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Zinc oxide nanoparticle with negative surface potential (ZnONP) enhances bovine insulin fibrillation. Here, we are exploring ZnONP with positive surface potential (ZnONPUnc) and surface functionalized with tyrosine and tryptophan amino acids to observe the effects of surface potential and surface functional groups on the fibrillation. ZnONPUnc, despite of inversed surface potential, enhances the insulin fibrillation with increase in the interface concentration at physiological pH. Whereas, the interface moderation with the amino acids mitigates the surface-mediated insulin fibrillation propensity. Additionally, the study indicates that the change in interfacial functional groups at ZnONPUnc significantly reverses the interface-mediated destabilization of insulin conformation. The functional groups from the amino acids, like C O, N–H and aromatic functional groups, are anticipated to further stabilize the insulin conformation by forming hydrogen bond and van der Waals interactions with the key amyloidogenic sequences of insulin, A13-A20 from A-chain and B9–B20 from B-chain. Hence, the altered interaction profile, with change in interfacial functional groups, mitigates the interface-mediated insulin fibrillation and the ZnONPUnc-/fibril-mediated cytotoxicity.

In the current study, biogenic silver nanoparticles (U-AgNPs) were synthesized using marine green macro-algal Ulva lactuca extract, and evaluated mechanism behind its anticancer activity against the Human colon cancer (HCT-116). The biogenic U-AgNPs were characterized using various physiochemical techniques. The TEM micrographs confirmed the spherical morphology of synthesized U-AgNPs, with a mean size of 8–14 nm. EDX spectrum as well as ICP-OES confirmed that AgNPs was nearly 90% purity for silver. FTIR Spectra analysis of U-AgNPs confirmed U. lactuca extract bioactive molecules presence over U-AgNPs surface as a stabilizing agent, thereby improving biocompatibility. The cytotoxicity study revealed the dose dependent cell death in colon cancer cells with no loss of viability in normal human colon epithelial cells. Furthermore, the fluorescence micrographs of nucleus staining assay revealed the DNA fragmentation and nucleus condensation of cancer cells treated with U-AgNPs, indicating an apoptosis-mediated cell death. The western bolt and RT-PCR analysis of U-AgNPs treated cancer cells showed the rise in proapoptotic markers (P53, Bax, and P21) and decline in anti-apoptotic markers (Bcl-2), thus confirming the p53-dependent apoptosis mediated cell death in HCT-116. Overall, our study concluded that novel biogenic U-AgNPs nanoparticles, synthesized using marine green macro-algal U. lactuca extract showed efficient anticancer activity against HCT-116 cell line and hence could work as potential therapeutic agent for targeted anti-cancer therapy.

Green synthesis approaches for nanoparticle synthesis are considered as nontoxic, eco-friendly and cost-effective approaches than other physical and chemical approaches. Here, we report green synthesis of silver nanoparticle using the bacteria from the habitat of relatively metal-rich coal mine dust. The bacteria showed resistance to significant concentration of anti-microbial Ag(I) ion. The nanoparticle was synthesized at minimum inhibitory concentration (MIC) of Ag(I) using only two isolates. The synthesis of silver nanoparticle was confirmed from the surface plasmon resonance property of the nanoparticle, whereas morphological features were studied using field emission scanning electron microscope. The hydrodynamic size analysis showed the presence of microparticles along with the nanoparticles. Additionally, IR study provided information about the bacterial proteins involved in either reduction of Ag(I) into silver nanoparticle or capping of reduced silver nanocrystal or both. Thus, majority of the bacteria found in the coal mines have the resistance against the antimicrobial metal ion, and the potential to reduce the ion into nano- or micro-particles. Hence, the bacteria can be used as a single cell factory for production of silver nanomaterial.

The aim of present investigation is to explore the effect of zinc oxide nanoparticles (ZnONP, 30 nm) interface on conformational dynamics and stability of lysozyme, at pH 7.4 and pH 9.0. Lysozyme adopts partially disordered conformation at pH 9.0, which adopts fibril morphology in presence of sodium dodecyl sulfate (SDS), compared to the conformation adopted at pH 7.4. However, the presence of ZnONP interface renders partially disordered lysozyme relatively regular and non-amyloidogenic conformation, and enhances the functional efficacy of lysozyme at pH 9.0. Additionally, the thermograms reveal a non-cooperative unfolding of the pH 9.0 lysozyme conformation, which accompanied with intermediate conformations that increased with increase in the interface concentration. The binding thermodynamics indicate that at pH 9.0, lysozyme conformation preferentially binds to ZnONP interface than SDS interface. The preferential binding is attributed for the resulting anti-fibrillation propensity of ZnONP interface. The data, altogether, suggest that the presence of ZnONP interface resulted in conformational rearrangements in the partially disordered lysozyme at pH 9.0 causing accumulation of non-amyloidogenic and functionally active intermediates, thus shielding the lysozyme from SDS induced fibrillation and cytotoxicity.