Browsing by Author "Nazeer, SS"

Now showing 1 - 20 of 34
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    An aqueous method for the controlled manganese (Mn2+) substitution in superparamagnetic iron oxide nanoparticles for contrast enhancement in MRI
    (PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 2015) Beeran, AE; Nazeer, SS; Fernandez, FB; Muvvala, KS; Wunderlich, W; Anil, S; Vellappally, S; Rao, MSR; John, A; Jayasree, RS; Varma, PRH
    Despite the success in the use of superparamagnetic iron oxide nanoparticles (SPION) for various scientific applications, its potential in biomedical fields has not been exploited to its full potential. In this context, an in situ substitution of Mn2+ was performed in SPION and a series of ferrite particles, MnxFe1-xFe2O4 with a varying molar ratio of Mn2+ : Fe2+ where 'x' varies from 0-0.75. The ferrite particles obtained were further studied in MRI contrast applications and showed appreciable enhancement in their MRI contrast properties. Manganese substituted ferrite nanocrystals (MnIOs) were synthesized using a novel, one-step aqueous co-precipitation method based on the use of a combination of sodium hydroxide and trisodium citrate (TSC). This approach yielded the formation of highly crystalline, superparamagnetic MnIOs with good control over their size and bivalent Mn ion crystal substitution. The presence of a TSC hydrophilic layer on the surface facilitated easy dispersion of the materials in an aqueous media. Primary characterizations such as structural, chemical and magnetic properties demonstrated the successful formation of manganese substituted ferrite. More significantly, the MRI relaxivity of the MnIOs improved fourfold when compared to SPION crystals imparting high potential for use as an MRI contrast agent. Further, the cytocompatibility and blood compatibility evaluations demonstrated excellent cell morphological integrity even at high concentrations of nanoparticles supporting the non-toxic nature of nanoparticles. These results open new horizons for the design of biocompatible water dispersible ferrite nanoparticles with good relaxivity properties via a versatile and easily scalable co-precipitation route.
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    Asialoglycoprotein receptor targeted optical and magnetic resonance imaging and therapy of liver fbrosis using pullulan stabilized multi-functional iron oxide nanoprobe
    (Scientific Reports., 2021-09) Saraswathy, A; Nazeer, SS; Nimi, N; Hema, S; Parvathy, RS; Jibin, K; Victor, M; Fernandez, FB; Sabareeswaran, A; Shenoy, SJ; Harikrishna Varma, PR; Jayasre, RS
    Early diagnosis and therapy of liver fibrosis is of utmost importance, especially considering the increased incidence of alcoholic and non-alcoholic liver syndromes. In this work, a systematic study is reported to develop a dual function and biocompatible nanoprobe for liver specific diagnostic and therapeutic applications. A polysaccharide polymer, pullulan stabilized iron oxide nanoparticle (P-SPIONs) enabled high liver specificity via asialogycoprotein receptor mediation. Longitudinal and transverse magnetic relaxation rates of 2.15 and 146.91 mM−1 s−1 respectively and a size of 12 nm, confirmed the T2 weighted magnetic resonance imaging (MRI) efficacy of P-SPIONs. A current of 400A on 5 mg/ml of P-SPIONs raised the temperature above 50 °C, to facilitate effective hyperthermia. Finally, a NIR dye conjugation facilitated targeted dual imaging in liver fibrosis models, in vivo, with favourable histopathological results and recommends its use in early stage diagnosis using MRI and optical imaging, and subsequent therapy using hyperthermia.
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    Autofluorescence spectroscopy and multivariate analysis for predictingthe induced damages to other organs due to liver fibrosis
    (Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2021-03) Nazeer, SS; Sreedevi, TP; Jayasree, RS
    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.
