Characterization and classification of pathogenic bacteria using native fluorescence and spectral deconvolution.

Identification and classification of pathogenic bacterial strains is of current interest for the early treatment of diseases. In this work, protein fluorescence from eight different pathogenic bacterial strains were characterized using steady state and time resolved fluorescence spectroscopy. The spectral deconvolution method was also employed to decompose the emission contribution from different intrinsic fluorophores and extracted various key parameters, such as intensity, emission maxima, emission line width of the fluorophores, and optical redox ratio. The change in average lifetime values across different bacterial strains exhibits good statistical significance (p ≤ 0.01). The variations in the photophysical characteristics of bacterial strains are due to the different conformational states of the proteins. The stepwise multiple linear discriminate analysis of fluorescence emission spectra at 280 nm excitation across eight different bacterial strains classifies the original groups and cross validated group with 100% and 99.5% accuracy, respectively.

Chalcone derivatives' interaction with human serum albumin and cyclooxygenase-2.

Chalcone derivatives are an extremely valuable class of compounds, primarily due to the keto-ethylenic group, CO-CH[double bond, length as m-dash]CH-, they contain. Moreover, the presence of a reactive α,ß-unsaturated carbonyl group confers upon them a broad range of pharmacological properties. Recent developments in heterocyclic chemistry have led to the synthesis of chalcone derivatives, which have been biologically investigated for their activity against certain diseases. In this study, we investigated the binding of new chalcone derivatives with COX-2 (cyclooxygenase-2) and HSA (Human Serum Albumin) using spectroscopic and molecular modeling studies. COX-2 is commonly found in cancer and plays a role in the production of prostaglandin E (2), which can help tumors grow by binding to receptors. HSA is the most abundant protein in blood plasma, and it transports various compounds, including hormones and fatty acids. The conformation of chalcone derivatives in the HSA complex system was established through fluorescence steady and excited state spectroscopy techniques and FTIR analyses. To gain a more comprehensive understanding, molecular docking, and dynamics were conducted on the target protein (COX-2) and transport protein (HSA). In addition, we conducted density-functional theory (DFT) and single-point DFT to understand intermolecular interaction in protein active sites.

A biophysical approach of tyrphostin AG879 binding information in: bovine serum albumin, human ErbB2, c-RAF1 kinase, SARS-CoV-2 main protease and angiotensin-converting enzyme 2.

Viral infections cause significant health problems all over the world, and it is critical to develop treatments for these problems. Antivirals that target viral genome-encoded proteins frequently cause the virus to become more resistant to treatment. Because viruses rely on several cellular proteins and phosphorylation processes that are essential to their life cycle, drugs targeting host-based targets could be a viable treatment option. To reduce costs and improve efficiency, existing kinase inhibitors could be repurposed as antiviral medications; however, this method rarely works, and specific biophysical approaches are required in the field. Because of the widespread use of FDA-approved kinase inhibitors, it is now possible to better understand how host kinases contribute to viral infection. The purpose of this article is to investigate the tyrphostin AG879 (Tyrosine kinase inhibitor) binding information in Bovine Serum Albumin (BSA), human ErbB2 (HER2), C-RAF1 Kinase (c-RAF), SARS-CoV-2 main protease (COVID 19), and Angiotensin-converting enzyme 2 (ACE-2).Communicated by Ramaswamy H. Sarma.

Time-resolved emission spectroscopy to elucidate the functional nature of heat-stable transcription factor.

A 22 kDa protein from Thermus thermophilus is characterised as a DNA binding transcription regulator and its function is established using the fluorescence spectroscopy technique. The steady-state fluorescence spectroscopy result shows significant binding of calf thymus DNA and protein molecule. To confirm, the DNA quenching effect in real-time, a time-resolved emission spectroscopy study was performed and the result shows good agreement with steady-state quenching analysis.

Pulsed laser deposition of nanostructured bioactive glass and hydroxyapatite coatings: Microstructural and electrochemical characterization.

