Xianbo Lu

Bisphenols (BPs), which have more than ten kinds of structural analogues, are emerging as the most important endocrine disrupting chemicals that adversely affect human health and aquatic life. A tyrosinase nanosensor based on metal–organic frameworks (MOFs) and chitosan was developed to investigate the electrochemical response characteristics and mechanisms of nine kinds of BPs for the first time. The developed tyrosinase nanosensor showed a sensitive response to bisphenol A, bisphenol F, bisphenol E, bisphenol B, and bisphenol Z, and the responsive sensitivities were highly dependent on their respective log Kow values. However, the nanosensor showed no response to bisphenol S (BPS), bisphenol AP (BPAP), bisphenol AF (BPAF), or tetrabromobisphenol A, although BPS, BPAP, and BPAF have structures similar to those of the responsive BPs. The obtained results reveal that the electrochemical response of different BPs is affected not only by the molecular structure, especially the available ortho positions of phenolic hydroxyl groups, but also by the substituent group properties (electron acceptor or electron donor) on the bisphenol framework. The electronic cloud distribution of the phenolic hydroxyl groups, which is affected by the substituent group, determines whether the available ortho positions of phenolic hydroxyl groups can be oxidized by the tyrosinase biosensor. These response mechanisms are very significant as they can be used for predicting the response characteristics of many BPs and their various derivatives and metabolites on biosensors. The unexpected anti-interference ability of the biosensor to nine heavy metal ions was also discovered and discussed. The MOF-chitosan nanocomposite proves to be a promising sensing platform for the construction of diverse biosensors for selective detection of targets even in the presence of a high concentration of heavy metal ions.

An electrochemical deoxyribonucleic acid biosensor for rapid genotoxicity screening of chemicals

Co-reporter:Lidong Wu, Xianbo Lu, Xue Wang, Yi Song and Jiping Chen

Analytical Methods 2015 vol. 7(Issue 8) pp:3347-3352

Publication Date(Web):02 Feb 2015

DOI:10.1039/C5AY00020C

A sensitive electrochemical biosensor based on double-stranded deoxyribonucleic acid (DNA) has been proposed for rapid screening of chemicals genotoxicity potential. A DNA probe from the clone RP3-402G11 gene of the human DNA sequence and electroactive methylene blue (MB) have been used as a biorecognition element and signal amplification molecules respectively for evaluating the genotoxic potential of target analytes with high sensitivity. The biosensing mechanism of genotoxicity screening is based on the damage of targets for the DNA double helix, which results in the subsequent distinct change of the electrochemical signal. More than 10 kinds of genotoxic chemicals have been used as testing analytes including highly toxic dioxins (polychlorinated dibenzodioxins, polychlorinated dibenzofurans) and polychlorinated biphenyls (PCBs). Dioxins and dioxin-like chemicals have been identified as highly genotoxic chemicals by the proposed DNA biosensor, which is consistent with the conclusion from International Agency for Research on Cancer. The results obtained demonstrated that the signal response of the biosensor for dioxins and PCBs correlated well with their toxic equivalent factor (TEF) values and concentrations of tested targets. The biosensor proved to be a promising in vitro screening tool for rapid estimation of chemicals genotoxicity potential.

3D metal-organic framework as highly efficient biosensing platform for ultrasensitive and rapid detection of bisphenol A

Co-reporter:Xue Wang, Xianbo Lu, Lidong Wu, Jiping Chen

Biosensors and Bioelectronics 2015 Volume 65() pp:295-301

Publication Date(Web):15 March 2015

DOI:10.1016/j.bios.2014.10.010

•Cu-MOF was synthesized and explored to construct a tyrosinase biosensor.•The Cu-MOF possesses >1000 m2 g−1 surface area and 3D interconnected channels.•The biosensor displayed ultrasensitive, rapid and selective response for Bisphenol A.•The biosensor method was successfully applied to determine BPA in plastic products.•MOFs-based 3D structures show great prospect as a robust biosensing platform.As is well known, bisphenol A (BPA), usually exists in daily plastic products, is one of the most important endocrine disrupting chemicals. In this work, copper-centered metal-organic framework (Cu-MOF) was synthesized, which was characterized by SEM, TEM, XRD, FTIR and electrochemical method. The resultant Cu-MOF was explored as a robust electrochemical biosensing platform by choosing tyrosinase (Tyr) as a model enzyme for ultrasensitive and rapid detection of BPA. The Cu-MOF provided a 3D structure with a large specific surface area, which was beneficial for enzyme and BPA absorption, and thus improved the sensitivity of the biosensor. Furthermore, Cu-MOF as a novel sorbent could increase the available BPA concentration to react with tyrosinase through π–π stacking interactions between BPA and Cu-MOF. The Tyr biosensor exhibited a high sensitivity of 0.2242 A M−1 for BPA, a wide linear range from 5.0×10−8 to 3.0×10−6 mol l−1, and a low detection limit of 13 nmol l−1. The response time for detection of BPA is less than 11 s. The proposed method was successfully applied to rapid and selective detection of BPA in plastic products with satisfactory results. The recoveries are in the range of 94.0–101.6% for practical applications. With those remarkable advantages, MOFs-based 3D structures show great prospect as robust biosensing platform for ultrasensitive and rapid detection of BPA.

