A Simple Assay for Direct Colorimetric Visualization of Trinitrotoluene at Picomolar Levels Using Gold Nanoparticles

Abstract

Explosive Situation: Pikomolare Mengen von Trinitrotoluol (TNT) lassen sich mithilfe von Goldnanopartikeln und Cysteamin sichtbar machen; dabei wird die Donor‐Akzeptor‐Wechselwirkung zwischen TNT und Cysteamin genutzt (siehe Bild). Der Farbwechsel von Rot nach Blau lässt sich mit bloßem Auge beobachten, was eine empfindliche Detektion an Ort und Stelle ermöglicht.

Utilization of unmodified gold nanoparticles in colorimetric detection

“…The target DNA hybridized with the fully complementary probe DNA on nanoparticles, which led to the large-scale aggregation of AuNPs, bringing a visible color transition from red to purple [32][33][34]. During the following decades, colorimetric detection based on AuNPs towards various targets has been extensively investigated including DNA [35][36][37], proteins [38][39][40], small organic molecules [41][42][43][44][45], and ions, such as mercury(II) [46][47][48], lead(II) [49,50], copper(II) [51,52], calcium(II) [53], uranium(II) [54] and nitrite [55].…”

Disposable immunoassay for hepatitis B surface antigen based on a graphene paste electrode functionalized with gold nanoparticles and a Nafion-cysteine conjugate

“…AuNPs were prepared by a trisodium citrate reduction method as reported before [20]. Briefly, trisodium citrate (5 mL, 38.8 mM) was rapidly added to a boiling solution of HAuCl 4 (50 mL, 1 mM), and the solution was kept continually boiling for another 30 min to give a wine-red solution.…”

A colorimetric sensor array for detection and discrimination of biothiols based on aggregation of gold nanoparticles

“…More specifically, chemical tongue/nose approach is used to produce a specific pattern for individual analyte, rather than using selective interactions, to achieve multi-dimensional detection [17][18][19][20][21]. Due to their diverse advantages such as low cost, variety of detection modes (e.g., change in absorbance and color, optical layer thickness, and light polarization) and diversity of collection devices (e.g., CCD, CMOS cameras, photodiodes, scanners, and spectrophotometer) [22], the optical based array sensors (compared to other type of sensor arrays sensor arrays (e.g., fluorescence, potential, resistance, and current)) are able to detect a wide range of analytes (e.g., toxic gases [23][24][25], explosives [26][27][28] and organic molecules [29,30]), complex mixtures (e.g., foods [31,32], beverages [33][34][35][36], and pharmaceutical products [37]). …”