Selenium-Containing Amphiphiles Reduced and Stabilized Gold Nanoparticles: Kill Cancer Cells via Reactive Oxygen Species

Design and development of locust bean gum-endowed/Phyllanthus reticulatus anthocyanin- functionalized biogenic gold nanosystem for enhanced antioxidative and anticancer chemotherapy

Herein, the design and fabrication of an anticancer nanoplatform (LBG/PRA-NG) based on locust bean gum-stabilized nanogold and functionalized with Phyllanthus reticulatus anthocyanins was described. LBG/PRA-NG was prepared in an eco-friendly, one-pot approach at room temperature, mediated by the anthocyanins and gum as bio-reductant and stabilizer, respectively. The nanostructure was elaborately characterized by FESEM, TEM, UV-visible, DLS, Zeta potential, FTIR, XRD, TGA/DTG, and XPS analysis. Its anticancer attributes were examined based on cytotoxicity on MCF-7 and MDA-MB-231 breast cancer cell lines, as well as the generation of intracellular reactive oxygen species. The results revealed the successful formation of a homogenous and highly stable nanocomposite (LBG/PRA-NG), with quasi-spherical shape, small size (14.73 nm), Zeta potential and PDI values of -58.30 mV and 0.237, respectively. The presence of a plasmonic peak at 525 nm was indicative of AuNPs. Compared to the galactomannan and anthocyanin, LBG/PRA-NG exhibited superior antioxidative properties with IC50 values of 35.44 μg/mL against DPPH and 24.55 μg/mL against ABTS+. Notably, LBG/PRA-NG also demonstrated enhanced anticancer properties relative to LBG and anthocyanins, with IC50 values of 16.17 μg/mL and 25.06 μg/mL against MCF-7 and MDA-MB-231 cells. Meanwhile, the normal cells (HEK-293 and L929) resisted the innocuous effects of LBG/PRA-NG. Furthermore, treatment of breast cancer cells with LBG/PRA-NG drastically elevated the intracellular ROS levels. This suggested that the anticancer activity of LBG/PRA-NG may be mediated via amplification of ROS/oxidative stress-induced apoptosis. Altogether, these findings indicate the remarkable potential of LBG/PRA-NC in the development of anticancer therapy.

Comparative Study of ZnO-and-TiO2-Nanoparticles-Functionalized Polyvinyl Alcohol/Chitosan Bionanocomposites for Multifunctional Biomedical Applications

This study aimed to synthesize chitosan/polyvinyl alcohol (CS/PVA)-based zinc oxide (ZnO) and titanium dioxide (TiO2) hybrid bionanocomposites (BNCs) and observe their comparative accomplishment against the skin cancer cell line, A431, and antioxidant potential. CS was blended with PVA to form polymeric films reinforced with the immobilization of ZnO and TiO2 nanoparticles (NPs), separately. The optimization of the BNCs was done via physicochemical studies, viz. moisture content, swelling ratio, and contact angle measurements. The free radical scavenging activity was observed for 1,1-diphenyl-2-picryl-hydrazyl, and the antibacterial assay against the Escherichia coli strain showed a higher zone of inhibition. Furthermore, the anticancer activity of the synthesized BNCs was revealed against the skin cancer cell line A431 under varying concentrations of 50, 100, 150, 200, and 300 μg/mL. The anticancer study revealed a high percent of cancerous cell inhibition (70%) in ZnO BNCs as compared to (61%) TiO2 BNCs in a dose-dependent manner.

Organoselenium compounds as functionalizing agents for gold nanoparticles in cancer therapy

