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Analytica Chimica Acta (v.749, #)
Silicon nanowire biosensor and its applications in disease diagnostics: A review
by Guo-Jun Zhang; Yong Ning (pp. 1-15).
A typical SiNW FET-based biosensor for detecting biomolecules.Display Omitted► SiNW biosensor has been developed as a sensitive, label-free, electrical tool. ► SiNW biosensor has been applied to the detection of important biomarkers. ► SiNW biosensor shows a potential of miniaturization and integration. ► SiNW biosensor indicates a promising POC device for disease diagnostics. ► The diseases can include cancer, cardiovascular disease, and infectious disease.Over the past decade, silicon nanowire (SiNW) biosensors have been studied for the detection of biological molecules as highly sensitive, label-free, and electrical tools. Herein we present a comprehensive review about the fabrication of SiNW biosensors and their applications in disease diagnostics. We discuss the detection of important biomarkers related to diseases including cancer, cardiovascular diseases, and infectious diseases. SiNW biosensors hold great promise to realize point-of-care (POC) devices for disease diagnostics with potential for miniaturization and integration.
Keywords: Silicon nanowire; Biosensor; Disease; Diagnostics
Carbon nanotubes as solid-phase extraction sorbents prior to atomic spectrometric determination of metal species: A review
by C. Herrero Latorre; J. Álvarez Méndez; J. Barciela García; S. García Martín; R.M. Peña Crecente (pp. 16-35).
Display Omitted► The use of CNTs as sorbent for metal species in solid phase extraction has been described. ► Physical and chemical strategies for functionalization of carbon nanotubes have been discussed. ► Published analytical methods concerning solid phase extraction and atomic spectrometric determination have been reviewed.New materials have significant impact on the development of new methods and instrumentation for chemical analysis. From the discovery of carbon nanotubes in 1991, single and multi-walled carbon nanotubes – due to their high adsorption and desorption capacities – have been employed as sorption substrates in solid-phase extraction for the preconcentration of metal species from diverse matrices. Looking for successive improvements in sensitivity and selectivity, in the past few years, carbon nanotubes have been utilized as sorbents for solid phase extraction in three different ways: like as-grown, oxidized and functionalized nanotubes. In the present paper, an overview of the recent trends in the use of carbon nanotubes for solid phase extraction of metal species in environmental, biological and food samples is presented. The determination procedures involved the adsorption of metals on the nanotube surface, their quantitative desorption and subsequent measurement by means of atomic spectrometric techniques such as flame atomic absorption spectrometry, electrothermal atomic absorption spectrometry or inductively coupled plasma atomic emission spectrometry/mass spectrometry, among others. Synthesis, purification and types of carbon nanotubes, as well as the diverse chemical and physical strategies for their functionalization are described. Based on 140 references, the performance and general properties of the applications of solid phase extraction based on carbon nanotubes for metal species atomic spectrometric determination are discussed.
Keywords: Abbreviations; 5,4-DABR; 5-(4′-dimethylamino benzyliden)-rhodanine; 8-HQ; 8-hydroxyquinoline; ABT; 2-aminobenzothiazole; APDC; ammonium pyrrolidine dithiocarbamate; CAD; catalytic arc discharge; CDTA; ciclohexanediaminetetraacetic acid; CNT; carbon nanotube; CRM; certified reference material; CTAC; cetyltrimethylammonium chloride; CV-AAS; cold vapor atomic absorption spectrometry; CV-AFS; cold vapor atomic fluorescence spectrometry; CVD; chemical vapor deposition; D2EHPA; di-(2-ethylhexyl phosphoric acid); DWCNT; double walled carbon nanotube; DZ; dithizone or 1,5-diphenylthiocarbazone; EDA; ethylenediamine; EDS; energy dispersive spectroscopy; EDTA; ethylenediamineteraacetic acid; ETAAS; electrothermal atomic absorption spectrometry; FAAS; flame