Visual detection of Brucella in bovine biological samples using DNA-activated gold nanoparticles

Abstract

Brucellosis is a bacterial disease, which, although affecting cattle primarily, has been associated with human infections, making its detection an important challenge. The existing gold standard diagnosis relies on the culture of bacteria which is a lengthy and costly process, taking up to 45 days. New technologies based on molecular diagnosis have been proposed, either through dip-stick, immunological assays, which have limited specificity, or using nucleic acid tests, which enable to identify the pathogen, but are impractical for use in the field, where most of the reservoir cases are located. Here we demonstrate a new test based on hybridization assays with metal nanoparticles, which, upon detection of a specific pathogen-derived DNA sequence, yield a visual colour change. We characterise the components used in the assay with a range of analytical techniques and show sensitivities down to 1000 cfu/ml for the detection of Brucella. Finally, we demonstrate that the assay works in a range of bovine samples including semen, milk and urine, opening up the potential for its use in the field, in low-resource settings.

Recent progress and challenges on the bioassay of pathogenic bacteria

“…This test is possible for a number of specimens from sheep including semen, milk and urine. This test can be done within 30 min 47 . Similar reports 48‐50 based on immunosensing and genosensing using EC, SPR, and so on, were reported for detection of this pathogen whis were summarized in Table 2.…”

“…Between 10 identified Brucella species, four classic species Brucella suis ( B. suis ) , Brucella canis ( B. canis ) , Brucella abortus ( B. abortus ) , and Brucella melitensis ( B. melitensis ) cause the human infections 47 . There is some of biosensors for the detection of Brucella based on optical and EC methods.…”

“…For complete of discussion, Table 2 25‐206 summarized all of the discussed articles on the detection of bacterial. It is important to point out that, there is other reports in this research area …”

Design of a gold nanoprobe for the detection ofPseudomonas aeruginosaelastase gene (lasB)

“…21,[23][24][25] In the NCL colorimetric assay, attaching the complementary portion of the target molecule to the nanoprobe makes the nanoprobes resistant to salt-induced aggregation. 21,26 It has high sensitivity and specicity, is less expensive than conventional methods and does not require much expertise. 27 As a result of light colliding with gold nanoparticles, the conduction electrons of gold oscillate collectively and reect light at different wavelengths from that of the light received; this optical phenomenon is called surface plasmon resonance.…”

Detection of Brucella abortus by a platform functionalized with protein A and specific antibodies IgG

“…bacteria is critical. Novel methodologies for Brucella detection and identification are still limited since most methods detect the bacteria indirectly using label-dependent biosensors (Fu-Chun, De-Si, Zhong, Shu-Zhen, & Ya-Fei, 2007;Liebes, Amir, Marks, & Banai, 2009;Wu et al, 2013) or sensors that require sample pretreatment (Pal et al, 2017;Rahi, Sattarahmady, & Heli, 2016). Sensitivity of the immunoassays depends on the immobilization of the antibody on a solid support of sufficient surface density in an orientation that maximizes their antigen capture capability (Holford, Davis, & Higson, 2012;Moina & Ybarra, 2012).…”