BSA as additive: A simple strategy for practical applications of PNA in bioanalysis

Application of peptide nucleic acid (PNA) in bioanalysis has been limited due to its nonspecific adsorption onto hydrophobic surface in spite of favorable properties such as higher chemical/biological stability, specificity and binding affinity towards target nucleic acids compared to natural nucleic acid probes. Herein, we employed BSA in PNA application to enhance the stability of PNA in hydrophobic containers and improve the sensing performance of the DNA sensor based on graphene oxide (GO) and PNA. Addition of 0.01% BSA in a PNA solution effectively prevented the adsorption of PNA on hydrophobic surface and increased the portion of the effective PNA strands for target binding without interfering duplex formation with a complementary target sequence. In the GO based biosensor using PNA, BSA interrupted the unfavorable adsorption of PNA/DNA duplex on GO surface, while allowing the adsorption of ssPNA, resulting in improvement of the performance of the DNA sensor system by reducing the detection limit by 90-folds.