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1.
Diabetes Res Clin Pract ; 203: 110834, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37478978

RESUMO

BACKGROUND AND AIMS: The backlog of care in resource stretched healthcare systems requires innovative approaches to aid clinical prioritisation. Our aim was to develop an informatics tool to identify and prioritise people with diabetes who are likely to deteriorate whilst awaiting an appointment to optimise clinical outcomes and resources. MATERIALS AND METHODS: Using data from electronic health care records we identified 6 risk-factors that could be addressed in 4022 people (52% male, 30% non-Caucasian) with diabetes attending a large university hospital in London. The risk-factors were new clinical events/data occurring since their last routine clinic visit. To validate and compare data-led prioritisation tool to a traditional 'clinical approach' a sample of 450 patients were evaluated. RESULTS: Of the 4022 people, 549 (13.6%) were identified as having one or more risk events/factors. People with risk were more likely to be non-Caucasian and had greater socio-economic deprivation. Taking clinical prioritisation as the gold standard, informatics tool identified high risk patients with a sensitivity of 83% and lower risk patients with a specificity of 81%. An operational pilot pathway over 3 months using this approach demonstrated in 101 high risk people that 40% received interventions/care optimisation to prevent deterioration in health. CONCLUSION: A pragmatic data-driven method identifies people with diabetes at highest need for clinical prioritisation within restricted resources. Health informatics systems such as our can enhance care and improve operational efficiency and better healthcare delivery for people with diabetes.


Assuntos
Diabetes Mellitus , Informática Médica , Humanos , Masculino , Feminino , Diabetes Mellitus/epidemiologia , Diabetes Mellitus/terapia , Atenção à Saúde , Fatores de Risco , Londres/epidemiologia
2.
J Healthc Qual Res ; 36(3): 168-175, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33487584

RESUMO

INTRODUCTION AND OBJECTIVES: Surgical patients are at risk of hospital-acquired venous thromboembolisms (VTEs), and preventative measures such as thromboembolism deterrent stockings (TEDs) and low molecular weight heparin (LMWH) are proven to be beneficial. The National Quality Requirement in the NHS Standard Contract 2017/19 in England mandates that 95% of inpatients undergo VTE risk assessments. As hospitals transition to Electronic Patient Records (EPR), it is important to observe the impact on vital safety indicators such as VTE risk. The aim of this study is to observe the effect of implementing EPR in a tertiary centre on adherence to national guidelines, including VTE assessment rates and prophylaxis administration in surgical patients. MATERIALS AND METHODS: Using consecutive sampling, all acute surgical admissions at the hospital from 26/02/2018 to 18/03/2018 (n=154) pre-EPR and 31/10/2018 to 25/11/2018 (n=151) post-EPR were observed for VTE risk assessment, 24-h re-assessment, prophylaxis prescriptions, administration, and patient compliance. Data was compared using a two-tailed Z-test. RESULTS: Pre-EPR, 96% of patients had completed VTE assessments, which increased after EPR implementation to 97% (p=0.39). LWMH prescription rates decreased from 82% to 77% following EPR (p=0.14). Moreover, TED prescriptions decreased from 84% to 64% post-EPR (p<0.01). Administration rates of prophylaxis generally improved post-EPR. The 24-h re-assessment rate decreased from 62% to 54% of patients (p=0.08). CONCLUSION: The study demonstrated that EPR is non-inferior to paper records. Transitioning to an EPR system did not interfere with the completion of VTE risk assessments, hence did not negatively impact the ability to achieve national targets.


Assuntos
Tromboembolia Venosa , Anticoagulantes/uso terapêutico , Registros Eletrônicos de Saúde , Heparina de Baixo Peso Molecular , Humanos , Prescrições , Tromboembolia Venosa/prevenção & controle
3.
Clin Radiol ; 75(9): 712.e23-712.e31, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32507314

