Browsing by Author "Jayasree, RS"

Now showing 1 - 20 of 107
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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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    An insight into the optical properties of a sub nanosize glutathione stabilized gold cluster
    (DALTON TRANSACTIONS, 2016) Nair, LV; Nair, RV; Jayasree, RS
    In this study, gold quantum clusters with distinct fluorescence properties were developed and their structural and physical behaviour was evaluated. The clusters were prepared by etching gold nanoparticles with glutathione. Three different Au-33 clusters with emission profiles in the NIR region and one blue emitting cluster, Au-8 were developed by varying the geometrical arrangement of atoms within the cluster. These clusters having sizes in the range of 0.7 to 2 nm were synthesized by choosing different reaction temperatures from 0 degrees C to 70 degrees C and pH between 1.5 and 10. In the three cases, formation of self assembled atoms within the cluster and the corresponding changes in optical properties were observed. A detailed evaluation of the number of atoms and the core-ligand ratio using MALDI-MS and a change in the binding energy as seen in the XPS study confirmed this finding. The study demonstrates that the self assembly of atoms and their arrangement is an important factor in determining the characteristics of the cluster. In this communication, we put forward a new concept where the number of atoms and their arrangement within the clusters play a crucial role in tuning their optical properties.
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    An aqueous method for the controlled manganese (Mn2+) substitution in superparamagnetic iron oxide nanoparticle for contrast enhancement in MRI
    (Physical Chemistry Chemical Physics., 2015-01) Beerana, AE; Nazeerb, SS; Fernandezc, FB; Muvvala, KS; Wunderlich, W; Anil, S; Vellappally, S; Rao, R; John A, A; Jayasree, RS; Varma, HK
    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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    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, 2013-11) Venugopal, C; Nazeer, SS; Balan, A; Jayasree, RS
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    Autofluorescence spectroscopy for the in vivo evaluation of oral submucous fibrosis
    (Photomed Laser Surg., 2009) Haris, PS; Balan, A; Jayasree, RS; Gupta, AK
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    Bifunctional cysteine gold nanocluster for β-amyloid fibril inhibition and fluorescence imaging: A distinctive approach to manage Alzheimer's disease
    (Journal of Materials Chemistry B, 2023-04) Resmi, AN; Rekha, CR; Dhushyandhun, ME; Sarathkumar, E; Shenoy, SJ; Gulia, KK; Jayasree, RS
    Alzheimer's disease (AD) is a progressive complex neurodegenerative disorder affecting millions of individuals worldwide. Currently, there is no effective treatment for AD. AD is characterized by the deposition of amyloid plaques/fibrils. One major strategy for managing this disease is by slowing the progression of AD using different drugs which could potentially limit free-radical formation, oxidative stress and lipid peroxidation and promote the survival of neurons exposed to β-amyloid. Inhibition of amyloid fibrillization and clearance of amyloid plaques/fibrils are essential for the prevention and treatment of AD. The thiophilic interaction between the side chain of an aromatic residue in a polypeptide and a sulphur atom of the compound can effectively inhibit amyloid fibril formation. In this work, we have synthesized cysteine-capped gold nanoclusters (Cy-AuNCs) which exhibit inherent red emission and can disintegrate amyloid fibrils through the aforementioned thiophilic interactions. Herein, we also used molecular docking to study the thiophilic interactions between the sulphur atom of Cy-AuNCs and the aromatic rings of the protein. Finally, the gold cluster was functionalized with a brain targeting molecule, Levodopa (AuCs-LD), to specifically target the brain and to facilitate passage through the blood brain barrier (BBB). Both Cy-AuNCs and AuCs-LD showed good biocompatibility and the inherent fluorescence properties of nanoclusters enabled real time imaging. The efficacy of the nanoclusters to disintegrate amyloid fibrils and their ability to cross the BBB were demonstrated both in vitro and in vivo in the BBB model and the AD animal model respectively. Our results imply that nanoparticle-based artificial molecular chaperones may offer a promising therapeutic approach for AD.
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    Biocompatible InP/ZnSeS quantum dots/MXene composite as highly sensitive electrochemical sensors for carbendazim pesticide
    (Applied Surface Science, 2024-11) Sharma, TSK; Jana, J; Sivaselvam, S; Babu, B; Jayasree, RS; Mishra, Y; Hur, SH; Choi, WM
    In this study, we prepared InP/ZnSeS QDs anchored on MXene hybrid composite (IZQ-MX) for precise electrochemical sensing of carbendazim (CBZ) pesticide in food and environmental samples. The resulting electrochemical detection of CBZ exhibited a wide linear range of 0.019–527.6 μM, with a low detection limit of 14.59 nM and high sensitivity of 9.9026 µA·µM−1·cm−2. The environmental safety of IZQ-MX composite was further studied using in-vitro and in-vivo model. In L929 cells, exposure to IZQ-MX (0–100 nM) did not induce any significant change in cell viability, intracellular ROS generation and morphological changes. The exposure to IZQ-MX (0–200 nM) in C. elegans has also no significant change in primary and secondary endpoints of nematodes, neuronal development, DAF-16/FOXO and SKN-1/Nrf-2 transcription factors regulating the antioxidant genes. Environmental safety assessment of the IZQ-MX composite was performed using in-vitro and in-vivo models which demonstrated excellent biocompatibility. This work demonstrated the potential of IZQ-MX as significant electrocatalyst in sensitive and selective detection of CBZ for practical applications.
