Picomolar-Level Melamine Detection via ATP Regulated CeO2 Nanorods Tunable Peroxidase-Like Nanozyme-Activity-Based Colorimetric Sensor: Logic Gate Implementation and Real Sample Analysis

Abstract

The capability of functional logic operations is highly intriguing, but far from being realized owing to limited recognition element (RE) and complex readout signals, which limit their applications. In this contribution, for a visual colorimetric sensor for melamine (MEL) we described the construction of two- and three-input AND logic gate by exploiting the intrinsic peroxidase (POD)-like activity of CeO2 nanorods (NRs) (~23.04% Ce3+ fraction and aspect ratio (RTEM) of 3.85 ± 0.18) as RE at acidic pH (4.5). Further ATP piloted catalytic tuning of POD-like activity in CeO2 NRs employed for a functional logic gate-controlled MEL sensing at neutral pH (7.4). AND logic circuit operated MEL sensing record colorimetric response time of 15 minutes to produce blue color proportionate to MEL concentration. The fabricated nanozyme (CeO2)-based logic gate sensor probe for MEL at pH 4.5 showed a linear response from 0.004 nM to 1.56 nM with a limit of detection (LOD) of 4 pM; while translation from acidic to neutral pH (at 7.4) sensor exhibited linear response ranging from 0.2 nM to 3.12 nM with a LOD value of 17 pM. Through CeO2 POD-like nanozyme behavior under acidic and neutral pH, the fabricated logic gate sensor showed high affinity for MEL, generating prominent visual output with picomolar sensitivity, good reproducibility, and stability with relative standard deviation (RSD) <1% and 2%, respectively. A feasibility study in real samples (raw milk and milk powder) showed good recoveries with negligible matrix effect, an anti-interference experiment revealed sensor selectivity, highlighting robust sensor practical utility. With the merits of high sensitivity, specificity, low cost, and simplified sample processing, the developed logic-controlled colorimetric MEL sensing platform with appropriate modifications can be recognized as a potent methodology for on-site analysis of various food adulterants and related applications.

Recent advances in colorimetric sensors based on nanozymes with peroxidase-like activity

“…102 Chishti B. et al successfully integrated two and a three-input regulated AND logic circuit, and established a visual colorimetric sensor for the detection of mela-mine at acidic (4.5) and neutral (7.4) pH. 103 The constructed logic gate sensor based on the intrinsic peroxidase-like activity of CeO 2 NRs displayed a high affinity for melamine, producing outstanding visual output on a logic platform of TMB/H 2 O 2 (Fig. 7).…”

“…Fig.7Schematic illustration of the logic operation mechanism for melamine detection based on peroxidase-like activity of CeO 2 NRs at acidic (4.5) and neutral (7.4) pH 103. …”

Two-step aggregation of gold nanoparticles based on charge neutralization for detection of melamine by colorimetric and surface-enhanced Raman spectroscopy platform

“…For this reason, it is imperative to reliably trace the safety issues of MEL hazardous material in food. In the last decade, various colorimetric methods have been used to detect MEL (Hu et al, 2018;Jin et al, 2018;Rajar et al, 2018;Wang et al, 2018;Chishti et al, 2021). These methods were sensitive, but the process of detection or preparation of sensors was tedious.…”

Engineering the Stability of Nanozyme-Catalyzed Product for Colorimetric Logic Gate Operations

“…Over the past few decades, a variety of functional nanomaterials with intrinsic enzyme mimetic activities have been explored, owing to the high stability, low cost, convenient storage, and easy synthesis [1][2][3][4][5][6][7][8]. One of the extensive applications and promising developments for nanozymes is in the biocomputing system, which makes noteworthy progress in the logic gate operations that follow the laws of Boolean algebra [9][10][11][12][13][14]. Recently, Boolean algebra has been widely used in the fields of engineering technology and occupies an irreplaceable position.…”