Identification of Paracoccidioides brasiliensis by Gold Nanoprobes

Author(s)

Martins, Jaciara F. S. ; Castilho, Maiara L. ; Cardoso, Maria A. G. ; Carreiro, Andrea P. ; Martin, Airton A. ; Raniero, Leandro ; MahadevanJansen, A ; Petrich, W

• Document type: Journal article
• Source: BIOMEDICAL VIBRATIONAL SPECTROSCOPY V: ADVANCES IN RESEARCH AND INDUSTRY; v. 8219, p. 6-pg., 2012-01-01.

Abstract

Paracoccidioides brasiliensis (P. brasiliensis) is a thermal dimorphic fungus and causal agent of paracoccidioidomycosis. Epidemiological data shows that it is mainly concentrated in Central and South America countries, with most registered cases in Colombia, Brazil, and Venezuela. The histopathological similarity with others fungal infection makes the diagnosis of P. brasiliensis more complicated. Therefore, the aim of this work was to find a positive and negative test for P. brasiliensis using gold nanoprobes as a new tool for P. brasiliensis detection. Gold nanoparticles were synthesized by reduction of gold chloride with sodium citrate. The results of this procedure is a wine-red solution with a maximum absorption in the range of similar to 520-530nm. A specific P. brasiliensis sequence of oligonucleotide was bonded to the nanoparticles, which maintained the wine-red color. The color changes from red to blue for negative diagnostic and is unchanged for a positive test. The H-bond interaction of DNA with the complementary DNA keeps strands together and forms double helical structure, maintaining the colloid stability. However, for non-complimentary DNA sequence the nanoprobes merge into a cluster, changing the light absorption. (AU)

• FAPESP's process: 09/09559-5 - Gold nano-probe for Paracoccidioides brasiliensis diagnoses
• Grantee: Leandro José Raniero
• Support Opportunities: Regular Research Grants