Recent Advances in the Design of Colorimetric Sensors Based on Gold Nanoparticles

NanotechnologyNanotechnology hasDiagnosis expanded rapidly inEnzymes recent years in various biological and engineering fields, specifically in sensorSensor applicationsApplications due to the unique physicalPhysical and chemical characteristicsChemical Characteristics of nanoparticles such as chemical surfaceChemical Surface, sizeSize, shape-dependent electronicsElectronic, controlled manipulation of material at the nanometer length scale, facile functionalizationFacile functionalization with different drugsDrug, improved solubilitySolubility, permeabilityPermeability, targetability, and optimal optical propertiesOptical properties. Specifically, the use of gold nanoparticlesGold nanoparticles is widespread in colorimetricColorimetric assays because of their simple, cost-effectiveCost effective fabricationFabrication, and ease of use. More importantly, changes in the position and intensityIntensity of the gold nanoparticlesGold nanoparticles’ SPR bandSPR band can easily be detected by the naked eye due to a simple visual change in colorColor, which allows easy interpretation of results. In fact, the sensing mechanismsSensing mechanism of the colorimetric sensorsColorimetric Sensors considered here are usually based on the aggregationAggregation/disaggregation phenomenaDisaggregation phenomena of nanoparticles, and the subsequent change in the color of the nanoparticleNanoparticle solutionSolution in the presence of samples, as a result of these physicochemical changesPhysicochemical changes. Recently, the use of nanoparticles in sensingSensing biopolymersBiopolymer has proved to be of particular interest because simple bio-recognition produces significant changes in opticalOptical lightLight absorptionAbsorption, indicating the presence or absence of target analytes without the need for complexComplex and costly equipment. Therefore, in recent years many studies and reviews of gold nanoparticleGold nanoparticles-based colorimetric methodsColorimetric methods have been reported. In this chapter, we focus on the current developments in different colorimetricColorimetric assay designs for the sensing of monomericGemini and gemini surfactantsGemini surfactants, biomoleculesBiomolecule like DNADeoxyribonucleic acid (DNA) and RNARNA, proteinsProtein and virusVirus samples. A special section is dedicated to SAR-CoV-2 detectionSAR-CoV-2 detection. The goldGold standard for diagnosing COVID-19COVID-19 infectionInfection is a reverse transcription real-timeTime polymerase chain reactionPolymerase chain reaction (real-time PCRReal-time PCR). However, in this case it is even more necessary to quickly identify the people capable of spreading the infection. To this end, colorimetric sensorsColorimetric Sensors based on gold nanoparticlesGold nanoparticles stand out as new nanomaterialsNanomaterials for detecting viral particles in biological samples and providing a reliable and rapid responseResponse; there are considerable benefits of this method compared to other detectionDetection methods.