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    Autofluorescence Spectroscopy Augmented by Multivariate Analysis as a Potential Noninvasive Tool for Early Diagnosis of Oral Cavity Disorders
    (PHOTOMEDICINE AND LASER SURGERY, 2013) Venugopal, C; Nazeer, SS; Balan, A; Jayasree, R
    Objective: Oral leukoplakia is one of the common potentially malignant lesions encountered worldwide. We report the results of an in vivo clinical evaluation of autofluorescence (AF) spectroscopy for differential diagnosis of oral leukoplakia. Multivariate analysis of spectral data has been incorporated to improve the efficacy of the technique. The results of this noninvasive study are expected to provide potential for extending the technique to other disorders. Materials and methods: A total of 18 patients and 30 normal volunteers participated in this study. AF spectra were acquired from affected sites of patients and from right and left buccal mucosa of normal volunteers. Diagnostic performance was analyzed using spectral intensity ratio (SIR), and principal component analysis followed by linear discriminant analysis (PCA-LDA). Results: AF spectra of leukoplakic patients showed characteristic emissions from flavin adenine dinucleotide (FAD) and porphyrin at 500and 630nm, respectively. But the emission from porphyrin is not very prominent in the case of healthy volunteers. Also, significant decrease in spectral intensity is observed for leukoplakia compared with normal volunteers in the unprocessed spectra. Method of SIR yielded 96% sensitivity and 100% specificity and an overall 100% for PCA-LDA respectively for efficient differentiation of the lesions. Conclusions: The result of this preliminary study shows that PCA-LDA or SIR applied to AF spectroscopy is a useful tool for the differential diagnosis of oral cavity disorders. This has been demonstrated in leukoplakia in a clinical setting, and it is expected that the technique can be extended to other oral cavity disorders as well.
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    Autofluorescence Spectroscopy Augmented by Multivariate Analysis as a Potential Noninvasive Tool for Early Diagnosis of Oral Cavity Disorders.
    (Photomedicine and Laser Surgery, 2013-11) Venugopal, C; Nazeer, SS; Balan, A; Jayasree, RS
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    Endogenous porphyrin fluorescence as a biomarker for monitoring anti-angiogenic effect in antitumor response to hesperetin loaded nanoparticles in experimental oral carcinogenesis
    (RSC Advances, 2014-09) Krishnakumar, N; Gurushankar, K; Gohulkumar, M; Nazeer, SS; Jayasree, RS; Madhavan, NR
    The purpose of the present study is to evaluate the antitumor efficacy of hesperetin loaded nanoparticles (HETNPs) in comparison with native hesperetin (HET) for monitoring endogenous porphyrin emission against 7,12-dimethyl benz[a]anthracene (DMBA)-induced hamster buccal pouch carcinogenesis. The effort has been further complemented by immunohistochemical analysis in an attempt to provide a correlation between the emission intensity of endogenous porphyrin and changes in the vascular endothelial growth factor (VEGF) expression observed in control and the experimental animals. A total of 60 autofluorescence spectra were successfully acquired from different anatomic locations of the control and the experimental tissues. Significant differences in the autofluorescence spectral signatures between the control and that of experimental animals have been noticed under the excitation wavelength of 410 nm with emission ranging from 440–750 nm. DMBA-induced tumor tissues are associated with increased endogenous porphyrin emissions at 630 nm, 670 nm and 705 nm. Moreover, oral administration of HET and its nanoparticulates restored the status of endogenous porphyrin emission in the buccal mucosa of DMBA-painted animals. On a comparative basis, the treatment of nanoparticulate hesperetin was found to be more effective than native hesperetin in reducing the formation of squamous cell carcinoma and in improving the status of endogenous porphyrins to a near normal range in DMBA-induced hamster buccal pouch carcinogenesis. These endogenous porphyrin emissions may be used as a spectral biomarker for monitoring tumor hypervascularity. The hypervascularity in tumors might be due to angiogenesis. Complementary immunohistochemical analysis of the DMBA-induced tumor tissues showed an abundant expression of VEGF (a marker used for angiogenesis), suggesting that increased endogenous porphyrin intensities may be correlated with angiogenesis. Furthermore, the spectral data are also analyzed using a multivariate data analysis and yielded diagnostic sensitivities of 100%, 76.0%, 93.0% and 80.0% and specificities of 100%, 73.3%, 86.0% and 86.6%, respectively, for classification of control vs.DMBA, DMBA vs. DMBA + HET, DMBA vs. DMBA + HETNPs and DMBA + HET vs. DMBA + HETNPs treated tissues. The present study further suggests that endogenous porphyrin fluorescence could be considered as a reliable spectral marker and a very useful tool for monitoring the anti-angiogenic effect of cancer.