RESUMO

AIM: To evaluate the clinical and cost implications of using computed tomography colonography (CTC) compared to optical colonoscopy (OC) as the initial colonic investigation in patients with low-to-intermediate risk of colorectal cancer (CRC). MATERIALS AND METHODS: A non-randomised, prospective single-centre study recruited 180 participants to compare the cost implications of two clinical pathways used in the diagnosis of low-to-intermediate risk of CRC that differ in the initial diagnostic test, either CTC or OC. Costs were compared using generalised linear models (GLM) and combined with quality-adjusted life years (QALYs, based on the EQ-5D-5L) to estimate cost-effectiveness at 6 months post-recruitment. Secondary outcomes assessed access to care and patient satisfaction. RESULTS: Mean (SD, n) cost at 6 months post-recruitment per participant was £991 (£316, n=105) for the OC group and £645 (£607, n=68) for the CTC group, leading to an estimated cost difference of -£370 (95% CI: -£554, -£185, p<0.001). Assuming a £20,000 willingness-to-pay per QALY threshold, there was a 91.4% probability of CTC being cost-effective at month 6. The utilisation of CTC led to improved access to care, with a shorter mean time from referral from primary care to results (6.3 days difference, p=0.005). No differences in patient satisfaction were detected between both groups. CONCLUSION: The utilisation of CTC as the first-line investigation for patients with low-to-intermediate risk of CRC has the potential to release OC capacity, of pivotal importance for patients more likely to benefit from an invasive diagnostic approach.


Assuntos
Colonografia Tomográfica Computadorizada/estatística & dados numéricos , Neoplasias Colorretais/diagnóstico , Programas de Rastreamento/métodos , Satisfação do Paciente , Idoso , Colonografia Tomográfica Computadorizada/economia , Colonoscopia/economia , Colonoscopia/estatística & dados numéricos , Neoplasias Colorretais/economia , Análise Custo-Benefício , Feminino , Seguimentos , Humanos , Masculino , Programas de Rastreamento/economia , Pessoa de Meia-Idade , Estudos Prospectivos
4.
Lab Chip ; 20(4): 760-777, 2020 02 21.
Artigo em Inglês | MEDLINE | ID: mdl-31951241

RESUMO

A dual-modality microfluidic biosensor is fabricated using a mesoporous nanostructured cysteine-graphene hydrogel for the quantification of human cardiac myoglobin (cMb). In this device, the nanoengineered mesoporous l-cysteine-graphene (Cys-RGO) hydrogel performs the role of a dual-modality sensing electrode for the measurements conducted using differential pulse voltammetry and surface plasmon resonance (SPR) techniques. High surface reactivity, mesoporous structure and fast electron transfer combined with good reaction kinetics of the graphene hydrogel in this device indicate excellent performance for the detection of human cardiac myoglobin in serum samples. In electrochemical modality, this microfluidic chip exhibits a high sensitivity of 196.66 µA ng-1 mL cm-2 for a linear range of concentrations (0.004-1000 ng mL-1) with a low limit of detection (LOD) of 4 pg mL-1 while the SPR technique shows a LOD of 10 pg mL-1 for cMb monitoring in the range 0.01-1000 ng mL-1. The intra-assay coefficient of variation was less than 8% for standard samples and 9% for real serum samples, respectively. This Cys-RGO hydrogel-based microfluidic SPR chip allows real-time dynamic tracking of cMb molecules with a high association constant of 4.93 ± 0.2 × 105 M-1 s-1 and a dissociation constant of 1.37 ± 0.08 × 10-4 s-1, self-verification, reduced false readout, and improved detection reliability.


Assuntos
Técnicas Biossensoriais , Grafite , Humanos , Hidrogéis , Microfluídica , Reprodutibilidade dos Testes
5.
Bone Joint J ; 101-B(8): 984-994, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31362557

