A surface modification method has been developed to fabricate surface plasmon resonance (SPR) chip for small molecule determination. A novel denaturalised bovine serum albumin (dBSA)‐SPR‐chip was fabricated by a self‐assembling method, while a dextran‐SPR‐chip was prepared by using a traditional method. The surface morphologies of the two chips were investigated by atomic force microscopy technology and their optical properties were characterised by using our home‐made SPR analytical instrument. The surface binding capacity of the dBSA‐SPR‐chip is 2.5 times higher than that of the dextran‐SPR‐chip. On the basis of the experiments of immune reactions between cortisol antibody and cortisol derivative, the sensitivity of the dBSA‐SPR‐chip is much higher than that of the dextran‐SPR‐based SPR‐chip. The antibody concentration was optimised at about 10 µg/ml in order to obtain high sensitivity, which was used in the followed inhibition immunoassays. The lowest detection limit for cortisol is 1 ng/ml with a linear range of 5–100 ng/ml by using the dBSA‐SPR‐chip. These dBSA‐SPR‐chips can also be applied to detect other small molecules based on the indirect inhibitive immunoassay.

Surface plasmon resonance (SPR) biosensors are an extremely sensitive optical technique used to detect the changes in refractive index occurring at the sensor interface. Fluorescence involves the emission of light by a substance that has absorbed light or other electromagnetic radiation, and the parameters of the absorbed and emitted radiation are used to identify the presence and the amount of specific molecules in a specimen. SPR biosensors and fluorescence analysis are both effective methods for real-time detection. The combination of these technologies would improve the quantitative detection sensitivity of fluorescence analysis and the specificity of SPR detection. We designed and developed an SPR and fluorescence synchronous detection system. The SPR module was based on two kinds of modulation methods, and the fluorescence module was capable of switching between four wavelengths. The fluorescence microspheres and A549 cells of different concentration were both detected by the SPR and fluorescence method synchronously in real time. The fluorescent signal and the optical signal of the SPR were shown to correlate. The correlation coefficient for fluorescent microspheres detection reached up to 0.9866. The system could be used in cell analysis and molecule diagnosis in the future.

This paper presents an electrochemical-surface plasmon resonance imaging (EC-SPRI) system, enabling the characterization of optical and electrical properties of cells, simultaneously. The developed surface plasmon resonance (SPR) imaging system was capable of imaging micro cavities with a dimension of 10 μm × 10 μm and differentiated glycerol solutions with a group of refractive indices (RIs). Furthermore, the EC-SPRI system was used to image A549 cells, suggesting corresponding RI and morphology changes during the cell death process. In the end, electrochemical and SPR methods were used in combination, recording oxidation peaks of A549 cells in the cyclic voltage curves and SPR response unit increase, simultaneously.

The survival rate of lung cancer can be significantly improved by monitoring biomarkers in exhaled air that indicate diseases in early stage, so it is very important to develop micro analytical systems which can offer a fast, on-site, real-time detecting biomarkers in exhaled air. In this paper, a mini-gas chromatography (GC)-photo-ionization detector (PID) system integrated with a micro GC column and a micro pre-concentrator was developed for forming an inexpensive, fast, and non-invasive diagnostic tool for lung cancer. This system has very strong concentrate ability owing to its integrated micro pre-concentrator, which make the detection of trace components in exhaled air very easy. In addition, the integrated micro GC column can separate complex mixtures, which overcome low resolution and poor anti-interference ability of other instruments. The results indicated that the mini-GC-PID system can effectively separate and detect the biomarkers at parts-per-billion (ppb) level.

In this reported work, a microfluidic‐based fluid electrokinetic force has been used for surface plasmon resonance or surface plasmon resonance image (SPRI) detection. In this device, a modified rectangular microarray of Au instead of previous reported square or circular gold segments was designed and microfabricated with gold segment geometries and characterised by surface morphology studies. A voltage drop of maximal 400 V/cm was applied without gold erosion to drive fluorescein isothiocyanate isomer I in a high‐conductivity medium on the bare gold surface layer, enabling SPRI detection.