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    Endogenous porphyrin fluorescence as a biomarker for monitoring the anti-angiogenic effect in antitumor response to hesperetin loaded nanoparticles in experimental oral carcinogenesis
    (RSC ADVANCES, 2014) Gurushankar, K; Nazeer, SS; Gohulkumar, M; Jayasree, RS; Nirmal, MR; Krishnakumar, N
    The purpose of the present study is to evaluate the antitumor efficacy of hesperetin loaded nanoparticles (HETNPs) in comparison with native hesperetin (HET) for monitoring endogenous porphyrin emission against 7,12-dimethyl benz[a]anthracene (DMBA)-induced hamster buccal pouch carcinogenesis. The effort has been further complemented by immunohistochemical analysis in an attempt to provide a correlation between the emission intensity of endogenous porphyrin and changes in the vascular endothelial growth factor (VEGF) expression observed in control and the experimental animals. A total of 60 autofluorescence spectra were successfully acquired from different anatomic locations of the control and the experimental tissues. Significant differences in the autofluorescence spectral signatures between the control and that of experimental animals have been noticed under the excitation wavelength of 410 nm with emission ranging from 440-750 nm. DMBA-induced tumor tissues are associated with increased endogenous porphyrin emissions at similar to 630 nm, similar to 670 nm and similar to 705 nm. Moreover, oral administration of HET and its nanoparticulates restored the status of endogenous porphyrin emission in the buccal mucosa of DMBA-painted animals. On a comparative basis, the treatment of nanoparticulate hesperetin was found to be more effective than native hesperetin in reducing the formation of squamous cell carcinoma and in improving the status of endogenous porphyrins to a near normal range in DMBA-induced hamster buccal pouch carcinogenesis. These endogenous porphyrin emissions may be used as a spectral biomarker for monitoring tumor hypervascularity. The hypervascularity in tumors might be due to angiogenesis. Complementary immunohistochemical analysis of the DMBA-induced tumor tissues showed an abundant expression of VEGF (a marker used for angiogenesis), suggesting that increased endogenous porphyrin intensities may be correlated with angiogenesis. Furthermore, the spectral data are also analyzed using a multivariate data analysis and yielded diagnostic sensitivities of 100%, 76.0%, 93.0% and 80.0% and specificities of 100%, 73.3%, 86.0% and 86.6%, respectively, for classification of control vs. DMBA, DMBA vs. DMBA + HET, DMBA vs. DMBA + HETNPs and DMBA + HET vs. DMBA + HETNPs treated tissues. The present study further suggests that endogenous porphyrin fluorescence could be considered as a reliable spectral marker and a very useful tool for monitoring the anti-angiogenic effect of cancer.
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    Evaluation of Antitumor Activity of Hesperetin-Loaded Nanoparticles Against DMBA-Induced Oral Carcinogenesis Based on Tissue Autofluorescence Spectroscopy and Multivariate Analysis
    (J Fluoresc, 2015-06) Gurushankar, K; Nazeer, SS; Jayasree, RS; Krishnakumar, N
    The present study is designed to understand the nature of endogenous fluorophores and cellular metabolism that occur in the experimental oral carcinogenesis and to assess their feasibility for antitumor efficacy of hesperetinloaded nanoparticles (HETNPs) in comparison with native hesperetin (HET) against 7,12-dimethyl benz(a) anthracene (DMBA)-induced oral carcinogenesis using fluorescence spectroscopy. The fluorescence emission spectra of the control and the experimental buccal mucosa are recorded at an excitation wavelength of 320 nm with an emission ranging from 350 to 550 nm. The results show that there is a reduced contribution from the emission of collagen, nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FAD), inDMBA-induced tumor tissues as compared with the control tissues. Furthermore, there was significant decrease in the optical redox ratio [(FAD/ (NADH+FAD)] is observed in DMBA-induced tumor tissues, which indicates an increased metabolic activity when compared to the control tissues. Oral administration of HET and its nanoparticulates restored the status of endogenous fluorophores emission and would have a higher redox ratio in the buccal mucosa of DMBA painted animals. Taken together, the treatment of nanoparticulate hesperetin was found to be more effective than native hesperetin in improving the status of endogenous fluorophores to a near normal range in DMBA-induced hamster buccal pouch carcinogenesis. The results of this study raise the important possibility that fluorescence spectroscopy in conjunction with PC-LDA has tremendous potential for monitor or potentially predict response to therapy