atomic absorption spectrometry; FIA; flow injection analysis; FT-IR; Fourier transform-infrared spectroscopy; HG-AFS; hydride generation atomic fluorescence spectrometry; HG-DC-AFS; hydride generation double channel atomic fluorescence spectrometry; ICP; inductively coupled plasma atomic emission spectrometry; ICP–MS; inductively coupled plasma atomic emission spectrometry/mass spectrometry; ICP-OES; inductively coupled plasma optical emission spectrometry; IDA; iminodiacetic acid; LA; laser ablation; LLE; liquid–liquid extraction; LOD; limit of detection; MBT; 2-mercaptobenzothiazole; MIP; molecular imprinted polymer; MWCNT; multiwalled carbon nanotube; NBHAE; N,N′-bis(2-hydroxybenzylidene)-2,2′(aminophenylthio) ethane; NMR; nuclear magnetic resonance spectroscopy; P2AT; poly(2-aminothyophenol); PAN; (2-pyridylazo)-2-naphtol; PANI; polyaniline; PE; polyethylene; PEDOT; poly(3,4-dioxythyophene); PF; preconcentration factor; PIGT; plasma induced grafting technique; PP; polypropylene; PTFE; polytetrafluoroethylene; PZC; point zero charge; RS; Raman spectroscopy; RSD; relative standard deviation; SDBS; sodium dodecylbencene sulfonate; SDS; sodium dodecyl sulfate; SEM; scanning electron microscopy; SPE; solid phase extraction; SWCNT; single walled carbon nanotube; TAA; tris(2-aminoethyl) amine; TAR; 4-(2-thiazolylazo) resorcinol; TEM; transmission electron microscopy; TGA; thermo-gravimetric analysis; TOPO; tri-n-octyl phosphine oxide; TSC; thiosemicarbazide; TS-FF-AAS; thermospray flame atomic absorption spectrometry; XPS; X-ray photoelectron spectroscopy; XRD; X-ray diffractionCarbon nanotube; Solid phase extraction; Analytical applications; Metal species; Atomic spectrometry
Comparison of two lab-made spray chambers based on MSIS™ for simultaneous metal determination using vapor generation-inductively coupled plasma optical emission spectroscopy
by A. Fuentes-Cid; J. Villanueva-Alonso; E. Peña-Vázquez; P. Bermejo-Barrera (pp. 36-43).
Display Omitted► Two lab-made systems based on MSIS™ were evaluated to generate vapors of Ag, Au, Cd, Cu, Ni, Sn and Zn. ► The present study provides data about Au in a dual-mode sample-introduction system. ► The two systems were compared with the use of a forced outlet gas–liquid separator and conventional nebulization. ► The LODs were lower for Au, Cd and Sn using lab-made MSIS working in dual mode. ► 8-Hydroxyquinoline was used to improve volatilization, and detection was performed by ICPOES.The objective of this study is to evaluate the performance of two lab-made systems based on the Multimode Introduction System (MSIS™) and the modified MSIS™, to generate and introduce vapors of Ag, Cu, Cd, Cu, Ni, Sn, Zn, and also Au in the ICP torch. An univariate procedure was used to select the optimized working conditions (Ar flow, sample, reductant and waste flows, and reagent concentrations). Optimum conditions for working with modified MSIS were: nitric acid concentration 0.35M, 8-hydroxyquinoline concentration: 40mgL−1, sodium borohydride concentration: 1.75% (w/v)+0.4% (w/v) NaOH, argon purge flow to sweep the vapors to the torch: 1.2Lmin−1, sample flow and sodium borohydride flows: 2.3Lmin−1; waste flow: 7.7mLmin−1. For the optimum working conditions for lab-made MSIS in dual mode the concentration of 8-hydroxyquinoline was 225mgL−1, the Ar purge flow was 0.75Lmin−1, and the conventional nebulization flow was 2.3Lmin−1. The sensitivity obtained was higher using the lab-made MSIS than using the lab-made modified MSIS or a forced outlet gas–liquid separator. The limits of detection were better for Au, Cd, Sn than those obtained using conventional nebulization; the measurements were precise (RSDs≤5% in dual mode) and a good accuracy was obtained in the determination of Cd, Cu, Ni and Zn in a wastewater reference material using aqueous calibration and the lab-made MSIS in dual mode.
Keywords: Vapor generation; Inductively coupled plasma optical emission spectroscopy; Metal determination; Modified MSIS; Spray chamber; 8-Hydroxyquinoline
A new beryllium ion-selective membrane electrode based on dibenzo(perhydrotriazino)aza-14-crown-4 ether
by Vinod Kumar Gupta; Ashok Kumar Singh; Naveen Mergu (pp. 44-50).
