Nanoparticle-Based Biosensing of Tuberculosis, an Affordable and Practical Alternative to Current Methods

• Published in: Biosensors (Basel) 2018-12, Vol.9 (1), p.1
• Main Authors: Bhusal, Nirajan, Shrestha, Sunaina, Pote, Nisha, Alocilja, Evangelyn C
• Format: Article
• Language: English
• Subjects: acid-fast bacilli; Bacilli; Biosensing Techniques; Biosensors; Clumps; Colorimetric assay; Colorimetry; Drug resistance; Expert MTB/RIF; Glycan; Glycoproteins; Humans; Magnetic properties; Methods; Microscopy; Nanoparticles; Nanoparticles - chemistry; Nanotechnology; Particle Size; Patients; Point-of-Care Systems; pulmonary TB; Rural areas; Rural communities; Sensitivity and Specificity; Sputum; Sputum - diagnostic imaging; Sputum - microbiology; sputum microscopy; Statistical analysis; Statistical methods; Surface Properties; Tuberculosis; Tuberculosis - diagnosis; Tuberculosis - microbiology
• ISSN: 2079-6374; 2079-6374
• DOI: 10.3390/bios9010001

Access to community-based point-of-care, low-cost, and sensitive tuberculosis (TB) diagnostics remains an unmet need. The objective of this study was to combine principles in nanotechnology, TB biology, glycochemistry, and engineering, for the development of a nanoparticle-based colorimetric biosensing assay (NCBA) to quickly and inexpensively detect acid-fast bacilli (AFB) in sputum samples. In NCBA, the isolation of AFB from sputum samples was accomplished through glycan-coated magnetic nanoparticles (GMNP) interacting with AFB and then using a simple magnet to separate the GMNP-AFB complex. Acid-fastness and cording properties of mycobacteria were utilized to provide visually observable red-stained clumps of bacteria that were surrounded by brown nanoparticles under a light microscope on prepared smears. The NCBA technique was compared against sputum smear microscopy (SSM) and Xpert MTB/RIF in 500 samples from patients that were suspected to have TB. Statistical analysis showed that NCBA had sensitivity and specificity performances in perfect agreement with Xpert MTB/RIF as gold standard for all 500 samples. SSM had a sensitivity of 40% for the same samples. NCBA technique yielded full agreement in terms of sensitivity and specificity with the Xpert MTB/RIF in 500 samples. The method is completed in 10⁻20 min through a simple process at an estimated cost of $0.10 per test. Implementation of NCBA in rural communities would help to increase case finding and case notification, and would support programs against drug-resistance. Its use at the first point-of-contact by patients in the healthcare system would facilitate quick treatment in a single clinical encounter, thus supporting the global "End TB Strategy" by 2035.