Aptasensor for label-free square-wave voltammetry detection of potassium ions based on gold nanoparticle amplification

An overview of Structured Biosensors for Metal Ions Determination

“…In general, the charge transfer was enhanced after the DNA binding to Cu(II) [130], Pb(II) [102,181], and Hg(II) [9,72,96,98,99,141,149,150]. On the other hand, the formation of a G-quadruplex structure with a K(I) hindered charge transfer [155,156] and led to detection limits as low as 5.0 pg L −1 for application in urine samples. In this case, the high dilution of the sample contributed to minimizing interferences from concomitants that were present at low concentrations in the sample.…”

“…The execution of simple steps such as dip and drop coatings allowed for an easy immobilization of the naturally or synthetically thiolated molecules, such as peptides and DNA strands, after 2 to 12 h of contact with the surface [9,26,36,37,42,44,59,73,98,119,124,127,133,140,143,144,153,156,158,164,165,[167][168][169]172,176]. Alternatively, the gold layer was modified with mercaptohexanol [134,168], hexanethiol [159], and aminothiophenol [154,155] to immobilize the target molecules and nanoparticles. Special attention is needed when executing this approach to avoid the sensor lacking conductivity due to the deposition of high quantities of organic compounds.…”

“…Modifications were carried out with GNP [7,28,36,40,44,48,63,71,73,76,81,131,133,135,139,142,155,158,161,163,167,171,172,[175][176][177], CNTs [11,19,30,69,107,117,162], silver nanoparticles (SNP) [51,138,159], mesoporous carbon [62,73], fullerenes [175], and quantum dots [124,157,184,186]. Coating GE biosensors with GNPs [135,155] aimed to increase the surface area to enhance its sensitivity. The response of the determination of Hg(II) increased up to 60% with a GNP-coated electrode compared to a bare GE [135].…”

“…Over 30% of the proposed procedures for metal determinations employed biosensors modified with nanoparticles. Modifications were carried out with GNP [7,28,36,40,44,48,63,71,73,76,81,131,133,135,139,142,155,158,161,163,167,171,172,[175][176][177], CNTs [11,19,30,69,107,117,162], silver nanoparticles (SNP) [51,138,159], mesoporous carbon [62,73], fullerenes [175], and quantum dots [124,157,184,186]. Coating GE biosensors with GNPs [135,155] aimed to increase the surface area to enhance its sensitivity.…”

Electrochemical Capacitive K+ EMIS Chemical Sensor Based on the Dibromoaza[7]helicene as an Ionophore for Potassium Ions Detection

“…Therefore, maintaining consistent levels of potassium in the blood and cells is vital to any bodily function. The concentration of K + ions in blood is between 3.8 and 5.4 mmol L −1 . For this reason, potassium monitoring is very important in biological systems and in the medical field .…”