Designing an immunosensor for detection of Brucella abortus based on coloured silica nanoparticles

• Published in: Artificial cells, nanomedicine, and biotechnology Vol. 47; no. 1; pp. 2562 - 2568
• Main Authors: Shams, Arash, Rahimian Zarif, Bahareh, Salouti, Mojtaba, Shapouri, Reza, Mirzaii, Sako
• Format: Journal Article
• Language: English
• Published: England Taylor & Francis 01.12.2019; Taylor & Francis Ltd; Taylor & Francis Group
• Subjects: Antibodies; Brucella abortus; Brucellosis; Carbodiimide; colorimetric; Colorimetry; Immunoassay; immunosensor; Immunosensors; Nanoparticles; Polyclonal antibodies; Sandwich structures; Silica; Silicon dioxide; colorimetric; immunosensor; nanoparticles; silica
• ISSN: 2169-1401; 2169-141X
• DOI: 10.1080/21691401.2019.1626403

Brucellosis has always been a threat to the health and economics of societies. We report a new colorimetric immunoassay based on colored silica nanoparticles for detection of Brucella abortus. An immunosensor was designed based on blue-SiNPs and paramagnetic nanoparticles (PMNPs). The synthesized immunosensor was conjugated with a polyclonal antibody against B. abortus, which was activated by 1-Ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC) and N-hydroxysuccinimide (NHS) to form detection and capture probes, respectively. After adding the conjugates to the bacterial suspension, sandwich structure of PMNPs B. abortus-blue-SiNPs was formed and then separated by a magnet. The blue dye was released from the silica structure and its absorbance was measured at 670 nm with a spectrophotometer. Under optimal conditions, results showed a wide dynamic range from 1.5 × 10 3 to 1.5 × 10 8  cfu mL −1 with a detection limit of 450 cfu mL −1 . The specificity of the sensor was confirmed in comparison with 5 other bacteria. Also, during the 120-days period, the complex was stable. The results suggested that it can be used in real samples (R 2 = .9865). This designed colorimetric immunoassay strategy can be used as an alternative, user-friendly and on-site tool for the rapid detection of Brucella spp. compared to other common methods with high sensitivity and specificity in a short time.