Direct Electrochemical Tyrosinase Biosensor based on Mesoporous Carbon and Co3O4 Nanorods for the Rapid Detection of Phenolic Pollutants

Co-reporter:Xue Wang; Xianbo Lu;Dr. Lidong Wu; Jiping Chen

ChemElectroChem 2014 Volume 1( Issue 4) pp:808-816

Publication Date(Web):

DOI:10.1002/celc.201300208

Abstract

A novel tyrosinase (Tyr) biosensor based on a graphitized ordered mesoporous carbon/cobaltosic oxide nanorod (GMC/Co₃O₄) nanocomposite is developed for the rapid detection of phenolic pollutants. By applying the GMC/Co₃O₄ nanocomposite as an enzyme immobilization matrix, rapid direct electron transfer between Tyr and the electrode is achieved. The biosensor exhibits a wide linear response for catechol, ranging from 5.0×10⁻⁸ to 1.3×10⁻⁵ M, with a limit of detection down to 25 nM and a response time of less than 2 s. The sensitivity of the biosensor based on the GMC/Co₃O₄ nanocomposite (6.4 A M⁻¹ cm⁻²) is higher than that of the biosensor based on GMC (5.0 A M⁻¹ cm⁻²) or Co₃O₄ (3.5 A M⁻¹ cm⁻²), which can be attributed to the synergistic effect of the GMC/Co₃O₄ nanocomposite. The biosensor is further used to systematically detect mixed phenolic samples (phenol, catechol, m-cresol, p-cresol, and 4-chlorophenol) and real water samples. The biosensor-based detection results for river water and tap water samples show outstanding average recovery (92.2–103.3 %) and relative standard deviations (0.9–7.8 %). In comparison with the conventional spectrophotometric method, the biosensor method is more rapid, sensitive, accurate, and convenient. Furthermore, the detection limit of the biosensor method is about 20 times lower than that of the spectrophotometric method. This novel biosensor is proven to be a promising alternative tool for the rapid and on-site monitoring of environmental phenolic pollutants.

Electrochemical biosensing platform based on amino acid ionic liquid functionalized graphene for ultrasensitive biosensing applications

Co-reporter:Xianbo Lu, Xue Wang, Jing Jin, Qing Zhang, Jiping Chen

Biosensors and Bioelectronics 2014 Volume 62() pp:134-139

Publication Date(Web):15 December 2014

DOI:10.1016/j.bios.2014.06.036

•A non-covalent method was developed for preparing water-soluble graphene.•Results confirmed the water-soluble graphene retained excellent electronic conductivity.•The graphene dispersions enable the use of conventional solution-phase processing techniques.•A robust biosensing platform was developed based on amino acid ionic liquid functionalized graphene.•The biosensing platform displayed excellent performance for biosensor application.In this study, a facile non-covalent method was developed for preparing water-soluble graphene with excellent electronic conductivity. Room temperature ionic liquids (ILs) with high ionic conductivity were used for the non-covalent surface functionalization of graphene through π–π stacking interactions. Compared to other ILs used, amino acid ionic liquids (AAILs) were found to be the most effective for improving the dispersion of graphene in water phase. Electrochemical and spectroscopic results confirmed that the obtained AAIL functionalized GR can retain the excellent electronic conductivity of pristine graphene without damaging the graphene lattice. The obtained water-soluble graphene (GR-AAIL) was exemplified to fabricate an electrochemical biosensor using tyrosinase as a model enzyme, and the sensitivity (12,600 mA cm−2 M−1) of GR-AAIL based biosensor was about 17 times higher than that of graphene oxide and other nanomaterial based biosensor, displaying its unprecedented high sensitivity for biosensing. The detection limit for catechol (one important environmental pollutant) reached as low as 8 nM with a response time of 3 s and a linear range from 25 nM to 11,100 nM. The AAIL-GR based biosensor also demonstrated good reproducibility, repeatability, selectivity, long-term stability and high recovery for catechol detection. Amino acid ionic liquid functionalized graphene proves to be a robust and versatile electrochemical biosensing platform for fabricating biosensors with excellent performance.

