Synergistic Physical and Chemical Enhancement Effects Observed on Surface-Enhanced Raman Spectroscopy Substrates of Silver-Coated, Barrier-Type Anodic Alumina

2020 ◽  
Vol 124 (24) ◽  
pp. 13316-13328
Author(s):  
Sherif Okeil ◽  
Mikhail Pashchanka ◽  
Silvio Heinschke ◽  
Michael Bruns ◽  
Jörg J. Schneider
Keyword(s):  
Raman Spectroscopy ◽  
Surface Enhanced Raman Spectroscopy ◽  
Anodic Alumina ◽  
Chemical Enhancement ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Barrier Type ◽  
Physical And Chemical

Two Mechanisms of Tip Enhancement of Raman Scattering by Protein Aggregates

2016 ◽  
Vol 71 (1) ◽  
pp. 118-128 ◽  
Author(s):  
Valentin Sereda ◽  
Igor K. Lednev
Keyword(s):  
Raman Spectroscopy ◽  
Raman Scattering ◽  
Surface Enhanced Raman Spectroscopy ◽  
Biological Species ◽  
Chemical Enhancement ◽  
Cast Film ◽  
Surface Enhanced Raman ◽  
Type Spectrum ◽  
Tip Enhanced Raman Spectroscopy ◽  
Physical And Chemical

Tip-enhanced Raman spectroscopy (TERS) is a powerful tool for probing the surface of biological species with nanometer spatial resolution. Here, we report the TER spectra of an individual insulin fibril, the protein cast film and a short peptide (LVEALYL) microcrystal mimicking the fibril core. Two different types of TER spectra were acquired depending on the “roughness” of the probed surface at the molecular level. A fully reproducible, low-intensity, normal Raman-type spectrum was characteristic of the top flat surface of the microcrystal while highly variable, higher intensity TER spectra were obtained for the edges of the microcrystal, cast film, and fibril. As a result, two tip enhancement mechanisms of Raman scattering, long- and short-range, were proposed by analogy with the physical and chemical enhancement mechanisms, respectively, known for surface-enhanced Raman spectroscopy.

Bacterial detection and differentiation via direct volatile organic compound sensing with surface enhanced Raman spectroscopy

2017 ◽  
Author(s):  
Caitlin S. DeJong ◽  
David I. Wang ◽  
Aleksandr Polyakov ◽  
Anita Rogacs ◽  
Steven J. Simske ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Bacterial Infections ◽  
Direct Detection ◽  
Point Of Care ◽  
Surface Enhanced Raman Spectroscopy ◽  
E Coli ◽  
Recent Emergence ◽  
Surface Enhanced ◽  
Volatile Organic ◽  
Surface Enhanced Raman

Through the direct detection of bacterial volatile organic compounds (VOCs), via surface enhanced Raman spectroscopy (SERS), we report here a reconfigurable assay for the identification and monitoring of bacteria. We demonstrate differentiation between highly clinically relevant organisms: <i>Escherichia coli</i>, <i>Enterobacter cloacae</i>, and <i>Serratia marcescens</i>. This is the first differentiation of bacteria via SERS of bacterial VOC signatures. The assay also detected as few as 10 CFU/ml of <i>E. coli</i> in under 12 hrs, and detected <i>E. coli</i> from whole human blood and human urine in 16 hrs at clinically relevant concentrations of 10<sup>3</sup> CFU/ml and 10<sup>4</sup> CFU/ml, respectively. In addition, the recent emergence of portable Raman spectrometers uniquely allows SERS to bring VOC detection to point-of-care settings for diagnosing bacterial infections.

Sign in / Sign up

Export Citation Format

Share Document