Gold nanoparticles (AuNPs) modified with four organoselenium compounds, i.e., 4-selenocyanatoaniline (compound 1), 4,4'-diselanediyldianiline (compound 2), N-(4-selenocyanatophenyl)cinnamamide (compound 3), and N-(3-selenocyanatopropyl)cinnamamide (compound 4), were synthesized following two different approaches: direct conjugation and non-covalent immobilization onto hydrophilic and non-cytotoxic AuNPs functionalized with 3-mercapto-1-propanesulfonate (3MPS). Both free compounds and AuNPs-based systems were characterized via UV-Vis, FTIR NMR, mass spectrometry, and SR-XPS to assess their optical and structural properties. Size and colloidal stability were evaluated by DLS and ζ-potential measurements, whereas morphology at solid-state was evaluated by atomic force (AFM) and scanning electron (FESEM) microscopies. AuNPs synthesized through chemical reduction method in presence of Se-based compounds as functionalizing agents allowed the formation of aggregated NPs with little to no solubility in aqueous media. To improve their hydrophilicity and stability mixed AuNPs-3MPS-1 were synthesized. Besides, Se-loaded AuNPs-3MPS revealed to be the most suitable systems for biological studies in terms of size and colloidal stability. Selenium derivatives and AuNPs were tested in vitro via MTT assay against PC-3 (prostatic adenocarcinoma) and HCT-116 (colorectal carcinoma) cell lines. Compared to free compounds, direct functionalization onto AuNPs with formation of Au-Se covalent bond led to non-cytotoxic systems in the concentration range explored (0-100 μg/mL), whereas immobilization on AuNPs-3MPS improved the cytotoxicity of compounds 1, 3, and 4. Selective anticancer response against HCT-116 cells was obtained by AuNPs-3MPS-1. These results demonstrated that AuNPs can be used as a platform to tune the in vitro biological activity of organoselenium compounds.

Prospecting Cellular Gold Nanoparticle Biomineralization as a Viable Alternative to Prefabricated Gold Nanoparticles

Gold nanoparticles (GNPs) have shown considerable potential in a vast number of biomedical applications. However, currently there are no clinically approved injectable GNP formulations. Conversely, gold salts have been used in the clinic for nearly a century. Further, there is evidence of GNP formation in patients treated with gold salts (i.e., chrysiasis). Recent reports evaluating this phenomenon in human cells and in murine models indicate that the use of gold ions for in situ formation of theranostic GNPs could greatly improve the delivery within dense biological tissues, increase efficiency of intracellular gold uptake, and specificity of GNP formation within cancer cells. These attributes in combination with safe clinical application of gold salts make this process a viable strategy for clinical translation. Here, the first summary of the current knowledge related to GNP biomineralization in mammalian cells is provided along with critical assessment of potential biomedical applications of this newly emergent field.

Copper-Selenocysteine Quantum Dots for NIR-II Photothermally Enhanced Chemodynamic Therapy

Chemodynamic therapy has been appealing for effective cancer treatment. Particularly, Fenton-like reactions catalyzed by Cu²⁺-based nanoparticles showed promising prospects. Herein, we fabricated copper-selenocysteine quantum dots (Cu-Sec QDs) with the majority of Cu⁺ by a facile and robust thermal titration process. No high temperature or pressure is needed for this synthetic route of QDs. The selenocysteine functioned as the reducing agent as well as the stabilizer, circumventing the poor water solubility and stability, leading to enhanced biocompatibility. The existence of Cu⁺ endowed the QDs the ability to catalyze the Fenton-like reaction without an extra reduction reaction of Cu²⁺ to Cu⁺. Moreover, the strong absorption in the near-infrared-II region (1000-1300 nm) of the final Cu-Sec QDs is in great favor of the chemodynamic therapy via the photothermally enhanced Fenton-like reaction. And the Cu-Sec QDs exhibited obvious cytotoxicity to various cancer cell lines. We believe that this facile and robust synthetic approach could open up another method for the fabrication of quantum dots toward the potential Fenton-like reaction-based applications in biological fields.

Fingerprinting Metabolic Activity and Tissue Integrity of 3D Lung Cancer Spheroids under Gold Nanowire Treatment

Inadequacy of most animal models for drug efficacy assessments has led to the development of improved in vitro models capable of mimicking in vivo exposure scenarios. Among others, 3D multicellular spheroid technology is considered to be one of the promising alternatives in the pharmaceutical drug discovery process. In addition to its physiological relevance, this method fulfills high-throughput and low-cost requirements for preclinical cell-based assays. Despite the increasing applications of spheroid technology in pharmaceutical screening, its application, in nanotoxicity testing is still in its infancy due to the limited penetration and uptake rates into 3D-cell assemblies. To gain a better understanding of gold nanowires (AuNWs) interactions with 3D spheroids, a comparative study of 2D monolayer cultures and 3D multicellular spheroids was conducted using two lung cancer cell lines (A549 and PC9). Cell apoptosis (live/dead assay), metabolic activity, and spheroid integrity were evaluated following exposure to AuNWs at different dose-time manners. Results revealed a distinct different cellular response between 2D and 3D cell cultures during AuNWs treatment including metabolic rates, cell viability, dose–response curves and, uptake rates. Our data also highlighted further need for more physiologically relevant tissue models to investigate in depth nanomaterial–biology interactions. It is important to note that higher concentrations of AuNWs with lower exposure times and lower concentrations of AuNWs with higher exposure times of 3 days resulted in the loss of spheroid integrity by disrupting cell–cell contacts. These findings could help to increase the understanding of AuNWs-induced toxicity on tissue levels and also contribute to the establishment of new analytical approaches for toxicological and drug screening studies.

