Emphasizing laccase based amperometric biosensing as an eventual panpharmacon for rapid and effective detection of phenolic compounds

Phenols and phenolic compounds are major plant metabolites used in industries to produce pesticides, dyes, medicines, and plastics. These compounds enter water bodies, soil, and living organisms via such industrial routes. Some polyphenolic compounds like phenolic acids, flavonoids have antioxidant and organoleptic qualities, as well as preventive effects against neurodegenerative illnesses, cardiovascular disease, diabetes, and cancer. However, many of the polyphenolic compounds, such as Bisphenol A, phthalates, and dioxins also cause major environmental pollution and endocrine disruption, once the dose level becomes objectionable. The development of reliable and rapid methods for studying their dose dependency, high-impact detrimental effects, and continuous monitoring of phenol levels in humans and environmental samples is a crucial necessity of the day. Enzymatic biosensors employing phenol oxidases like tyrosinase, peroxidase and laccase, utilizing electrochemical amperometric methods are innovative methods for phenol quantification. Enzymatic biosensing, being highly sensitive and efficacious technique, is illuminated in this review article as a progressive approach for phenol quantification with special emphasis on laccase amperometric biosensors. Even more, the review article discussion is extended up to nanozymes, composites of metal organic frameworks (MOFs), and molecularly imprinted polymers (MIPs) as some emerging species for electro-chemical sensing of phenols. Applications of phenol quantification and green biosensing are also specified. A concrete summary of the innovative polyphenol detection approaches with futuristic scope indicates a triumph over some existing constraints of the phenomenological approaches providing an informative aisle to the modern researchers towards the bulk readability.

Using a disposable platform based on reduced graphene oxide, iron nanoparticles and molecularly imprinted polymer for voltammetric determination of vanillic acid in fruit peels

This work reports the development and application of a disposable electrochemical platform for vanillic acid (VA) detection using screen-printed electrode modified with reduced graphene oxide, iron nanoparticles and molecularly imprinted poly(pyrrole) film. The electrochemical platform was characterized by cyclic voltammetry, electrochemical impedance spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. Using optimized conditions, the proposed disposable platform presented linear concentration ranges of 1.0 × 10^-9 to 1.5 × 10^-7 mol/L. The limits of detection and quantification obtained for the device were 3.1 × 10^-10 and 1.0 × 10^-9 mol/L, respectively. The electrochemical platform was found to be selective for VA recognition and presented voltammetric responses with good repeatability and stability. The analytical methodology developed was applied for VA determination in banana and orange peels. The results obtained showed that the proposed electrochemical platform has a good accuracy when applied for the determination of VA.

Novel SeS2-loaded Co MOF with Au@PANI comprised electroanalytical molecularly imprinted polymer-based disposable sensor for patulin mycotoxin

An SeS₂-loaded Co MOF and Au@PANI nanocomposite comprising the base matrix of the electrode was developed with electropolymerized molecularly imprinted polymer (MIP) consisting of p-aminobenzoic acid (PABA) and patulin (PT) to detect PT molecules based on the PT imprinted cavities. SeS₂@Co MOF and Au@PANI were synthesized using hydrothermal synthesis and interfacial polymerization strategies, respectively. A suitable functional monomer to fabricate the MIP platform was selected using the density functional theory (DFT/M06-2X method). Higher electrochemical active surface area (0.985 cm² which is 6.99 times higher than the bare SPE) and a lower charge transfer resistance (R_ct = 27.8 Ω) at the MIP/Au@PANI/SeS₂@Co MOF electrode was achieved based on the higher number of adsorptive sites and enhanced conductivity (electron transfer rate constant (k_s = 3.24 × 10^-3 s^-1) of the sensing platform. The fabricated MIP sensor performance was studied in 10 mM PBS (pH = 6.4), where an improved detection limit (0.66 pM) for PT and a broad logarithmic linear dynamic range (0.001-100 nM) were both observed. The sensor possessed higher selectivity (Imprinting factor = 15.4 for PT), excellent reusability (%RSD of 10 cycles = 2.49%), high storage stability (6.7% lost after 35 days), and robust reproducibility (%RSD = 3.22%) The as-prepared MIP-based PT sensor was applied to detect PT in a real-time apple juice sample (10% diluted with PBS) with a recovery % ranging from 94.5 to 106.4%. The proposed sensor possesses great advantages in terms of cost-effectiveness, providing a simple detection strategy for long-term storage stability, and reversible cycle measurements.

Chemical binding of horseradish peroxidase enzyme with poly beta-cyclodextrin and its application as molecularly imprinted polymer for the monitoring of H2 O2 in human plasma samples

In this study, a selective and sensitive molecular imprinting-based electrochemical sensors, for horseradish peroxidase (HRP) entrapment was fabricated using electro polymerization of ß-Cyclodextrin (ß-CD) on the surface of glassy carbon electrode. Poly beta-cyclodextrin P(ß-CD) provide efficient surface area for self-immobilization of HRP as well as improve imprinting efficiency. The proposed imprinted biosensor successfully utilized for detection of HRP with excellent analytical results which linear range is 0.1 mg/mL to 10 ng/mL with LOD of 2.23 ng/mL. Furthermore, electrocatalytical activity of the prepared biosensor toward the reduction of hydrogen peroxide was investigated in the ranges of 1 to 15 μM with a detection limit of 0.4 μM by using chronoamperometry technique. The developed biosensor was used for the detection of hydrogen peroxide in unprocessed human plasma sample.

Directly assembled electrochemical sensor by combining self-supported CoN nanoarray platform grown on carbon cloth with molecularly imprinted polymers for the detection of Tylosin

Molecularly imprinted polymers (MIPs) based on electrochemical sensors (MIP-EC sensors) have obtained ideal achievements in recent years. However, some challenges are still need to be addressed, such as adjustable preparation, unstable sensing interface and great signal-to-noise ratio. Here, based on the ingenious combination of the MIP and the self-supported CoN nanowire arrays grown on carbon cloth (CoN NWs/CC), a robust MIP-EC sensor was developed, in which the MIP film was uniformly coated on the CoN NWs/CC via a bulk polymerization crosslinking process. Especially, CoN NWs/CC were prepared via in-situ transformation of their oxide precursors and then directly as a candidate of EC electrode. Under the optimal conditions, the MIP-EC sensor can detect Tylosin (TS) in the concentration range from 8.6 × 10^-11 to 6.7 × 10^-5 mol L^-1, and the low detection limit (LOD) is 5.5 × 10^-12 mol L^-1 (S/N = 3). Furthermore, the MIP-EC sensor showed high selectivity, reproducibility and stability. The practicability of the MIP-EC sensor was tested in the actual samples of surface water and soil with the comparison of the traditional ELISA method. The developed MIP-EC sensor with simple and fabrication process can provide a versatile and reliable method, which has great potential application value for the detection of small hazardous molecules.