RESUMO

AIMS: The aim of the Scaphoid Magnetic Resonance Imaging in Trauma (SMaRT) trial was to evaluate the clinical and cost implications of using immediate MRI in the acute management of patients with a suspected fracture of the scaphoid with negative radiographs. PATIENTS AND METHODS: Patients who presented to the emergency department (ED) with a suspected fracture of the scaphoid and negative radiographs were randomized to a control group, who did not undergo further imaging in the ED, or an intervention group, who had an MRI of the wrist as an additional test during the initial ED attendance. Most participants were male (52% control, 61% intervention), with a mean age of 36.2 years (18 to 73) in the control group and 38.2 years (20 to 71) in the intervention group. The primary outcome was total cost impact at three months post-recruitment. Secondary outcomes included total costs at six months, the assessment of clinical findings, diagnostic accuracy, and the participants' self-reported level of satisfaction. Differences in cost were estimated using generalized linear models with gamma errors. RESULTS: The mean cost up to three months post-recruitment per participant was £542.40 (sd £855.20, n = 65) for the control group and £368.40 (sd £338.60, n = 67) for the intervention group, leading to an estimated cost difference of £174 (95% confidence interval (CI) -£30 to £378; p = 0.094). The cost difference per participant increased to £266 (95% CI £3.30 to £528; p = 0.047) at six months. Overall, 6.2% of participants (4/65, control group) and 10.4% of participants (7/67, intervention group) had sustained a fracture of the scaphoid (p = 0.37). In addition, 7.7% of participants (5/65, control group) and 22.4% of participants (15/67, intervention group) had other fractures diagnosed (p = 0.019). The use of MRI was associated with higher diagnostic accuracy both in the diagnosis of a fracture of the scaphoid (100.0% vs 93.8%) and of any other fracture (98.5% vs 84.6%). CONCLUSION: The use of immediate MRI in the management of participants with a suspected fracture of the scaphoid and negative radiographs led to cost savings while improving the pathway's diagnostic accuracy and patient satisfaction. Cite this article: Bone Joint J 2019;101-B:984-994.


Assuntos
Análise Custo-Benefício , Fraturas Ósseas/diagnóstico por imagem , Custos de Cuidados de Saúde/estatística & dados numéricos , Imageamento por Ressonância Magnética/economia , Osso Escafoide/lesões , Traumatismos do Punho/diagnóstico por imagem , Adolescente , Adulto , Idoso , Redução de Custos/estatística & dados numéricos , Serviço Hospitalar de Emergência , Feminino , Seguimentos , Fraturas Ósseas/economia , Humanos , Modelos Lineares , Masculino , Pessoa de Meia-Idade , Satisfação do Paciente/estatística & dados numéricos , Estudos Prospectivos , Radiografia , Osso Escafoide/diagnóstico por imagem , Reino Unido , Traumatismos do Punho/economia , Adulto Jovem
6.
Int J Tuberc Lung Dis ; 23(12): 1257-1262, 2019 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-31931908

RESUMO

SETTING: Patients with presumed multidrug-resistant tuberculosis (MDR-TB) and undergoing MDR-TB treatment from Rajasthan, India.OBJECTIVE: To compare the GenoType® MTBDRsl v.1.0 (MTBDRsl) assay capacity to detect resistance to ofloxacin, amikacin, capreomycin, kanamycin and ethambutol in Mycobacterium tuberculosis with phenotypic drug susceptibility testing (DST) using MGIT™960™ in sputum samples and isolates.DESIGN: Fifty-three smear-positive sputum samples were tested directly by MTBDRsl and 205 MDR-TB isolates were processed using MTBDRsl and DST for five drugs on MGIT960. DNA sequencing was performed in isolates with discordance in the results between the two methods for the gyrA, gyrB and rrs genes.RESULT: Sensitivity and specificity of MTBDRsl was found to be respectively 93.1% and 100% for fluoroquinoline, respectively 75-78% and 100% for aminoglycosides/cyclopeptides, respectively 70% and 92% for ethambutol and respectively 92.3% and 100% for extensively drug-resistant (XDR) TB detection. On sequencing eight discordant isolates for quinolones, mutations were seen in 12.5% of the gyrB gene and among 20 discordant isolates for aminoglycosides/cyclopeptides in the rrs gene in 15% isolates. The turnaround time was 2 days for MTBDRsl vs. 10 days for MGIT960.CONCLUSIONS: MTBDRsl can be used as an initial rapid test for detecting XDR-TB, resistance to quinolones and aminogycosides/cyclopeptides in smear-positive sputum samples.


