1
|
1053 Sleep Duration And Timing Associated With History Of Breast Prostate And Skin Cancer: Data From A Nationally-representative Sample. Sleep 2020. [DOI: 10.1093/sleep/zsaa056.1049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Introduction
Sleep disturbances are a common problem among cancer survivors. Also, cancer patients can have altered circadian rhythms and these changes can continue to affect the patient long after the conclusion of their treatment. This analysis aims to investigate how the sleep and wake times of cancer survivors differ from the rest of the population, depending on the type of cancer.
Methods
Data from the 2015-2016 National Health and Nutrition Examination Survey were used. Population-weighted data on N=5,581 individuals provided complete data. History of breast, prostate, and skin cancer (melanoma or other) was self-reported. Sleep duration was self-reported in half-hour increments, and typical bedtime and waketime was self-reported. Covariates included age, sex, and race/ethnicity. Weighted linear regressions with sleep duration, bedtime and waketime were examined, with each cancer type as predictor.
Results
Prevalence was 1.7% for prostate cancer, 1.5% for breast cancer, 2.3% for non-melanoma skin cancer, and 0.8% for melanoma. In adjusted analyses, prostate cancer was associated with an additional 26.5 minutes of average total sleep (95%CI 2.2,50.9, p=0.03), a 23.1 bedtime minutes earlier (95%CI -40.4,-5.8, p=0.009), and no difference in waketime. Breast cancer was associated with a bedtime that was 41.1 minutes later (95%CI 10.3,72.0, p=0.009) and a waketime that was 48.7 minutes later (95%CI 12.5,84.9, p=0.008), but no difference in sleep duration. No statistically significant effects were seen for either type of skin cancer, melanoma or non-melanoma.
Conclusion
Prostate cancer was associated with an earlier bedtime and associated increased sleep time. Breast cancer, on the other hand, was associated with a phase delay of the sleep period but no change in sleep duration. Skin cancer was not associated with differences in sleep duration or timing. These findings may have implications for not only treatment of sleep problems in different types of cancer, but also possible circadian mechanisms.
Support
Dr. Grandner is supported by R01MD011600
Collapse
|
2
|
Monitoring photosynthetic microorganism activity with an electrolyte-gated organic field effect transistor. Biosens Bioelectron 2020; 157:112166. [PMID: 32250936 DOI: 10.1016/j.bios.2020.112166] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 03/10/2020] [Accepted: 03/20/2020] [Indexed: 01/16/2023]
Abstract
Among organic thin film transistors (OTFTs), Organic Electrochemical Transistors (OECTs) have been extensively used for cell monitoring while Electrolyte-Gated Organic Field-Effect Transistors (EGOFETs) have never been described for that kind of application. However, EGOFETs are well adapted for this use because, as well as OECTs, they can operate directly in aqueous solutions such as cells culture media, but they offer much a higher on/off ratio which could lead to better sensitivity. As a proof of concept, we propose herein to monitor the photosynthetic activity of a cyanobacterium (Anabaena flos-aquae) contained within an EGOFET's electrolyte.
Collapse
|
3
|
Peptide-modified electrolyte-gated organic field effect transistor. Application to Cu2+ detection. Biosens Bioelectron 2019; 127:118-125. [DOI: 10.1016/j.bios.2018.12.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 12/05/2018] [Accepted: 12/06/2018] [Indexed: 01/13/2023]
|
4
|
The need for better access to pain treatment: learning from drug consumption trends in the USA. FUNCTIONAL NEUROLOGY 2018; 22:229-230. [PMID: 29306360 DOI: 10.11138/fneur/2017.32.4.229] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The Authors of this letter look at consumption of opioids and a2- ligands, also known as "gabapentinoids", in Italy, and specifically in the Provincial Health District of Cosenza, as compared with USA trends of recent decades. Access to analgesic drugs since the introduction of Italian law 38/2010 is also evaluated and possible future measures for better management of chronic pain are proposed.
