Objective   To study the feasibility of combination of  “RecA protein-complementary single strand DNA” probe and bis-PNA/dsDNA complexes as the biological signal amplification system for the improvement of the sensitivity of leaky surface acoustic wave bis-peptide nucleic acid biosensor.     Methods   Bis-PNA probe for detecting human papilloma virus (HPV) was immobilized on the surface of gold membrane of the detection channel. After the probe was hybridized with the corresponding target DNA completely

different concentrations of “RecA protein-complementary single strand DNA probe” were added to react with bis-PNA/dsDNA complexes.     Results   The phase shift value was (11.74±1.03) deg at the concentration of 45 μg/ml of RecA protein

significantly different as compared with other concentrations (P0.01). At the optimal concentration of RecA protein

the phase shift value was (10.71±0.73) deg at the concentration of 2.5 mmol/L of ATPγS

significantly different as compared with other concentrations (P0.01).     Conclusion   Combination of “RecA protein-complementary single strand DNA probe” and bis-PNA/dsDNA complexes contributes to effective improvement of the sensitivity and significantly shortened detection time.