Noble Metal Nanoparticle-Based Multicolor Immunoassays: An Approach toward Visual Quantification of the Analytes with the Naked Eye

Abstract

Noble metal nanoparticle-based colorimetric sensors have become powerful tools for the detection of different targets with convenient readout. Among the many types of nanomaterials, noble metal nanoparticles exhibit extraordinary optical responses mainly due to their excellent localized surface plasmon resonance (LSPR) properties. The absorption spectrum of the noble metal nanoparticles was mostly in the visible range. This property enables the visual detection of various analytes with the naked eye. Among numerous color change modes, the way that different concentrations of targets represent vivid color changes has been brought to the forefront because the color distinction capability of normal human eyes is usually better than the intensity change capability. We review the state of the art in noble metal nanoparticle-based multicolor colorimetric strategies adopted for visual quantification by the naked eye. These multicolor strategies based on different means of morphology transformation are classified into two categories, namely, the etching of nanoparticles and the growth of nanoparticles. We highlight recent progress on the different means by which biocatalytic reactions mediated LSPR modulation signal generation and their applications in the construction of multicolor immunoassays. We also discuss the current challenges associated with multicolor colorimetric sensors during actual sample detection and propose the future development of next-generation multicolor qualification strategies.

Medical Diagnostic Tests: A Review of Test Anatomy, Phases, and Statistical Treatment of Data

“…The concept of personalized medicine changes the way of health care, the patient becomes the core of the decisional process, and the applied diagnostic methods and/or treatment closely fit the needs and particularities of the patient [242]. Different diagnostic or monitoring devices such as wearable health monitoring systems [243, 244], liquid biopsy or associated approaches [245, 246], wireless ultrasound transducer [247], or other point-of-care testing (POCT) methods [248, 249] are introduced and need proper analysis and validation. Furthermore, the availability of big data opens a new pathway in analyzing medical data, and artificial intelligence approaches will probably change the way of imaging diagnostic and monitoring [250, 251].…”

Gold Recycling at Laboratory Scale: From Nanowaste to Nanospheres

“…Finally, the possible applications of the obtained AuNPs should be considered. Spherical AuNPs have been used for the production of optical [56,57] and Surface Enhanced Raman Spectroscopy based sensors [58,59] and for other medical [60] and biological applications. [61] All these uses require AuNPs with certain sizes, shapes and LSPR band positions.…”

Mild Homogeneous Synthesis of Gold Nanoparticles through the Epoxide Route: Kinetics, Mechanisms, and Related One‐Pot Composites

“…[1] Severalm orphologies and sizes could be obtained nowadays, such as spheres, rods, triangles, bipyramids, among others. [2,3,4] This wide variety of AuNP with well-controlleds izes and shapes was exploited for the production of new opticals ensors, [5,6] sensors based on surface-enhanced Raman spectroscopy, [7,8] more efficient catalysts, [9,10,11,12] and for innovative medical [13,14] and biological applications. [15,16] Depending on the chosen applications, the nanoparticles can be used directly in solution,f orming arrays ontos urfaces [17] or embedded in inorganic or polymericm atrices, in nanocomposites.…”