Collapse
|
5
|
Triggering the Electrolyte-Gated Organic Field-Effect Transistor output characteristics through gate functionalization using diazonium chemistry: Application to biodetection of 2,4-dichlorophenoxyacetic acid. Biosens Bioelectron 2018; 113:32-38. [DOI: 10.1016/j.bios.2018.04.051] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 04/17/2018] [Accepted: 04/24/2018] [Indexed: 01/20/2023]
|
6
|
Enzyme-less electrochemical displacement heterogeneous immunosensor for diclofenac detection. Biosens Bioelectron 2017; 97:246-252. [DOI: 10.1016/j.bios.2017.06.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 05/30/2017] [Accepted: 06/01/2017] [Indexed: 10/19/2022]
|
7
|
|
8
|
One-step Electrosynthesis of Poly(1,5-diaminonaphthalene)/Graphene Nanocomposite as Platform for Lead Detection in Water. ELECTROANAL 2016. [DOI: 10.1002/elan.201501075] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
|
9
|
Grafting of a peptide probe for Prostate-Specific Antigen detection using diazonium electroreduction and click chemistry. Biosens Bioelectron 2016; 81:131-137. [PMID: 26938492 DOI: 10.1016/j.bios.2016.02.060] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Accepted: 02/23/2016] [Indexed: 11/28/2022]
Abstract
The main objective of this work was to validate a label-free electrochemical method of protein detection using peptides as capture probes. As a proof-of-concept, we used a 7 amino acids sequence (HSSKLQL) specific for Prostate Specific Antigen. We investigated various electrografting conditions of two anilines (2-[(4-aminophenyl)sulfanyl]-8-hydroxy-1,4-naphthoquinone and 4-azidoaniline) further converted in situ into their corresponding diazonium salts on glassy carbon electrodes. It was demonstrated that the best method to obtain a mixed layer is the simultaneous electroreduction of the two diazonium salts. 4-azidoaniline was used to covalently immobilize the ethynyl-functionalized peptide probe by click coupling, and the hydroxynaphthoquinone derivative plays the role of electrochemical transducer of the peptide-protein recognition. The proteolytic activity of PSA towards a small peptide substrate carrying streptavidin at its distal end was also investigated to design an original sensing architecture leading to a reagentless, label free, and "signal-on" PSA sensor. Without optimization, the limit of quantification can be estimated in the nM to pM range.
Collapse
|
10
|
General approach for electrochemical detection of persistent pharmaceutical micropollutants: Application to acetaminophen. Biosens Bioelectron 2015; 72:205-10. [DOI: 10.1016/j.bios.2015.05.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Revised: 05/02/2015] [Accepted: 05/05/2015] [Indexed: 11/17/2022]
|
11
|
Label-free electrochemical detection of prostate-specific antigen based on nucleic acid aptamer. Biosens Bioelectron 2014; 68:49-54. [PMID: 25569871 DOI: 10.1016/j.bios.2014.12.033] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Revised: 12/01/2014] [Accepted: 12/15/2014] [Indexed: 12/17/2022]
Abstract
We report a label-free aptasensor to make direct detection of prostate specific antigen (PSA, a biomarker of prostate cancer) using a quinone-containing conducting copolymer acting as redox transducer and grafting matrix for immobilization of the short aptamer strands. It is shown that capture of PSA generates a current decrease (signal-off) measured by Square Wave Voltammetry. This current decrease is specific for PSA above a limit of quantification in the ng mL(-1) range. The change in current is used to determine the PSA-aptamer dissociation constant K(D), of ca. 2.6 nM. To consolidate the proof of concept, a heterogeneous competitive exchange with a complementary DNA strand which breaks PSA-aptamer interactions is studied. This double-check followed by a current increase provides full assurance of a perfectly specific recognition.
