Pyrenyl carbon nanostructures for ultrasensitive measurements of formaldehyde in urine

Abstract

Measurement of ultra-low (e.g., parts-per-billion) levels of small-molecule markers in body fluids (e.g., serum, urine, saliva) involves a considerable challenge in view of designing assay strategies with sensitivity and selectivity. Herein we report for the first time an amperometric nano-bioelectrode design that uniquely combines 1-pyrenebutyric acid units pi-pi stacked with carboxylated multiwalled carbon nanotubes on the surface of gold screen printed electrodes for covalent attachment of NAD+ dependent formaldehyde dehydrogenase (FDH). The designed enzyme bioelectrode offered 6 ppb formaldehyde detection in 10-times diluted urine with a wide dynamic range of 10 ppb to 10 ppm. Fourier transform infrared, Raman, and electrochemical impedance spectroscopic characterizations confirmed the successful design of the FDH bioelectrode. Flow injection analysis provided lower detection limit and greater affinity for formaldehyde (apparent KM 9.6 ± 1.2 ppm) when compared with stirred solution method (apparent KM 19.9 ± 4.6 ppm). Selectivity assays revealed that the bioelectrode was selective toward formaldehyde with a moderate cross-reactivity for acetaldehyde (~ 25%) and negligible cross-reactivity toward propanaldehyde, acetone, methanol, and ethanol. Formaldehyde is an indoor pollutant, and studies have indicated neurotoxic characteristics and systemic toxic effects of this compound upon chronic and high doses of exposure. Moreover, reported chromatography and mass spectrometry methods identified elevated urine formaldehyde levels in patients with bladder cancer, dementia, and early stages of cognitive impairments compared to healthy people. Results demonstrate that pyrenyl carbon nanostructures-based FDH bioelectrode design represents novelty and simplicity for enzyme-selective electrochemical quantitation of small 30 Da formaldehyde. Broader applicability of the presented approach for other small-molecule markers is feasible that requires only the design of appropriate marker-specific enzyme systems or receptor molecules.

Carbon Nanofiber and Meldola Blue Based Electrochemical Sensor for NADH: Application to the Detection of Benzaldehyde

“…Compared to other aldehyde biosensors described in the literature , the analytical performances reported here with MB‐erGO/CNF electrodes and a novel aldehyde dehydrogenase from psychrophilic bacteria may not seem very impressive. However, a very low concentration of enzyme is used in the test, only 0.7 mU as compared for example to 130 mU for a similar disposable biosensor for acetaldehyde previously developed by some of us .…”

“…The reagentless biosensor thus obtained was able to detect benzaldehyde with a detection limit of 5 μmol L −1 in the linear range from 10 to 150 μmol L −1 . A NAD + ‐dependent formaldehyde dehydrogenase from Pseudomonas putida was immobilized on a screen‐printed electrode modified with 1‐pyrene butyric acid and MWCNTs and allowed reaching a detection limit of 6 ppb formaldehyde . Mitsubayashi et al.…”

Electrochemical diagnostics of infectious viral diseases: Trends and challenges

“…Electrochemical biosensors are categorized into amperometric ( Diba et al, 2015 ), potentiometric ( Wang et al, 2010 ), voltammetric ( Caygill et al, 2010 ) and impedimetric ( Simão et al, 2020 ) based on the method of transduction. These electrochemical biosensors have been utilized to analyze several biological agents such as proteins, nucleic acid, disease biomarkers ( Premaratne et al, 2017 ; Reddy et al, 2020 ) and several others ( Goud et al, 2017 ; GOUD et al, 2016 ; K. Yugender Goud et al, 2019 ; Kotagiri Yugender Goud et al, 2019 ; Satyanarayana et al, 2019 ; Yugender Goud et al, 2016 ). Electrochemical biosensors are claimed to be highly sensitive types of transducers by offering ultra-low-level sensitivity up to parts per trillion level or sub-pico/femto molar range with linear output, low power requirements and good resolution ( Niroula et al, 2016 ; Premaratne et al, 2018 ; Rasouli et al, 2018 ; Singh and Krishnan, 2014 ) Additionally, they provide an excellent repeatability, accuracy and ability to be miniaturized as a very tiny device form ( Kim et al, 2018 ).…”

An Electroanalytical Flexible Biosensor Based on Reduced Graphene Oxide-DNA Hybrids for the Early Detection of Human Papillomavirus-16

“…Integration of such flexible sensing electrodes with suitable nanomaterials further adds to electroanalytical properties. The high surface-to-volume ratio providing enhanced receptor immobilization and quantum confinement features resulting in superior electronic conductivity or signal amplification have proved to be a boon in the development of electrochemical biosensors [ 14 , 15 , 16 , 17 ]. Graphene-based nanomaterials have been deployed in a variety of applications due to diverse possibilities of functionalization, biocompatibility and appreciable stability under physiological conditions, henceforth making them versatile nano-transduction electrode modifiers [ 18 , 19 , 20 , 21 ].…”