Browsing by Author "Vivek Kumar Verma"

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Bright fluorescent biocompatible Magnozyme nanoclusters for brain-cell in-vivo live imaging
(Elsevier B.V., 2025) Prachi Srivastava; Vivek Kumar Verma; Abhishesh Kumar Mehata; Mamata K. Singh; Shivesh Sabbarwal; Madaswamy Sona S Muthu; Biplob Koch; Manoj Kumar
Multifluorescent, water-dispersible magnesium nanoclusters (Magnozyme) were obtained using a simple and economical synthesis procedure. The prepared particles were 4 nm in size, and they exhibited significant emission at 450, 545, and 628 nm with multiple excitations of 366,469 and 560 nm wavelengths. The prepared particle exhibited a maximum absolute quantum yield of 21.3, 6.8 % and 5 % in red, green and blue spectrum, respectively, with excellent photostability, good ionic strength tolerability, and broad-range pH stability. The prepared Magnozyme demonstrates 95 % cell viability in human glioma brain cell lines (U-87 MG) and can be used as a probe for cellular imaging. Furthermore, imaging with this brain cell revealed significant cytoplasmic accumulation in the red, green, and blue regions. The confocal Z-stack study revealed the presence of Magnozyme at a depth of the cellular level by capturing a series of images at different planer axes (z-axis). Furthermore, In-vivo toxicity assessments and in-vivo imaging in mice revealed the nontoxicity behavior of Magnozyme with their great staining ability in physiological conditions, confirming their candidature toward biological cell imaging/labeling purposes. © 2025 Elsevier B.V.
Fluorescent Calcium Nanocluster-Driven Theranostic Nanoplatforms for Advanced Imaging and Therapy in Breast Tumor
(American Chemical Society, 2025) Abhishesh Kumar Mehata; Vivek Kumar Verma; Virendra Pratap Singh; Aseem Setia; None Vikas; Matte Kasi Viswanadh; Shivesh Sabbarwal; Manoj Kumar; Biplob Koch; Madaswamy Sona S Muthu
Biocompatible CaCO3 nanoclusters were prepared by using a simple biomineralization technique. Employing CaCO3 nanoclusters in breast cancer treatment provides an exciting avenue for theranostics, which merges precise imaging with individualized treatment plans. They were highly suitable for improving the efficacy and precision of breast cancer detection and therapy with minimal adverse effects due to their biocompatibility, controlled drug release, pH sensitivity, and adaptability. In our current study, we proposed a palbociclib (PBB)-loaded fluorescent calcium nanocluster-based redox-sensitive drug delivery system for efficient breast cancer imaging and therapy. The developed nanoparticles were analyzed for their morphology and various physicochemical properties. The particle sizes of the formulated FNC-PBB-CS-NPs (nonredox-sensitive) and FNC-PBB-CS-SS-NPs (redox-sensitive) nanoparticles were 150.2 ± 2.1 and 160.4 ± 1.4 nm, respectively. The zeta potential of nonredox-sensitive nanoparticles was measured to be +17.12 ± 1.34 mV, while the zeta potential of redox-sensitive nanoparticles was +14.32 ± 1.17 mV. The entrapment efficiencies of FNC-PBB-CS-NPs and FNC-PBB-CS-SS-NPs were determined to be 88.74 ± 2.34 and 89.26 ± 1.21%, respectively. FNC-PBB-CS-SS-NPs demonstrated quicker drug release at acidic pH compared to FNC-PBB-CS-NPs. The cytotoxicity assay conducted on MCF-7 and T-47D cells indicated that FNC-PBB-CS-NPs and FNC-PBB-CS-SS-NPs exhibited greater cytotoxicities than free PBB. Furthermore, the Hoechst/PI dual-staining experiment demonstrated the superior activity of FNC-PBB-CS-SS-NPs over FNC-PBB-CS-NPs and free PBB. Ultrasound/photoacoustic imaging revealed that FNC-PBB-CS-SS-NPs effectively reduced tumor size, hypoxic tumor regions, and tumor vascularity compared to FNC-PBB-CS-NPs and free PBB. Additionally, in vivo optical imaging showed that the FNC-PBB-CS-SS-NPs accumulated more specifically in tumors than the other formulations. © 2025 American Chemical Society.
Quantitative recognition of volatile organics by fuzzy inference system based on discrete wavelet transform of SAW sensor transients
(IEEE Computer Society, 2014) Prashant Singh; Vivek Kumar Verma; Prabha Verma; R.D.S. Yadava
This paper explores nonlinearity in polymer coated surface acoustic wave (SAW) sensor responses for achieving enhanced quantitative vapor recognition capability. The analyses are based on the SAW sensor transients under step concentration exposure of volatile organic compounds. The sensor nonlinearity results from viscoelastic nature of films, and it depends on the film thickness and viscoelastic parameters of the film coating. The method of analysis involves representation of transient data in terms of discrete wavelet approximation coefficients and then application of Sugeno type fuzzy inference system based on fuzzy c-means clustering in wavelet space for simultaneous classification and concentration estimation. The simulation experiments are based on polyisobutylene (PIB) coating and exposure to 7 target vapors (chloroform, chlorobenzene, o-dichlorobenzene, n-Heptane, toluene, n-hexane and n-octane). By analyzing data as a function of film thickness for lossless and lossy conditions of film viscoelasticity it is found that there exists an optimum region of film thickness over which both the vapor classification rates and the concentration estimates suffer minimum error. © 2014 IEEE.
