Fig. 3.
Platinum nanozyme-mediated LFA strip to enhance signal intensity in colorimetric detection of p24 biomarker (HIV detection). (a) Platinum nanozyme – mediated LFA strip. The platinum nanocatalysts (PtNCs) immobilized onto test line oxidize CN/DAB (4-chloro-1-naphthol/3,3′-diaminobenzidine, tetrahydrochloride) substrate in the presence of H2O2 to form an insoluble black product which can be observed obviously by naked eyes, (b) comparison of dynamic linear ranges among LFA, ELISA, and PtNCs LFA, and (c) representative images of LFA strips before and after signal amplification (red box emphasizes the pre- and post-amplification for 50 and 100 pg/mL sample), corresponding to the varying p24-spiked levels in sera. The star indicates the lowest concentrations which can be recognized by naked eyes. Reproduced from Refs. [66] with permission of ACS Publications.