Amino Acid Ionic Liquid Modified Mesoporous Carbon: A Tailor-made Nanostructure Biosensing Platform

Co-reporter:Lidong Wu;Haijun Zhang ;Jiping Chen

ChemSusChem 2012 Volume 5( Issue 10) pp:1918-1925

Publication Date(Web):

DOI:10.1002/cssc.201200274

Abstract

A novel nanocomposite based on ordered graphitized mesoporous carbon (GMC) and amino acid ionic liquids (AAIL) is obtained through controlled surface modification of GMC with hydrophilic AAILs (1-ethyl-3-methylimidazolium alanine, EMIM[Ala]), which is used as a platform for a tyrosinase biosensor to detect phenol. The GMC–AAIL nanocomposite possesses a better biocompatibility and improved aqueous-phase dispersion than hydrophobic GMC alone, owing to the introduction of hydrophilic and biocompatible AAILs. Comparative studies revealed that the catalytic activity of tyrosinase for phenol in phosphate buffer solution (PBS) containing EMIM[Ala] was about ten times higher than that in pure PBS. By entrapping tyrosinase molecules into the mesopores of GMC, making use of the synergy effect of GMC and AAIL (the “interspace confinement effect”, the anti-fouling ability, and the biocompatible microenvironment), the GMC–AAIL-based biosensors display superior analytical performance to GMC-based ones in terms of signal-to-noise ratio, stability, repeatability, and working life. After 21-day storage, the electrode retained more than 90% of its initial response, indicating that surface modification of GMC with hydrophilic and biocompatible AAILs could significantly prolong the life of tyrosinase in vitro. The GMC10–EMIM[Ala]-based biosensor demonstrates a linear response for phenol concentrations from 0.1 to 10 µmol L⁻¹ with a low detection limit of 20 nmol L⁻¹ and sensitivity of 1385 mA cm⁻² M⁻¹. The GMC–AAIL nanocomposite proves to be a promising platform for enzyme-based biosensors and biocatalysis.

Nanographene-based tyrosinase biosensor for rapid detection of bisphenol A

Co-reporter:Lidong Wu, Dehui Deng, Jing Jin, Xianbo Lu, Jiping Chen

Biosensors and Bioelectronics 2012 Volume 35(Issue 1) pp:193-199

Publication Date(Web):15 May 2012

DOI:10.1016/j.bios.2012.02.045

Hydrophilic nanographene (NGP) prepared by ball milling of graphite was used as the support to construct a novel tyrosinase biosensor for determination of bisphenol A (BPA). The performances of the nanographene-based tyrosinase biosensor were systematically compared with those of multiwall carbon nanotubes (MWNTs) modified tyrosinase biosensors. The results indicated that the nanographene-based tyrosinase biosensor provided significant advantages over MWNTs-based tyrosinase biosensor in term of response, repeatability, background current and limit of detection (LOD), which could be attributed to its larger specific surface area and unique hierarchical tyrosinase-NGP nanostructures. The nanographene-based tyrosinase biosensor displayed superior analytical performance over a linear range from 100 nmol L−1 to 2000 nmol L−1, with LOD of 33 nmol L−1 and sensitivity of 3108.4 mA cm−2 M−1. The biosensor was further used for detecting BPA (leaching from different vessels) in tap water, and the accuracy of the results was validated by high performance liquid chromatography (HPLC). The nanographene-based tyrosinase biosensor proved to be a promising and reliable tool for rapid detection of BPA leached from polycarbonate plastic products and for on-site rapid analysis of emergency pollution affairs of BPA.Highlights► Hydrophilic nanographene was prepared in a controllable nanometer size by a simple ball milling method of graphite materials. ► The nanographene was explored to construct a novel tyrosinase biosensor for rapid, sensitive and selective determination of bisphenol A. ► Comparative studies revealed the significant advantages of nanographene over MWNTs in the performance of fabricated tyrosinase biosensors. ► The biosensor was used for detecting BPA in water samples, and the obtained results were validated by high performance liquid chromatography. ► The nanographene based tyrosinase biosensor proved to be a promising and reliable tool for rapid detection of BPA.