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Determination of liquid egg composition using ATR-FTIR spectroscopy and chemometrics
摘要： BACKGROUND: The use of liquid whole egg (LWE) in food industry as a substitute for shell eggs has been on the increase lately. Since the composition of LWE can easily be changed, determination of protein, lipid, moisture, and total soluble solid (TSS) contents of LWE has also gained importance. Traditional methods usually require more time and effort, and the use of toxic chemicals for sample preparation, where more efficient techniques (faster, cheaper, and more reliable) are needed. In this concern, a novel technique that determines LWE components using ATR-FTIR spectroscopy with partial least square regression (PLS) is presented in this study. RESULTS: The actual values of LWE components were detected by applying reference methods. The accuracy of PLS model was demonstrated by comparing the obtained predictions with the actual values of the component. High coefficients of determination values, which are 0.950, 0.992, 0.994, and 0.972, were achieved for protein, lipid, moisture, and TSS validation data sets, respectively. The error values, namely RMSEC, RMSECV, and RMSEP, were obtained in the range of 0.404-0.978, 0.57-1.82, and 0.83-1.84, respectively. CONCLUSION: ATR-FTIR spectroscopy coupled with chemometrics can provide a rapid and sensitive method for quality control of liquid egg composition.
关键词： chemometrics,composition,Liquid whole egg,ATR-FTIR spectroscopy,reference method
更新于2025-09-23 15:23:52
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Engineering organic electrochemical transistor (OECT) to be sensitive cell-based biosensor through tuning of channel area
摘要： The barrier integrity of epithelial tissue is crucial to many physiological functions in multicellular organisms. Hence, several scientific techniques, such as epithelial voltohmmeter (EVOM) and electric cell-substrate impedance sensing (ECIS), were developed to assess barrier function for in vitro assays. Organic electrochemical transistor (OECT), in particular, outperforms many biosensors because of its multiple advantages such as high transconductance, mixed ionic-electronic conductivity and high biocompatibility. Despite its extensive application in cell impedance sensing, little was reported on how its geometrical dimensions would affect the device performance and quality of cell-based measurement. In this work, OECTs in different dimensions were fabricated and characterized. Specifically investigated were their time and frequency responses towards the presence of epithelial cells (i.e. tightly packed colorectal adenocarcinoma cell line caco-2 and a novel leaky nasopharyngeal carcinoma cell line NPC43). Results show that the sensitivity of cell-based measurement is closely related to the impedance of the whole cell-OECT system. The performance of cell-based sensor would be affected by the tightness of target cell and can be tuned by controlling the active area of OECT.
关键词： Conducting polymer,Frequency response,Biosensor,Impedance spectroscopy,Transepithelial electrical resistance,Organic electrochemical transistor
更新于2025-09-23 15:23:52
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Spectral discrimination of planktonic cyanobacteria and microalgae based on deep UV fluorescence
摘要： The deep ultraviolet fluorescence characteristics of several cyanobacteria and microalgae are analyzed and exploited for their discrimination in liquid samples. The proposed approach is based on relative fluorescence peak amplitude of natural pigments in cyanobacteria or other planktonic species commonly present in water bodies. The experimental results demonstrate a clear discrimination between the various species of cyanobacteria and other planktonic species. This approach can be simply implemented in fluorescence measurement systems for real-time detection of cyanobacteria, provided that they are able to operate in deep ultraviolet.
关键词： Autofluorescence,Portable sensor,Cyanobacteria,Fluorescence spectroscopy
更新于2025-09-23 15:23:52
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An infrared IgG immunoassay based on the use of a nanocomposite consisting of silica coated Fe3O4 superparticles
摘要： A reliable, rapid and ultrasensitive immunoassay is described for determination of immunoglobulin G (IgG). It is making use of biofunctional magnetite (Fe3O4) superparticles coated with SiO2 and serving as an infrared (IR) probe. The unique IR fingerprint signals originating from the transverse and longitudinal phonon modes, respectively, of the asymmetric stretching of the Si–O–Si bridges display a satisfactory resistance to optical interference from the environment. The adoption of Fe3O4 superparticles instead of Fe3O4 nanoparticles as the magnetic core warrants a controllable structure and a strong magnetic response. This facilitates the efficient purification of the probes and the alleviation of the interfacial resistance between the liquid-solid interfaces by using a magnet. The gold-coated substrate was used to immobilize goat-anti-human IgG. The analyte (human IgG) was incubated with the IR probes, and then captured by the substrate immobilized antibody with the assistance of an external magnetic field. The integral area of the IR absorption band between 1250 cm?1 – 900 cm?1 was chosen for quantitative assay. The limit of detection is 95 fM, which is two orders of magnitude better than that without the magnetic field. The assay time was shortened from 2 h to 1 min. High selectivity, specificity, and long-term stability of the immunoassay were achieved. The performance of the assay when analyzing blood samples confirmed the practicability of the method.