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    Flower shaped assembly of cobalt ferrite nanoparticles: application as T-2 contrast agent in MRI
    (RSC ADVANCES, 2013) Nidhin, M; Nazeer, SS; Jayasree, RS; Kiran, MS; Nair, BU; Sreeram, KJ
    Material research has moved from generalization to specificity. Progress of nanoscience from synthesis to application oriented tailored synthesis has generated keen interest in the subject. The electrical and magnetic properties of spinel ferrites is one area of nanoscience that is slowing progress towards application oriented research. In this, CoFe2O4, owing to high magnetocrystalline anisotropy, high coercivity and low to moderate saturation magnetization, has found a variety of applications. Clusters of such nanoparticles are predicted to have revolutionary applications. Herein, we report the designed synthesis of cobalt ferrite clusters with a flower like morphology by employing a starch amylose-CTAB complex as a structure directing agent. The ability of starch amylose-CTAB to assemble nanoparticles from a centric core enabled the enhancement of the cluster diameter, leading to a ten fold increase in the T-2 relaxivity when compared to the nanoparticles. The nanoparticles were synthesized from metal-polysaccharide complexes, which led to a narrow particle size distribution, low polydispersity index and positively charged surface, all of which contributed to an enhanced R-2/R-1 value of 82.43, closer to several commercial products. Using starch as a template, along with a low concentration of CTAB, led to low cytotoxicity and high hemocompatibility. In addition, surface starch could provide easy uptake by stem cells and also be linked to light sensitive motifs for dynamic monitoring with MRI.
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    Fluorescence Imaging Assisted Photo dynamic Therapy Using Photosensitizer-Linked Gold Quantum Clusters
    (ACS NANO, 2015) Nair, LV; Nazeer, SS; Jayasree, RS; Ajayaghosh, A
    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 mu g (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.
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    Fluorescence spectroscopy as a highly potential single entity tool to identify chromophores and fluorophores: study on neoplastic human brain lesions
    (Journal of Biomedical Optics., 2013-06) Nazeer, SS; Ariya, Saraswathy; Gupta, AK; Jayasree, RS
    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.
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    Fluorescence spectroscopy as a highly potential single-entity tool to identify chromophores and fluorophores: study on neoplastic human brain lesions
    (JOURNAL OF BIOMEDICAL OPTICS, 2013) Nazeer, SS; Saraswathy, A; Gupta, AK; Jayasree, RS
    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. (C) 2013 Society of Photo-Optical Instrumentation Engineers (SPIE)
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    Fluorescence spectroscopy as an efficient tool for staging the degree of liver fibrosis: an in vivo comparison with MRI
    (Sci Rep. 2018, 2018-07) Nazeer, SS; Saraswathy, A; Shenoy, SJ; Jayasree, RS
    The study utilizes autofuorescence spectroscopy (AFS) along with multivariate spectral analysis for diferentiating various stages of hepatic fbrosis. AFS has recently emerged as an efcient tool for evaluating the variations in diferent endogenous furophores. In this study, the potential of AFS for diferentiating the stages of liver fbrosis is assessed and compared with the results of enzyme evaluation, histopathology and the most advanced diagnostic tool, MRI. Using a fber optic probe, the emission profle of the furophores such as favin adenine dinucleotide (FAD), lipofuscin-like lipopigments (lipopigments), porphyrins and the variation in the total hemoglobin concentration are evaluated in vivo on liver fbrosis induced animal models adopting a minimally invasive technique. Signifcant diference (p<0.05) in the level of these biomarkers was observed between diferent stages of liver fbrosis. Normal hepatic tissue could be distinguished from mild and moderate hepatic fbrosis with a sensitivity of 95 to 100% and specifcity of 90 to 100% using multivariate spectral analysis. The results are favourable to consider this technique as a potential tool for diagnosing liver fbrosis at an early stage, which is monumental as it otherwise can lead to cirrhosis and liver failure.