Facile Synthesis of Gold Nanoparticles for Anticancer, Antioxidant Applications, and Photocatalytic Degradation of Toxic Organic Pollutants

In the current study, a facile, rapid, and ecologically safe photosynthesis of gold nanoparticles (AuNPs) that remained stable for 3 months is reported to advocate the main aspects of green chemistry, such as safer solvents and auxiliaries, and the use of renewable feedstock. Zi-AuNPs were phytosynthesized by the aqueous extract of Ziziphus spina-christi leaves, and numerous techniques were employed for their characterization. The results demonstrated the successful phytofabrication of crystalline AuNPs with brownish-black color, spherical nanoparticles with a size between 0 and 10 nm, a plasmon peak at 540 nm, and a surface charge of -25.7 mV. Zi-AuNPs showed an effective photodegradation efficiency (81.14%) against malachite green and a good recycling capacity of 69.2% after five cycles of regeneration. The cytotoxicity test by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay signified a high anticancer efficiency for both Zi-AuNPs and Z. spina-christi extract against human breast cancer cells (MCF7 cell line) with IC₅₀'s of 48 and 40.25 μg/mL, respectively. Highly efficient antioxidant capabilities were proven with 2,2-diphenyl-1-picrylhydrazyl (DPPH) removal percentages of 67.5% for Zi-AuNPs and 92.34% for Z. spina-christi extract.

Reactive Oxygen Species Responsive Polymers for Drug Delivery Systems

Reactive oxygen species (ROS) play an essential role in regulating various physiological functions of living organisms; however, as the concentration of ROS increases in the area of a lesion, this may undermine cellular homeostasis, leading to a series of diseases. Using cell-product species as triggers for targeted regulation of polymer structures and activity represents a promising approach for the treatment. ROS-responsive polymer carriers allow the targeted delivery of drugs, reduce toxicity and side effects on normal cells, and control the release of drugs, which are all advantages compared with traditional small-molecule chemotherapy agents. These formulations have attracted great interest due to their potential applications in biomedicine. In this review, recent progresses on ROS responsive polymer carriers are summarized, with a focus on the chemical mechanism of ROS-responsive polymers and the design of molecular structures for targeted drug delivery and controlled drug release. Meanwhile, we discuss the challenges and future prospects of its applications.

Blood circulation stable doxorubicin prodrug nanoparticles containing hydrazone and thioketal moieties for antitumor chemotherapy

Prodrug nanoparticles with cleavable moieties sensitive to intracellular stimuli have drawn great attention on cancer chemotherapy. Herein, a reactive oxygen species (ROS)-responsive doxorubicin prodrug mPEG-Phe-TK-Phe-hyd-DOX was synthesized, in which hydrophilic methoxy poly(ethylene glycol) (mPEG) and hydrophobic anticancer drug doxorubicin (DOX) were conjugated with hydrazone (hyd) and ROS-responsive thioketal (TK) moieties. The ROS-responsiveness of prodrug was confirmed by proton nuclear magnetic resonance (¹H NMR) and dynamic light scattering (DLS). Unexpectedly, the results of in vitro drug release indicated that the hydrazone bond of prodrug nanoparticles was insensitive to pH, which may be due to the strong hydrophobicity, π-π interactions and cation-π interactions jointly inhibited the hydrolysis of hydrazone bonds under acidic conditions. The cellular uptake and in vitro anticancer study showed that ROS-responsive prodrug nanoparticles exhibited faster cellular uptake and better anticancer efficacy. The in vivo experiments showed that the ROS-responsive prodrug nanoparticles had comparable antitumor efficacy with free anticancer drug DOX and reduced organ toxicity. Our results provide novel idea of successfully design multi-stimuli-responsive nano-drug carrier.