Bioactive coatings on metallic implants promote osseointegration between bone and implant interfaces. A suitable coating enhances the life span of the implant and reduces the requirement of revision surgery. The coating process needs to be optimized such that it does not alter the bioactivity of the material. To understand this, the biocompatibility of nanostructured bioactive glass and hydroxyapatite-coated Titanium substrate by pulsed laser deposition method is evaluated. Raman and IR spectroscopic techniques based on silica and phosphate functional groups mapping have confirmed homogeneity in coatings by pulse laser deposition method. Comparative studies on nanostructured bioactive glass and hydroxyapatite on titanium surface elaborated the significance of bioactivity, hemocompatibility, and cytocompatibility of the coated surface. Notably, both hydroxyapatite and bioactive glass show good hemocompatibility in powder form. Hemocompatibility and cytocompatibility results validate the enhanced sustenance for hydroxyapatite coating. These results signify the importance of the choice of coating methodology of bioceramics towards implant applications.

Green synthesis of white light emitting carbon quantum dots: Fabrication of white fluorescent film and optical sensor applications.

In this work, we have reported on the facile synthesis of white light-emitting carbon quantum dots (CQD) from corncob by hydrothermal method. This CQD has a broad emission from 380 nm to 650 nm with high photoluminescence intensity even after three months of shelf-life and stable at variable pH conditions. The presence of Si and N impurities in the biomass gives a greater advantage in producing white light emission with high quantum yield (54%) and enhanced lifetime at ambient conditions. The CQD is highly sensitive towards DNA, paracetamol, Pb2+, Cu2+, Fe3+, and Cr3+ fluorescence sensing and signifies its application as a multi-modal fluorescence sensor. The results of optical sensitivity calculated from the linear range of 1-10 ng/mL, 0.10-0.30 mg/mL, 2.5446 ng/mL, 0.0694 mg/mL, 0.3103-1.5515 µM/mL, 0.4299-4.7293 µM/mL, 1.3010 µM/mL and 0.05-2.5 µM/mL. The limit of detection is 2.5446 ng/mL, 0.0694 mg/mL, 0.8641 µM/mL, 1.2454 µM/mL, 1.3010 µM/m, 0.8550 µM/mL and 2.8562 µM/mL, respectively. And also, the relative standard deviation values of 2.30%, 4.46%, 1.79%, 1.84%, 0.26%, 1.23% and 0.35% are evidences its possibility of development towards potential optical sensor applications. Flexible white light-emitting sheets were fabricated from the CQD, illuminates uniform brightness, and has good color reproducibility and higher stability under various UV light excitation.

COVID-19: A promising cure for the global panic.

The novel Coronavirus disease 2019 (COVID-19) is caused by SARS-CoV-2, which is the causative agent of a potentially fatal disease that is of great global public health concern. The outbreak of COVID-19 is wreaking havoc worldwide due to inadequate risk assessment regarding the urgency of the situation. The COVID-19 pandemic has entered a dangerous new phase. When compared with SARS and MERS, COVID-19 has spread more rapidly, due to increased globalization and adaptation of the virus in every environment. Slowing the spread of the COVID-19 cases will significantly reduce the strain on the healthcare system of the country by limiting the number of people who are severely sick by COVID-19 and need hospital care. Hence, the recent outburst of COVID-19 highlights an urgent need for therapeutics targeting SARS-CoV-2. Here, we have discussed the structure of virus; varying symptoms among COVID-19, SARS, MERS and common flu; the probable mechanism behind the infection and its immune response. Further, the current treatment options, drugs available, ongoing trials and recent diagnostics for COVID-19 have been discussed. We suggest traditional Indian medicinal plants as possible novel therapeutic approaches, exclusively targeting SARS-CoV-2 and its pathways.

Enhanced Emission of Zinc Nitride Colloidal Nanoparticles with Organic Dyes for Optical Sensors and Imaging Application.