Variation of potential with Be2+ activity for membrane sensors based on dibenzo(perhydrotriazino)aza-14-crown-4 ether.Display Omitted► It is the first report on an ion sensor using substituted aza-14-crown-4 for Be2+. ► Response time is 15s and life time is more than 4months with good reproducibility. ► The proposed electrode works well in a wide pH range 3.0–9.0.Beryllium(II) selective electrodes have been fabricated based on poly(vinyl chloride) (PVC) matrix membranes containing newly synthesized neutral carrier dibenzo(perhydrotriazino)aza-14-crown-4 ethers as ionophore. Best performance was exhibited by the membrane having a composition ionophore (IIa):PVC:sodium tetraphenylborate (NaTPB):tributyl phosphate (TBP) in the ratio (w/w; mg) of 5:30:3:65. This membrane worked well over a wide concentration range 7.6×10−6 to 1.0×10−1M of Be2+ with a Nernstian slope of 30.7mV per decade of beryllium activity. The response time of the sensor is 15s and the membrane can be used over a period of 4months with good reproducibility. The proposed electrode works well in a wide pH range 3.0–9.0. It was successfully applied to the determination of beryllium in a mineral sample.
Keywords: Beryllium selective electrode; Dibenzo(perhydrotriazino)aza-14-crown-4 ether; Poly(vinyl chloride) membrane; Potentiometry
Development of an extraction method for the determination of prostaglandins in biological tissue samples using liquid chromatography–tandem mass spectrometry: Application to gonads of Atlantic cod ( Gadus morhua)
by Steve Janagap; Rita Azeredo; Thu-Thao Nguyen; Kristin Hamre; Pedro Araujo (pp. 51-55).
Display Omitted► Novel method for extraction of prostaglandins from fish gonads using LC–MS/MS. ► Key features: low sample and solvent consumption and high sample throughput. ► The method is a better alternative to ELISA generally used in reproduction studies.A simple extraction method for the analysis of PGE2 and PGF2α in gonad samples from Atlantic cod and further quantification by using liquid chromatography–tandem mass spectrometry is proposed. The evaluation of the best solvent extraction conditions and the analytical performance parameters are reported. The method was highly selective for both prostaglandins and the calibration curves, based on the internal standard method, were linear between 5 and 1000ngmL−1 for PGE2 and PGF2α, with limits of detection of 1ngmL−1 and 1.5ngmL−1 and recovery values of 99.999±0.002 and 99.967±0.023 respectively. The homogenization of samples using liquid nitrogen combined with the developed extraction protocol can be implemented in different types of biological tissues.
Keywords: Gonads; Prostaglandins; Prostaglandin E; 2; Prostaglandin F; 2α; Liquid chromatography–tandem mass spectrometry; Atlantic cod
Polyethyleneimine-capped silver nanoclusters as a fluorescence probe for sensitive detection of hydrogen peroxide and glucose
by Ting Wen; Fei Qu; Nian Bing Li; Hong Qun Luo (pp. 56-62).
Display Omitted► A new method for synthesis of Ag nanoclusters using polyethyleneimine as a stabilizing agent was developed. ► Water-soluble Ag nanoclusters possessed high fluorescence and excellent biocompatibility. ► A new approach for determination of glucose and H2O2 by fluorescence quenching was developed. ► The method for detecting glucose and H2O2 has high sensitivity, low toxicity, and easy operation. ► Ag nanoclusters has great potential for bioimaging.In this work, we utilized polyethyleneimine-capped silver nanoclusters (PEI-Ag nanoclusters) to develop a new fluorometric method for the determination of hydrogen peroxide and glucose with high sensitivity. The PEI-Ag nanoclusters have an average size of 2nm and show a blue emission at 455nm. The photostable properties of the PEI-Ag nanoclusters were examined. The fluorescence of the PEI-Ag nanoclusters could be particularly quenched by H2O2. The oxidization of glucose by glucose oxidase coupled with the fluorescence quenching of PEI-Ag nanoclusters by H2O2 can be used to detect glucose. Under optimum conditions, the fluorescence intensity quenched linearly in the range of 500nM–100μM with high sensitivity. The detection limit for H2O2 was 400nM. And a linear correlation was established between fluorescence intensity ( F0− F) and concentration of glucose in the range of 1.0×10−6 to 1.0×10−5M and 1.0×10−5 to 1.0×10−3M with a detection limit of 8.0×10−7M. The method was used for the detection of glucose in human serum samples with satisfactory results. Furthermore, the mechanism of sensitive fluorescence quenching response of Ag nanoclusters to glucose and H2O2 has been discussed.
Keywords: Silver nanoclusters; Polyethyleneimine; Hydrogen peroxide; Glucose; Fluorescence quenching
Acid dissociation constants of uridine-5′-diphosphate compounds determined by31phosphorus nuclear magnetic resonance spectroscopy and internal pH referencing
by Igor Jancan; Megan A. Macnaughtan (pp. 63-69).
