Green synthesis of anticancerous honeycomb PtNPs clusters: Their alteration effect on BSA and HsDNA using fluorescence probe

Ultrasmall Au/Pt-loaded biocompatible albumin nanospheres to enhance photodynamic/catalytic therapy via triple amplification of glucose-oxidase/catalase/peroxidase

The weak catalytic activity of nanocatalysts and the insufficient endogenous hydrogen peroxide (H2O2) in tumor microenvironment (TME) seriously restricted the efficacy of catalytic therapy, and the non-degradability of inorganic nanocarriers was also unfavorable for their clinical applications. Herein, by depositing gold nanoparticles (AuNPs) and platinum nanoparticles (PtNPs) with ultrasmall size and modifying photosensitizer (IR808), a biocompatible bovine serum albumin (BSA) nanoplatform (BSA@Au/Pt-IR808) with triple-amplification of enzyme activity was constructed to enhance photodynamic therapy (PDT) and catalytic therapy. Ultrasmall AuNPs possessed glucose oxidase (GOx)-like activity, by which the self-supplying H2O2 accelerated the dual-enzyme activity of peroxidase (POD) and catalase (CAT) of ultrasmall PtNPs, promoting the generation of hydroxyl radical (·OH) and singlet oxygen (1O2). Compared with BSA-IR808 and BSA@Pt, the yields of 1O2 and ·OH of BSA@Au/Pt-IR808 increased by 38.2% and 18.6%. Under the combination action of photothermal therapy (PTT)/PDT/catalytic therapy of BSA@Au/Pt-IR808, the cell viability significantly reduced to 12.8%, and the tumors were completely eliminated, demonstrating the enhanced PDT and catalytic therapy against breast cancer.

Narciclasine, a novel topoisomerase I inhibitor, exhibited potent anti-cancer activity against cancer cells

DNA topoisomerases are essential nuclear enzymes in correcting topological DNA errors and maintaining DNA integrity. Topoisomerase inhibitors are a significant class of cancer chemotherapeutics with a definite curative effect. Natural products are a rich source of lead compounds for drug discovery, including anti-tumor drugs. In this study, we found that narciclasine (NCS), an amaryllidaceae alkaloid, is a novel inhibitor of topoisomerase I (topo I). Our data demonstrated that NCS inhibited topo I activity and reversed its unwinding effect on p-HOT DNA substrate. However, it had no obvious effect on topo II activity. The molecular mechanism of NCS inhibited topo I showed that NCS did not stabilize topo-DNA covalent complexes in cells, indicating that NCS is not a topo I poison. A blind docking result showed that NCS could bind to topo I, suggesting that NCS might be a topo I suppressor. Additionally, NCS exhibited a potent anti-proliferation effect in various cancer cells. NCS arrested the cell cycle at G2/M phase and induced cell apoptosis. Our study reveals the antitumor mechanisms of NCS and provides a good foundation for the development of anti-cancer drugs based on topo I inhibition.

Blue light-emitting fluorene–dendron hybridized polymers: optophysical features

In this manuscript, we have demonstrated an efficient and rapid synthetic strategy for preparation of new fluorene–dendron-hybridized blue light-emitting polymers P1–P7 by the reaction of 9,9 long-chain dialkylated fluorenes M2–M8 with dendronized monomer (M1) under microwave-assisted reaction condition. These fluorene–dendron-hybridized polymers P1–P7 were characterized using different spectroscopic techniques. Furthermore, the optophysical properties of these polymers P1–P7 were studied which revealed that these synthesized polymers P1–P7 have potential to emerge as capable materials in the development of diodes, particularly for blue light emission. In the future, similar approaches would be utilized for preparation of light-emitting polymer composite.

Economical gold recovery cycle from bio-sensing AuNPs: an application for nanowaste and COVID-19 testing kits

We report the controlled growth of biologically active compounds: gold nanoparticles (AuNPs) in various shapes, including their green synthesis, characterization, and studies of their applications towards biological, degradation and recycling. Using spectroscopic methods, studies on responsive binding mechanisms of AuNPs with biopolymers herring sperm deoxyribonucleic acid (hsDNA), bovine serum albumin (BSA), dyes degradation study, and exquisitely gold separation studies/recovery from nanowaste, COVID-19 testing kits, and pregnancy testing kits are discussed. The sensing ability of the AuNPs with biopolymers was investigated via various analytical techniques. The rate of degradation of various dyes in the presence and absence of AuNPs was studied by deploying stirring, IR, solar, and UV-Vis methods. AuNPs were found to be the most active cytotoxic agent against human breast cancer cell lines such as MCF-7 and MDAMB-468. Furthermore, an economical process for the recovery of gold traces from nanowaste, COVID-19 detection kits, and pregnancy testing kits was developed using inexpensive and eco-friendly α-cyclodextrin sugar. This method was found to be easy and safest in comparison with the universally accepted cyanidation process. In the future, small gold jewelry makers and related industries would benefit from the proposed gold-recycling process and it might contribute to their socio-economic growth. The methodologies proposed are also beneficial for trace-level forensic investigation.

