Dr. Vema Reddy Bheeram
@gitam.edu
Researcher, Nanoscience and Nanotechnology Laboratory, Department of Chemistry, Institute of Science
GITAM University
Dr. Vema Reddy Bheeram earned his BS degree from Osmania University in 2011 and MS degree in Analytical Chemistry from GITAM University in 2015. He completed his PhD study on Influence of gamma radiation on rare-earth doped luminescent nanophosphors at UGC-DAE-CSR, Kolkata and GITAM University in 2020 under the direction of Prof. M. Saratchandra Babu. Moreover, He was actively involved in the development of optical device and biomedical technologies, particularly based on nanotechnology innovations, for potential optoelectronic and biomedical applications.
EDUCATION
1. 2016 - 2020: Ph.D. in Chemistry, Department of Chemistry, GITAM University, India
2. 2013 - 2015: M.Sc in Analytical Chemistry, Department of Chemistry, GITAM University, India
3. 2008 - 2011: B.Sc in Chemistry, Osmania University, India
RESEARCH INTERESTS
Luminescence Nanomaterials, Lanthanide doped Upconversion Nanoparticles, Inorganic Materials, Coordination Chemistry, Lanthanide based Metal Organic Frameworks (Ln-MOFs), Optoelectronic Materials, Nanophotonics, X-ray crystallography, Biomedical Imaging, Drug delivery
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Scopus Publications
Vema Reddy Bheeram, Saratchandra Babu Mukkamala, Anima S. Dadhich, and Abhijit Saha
Elsevier BV
Abstract γ-radiation effect on structure, morphology and optical behaviour of GdVO4:RE3+/SiO2 (RE3+ = Er3+, Yb3+, Nd3+) nanophosphors has been evaluated. The synthesized products were examined by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM) and Photoluminescence spectra (PL). After photoexcitation of GdVO4:Er3+/SiO2, GdVO4:Yb3+/SiO2, GdVO4:Nd3+/SiO2 at 462, 487 and 532 nm, the respective rare-earth ions from phosphors emits red and NIR luminescence at 617 (2P3/2→ 4F9/2) and 690 nm (4F9/2→ 4I15/2); 640 (5F5/2→ 5I8/2) and 731 nm (5F4/2→ 5I7/2); 680 (4F9/2→ 4I9/2) and 798 nm (4F5/2→ 4I9/2). It was observed that the luminescence intensity had escalated on increasing the RE3+ content from 1 mol% to 5 mol%. Furthermore, after γ-irradiation at 150 and 300 kGy, the luminescence intensity had gone up 2–5 folds and 5–9 folds, respectively. On the other hand, the optical band gap was observed to have decreased with increasing luminescence intensity before and γ-irradiation. This enhanced red and NIR luminescence is very useful for LEDs, display and biomedical applications.
V.R. Bheeram, R.R. Malla, S. Kumari, A. Saha, and S.B. Mukkamala
Elsevier BV
Abstract Background Breast cancer reported in the young women exhibits high local and distant recurrence and a poor prognosis. Rare earth doped calcium phosphate phosphors have been extensively investigated due to their unique applications in biomedicine. Methods In the current study, Tb3+, Ce3+ doped Ca3(PO4)2 phosphor were prepared by hydrothermal method at 150 °C using citric acid as additive and characterized by PXRD, FT-IR, TG-DTA, EDX, TEM and PL techniques. The photoluminescence properties of Tb3+, Ce3+ doped Ca3(PO4)2 phosphor was investigated upon photo excitation at 240 nm. Antiproliferative activity was evaluated by MTT, BrdU proliferation, ELISA, Methylene blue and caspase-3 assays. Results Ca3(PO4)2:Tb3+, Ce3+ phosphor exhibited needle like morphology with length and width ∼100-500 nm and ∼40-50 nm, respectively. It exhibited green emission at 550 nm corresponding to 5D4→7F5 transition with the CIE coordinates (x, y) as (0.284, 0.614). It also showed remarkable concentration dependent cytotoxicity against MCF-7 as well as MDA-MB 231 cells with negligible cytotoxicity compared to MCF-12A, a human epithelial healthy cell line. It reduced the proliferative index of both cell lines in a concentration dependent manner by inhibiting DNA synthesis and Ki67 protein. It also induced distinct apoptotic changes in the morphology of cell and nucleus and also activated the caspase-3 activity in breast cancer cell lines. Conclusion The results suggest that Ca3(PO4)2:Tb3+, Ce3+ phosphor may be useful for therapeutic application in clinical settings.
Vema Reddy Bheeram, Anima S. Dadhich, Abhijit Saha, and Saratchandra Babu Mukkamala
Elsevier BV
Abstract The influence of gamma radiation on enhancement of red emission from Er3+ doped GdPO4@SiO2 nanophosphors was investigated. The luminescent emission was recorded after photoexcitation at 462 nm. The strong red luminescence at 690 nm corresponds to 4F9/2 → 4I15/2 transition. The luminescence intensity of the prepared phosphor had enhanced 2–4 folds and 4–6 fold after exposing to 150 kGy and 300 kGy gamma radiation, respectively. A linear response between luminescence intensity and irradiation dose was observed through PL dosimetry study. These biocompatible nanophosphors may have promising applications in biomedical and optoelectronic fields.
