Smart optical sensing of multiple antibiotic residues from wastewater effluents with ensured specificity using SERS assisted with multivariate analysis

Surface-enhanced Raman spectroscopy offers great potential for rapid and highly sensitive detection of pharmaceuticals from environmental sources. Herein, we investigated the feasibility of label-free sensing of antibiotic residues from wastewater effluents with high specificity by combining with multivariate analysis. Highly ordered silver nanoarrays with ∼34 nm roughness have been fabricated using a cost-effective electroless deposition technique. As-fabricated Ag arrays showed superior LSPR effects with an enhancement factor of 8 × 107. Excellent reproducibility has also been noticed with RSD values within 11%, whilst the sensor showed good stability and reusability characteristics for being used as a low-cost and reusable sensor. SERS studies demonstrated that antibiotics-spiked wastewater effluents can be detected with high efficiency in a label-free method. The molecular fingerprint bands of antibiotics such as sulfamethoxazole, sulfadiazine, and ciprofloxacin were well analyzed in effluent, tap, and deionized water. It has been found that antibiotics can be detected near picomolar levels; meanwhile, liquid chromatography-mass spectrometry (LC-MS) exhibited a detection limit within nanomolar concentrations only. Furthermore, the specificity of SERS sensing has been further analyzed using a multivariate analysis method, principal component analysis followed by linear discriminant analysis (PCA-LDA); which showed prominent discrimination to distinguish each antibiotic residue from wastewater effluents. The current study presented the potential of Ag nanoarray sensors for rapid, highly specific, and cost-effective analysis of pharmaceutical products for environmental remediation applications.

Infrared Spectroscopy for Rapid Triage of Cancer Using Blood Derivatives: A Reality Check

Infrared (IR) spectroscopy of serum/plasma represents an alluring molecular diagnostic tool, especially for cancer, as it can provide a molecular fingerprint of clinical samples based on vibrational modes of chemical bonds. However, despite the superior performance, the routine adoption of this technique for clinical settings has remained elusive. This is due to the potential confounding factors that are often overlooked and pose a significant barrier to clinical translation. In this Perspective, we summarize the concerns associated with various confounding factors, such as fluid sampling, optical effects, hemolysis, abnormal cardiovascular and/or hepatic functions, infections, alcoholism, diet style, age, and gender of a patient or normal control cohort, and improper selection of numerical methods that ultimately would lead to improper spectral diagnosis. We also propose some precautionary measures to overcome the challenges associated with these confounding factors.

Near infrared-emitting multimodal nanosystem for in vitro magnetic hyperthermia of hepatocellular carcinoma and dual imaging of in vivo liver fibrosis

Prolonged usage of traditional nanomaterials in the biological field has posed several short- and long-term toxicity issues. Over the past few years, smart nanomaterials (SNs) with controlled physical, chemical, and biological features have been synthesized in an effort to allay these challenges. The current study seeks to develop theranostic SNs based on iron oxide to enable simultaneous magnetic hyperthermia and magnetic resonance imaging (MRI), for chronic liver damage like liver fibrosis which is a major risk factor for hepatocellular carcinoma. To accomplish this, superparamagnetic iron oxide nanoparticles (SPIONs) were prepared, coated with a biocompatible and naturally occurring polysaccharide, alginate. The resultant material, ASPIONs were evaluated in terms of physicochemical, magnetic and biological properties. A hydrodynamic diameter of 40 nm and a transverse proton relaxation rate of 117.84 mM-1 s-1 pronounces the use of ASPIONs as an efficient MRI contrast agent. In the presence of alternating current of 300 A, ASPIONs could elevate the temperature to 45 °C or more, with the possibility of hyperthermia based therapeutic approach. Magnetic therapeutic and imaging potential of ASPIONs were further evaluated respectively in vitro and in vivo in HepG2 carcinoma cells and animal models of liver fibrosis, respectively. Finally, to introduce dual imaging capability along with magnetic properties, ASPIONs were conjugated with near infrared (NIR) dye Atto 700 and evaluated its optical imaging efficiency in animal model of liver fibrosis. Histological analysis further confirmed the liver targeting efficacy of the developed SNs for Magnetic theranostics and optical imaging as well as proved its short-term safety, in vivo.