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    Fluorescence spectroscopy to discriminate neoplastic human brain lesions: a study using the spectral intensity ratio and multivariate linear discriminant analysis
    (LASER PHYSICS, 2014) Nazeer, SS; Saraswathy, A; Gupta, AK; Jayasree, RS
    Fluorescence spectroscopy is an emerging tool used to differentiate normal and malignant tissue based on the emission spectral profile from endogenous fluorophores. The goal of this study is to estimate the concentration of fluorophores using autofluorescence spectroscopy and try to utilize its diagnostic potential on samples of clinical importance. Brain tumor tissues from patients who received craniotomy for the removal of astrocytoma, glioma, meningioma and schwannoma were utilized in this study. Fluorescence emissions of the formalin fixed samples were recorded at excitation wavelengths of 320 and 410 nm. The emission characteristics of fluorophores such as collagen, nicotinamide adenine dinucleotide (NADH), flavin adenine dinucleotide (FAD), phospholipids and porphyrins of tumor tissue and adjacent normal tissue were elicited. Exact tissue classification was carried out using the spectral intensity ratio (SIR) and multivariate principal component analysis-linear discriminant analysis (PCA-LDA). The diagnostic algorithm based on PCA-LDA provided better classification efficiency than SIR. Moreover, the spectral data based on an excitation wavelength of 410 nm are found to be more efficient in the classification than 320 nm excitation, using PCA-LDA. Better efficacy of PCA-LDA in tissue classification was further confirmed by the receiver operator characteristic (ROC) curve method. The results of this study establish the feasibility of using fluorescence spectroscopy based real time tools for the discrimination of brain tumors from the adjacent normal tissue during craniotomies, which at present faces a huge challenge.
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    Fluorescence spectroscopy to discriminate neoplastic human brain lesions: a study using the spectral intensity ratio and multivariate linear discriminant analysis.
    (Laser Physics., 2014-01) Nazeer, SS; Saraswathy, A; Gupta, AK; Jayasree, RS
    Fluorescence spectroscopy is an emerging tool used to differentiate normal and malignant tissue based on the emission spectral profile from endogenous fluorophores. The goal of this study is to estimate the concentration of fluorophores using autofluorescence spectroscopy and try to utilize its diagnostic potential on samples of clinical importance. Brain tumor tissues from patients who received craniotomy for the removal of astrocytoma, glioma, meningioma and schwannoma were utilized in this study. Fluorescence emissions of the formalin fixed samples were recorded at excitation wavelengths of 320 and 410 nm. The emission characteristics of fluorophores such as collagen, nicotinamide adenine dinucleotide (NADH), flavin adenine dinucleotide (FAD), phospholipids and porphyrins of tumor tissue and adjacent normal tissue were elicited. Exact tissue classification was carried out using the spectral intensity ratio (SIR) and multivariate principal component analysis–linear discriminant analysis (PCA–LDA). The diagnostic algorithm based on PCA–LDA provided better classification efficiency than SIR. Moreover, the spectral data based on an excitation wavelength of 410 nm are found to be more efficient in the classification than 320 nm excitation, using PCA–LDA. Better efficacy of PCA–LDA in tissue classification was further confirmed by the receiver operator characteristic (ROC) curve method. The results of this study establish the feasibility of using fluorescence spectroscopy based real time tools for the discrimination of brain tumors from the adjacent normal tissue during craniotomies, which at present faces a huge challenge.
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    Fluorescent carbon dots tailored iron oxide nano hybrid system for in vivo optical imaging of liver fibrosis
    (Methods and Applications in Fluorescence, 2023-03) Nazeer, SS; Saraswathy, A; Nimi, N; Sarathkumar, E; Resmi, AN; Shenoy, SJ; Jayasree, RS
    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.
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    Forensic application of fluorescence spectroscopy: An efficient technique to predict the presence of human saliva
    (Journal of Luminescence, 2018-11) Denny, SE; Nazeer, SS; Sivakumar, TT; Nair, BJ; Jayasree, RS
    In this study, we aim to use the fluorescence spectroscopic data as a preliminary forensic evidence for the detection of saliva stains from the surface of drinking glass, to see the potential of utilizing a comparatively simple method to trace the presence of saliva from inanimate objects such as cigars, papers, cloths and envelopes. Since dried stains of saliva are invisible to human eyes, detection of saliva from such sources is a challenge in forensic analysis. The fluorescence emission spectra of dried saliva samples collected from drinking glass were compared to that of undiluted liquid saliva of the same volunteers. The deposition of saliva was predicted based on the emission spectra of the enzyme amylase around 350 nm, which is present in high concentrations in saliva. The dried saliva stains and undiluted liquid saliva showed an emission peak at 350 ± 5 nm and 345 ± 5 nm, respectively. The fluorescence emission spectra obtained from the dried saliva samples confirmed well to those of undiluted liquid saliva and amylase.The fluorescence intensity and area underneath the fluorescence peak of undiluted liquid saliva as well as dried saliva were also studied. The study concludes that by correlating fluorescence emission peak, fluorescence intensity and area under the curve, saliva can be detected from dried stains. The potential of fluorescence spectroscopy is also emphasised to detect the presence of saliva from inanimate objects like that of drinking glass, by identifying the emission peak of amylase, one of the prominent saliva components. Thus by using this simple technique, the best possible samples for a detailed DNA analysis may be screened and selected, which could significantly contribute to forensic identification.
