{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,26]],"date-time":"2026-06-26T22:28:04Z","timestamp":1782512884398,"version":"3.54.5"},"reference-count":53,"publisher":"MDPI AG","issue":"11","license":[{"start":{"date-parts":[[2016,11,11]],"date-time":"2016-11-11T00:00:00Z","timestamp":1478822400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>A sensitive and reagentless electrochemical aptatoxisensor was developed on cobalt (II) salicylaldiimine metallodendrimer (SDD\u2013Co(II)) doped with electro-synthesized silver nanoparticles (AgNPs) for microcystin-LR (L, l-leucine; R, l-arginine), or MC-LR, detection in the nanomolar range. The GCE|SDD\u2013Co(II)|AgNPs aptatoxisensor was fabricated with 5\u2019 thiolated aptamer through self-assembly on the modified surface of the glassy carbon electrode (GCE) and the electronic response was measured using cyclic voltammetry (CV). Specific binding of MC-LR with the aptamer on GCE|SDD\u2013Co(II)|AgNPs aptatoxisensor caused the formation of a complex that resulted in steric hindrance and electrostatic repulsion culminating in variation of the corresponding peak current of the electrochemical probe. The aptatoxisensor showed a linear response for MC-LR between 0.1 and 1.1 \u00b5g\u00b7L\u22121 and the calculated limit of detection (LOD) was 0.04 \u00b5g\u00b7L\u22121. In the detection of MC-LR in water samples, the aptatoxisensor proved to be highly sensitive and stable, performed well in the presence of interfering analog and was comparable to the conventional analytical techniques. The results demonstrate that the constructed MC-LR aptatoxisensor is a suitable device for routine quantification of MC-LR in freshwater and environmental samples.<\/jats:p>","DOI":"10.3390\/s16111901","type":"journal-article","created":{"date-parts":[[2016,11,11]],"date-time":"2016-11-11T10:05:56Z","timestamp":1478858756000},"page":"1901","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":39,"title":["Electrochemical Aptatoxisensor Responses on Nanocomposites Containing Electro-Deposited Silver Nanoparticles on Poly(Propyleneimine) Dendrimer for the Detection of Microcystin-LR in Freshwater"],"prefix":"10.3390","volume":"16","author":[{"given":"Mawethu","family":"Bilibana","sequence":"first","affiliation":[{"name":"SensorLab, Department of Chemistry, University of Western Cape, Robert Sobukwe Road, Bellville, Cape Town 7535, South Africa"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Avril","family":"Williams","sequence":"additional","affiliation":[{"name":"Department of Biological and Chemical Sciences, The University of the West Indies, Cave Hill, St. Michael BB11000, Barbados"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Candice","family":"Rassie","sequence":"additional","affiliation":[{"name":"SensorLab, Department of Chemistry, University of Western Cape, Robert Sobukwe Road, Bellville, Cape Town 7535, South Africa"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Christopher","family":"Sunday","sequence":"additional","affiliation":[{"name":"SensorLab, Department of Chemistry, University of Western Cape, Robert Sobukwe Road, Bellville, Cape Town 7535, South Africa"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hlamulo","family":"Makelane","sequence":"additional","affiliation":[{"name":"SensorLab, Department of Chemistry, University of Western Cape, Robert Sobukwe Road, Bellville, Cape Town 7535, South Africa"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lindsay","family":"Wilson","sequence":"additional","affiliation":[{"name":"SensorLab, Department of Chemistry, University of Western Cape, Robert Sobukwe Road, Bellville, Cape Town 7535, South Africa"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nomaphelo","family":"Ntshongontshi","sequence":"additional","affiliation":[{"name":"SensorLab, Department of Chemistry, University of Western Cape, Robert Sobukwe Road, Bellville, Cape Town 7535, South Africa"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Abongile","family":"Jijana","sequence":"additional","affiliation":[{"name":"SensorLab, Department of Chemistry, University of Western Cape, Robert Sobukwe Road, Bellville, Cape Town 7535, South