Assuntos
Testes de Sensibilidade Microbiana , Mycobacterium tuberculosis/isolamento & purificação , Tuberculose Resistente a Múltiplos Medicamentos/diagnóstico , Antituberculosos/farmacologia , Antituberculosos/uso terapêutico , DNA Bacteriano/genética , Farmacorresistência Bacteriana Múltipla , Genótipo , Humanos , Mycobacterium tuberculosis/genética , Sensibilidade e Especificidade , Escarro/microbiologia , Tuberculose Resistente a Múltiplos Medicamentos/tratamento farmacológico , Tuberculose Resistente a Múltiplos Medicamentos/microbiologia
7.
Biosens Bioelectron ; 105: 173-181, 2018 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-29412942

RESUMO

Motivation behind the present work is to fabricate a cost effective and scalable biosensing platform for an easy and reliable detection of cancer biomarker Carcinoembryonic antigen (CEA). Here, we report the sensitive and selective detection of CEA using graphene based bio-sensing platform. Large sized (~ 2.5 × 1.0cm2), uniform, continuous, single and few layers graphene films have been grown on copper (Cu) substrate employing chemical vapor deposition (CVD) technique using hexane as a liquid precursor. Functional group has been created over Graphene/Cu substrate through π-π stacking of 1- pyrenebutanoic acid succinimidyl ester (PBSE). Further, to make the sensor specific to CEA, antibody of CEA (anti-CEA) has been covalently immobilized onto PBSE/Graphene/Cu electrode. Selective and sensitive detection of CEA is achieved by anti-CEA/PBSE/Graphene/Cu electrode through electrochemical impedance spectroscopy (EIS) measurements. Under optimal condition, the fabricated sensor shows linear response in the physiological range 1.0-25.0ngmL-1 (normal value ~ 5.0ngmL-1), revealing sensitivity 563.4Ωng-1mLcm-2 with a correlation coefficient of 0.996 and limit of detection (LOD) 0.23ngmL-1. In this way, one step electrode fabrication with high specific surface area provides a light weight, low cost, reliable and scalable novel biosensing platform for sensitive and selective detection of CEA. We believe that this bioelectrode equipped with specific recognition elements could be utilized for detection of other biomolecules too.


Assuntos
Anticorpos Imobilizados/química , Técnicas Biossensoriais/instrumentação , Antígeno Carcinoembrionário/análise , Grafite/química , Animais , Antígeno Carcinoembrionário/sangue , Bovinos , Espectroscopia Dielétrica/instrumentação , Desenho de Equipamento , Humanos , Imunoensaio/instrumentação , Limite de Detecção , Modelos Moleculares , Reprodutibilidade dos Testes , Soroalbumina Bovina/química
8.
ACS Appl Mater Interfaces ; 9(39): 33576-33588, 2017 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-28892359

RESUMO

This paper demonstrates an ultrasensitive microfluidic biochip nanoengineered with microporous manganese-reduced graphene oxide nanocomposite for detection of cardiac biomarker, namely human cardiac troponin I. In this device, the troponin sensitive microfluidic electrode consisted of a thin layer of manganese-reduced graphene oxide (Mn3O4-RGO) nanocomposite material. This nanocomposite thin layer was formed on surface of a patterned indium tin oxide substrate after modification with 3-aminopropyletriethoxysilane and was assembled with a polydimethylsiloxane-based microfluidic system. The nanoengineered microelectrode was functionalized with antibodies specific to cardiac troponin I. The uniformly distributed flower-shaped nanostructured manganese oxide (nMn3O4) onto RGO nanosheets offered large surface area for enhanced loading of antibody molecules and improved electrochemical reaction at the sensor surface. This microfluidic device showed an excellent sensitivity of log [87.58] kΩ/(ng mL-1)/cm2 for quantification of human cardiac troponin I (cTnI) molecules in a wide detection range of 0.008-20 ng/mL. This device was found to have high stability, high reproducibility, and minimal interference with other biomarkers cardiac troponin C and T, myoglobin, and B-type natriuretic peptide. These advantageous features of the Mn3O4-RGO nanocomposite, in conjunction with microfluidic integration, enabled a promising microfluidic biochip platform for point-of-care detection of cardiac troponin.


