The comparison between label-free and non-cross-linking methods with gold nanoparticles for colorimetric detection of Paracoccidioides brasiliensis

• Published in: Research on biomedical engineering 2019-03, Vol.35 (1), p.39-44
• Main Authors: Cândido, M. A., Comparato-Filho, O. O., Oliveira, I. R., Castilho, M. L., Raniero, L.
• Format: Article
• Language: English
• Subjects: Biomaterials; Biomedical Engineering and Bioengineering; Biomedical Engineering/Biotechnology; Engineering; Original Article
• ISSN: 2446-4732; 2446-4740
• DOI: 10.1007/s42600-019-00007-0

Introduction Paracoccidioidomycosis is a systemic fungal disease caused by thermos-dimorphic fungus Paracoccidioides brasiliensis ( P. brasiliensis ). Gold nanoparticles (AuNPs) are used in diagnosis because of its versatility and biocompatibility, optical properties influenced by surface plasmon resonance, and the size and geometry. Methods The colorimetric detection of the fungus P. brasiliensis was performed by AuNPs and specific 5.8S ribosomal complementary DNA sequence probe. The label-free methodologies had a final concentration of 2.22 nM, 155.95 nM, and 433.33 μM for AuNPs, primers, and MgCl2.6H2O solution, respectively. For the non-cross-linking method, the final concentration of the thiolate oligonucleotides and MgCl2.6H2O solution were 291.54 mM and 0.39 mM, respectively. Results The Gaussian curve analyses provided Gaussian center, full width at half maximum value, and Gaussian area, which are complementary colorimetric results. The test accuracy calculated using ROC curve analyses for the label-free and non-cross-linking methods were found to be 0.994 and 0.976, respectively. The sensitivity and specificity were 92% and 98.1%, respectively for label free, and 92% and 80%, respectively, for non-cross-linking test. Conclusion The alternative methodologies can be used in colorimetric detection of fungus P. brasiliensis , which the rRNA sequence could be differentiated by alteration in their staining and confirmed by the Gaussian curve and ROC curve analyses. Graphical abstract Representations of the colorimetric tests methodologies free label (left) and non-cross-linking (right)