Data augmentation of optical time series signals for small samples.

It is difficult to obtain a large amount of labeled data, which has become a bottleneck for the application of deep learning to analyze one-dimensional optical time series signals. In order to solve this problem, a deep convolutional generative adversarial network model suitable for augmenting optical time series signals is proposed. Based on the acoustic emission (AE) data set obtained by an optical sensor with a small amount, the model can learn the corresponding data features and apply them to generate new data. The analysis results show that our model can generate stable and diverse AE fragments in epoch 500, and there is no model collapse. All the features between the generated data and the original data are not significantly different at the 0.05 level, which confirms that the method in this paper can generate the optical time series signals effectively.

Ultrasensitive sliver nanorods array SERS sensor for mercury ions.

With years of outrageous mercury emissions, there is an urgent need to develop convenient and sensitive methods for detecting mercury ions in response to increasingly serious mercury pollution in water. In the present work, a portable, ultrasensitive SERS sensor is proposed and utilized for detecting trace mercury ions in water. The SERS sensor is prepared on an excellent sliver nanorods array SERS substrate by immobilizing T-component oligonucleotide probes labeled with dye on the 3'-end and -SH on the 5'-end. The SERS sensor responses to the specific chemical bonding between thymine and mercury ions, which causes the previous flexible single strand of oligonucleotide probe changing into rigid and upright double chain structure. Such change in the structure drives the dyes far away from the excellent SERS substrate and results in a SERS signal attenuation of the dye. Therefore, by monitoring the decay of SERS signal of the dye, mercury ions in water can be detected qualitatively and quantitatively. The experimental results indicate that the proposed optimal SERS sensor owns a linear response with wide detecting range from 1pM to 1µM, and a detection limit of 0.16pM is obtained. In addition, the SERS sensor demonstrates good specificity for Hg2+, which can accurately identify trace mercury ions from a mixture of ten kinds of other ions. The SERS sensor has been further executed to analyze the trace mercury ions in tap water and lake water respectively, and good recovery rates are obtained for sensing both kinds of water. With its high selectivity and good portability, the ultrasensitive SERS sensor is expected to be a promising candidate for discriminating mercury ions in the fields of environmental monitoring and food safety.

Combination assay of lung cancer associated serum markers using surface-enhanced Raman spectroscopy.

The development of an ultrasensitive analysis technique for the combination assay of cancer associated markers is an effective method for the early detection of tumor. Herein, we report a highly sensitive and specific SERS-based sandwich immunoassay for the simultaneous detection of two protein markers associated with lung cancer, including carcinoembryonic antigen (CEA) and neuron-specific enolase (NSE). Two bright SERS tags are prepared by surface modifications of flower-like gold nanoparticles with Raman molecules and target-specific antibodies, and SERS-active magnetic nanoparticles labelled with mixed antibodies are used as immune substrates for capturing the targets and further separating the sandwich structured immune complexes from the mixture. Immunoassays for joint detection of CEA and NSE using both buffer and human serum specimens are performed and the assay results indicate that the proposed SERS-based combination assay of the two markers shows good specificity and ultrahigh sensitivity. The limit of detections of CEA and NSE in human serum specimens are 1.48 pg mL-1 and 2.04 pg mL-1, respectively. The proposed SERS immunoassay is expected to be used for multiple-marker assays of any other tumors and to provide a reliable method for the early screening of cancers in clinic.