Herein, we have reported on the efficiency of inorganic Zn3N2 nanoparticles for labeling plant cells and animal cells toward imaging applications with negligible toxicity. We have synthesized zinc nitride (Zn3N2) colloidal nanoparticles with an average size of 25 nm at room temperature. The optical band gap of the prepared Zn3N2 nanoparticles is 2.8 eV and gives a visible range emission at 415 nm. With the addition of Zn3N2 colloids to organic dyes such as protoporphyrin, flavin adenine dinucleotide, fluorescein, and neutral red, the emission intensity of the organic dyes enhanced from 3 to 20 times. The molecular simulation and lifetime studies evidence the possibility of energy transfer from zinc nitride to organic dyes. The enhancement of dye intensity in the presence of Zn3N2 enhanced the vicinity of the cellular environment during confocal imaging of plant cells and animal cells. The detailed results suggested Zn3N2 for bioimaging and biosensor applications.

Synthesis and Characterization of Gd3+ Doped HfO2 Nanoparticles for Radiotherapy Applications.

Synthesis of pure Hafnium Oxide (HfO2), and HfO2 doped with Gadolinium (1, 3, 5 and 7 mol%) nanoparticles (NPs) had been carried out by Precipitation and co-precipitation method using the precursor solution of Hafnium (IV) chloride (HfCl4) and Gadolinium(III) chloride hexahydrate (GdCl3·6H2O) with Sodium hydroxide (NaOH) which was dissolved in deionized water. The synthesized compound was characterized and analyzed by X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), Energy dispersive X-ray analysis (EDX), UV-visible spectrophotometer, Photoluminescence (PL), Fourier Transform infrared spectroscopy (FTIR) and Raman spectroscopy. The result from X-ray diffraction showed that the Gd3+ concentration for 7 mol% had attended directly crystalline phase of Cubic HfO2 structure. Morphology and element analysis of the samples were analyzed using FESEM and EDX, which indicated cluster formation, fluffy and voids with highly agglomerated particles and EDX exhibited no extra peaks with other than constituent elements present in extrinsic HfO2. From UV Spectra it was observed that the optical band gap of both Intrinsic and extrinsic of HfO2 NPs were found to be 5.74 eV, 3.62 eV, 3.69 eV, 3.78 eV and 4.19 eV. The Photoluminescence Spectra showed the 313 nm emission line which might be due to 6P7/2→8S7/2 transition and the Raman Spectra clearly represented the monoclinic structure by showing the presence of Ag and Bg Modes and cubic structure because of the presence of F2g mode.

Monitoring Breast Cancer Response to Treatment Using Stokes Shift Spectroscopy of Blood Plasma.

With the emerging trend of personalized cancer treatment, there is a need to develop noninvasive/minimally invasive techniques for treatment monitoring. In this regard, in this work fluorescence analysis of blood plasma of breast cancer patients has been used for the evaluation of response to treatment. This approach delivers information not only about the change in biochemical constituents but also about the altered metabolic pathway. Spectral deconvolution method is employed to compute the fluorescence intensity, peak wavelength, and full-width half maxima for different endogenous fluorophores. The fluorescence measurements were made on blood plasma collected from 10 normal subjects, 10 pre-treated cancer patients, and 10 post-treated patients. Besides, variations in relative concentration of tryptophan, collagen, NADH, and FAD, peak shifts and broadening of peaks are observed for tryptophan, NADH, and FAD, in blood plasma of pre-treated cancer patients indicating both biochemical and microenvironmental changes at cellular level. Further, the spectral profile of blood plasma of post-treated patients found to be similar to blood plasma of normal subjects. Linear discriminant analysis showed that pre-treated and post-treated breast cancer is discriminated with a sensitivity and specificity of 100% and 100% respectively.

Exploring the Binding Interaction Mechanism of Taxol in ß-Tubulin and Bovine Serum Albumin: A Biophysical Approach.