Click gold quantum dots biosynthesis with conjugation of quercetin for adenocarcinoma exertion

We developed a cost-effective and eco-friendly click biosynthesis of small molecule quercetin-gold quantum dots (QRT-AuQDs) involving quick conjugation using an ultrasonication method at ambient temperature by utilizing QRT and gold ions in the proportion of 0.1 : 1 (molar ratio). A comparatively very short amount of time (60 seconds) was required as compared to conventional procedures. The present biomimetics research relates to the isolation of bioactive QRT by the circularly spread silica gel layer technique (CSSGLT) and characterization (UV-Vis, FTIR, NMR and DSC analysis). Characterization of the synthesized QRT-AuQDs conjugated complex was carried out by UV-Vis, HR-TEM, DLS, zeta potential and X-ray diffraction. The main objective of the present work was to study the comparative anticancer activity of QRT and QRT-AuQDs on human lung cancer HOP-62 and leukemia K-562 cell lines. The results suggested that QRT-AuQDs showed potential for applications in anticancer treatment and were found to be a more cytotoxic agent in comparison to QRT, causing > 50% inhibition of cancer cells at the concentration < 10-7 M. Hence, small molecule conjugated QRT-AuQDs can be used as a promising material for biomedical, bioengineering and anti-infectives applications.

Deciphering the sensing of α-amyrin acetate with hs-DNA: a multipronged biological probe

In this study, we focus on the biomimetic development of small molecules and their biological sensing with DNA. The binding of herring sperm deoxyribonucleic acid (hs-DNA) with naturally occurring bioactive small molecule α-amyrin acetate (α-AA), a biomimetic - isolated from the leaves of Ficus (F.) arnottiana is investigated. Collective information from various imaging, spectroscopic and biophysical experiments provides evidence that α-AA is a minor groove sensor of hs-DNA and preferentially binds to the A-T-rich regions. Interactions of different concentrations of small molecule α-AA with hsDNA were evaluated via various analytical techniques such as UV-Vis, circular dichroism (CD) and fluorescence emission spectroscopy. Fluorescence emission spectroscopy results suggest that α-AA decreases the emission level of hsDNA. DNA minor groove sensor Hoechst 33258 and intercalative sensor EB, melting transition analysis (T M) and viscosity analysis clarified that α-AA binds to hs-DNA via a groove site. Biophysical chemistry and molecular docking studies show that hydrophobic interactions play a major role in this binding. The present research deals with a natural product biosynthesis-linked chemical-biology interface sensor as a biological probe for α-AA: hs-DNA.

Biological macromolecule chitosan grafted co-polymeric composite: bio-adsorption probe on cationic dyes

Chitosan biological macromolecule is a versatile polymer; chemical modification has been carried out that lead to the formation of chitosan grafted polymers composites (Chito-g-PC). We proposed synthesis of six various Chito-g-PC as sorbents for toxic dyes. A novel graft copolymerization method based on radical polymerization with vinyl monomer like acrylic acid, acrylamide, N-isopropylacrylamide, methacrylic acid and polyacrylonitrile were utilized in order to address the large amount of swelling at four different pH buffers solution. The effect of initiator and monomer concentration, time and temperature on % grafting and % grafting efficiency were performed. Comparative characterization of Chito and Chito-g-PC were evaluated by SEM, XRD and FTIR, as well as solubility characteristics of the composites were determined by various pH buffer solution. Cationic toxic dyes Malachite green (MG) and Methylene blue (MB) were selected as the sorbet, and Chito-g-PC were used as biosorbents. Thermodynamic analysis showed that the sorption process was spontaneous and endothermic with an increased randomness. The sorption experiments were realized with six different Chito-g-PC for MG and MB at various pH.

A simple reagent-less approach using electrical discharge as a substitution for chelating agent in addressing genomic assay inhibition by divalent cations

Electrical discharge treatment was shown to be a viable substitution for chelating agent in genomic assays. Divalent cation Mg2+ inhibits the performance of DNA hybridization based genomic assays by binding to the DNA and disrupting DNA hybridization. Until now, chelating agents such as ethylenediaminetetraacetic acid (EDTA) was the only option to address the presence of Mg2+ in samples. However, EDTA is a well-known environmental contaminant. In this work, we successfully employed electrical discharge instead of EDTA to render Mg2+ insipid. Its preliminary efficacy was first observed via circular dichroism (CD) and zeta potential analyses. After electrical discharge treatment, the reduction in CD shift at 280 nm was significant for samples with 10-3 and 10-8 M Mg2+. The zeta potential of Mg2+ laden samples were also restored from -4.71 ± 1.38 to -20.59 ± 6.37 mV after electrical discharge treatment. Both CD shift and change in zeta potential suggested that 2 min of electrical discharge treatment could prevent Mg2+ from binding to DNA. The complete efficacy of electrical discharge treatment was demonstrated with the performance recovery (within ∼15% of the control) of a genomic assay variant (NanoGene assay) while analyzing Mg2+ laden samples (10-5-10-3 M). Assuming 10 million samples are analyzed annually, the proposed electrical discharge treatment (∼50 mW per sample) would allow us to trade environmental contamination by ∼50 kg of hazardous EDTA with a single 250 W STC (standard test conditions) solar panel.