Fluorescent carbon dots tailored iron oxide nano hybrid system forin vivooptical imaging of liver fibrosis

Hybrid nanoparticles are innovative invention of last decade designed to overcome limitations of single-component nanoparticles by introducing multiple functionalities through combining two or more different nanoparticles. In this study, we are reporting development of magneto-fluorescent hybrid nanoparticles by combining iron oxide and carbon nanoparticles to enablein vivofluorescence imaging which also has all the required characteristic properties to use as Magnetic Resonance Imaging (MRI) contrast agent. In order to achieve dual-functional imaging, alginate and pullulan coated super paramagnetic iron oxide nanoparticles (ASPION and PSPION) and Carbon dots (Cdts) were synthesised separately. ASPIONs and PSPIONs were further chemically conjugated with Cdts and developed dual-functional nanohybrid particles ASPION-Cdts and PSPION-Cdts. Subsequently, evaluation of the materials for its size, functionalisation efficiency, fluorescence and magnetic properties, biocompatibility and cellular uptake efficiency has been carried out. Fluorescence imaging of liver fibrosis was performedin vivoin rodent model of liver fibrosis using the two nanohybrids, which is further confirmed by high fluorescence signal from the harvested liver.

Autofluorescence spectroscopy and multivariate analysis for predicting the induced damages to other organs due to liver fibrosis

When our liver does not work well, it can induce damage to other organs causing their dysfunction. With this background, we aim to study the effect of liver fibrosis on other organs such as heart, lungs, kidney and spleen by assessing the variations in the inherent emission property of the tissue, using fluorescence spectroscopy. Fluorescence emission spectra from excised organs of liver fibrosis induced rats were collected at excitation wavelengths 320 and 410 nm. Optical redox ratio derived from the spectral data supported by multivariate statistical analysis, principal component analysis followed by linear discriminant analysis (PCA-LDA) distinguished between control and fibrosis induced groups. The two different excitation wavelength provided variations in the endogenous flurophores collagen, nicotinamide adenine dinucleotide (NADH), flavin adenine dinucleotide (FAD), lipopigments and porphyrins. Additionally, evaluation of redox ratio provided variations in tissue metabolic activity of different organs. The PCA-LDA modelling yielded a sensitivity of 85 to 97% and specificity of 80 to 96% on 320 nm excitation and a sensitivity of 72 to 100% and specificity of 59 to 100% on 410 nm excitation. Fluorescence emission spectral study along with multivariate analysis paved way to identify the biochemical alterations caused to other organs due to the development of liver fibrosis, which could lead to their damage and dysfunction.

Correction: Empirical study on the effects of acquisition parameters for FTIR hyperspectral imaging of brain tissue

Correction for 'Empirical study on the effects of acquisition parameters for FTIR hyperspectral imaging of brain tissue' by J. Sacharz et al., Anal. Methods, 2020, 12, 4334-4342, DOI: 10.1039/C9AY01200A.

Infrared Microspectroscopy With Multivariate Analysis to Differentiate Oral Hyperplasia From Squamous Cell Carcinoma: A Proof of Concept for Early Diagnosis

BACKGROUND AND OBJECTIVES

Despite having numerous advances in therapeutics, mortality and morbidity due to oral cancer incidence are still very high. Early detection can improve the chances of survival in most patients. However, diagnosis at early stages can be challenging as premalignant conditions are usually asymptomatic. Currently, histological assessment remains the gold standard for diagnosis. Early diagnosis poses challenges to pathologists due to less severe morphological changes associated with early stages. Therefore, a fast and robust method of detection based on molecular changes is needed for early diagnosis. © 2021 Wiley Periodicals LLC.