In this present study on understanding the taxol (PTX) binding interaction mechanism in both the ß-tubulin and bovine serum albumin (BSA) molecule, various optical spectroscopy and computational techniques were used. The fluorescence steady-state emission spectroscopy result suggests that there is a static quenching mechanism of the PTX drug in both ß-tubulin and BSA, and further time-resolved emission spectroscopy studies confirm that the quenching mechanism exists. The excitation-emission matrix (EEM), Fourier transform infrared, and resonance light scattering spectra (FT-IR) confirm that there are structural changes in both the BSA and ß-tubulin molecule during the binding process of PTX. The molecular docking studies revealed the PTX binding information in BSA, ß-tubulin, and modeled ß-tubulin and the best binding pose to further subject the molecular dynamics simulation, and this study confirms the stability of PTX in the protein complex during the simulation. Density functional theory (DFT) calculations were performed between the free PTX drug and PTX drug (single point) in the protein molecule active site region to understand the internal stability.

Comparative Binding Analysis of N-Acetylneuraminic Acid in Bovine Serum Albumin and Human α-1 Acid Glycoprotein.

The present study focuses on the determination of the biologically significant N-acetylneuraminic acid (NANA) drug binding interaction mechanism between bovine serum albumin (BSA) and human α-1 acid glycoprotein (HAG) using various optical spectroscopy and computational methods. The steady state fluorescence spectroscopy result suggests that the fluorescence intensity of BSA and HAG was quenched by NANA in a static mode of quenching. Further time-resolved emission spectroscopy measurements confirm that mode of quenching mechanism of NANA in the BSA and HAG system. The FT-IR, excitation-emission matrix and circular dichroism (CD) analysis confirms the presence of NANA in the HAG, BSA system, and fluorescence resonance energy transfer analysis shows that NANA transfers energy between the HAG and BSA system. The molecular docking result shows good binding affinity in both protein complexes, and further molecular dynamics simulations and charge distribution analysis were performed to gain more insight into the binding interaction mechanism of NANA in the HAG and BSA complex.

A cytotoxicity, optical spectroscopy and computational binding analysis of 4-[3-acetyl-5-(acetylamino)-2-methyl-2,3-dihydro-1,3,4-thiadiazole-2-yl]phenyl benzoate in calf thymus DNA.

In this study the interaction mechanism between newly synthesized 4-(3-acetyl-5-(acetylamino)-2-methyl-2, 3-dihydro-1,3,4-thiadiazole-2-yl) phenyl benzoate (thiadiazole derivative) anticancer active drug with calf thymus DNA was investigated by using various optical spectroscopy techniques along with computational technique. The absorption spectrum shows a clear shift in the lower wavelength region, which may be due to strong hypochromic effect in the ctDNA and the drug. The results of steady state fluorescence spectroscopy show that there is static quenching occurring while increasing the thiadiazole drug concentration in the ethidium bromide-ctDNA system. Also the binding constant (K), thermo dynamical parameters of enthalpy change (ΔH°), entropy change (ΔS°) Gibbs free energy change (ΔG°) were calculated at different temperature (293 K, 298 K) and the results are in good agreement with theoretically calculated MMGBSA binding analysis. Time resolved emission spectroscopy analysis clearly explains the thiadiazole derivative competitive intercalation in the ethidium bromide-ctDNA system. Further, molecular docking studies was carried out to understand the hydrogen bonding and hydrophobic interaction between ctDNA and thiadiazole derivative molecule. In addition the docking and molecular dynamics charge distribution analysis was done to understand the internal stability of thiadiazole derivative drug binding sites of ctDNA. The global reactivity of thiadiazole derivative such as electronegativity, electrophilicity and chemical hardness has been calculated.

Near-infrared Raman spectroscopy for estimating biochemical changes associated with different pathological conditions of cervix.

The molecular level changes associated with oncogenesis precede the morphological changes in cells and tissues. Hence molecular level diagnosis would promote early diagnosis of the disease. Raman spectroscopy is capable of providing specific spectral signature of various biomolecules present in the cells and tissues under various pathological conditions. The aim of this work is to develop a non-linear multi-class statistical methodology for discrimination of normal, neoplastic and malignant cells/tissues. The tissues were classified as normal, pre-malignant and malignant by employing Principal Component Analysis followed by Artificial Neural Network (PC-ANN). The overall accuracy achieved was 99%. Further, to get an insight into the quantitative biochemical composition of the normal, neoplastic and malignant tissues, a linear combination of the major biochemicals by non-negative least squares technique was fit to the measured Raman spectra of the tissues. This technique confirms the changes in the major biomolecules such as lipids, nucleic acids, actin, glycogen and collagen associated with the different pathological conditions. To study the efficacy of this technique in comparison with histopathology, we have utilized Principal Component followed by Linear Discriminant Analysis (PC-LDA) to discriminate the well differentiated, moderately differentiated and poorly differentiated squamous cell carcinoma with an accuracy of 94.0%. And the results demonstrated that Raman spectroscopy has the potential to complement the good old technique of histopathology.

