Ultra-high SERS detection of consumable coloring agents using plasmonic gold nanostars with high aspect-ratio spikes

Abstract

Solution-based SERS detection by using a portable Raman instrument has emerged as an important tool due to its simplicity, and flexibility for rapid and on-site screening of analyte molecules. However,...

Solution-Based Ultra-Sensitive Surface-Enhanced Raman Scattering Detection of the Toxin Bacterial Biomarker Pyocyanin in Biological Fluids Using Sharp-Branched Gold Nanostars

“…Surfactant-free GNS has several advantages over the surfactant-based GNSs synthesis such as morphological tunability and biocompatibility. , However, the surfactant-free GNSs are not stable in long term, and they tend to be agglomerated after a certain period of synthesis, which is probably due to the instability of highly energetic spikes of GNS . In order to utilize highly spiked morphology, we have used polyvinylpyrrolidone (PVP, M w ∼ 8 k) as a capping agent to reduce the aggregation of GNS.…”

“…GNS-3 shows the highest SERS enhancement than GNS-1 and GNS-2, which is probably due to the increased surface area provided for molecular adsorption, in addition to the generation of multiple numbers of hotspots, resulting in strong electromagnetic field enhancement localized at the tips of the GNS-3. 30 Figure 4a displays the SERS data for concentrations of MBA ranging from 1 μM to 1 nM using GNS-3 as an SERS probe. As seen in Figure 4a, the main characteristic peak intensities of MBA at 1078 and 1590 cm −1 increased as the concentration of MBA increased.…”

“…Interestingly, it is reported that the spike does not form without Ag + , and the stability of a star-shaped morphology depends on the Ag + concentration. 43 In this study, we have used three different concentrations of AgNO 3 (15,30, and 120 μM) to achieve GNS-1, GNS-2, and GNS-3 morphology. Figure 1 demonstrates representative STEM images of all the GNSs (GNS-1, GNS-2, and GNS-3), which shows that the average spike number and the spike length were increased with increasing AgNO 3 concentration.…”

“…Among the different sizes and shapes of gold nanoparticles synthesized to date, gold nanostars have attracted great interest in the nanoparticle research community in the last few decades owing to their unique tunable optical properties, excellent biocompatibility, and their application in different fields. − Our group first introduced the use of GNS as an SERS-enhancing platform and subsequently developed the synthesis of biocompatible surfactant-free GNS, and it has been explored in different fields including sensing, imaging, and therapy. − Despite significant advances, there is still a need for further investigation to achieve optimum morphology for maximum SERS enhancement. An ideal morphology of GNS should consist of long spikes with sharp tips that can generate intense local electromagnetic fields. , As such, the goal of this study was to develop an effective plasmonics-active GNS platform that would provide ultra-high SERS enhancement to directly detect bacterial biomarkers such as PYO in biological fluids rapidly without any pre-purification.…”

“…Among the different sizes and shapes of gold nanoparticles synthesized to date, gold nanostars have attracted great interest in the nanoparticle research community in the last few decades owing to their unique tunable optical properties, excellent biocompatibility, and their application in different fields. 30 − 37 Our group first introduced the use of GNS as an SERS-enhancing platform 38 and subsequently developed the synthesis of biocompatible surfactant-free GNS, and it has been explored in different fields including sensing, imaging, and therapy. 39 − 41 Despite significant advances, there is still a need for further investigation to achieve optimum morphology for maximum SERS enhancement.…”