Room-Temperature-Stabilized Alpha Tin Nanocrystals for In Vivo Toxicology Evaluation and Photothermal Therapy Corroborated by FFT Modeling
(American Chemical Society, 2025) Shivesh Sabbarwal; Shreyasi Majumdar; Vivek Kumar Verma; Prachi Srivastava; Ahmad Nawaz; Virendra Pratap Singh; Biplob Koch; Sairam Krishnamurthy; Manoj Kumar
Herein, we unveil a remarkable finding for synthesizing room-temperature-stable, nontoxic, ultrasmall free-standing diamond cubic tin nanocrystals (α-Sn) with beta forms in the aqueous phase, avoiding conventional approaches that typically use toxic elements or large reactive substrates (Si/ InSb) to stabilize α-Sn above 13 °C. Herein, for the first time, we demonstrate the successful synthesis of free-standing alpha tin with extraordinary stability up to 80 °C and in the aqueous phase at room temperature, which was supported by powder X-ray diffraction and X-ray photoelectron spectroscopy characterization methods. This synthetic approach eliminates the need to use hazardous materials, bulky substrates, and elevated temperatures, offering a safer, low-cost, and more sustainable alternative. Prepared α-Sn is characterized by extraordinary NIR absorption and a photothermal efficiency of 42.4%, making it a promising photothermal agent for cancer treatment upon shining low-power (0.5 W) 980 nm NIR light using a CW laser. Using fast Fourier transform weighted bright-field imaging, a mathematical model that foretells the behavior of live malignant cells before and after photothermal treatment has been constructed. Additionally, in vivo studies in rats backed by biochemical and histopathological analyses demonstrated no adverse effects on the vital organs of Wister rats. The unusual biocompatibility of the prepared α-Sn nanocrystals is demonstrated by a low hemolysis index (3.28 ± 0.53%) of the blood, which is far below the permissible limits of 5%. Current research unveils the strong potential of free-standing alpha-tin not only in the area of nanomedicine but also in other domains. © 2024 American Chemical Society.
White Light Emitting Gadolinium Oxide Nanoclusters for In-vitro Bio-imaging
(John Wiley and Sons Inc, 2022) Vivek Kumar Verma; Prachi Srivastava; Shivesh Sabbarwal; Mamata Singh; Biplob Koch; Manoj Kumar
Fluorescent probes are highly desirable for accurate diagnosis and play a crucial role in the optical imaging modality. Here, ultrafine (1.2 nm) nanoclusters of undoped gadolinium oxide were synthesized via a simple, one-pot technique using water as the reaction medium. Prepared nanoclusters exhibit strong tuneable emission spanning from 400-620 nm (extended visible region) with broad full width at half maximum of (FWHM) ∼140 nm, resulting in white light emission (WLE). Cytotoxicity studies revealed nearly 100 % cell viability encouraging its application in cell imaging. These nanoclusters possessed distinctive properties such as wide-range pH stability, ionic tolerability, durable photostability, and anomalous colloidal stability (more than 24 months). This brief report uses white light-emitting gadolinium oxide (Gd2O3) nanoclusters as an optical probe for in-vitro fluorescence imaging. © 2022 Wiley-VCH GmbH.
White light-emitting, biocompatible, water-soluble metallic magnesium nanoclusters for bioimaging applications
(Institute of Physics, 2023) Prachi Srivastava; Vivek Kumar Verma; Shivesh Sabbarwal; Mamata Singh; Kedar Sahoo; Biplob Koch; Manoj Kumar
Ultra-small (1.6 nm), water-soluble, white light-emitting (WLE), highly stable (∼8 months) BSA templated metallic (Mg0) nanoclusters (fluorescent magnesium nanoclusters = FMNCs) is developed using the green and facile route. Synthesis was facilitated by the reduction of magnesium salt, where template bovine serum albumin is utilized as a reducing agent and ascorbic acid act as a capping agent to impart stability in water, thereby obtaining stabilized Mg0 nanoclusters In solution, stabilized Mg0 nanoclusters produce white light (450-620 nm with FWHM ∼120 nm) upon 366 nm light excitation. This white light emission was found to have a CIE coordinate of 0.30, 0.33 [pure white light CIE (0.33, 0.33)]. Taking advantage of WLE and ultrasmall size, FMNCs were used for in vitro fluorescence imaging of HaCaT cell lines, yielding blue (τ = 2.94 ns, with a relative of QY = 1.2 % w.r.t QS), green (τ = 3.07 ns; relative quantum yield of 4.6% w.r.t R6G) and red (τ = 0.3 ns) images. Further, incubation of FMNCs with HEK293 (Human embryonic kidney cell) and cancerous MDA-MB-231 (Breast cancer cell line) human cell lines yielded 100 % cell viability. Current work is envisioned to contribute significantly in the area of science, engineering, and nanomedicine. © 2022 IOP Publishing Ltd.