Determination on the binding of thiadiazole derivative to human serum albumin: a spectroscopy and computational approach.

4-[3-acetyl-5-(acetylamino)-2,3-dihydro-1,3,4-thiadiazole-2-yl]phenyl benzoate from the family of thiadiazole derivative has been newly synthesized. It has good anticancer activity as well as antibacterial and less toxic in nature, its binding characteristics are therefore of huge interest for understanding pharmacokinetic mechanism of the drug. The binding of thiadiazole derivative to human serum albumin (HSA) has been investigated by studying its quenching mechanism, binding kinetics and the molecular distance, r between the donor (HSA) and acceptor (thiadiazole derivative) was estimated according to Forster's theory of non-radiative energy transfer. The Gibbs free energy (ΔG), enthalpy (ΔH) and entropy (ΔS) changes of temperature-dependent Kb was calculated, which explains that the reaction is spontaneous and exothermic. The microenvironment of HSA have also been studied using synchronous fluorescence spectroscopy, and the feature of thiadiazole derivative-induced structural changes of HSA have been carried using Fourier transform infrared spectroscopy and the Molecular modelling simulations explore the hydrophobic and hydrogen bonding interactions.

High wavenumber Raman spectroscopy in the characterization of urinary metabolites of normal subjects, oral premalignant and malignant patients.

Urine has emerged as one of the diagnostically potential bio fluids, as it has many metabolites. As the concentration and the physiochemical properties of the urinary metabolites may vary under pathological transformation, Raman spectroscopic characterization of urine has been exploited as a significant tool in identifying several diseased conditions, including cancers. In the present study, an attempt was made to study the high wavenumber (HWVN) Raman spectroscopic characterization of urine samples of normal subjects, oral premalignant and malignant patients. It is concluded that the urinary metabolites flavoproteins, tryptophan and phenylalanine are responsible for the observed spectral variations between the normal and abnormal groups. Principal component analysis-based linear discriminant analysis was carried out to verify the diagnostic potentiality of the present technique. The discriminant analysis performed across normal and oral premalignant subjects classifies 95.6% of the original and 94.9% of the cross-validated grouped cases correctly. In the second analysis performed across normal and oral malignant groups, the accuracy of the original and cross-validated grouped cases was 96.4% and 92.1% respectively. Similarly, the third analysis performed across three groups, normal, oral premalignant and malignant groups, classifies 93.3% and 91.2% of the original and cross-validated grouped cases correctly.

Insights into the binding of thiosemicarbazone derivatives with human serum albumin: spectroscopy and molecular modelling studies.

4-[(1Z)-1-(2-carbamothioylhydrazinylidene)ethyl]phenyl acetate [Ace semi],4-[(1Z)-1-(2-carbamothioylhydrazinylidene)ethyl]phenyl propanoate [Pro semi] from the family of thiosemicarbazones derivative has been newly synthesized. It has good anticancer activity as well as antibacterial and it is also less toxic in nature, its binding characteristics are therefore of huge interest for understanding pharmacokinetic mechanism of the drug. The binding of thiosemicarbazone derivative to human serum albumin (HSA) has been investigated by studying its quenching mechanism, binding kinetics and the molecular distance (r) between donor (HSA) and acceptor (thiosemicarbazone derivative) was estimated according to Forster's theory of non-radiative energy transfer using fluorescence spectroscopy. The binding dynamics has been elaborated using synchronous fluorescence spectroscopy, and the feature of thiosemicarbazone derivative induced structural changes of HSA has been studied by circular dichorism, Fourier transform infrared spectroscopy. Molecular modelling simulations explore the hydrophobic interaction and hydrogen bonding which stabilizes the interaction.