Assuntos
Microfluídica , Biomarcadores , Técnicas Biossensoriais , Grafite , Humanos , Nanocompostos , Reprodutibilidade dos Testes
9.
Biosens Bioelectron ; 81: 532-545, 2016 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-27019032

RESUMO

Mycotoxins contamination in both food and feed is inevitable. Mycotoxin toxicity in foodstuff can occur at very low concentrations necessitating early availability of sensitive and reliable methods for their detection. The present research thrust is towards the development of a user friendly biosensor for mycotoxin detection at both academic and industrial levels to replace conventional expensive chromatographic and ELISA techniques. This review critically analyzes the recent research trend towards the construction of immunosensor, aptasensor, enzymatic sensors and others for mycotoxin detection with a reference to label and label free methods, synthesis of new materials including nano dimension, and transuding techniques. Technological aspects in the development of biosensors for mycotoxin detection, current challenges and future prospects are also included to provide a overview and suggestions for future research directions.


Assuntos
Técnicas Biossensoriais/métodos , Contaminação de Alimentos/análise , Micotoxinas/análise , Ração Animal/análise , Animais , Aptâmeros de Nucleotídeos/química , Técnicas Biossensoriais/instrumentação , Desenho de Equipamento , Humanos , Imunoensaio/instrumentação , Imunoensaio/métodos , Impressão Molecular/métodos , Polímeros/química
10.
Int J Tuberc Lung Dis ; 19(12): 1536-41, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26614198

RESUMO

SETTING: High-resolution melting curve analysis (HRMA) can be used to screen for mutations in genes without the need for specific probes, with low turnaround time and high cost-effectiveness. OBJECTIVE: To detect the sensitivity and specificity of a line-probe assay (LPA) and HRMA in comparison with BACTEC™ MGIT™ 960 for the detection of rifampicin (RMP) resistance. DESIGN: A total of 219 Mycobacterium tuberculosis isolates tested by MGIT 960 for RMP susceptibility were tested with HRMA and LPA. Discordant samples were processed for sequencing of the RMP resistance-determining region (RRDR) of the rpoB gene. RESULTS: HRMA identified 93 of 103 (90.3%) isolates that were resistant and 113/116 (97.4%) that were susceptible on MGIT 960, with a sensitivity and specificity of respectively 90.3% and 97.4%. HRMA identified 117/119 (98.3%) LPA-susceptible and 94/100 (94%) resistant isolates, with 98.3% specificity and 94% sensitivity. Two isolates that were susceptible on LPA but resistant on HRMA showed silent mutations at 539 and 541 codons on sequencing, while 6 isolates that were susceptible on HRMA but resistant on LPA showed D516V (n = 4) and H526C/D (n = 2) mutations. Four isolates (3.9%) that were resistant on MGIT were susceptible on all three genotypic methods, which could be due to mutations outside the RRDR or efflux pumps. CONCLUSION: HRMA shows good potential as a rapid screening tool for the detection of drug resistance.


Assuntos
Antituberculosos/farmacologia , Farmacorresistência Bacteriana/genética , Mycobacterium tuberculosis/efeitos dos fármacos , Rifampina/farmacologia , Testes de Sensibilidade Microbiana/métodos , Mutação , Sensibilidade e Especificidade
12.
J Mater Chem B ; 3(32): 6698-6708, 2015 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-32262804

RESUMO

We present a highly sensitive and selective electrochemical sandwich immunosensor (the analyte is "sandwiched" between two antibodies) based on chitosan (CH) modified nickel oxide (NiO) nanoparticles for the detection of Vibrio cholerae (Vc). The primary monoclonal antibodies specific to Vibrio cholerae (Ab-Vc) and bovine serum albumin (BSA) were co-immobilized on a CH-NiO surface deposited onto an indium tin oxide (ITO) coated glass electrode. The specific binding of Ab-Vc towards Vc was confirmed by interaction of secondary antibodies conjugated with protein [horse radish peroxidase (HRP)], with varying concentrations of hydrogen peroxide (H2O2), via electrochemical as well as optical techniques. The CH-NiO/ITO and Ab-Vc/CH-NiO/ITO electrodes have been characterized using X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, high-resolution transmission electron microscopy and electrochemical techniques. This immunoelectrode (BSA/Ab-Vc/CH-NiO/ITO) exhibits a detection range of 20-700 ng mL-1 with a sensitivity of 0.644 µA ng mL-1 cm-2 and a low detection range of 0.108 ng mL-1 to Vc concentration. Besides this, the electrochemical response of the sandwich immunosensor (HRP-Ab-Vc/Vc/BSA/Ab-Vc/CH-NiO/ITO) towards H2O2 concentration is found to be linear in the range of 10-50 mM with excellent sensitivity (2.95 mA mM-1 cm-2).