Collapse
|
12
|
An electrochemical ELISA-like immunosensor for miRNAs detection based on screen-printed gold electrodes modified with reduced graphene oxide and carbon nanotubes. Biosens Bioelectron 2014; 62:25-30. [PMID: 24973539 DOI: 10.1016/j.bios.2014.06.014] [Citation(s) in RCA: 96] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Revised: 06/06/2014] [Accepted: 06/10/2014] [Indexed: 11/17/2022]
Abstract
We design an electrochemical immunosensor for miRNA detection, based on screen-printed gold electrodes modified with reduced graphene oxide and carbon nanotubes. An original immunological approach is followed, using antibodies directed to DNA.RNA hybrids. An electrochemical ELISA-like amplification strategy was set up using a secondary antibody conjugated to horseradish peroxidase (HRP). Hydroquinone is oxidized into benzoquinone by the HRP/H2O2 catalytic system. In turn, benzoquinone is electroreduced into hydroquinone at the electrode. The catalytic reduction current is related to HRP amount immobilized on the surface, which itself is related to miRNA.DNA surface density on the electrode. This architecture, compared to classical optical detection, lowers the detection limit down to 10 fM. Two miRNAs were studied: miR-141 (a prostate biomarker) and miR-29b-1 (a lung cancer biomarker).
Collapse
|
13
|
Direct, reagentless electrochemical detection of the BIR3 domain of X-linked inhibitor of apoptosis protein using a peptide-based conducting polymer sensor. Biosens Bioelectron 2014; 61:57-62. [PMID: 24858673 DOI: 10.1016/j.bios.2014.04.047] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Revised: 04/09/2014] [Accepted: 04/23/2014] [Indexed: 10/25/2022]
Abstract
In this work, we report a reagentless electrochemical peptide (AVPFAQKG) sensor to directly detect the BIR3 domain of X-linked inhibitor of apoptosis protein (XIAP-BIR3). The bioreceptor was based on a conducting copolymer film electrosynthesized from juglone and a juglone-peptide conjugate (JP) newly designed. The peptide-protein interactions generated an important increase of steric hindrance at the interface and a current decrease (signal off) of the redox reaction from quinone embedded in the polymer backbone as evidenced by Square Wave Voltammetry. This allowed a specific and sensitive detection of XIAP-BIR3 with a detection limit of 1 nM (13 ng mL(-1)). The peptide-protein complex could be then dissociated by adding the free precursor peptide (AVPFAQKG) into solution, causing a shift-back on the signal, i.e. an increase in the current intensity (signal-on). This "off-on" detection sequence was used in this work as a double verification of the specificity and this approach can be employed as a general way to increase the reliability of the results. In general, the approach described in this work may be inspired to develop other direct and reagentless electrochemical protein assays with high specificity and sensitivity.
Collapse
|
14
|
PS-028 Monitoring the appropriate use of antipsychotics in adolescents in the health district of Cosenza (Italy). Eur J Hosp Pharm 2014. [DOI: 10.1136/ejhpharm-2013-000436.379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
|
15
|
Design of interpenetrated network MWCNT/poly(1,5-DAN) on interdigital electrode: Toward NO2 gas sensing. Talanta 2013; 115:713-7. [DOI: 10.1016/j.talanta.2013.06.025] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Revised: 06/08/2013] [Accepted: 06/14/2013] [Indexed: 11/29/2022]
|
16
|
An innovative strategy for direct electrochemical detection of microRNA biomarkers. Anal Bioanal Chem 2013; 406:1241-4. [PMID: 23963573 DOI: 10.1007/s00216-013-7292-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Revised: 07/24/2013] [Accepted: 08/05/2013] [Indexed: 01/10/2023]
Abstract
We report an electrochemical method for direct, reagentless, and label-free detection of microRNA, based on a conjugated copolymer, poly(5-hydroxy-1,4-naphthoquinone-co-5-hydroxy-2-carboxyethyl-1,4-naphthoquinone), acting as hybridization transducer. Hybridization between the oligonucleotide capture probe and a microRNA target of 22 base pairs generates an increase in the redox current ("signal-on"), which is evidenced by square wave voltammetry. Selectivity is good, with little hybridization for non-complementary targets, and the limit of detection reaches 650 fM. It is also evidenced that this sensitivity benefits from the high affinity of DNA for RNA.