STUDY DESIGN/MATERIAL AND METHODS

In the present study, Fourier transform infrared (FTIR) spectroscopic imaging has been used to differentiate early-stage oral hyperplasia from adjacent normal (AN) and oral squamous cell carcinoma (OSCC). Hyperplasia is often considered as an initial event in the pathogenesis of oral cancer and OSCC is the most common advanced stage of malignancy. Differentiating normal versus hyperplasia and hyperplasia versus OSCC can remain quite challenging on occasion using conventional staining as the histological assessment is based on morphological changes.

RESULTS

Unsupervised hierarchical cluster analysis (UHCA) has been performed on FTIR images of multiple tissues together that provided some degree of classification among tissue groups. The AN epithelium clustered distinctively using UHCA from both hyperplasia and grades 1 and 2 of OSCC. An increase in the content of DNA, denaturation of protein, and altered lipid structures were more clearly elucidated with spectral analysis.

CONCLUSION

This study demonstrates a simple strategy to differentiate early-stage oral hyperplasia from AN and OSCC using UHCA. This study also proposes a future alternative method where FTIR imaging can be used as a diagnostic tool for cancer at early stages.

Optical diagnosis of oral lichen planus: A clinical study on the use of autofluorescence spectroscopy combined with multivariate analysis

Oral lichen planus (OLP) is a chronic mucocutaneous inflammatory condition of stratified squamous epithelia. OLP is a potentially malignant condition in oral mucosa. Patients with OLP have an increased risk of developing squamous cell carcinoma. Therefore an early and accurate diagnosis is necessary to avoid further damage to the oral mucosa. Biopsy followed by histopathological examination is the gold standard for the diagnosis of oral mucosal lesions including OLP. But this invasive procedure is traumatic and time consuming with limited statistical confidence level. Autofluorescence spectroscopy (AFS) has recently emerged as a potential tool to evaluate the biochemical changes associated with oral cavity disorders. In this study, we used AFS to differentiate the oral cavity tissue of 20 OLP patients from that of 16 normal volunteers. Spectra from oral mucosa were acquired at 280, 320 and 410 nm excitation wavelengths which correspond to the excitation energy of major endogenous fluorophores. Normalized spectral data at 320 nm excitation showed significant increase in the intensity of collagen peak for OLP. Optical redox ratio and total hemoglobin concentration estimated from the spectral data revealed significant increase and decrease respectively in OLP and normal patients. Principal component analysis followed by linear discriminant analysis (PCA-LDA) provided sensitivity and specificity of 71 and 80%, 80 and 90%, and 72 and 75% respectively for 280, 320 and 410 nm excited spectral datasets. Meanwhile, partial least square discriminant analysis (PLS-DA) provided sensitivity and specificity of 69 and 77%, 78 and 91% and 73 and 78.13% respectively for 280, 320 and 410 nm excited spectral datasets. From the results, it is concluded that AFS is an efficient tool for the non invasive diagnosis of OLP, with 320 nm light identified as the best wavelength for excitation.

Empirical study on the effects of acquisition parameters for FTIR hyperspectral imaging of brain tissue

Fourier transform infrared (FTIR) spectroscopic imaging is a powerful technique for molecular imaging of pathologies associated with the nervous systems including multiple sclerosis research. However, there is no standard methodology or standardized protocol for FTIR imaging of tissue sections that maximize the ability to discriminate between the molecular, white and granular layers, which is essential in the investigation of the mechanism of demyelination process. Tissue sections are heterogeneous, complex and delicate, hence the parameters to generate high quality images in minimal time becomes essential in the modern clinical laboratory. This article presents an FTIR spectroscopic imaging study of post-mortem human brain tissue testing the effects of various measurement parameters and data analysis methods on image quality and acquisition time. Hyperspectral images acquired from the same region of a tissue using a range of the most common optical and collection parameters in different combinations were compared. These included magnification (4× and 15×), number of co-added scans (1, 4, 8, 16, 32, 64 and 128 scans) and spectral resolution (4, 8 and 16 cm-1). Images were compared in terms of acquisition time, signal-to-noise (S/N) ratio, and accuracy of the discrimination between three major tissue types in a section from the cerebellum (white matter, granular and molecular layers). In the latter case, unsupervised k-means cluster (KMC) analysis was employed to generate images from the hyperspectral images, which were compared to a reference image. The classification accuracy for tissue class discrimination was highest for the 4× magnifying objective, with 4 cm-1 spectral resolution and 128 co-added scans. The 15× magnifying objective gave the best accuracy for a spectral resolution of 4 cm-1 and 64 scans (96.3%), which was just above what was achieved using the 4× magnifying objective, with 4 cm-1 spectral resolution and 32 and 64 co-added scans (95.4 and 95.6%, respectively). These findings were correlated with a decrease in S/N ratio with increasing number of scans and was generally lower for the 15× objective. However, longer scan times were required using the 15× magnifying objective, which did not justify the very small improvement in the classification of tissue types.

