Photothermal triggered clinical swab point-of-care testing diagnostics: fluorescence-pressure multi-signal readout detection of cervical cancer biomarker

Abstract

In this protocol, a photothermal triggered multi-signal readout point-of-care testing (POCT) was established in a multifunctional clinical vagina swab for Human papillomavirus type 16 E6 (E6 protein) determination. Particularly, a portable vagina swab was employed as a sensing substrate integrated collection and analysis of samples. The composite probe SiC-CS@Ag with the chitosan (CS) decorated silicon carbide nanoparticles (SiC NPs) as a label was bounded to the swab via competitive reaction. To transfer recognition events into detectable signals, a flexible fluorescence -temperature indicator (FLTI) with thermal-responsive fluorescence capability was assembled on swab surface followed by sealing it into a home-made tiny pressure device and H2O2 as a signal reporter was introduced. Under near-infrared (NIR) laser expose, remarkable photothermal effect from SiC-CS@Ag caused notable temperature elevation, which lead to significant fluorescence (FL) quenching on FLTI. Meanwhile, increased temperature also enhance the catalase-like activity of SiC-CS@Ag toward H2O2 decomposition that cause significant pressure elevation. This bioassay realized sensitive target detection in the linear ranger from 10-6 ng/mL to 1 ng/mL with detection limits of 1.60 × 10-6 ng/mL. Such a photothermal mediated multi-signal readout sensing platform not only provides rapid and precise methodologies for biomarker detection, but also enriches strategies for POCT and boosted its application for early diagnosis of malignant diseases in remote areas.