Collapse
|
17
|
Antibodies Directed to RNA/DNA Hybrids: An Electrochemical Immunosensor for MicroRNAs Detection using Graphene-Composite Electrodes. Anal Chem 2013; 85:8469-74. [DOI: 10.1021/ac402154z] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
|
18
|
Label-Free Electrochemical Immunoaffinity Sensor Based on Impedimetric Method for Pesticide Detection. ELECTROANAL 2013. [DOI: 10.1002/elan.201200331] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
19
|
Appropriate use of bisphosphonates in osteoporosis in cosenza health district (Italy). Eur J Hosp Pharm 2012. [DOI: 10.1136/ejhpharm-2012-000074.451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
|
20
|
Label-free and reagentless electrochemical detection of PCR fragments using self-assembled quinone derivative monolayer: application to Mycobacterium tuberculosis. Biosens Bioelectron 2011; 32:163-8. [PMID: 22186165 DOI: 10.1016/j.bios.2011.11.048] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2011] [Revised: 09/29/2011] [Accepted: 11/30/2011] [Indexed: 11/17/2022]
Abstract
We report a signal-on, label-free and reagentless electrochemical DNA biosensor, based on a mixed self-assembled monolayer of thiolated hydroxynaphthoquinone and thiolated oligonucleotide. Electrochemical changes resulting from hybridization were evidenced with oligonucleotide targets (as models), as well as with polymerase chain reaction (PCR) products related to different lineages of Mycobacterium tuberculosis strains. With pure oligonucleotides, this system achieves high sensitivity (∼300 pM of DNA target, i.e. 30 fmol in a 100 μL sample) and excellent selectivity, allowing to detect a single mismatch on a sequence of 20 bases. With PCR products, current changes are specific to the bacterial strain from which the PCR fragment is produced. In addition, the sensor response is of the signal-on type, giving a positive signal change upon hybridization, and therefore does not suffer from false positive responses due to non-specific adsorption of DNA.
Collapse
|
21
|
Towards the detection of human papillomavirus infection by a reagentless electrochemical peptide biosensor. Electrochim Acta 2011. [DOI: 10.1016/j.electacta.2011.04.094] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
|
22
|
Direct and rapid electrochemical immunosensing system based on a conducting polymer. Talanta 2010; 82:608-12. [DOI: 10.1016/j.talanta.2010.05.015] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2010] [Revised: 04/16/2010] [Accepted: 05/10/2010] [Indexed: 11/29/2022]
|
23
|
Design of a new electrogenerated polyquinone film substituted with glutathione. Towards direct electrochemical biosensors. Talanta 2010; 80:1318-25. [DOI: 10.1016/j.talanta.2009.09.025] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2009] [Revised: 09/03/2009] [Accepted: 09/14/2009] [Indexed: 11/29/2022]
|
24
|
Investigation of the charge effect on the electrochemical transduction in a quinone-based DNA sensor. Electrochim Acta 2008. [DOI: 10.1016/j.electacta.2008.07.087] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
25
|
Fabrication of an interpenetrated network of carbon nanotubes and electroactive polymers to be used in oligonucletide biosensing. Electrochim Acta 2008. [DOI: 10.1016/j.electacta.2007.11.076] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
26
|
Label-free DNA electrochemical sensor based on a PNA-functionalized conductive polymer. Talanta 2008; 76:206-10. [PMID: 18585264 DOI: 10.1016/j.talanta.2008.02.044] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2007] [Revised: 02/08/2008] [Accepted: 02/20/2008] [Indexed: 11/26/2022]
Abstract
An electrochemical hybridization biosensor based on peptide nucleic acid (PNA) probe is presented. PNA were attached covalently onto a quinone-based electroactive polymer. Changes in flexibility of the PNA probe strand upon hybridization generates electrochemical changes at the polymer-solution interface. A reagentless and direct electrochemical detection was obtained by detection of the electrochemical changes using square wave voltammetry (SWV). An increase in the peak current of quinone was observed upon hybridization of probe on the target, whereas no change is observed with non-complementary sequence. In addition, the biosensor is highly selective to effectively discriminate a single mismatch on the target sequence. The sensitivity is also presented and discussed.