Polarized Raman spectroscopy unravels the biomolecular structural changes in cervical cancer.

Polarized Raman spectroscopy has emerged as a promising technique giving a wealth of information about the orientation and symmetry of bond vibrations in addition to the general chemical information from the conventional Raman spectroscopy. In this regard, polarized Raman Spectroscopic technique was employed to study the changes in the orientation of biomolecules in normal and cancerous conditions. This technique was compared to the conventional Raman spectroscopic technique and was found to yield additional information about the orientation of tyrosine, collagen and DNA. The statistically analyzed depolarization ratios by Linear Discriminant Analysis yielded better accuracy than the statistical results of conventional Raman spectroscopy. Thus, this study reveals that polarized Raman spectroscopy has better diagnostic potential than the conventional Raman spectroscopic technique.

Native fluorescence spectroscopic characterization of DMBA induced carcinogenesis in mice skin for the early detection of tissue transformation.

The objective of the study is to characterize the endogenous porphyrin fluorescence in a dimethylbenz(a)anthracene (DMBA) induced mouse skin tumor model using native fluorescence emission and excitation spectroscopy. Two intensity ratio parameters I580/I635 and I420/I515 were selected to represent the key fluorophore of endogenous porphyrins from emission and excitation spectra recorded in vivo from 31 DMBA treated animals and 5 control animals. In the emission spectrum, the endogenous porphyrin was elevated at 635 nm in different transformation lesions such as hyperplasia, papilloma, dysplasia, ESCC and WDSCC. This is corroborated by the endogenous porphyrin elevation at 420, 515, 550 and 588 nm in the WDSCC lesions from the excitation spectra. The elevation of endogenous porphyrin, probably protoporphyrin IX (PpIX), is due to biochemical and metabolic alterations in epithelial cells during tissue transformation. The loss of ferrochelatase activity might be responsible for enhanced PpIX in the transformed tissues. The sensitivity and specificity were determined for different lesion pairs from the scatter plot based on the discrimination value by validation with histopathological results. The emission intensity ratio I580/I635 at 405 nm excitation was selected to discriminate normal from hyperplasia, hyperplasia from papilloma, papilloma from dysplasia, dysplasia from early squamous cell carcinoma (ESCC), and ESCC from well differentiated squamous cell carcinoma (WDSCC) with specificities of 100%, 88%, 100%, 86%, and 100% and sensitivities of 100%, 80%, 100%, 100% and 100% respectively. Similarly, the excitation intensity ratio I420/I515 for 635 nm emission used to discriminate between WDSCC lesions and normal tissue gives 100% specificity and 100% sensitivity.

Investigation of Optical Spectroscopic and Computational Binding Mode of Bovine Serum Albumin with 1, 4-Bis ((4-((4-Heptylpiperazin-1-yl) Methyl)-1H-1, 2, 3-Triazol-1-yl) Methyl) Benzene.

A newly synthesized 1, 4-bis ((4-((4-heptylpiperazin-1-yl) methyl)-1H-1, 2, 3-triazol-1-yl) methyl) benzene from the family of piperazine derivative has good anticancer activity, antibacterial and low toxic nature; its binding characteristics are therefore of huge interest for understanding pharmacokinetic mechanism of the drug. The binding of piperazine derivative to bovine serum albumin (BSA) was investigated using fluorescence spectroscopy. The molecular distance r between the donor (BSA) and acceptor (piperazine derivative) was estimated according to Forster's theory of nonradiative energy transfer. The physicochemical properties of piperazine derivative, which induced structural changes in BSA, have been studied by circular dichroism and those chemical environmental changes were probed using Raman spectroscopic analysis. Further, the binding dynamics was expounded by synchronous fluorescence spectroscopy and molecular modeling studies explored the hydrophobic interaction and hydrogen bonding results, which stabilize the interaction.