Optical Fiber DNA Biosensor With Temperature Monitoring Based on Double Microcavities Fabry–Perot Interference and Vernier Combined Effect

This article introduces a label-free DNA sensor based on the double microcavities Fabry–Perot (FP) interference and Vernier effect. The sensor can simultaneously monitor the temperature to avoid interference with the process of measuring DNA. The biosensor is composed of two open microcavities made of C-type optical fiber. One of the microcavities will is functionalized by the probe DNA (pDNA) to hybridize with complementary DNA (cDNA). And the other microcavity is filled with PDMS to realize temperature sensitivity. At the same time, the two cavities will form a Vernier effect, which is sensitive to both temperature and DNA. It is proven by experiments that the temperature sensitivity and refractive index (RI) sensitivity of the sensor are −2.79 nm/°C and −7122.63 nm/RIU, respectively. The proposed sensor has good specificity. cDNA sequence can bind well to given targets but hardly bind to noncomplementary DNA (non-cDNA) sequences. Moreover, the sensor offers some other benefits of high sensitivity, dual-parameter detection, real-time response, and simple fabrication. This is of great significance to solve the problem of the temperature sensitivity of biosensors.