LAUSR

Recent findings have thrust poly (ADP-ribose) polymerase-1 (PARP-1) into the limelight as potential biomarker and chemotherapeutic target for cancer. Thus, a sensitive method for detection of PARP-1 is necessary for early diagnosis of cancer and drug development. However, the poor electrochemical and optical activity of PARP-1 and its product PAR limited researchers to develop more methods. Here, we developed an efficient method for the determination of PARP-1 by using quartz crystal microbalance (QCM) since it is mass-sensitive. Once activated by the specific DNA, PARP-1 cleaves nicotinamideadenine dinucleotide (NAD+) into nicotinamide and ADP-ribose to synthesize a hyper-branched poly (ADP-ribose) polymer (PAR). Although QCM is mass-sensitive, it is not sensitive enough to discern PAR effectively. So, positively charged CTAB-coated GNRs were introduced to increase the frequency change significantly because of the strong electrostatic interaction between them with negatively charged PAR. PARP-1 ranging from 0.06 nM to 3 nM can be facilely detected with a low detection limit of 0.04 nM. The strategy has been used to evaluate PARP-1 inhibitors and to detect PARP-1 activity in real cancer cells lysate with satisfactory results, indicating that it was a promising candidate for clinical diagnosis and drug screening in the future.