Micro-hyperspectral technology combines hyperspectral imaging and microscopic imaging technology to obtain the spatial and spectral information of samples simultaneously. Because of its rapidity and nondestructive character, micro-hyperspectral technology has shown immense potential in the biomedical field. In this study, we employed self-assembled micro-hyperspectral imaging (MHSI) system to image A549 cells (human non-small cell lung cancer), introducing gold nanoparticles (AuNPs) as the contrast agents to increase the image signal-to-noise ratio. The result shows that spectrum information distinguishes the optical absorption capabilities of nanoparticles from that of other sources in the cellular environment. Currently, given the experimental restrictions, AuNPs cannot be observed directly, but the location of gold nanoparticles can be identified by the specific spectrum. To analyze hyperspectral three-dimensional cell images and quantitatively analyze the submicroscopic structure of lung cancer cells, the space-spectral feature fusion algorithm is utilized. According to the preliminary results, micro-hyperspectral imaging technology highlights the potential application for subcellular diagnosis, but the image segmentation of cells without contrast agents yields erroneously classified results; the outcomes of cell segmentation for A549 cells' uptake of AuNPs indicate that the cellular structure is distinct. However, there are still misclassifications since AuNPs lack a specialized targeting function. Taking into consideration the current challenges, our next objective is to execute surface modification on AuNPs as probes to target particular sections of living cells to improve the resolution of cell submicroscopic structure imaging. In conclusion, MHSI technology can effectively characterize the submicroscopic structure of cells and show a wide range of potential bioimaging applications.
Fluorescent molecules play an important role in many fields due to their characteristic of high sensitivity and easy operation. The traditional method for detecting fluorescent molecules is Laser Scanning Confocal Microscopy, but it has light pollution and can only detect a single class of fluorescent molecules at once. Recently, Microscopic Hyperspectral Imaging(MHSI) technology has been used to the detection of fluorescent molecules due to its high spectral resolution and non-destructive detection. However, the low spatial resolution of MHSI makes it difficult to conduct high-precision molecular research. Therefore, it is important to develop an image processing method to improve it. In this work, a twostep data processing method was proposed to enhance automatic classification effect of fluorescent molecules. We used a microscopic hyperspectral system to image the mixed five kinds of fluorescent molecular samples in transmission mode. The first step is based on the difference in unit slope of spectra curve (wavelength range was chosen from 410 nm to 550 nm) between fluorescence molecule and the background, and an image segmentation method based on minimum light transmission point is proposed. The second step is to calculate the relative absorbance of each voxel according to the nearest background voxel found on the basis of image segmentation, and to take the absorbance as the final classification feature. Compared with the traditional transmittance feature on six kinds of machine learning classification models, the average classification accuracy of the new features can be improved by 2.2%, and the time consumption per classification can be reduced by 1/3 approximately. In conclusion, the proposed two-step data processing method is suitable for the classification of multi-kinds of fluorescent molecules, which has the advantages of high efficiency and accuracy, and is expected to be widely used in biology, medicine, materials and other fields.
Perovskites have been widely used in solar cells manufacturing due to their extraordinary photoelectric characteristics. The crystal quality of perovskite plays an important role in photoelectric conversion. Although conventional crystal quality detection methods, such as scanning electron microscopy(SEM) and atomic force microscope(AFM), have good performance of high spatial resolution, they are usually time-consuming, expensive, and sometimes damage the samples unavoidably. Hyperspectral imaging(HSI) technology has been utilized to monitor material growth process in recent years, due to its advantages of high spectral resolution, non-invasive and fast detection speed. Micro-hyperspectral imaging(MHSI) technology combines both HSI and microscopic technology, enabling it suitable for micro- and nanoscale material analysis. In this work, we have developed a kind of MHSI system. 3D data of perovskite monocrystals were obtained by transmission mode at room temperature. Perovskite mono-crystals were prepared by one-step solution self-assembly method. The experimental results illustrate that the specific absorption wavelength of perovskite is directly proportional to the thickness of mono-crystals. When the thickness increases, the absorption wavelength will shift red. The thickness factor is also verified by white light interference. The composition ratio of perovskite monocrystals has a certain dependence on its absorbance before 540 nm. The higher the proportion of Br atom is, the weaker the light absorption is, and auxiliary verification was carried out by energy dispersive spectrometer(EDS). In conclusion, MHSI technology can effectively monitor and analyze the preparation process and quality evaluation of micro- and nanoscale materials and structure, it shows a wide application prospect in material science and medical fields.