A Drug-Free Therapeutic System for Cancer Therapy by Diselenide-Based Polymers Themselves

The application of nanotechnology-based drug delivery systems has resulted in great progresses in cancer therapy. However, current systems ultimately depend on the action of the drug itself and almost all nanocarriers only serve as excipients without any therapeutic efficacy. Herein, a drug-free therapeutic system is put forward, in which synthetic polymers themselves naturally exhibit effective anticancer activity without the loading of additional chemotherapy drugs. Aiming at this goal, amphiphilic poly(diselenide-carbonate) copolymers (PSeSeTMC), consisting of monomethyl ether poly(ethylene glycol) and diselenide-based polycarbonates, are designed and synthesized to build spherical nanoparticles, which show effective and broad-spectrum anticancer activities against multiple cancer cell lines and high selectivity toward cancer cells. Moreover, the anticancer activities can be well controlled by tuning the selenium contents in polymers. Mechanistic investigations indicate that PSeSeTMC can selectively induce cancer cells to express excessive reactive oxygen species, thereby leading to significant cellular apoptosis. In vivo antitumor studies further demonstrate high therapeutic efficacy and low side effects on normal tissue. Overall, this work provides a novel approach for cancer therapy by utilizing carriers themselves. Considering the fabrication process is pretty simple, this diselenide-based polymeric system has great potential in clinical translation.

Diselenide–yne polymerization for multifunctional selenium-containing hyperbranched polymers

Diselenide–yne polymerization for multifunctional selenium-containing hyperbranched polymers.

Lewis acid-promoted formation of benzoselenazole derivatives using SeO2 as a selenium source

A new one-pot method of using both ortho-inactivated anilines and acetophenones (or methylquinolines) which possess an active H in the α-position of ketones (or benzyl positions) as starting materials to make benzoselenazole derivatives has been developed, which uses SeO2 as a selenium agent. This method first establishes SeO2 as a source of selenium to form benzoselenazole derivatives, which enriches the synthesis method of benzoselenazole. This method has several advantages, including good yields, simple operation, and availability of raw materials. Furthermore, the reaction could be easily scaled and its practical value in organic synthesis is displayed.

Gold Nanoparticle-Redox Ionic Liquid based Nanoconjugated Matrix as a Novel Multifunctional Biosensing Interface

Creation of interfaces with a prudent design for the immobilization of biomolecules is substantial in the construction of biosensors for real-time monitoring. Herein, an adept biosensing interface was developed using a nanoconjugated matrix and has been employed toward the electrochemical determination of hydrogen peroxide (H₂O₂). The anionic gold nanoparticle (AuNP) was electrostatically tethered to cationic redox ionic liquid (IL), to which the horseradish peroxidase (HRP) enzyme was covalently immobilized to form a nanobioconjugate. The anthracene-substituted, aldehyde-functionalized redox IL (CHO-AIL) was judiciously designed with the (i) imidazolium cation for electrostatic interaction with AuNPs, (ii) anthracene moiety to mediate the electron transfer, and (iii) free aldehydic group for covalent bonding with a free amine group of the enzyme. Thus, the water-soluble HRP is effectively bonded to the CHO-AIL on a glassy carbon electrode (GCE) via imine bond formation, which resulted in the formation of the HRP-CHO-AIL/GCE. Electrochemical investigations on the HRP-CHO-AIL/GCE reveal highly stable and distinct redox peaks for the anthracene/anthracenium couple at a formal potential (E°') of -0.47 V. Electrostatic tethering of anionic AuNPs to the HRP-CHO-AIL promotes the electron transfer process in the HRP-CHO-AIL/AuNPs/GCE, as observed by the reduction in the formal potential to -0.42 V along with the enhancement in peak currents. The HRP-CHO-AIL/AuNPs/GCE has been explored toward the electrocatalytic detection of H₂O₂, and the modified electrode demonstrated a linear response toward H₂O₂ in the concentration range of 0.02-2.77 mM with a detection limit of 3.7 μM. The developed biosensor ascertained predominant selectivity and sensitivity in addition to remarkable stability and reproducibility, corroborating the suitableness of the platform for the effectual biosensing of H₂O₂. The eminent performance realized with our biosensor setup is ascribed to the multifunctional efficacy of this newly designed nanobioconjugate.

Wireless Electrochemotherapy by Selenium-Doped Piezoelectric Biomaterials to Enhance Cancer Cell Apoptosis

Cancer residues around the surgical site remain a significant cause of treatment failure with cancer recurrence. To prevent cancer recurrence and simultaneously repair surgery-caused defects, it is urgent to develop implantable biomaterials with anticancer ability and good biological activity. In this work, a functionalized implant is successfully fabricated by doping the effective anticancer element selenium (Se) into the potassium-sodium niobate piezoceramic, which realizes the wireless combination of electrotherapy and chemotherapy. Herein, we demonstrate that the Se-doped piezoelectric implant can cause mitochondrial damage by increasing intracellular reactive oxygen species levels and then trigger the caspase-3 pathway to significantly promote apoptosis of osteosarcoma cells in vitro. Meanwhile, its good biocompatibility has been verified. These results are of great importance for future deployment of wireless electro- and chemostimulation to modulate biological process around the defective tissue.