Africa"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Milua","family":"Masikini","sequence":"additional","affiliation":[{"name":"SensorLab, Department of Chemistry, University of Western Cape, Robert Sobukwe Road, Bellville, Cape Town 7535, South Africa"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Priscilla","family":"Baker","sequence":"additional","affiliation":[{"name":"SensorLab, Department of Chemistry, University of Western Cape, Robert Sobukwe Road, Bellville, Cape Town 7535, South Africa"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6102-0433","authenticated-orcid":false,"given":"Emmanuel","family":"Iwuoha","sequence":"additional","affiliation":[{"name":"SensorLab, Department of Chemistry, University of Western Cape, Robert Sobukwe Road, Bellville, Cape Town 7535, South Africa"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2016,11,11]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1383","DOI":"10.1128\/aem.41.6.1383-1388.1981","article-title":"Hemagglutination method for detection of freshwater cyanobacteria (blue-green algae) toxins","volume":"41","author":"Carmichael","year":"1981","journal-title":"Appl. Environ. Microbiol."},{"key":"ref_2","first-page":"2","article-title":"Freshwater Harmful Algal Blooms: Toxins and Children\u2019s Health","volume":"44","author":"Weirich","year":"2014","journal-title":"Curr. Prob. Pediatr. Adolesc. Health Care"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"909","DOI":"10.1016\/j.toxicon.2009.07.006","article-title":"Recreational exposure to microcystins during algal blooms in two California lakes","volume":"55","author":"Backer","year":"2010","journal-title":"Toxicon"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"445","DOI":"10.1111\/j.1365-2672.1992.tb01858.x","article-title":"Cyanobacteria secondary metabolites\u2014The cyanotoxins","volume":"72","author":"Carmichael","year":"1992","journal-title":"J. Appl. Bacteriol."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"2198","DOI":"10.3390\/toxins7062198","article-title":"Cyanobacteria and cyanotoxins occurrence and removal from five high-risk conventional treatment drinking water plants","volume":"7","author":"Szlag","year":"2015","journal-title":"Toxins"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"457","DOI":"10.3390\/toxins7020457","article-title":"Health-based cyanotoxin guideline values allow for cyanotoxin-based monitoring and efficient public health response to cyanobacterial blooms","volume":"7","author":"Farrer","year":"2015","journal-title":"Toxins"},{"key":"ref_7","unstructured":"South Africa. Department of National Health. Directorate of Environmental Health (1996). Recent developments in the local environmental health field. Urban Health Newsl., 28, 87\u201392."},{"key":"ref_8","first-page":"48","article-title":"The effect of water supply, handling and usage on water quality in relation to health indices in developing communities","volume":"32","author":"Genthe","year":"1997","journal-title":"Urban Health Newsl."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"S79","DOI":"10.1080\/02652038909373761","article-title":"WHO drinking water quality guidelines for selected herbicides","volume":"6","author":"Kello","year":"1989","journal-title":"Food Addit. Contam."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"1","DOI":"10.3389\/fchem.2014.00041","article-title":"Aptamer based electrochemical sensors for emerging environmental pollutants","volume":"2","author":"Hayat","year":"2014","journal-title":"Front. Chem."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"419318","DOI":"10.1155\/2015\/419318","article-title":"Single-stranded DNA aptamers against pathogens and toxins: Identification and biosensing applications","volume":"2015","author":"Hong","year":"2015","journal-title":"BioMed Res. Int."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"423","DOI":"10.4062\/biomolther.2013.085","article-title":"Nucleic acid aptamers: New methods for selection, stabilization, and application in biomedical science","volume":"21","author":"Kong","year":"2013","journal-title":"Biomol. Ther."