Collapse
|
27
|
Ac-electrogravimetry study of ionic exchanges on a polypyrrole modified electrode in various electrolytes. Electrochem commun 2007. [DOI: 10.1016/j.elecom.2007.06.020] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
|
28
|
New frequency/voltage converters for ac-electrogravimetric measurements based on fast quartz crystal microbalance. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2007; 78:074103. [PMID: 17672777 DOI: 10.1063/1.2751093] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
A better understanding of the mechanisms located at the solid/electrolyte interface is becoming essential to the development of new applications in the electrochemical fields. The fast quartz crystal microbalance is an attractive and powerful gravimetric sensor which can be used in the dynamic regime to determine a mass/potential transfer function. The principle is equivalent to classical electrochemical impedance measurements; the only difference is the determination of mass changes given by the quartz crystal microbalance rather than current changes following sine wave modulations of the applied potential. This function appears very well adapted to characterize ionic exchanges at the electrochemical interface. Frequency/voltage converters are the key devices in translating the microbalance frequency response in terms of a continuous voltage change. The latter allows the transfer function to be obtained via a frequency response analyzer. Different converters were tested in this work in order to improve the performances of the experimental setup.
Collapse
|
29
|
Investigations of the steric effect on electrochemical transduction in a quinone-based DNA sensor. Biosens Bioelectron 2007; 22:3126-31. [PMID: 17363240 DOI: 10.1016/j.bios.2007.02.007] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2006] [Revised: 01/19/2007] [Accepted: 02/06/2007] [Indexed: 11/29/2022]
Abstract
Electrochemical biosensors for DNA hybridization are receiving increasing interest. A key point for their efficiency is to obtain a high signal level for low DNA concentration. This implies the design of an efficient transducing surface. Conducting polymers are interesting for this purpose but the great majority of conducting polymer-based electrodes present a signal decrease upon hybridization (a "signal-off" behavior), which impedes their response and makes them sensitive to false positive ones. The sensor described here presents a "signal-on" behavior, due to the use of a quinone group as the transducing agent. The specific aim of this work is to study the steric effect on transduction. To this end, the electrochemical response was monitored versus the DNA target length, for a constant DNA probe length. The results indicate that the current depends on the length of the double strand. A model which can explain the electrochemical behavior takes into account the steric hindrance of the ODN strands.
Collapse
|
30
|
The development of a reagentless lactate biosensor based on a novel conducting polymer. Bioelectrochemistry 2006; 68:218-26. [PMID: 16263338 DOI: 10.1016/j.bioelechem.2005.09.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2005] [Revised: 08/26/2005] [Accepted: 09/02/2005] [Indexed: 10/25/2022]
Abstract
A reagentless lactate biosensor is described, based on an electropolymerized copolymer film poly(5-hydroxy-1,4-naphthoquinone-co-5-hydroxy-3-acetic acid-1,4-naphthoquinone). The quinone group, as part of the polymer backbone, is electroactive and very stable in neutral aqueous medium. It can therefore act as an immobilized mediator for the enzyme recycling, at a working potential much lower than those commonly reported in the literature for other mediators. Experimental conditions for amperometric measurements (temperature, pH) are studied, especially the interference between quinone and molecular oxygen to investigate the enzyme/quinone recycling kinetic. Some well-known interferents are shown to have no measurable effect on the amperometric curves.