In vitro evaluation of bone cements impregnated with selenium nanoparticles stabilized by phosphatidylcholine (PC) for application in bone

One of the most common prophylactic techniques to solve prosthetic joint infection (PJI) is incorporation of antibiotics into acrylic bone cement to prevent bacterial colonization and proliferation by providing local antibiotic delivery directly at the implant site. Further, there has been a significant concern over the efficacy of commonly used antibiotics within bone cement due to the rise in multi-drug resistant (MDR) microorganisms. Selenium is an essential trace element that has multiple beneficial effects for human health and its chemotherapeutic action is well known. It was reported that nanostructured selenium enhanced bone cell adhesion and has an increased osteoblast function. In this context, we used the selenium nanoparticles (SeNPs) to improve antibacterial and antioxidant properties of poly (methyl methacrylate) (PMMA) and tri calcium phosphate (TCP)-based bone cements, and to reduce of the infection risk caused by orthopedic implants. As another novelty of this study, we proposed phosphatidylcholine (PC) as a unique and natural stabilizer in the synthesis of selenium nanoparticles. After the structural analysis of the prepared bone cements was performed, in vitro osteointegration and antibacterial efficiency were tested using MC3T-E1 (mouse osteoblastic cell line) and SaOS-2 (human primary osteogenic sarcoma) cell lines, and S. aureus (Gram positive) and E.coli (Gram negative) strains, respectively. More importantly, PC-SeNPs-reinforced bone cements exhibited significant effect against E. coli, compared to S. aureus and a dose-dependent antibacterial activity against both bacterial strains tested. Meanwhile, these bone cements induced the apoptosis of SaOS-2 through increased reactive oxygen species without negatively influencing the viability of the healthy cell line. Furthermore, the obtained confocal images revealed that PC-SeNPs (103.7 ± 0.56 nm) altered the cytoskeletal structure of SaOS-2 owing to SeNPs-induced apoptosis, when MC3T3-E1 cells showed a typical spindle-shaped morphology. Taken together, these results highlighted the potential of PC-SeNPs-doped bone cements as an effective graft material in bone applications.

Reactive Oxygen Species-Related Nanoparticle Toxicity in the Biomedical Field

The unique physicochemical characteristics of nanoparticles have recently gained increasing attention in a diverse set of applications, particularly in the biomedical field. However, concerns about the potential toxicological effects of nanoparticles remain, as they have a higher tendency to generate excessive amounts of reactive oxygen species (ROS). Due to the strong oxidation potential, the excess ROS induced by nanoparticles can result in the damage of biomolecules and organelle structures and lead to protein oxidative carbonylation, lipid peroxidation, DNA/RNA breakage, and membrane structure destruction, which further cause necrosis, apoptosis, or even mutagenesis. This review aims to give a summary of the mechanisms and responsible for ROS generation by nanoparticles at the cellular level and provide insights into the mechanics of ROS-mediated biotoxicity. We summarize the literature on nanoparticle toxicity and suggest strategies to optimize nanoparticles for biomedical applications.

Enzyme-Like Properties of Gold Clusters for Biomedical Application

In recent years, the rapid development of nanoscience and technology has provided a new opportunity for the development and preparation of new inorganic enzymes. Nanozyme is a new generation of artificial mimetic enzyme, which like natural enzymes, can efficiently catalyze the substrate of enzyme under mild conditions, exhibiting catalytic efficiency, and enzymatic reaction kinetics similar to natural enzymes. However, nanozymes exist better stability than native enzymes, it can still maintain 85 % catalytic activity in strong acid and alkali (pH 2~10) or large temperature range (4~90°C). This provides conditions for designing complex catalytic systems. In this review, we discussed the enzymatic attributes and biomedical applications of gold nanoclusters, including peroxidase-like, catalase-like, detection of heavy metal ions, and therapy of brain and cancer etc. This review can help us understand the current research status nanozymes.