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"1988","DOI":"10.3390\/toxins5111988","article-title":"Aptamers: A promosing tool for ochratoxin a detection in food analysis","volume":"5","author":"Rhouati","year":"2013","journal-title":"Toxins"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"878","DOI":"10.1016\/j.toxicon.2012.06.005","article-title":"Recent trends in development of biosensors for detection of microcystin","volume":"60","author":"Singh","year":"2012","journal-title":"Toxicon"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"10697","DOI":"10.1021\/es301686k","article-title":"Selection, characterization, and biosensing application of high affinity congener-specific microcystin-targeting aptamers","volume":"46","author":"Ng","year":"2012","journal-title":"Environ. Sci. Technol."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"371","DOI":"10.1016\/j.talanta.2012.10.081","article-title":"Determination of microcystin-LR in water by a label-free aptamer based electrochemical impedance biosensor","volume":"103","author":"Lin","year":"2013","journal-title":"Talanta"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"475","DOI":"10.1016\/j.bios.2015.01.037","article-title":"Colorimetric detection of microcystin-LR based on disassembly of orient-aggregated gold nanoparticle dimers","volume":"68","author":"Wang","year":"2015","journal-title":"Biosens. Bioelectron."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"242","DOI":"10.1016\/j.bios.2016.02.072","article-title":"Fabricating photoelectrochemical aptasensor for selectively monitoring microcystin-LR residues in fish based on visible light-responsive BiOBr nanoflakes\/N-doped graphene photoelectrode","volume":"81","author":"Du","year":"2016","journal-title":"Biosens. Bioelectron."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"2","DOI":"10.1038\/pj.2010.109","article-title":"Dendrimer-like star-branched polymers: Novel structurally well-defined hyperbranched polymers","volume":"43","author":"Hirao","year":"2011","journal-title":"Polym. J."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"474","DOI":"10.1016\/j.bios.2012.11.003","article-title":"Dendrimer functionalized reduced graphene oxide as nanocarrier for sensitive pseudobienzyme electrochemical aptasensor","volume":"42","author":"Yuan","year":"2013","journal-title":"Biosens. Bioelectron."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"4278","DOI":"10.1021\/ac404070m","article-title":"Sensitive electrochemical aptamer biosensor for dynamic cell surface N-glycan evaluation featuring multivalent recognition and signal amplification on a dendrimer\u2013graphene electrode interface","volume":"86","author":"Chen","year":"2014","journal-title":"Anal. Chem."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"6478","DOI":"10.1021\/jp9106052","article-title":"Immobilization of poly(propylene imine) dendrimer\/nickel phtalocyanine as nanostructured multilayer films to be used as gate membranes for SEGFET pH sensors","volume":"114","author":"Fernandes","year":"2010","journal-title":"J. Phys. Chem. C"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"5518","DOI":"10.1021\/om000601z","article-title":"Reaction of (chlorocarbonyl)metallocenes of iron and cobalt with 1,4-diaminobutane:\u2009 Synthesis of a heterobimetallic ferrocene\u2212cobaltocenium complex","volume":"19","author":"Cuadrado","year":"2000","journal-title":"Organometallics"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"124","DOI":"10.1016\/j.apcata.2005.05.049","article-title":"Nanocomposite catalysts: Dendrimer encapsulated nanoparticles immobilized in sol\u2013gel silica","volume":"292","author":"Beakley","year":"2005","journal-title":"Appl. Catal. A"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"692","DOI":"10.1021\/jp0469665","article-title":"Synthesis, characterization, and applications of dendrimer-encapsulated nanoparticles","volume":"109","author":"Scott","year":"2005","journal-title":"J. Phys. Chem. B"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"915","DOI":"10.1016\/j.bios.2015.07.064","article-title":"Ultrasensitive electrochemical immunosensor for PSA biomarker detection in prostate cancer cells using gold nanoparticles\/PAMAM dendrimer loaded with enzyme linked aptamer as integrated triple signal amplification strategy","volume":"74","author":"Kavosi","year":"2015","journal-title":"Biosens. Bioelectron."