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Open AccessArticle

Silver SERS Adenine Sensors with a Very Low Detection Limit

Department of Electrical Engineering, National Cheng Kung University, Tainan 701, Taiwan
Author to whom correspondence should be addressed.
Biosensors 2020, 10(5), 53;
Received: 5 April 2020 / Revised: 12 May 2020 / Accepted: 13 May 2020 / Published: 15 May 2020
(This article belongs to the Special Issue SERS-Spectroscopy for Biosensing)
The detection of adenine molecules at very low concentrations is important for biological and medical research and applications. This paper reports a silver-based surface-enhanced Raman scattering (SERS) sensor with a very low detection limit for adenine molecules. Clusters of closely packed silver nanoparticles on surfaces of discrete ball-like copper bumps partially covered with graphene are deposited by immersion in silver nitrate. These clusters of silver nanoparticles exhibit abundant nanogaps between nanoparticles, where plasmonic coupling induces very high local electromagnetic fields. Silver nanoparticles growing perpendicularly on ball-like copper bumps exhibit surfaces of large curvature, where electromagnetic field enhancement is high. Between discrete ball-like copper bumps, the local electromagnetic field is low. Silver is not deposited on the low-field surface area. Adenine molecules interact with silver by both electrostatic and functional groups and exhibit low surface diffusivity on silver surface. Adenine molecules are less likely to adsorb on low-field sensor surface without silver. Therefore, adenine molecules have a high probability of adsorbing on silver surface of high local electric fields and contribute to the measured Raman scattering signal strength. We demonstrated SERS sensors made of clusters of silver nanoparticles deposited on discrete ball-like copper bumps with very a low detection limit for detecting adenine water solution of a concentration as low as 10−11 M. View Full-Text
Keywords: SERS; silver; adenine; R6G; graphene; plasmon; Raman scattering; copper SERS; silver; adenine; R6G; graphene; plasmon; Raman scattering; copper
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MDPI and ACS Style

Tzeng, Y.; Lin, B.-Y. Silver SERS Adenine Sensors with a Very Low Detection Limit. Biosensors 2020, 10, 53.

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