Infrared spectral microscopy as a tool to monitor lung fibrosis development in a model system

Tissue fibrosis is a progressive and destructive disease process that can occur in many different organs including the liver, kidney, skin, and lungs. Fibrosis is typically initiated by inflammation as a result of chronic insults such as infection, chemicals and autoimmune diseases. Current approaches to examine organ fibrosis are limited to radiological and histological analyses. Infrared spectroscopic imaging offers a potential alternative approach to gain insight into biochemical changes associated with fibrosis progression. In this study, we demonstrate that IR imaging of a mouse model of pulmonary fibrosis can identify biochemical changes observed with fibrosis progression and the beginning of resolution using K-means analysis, spectral ratios and multivariate data analysis. This study demonstrates that IR imaging may be a useful approach to understand the biochemical events associated with fibrosis initiation, progression and resolution for both the clinical setting and for assessing novel anti-fibrotic drugs in a model system.

Biosafety of citrate coated zerovalent iron nanoparticles for Magnetic Resonance Angiography

Though nanoparticles are being used for several biomedical applications, the safety of the same is still a concern. It is very routine procedure to check the preliminary safety aspects of the particles intended for in vivo applications. The major tests include how the material reacts to a normal cell, how it behaves with the blood cells and also whether any lysis take place in the presence of these materials. Here we present these test data of two novel nanomaterials designed for its use as contrast agent for magnetic resonance imaging and a multimodal contrast agent for targeted liver imaging. On proving the biosafety, the materials were tested for Magnetic Resonance Angiography using normal rats as model. The data of the same were clear identification of the prominent vascular structures and is included as the colour coded MRI image. Lateral and oblique view data are also presented for visualizing other major blood vessels.

Fluorescence spectroscopy as an efficient tool for staging the degree of liver fibrosis: an in vivo comparison with MRI

The study utilizes autofluorescence spectroscopy (AFS) along with multivariate spectral analysis for differentiating various stages of hepatic fibrosis. AFS has recently emerged as an efficient tool for evaluating the variations in different endogenous flurophores. In this study, the potential of AFS for differentiating the stages of liver fibrosis is assessed and compared with the results of enzyme evaluation, histopathology and the most advanced diagnostic tool, MRI. Using a fiber optic probe, the emission profile of the flurophores such as flavin adenine dinucleotide (FAD), lipofuscin-like lipopigments (lipopigments), porphyrins and the variation in the total hemoglobin concentration are evaluated in vivo on liver fibrosis induced animal models adopting a minimally invasive technique. Significant difference (p < 0.05) in the level of these biomarkers was observed between different stages of liver fibrosis. Normal hepatic tissue could be distinguished from mild and moderate hepatic fibrosis with a sensitivity of 95 to 100% and specificity of 90 to 100% using multivariate spectral analysis. The results are favourable to consider this technique as a potential tool for diagnosing liver fibrosis at an early stage, which is monumental as it otherwise can lead to cirrhosis and liver failure.