关键词： Molecular vibration,IR spectroscopy,Core-shell,Sandwich immunoassay,Self-assembly,Protein,Blood,Superparamagnetism,Magnetic beads
更新于2025-09-23 15:23:52
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Transmission Low-Frequency Raman Spectroscopy for Quantification of Crystalline Polymorphs in Pharmaceutical Tablets
摘要： The purpose of this study was to quantify polymorphs of active pharmaceutical ingredients in pharmaceutical tablets using a novel transmission low-frequency Raman spectroscopy method. We developed a novel transmission geometry for low-frequency Raman spectroscopy and compared quantitative ability in transmission mode versus backscattering mode using chemometrics. We prepared two series of tablets: 1) containing different weight-based contents of carbamazepine form III and 2) including different ratios of carbamazepine polymorphs (forms I/ III). From the relationship between the contents of carbamazepine form III and partial least squares (PLS) predictions in the tablets, correlation coefficients in transmission mode (R2= 0.98) were found to be higher than in backscattering mode (R2= 0.97). The root mean square error of cross-validation (RMSECV) of the transmission mode was 3.9 compared to 4.9 for the backscattering mode. The tablets containing a mixture of carbamazepine (I/ III) polymorphs were measured by transmission low-frequency Raman spectroscopy, and it was found that the spectral shape changed according to the ratio of polymorphs: the relationship between the actual content and the prediction showed high correlation. These findings indicate that transmission low-frequency Raman spectroscopy possess the potential to complement existing analytical methods for the quantification of polymorphs.
关键词： Transmission,Carbamazepine,Pharmaceutical Tablets,Quantification,Low-Frequency Raman Spectroscopy,THz-Raman,Crystalline Polymorph
更新于2025-09-23 15:23:52
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5-aminolevulinic acid induced protoporphyrin IX (ALA-PpIX) fluorescence guidance in meningioma surgery
摘要： Introduction 5-aminolevulinic acid induced protoporphyrin IX (5-ALA-PpIX) fluorescence guidance has emerged as a valuable surgical adjunct for resection of intracranial tumors. Methods Here we present a focused review on 5-ALA-PpIX fluorescence guidance for meningiomas. Results We discuss the clinical studies and specific applications to date as well as the two main intraoperative fluorescence technologies applied to meningiomas. Conclusions The use of 5-ALA-PpIX in meningiomas holds promising potential so neurosurgeons can improve surgical outcomes for patients with meningiomas as well as be pioneers in developing improved fluorescence imaging technologies.
关键词： Meningioma,Quantitative fluorescence,5-Aminolevulinic acid,Fluorescence-guided surgery,Protoporphyrin IX,Spectroscopy
更新于2025-09-23 15:23:52
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Anisotropic Circular Dichroism of Light-Harvesting Complex II in Oriented Lipid Bilayers: Theory Meets Experiment
摘要： Anisotropic circular dichroism (ACD) spectroscopy of macroscopically aligned molecules reveals additional information about their excited states that is lost in the CD of randomly-oriented solutions. ACD spectra of light-harvesting complex II (LHCII)—the main peripheral antenna of photosystem II in plants—in oriented lipid bilayers, were recorded from the far-UV to the visible wavelength region. The ACD spectra show a drastically enhanced magnitude and level of detail compared to the isotropic CD spectra, resolving a greater number of bands and weak optical transitions. Exciton calculations show that the spectral features in the chlorophyll Qy region are well reproduced by an existing Hamiltonian for LHCII, providing further evidence for the identity of energy sinks at chlorophylls a603 and a610 in the stromal layer and chlorophylls a604 and a613 in the luminal layer. We propose ACD spectroscopy to be a valuable tool linking the three-dimensional structure and the photophysical properties of pigment–protein complexes.