Display Omitted► The first reported phosphate and imide p Ka values of UDP-GlcNAc and UDP-S-GlcNAc. ► New role for the monosaccharide in the imide p Ka of uridine-5′-phosphate compounds. ► UDP-S-GlcNAc and UDP-GlcNAc have the same phosphate p Ka, unlike thioyl analogs. ► The31P chemical shift of inorganic phosphate is a viable internal pH reference. ► Stability of the external31P chemical shift reference is essential.The acid dissociation constant (p Ka) of small, biological molecules is an important physical property used for investigating enzyme mechanisms and inhibitor design. For phosphorus-containing molecules, the31P nuclear magnetic resonance (NMR) chemical shift is sensitive to the local chemical environment, particularly to changes in the electronic state of the molecule. Taking advantage of this property, we present a31P NMR approach that uses inorganic phosphate buffer as an internal pH reference to determine the p Ka values of the imide and second diphosphate of uridine-5′-diphosphate compounds, including the first reported values for UDP-GlcNAc and UDP-S-GlcNAc. New methods for using inorganic phosphate buffer as an internal pH reference, involving mathematical correction factors and careful control of the chemical shift reference sample, are illustrated. A comparison of the newly determined imide and diphosphate p Ka values of UDP, UDP-GlcNAc, and UDP-S-GlcNAc with other nucleotide phosphate and thio-analogs reveals the significance of the monosaccharide and sulfur position on the p Ka values.
Keywords: Abbreviations; P; i; inorganic phosphate; UDP; uridine 5′-diphosphate; UDP-GlcNAc; uridine 5′-diphosphate-; N; -acetylglucosamine; GlcNAc; N; -acetylglucosamine; UDP-S-GlcNAc; uridine 5′-diphosphate-thio-; N; -acetylglucosamine; p; K; a1; second diphosphate acid dissociation constant; p; K; a2; imide acid dissociation constant; δ; Pi; 31; P chemical shift of inorganic phosphate; δ; P; 31; P chemical shift of mono-protonated diphosphate; Δ; δ; 2; 31; P chemical shift difference between the mono-protonated diphosphate and deprotonated diphosphate; Δ; δ; 2; 31; P chemical shift difference between the deprotonated diphosphate and deprotonated imide; 2; J; αβ; 31; P–; 31; P scalar coupling constant; D; 2; O; deuterium oxide; ADP; adenosine 5′-diphosphate31; Phosphorus; Nuclear magnetic resonance; Uridine 5′-diphosphate-; N; -acetylglucosamine; Acid dissociation; pH reference; Thio-analog
Label-free and fluorescence turn-on aptasensor for protein detection via target-induced silver nanoclusters formation
by Jing-Jing Liu; Xiao-Rong Song; Yi-Wei Wang; Ai-Xian Zheng; Guo-Nan Chen; Huang-Hao Yang (pp. 70-74).
Display Omitted► A turn-on aptasensor was developed via target induced silver nanoclusters formation. ► This aptasensor exhibited high sensitivity and selectivity for PDGF-BB detection. ► This aptasensor is capable of detecting PDGF-BB in real samples. ► This aptasensor is label-free, making it more simple and cost effective.A simple turn-on and homogeneous aptasensor, which relies on target induced formation of silver nanoclusters (Ag NCs), was developed for the determination of platelet-derived growth factor B-chain homodimer (PDGF-BB). The aptasensor contains two hairpin DNA probes termed as P1 and P2. P1 consists of the aptamer sequence of PDGF-BB. Meanwhile, P2 contains the Ag NCs nucleation sequence, which is blocked by the hairpin stem region. P1 and P2 can co-exist metastably in the absence of PDGF-BB and maintain hairpin structure. However, in the presence of PDGF-BB, the binding of PDGF-BB with aptamer will result in the hybridization between P1 and P2, and release the Ag NCs nucleation sequence. In this case, Ag NCs can be formed via the reduction of Ag+ by NaBH4. By monitoring the increase in fluorescence intensity, we could detect the target protein with high sensitivity. The detection limit of this aptasensor is 0.37nM, which is comparable with that of other reported aptasensors. Furthermore, this proposed aptasensor shows high selectivity toward its target protein. Thus, the proposed aptasensor based on target induced formation of Ag NCs could be used as a sensitive and selective platform for the detection of target protein.
Keywords: Aptasensor; Label-free; Fluorescence turn-on; Silver nanoclusters; Platelet-derived growth factor B-chain homodimer
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