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"7343","DOI":"10.3390\/s90907343","article-title":"Nanomaterial-assisted signal enhancement of hybridization for DNA biosensors: A review","volume":"9","author":"Liu","year":"2009","journal-title":"Sensors"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"1686","DOI":"10.1002\/cbic.200400080","article-title":"Effect of silver nanoparticles on the electron transfer reactivity and the catalytic activity of myoglobin","volume":"5","author":"Gan","year":"2004","journal-title":"ChemBioChem"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"1674","DOI":"10.1021\/cm000416b","article-title":"Synthesis of dendrimer-passivated noble metal nanoparticles in a polar medium:\u2009 Comparison of size between silver and gold particles","volume":"13","author":"Manna","year":"2001","journal-title":"Chem. Mater."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"20","DOI":"10.1016\/j.bios.2013.08.012","article-title":"A highly sensitive prostate-specific antigen immunosensor based on gold nanoparticles\/PAMAM dendrimer loaded on MWCNTS\/chitosan\/ionic liquid nanocomposite","volume":"52","author":"Kavosi","year":"2014","journal-title":"Biosens. Bioelectron."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"97","DOI":"10.1016\/j.msec.2015.08.013","article-title":"Direct electrochemistry of hemoglobin and biosensing for hydrogen peroxide using a film containing silver nanoparticles and poly(amidoamine) dendrimer","volume":"58","author":"Baccarin","year":"2016","journal-title":"Mater. Sci. Eng. C"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"4296","DOI":"10.1016\/j.electacta.2009.06.065","article-title":"Electrochemical and spectroscopic properties of dendritic cobalto-salicylaldiimine DNA biosensor","volume":"55","author":"Martinovic","year":"2010","journal-title":"Electrochim. Acta"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"285","DOI":"10.1016\/S0300-483X(03)00112-4","article-title":"Comparative toxicity evaluation of cyanobacterial cyclic peptide toxin microcystin variants (LR, RR, YR) in mice","volume":"188","author":"Gupta","year":"2003","journal-title":"Toxicology"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"11679","DOI":"10.3390\/s111211679","article-title":"Amperometric immunosensor based on a protein A\/deposited gold nanocrystals modified electrode for carbofuran detection","volume":"11","author":"Sun","year":"2011","journal-title":"Sensors"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"492","DOI":"10.1016\/j.bios.2012.10.060","article-title":"Electrochemical impedance spectroscopic technique with a functionalized microwire sensor for rapid detection of foodborne pathogens","volume":"42","author":"Lu","year":"2013","journal-title":"Biosens. Bioelectron."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"7098","DOI":"10.1039\/c3nr02176a","article-title":"Supramolecular self-assemblies as functional nanomaterials","volume":"5","author":"Busseron","year":"2013","journal-title":"Nanoscale"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"8916","DOI":"10.1021\/ja9719586","article-title":"Characterization of DNA probes immobilized on gold surfaces","volume":"119","author":"Herne","year":"1997","journal-title":"J. Am. Chem. Soc."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"612","DOI":"10.3390\/s120100612","article-title":"Aptamers and their biological applications","volume":"12","author":"Song","year":"2012","journal-title":"Sensors"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"3653","DOI":"10.1021\/nn400659m","article-title":"Nanoscale spatial distribution of thiolated DNA on model nucleic acid sensor surfaces","volume":"7","author":"Josephs","year":"2013","journal-title":"ACS Nano"},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"1265","DOI":"10.2116\/analsci.26.1265","article-title":"Label-free electrochemical cocaine aptasensor based on a target-inducing aptamer switching conformation","volume":"26","author":"Hua","year":"2010","journal-title":"Anal. Sci."},{"key":"ref_41","unstructured":"Gu, B.M., and Kim, H.-S. (2014). Exploration of Structure-Switching in the Design of Aptamer Biosensors, in Biosensors Based on Aptamers and Enzymes, Springer."