Infrared spectroscopic imaging: Label-free biochemical analysis of stroma and tissue fibrosis

Infrared spectroscopic tissue imaging is a potentially powerful adjunct tool to current histopathology techniques. By coupling the biochemical signature obtained through infrared spectroscopy to the spatial information offered by microscopy, this technique can selectively analyze the chemical composition of different features of unlabeled, unstained tissue sections. In the past, the tissue features that have received the most interest were parenchymal and epithelial cells, chiefly due to their involvement in dysplasia and progression to carcinoma; however, the field has recently turned its focus toward stroma and areas of fibrotic change. These components of tissue present an untapped source of biochemical information that can shed light on many diverse disease processes, and potentially hold useful predictive markers for these same pathologies. Here we review the recent applications of infrared spectroscopic imaging to stromal and fibrotic regions of diseased tissue, and explore the potential of this technique to advance current capabilities for tissue analysis.

Monitoring the biochemical alterations in hypertension affected salivary gland tissues using Fourier transform infrared hyperspectral imaging

FTIR imaging shows biochemical differences between salivary glands from control and hypertensive rats.

Multifunctional nano manganese ferrite ferrofluid for efficient theranostic application

Ferrofluid-based manganese (Mn(2+)) substituted superparamagnetic iron oxide nanoparticles stabilized by surface coating with trisodium citrate (MnIOTCs) were synthesized for enhanced hyperthermic activity and use as negative magnetic resonance imaging (MRI) contrast media intended for applications in theranostics. The synthesized MnIOTC materials were characterized based on their physicochemical and biological features. The crystal size and the particle size at the nano level were studied using XRD and TEM. The presence of citrate molecules on the crystal surface of the iron oxide was established by FTIR, TGA, DLS and zeta potential measurements. The superparamagnetic property of MnIOTCs was measured using a vibrating sample magnetometer. Superparamagnetic iron oxide substituted with Mn(2+) with a 3:1 molar concentration of Mn(2+) to Fe(2+) and surface modified with trisodium citrate (MnIO75TC) that exhibited a high T2 relaxivity of 184.6mM(-1)s(-1) and showed excellent signal intensity variation in vitro. Hyperthermia via application of an alternating magnetic field to MnIO75TC in a HeLa cell population induced apoptosis, which was further confirmed by FACS and cLSM observations. The morphological features of the cells were highly disrupted after the hyperthermia experiment, as evidenced from E-SEM images. Biocompatibility evaluation was performed using an alamar blue assay and hemolysis studies, and the results indicated good cytocompatibility and hemocompatibility for the synthesized particles. In the current study, the potential of MnIO75TC as a negative MRI contrast agent and a hyperthermia agent was demonstrated to confirm its utility in the burgeoning field of theranostics.

Fluorescence Imaging Assisted Photodynamic Therapy Using Photosensitizer-Linked Gold Quantum Clusters

Fluorescence imaging assisted photodynamic therapy (PDT) is a viable two-in-one clinical tool for cancer treatment and follow-up. While the surface plasmon effect of gold nanorods and nanoparticles has been effective for cancer therapy, their emission properties when compared to gold nanoclusters are weak for fluorescence imaging guided PDT. In order to address the above issues, we have synthesized a near-infrared-emitting gold quantum cluster capped with lipoic acid (L-AuC with (Au)18(L)14) based nanoplatform with excellent tumor reduction property by incorporating a tumor-targeting agent (folic acid) and a photosensitizer (protoporphyrin IX), for selective PDT. The synthesized quantum cluster based photosensitizer PFL-AuC showed 80% triplet quantum yield when compared to that of the photosensitizer alone (63%). PFL-AuC having 60 μg (0.136 mM) of protoporphyrin IX was sufficient to kill 50% of the tumor cell population. Effective destruction of tumor cells was evident from the histopathology and fluorescence imaging, which confirm the in vivo PDT efficacy of PFL-AuC.

Rapid and simple method of photobleaching to reduce background autofluorescence in lung tissue sections

Autofluorescence exhibited by tissues often interferes with immunofluorescence. Using imaging and spectral analysis, we observed remarkable reduction of autofluorescence of formalin fixed paraffin embedded tissues irradiated with light prior to incubation with immunofluorescent dyes. The technique of photobleaching offers significant improvement in the quality and specificity of immunofluorescence. This has the potential for better techniques for disease diagnosis.