Satish Kumar Nandigama, Vema Reddy Bheeram, and Saratchandra Babu Mukkamala
Springer Science and Business Media LLC
Carbon dioxide (CO2) emissions from fossil fuels cause air pollution and lead to adverse impact on environment. To achieve low-carbon economy, capturing CO2 in the environment by methods like physisorption on zeolitic imidazolate frameworks (ZIFs) and other zeolite materials has gained attention due to their pore tunability and adsorption efficiency. Exploring the efficacy of the ZIF in adsorbing CO2, we report a rapid and convenient protocol for the synthesis of novel hybrid monometallic and bimetallic Zn/Co/Co–Zn-based ZIFs at room temperature, and we evaluate their CO2 capture capacity. ZIFs with varying Co:Zn ratio were synthesized by altering the content of Co and Zn precursors. The CO2 uptake capacity of mono/bimetallic Zn–Co ZIFs was studied at 298 K and attains the highest CO2 uptake of 65.50 cm3/g. This rapid room temperature protocol is highly efficient for the synthesis of mono/bimetallic ZIF-CO2 adsorbents.
Nandigama Satish Kumar, Marri Sameer Reddy, Vema Reddy Bheeram, Saratchandra Babu Mukkamala, L. Raju Chowhan, and L. Chandrasekhara Rao
Springer Science and Business Media LLC
Developing environmentally benign synthetic protocols such as reaction in water is a major challenge. However, many of the known methods carried out in an aqueous medium are not efficient at large scale and need purification involving volatile solvents. Heterogeneous catalysis by nanoparticles in aqueous medium is a possible solution. Therefore, we tested the use of heterogeneous zinc oxide nanoparticles to catalyse the synthesis of di-spiroindolizidine bisoxindoles at room temperature by three-component condensation in an aqueous medium via azomethine ylide-mediated 1,3-dipolar cycloaddition reaction. The products were obtained with regio- and diastereoselectivities, with yields ranging from 83 to 94%, in 60 min. Absolute structures of products were confirmed by single-crystal X-ray crystallography. A gram-scale reaction along with recyclability experiment of the heterogeneous catalyst was also performed. To establish the sustainability of the reaction presented, green chemistry matrixes were calculated and found to possess a high atom economy of 96.59% and small E-factor of 0.098. The presented method has advantages such as environmental friendly reaction conditions, use of inexpensive heterogeneous zinc oxide nanoparticle as catalyst, broad substrate scope, short reaction times, quantitative yields of complex di-spiroindolizidine bisoxindoles and absence of tedious purification procedure like column chromatography.
Vema Reddy Bheeram, Anima S. Dadhich, Radhakrishna Nagumantri, Satyanarayana Rentala, Abhijit Saha, and Saratchandra Babu Mukkamala
Elsevier BV
Abstract Near infrared (NIR) emitting nanophosphors have a great potential for biomedical applications. Core nanoparticles of Nd3+ doped GdPO4@SiO2 with 3–6 nm sized spheres have been synthesized by solution combustion synthesis. The structure, morphology and luminescence properties of as synthesized nanophosphors have been examined by X-ray diffraction, Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Photoluminescence spectra (PL). Upon photoexcitation at 532 nm, GdPO4:Nd3+@SiO2 emits red luminescence at 681 nm and NIR luminescence at 797 nm corresponding to 4F9/2 → 4I9/2 and 4F5/2 → 4I9/2 transitions, respectively. The luminescence intensity of nanophosphor had enhanced 2 folds on increasing the Nd3+ content from 1% to 5%. The luminescence intensity of these nanophosphors had further enhanced 2–3 folds and 8–10 folds after exposed to 150 kGy and 300 kGy of gamma radiation, respectively. In addition, this nanophosphor also exhibits high cytotoxicity against cell lines of PC-3 (Prostate cancer cells) and MCF-7 (Breast cancer cells).
Nandigama Satish Kumar, Marri Sameer Reddy, S. Tirumala Santosh Kumar, Vema Reddy Bheeram, Saratchandra Babu Mukkamala, and L. Chandrasekhara Rao
Wiley
Vema Reddy Bheeram, Anima S. Dadhich, Abhijit Saha, and Saratchandra Babu Mukkamala
Elsevier BV
Abstract The core/shell luminescent GdPO4:Yb3+@SiO2 nanophosphors have been synthesized via a facile solution combustion method. The effect of Yb3+ concentration and γ-radiation on the crystal phase, morphology and luminescent properties of nanophosphors has been studied. Upon photo excitation at 487 nm, GdPO4:Yb3+@SiO2 emits strong red luminescence at 640 nm and NIR luminescence at 731 nm corresponding to the 5F5 → 5I8 and 5F4 → 5I7 transitions, respectively. A 10-fold increase in luminescence intensity has been observed after increasing the Yb3+ content from 1% to 5%. Further, the Vis/NIR luminescence intensity of these nanophosphors had enhanced progressively 3–7 folds and 10–13 folds after exposed to 150 and 300 kGy γ-radiation, respectively. The dual advantage of Vis-NIR luminescence aided with biocompatibility makes these nanophosphors promising materials for biomedical applications.
Lenka Chandrasekhara Rao, Nandigama Satish Kumar, Vema Reddy Bheeram, Sadasivuni Hemambika, and Sarathchandra Babu Mukkamala
Wiley
Nandigama Satish Kumar, Vema Reddy Bheeram, Saratchandra Babu Mukkamala, L. Chandrasekhara Rao, and R. Vasantha
Wiley