Special RCA based sensitive point-of-care detection of HPV mRNA for cervical cancer screening

Abstract

Developing the sensitive point-of-care testing (POCT) of oncogenic nucleic acids from human papillomavirus (HPV) infection is essential in preventing cervical cancer, especially in resource-limited settings. Rolling circle amplification (RCA) is attractive in achieving POCT via nucleic acid-based aggregation under isothermal conditions. However, the influence of RCA product structure on the aggregation remains unexplored resulting in limited sensitivity. Here, a minimum secondary structured RCA technique (MSS-RCA) is developed by designing a unique circular template, demonstrating significantly enhanced detection sensitivity with only one amplification step and one primer under isothermal conditions. The amplification efficiency of MSS-RCA could be kinetically manipulated by controlling the secondary structure of the circular template. Introducing the invertase probe to MSS-RCA, HPV16 E6/E7 nucleic acid target was detected with a personal glucose meter (PGM) with a sensitivity of 5 fm (50 zmol in 10 µL). This integrated MSS-RCA-PGM detection system was successfully applied to detect HPV16 E6/E7 mRNA extracted from 54 cervical swab samples reaching a positive predictive value of 100.00% and negative predictive values of 96.00% (77.77% to 99.40%, 95% CI). MSS-RCA-PGM provides a sensitive POCT platform for the detection of nucleic acid biomarkers for screening of cervical cancer or other diseases.