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    Bionanophotonics: general discussion. Faraday Discussion
    (Faraday Discussions, 2018-04) Chandra, A; Chattopadhyay, A; Cogdell, R; Datta, A; De, A; Dhamija, S; Golla, M; Haacke, S; Mahesh, H; Helliwell, J; Improta, R; Jayasree, RS
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    Blood brain barrier permeable gold nanocluster for targeted brain imaging and therapy: an in vitro and in vivo study.
    (Journal of Materials Chemistry, 2017-12) Nair, LV; Nair, RV; Shenoy, SJ; Thekkuveettil, A; Jayasree, RS
    Blood brain barrier (BBB) is a dynamic interface, comprising polarized endothelial cells, that separates the brain from the circulatory system. The highly protective nature of this tight junction impairs diagnosis and treatment of brain disorders. In this study, we designed a sub atomic size, near infrared emitting, dual function glutathione gold cluster with high fluorescence yield to facilitate permeability of BBB, for imaging applications and drug delivery. The gold cluster was then modified with Levodopa (L-dopa), to utilize the large amino acid transporter 1 (LAT1) pathways to enhance brain entry. Uptake and permeability of the nanoprobes were demonstrated using an established model of BBB, comprising brain endothelial cells (bEnd.3). The uptake and the clearance of L-dopa modified cluster was faster than the glutathione cluster. L-Dopa modified cluster supports the slow and sustained delivery of a model drug, pilocarpine, to the brain. Results of in vivo imaging and drug release in normal mice hold promise for considering the probe for early diagnosis of brain diseases, when the barrier is not disrupted, and for subsequent drug treatment.
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    Cadmium selenium quantum dot based nanosensor with femto molar level sensitivity for the detection of the pesticide endosulfan
    (Journal of Polymer Science and Engineering., 2024-01) Nair, LV; Nair. RV; Jayasree, RS
    Endosulfan (6,7,8,9,10,10-Hexachloro-1,5,5a,6,9,9a-hexahydro-6,9-methano-2,4,3-benzodioxathiepine-3-oxide) is an off-patent insecticide used in agricultural farms. Its usage as a pesticide has become highly controversial during the last decades. This is due to its reported hazardous nature to the health and side effects like growth retardation, hydrocephalus, and undesired changes in the male and female hormones leading to complications in sexual maturity. Endosulfan is the main culprit among all pesticide poisoning incidents around the world. Though the usage of this dreaded pesticide is banned by most countries, the high stability of this molecule to withstand degradation for a long period poses a threat to mankind even today. So, it has become highly essential to detect the presence of this poisonous pesticide in the drinking water and milk around these places. It is also advisable to check the presence of this toxic material in the blood of the population living in and around these places so that an early and appropriate management strategy can be adopted. With this aim, we have developed a sensor for endosulfan that displayed high selectivity and sensitivity among all other common analytes in water and biological samples, with a wide linear concentration range (2 fM to 2 mM), a low detection limit (2 fM), and rapid response. A citrate functionalized cadmium selenium quantum dot was used for this purpose, which showed a concentration-dependent fluorescence enhancement, enabling easy and sensitive sensing. This sensor was utilized to detect endosulfan in different sources of water, human blood serum and milk samples with good recoveries. It is also noted that the quantum dot forms a stable complex with endosulfan and is easy to separate it from the contaminated source, paving a solution for purifying the contaminated water. More detailed tests and validation of the sensor is needed to confirm these observations.
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    Cyclometalated Ir(III) complex as lysosome targeted photodynamic therapeutic agent for integrated imaging and therapy in cancer cells.
    (Chemistry - A European Journal, 2018-06) Sudheesh, KV; Jayaram, PS; Samanta, A; Kochan, S; Bejoymohandas, KS; Jayasree, RS; Ajayaghosh, A
    Organelle targeted photosensitizers (PSs) having luminescence properties are potential theranostic agents for simultaneous luminescence imaging and photodynamic therapy. Herein, we report a water soluble luminescent cyclometalated Ir(III) complex, Ir-Bp-Ly as lysosome targeted theranostic probe. Ir-Bp-Ly exhibits exceptional photophysical properties of good triplet state quantum yield (0.90), singlet oxygen generation quantum yield (0.71 at pH 4) and long lifetime (1.47 µs). Interestingly, Ir-Bp-Ly localized mostly in the lysosome because of the presence of morpholine units, suggesting its potential as a lyso-tracker. Ir-Bp-Ly displayed notable PDT effect in C6 glioma cells, as these PS efficiently generated ROS owing to the close proximity energy levels between triplet energy states of Ir-Bp-Ly and molecular oxygen (3O2). The mechanism of cell death was studied through caspase-3/7 and flow cytometry analysis that clearly established the apoptotic pathway.
