A modular paper-and-plastic device for tuberculosis nucleic acid amplification testing in limited-resource settings

Area of Science:

• Biotechnology
• Molecular Diagnostics
• Medical Devices

Background:

• Tuberculosis (TB) remains a significant global health challenge, necessitating accessible and affordable diagnostic tools.
• Current molecular diagnostic methods often require specialized equipment and trained personnel, limiting their use in low-resource settings.

Purpose of the Study:

• To develop and evaluate a prototype for rapid, inexpensive, and point-of-care-compatible nucleic acid amplification tests (NAATs) for tuberculosis (TB).
• To assess the feasibility of using a paper-based, isothermal amplification assay for DNA detection compatible with mobile technology.

Main Methods:

• Development of the fluorescent isothermal paper-and-plastic NAAT (FLIPP-NAAT) utilizing loop-mediated isothermal amplification (LAMP) for DNA detection.
• Integration of an inexpensive imaging platform for filter-free fluorescence detection using a cell-phone camera.
• Evaluation of FLIPP-NAAT performance using Mycobacterium tuberculosis (Mtb) gDNA and clinical sputum samples, with Xpert MTB/RIF as the reference standard.

Main Results:

• The FLIPP-NAAT device has a low material cost ($0.88 for 12 zones) and reagent cost ($0.43 per reaction).
• The assay demonstrated high specificity for Mtb, analytical sensitivity of ~10 copies of Mtb gDNA, and tolerance to complex samples.
• Clinical evaluation showed 100% sensitivity and 68.75% specificity for sputum-based TB detection.

Conclusions:

• FLIPP-NAAT is a promising, low-cost platform technology for molecular diagnostics, particularly for TB detection in low- and middle-income countries.
• The dry-storage capability and ease of use make FLIPP-NAAT suitable for point-of-care applications without cold chain requirements.
• The modular design allows for adaptation to detect various nucleic acid sequences beyond TB.