Collapse
|
31
|
Direct electrochemical detection of oligonucleotide hybridization on poly(5-hydroxy-1,4-naphthoquinone- co-5-hydroxy-3-thioacetic acid-1,4-naphthoquinone) film. Anal Chem 2004; 75:6748-52. [PMID: 14640757 DOI: 10.1021/ac034770f] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We describe the construction of a new DNA-modified electrode based on an electroactive film. 5-Hydroxy-1,4-naphthoquinone is coelectrooxidized with 5-hydroxy-3-thioacetic acid-1,4-naphthoquinone to give a copolymer, presenting both electroactive and chemically reactive groups. The carboxylic function acts as a precursor for the covalent grafting of ODN probes while the quinone group acts as the transduction element of hybridization. Electrochemical detection was performed by differential pulse voltammetry in the electroactivity domain of the quinone group (i.e., at very low potentials, 0 to -0.8 V vs SCE). A very clear modification of the redox activity is observed between unmodified and probe-modified films and especially upon addition of target ODN.
Collapse
|
32
|
Reagentless amperometric detection of l-lactate on an enzyme-modified conducting copolymer poly(5-hydroxy-1,4-naphthoquinone-co-5-hydroxy-3-thioacetic acid-1,4-naphthoquinone). Biosens Bioelectron 2004; 19:1325-9. [PMID: 15046766 DOI: 10.1016/j.bios.2003.11.006] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2003] [Revised: 11/13/2003] [Accepted: 11/14/2003] [Indexed: 11/29/2022]
Abstract
We have constructed a reagentless lactate sensor using lactate oxidase (LOD) covalently attached to an electropolymerized copolymer film, poly(5-hydroxy-1,4-naphthoquinone-co-5-hydroxy-3-thioacetic acid-1,4-naphthoquinone), poly(JUG-co-JUGA). Around 10(-12)Mcm(-2) of covalently bound enzymes are immobilized on these films. In aerated medium, the amperometric response versus lactate concentration shows a sensitivity of 350 +/- 50 microAM(-1)cm(-2) for an applied potential of +0.5V versus Ag|AgCl on a film-coated Pt electrode. In deaerated medium, the quinone group, conjugated with the polymer backbone, acts as an immobilized mediator. An amperometric response is observed on film-coated glassy carbon (GC) electrode at a potential as low as -0.1V versus Ag|AgCl, with a sensitivity of 110 +/- 40 microAM(-1)cm(-2).
Collapse
|
33
|
|
34
|
Abstract
Oligonucleotides were incorporated into conducting films of poly(3, 4-ethylene dioxythiophene) by an electrochemical method that involves two steps. The electrode is first coated with the polymer film by electropolymerization followed by electrooxidation of the formed polymer in the presence of the oligonucleotide. Neutral water soluble polymers such as poly(vinylpyrrolidone) or poly(ethylene glycol) were added to the polymerizing medium resulting in higher incorporation yields of oligonucleotides. The results showed that a payload of about 1.5 nmol/cm2 can be achieved in an 8 micron thick film for an oligomer concentration of about 70 microM in the working solution. Various physical methods were used to analyze the surface of the polymer-coated electrodes. Results showed the presence of domains of varying sizes at the film surface, corresponding to the insertion of the hydrophilic polymer within the matrix of the conductive polymer. The release of entrapped oligonucleotides from the coated film exhibited a three-step profile: a "burst" period during the first 5 min followed by an intermediate and a very slow release period lasting several days. Such polymer films could be exploited as useful reservoirs of biologically active substances for in vivo delivery to targeted tissues. For example, coated stents that can release antiproliferative agents such as antisense oligonucleotides at the site of balloon dilatation may be of interest in the treatment of postangioplasty restenosis.
Collapse
|