Nanocomposite of functional silver metal containing curcumin biomolecule model systems: Protein BSA bioavailability

Curcumin, a constituent of Curcuma longa L-Zingiberaceae is used in traditional Indian and worldwide medicine and shows anticancer and antioxidant properties. Curcumin has numerous biological and pharmacological activities but due to its hydrophobic nature, the major drawback is poor absorption and rapid elimination, rendering curcumin with the tag of a poor biomaterial. Hence, there is a need to develop functional metal containing curcumin model systems (FMCCMS) as a metallo-biomolecule to enhance the bioavailability of curcumin. We designed the interaction of silver metal ion with curcumin to form curcumin-silver nanocomposite (CURC-AgNCP) via ultrasonic synthetic route. Formations of FMCCMS were characterized by spectroscopic techniques. The crystalline face-centered cubic pattern and particle size of the nanocomposite was evaluated using X-ray diffraction and high-resolution transmission electron microscopy. The bonding of silver metal to curcumin was confirmed by X-ray photon spectroscopy. Interaction of the nanocomposite with bovine serum albumin (BSA) protein was performed using excitation, emission, and circular dichroism spectroscopy. In binding interaction of BSA, the negative value of ∆S° (-358.04 J mol^-1 K^-1) and ∆H° (-129.42 KJ mol^-1) demonstrates the hydrophilic nature of the nanocomposite. The binding distance r evaluated according to the Forster resonance energy transfer theory and was 4.69 nm for CURC-AgNCP, which suggested non-radiative transfer of energy between CURC-AgNCP and BSA. The role of FMCCMS metallo-biomolecule CURC-AgNCP in medicine for cancer activity can have immense importance and hence we performed Sulphorhodamine B based in-vitro cytotoxicity assay on human breast cancer Michigan Cancer Foundation-7 cell line.

Ultrasonic-promoted rapid preparation of PVC/TiO2-BSA nanocomposites: Characterization and photocatalytic degradation of methylene blue

In the present project in order to prevent agglomeration and better dispersion of TiO₂ nanoparticles (NPs) in the poly(vinyl chloride) (PVC) matrix, initially, the surface of TiO₂ NPs was covered by bovine serum albumin protein (BSA) via sonication method. Then, the TiO₂-BSA powders were embedded into the PVC matrix using ultrasonic irradiations. With mechanical and magnetic stirring homogenous mixture was not obtained. So sonication process was very essential and vital. Physical, chemical and structural properties of the samples were investigated with various tools. Morphology studies showed the well distribution of spherical TiO₂ NPs in the PVC matrix. TGA analysis showed that nanocomposites (NCs) have higher thermal stability than the pristine polymer. The photocatalytic activity tests by destroying the methylene blue dye on the pristine TiO₂ NPs, TiO₂-BSA NPs and PVC/TiO₂-BSA NC 6 wt% were examined. The results showed that the photocatalytic activity of TiO₂ NPs was reduced in the presence of BSA and PVC. It can be concluded that the TiO₂-BSA NPs and PVC/TiO₂-BSA NC 6 wt% have UV shielding properties and can protect film from degradation by UV.

Discrete SeNPs-Macromolecule Binding Manipulated by Hydrophilic Interaction

Nanoparticle-protein conjugates are promising probes for biological diagnostics and versatile building blocks for nanotechnology. Here we demonstrate the interaction of SeNPs with BSA macromolecule simply by physical adsorption method. The interaction between SeNPs and BSA has been investigated by UV-Vis, fluorescence, circular dichroism (CD) spectroscopic and thermal methods. The esterase-like activity of BSA towards PNPA was investigated in the presence of SeNPs. The effects of SeNPs on the stability and conformational changes of BSA were studied, which indicated that the binding of SeNPs with BSA induced relative changes in secondary structure of protein. SeNPs acted as a structure stabilizer for BSA which was further confirmed by thermal denaturation study. The hydrophilic bonding forces played important roles in the BSA-SeNPs complex formation. The putative binding site of SeNPs on BSA was near to Sudlow's site II. The hydrophilic interaction of SeNPs on the stability and structure of BSA would find promising application in drug delivery system.

Recent advances in green nanoparticulate systems for drug delivery: efficient delivery and safety concern

Nanotechnology manipulates therapeutic agents at the nanoscale for the development of nanomedicines. However, there are current concerns over nanomedicines, mainly related to the possible toxicity of nanomaterials used for health medications. Due to their small size, they can enter the human body more readily than larger sized particles. Green chemistry encompasses the green synthesis of drug-loaded nanoparticles by reducing the use of hazardous materials in the synthesis process, thus reducing the adverse health impacts of pharmaceutics. This would greatly expand their potential in biomedical treatments. This review highlights the potential risks of nanomedicine formulations to health, delivery routes of green nanomedicines, recent advances in the development of green nanoscale systems for biomedical applications and future perspectives for the green development of nanomedicines.