13.
Appl Biochem Biotechnol ; 174(3): 867-8, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25138602
14.
Appl Biochem Biotechnol ; 174(3): 960-70, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24916804

RESUMO

We report results of the studies relating to the fabrication of a highly sensitive label free biosensor based on graphene oxide (GO) platform for the detection of aflatoxin B1 (AFB1) which is most toxic and predominant food toxin, using electrochemical impedance spectroscopy. The structural and optical characterization of GO/Au and anti-AFB1/GO/Au has been done by electron microscopy, Raman, X-ray diffraction (XRD), UV-vis and electrochemical impedance spectroscopy (EIS). The impedimetric sensing response of immunoelectrode as a function of AFB1 concentration reveals wider linear detection range (0.5-5 ng/ml), high sensitivity (639 Ω ng(-1) ml), improved detection limit (0.23 ng ml(-1)) and good stability (5 weeks) for the label-free detection. Association constant (k a) for antigen-antibody interaction obtained as 0.46 ng ml(-1) indicates high affinity.


Assuntos
Aflatoxina B1/isolamento & purificação , Anticorpos/química , Técnicas Biossensoriais , Grafite/química , Aflatoxina B1/imunologia , Anticorpos/imunologia , Espectroscopia Dielétrica , Análise de Alimentos , Ouro/química , Humanos , Óxidos/química , Difração de Raios X
15.
Anal Chem ; 86(3): 1710-8, 2014 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-24417267

RESUMO

We propose a label-free biosensor platform to investigate the binding kinetics using antigen-antibody interaction via electrochemical and surface plasmon resonance (SPR) techniques. The L-cysteine in situ capped cadmium sulfide (CdS; size < 7 nm) quantum dots (QDs) self-assembled on gold (Au) coated glass electrode have been covalently functionalized with apolipoprotein B-100 antibodies (AAB). This protein conjugated QDs-based electrode (AAB/CysCdS/Au) has been used to detect lipid (low density lipoprotein, LDL) biomolecules. The electrochemical impedimetric response of the AAB/CysCdS/Au biosensor shows higher sensitivity (32.8 kΩ µM(-1)/cm(2)) in the detection range, 5-120 mg/dL. Besides this, efforts have been made to investigate the kinetics of antigen-antibody interactions at the CysCdS surface. The label-free SPR response of AAB/CysCdS/Au biosensor exhibits highly specific interaction to protein (LDL) with association constant of 33.4 kM(-1) s(-1) indicating higher affinity toward LDL biomolecules and a dissociation constant of 0.896 ms(-1). The results of these studies prove the efficacy of the CysCdS-Au platform as a high throughput compact biosensing device for investigating biomolecular interactions.


Assuntos
Apolipoproteína B-100/química , Lipídeos/análise , Pontos Quânticos , Ressonância de Plasmônio de Superfície/métodos , Compostos de Cádmio/química , Cisteína/química , Espectroscopia Dielétrica , Eletrodos , Ouro/química , Cinética , Sulfetos/química
16.
Nanoscale ; 6(2): 1195-208, 2014 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-24301799

