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A facile synthesis of glutathione-stabilized copper nanoclusters (CuNCs) is carried out in H 2 O/ tetrahydrofuran medium. The photophysical and morphological studies performed with as-synthesized CuNCs revealed the formation of green-emissive, stable, and smaller nanoclusters. The precise composition of these as-synthesized CuNCs was predicted with the aid of electrospray ionization mass spectrometry analysis as Cu 12 (SG) 9 . Furthermore, the systematic studies of the interaction of synthesized CuNCs with three plasmatic proteins, namely, bovine serum albumin (BSA), lysozyme (Lys), and hemoglobin (Hb) have been performed by using a series of spectroscopic studies. The conformational changes in these proteins upon interacting with CuNCs and their binding stoichiometries have been investigated from the combination of UV−visible and steady-state fluorescence measurements. The changes in the microenvironment of proteins caused by CuNCs were investigated by circular dichroism spectroscopy. Among these three proteins, BSA and Lys had a minor effect on the luminescence of CuNCs, which makes them suitable candidates for biological applications. There are no drastic changes in the microenvironment of NCs as well as proteins because of the possibilities of weak electrostatic and H-bonding interactions of CuNCs with BSA and Lys. The feasibility of strong metallophic interaction between the Fe 2+ present in the heme group of Hb and Cu(I) or -S atoms present in the CuNCs brings considerable changes in the photophysical activity of CuNCs and their interactions with Hb. The functional groups on NCs as well as active amino acid residues present in proteins play a crucial role in determining their interactions. This work shed a piece of knowledge on designing NCs for specific biological applications.

Atomically precise nanoclusters comprising 1–100 atoms have emerged as a new class of nanomaterials with intriguing size-dependent physicochemical properties. The significant changes in the properties of nanoclusters were observed in tailoring the number of metal atoms and ligands that determines their functions and applicability. Since 1990, thiolated gold nanoclusters have been studied. The separation of monodispersed clusters was crucial and time-consuming. To address these shortcomings, several separation techniques have made it possible to separate the series of metal nanoclusters with a precise composition of metals and ligands. Among these techniques, polyacrylamide gel electrophoresis was utilized for hydrophilic cluster separation. This review shall focus on the principle, operation and application of the polyacrylamide gel electrophoresis technique to encourage a greater understanding of the characteristics and usefulness of this method.

The luminescence property of highly oxidative transition metal nanostructures using Co, Ni and Cu are being challenging. Due to their high susceptibility for oxidation and non‐existence of appropriate synthesis methodologies and lack of efficient mechanism to confirm their luminescence properties. To overcome these shortcomings, herein we report a new synthesis strategy to develop a novel tripeptide thiolate ligand i. e., glutathione (GS) protected ultrasmall water‐soluble cobalt nanoclusters, Con(GS)m. As achieved Con(GS)m clusters were isolated from the crude CoGS using polyacrylamide gel electrophoresis (PAGE) technique. The PAGE separation for the crude CoGS sample resulted in three bands of varying sizes i. e., 2–5 nm (band 1), 6–18 nm (band 2) and 13–28 nm (band 3), which exhibits size‐dependent luminescence with quantum yields of 10 %, 7.5 % and 5.8 % respectively. Among them, the maximum quantum yield for the ultrasmall Con(GS)m nanoclusters from the band 1 exhibits a blue emission which could be as result of synergetic behaviour from the aggregation induced emission (AIE) and ligand‐metal‐metal charge transfer (LMMCT) relaxations offered by the triplet state of Con(GS)m nanoclusters. This significant results for the water‐soluble, highly robust and luminescent Con(GS)m nanoclusters confirm their potential ability to act as an alternative to expensive metal nanoparticles and conventional fluorescent materials for the technological and bioimaging applications.