Fully connected neural network-based serum surface-enhanced Raman spectroscopy accurately identifies non-alcoholic steatohepatitis.

BACKGROUND/PURPOSE OF THE STUDY: There is a need to find a standardized and low-risk diagnostic tool that can non-invasively detect non-alcoholic steatohepatitis (NASH). Surface enhanced Raman spectroscopy (SERS), which is a technique combining Raman spectroscopy (RS) with nanotechnology, has recently received considerable attention due to its potential for improving medical diagnostics. We aimed to investigate combining SERS and neural network approaches, using a liver biopsy dataset to develop and validate a new diagnostic model for non-invasively identifying NASH. METHODS: Silver nanoparticles as the SERS-active nanostructures were mixed with blood serum to enhance the Raman scattering signals. The spectral data set was used to train the NASH classification model by a neural network primarily consisting of a fully connected residual module. RESULTS: Data on 261 Chinese individuals with biopsy-proven NAFLD were included and a prediction model for NASH was built based on SERS spectra and neural network approaches. The model yielded an AUROC of 0.83 (95% confidence interval [CI] 0.70-0.92) in the validation set, which was better than AUROCs of both serum CK-18-M30 levels (AUROC 0.63, 95% CI 0.48-0.76, p = 0.044) and the HAIR score (AUROC 0.65, 95% CI 0.51-0.77, p = 0.040). Subgroup analyses showed that the model performed well in different patient subgroups. CONCLUSIONS: Fully connected neural network-based serum SERS analysis is a rapid and practical tool for the non-invasive identification of NASH. The online calculator website for the estimated risk of NASH is freely available to healthcare providers and researchers ( http://www.pan-chess.cn/calculator/RAMAN_score ).

[Studies of Male Fertility with Raman Spectroscopy].

Raman spectroscopy which belongs to scattering spectroscopy obtained molecular vibrational and rotational information to achieve detection and analysis of molecular structure and corresponding changes through recording the frequency shift when light interacted with materials. Compared with routine biochemical analysis, Raman spectroscopy has the advantage of non-invasive, label-free and no sample requirement. Raman spectroscopy has been widely applied in biomedical field such as human tissue, organs, cells and human body fluids for disease diagnosis. This article mainly focuses on recent research advances of Raman spectroscopy in human semen. Firstly, Raman spectroscopy(including surface-enhanced Raman spectroscopy, SERS) employed in forensic science for semen analysis, and some related data processing methods were introduced, then Raman spectroscopy involved investigations of male fertility was highlighted, more specifically, the Raman-based qualitative and quantitative analysis which assist the objective detection and evaluation of male fertility. Furthermore, studies of single sperm cell based on micro-Raman system to characterize and evaluate sperm quality and the preliminarily obtained Raman biomarkers which indicate high-quality sperm cell were introduced. Finally, the potential development of Raman spectroscopy involved in reproduction and fertility field was also discussed.

Evaluation of collagen alteration after topical photodynamic therapy (PDT) using second harmonic generation (SHG) microscopy--in vivo study in a mouse model.

Topical photodynamic therapy (PDT) mediated by 5-aminolevulinic acid (ALA) has been used for the treatment of age-related skin lesions for therapeutic or cosmetic purposes. The modulation of collagen component and structure might play a significant role in influencing treatment outcomes of PDT. In this study, the effect of multi-session low dose ALA PDT on skin rejuvenation was examined in a hairless mouse model. Changes in collagen and skin texture were investigated by histological examination and in vivo second harmonic generation (SHG) microscopy. Results indicated that multi-session PDT could improve the collagen density and arrangement of skin tissue. SHG microscopy combined with quantitative collagen analysis could provide a useful tool for the evaluation of collagen alteration induced by ALA PDT.

[Raman spectral analysis of theanine].

The L-theanine was tested using confocal Raman microscopy. Obvious Raman bands were showed in the range of 250 -1 700 and 2 800-3 000 cm(-1). The Raman bands were assigned with a preliminary analysis and the characteristic vibrational modes were gained in different range of wave numbers. Eight strong Raman bands were observed in the Raman spectra at 321, 900, 938, 1 153, 1 312, 1 358, 1 454 and 1 647 cm(-1), respectively. They are the characteristic Raman bands of L-theanine. The results showed that Raman spectroscopy might be a new kind of precise, direct and fast detecting method for theanine.

[Fluorescence spectra and imaging of Platymonas subcordiformis via LSCM].