RESUMO

In this paper, we present results of the studies related to fabrication of a rare earth metal oxide based efficient biosensor using an interface based on hydrothermally prepared nanostructured thulium oxide (n-Tm2O3). A colloidal solution of prepared nanorods has been electrophoretically deposited (EPD) onto an indium-tin-oxide (ITO) glass substrate. The n-Tm2O3 nanorods are found to provide improved sensing characteristics to the electrode interface in terms of electroactive surface area, diffusion coefficient, charge transfer rate constant and electron transfer kinetics. The structural and morphological studies of n-Tm2O3 nanorods have been carried out by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectroscopic techniques. This interfacial platform has been used for fabrication of a total cholesterol biosensor by immobilizing cholesterol esterase (ChEt) and cholesterol oxidase (ChOx) onto a Tm2O3 nanostructured surface. The results of response studies of the fabricated ChEt-ChOx/n-Tm2O3/ITO bioelectrode show a broad linear range of 8-400 mg dL(-1), detection limit of 19.78 mg (dL cm(-2))(-1), and high sensitivity of 0.9245 µA (mg per dL cm(-2))(-1) with a response time of 40 s. Further, this bioelectrode has been utilized for estimation of total cholesterol with negligible interference (3%) from analytes present in human serum samples. The utilization of this n-Tm2O3 modified electrode for enzyme-based biosensor analysis offers an efficient strategy and a novel interface for application of the rare earth metal oxide materials in the field of electrochemical sensors and bioelectronic devices.


Assuntos
Colesterol Oxidase/metabolismo , Nanoestruturas/química , Esterol Esterase/metabolismo , Túlio/química , Técnicas Biossensoriais , Colesterol/sangue , Colesterol Oxidase/química , Técnicas Eletroquímicas , Eletrodos , Enzimas Imobilizadas/química , Enzimas Imobilizadas/metabolismo , Vidro/química , Humanos , Cinética , Nanotubos/química , Esterol Esterase/química , Compostos de Estanho/química
17.
J Nanosci Nanotechnol ; 13(3): 1671-8, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23755572

RESUMO

We report the application of nano crystalline tin oxide quantum dots (SnO2-QDs) for electrochemical detection of Vibrio cholerae based on DNA hybridization technique. SnO2-QDs (- 1-5 nm) have been synthesized by laser ablation technique in liquid (LAL) and electrophoretically deposited onto hydrolyzed surface of indium tin oxide (ITO) coated glass electrode. A single stranded oligonucleotide probe (23 bases) have been designed form the virulent gene sequence of V. cholerae and has been immobilized onto SnO2-QDs/ITO surface for the fabrication of ssDNA/SnO2-QDs/ITO bioelectrode and these bioelectrode have been further used for DNA hybridization (dsDNA/SnO2-QDs/ITO). The electrochemical response studies have been carried out with different concentration genomic DNA (100-500 ng/microL), which indicated that SnO2 provides an effective surface to bind with the phosphate group of DNA, thus resulting in an enhanced electron transport. The hybridized electrode exhibits linear response with regression coefficient (R) 0.974, high sensitivity 35.20 nA/ng/cm2, low detection limit (31.5 ng/microL), faster response time (3 s) and high stability of 0-120 days when stored under refrigerated conditions.


Assuntos
DNA Bacteriano/análise , Pontos Quânticos , Compostos de Estanho/química , Vibrio cholerae/isolamento & purificação , Sequência de Bases , Sondas de DNA , Microscopia de Força Atômica , Espectroscopia de Infravermelho com Transformada de Fourier , Vibrio cholerae/genética , Vibrio cholerae/patogenicidade , Virulência
18.
Anal Chim Acta ; 777: 63-71, 2013 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-23622966

RESUMO

We report results of the studies relating to the fabrication and characterization of a conducting polymer based molecularly imprinted para-nitrophenol (PNP) sensor. A water pollutant, para-nitrophenol is electrochemically imprinted with polyvinyl sulphonic acid (PVSA) doped polyaniline onto indium tin oxide (ITO) glass substrate. This PNP imprinted electrode (PNPI-PANI-PVSA/ITO) prepared via chronopotentiometric polymerization and over-oxidation is characterized by Fourier transform infra-red spectroscopy (FT-IR), UV-visible (UV-vis) spectroscopy, contact angle (CA), scanning electron microscopy (SEM), cyclic voltammetry (CV) and differential pulse voltammetry (DPV) studies. The response studies of PNPI-PANI-PVSA/ITO electrode carried out using DPV reveal a lower detection limit of 1×10(-3) mM, improved sensitivity as 1.5×10(-3) A mM(-1) and stability of 45 days. The PNPI-PANI-PVSA/ITO electrode shows good precision with relative standard deviation of 2.1% and good reproducibility with standard deviation of 3.78%.


