• [Inside front cover]SERS‐Active‐Charged Microgels for Size‐ and Charge‐Selective Molecular Analysis of Complex Biological Sample
  • 관리자 |
  • 2018-11-08 13:44:57|
  • 9230

Title: SERSActiveCharged Microgels for Size and ChargeSelective Molecular Analysis of Complex Biological Samples

Author: Dong Jae Kim, SungGyu Park, DongHo Kim,* and ShinHyun Kim*

Journal: Small, 2018, 14, 1802520

Abstract: Surfaceenhanced Raman scattering (SERS) provides a dramatic increase of Raman intensity for molecules adsorbed on nanogaprich metal nanostructures, serving as a promising tool for molecular analysis. However, surface contamination caused by protein adsorption and low surface concentration of small target molecules reduce the sensitivity, which severely restricts the use of SERS in many applications. Here, charged microgels containing agglomerates of gold nanoparticles (Au NPs) are designed using dropletbased microfluidics to provide a reliable SERS substrate with molecular selectivity and high sensitivity. The limiting mesh size of hydrogel enables the autonomous exclusion of large proteins and the charged matrix concentrates oppositely charged small molecules through electrostatic attraction. As nanogaps among Au NPs in the agglomerates enhance Raman intensity, Raman spectrum of the adsorbed molecules is selectively measured with high sensitivity in the absence of interruption from adhesive proteins. Therefore, the SERSactivecharged microgels can be used for direct analysis of pristine biological samples without the pretreatment steps of separation and concentration, which are commonly a prerequisite for Raman analysis. For the purpose of demonstration, a direct detection of fipronil sulfone with partial negative charges, a metabolite of toxic insecticide, dissolved in eggs using the positively charged microgels without any pretreatment of the samples, is shown.