Primary investigation of Platymonas subcordiformis was performed with laser scanning microscopic technology. Both autofluorescence spectra and autofluorescence imaging of Platymonas subcordiformis were achieved by one photon excitation of 488 nm Ar+ laser. Autofluorescence images revealed cup-shaped object inside the Platymonas subcordiformis cell, and the corresponding fluorescence peak located at 682 nm was attributed to chloroplast. Moreover, in single channel mode, there existed a round-shaped object in chloroplast center, showing strong fluorescence by 800 nm femtosecond laser excitation. Also, the authors obtained both the individual cup-shaped chloroplast and round-shaped object image and the overlaid images by using dual-channel mode. Meanwhile, six main fluorescence peaks were found. Single photon excitation can be used to obtain autofluorescence image and autofluorescence spectra of Platymonas subcordiformis, while two photon excitation combined with multitrack mode and Lambda mode can be used not only to observe internal structure, but also for the analysis of existence of biological and chemical substances with higher sensitivity than single photon excitation. LSCM technique can be a promising tool for rapid, convenient, real-time and effective investigation in ocean algae.

[Near infrared Raman spectra analysis of rhizoma dioscoreae].

A novel and compact near-infrared (NIR) Raman system was developed using 785 nm diode laser, volume-phase technology holographic system, and NIR intensified charge-coupled device (CCD). The Raman spectra and first derivative spectra of rhizoma dioscoreae were obtained. The Raman spectra of rhizoma dioscoreae showed three strong characteristic peaks at 477, 863 and 936 cm(-1), respectively. The major ingredients are protein, amino acid, starch, polysaccharides and so on, matching the known basic biochemical composition of rhizoma dioscoreae. In the first derivative spectra of rhizoma dioscoreae, the distinguishing characteristic peaks appeared at 467, 484, 870 and 943 cm(-1). Contrasted with rhizoma dioscoreae Raman spectra in the ranges of 600 to 800 cm(-1) and 1 000 to 1 400 cm(-1), the changes in rhizoma dioscoreae Raman first derivative spectra are represented more clearly than the rhizoma dioscoreae Raman spectra. So the rhizoma dioscoreae Raman first derivative spectra can be an accurate supplementary analysis method to the rhizoma dioscoreae Raman spectra.

[Two-photon excitation fluorescence of 5-ALA induced PpIX in DHL cells].

Two-photon fluorescence microscopy is a novel imaging technique, which is primarily sensitive to a specimen's response coming from an in-focus plane, thus has low photo-bleaching and photo-damage to biological samples. 5-ALA induced production of PpIX in DHL cells was excited by 820 nm femtosecond laser; two-photon excitation fluorescence of single cell was obtained in Lambda mode of laser scanning confocal microscope. The specific fluorescence intensity of PpIX which accumulated in DHL cells was measured at 2, 4 and 10 mmol x L(-1) concentration of 5-ALA with different incubation time, which reflected the kinetics of 5-ALA accumulated in DHL cells. Accumulation of PpIX in DHL cells was a dynamic change process. Biphasic alterations of PpIX accumulation were noted: PpIX content enhanced with the increasing time and reached the maximal value around 3 h, however PpIX content decreased in the subsequent incubation time. Results indicate that two-photon fluorescence based on laser scanning microscope can be a useful technology for studying the kinetics of 5-ALA induced PpIX production in DHL cells and other leukemia cells.

[Infrared spectrum analysis of admixture decoction of herba ephedrae with semen armeniacae amarum].

The infrared spectra of decoction of herba ephedra and semen armeniacae amarum and the mixed decoction of herba ephedra + semen armeniacae amarum were tested. The change in the the mixed decoction was discussed to study the relationship between herba ephedra and semen armeniacae amarum after decoction. The results showed that some absorption peaks of herba ephedra and semen armeniacae amarum were retained in the mixed decoction of herba ephedra + semen armeniacae amarum, such as 1402 and 1076 cm(-1), but some absorption peaks that never appear in the two ingredient spectra increased such as 1394 and 682 cm(-1). New absorption peaks were generated in the mixed decoction of herba ephedra + semen armeniacae amarum, such as 688 and 1187 cm(-1). It can be showed that there were differences in the chemistry environment of the various chemical groups in the three decoctions introduced above, with the variation in absorption peak position, and the biochemical structure of the material changed, possibly with some new chemical compositions created. Medical ingredients in the mixed decoction of herba ephedra + semen armeniacae amarum were not simply the addition of herba ephedra and semen armeniacae amarum based on studies of infrared spectrum of decoction, and the new notion of prescription spectroscopy was proposed.

[Spectral properties of the hemoporphyrin derivative interacting with hemoglobin].

The quenching reaction of hemoporphyrin derivative with hemoglobin (Hb) was studied by using fluorescence spectra and absorption spectra. It was shown that HpD has a powerful ability to quench the Hb fluorescence via a nonradiative energy transfer mechanism. The formation constants of them were analyzed at different temperature according to Stern-Volmer equation and double-reciprocal equation, which are bigger at high temperature than at low temperature. The critical binding site was calculated (R0 = 3.22 nm) by Föster energy transfer mechanism, and the thermodynamic parameters were obtained.