Detection of MPT-64 protein in pleural tuberculosis cases by magnetic bead-gold nanoparticle-PCR amplified immunoassay.

Aim: Diagnosis of pleural tuberculosis (TB) is challenging; thus, an efficient method is urgently needed.

Methods: We developed a magnetic-bead-gold nanoparticle-PCR amplified immunoassay (MB-AuNP-I-PCR, liquid system) to detect the Mycobacterium tuberculosis MPT-64 protein in pleural TB patients. AuNPs functionalized with detection antibodies/oligonucleotides were characterized by UV-vis spectroscopy, Transmission/Scanning electron microscopy, Fourier-transform infrared spectrometer, ELISA, and PCR, whereas MBs conjugated with detection antibodies were validated by magneto-ELISA/UV-vis spectroscopy.

Results: We utilized the MB-AuNP-I-PCR for MPT-64 detection in 99 clinical specimens which displayed 85.2% sensitivity and 97.8% specificity to diagnose pleural TB cases. Markedly, the sensitivity achieved by MB-AuNP-I-PCR was noticeably higher (p < 0.01) than magneto-ELISA and GeneXpert.

Conclusion: This is a preliminary report to diagnose pleural TB cases by MB-AuNP-I-PCR with promising results that require further corroboration in a higher number of specimens.