Cystine-assisted accumulation of gold nanoparticles on ZnO to construct a sensitive surface-enhanced Raman spectroscopy substrate

Recently,various semiconductor/metal composites have been developed to fabricate surfaceenhanced Raman spectroscopy substrates.However,low metal loading on semiconductors is still a challenge.In this study,cystine was introduced to increase the accumulation of gold nanoparticles on zinc oxide,owing to the biomineralization_property of_cystine.Morphological analysis revealed that the obtained ZnO/Au/cystine composite not only had a higher metal loading but also formed a porous structure,which is beneficial for Raman performance.Compared with ZnO/Au,the ZnO/Au/cystine substrate displayed a 40-fold enhancement in the Raman signal and a lower limit of detection(10^(-11) mol·L^(-1))in the detection of rhodamine 6G.Moreover,the substrate has favorable homogeneity and stability.Finally,ZnO/Au/cystine displayed excellent performance toward crystal violet and methylene blue in a test based on river water samples.This study provided a promising method to fabricate sensitive semiconductor/noblemetal-based surface-enhanced Ramans spectroscopy substrates for Raman detection.

Detection of breast cancer based on novel porous silicon Bragg reflector surface-enhanced Raman spectroscopy-active structure

In this Letter, the surface-enhanced Raman scattering(SERS) signal of early breast cancer(BRC) patient serum is obtained by a composite silver nanoparticles(Ag NPs) PSi Bragg reflector SERS substrate. Based on these advantages, the serum SERS signals of 30 normal people and 30 early BRC patients were detected by this substrate. After a baseline correction of the experimental data, principal component analysis and linear discriminant analysis were used to complete the data processing. The results showed that the diagnostic accuracy, specificity,and sensitivity of the composite Ag NPs PSi Bragg reflector SERS substrate were 95%, 96.7%, and 93.3%, respectively. The results of this exploratory study prove that the detection of early BRC serum based on a composite Ag NPs PSi Bragg reflector SERS substrate is with a stable strong SERS signal, and an unmarked and noninvasive BRC diagnosis technology. In the future, this technology can serve as a noninvasive clinical tool to detect cancer diseases and have a considerable impact on clinical medical detection.

Noninvasive blood glucose detection using a miniature wearable Raman spectroscopy system

Nowadays, there are about 415 million adults suffering from diabetesN. At present, the treatment for diabetes patients is monitoring their blood glucose level frequently and then taking the appropriate amount of oral hypogly- cemic drugs and insulin to control their blood glucose level.

Raman spectroscopic detection using a two-dimensional echelle spectrometer

In order to meet the high-resolution and wide spectrum range of the backscattering Raman system, this paper designs and builds a Raman test system based on the echelle spectrometer. In the optical splitting system, compared with the ordinary planar grating spectrometer, the use of the echelle improves the resolution of the system without increasing the volume of the system. The use of intensified charge-coupled device(ICCD) in the detection system improves the signal-to-noise ratio(SNR) and the detection limit of weak spectrum. Finally, the Raman system was spectrally calibrated. The broadband backscattering Raman experimental results are given and discussed. The experimental results show that the system has an excellent application prospect for broadband and high-resolution Raman spectrum measurement.

SERS-based mercury ion detections:principles,strategies and recent advances

Mercury ion(Hg^(2+)),known as one of the highly toxic and soluble heavy metal ions,is causing serious environmental pollution and irreversible damage to the health.It is urgent to develop some rapid and ultrasensitive methods for detecting trace mercury ions in the environment especially drink water.Surface-enhanced Raman scattering(SERS)is considered as a novel and powerful optical analysis technique since it has the significant advantages of ultra-sensitivity and high specificity.In recent years,the SERS technique and its application in the detection of Hg^(2+)have become more prevalent and compelling.This review provides an overall survey of the development of SERS-based Hg^(2+)detections and presents a summary relating to the basic principles,detection strategies,recent advances and current challenges of SERS for Hg^(2+)detections.