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.
Nucleation at different temperature levels can provide quantitative insights into the energy barrier associated with sub-molecular nuclei. The accurate calculation of nucleation rates, thermodynamics, and interfacial energy for extremely small nanoclusters (1−2 nm) remains a challenge at high temperatures. Here, E 𝜶 , 𝚫G, 𝚫H, 𝚫S and A 𝜶 are computed to estimate the nucleation rate of ultra-small CaCO 3 pre-nucleation clusters (0.85 nm) from thermogravimetric analysis (TGA) experimental values in the temperature range from 555 to 795 K, by adopting the most accurate iterative iso-conversional method and random nucleation dependent differential function f (𝜶), respectively. On the basis of these analyses, four mathematical models are presented for computing nucleation rates (nuclei 𝛍m −2 min −1 ) and interfacial energy (mJ m −2 variation with temperature and conversion for CaCO 3 prenucleation clusters. Furthermore, experimental validation is also carried out in order to assess the existence of nucleation in CaCO 3 pre-nucleation clusters at high temperatures (500 °C) using X-ray diffraction and experimental z(𝜶) master plots. The TGA can be used to predict and understand nucleation rates for various nano systems.
Determination of temperature-dependent nucleation rate is a crucial parameter to accessing the kinetic and thermodynamic barrier linked with developing subatomic-sized nuclei, which tend to restrain the nucleation process. In this study, we exclusively compute the nucleation rate, thermodynamic parameters, and interfacial energy of ultra-small gadolinium oxide nanoclusters at high temperatures. Here, the apparent value of activation energy (Ea.) and pre-exponential kinetic factor (Aa) was precisely computed by utilizing the most accurate Vyazovkin advanced and KAS iso-conversional method, which was further exploited to estimate the thermodynamic parameters, nucleation rate, and interfacial energy of ~1 nm-sized gadolinium nanoclusters, in the temperature ranging from 555 to 780 K by appraising thermogravimetric data. The obtained Z (α) master plot suggested the existence of random nucleation within the BSA matrix of Gd2O3 nanoclusters at high temperature over a specified conversion value. Additionally, four mathematical models were proposed using the above finding to interpret the nucleation rate and interfacial energy concerning high temperature and specified conversion points for the first time.
Ultra-small (1.6 nm), water-soluble, white light-emitting (WLE), highly stable (~1 year)BSA templated metallic Mg nanoclusters (fluorescent magnesium nanoclusters=FMNCs) are 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 nanocluster. 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-vivo fluorescence imaging of HaCaT cell lines, yielding blue (τ = 2.94 ns, with 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.
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