In this study, we have developed a kind of single-layer graphene-based surface plasmon resonance (SLG-SPR) biosensor with wavelength interrogation to detect C-reactive protein (CRP) by sandwich immunoassay. For the nature of the biosensor itself, with the decrease of the incidence angle (θ), resonance wavelength (λR) increased gradually. The refractive index sensitivity (S) and θ are inversely proportional relationship while S and λR are positively proportional relationship. Then we studied two kinds of sensitivity properties of these two SPR biosensors respectively. The refractive index (RI) sensitivity of the two biosensors is approximately the same and the high sensitivity of SLG-SPR biosensor due to the excellent adsorption properties of graphene. The experiment shows that the changes in resonance wavelength (▵λR) of SLG-SPR biosensor are higher than that of the gold film based SPR (Au-SPR) biosensor when the final sandwich structures were formed. Meanwhile, we have applied the Fresnel reflection equations and Bruggeman approximation formula to calculate the volume fractions of adsorbates in different adlayers, and the dispersion curves of the effective RI of adsorbates with different volume fractions of adlayers and the cAb isothermal adsorption curves that conforms to Langmuir equation were obtained. In conclusion, the SLG-SPR biosensor with a higher detection sensitivity than the conventional Au-SPR biosensor in detecting CRP and it has the advantages of low-cost, stability, highly efficient for the clinical determination of CRP levels.
In this work, we developed a kind of gold-silver alloy film based surface plasmon resonance (AuAg-SPR) biosensors with wavelength interrogation to detect C-reaction protein (CRP) by using gold nanoparticles (AuNPs)-enhanced sandwich immunoassay, and the limit of detection (LOD) of CRP was found to be 5 pg/ml . In conclusion, using the AuNPsenhanced sandwich immunoassay and the SPR chip of AuAg alloy film can detect CRP effectively and reduce the LOD significantly, and this improvement can also be applied for the detection of any biomarkers in low concentration accurately.
In this study, we developed a kind of gold-silver alloy film based SPR (AuAg-SPR) sensors with wavelength interrogation to detect Cancer antigen 125 (CA125) by sandwich immunoassay. The experiment shows that the changes in resonance wavelength (Δλ𝑅) of AuAg-SPR sensors are higher than that of the gold film based SPR (Au-SPR) sensors when the final sandwich structures were formed. We have applied the Fresnel reflection equations and Bruggeman approximation formula to calculate the volume fractions of adsorbates in different adlayers, and the dispersion curves of the effective refractive index (RI) of adsorbates with different volume fractions of adlayers were obtained. Moreover, we simulated the sensitivity of RI of two kinds of sensors by using the waveguide equations, when the initial resonance wavelength (λ𝑅) was fixed at 628nm, changing RI from 1.333 to 1.335, the Δλ𝑅 of AuAg-SPR sensor is 2.25-fold compared with that of Au-SPR sensor. Finally, the effect of the size of antigen on the detection result and effective RI were analyzed. In conclusion, the AuAgSPR sensors with a higher sensitivity than the conventional Au-SPR sensors in detecting CA125, owing to the advantages of low-cost, stability, highly efficient for the clinical determination of CA125 levels
Layer-by-layer self-assembly ultrathin films continue to be of significant interest among researchers for its broad application in diverse areas. Based on electrostatic attraction between materials with opposite charges, multilayer films of (PSS/Cyt c) 6, (GNPs/Cyt c) 5 and (PDDA/DNA) 6 had been successfully fabricated on the surface of gold chip, respectively. The adsorption process had been followed by in suit spectral surface plasmon resonance (SPR) technique in real time. The experimental results demonstrate that adsorption of materials onto the gold chip can induce a redshift of resonance wavelength and the amount of adsorption can be determined by the change of resonance wavelength. Kinetics studies suggest that adsorption of cytochrome c (Cyt c) or deoxy ribonucleic acid (DNA) obeys Langmuir-isotherm theory, while adsorption of gold nanoparticles (GNPs) obey diffusion-controlled model. These results also indicate that GNPs need more time to reach adsorption equilibrium than Cyt c and DNA, due to a small value of diffusion coefficient.0 increasing with the layer, however, (GNPs/Cyt c) 5 and (PDDA/DNA) 6 show a nonlinearly increase. Moreover, through controlling the number of assembled layer, the thickness of multilayer films can be precise designed.
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