Label free NAPPA via nanogravimetry

Nanogravimetry label-free applications to the Nucleic Acid Programmed Protein Array technology is reviewed. DNA micro-arrays constitute a major advance in functional proteomics for the in situ generation of proteins micro arrays. The use of two different nanogravimetric technologies allows to investigate the kinetics during the in situ proteins expression. The first nanogravimetric apparatus is capable to detect frequency variations and protein production kinetics from four independent transducers driven in parallel, with a miniature flow-cell to follow each step of the protein expression protocol directly on the quartz. A software tool able to drive the signal acquisition and to analyze the acquired data was developed. First results on the in situ expression of proteins are reported. The second nanogravimetric instrumentation has been developed since very recently to account for viscoelastic behavior of protein films smoothly connected to the quartz crystal in terms of the quality factor. The system can detect also the crystal oscillations variations at expressing proteins in a liquid environment. The complex nature of these experiments is briefly discussed and preliminary results reported.