused calmodulin. Calmodulin functionalized nanowire biosensor responds in linear fashion to Troponin concentration in range of 10nM to 1uM.
Frankly speaking, I have no idea why is this paper in PNAS. According to authors-“This sensitive nanowire transistor can serve as a high-throughput biosensor and can also substitute for immunoprecipitation methods used in the identification of interacting proteins.” But I do not see any example in this paper that indicates that nanowire biosensor can match high-throughput (1000’s of protein-protein interactions) of protein arrays as shown by Mike Snyder (of Yale and now at Stanford) and Josh Labaer (of Harvard now at Arizona) and also commercially available kits from Invitrogen (now Life Sciences). Neither, do I see any comparison with established label free biosensing platforms like Biacore or anything else (see my list of commercial label free biosensors in Resources page). Finally, nanowire sensor as substitute for immunoprecipitation(IPs) or traditional pulldowns – give me a break! Pull downs/IPs can be done for few dollars an experiment compared with $$$$ for nanowire biosensors.
My thoughts! Let me know if you think differently.