关键词： optical spectroscopy,photosynthetic complexes,model membranes,oriented CD,excitonic CD,exciton theory
更新于2025-09-23 15:23:52
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Nondestructive Detection of Postharvest Quality of Cherry Tomatoes Using a Portable NIR Spectrometer and Chemometric Algorithms
摘要： The aim of this study was to assess the applicability of a portable NIR spectroscopy system and chemometric algorithms in intelligently detecting postharvest quality of cherry tomatoes. The postharvest quality of cherry tomatoes was evaluated in terms of firmness, soluble solids content (SSC), and pH, and a portable NIR spectrometer (950–1650 nm) was used to obtain the spectra of cherry tomatoes. Partial least square (PLS), support vector machine (SVM), and extreme learning machine (ELM) were applied to predict the postharvest quality of cherry tomatoes from their spectra. The effects of different preprocessing techniques, including Savitzky–Golay (S-G), multiplicative scattering correction (MSC), and standard normal variate (SNV) on prediction performance were also evaluated. Firmness, SSC and pH values of cherry tomatoes decreased during storage period, based on which the tomato samples could be classified into two distinct clusters. Similarly, cherry tomatoes with different storage time could also be separated by the NIR spectroscopic characteristics. The best prediction accuracy was obtained from ELM algorithms using the raw spectra with Rp2, RMSEP, and RPD values of 0.9666, 0.3141 N, and 5.6118 for firmness; 0.9179, 0.1485%, and 3.6249 for SSC; and 0.8519, 0.0164, and 2.7407 for pH, respectively. Excellent predictions for firmness and SSC (RPD value greater than 3.0), good prediction for pH (RPD value between 2.5 and 3.0) were obtained using ELM model. NIR spectroscopy is capable of intelligently detecting postharvest quality of cherry tomatoes during storage.
关键词： Partial least square,Extreme learning machine,Support vector machine,Cherry tomato,Near infrared spectroscopy
更新于2025-09-23 15:23:52
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Chiral Analysis || Quantitative Chiral Analysis by Molecular Rotational Spectroscopy
摘要： This chapter presents early results from the emerging field of quantitative chiral analysis by molecular rotational spectroscopy. The focus is on the development of measurement techniques to solve the challenging analytical chemistry problem of determining the ratios of all stereoisomers for a chiral molecule. This analysis becomes particularly challenging as the number of chiral centers in the molecule increases. Furthermore, this area of spectroscopy has the goal of creating measurement techniques that can be used directly on complex chemical mixtures to perform chiral analysis without the need of chemical separation by chromatography. Examples of chemical samples that fall into this category include natural products like essential oils from plants that are a rich mixture of volatile species and reaction flask samples where stereospecific chemical reactions are performed and which contain unreacted reagents, desired and undesired reaction products, and solvents in the mixture.
关键词： stereoisomers,chiral tag,diastereomers,molecular rotational spectroscopy,chirality,enantiomers,three-wave mixing,analytical chemistry,quantitative chiral analysis
更新于2025-09-23 15:23:52
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The Hollow Core Light cage: Trapping Light Behind Bars
摘要： Optical waveguides represent the key element of integrated planar photonic circuitry having revolutionized many fields of photonics ranging from telecommunications, medicine, environmental science and light generation. However, the use of solid cores imposes limitations on applications demanding strong light-matter interaction within low permittivity media such as gases or liquids, which has triggered substantial interest towards hollow core waveguides. Here, we introduce the concept of an on-chip hollow core light cage that consists of free standing arrays of cylindrical dielectric strands around a central hollow core implemented using 3D nanoprinting. The cage operates by an anti-resonant guidance effect and exhibits extraordinary properties such as (1) diffractionless propagation in “quasi-air” over more than a centimetre distance within the ultraviolet, visible and near-infrared spectral domains, (2) unique side-wise direct access to the hollow core via open spaces between the strands speeding up gas diffusion times by at least a factor of 104, and (3) an extraordinary high fraction of modal fields in the hollow section (> 99.9%). With these properties, the light cage can overcome the limitations of current planar hollow core waveguide technology, allowing unprecedented future on-chip applications within quantum technology, ultrafast spectroscopy, bioanalytics, acousto-optics, optofluidics and nonlinear optics.
关键词： integrated photonics,anti-resonance guidance,leaky modes,Hollow core waveguide,3D nanoprinting,spectroscopy
更新于2025-09-23 15:23:52