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    Influence of Tissue Fluorescence Measurement and Imaging by Auto-Fluorescence of Substrata
    (JOURNAL OF APPLIED SPECTROSCOPY, 2015) Kumar, BS; Sandhyamani, S; Nazeer, SS; Jayasree, RS
    Polymers, glass and fiber reinforced materials are increasingly being used in photophysical devices. The inherent fluorescence of devices made of these materials may itself become important during fluorescence detection. It may interfere with or even negate the low fluorescence signals emitted from fluorophores molecules of interest especially when the fluorophores exist in microvolume samples. Such effects are significant when tissue micro-sections placed on substrata of high background fluorescence. Using different excitation wavelengths, fluorescence spectral and imaging studies were carried out to examine the effect of background fluorescence of microslides made of various substrata such as glass, polycarbonate and aluminium on autofluorescence of tissue sections. With decreasing wavelength of excitation, all substrata showed increased autofluorescence. Glass showed least inherent fluorescence and aluminium showed more reflectance than autofluorescence. After continuous exposure to blue and UV light, all substrata showed irreversible decreased autofluorescence. During spectrofluorimetric studies, a definite blue shift was observed in the autofluorescence of tissue sections placed on microslides made of each of the materials. This suggests an interference of tissue autofluorescence by background fluorescence emitted by the substratum. This may lead to false positive or negative reporting of the fluorophores, particularly important while analyzing micro-sections of biological samples. Microscopic imaging did not show any background fluorescence for glass substratum with blue light. However, with UV light, glass also showed background fluorescence during imaging. Other substrata showed strong background fluorescence or reflectance with both blue and UV light. This study has the potential for accurate quantification of fluorescence spectral and decay and improved fluorescence imaging using the photobleaching effect.
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    Influence of tissue fluorescence measurement and imaging by autofluorescence of substrata
    (Journal of Applied Spectroscopy, 2015-08) Santhosh Kumar, B; Sandhyamani, S; Nazeer, SS; Jayasree, RS
    Polymers, glass and fi ber reinforced materials are increasingly being used in photophysical devices. The inherent fl uorescence of devices made of these materials may itself become important during fl uorescence detection. It may interfere with or even negate the low fl uorescence signals emitted from fl uorophores molecules of interest especially when the fl uorophores exist in microvolume samples. Such effects are signifi cant when tissue micro-sections placed on substrata of high background fl uorescence. Using different excitation wavelengths, fl uorescence spectral and imaging studies were carried out to examine the effect of background fl uorescence of microslides made of various substrata such as glass, polycarbonate and aluminium on autofl uorescence of tissue sections. With decreasing wavelength of excitation, all substrata showed increased autofl uorescence. Glass showed least inherent fl uorescence and aluminium showed more refl ectance than autofl uorescence. After continuous exposure to blue and UV light, all substrata showed irreversible decreased autofl uorescence. During spectrofl uorimetric studies, a defi nite blue shift was observed in the autofl uorescence of tissue sections placed on microslides made of each of the materials. This suggests an interference of tissue autofl uorescence by background fl uorescence emitted by the substratum. This may lead to false positive or negative reporting of the fl uorophores, particularly important while analyzing micro-sections of biological samples. Microscopic imaging did not show any background fl uorescence for glass substratum with blue light. However, with UV light, glass also showed background fl uorescence during imaging. Other substrata showed strong background fl uorescence or refl ectance with both blue and UV light. This study has the potential for accurate quantifi cation of fl uorescence spectral and decay and improved fl uorescence imaging using the photobleaching effect.
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    Infrared Spectroscopy for Rapid Triage of Cancer Using Blood Derivatives: A Reality Check
    (Anal Chem., 2024-01) Nazeer, SS; Venkataraman, RK; Jayasree, RS; Bayry, J
    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.