Tween 80 Improves the Acid-Fast Bacilli Quantification in the Magnetic Nanoparticle-Based Colorimetric Biosensing Assay (NCBA).

Despite its reduced sensitivity, sputum smear microscopy (SSM) remains the main diagnostic test for detecting tuberculosis in many parts of the world. A new diagnostic technique, the magnetic nanoparticle-based colorimetric biosensing assay (NCBA) was optimized by evaluating different concentrations of glycan-functionalized magnetic nanoparticles (GMNP) and Tween 80 to improve the acid-fast bacilli (AFB) count. Comparative analysis was performed on 225 sputum smears: 30 with SSM, 107 with NCBA at different GMNP concentrations, and 88 with NCBA-Tween 80 at various concentrations and incubation times. AFB quantification was performed by adding the total number of AFB in all fields per smear and classified according to standard guidelines (scanty, 1+, 2+ and 3+). Smears by NCBA with low GMNP concentrations (≤1.5 mg/mL) showed higher AFB quantification compared to SSM. Cell enrichment of sputum samples by combining NCBA-GMNP, incubated with Tween 80 (5%) for three minutes, improved capture efficiency and increased AFB detection up to 445% over SSM. NCBA with Tween 80 offers the opportunity to improve TB diagnostics, mainly in paucibacillary cases. As this method provides biosafety with a simple and inexpensive methodology that obtains results in a short time, it might be considered as a point-of-care TB diagnostic method in regions where resources are limited.

Application of DNA sequences in anti-counterfeiting: Current progress and challenges.

Counterfeiting has never been more challenging than during the COVID-19 pandemic as counterfeit test kits and therapeutics have been discovered in the market. Current anti-counterfeiting labels have weaknesses: they can either be duplicated easily, are expensive or ill-suited for the existing complex supply chains. While RFID tags provide for an excellent alternative to current anti-counterfeiting methods, they can prove to be expensive and other routes involving nanomaterials can be difficult to encrypt. A DNA based anticounterfeiting system has significant advantages such as relative ease of synthesis and vast data storage abilities, along with great potential in encryption. Although DNA is equipped with such beneficial properties, major challenges that limit its real-world anti-counterfeiting applications include protection in harsh environments, rapid inexpensive sequence determination, and its attachment to products. This review elaborates the current progress of DNA based anti-counterfeiting systems and identifies technological gaps that need to be filled for its practical application. Progress made on addressing the primary challenges associated with the use of DNA, and potential solutions are discussed.