Bioactive silver phosphate/polyindole nanocomposites

Materials capable of releasing reactive oxygen species (ROS) can display antibacterial and anticancer activity, and may also have anti-oxidant capacity if they suppress intracellular ROS (e.g. nitric oxide, NO) resulting in anti-inflammatory activity. Herein we report silver phosphate (Ag₃PO₄)/polyindole (Pln) nanocomposites which display antibacterial, anticancer and anti-inflammatory activity, and have therefore potential for a variety of biomedical applications.

Materials capable of releasing reactive oxygen species (ROS) can display antibacterial and anticancer activity, and may also have antioxidant capacity if they suppress intracellular ROS (e.g. nitric oxide, NO) resulting in anti-inflammatory activity.

Se@SiO2@Au-PEG/DOX NCs as a multifunctional theranostic agent efficiently protect normal cells from oxidative damage during photothermal therapy

A multifunctional theranostic agent was exploited, which can efficiently prevent healthy cells from oxidative damage during photothermal therapy, thus solving the problem of hyperthermia therapy by introducing selenium.

Exploring the difference of bonding strength between silver(i) and chalcogenides in block copolymer systems

The order of Ag(i)–S < Ag(i)–Se < Ag(i)–Te bond strength was confirmed by single-molecule force spectroscopy (SMFS) with quantum chemical studies.

Diselenium-containing ultrathin polymer nanocapsules for highly efficient targeted drug delivery and combined anticancer effect

The combination of selenium and pillararenes to prepare selenium-containing pillararene-based biomaterials is of great significance for the development of biomedicine. Herein, using a covalent self-assembly strategy, we successfully developed new diselenium-containing ultrathin polymer nanocapsules based on lateral cross-linked pillararenes. The new system exhibited a very potent anticancer effect; additionally, the incorporation of the cleavable redox diselenium bond into the polymer nanocapsules provided a smart nanocarrier for drug delivery. Moreover, the polymer nanocapsules were developed for anticancer drug targeting delivery by loading an anticancer drug and introducing the tumor-penetrating peptide RGD through the host-guest interaction strategy. The targeting DOX-loaded diselenium-containing polymer nanocapsules exhibited enhanced stability, self-anticancer effect, targeted delivery and controlled drug release, resulting in effective combined inhibition of tumor progression.

One-pot cascade polymerization based on the addition reactions of electrophilic selenium reagents to alkenes

A direct polymerization based on the addition reactions of electrophilic selenium reagents to alkenes was established.

Synthesis of selenide-containing polymers by multicomponent polymerization based on γ-butyroselenolactone

A versatile protocol for the synthesis of various multiresponsive selenide-containing polymeric architectures was developed by multicomponent polymerization (MCP) of primary diamines, γ-butyroselenolactone and electrophilic reagents.

Toxicological responses of surfactant functionalized selenium nanoparticles: A quantitative multi-assay approach

The utilization of selenium nanomaterials (Se Nps) in material and biological science is quickly growing, crafting an imperative need for toxicological evaluation of the exposure prospective and environmental consequences of Se Nps. The combination of quantitative multi-assay approach into environmental toxicological analysis has provided novel opportunities to build up effective markers and scrutinize the means of venomous nature of Se Nps in the current study. In the present work, we analyzed the toxicological effect of bare and surface functionalized Se Nps by using multi assay viz. seed germination studies as a function of concentration of SeNps and by using antifungal assays. The influence of SeNps on bacterial activities were also investigated by using the S. aureus, E. coli, P. aeruginosa and S. typhi bacterial strains as widespread marker species for antibacterial studies. The ocular assessment of chlorophyll content was maximum for Brij coated Se NPs (98%) as compared to bare (20%), SDS (45%) and CTAB (38%) coated SeNps. The existence of chromosomal aberrations in root meristems of A. cepa(A. cepa) with computed MI values of 16, 25, 33 and 52% for bare, CTAB, SDS and Brij coated particles has indicated the genotoxic effects of SeNps. The biocompatible nature of Brij coated Se Nps was observed from the faster mobility of DNA in gel electrophoresis studies. The investigational studies in the current work appraise the toxicity and measure the competence of obtained data to characterize possibilities of probable threats, prominence of data requirement and breaches that must be filled to diminish the ambiguities about the safe use of Se Nps.