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    Development of artificial skin (Template) and influence of different types of sterilization procedures on wound healing pattern in rabbits and guinea pigs
    (JOURNAL OF BIOMATERIALS APPLICATIONS, 1995)
    Different types of sterilization procedures have been applied onto artificial skin (Template) developed in our laboratory from polyetherurethane, chitosan and polyvinyl alcohol, etc Studies have been performed to investigate the differences in the wound healing pattern. It appears that quickened wound healing takes place in the rabbit model despite different types of samples and sterilization methods.
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    Doxorubicin-Polysorbate 80 conjugates: targeting effective and sustained delivery to the brain
    (RSC pharmaceutics, 2024-05) Ram Prasad, S; Leena, SS; Deepthi, A; Resmi, AN; Jayasree, RS; Sandhya, KS; Jayakrishnan, A
    Targeting therapeutic agents to the brain to treat the central nervous system (CNS) diseases is a major challenge due to the blood-brain-barrier (BBB). In this study, an attempt was made to deliver a model drug such as doxorubicin (DOX) to the brain in a mice model through DOX-Polysorbate 80 (DOX-PS80) conjugates. DOX was successfully conjugated with the non-ionic surfactant Polysorbate 80 (PS80) by carbamate linkage and the conjugate was characterized by different spectroscopic techniques such as FTIR, UV-Visible and NMR. The DOX conjugation efficacy was found to be 43.69 ± 4.72 %. The in vitro cumulative release of DOX from the conjugates was found to be 4.9 ± 0.8 % in PBS of pH 7.3 and 3.9 ± 0.6 % in simulated cerebrospinal fluid (CSF) of pH 7.3 at the end of 10 days. In vitro BBB permeability assay was carried out using bEnd.3 cells and DOX-PS80 conjugate showed a 3-fold increase in BBB permeability compared to controls. In vitro cytotoxicity assay using U251 human glioblastoma cells showed an IC50 value of 38.10 µg/mL for DOX-PS80. Cell uptake studies revealed that DOX-PS80 was effectively taken up (90%) by the bEnd.3 and U251 cells and localized in cytoplasm at the end of 24 h. Tumor spheroid assay and in vivo experiments in Swiss albino mice demonstrated the possibility of DOX-PS80 conjugate crossing the BBB and delivering the drug molecules to the target site for treating CNS disorders.
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    A dual signal on-off fluorescent nanosensor for the simultaneous detection of copper and creatinine
    (Materials Science and Engineering : C, 2019-12) Nair, RV; Parvathy, RS; Jayasree, RS
    The transition of conventional medicine to personalized medicine has paved the roadand need for the sensing of newer biomolecules. Hence, this area has attracted wide interestrecently, due to its capacity to provide information on point of care basis. Multi-analytedetection sensors have emerged recently as they can offer the opportunity to perform quickand affordable analysis with minimum blood sample, as compared to traditional sensing ofeach analytes individually. The present study focuses on the development of a quantum dot(Qd) based nanosensor for the simultaneous detection of copper and creatinine; twobiologically relevant molecules. The sensor was designed by forming a complex of Qd withEthyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) and picric acid through carboxylic bond formation of Qd-EDC with picric acid. The dual independent emissions of the Qd-EDCcomplex was used for the simultaneous detection of creatinine and copper by a turn on/turnoff method and was successfully demonstrated with a sensitivity of nanomolar to millimolar,and micromolar to millimolar range respectively. The multianalyte sensor thus developed hasquick response and works well under normal conditions of temperature and pH. It is alsoshown to work in cellular environment and blood serum. A mobile App based detection ofcreatinine using the developed sensor strips has also been attempted and validated withhuman blood samples
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    Effect of 980-nm diode laser and 1064-nm Nd:YAG laser on the intervertebral disc--in vitro and in vivo studies
    (Photomed Laser Surg., 2009) Jayasree, RS; Gupta, AK; Bodhey, NK; Mohanty, M
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    Effect of Photodynamic therapy on the chemically transformed tissue of mice
    (Toxicology International, 2004) Jayasree, RS; Gupta, AK; Mohanan, PV
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    Effect of substrate roughness on photoluminescence spectra of silicon nanocrystals grown by off axis pulsed laser deposition
    (Journal of Applied Physics, 2006) Rani, JR; Mahadevan Pillai, VP; Ajimsha, RS; Jayasraj, MK; Jayasree, RS