Lab on a Single Fiber: A Three-Parameter Sensor Based on Triple-SPR for One-to-one Detection of DNA, pH and Temperature

In order to realize the one-to-one correspondence between outputs and inputs in the multiparameter detection field, a multiparameter DNA hybridization sensor with temperature and pH detection channels based on a fiber-based triple surface plasmon resonance (Triple-SPR) effect is demonstrated in this paper. Compared with previous works, the significant innovation of this paper is the independent temperature testing and pH testing channels implemented based on a single fiber optic structure, and the high-sensitivity DNA hybridization detection channel. Polydimethylsiloxane and the self-assembled materials formed by polyacrylic acid (PAA) and chitosan (CS) are used for the real-time detection of temperature and pH. With the help of these two materials, the instantaneous response of the Triple-SPR sensor to temperature and pH has been realized, and the response times (RT) are less than 1   s and 20   s, respectively. After the modification of probe DNA (pDNA), the selective detection of complementary DNA (cDNA) is achieved. The sensitivity and detection limit (DL) reaches 0.09   nm/(nmol/L) and 3.69 nmol/L, respectively. The experimental results demonstrate that an approximately one-to-one correspondence exists between inputs and outputs. The output signals can be used to provide feedback signals for achieving stable temperature and pH environments. The advantages of multi-parameter independent detection, high-sensitivity as well as fast response of the fiber-based Triple-SPR sensing technology are of great significance in the field of future multi-parameter sensing, compensated detection as well as real-time bio-monitoring.