Organic selenium compounds as potential chemotherapeutic agents for improved cancer treatment

Selenium(Se)-containing compounds have attracted a growing interest as anticancer agents over recent decades, with mounting reports demonstrating their high efficacy and selectivity against cancer cells. Typically, Se compounds exert their cytotoxic effects by acting as pro-oxidants that alter cellular redox homeostasis. However, the precise intracellular targets, signalling pathways affected and mechanisms of cell death engaged following treatment vary with the chemical properties of the selenocompound and its metabolites, as well as the cancer model that is used. Naturally occurring organic Se compounds, besides encompassing a significant antitumor activity with an apparent ability to prevent metastasis, also seem to have fewer side effects and less systemic effects as reported for many inorganic Se compounds. On this basis, many novel organoselenium compounds have also been synthesized and examined as potential chemotherapeutic agents. This review aims to summarize the most well studied natural and synthetic organoselenium compounds and provide the most recent developments in our understanding of the molecular mechanisms that underlie their potential anticancer effects.

Controlled synthesis and size effects of multifunctional mesoporous silica nanosystem for precise cancer therapy

Nanomaterials-based drug delivery systems display potent applications in cancer therapy, owing to the enhanced permeability and retention effect and diversified chemical modification. In this study, we have tailored and synthesized different sized mesoporous silica nanoparticles (MSNs) through reactant control to investigate the relevancy of nanoparticle size toward anticancer efficacy and suppressing cancer multidrug resistance. The different sized MSNs loaded with anticancer ruthenium complex (RuPOP) and conjugated with folate acid (FA) to enhance the selectivity between cancer and normal cells. The nanosystem (Ru@MSNs) can specifically recognize HepG2 hepatocellular carcinoma cells, thus enhance accumulation and selective cellular uptake. The smaller sized (20 nm) Ru@MSNs exhibit higher anticancer activity against HepG2 cells, while the larger sized (80 nm) Ru@MSNs exhibit higher inhibitory effect against DOX-resistant hepatocellular carcinoma cells (R-HepG2). Moreover, Ru@MSNs induced ROS overproduction in cancer cells, leading to DNA damage and p53 phosphorylation, consequently promoting cancer cells apoptosis. Ru@MSNs (80 nm) also inhibited ABCB1 and ABCG2 expression in R-HepG2 cells to prevent drug efflux, thus overcome multidrug resistance. Ru@MSNs also inhibited tumor growth in vivo without obvious toxicity in major organs of tumor-bearing nude mice. Taken together, these results verify the size effects of MSNs nanosystem for precise cancer therapy.

Effect of Morphology and Concentration on Crossover between Antioxidant and Pro-oxidant Activity of MgO Nanostructures

The toxicity of nanomaterials can sometimes be attributed to photogenerated reactive oxygen species (ROS), but these ROS can also be scavenged by nanomaterials, yielding opportunities for crossover between the properties. The morphology of nanomaterials also influences such features due to defect-induced properties. Here we report morphology-induced crossover between pro-oxidant activity (ROS generation) and antioxidant activity (ROS scavenging) of MgO. To study this process in detail, we prepared three different nanostructures of MgO (nanoparticles, nanoplates, and nanorods) and characterized them by HRTEM. These three nanostructures effectively generate superoxide anions (O₂^•-) and hydroxyl radicals (^•OH) at higher concentrations (>500 μg/mL) but scavenge O₂^•- at lower concentrations (40 μg/mL) with successful crossover at 200 μg/mL. Nanorods of MgO generate the highest levels of O₂^•-, whereas nanoparticles scavenge O₂^•- to the highest extent (60%). Photoluminescence studies reveal that such crossover is based on the suppression of F²⁺ and the evolution of F⁺, F₂⁺, and F₂³⁺ defect centers. The evolution of these defect centers reflects the antibacterial activity of MgO nanostructures which is initiated at 200 μg/mL against Gram-positive S. aureus ATCC 29737 and among different bacterial strains including Gram-positive B. subtilis ATCC 6633 and M. luteus ATCC 10240 and Gram-negative E. coli ATCC K88 and K. pneumoniae ATCC 10031. Nanoparticles exhibited the highest antibacterial (92%) and antibiofilm activity (17%) against B. subtilis ATCC 6633 in the dark. Interestingly, the nitrogen-centered free radical DPPH is scavenged (100%) by nanoplates due to its large surface area (342.2 m²/g) and the presence of the F₂⁺ defect state. The concentration-dependent interaction with an antioxidant defense system (ascorbic acid (AA)) highlights nanoparticles as potent scavengers of O₂^•- in the dark. Thus, our findings establish guidelines for the selection of MgO nanostructures for diverse therapeutic applications.