Optical diagnosis of the progression and reversal of CCl4-induced liver injury in rodent model using minimally invasive autofluorescence spectroscopy

Schematic representation of the degree of intoxicant-induced liver injury and regeneration and the minimally invasive analysis using autofluorescence spectral features.

Noninvasive assessment of the risk of tobacco abuse in oral mucosa using fluorescence spectroscopy: a clinical approach

Tobacco abuse and alcoholism cause cancer, emphysema, and heart disease, which contribute to high death rates, globally. Society pays a significant cost for these habits whose first demonstration in many cases is in the oral cavity. Oral cavity disorders are highly curable if a screening procedure is available to diagnose them in the earliest stages. The aim of the study is to identify the severity of tobacco abuse, in oral cavity, as reflected by the emission from endogenous fluorophores and the chromophore hemoglobin. A group who had no tobacco habits and another with a history of tobacco abuse were included in this study. To compare the results with a pathological condition, a group of leukoplakia patients were also included. Emission from porphyrin and the spectral filtering modulation effect of hemoglobin were collected from different sites. Multivariate analysis strengthened the spectral features with a sensitivity of 60% to 100% and a specificity of 76% to 100% for the discrimination. Total hemoglobin and porphyrin levels of habitués and leukoplakia groups were comparable, indicating the alarming situation about the risk of tobacco abuse. Results prove that fluorescence spectroscopy along with multivariate analysis is an effective noninvasive tool for the early diagnosis of pathological changes due to tobacco abuse.

Synthesis and characterization of dextran stabilized superparamagnetic iron oxide nanoparticles for in vivo MR imaging of liver fibrosis

The field of medical imaging has recently seen rapid advances in the development of novel agents for enhancing image contrast. In particular, superparamagnetic iron oxide nanoparticles (SPIONs) with a variety of surface properties have been tried as effective contrast agents for magnetic resonance imaging, but with major side effects. In this study, the surface chemistry of SPIONs of size 12 nm was modified with high molecular weight dextran to yield particles of size 50 nm, without compromising the magnetic properties. A systematic characterization of the material for its size, coating efficiency, magnetic properties and biocompatibility has been carried out. The magnetic relaxivity as evaluated on a 1.5 T clinical magnet showed r2/r1 ratio of 56.28 which is higher than that reported for any other dextran stabilized ironoxide nanoparticles. Liver uptake and magnetic resonance imaging potential of dextran stabilized SPIONs (D-SPIONs) has been evaluated on liver fibrosis induced animal model, which is further supported by histopathology results.

Fluorescence spectroscopy as a highly potential single-entity tool to identify chromophores and fluorophores: study on neoplastic human brain lesions

Fluorescence and diffuse reflectance spectroscopy are powerful tools to differentiate normal and malignant tissue based on the emissions from endogenous fluorophores and diffuse reflection of absorbers such as hemoglobin. However, separate analytical methods are used for the identification of fluorophores and hemoglobin. The estimation of fluorophores and hemoglobin simultaneously using a single technique of autofluorescence spectroscopy is reported, and its diagnostic potential on clinical tissue samples is potentially exploited. Surgically removed brain tissues from patients that are later identified pathologically as astrocytoma, glioma, meningioma, and schwannoma are studied. The emissions from prominent fluorophores collagen, flavin adenine dinucleotide, phospholipids, and porphyrin are analyzed at 320 and 410 nm excitations. The hemoglobin concentration is also calculated from the ratio of fluorescence emissions at 500 and 570 nm. A better classification of normal and tumor tissues is yielded for 410 nm excitation compared to 320 nm when diagnostic algorithm based on linear discriminant analysis is used. The potential of fluorescence spectroscopy as a single entity to evaluate the prominent fluorophores as well as the hemoglobin concentration within normal and tumor brain tissues is emphasized.