A Novel Terahertz-Based Metamaterial System for the Detection of Multidrug-Resistant Mycobacterium tuberculosis

BACKGROUND: Terahertz metamaterial is a label-free affinity sensor that is particularly sensitive to changes in the surface dielectric environment, so it can be used to detect protein molecules, human tissues, and drug reaction processes. This study aimed to construct a detection system for multidrug-resistant Mycobacterium tuberculosis (MTB) based on terahertz metamaterials. METHODS: Linear padlock probes (PLP) were designed to contain sequences complementary to the DNA sequences of drug-resistant MTB (target sequences), and linear PLP hybridizes to the target sequence to form a circular PLP. The primers fixed on the magnetic beads hybridize with the circular PLP to initiate rolling circle amplification (RCA). We placed RCA nucleic acid products on terahertz metamaterials for terahertz measurements. RESULTS: We determined the detection system primer concentration to be 15 μmol/L and the RCA reaction time to be 2 hours. Under the abovementioned optimal conditions, the minimum detection limits of the terahertz metamaterial detection system for the target sequences of katG315, rpoB531, and rpsL43 were 7.7 × 10-5 pmol/L, 1.03 × 10-5 pmol/L, and 1.3 × 10-4 pmol/L, respectively. CONCLUSIONS: This terahertz metamaterial-based detection system can achieve high-sensitivity and rapid detection of multiple drug-resistant MTB.