Enzymatic Assay for Cu(II) with Horseradish Peroxidase and Its Application in Colorimetric Logic Gate

Abstract

We report an ultrasensitive and colorimetric assay for Cu(II) via enzymatic amplification strategy. The enzymatic activity of horseradish peroxidase (HRP) is strongly inhibited by Cu(I), which can be used indirectly to assay Cu(II). The limit of detection (LOD) is 0.37 nM, and the detection of 20 nM Cu(II) in solution can be achieved with naked eyes. This assay can be used to construct a colorimetric logic gate.

Colorimetric detection of Shewanella oneidensis based on immunomagnetic capture and bacterial intrinsic peroxidase activity

“…Colorimetric assays based on horseradish peroxidase/3,3′,5,5′-tetramethyl-benzidine (HRP/TMB) system have recently gained much attention due to their various advantages such as high sensitivity, low toxicity and simple management161718. HRP is a heme-containing protein that can utilize hydrogen peroxide to oxidize a wide variety of compounds.…”

Materials for Microfluidic Immunoassays: A Review

“…[17] Molecular logic gate can overcome the physical limitation of traditional silicon-based electronic system. [33] Combining the concept of logic gates with microfluidic immunoassays, a microfluidic bead-based immunoassays can perform logic operations for diagnosis (Figure 1d). [18] The microfluidic immunoassay-based logic gates use tumor necrosis factor-α (TNF-α) cytokine and its antibody as the signal inputs and different functionalized polystyrene microbeads as the logic sensors.…”

“…This is an entirely new feature of such microfluidic immunoassays. [33,18] The western blot (WB) is a widely used analytical technique in many fields ranging basic biology to medicine, and can detect specific proteins in a sample of cell/tissue homogenate or extract. We combines a microfluidic immunoassay with conventional protein blotting to develop a microfluidic western blot (µWB) (Figure 1e).…”

“…[57] Thus, there is a pressing need to develop more powerful chemical strategies in developing HRP-triggered AuNP-based immunoassay biosensors. Iodide can catalyze the oxidation of cysteine to form cystine in the presence of H 2 O 2 .…”

Selective oxidation of enzyme extracts for improved quantification of peroxidase activity

“…A variety of methods exist for the determination of peroxidase activity, including those based on colorimetric [19][20], fluorometric [21], chemiluminescent [22], and electrochemical [23] detection. Among these, colorimetric detection is most commonly used as it is simple and economical [24].…”