A gold nanoparticle piezoelectric immunosensor using a recombinant antigen for detecting Leishmania infantum antibodies in canine serum

Abstract

Visceral leishmaniasis (VL) is a severe systemic and infectious disease potentially fatal when undiagnosed or untreated. So far, accurate diagnosis is still a problem, especially in endemic areas and in the tracking and screening of asymptomatic dogs, which are good reservoirs and main host in urban areas. Recombinant antigens based on DNA technology have provided more reliable serological diagnostics since the specificity can be achieved easier than using whole extracts. This work reports a sensitive piezeolectric immunosensor for anti-Leishamnia antibodies based on rLci2B recombinant antigens immobilized on quartz crystal electrode. The electrode surface was assembled by a nafion film recovered by gold nanoparticles (AuNPs) to promote a greater amount of rLci2B due to the increase of surface area and stability on bonds. The immunosensor distinguished the positive VL canine serum showing a good linearity (r = 0.989; p << 0.01) and a low relative error (<5%) at 1:400 to 1:1600 serum dilutions. The system based on AuNP achieved better results regarding sensitivity and reproducibility than the cysteamine-based immunosensor without AuNP (r = 0.769; p = 0.147). The results obtained show as a promising tool for diagnosis of the VL.

An ultrasensitive electrochemical immunosensor for hepatitis C antibodies based on one-step-eletrosynthetized polypyrrole–graphene nanocomposite

“…In the immunoassay tests is critical to block the non-specific binding since they can produce false-positive results, reducing the specificity. Glycine is the minor amino acid found; it has been widely used in immunosensors [ 43 – 45 ]; primarily due to the reduced molecular weight with advantaging of does not perturb the electron transfer on the sensing surface and reducing the sensitivity by steric hindering. Hence, the decrease in the anodic peak indicated the glycine present as a blocking agent (Curve V).…”

ZnO-Based Electrochemical Immunosensor to Assess Vaccine-Induced Antibody-Mediated Immunity against Wild-Type and Gamma SARS-CoV-2 Strains

“…To reduce non-specific binding, glycine solution (10 μmol L −1 ) was added; a volume of 20 μL was placed and left incubating for 30 min, and the device was again washed and dried ( Figure 1 E). Glycine was used as an agent to prevent non-specific antibody binding on the device surface and to have a low dielectric constant [ 18 , 19 , 20 , 21 ]. In previous work, we have demonstrated that the glycine coating works directly on the ZnO nanorods since it has a good affinity for carboxylic groups [ 22 ].…”

Nanoparticle-Based Immunochemical Biosensors and Assays: Recent Advances and Challenges

“…The QCM apparatus often suffers from the influence of the surrounding noise and may lack sensitivity, especially in the case of low molecular weight analytes. Thus, recent approaches propose the application of novel NPs, nanomaterials, and nanocomposites. , For instance, highly biocompatible Au NPs providing a high surface-to-volume ratio were used by Chu et al. to improve the sensor performance .…”

“…Thus, recent approaches propose the application of novel NPs, nanomaterials, and nanocomposites. 481,482 For instance, highly biocompatible Au NPs providing a high surface-to-volume ratio were used by Chu et al to improve the sensor performance. 483 The surface coverage by Au NPs increased the number of the binding sites for Ab's and, subsequently, the mass of the target analyte.…”