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"610","DOI":"10.1016\/j.jhazmat.2009.09.095","article-title":"First evidence of estrogenic potential of the cyanobacterial heptotoxins the nodularin-R and the microcystin-LR in cultured mammalian cells","volume":"174","author":"Oziol","year":"2010","journal-title":"J. Hazard. Mater."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"408","DOI":"10.1007\/s00216-003-2162-0","article-title":"Approaches to bioresponse-linked instrumental analysis in water analysis","volume":"377","author":"Obst","year":"2003","journal-title":"Anal. Bioanal. Chem."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"151","DOI":"10.1590\/S1516-89132012000100019","article-title":"Biomonitoring of microcystin and aflatoxin co-occurrence in aquaculture using immunohistochemistry and genotoxicity assays","volume":"55","author":"Hashimoto","year":"2012","journal-title":"Braz. Arch. Biol. Technol."},{"key":"ref_45","doi-asserted-by":"crossref","unstructured":"Niedermeyer, T.H.J., Daily, A., Swiatecka-Hagenbruch, M., and Moscow, J.A. (2014). Selectivity and potency of microcystin congeners against OATP1B1 and OATP1B3 expressing cancer cells. PLoS ONE, 9.","DOI":"10.1371\/journal.pone.0091476"},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"7551","DOI":"10.1021\/ac501335k","article-title":"Label-free voltammetric aptasensor for the sensitive detection of microcystin-LR using graphene-modified electrodes","volume":"86","author":"Eissa","year":"2014","journal-title":"Anal. Chem."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"9181","DOI":"10.3390\/s120709181","article-title":"A unifying review of bioassay-guided fractionation, effect-directed analysis and related techniques","volume":"12","author":"Weller","year":"2012","journal-title":"Sensors"},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"5980","DOI":"10.1021\/ac0705723","article-title":"Quantitative analysis of cyanobacterial toxins by matrix-assisted laser desorption ionization mass spectrometry","volume":"79","author":"Howard","year":"2007","journal-title":"Anal. Chem."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"93","DOI":"10.1016\/j.aca.2012.10.009","article-title":"Liquid chromatographic determination of microcystins in water samples following pre-column excimer fluorescence derivatization with 4-(1-pyrene)butanoic acid hydrazide","volume":"755","author":"Hayama","year":"2012","journal-title":"Anal. Chim. Acta"},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"2346","DOI":"10.1016\/j.bios.2008.12.003","article-title":"Portable optical immunosensor for highly sensitive detection of microcystin-LR in water samples","volume":"24","author":"Long","year":"2009","journal-title":"Biosens. Bioelectron."},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"299","DOI":"10.1007\/s00604-011-0557-8","article-title":"Label-free immunosensing of microcystin-LR using a gold electrode modified with gold nanoparticles","volume":"173","author":"Tong","year":"2011","journal-title":"Microchim. Acta"},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"1807","DOI":"10.1002\/adfm.201201920","article-title":"A multiwalled-carbon-nanotube-based biosensor for monitoring microcystin-LR in sources of drinking water supplies","volume":"23","author":"Han","year":"2013","journal-title":"Adv. Funct. Mater."},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"38","DOI":"10.1016\/j.colsurfb.2012.10.010","article-title":"A graphene and multienzyme functionalized carbon nanosphere-based electrochemical immunosensor for microcystin-LR detection","volume":"103","author":"Zhao","year":"2013","journal-title":"Colloids Surf. B"}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/16\/11\/1901\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T19:35:20Z","timestamp":1760211320000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/16\/11\/1901"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2016,11,11]]},"references-count":53,"journal-issue":{"issue":"11","published-online":{"date-parts":[[2016,11]]}},"alternative-id":["s16111901"],"URL":"https:\/\/doi.org\/10.3390\/s16111901","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2016,11,11]]}}}