Assuntos
Compostos de Anilina/química , Técnicas Biossensoriais/métodos , Impressão Molecular , Nitrofenóis/análise , Polivinil/química , Ácidos Sulfônicos/química , Limite de Detecção , Microscopia Eletrônica de Varredura , Estrutura Molecular , Polímeros/química , Reprodutibilidade dos Testes , Espectroscopia de Infravermelho com Transformada de Fourier
19.
Nanoscale ; 5(7): 3043-51, 2013 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-23463146

RESUMO

Reduced graphene oxide (RGO) due to its excellent electrochemical properties and large surface area, has recently aroused much interest for electrochemical biosensing application. Here, the chemically active RGO has been synthesized and deposited onto an indium tin oxide (ITO) coated glass substrate by the electrophoretic deposition technique. This novel platform has been utilized for covalent attachment of the monoclonal antibodies of aflatoxin B1 (anti-AFB1) for food toxin (AFB1) detection. The electron microscopy, X-ray diffraction, and UV-visible studies reveal successful synthesis of reduced graphene oxide while the XPS and FTIR studies suggest its carboxylic functionalized nature. The electrochemical sensing results of the anti-AFB1/RGO/ITO based immunoelectrode obtained as a function of aflatoxin concentration show high sensitivity (68 µA ng(-1) mL cm(-2)) and improved detection limit (0.12 ng mL(-1)). The association constant (ka) for antigen-antibody interaction obtained as 5 × 10(-4) ng mL(-1) indicates high affinity of antibodies toward the antigen (AFB1).


Assuntos
Aflatoxina B1/análise , Técnicas Biossensoriais , Contaminação de Alimentos/análise , Grafite/química , Óxidos/química , Aflatoxina B1/imunologia , Anticorpos Monoclonais , Reações Antígeno-Anticorpo , Eletroforese , Galvanoplastia , Humanos , Oxirredução , Análise Espectral Raman , Difração de Raios X
20.
J Phys Chem B ; 117(1): 141-52, 2013 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-23270337

RESUMO

The ultrafine monodispersed cuprous oxide (Ufm-Cu(2)O) nanoparticles have been successfully synthesized by a facile wet chemical method using poly-N-vinylpyrrolidone (PVP) as a capping agent. This colloidal solution of Ufm-Cu(2)O and chitosan (CS) is electrophoretically deposited (EPD) onto the indium tin-oxide (ITO) glass substrate. Thus synthesized nanocomposite has been characterized by X-ray powder diffraction (XRD, ∼6 nm), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Fourier transform infrared (FTIR) spectroscopic techniques. This novel biomedical nanocomposite platform has been explored to fabricate a cholesterol biosensor by immobilizing cholesterol esterase (ChEt) and cholesterol oxidase (ChOx) onto Ufm-Cu(2)O-CS/ITO electrode surface. The seed germination tests of these biomaterials (Ufm-Cu(2)O-CS nanocomposite and ChOx-ChEtUfm-CuO(2)-CS nanobiocomposite), conducted using the disc diffusion method, reveal strong activity against the common pathogens and crops, indicating biocompatibility of the nanocomposite. Under optimized conditions, the linearity between the current response and the cholesterol concentration has been obtained in the range of 10-450 mg/dL, with detection limit of 15.9 mg/dL cm(-2) and a high sensitivity of 0.895 µA/(mg/dL cm(-2)). The proposed biocompatible ChEt-ChOx/Ufm-Cu(2)O-CS/ITO bioelectrode shows fast response time (<5 s), good reproducibility, and long-term stability. This biocompatible biosensor has been used to determine the total cholesterol levels in human serum samples. Investigated antimicrobial activities of bienzyme-functionalized Ufm-Cu(2)O-CS nanocomposite are the potential platform for biomedical applications.


Assuntos
Materiais Biocompatíveis , Quitosana/química , Cobre/química , Nanocompostos , Concentração de Íons de Hidrogênio , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
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