Enzyme-free Gold-silver Core-shell Nanozyme Immunosensor for the Detection of Haptoglobin

Abstract

Nanoparticles have been widely developed and shown to have intrinsic enzymatic ability, and are used in biosensors. Compared to biological enzymes used in biosensors, which are expensive and tedious to harvest, enzyme-mimic nanoparticles or nanozymes are both more stable and sensitive. An important area in this work is the development of a simple detection principle of immunosensor based on the one-step synthesis of silver nanoparticle seeded onto a gold core. The gold-silver core-shell nanoparticle acts as a peroxidase mimic, which enables them to oxidise 3,3',5,5'-tetramethylbenzidine (TMB) with HO, giving a colourimetric response. Herein, the analytical performance of the nanozyme is exploited to detect haptoglobin as a model analyte in a 96-well plate and measured the colourimetric product using spectrophotometer. The sensitivity of the immunosensor was as low as 100 pg mL. The viability of our immunosensor was shown to have good selectivity and satisfactory recovery in real serum samples.

Production of Biogenic Nanoparticles for the Reduction of 4-Nitrophenol and Oxidative Laccase-Like Reactions

“…Colorimetric sensors using nanoparticles in the food industry for the detection of sulfites (Qin et al, 2014) as well as their use in immunoassays (ELISA) have already been developed. As biogenic nanoparticles require no enzyme or H 2 O 2 addition, it opens up their use to a wide range of applications (Asati et al, 2009; Mohamad et al, 2018). Our results showed that the biogenic PdNPs produced by D. alaskensis G20 exhibit potential application for developing colorimetric sensors as it showed specificity for substrates depending on the pH; ABTS at low pH (pH 3), 2,6-DMP and neutral (pH 7) and TMB in a biological pH range (pH 5–7).…”

A Label-free Cardiac Troponin T Electrochemiluminescence Immunosensor Enhanced by Graphene Nanoplatelets

“…In addition, BSA as a blocking agent is well studied and widely used in developing biosensors evincing their credibility as a blocking agent. 24,25 pH dependant study of ECL system…”

Nanozyme-based sensors for detection of food biomarkers: a review

“…The previous decade has seen the development of impressive biosensors that allow for sensitive and selective detection of multiple biomarkers without extensive prerequisites. [9][10][11][12][13][14][15] Conventional diagnostic techniques like immunoassays, agglutination, polymerase chain reaction (PCR), pathogen culturing among others, involve expensive and complex equipment, as well as require trained professionals to handle the system. 16 In addition, they are costly to prepare, operate, and maintain; therefore, they are not user-friendly and not easily accessible to those in under-developed areas.…”

“…The previous decade has seen the development of impressive biosensors that allow for sensitive and selective detection of multiple biomarkers without extensive prerequisites. 9–15…”

“…21 Presently, many forms of nanozymes are available based on gold, graphene, platinum, zeolites, micelles, metalloproteins, supramolecules, and dendrimers. 8,10,22,23 These are usually inexpensive and have considerably high stability. Hence, they are an exciting option to overcome the disadvantages of natural enzymes like low stability, lowered catalytic performance under changing conditions, additional steps required for purication of the enzymes, low reusability.…”