Nano in nano: Biosynthesized gold and iron nanoclusters cargo neoplastic exosomes for cancer status biomarking

Timely detection is crucial for successful treatment of cancer. The current study describes a new approach that involves utilization of the tumor cell environment for bioimaging with in-situ biosynthesized nanoscale gold and iron probes and subsequent dissemination of Au-Fe nanoclusters from cargo exosomes within the circulatory system. We have isolated the Au-Fe cargo exosomes from the blood of the treated murine models after in situ biosyntheses from their respective pre-ionic solutions (HAuCl₄, FeCl₂), whereas Na₂SeO₃ supplementation added into Au lethal effect. The microarray data of various differentially expressed genes revealed the up-regulated tumor ablation and metal binding genes in SGC-7901 cell lines after treatment with Au-Fe-Se triplet ionic solution. The isolation of Au-Fe nanoclusters cargo exosomes (nano in nano) after secretion from deeply seated tumors may help in early diagnosis and reveal the tumor ablation status during and after the relevant treatment like radio-chemo therapies et al.

Gold-Based Medicine: A Paradigm Shift in Anti-Cancer Therapy?

A new era of metal-based drugs started in the 1960s, heralded by the discovery of potent platinum-based complexes, commencing with cisplatin [(H₃N)₂PtCl₂], which are effective anti-cancer chemotherapeutic drugs. While clinical applications of gold-based drugs largely relate to the treatment of rheumatoid arthritis, attention has turned to the investigation of the efficacy of gold(I) and gold(III) compounds for anti-cancer applications. This review article provides an account of the latest research conducted during the last decade or so on the development of gold compounds and their potential activities against several cancers as well as a summary of possible mechanisms of action/biological targets. The promising activities and increasing knowledge of gold-based drug metabolism ensures that continued efforts will be made to develop gold-based anti-cancer agents.

Se@SiO2-FA-CuS nanocomposites for targeted delivery of DOX and nano selenium in synergistic combination of chemo-photothermal therapy

In this study, a versatile tumor-targeted and multi-stimuli-responsive drug delivery vehicle (Se particle@porous silica-folic acid-copper sulfide/doxorubicin (Se@SiO₂-FA-CuS/DOX)) was fabricated for combined photothermal therapy with chemotherapy in cancer treatment. Due to excellent targeting ability, the Se@SiO₂-FA-CuS/DOX nanocomposites actively accumulated in tumor tissues and thus provided photothermal therapy under NIR irradiation and chemotherapy through the release of DOX and Se. Owing to the synergistic effect of chemotherapy (Se and DOX) and photothermal therapy, the Se@SiO₂-FA-CuS/DOX nanocomposites could efficiently inhibit cancer cells both in vitro and in vivo and even completely eliminate tumors. Moreover, as the toxicity of DOX could be reduced by Se, the treatment using Se@SiO₂-FA-CuS/DOX nanocomposites exhibited no appreciable adverse reactions. Thus, the Se@SiO₂-FA-CuS/DOX nanocomposites have great potential as a multifunctional nanoplatform in future clinical applications.

Smart Self-Assembled Nanosystem Based on Water-Soluble Pillararene and Rare-Earth-Doped Upconversion Nanoparticles for pH-Responsive Drug Delivery

Exploring novel drug delivery systems with good stability and new structure to integrate pillararene and upconversion nanoparticles (UCNPs) into one system continues to be an important challenge. Herein, we report a novel preparation of a supramolecular upconversion nanosystem via the host-guest complexation based on carboxylate-based pillar[5]arene (WP5) and 15-carboxy-N,N,N-trialkylpentadecan-1-ammonium bromide (1)-functionalized UCNPs to produce WP5⊃1-UCNPs that can be loaded with the chemotherapeutic drug doxorubicin (DOX). Importantly, the WP5 on the surface of the drug-loaded nanosystem can be efficiently protonated under acidic conditions, resulting in the collapse of the nanosystem and drug release. Moreover, cellular uptake confirms that the nanosystem can enter human cervical cancer (HeLa) cells, resulting in drug accumulation in the cells. More importantly, cytotoxicity experiments demonstrated the excellent biocompatibility of WP5⊃1-UCNPs without loading DOX and that the nanosystem DOX-WP5⊃1-UCNPs exhibited an ability of killing HeLa cells effectively. We also investigated magnetic resonance imaging and upconversion luminescence imaging, which may be employed as visual imaging agents in cancer diagnosis and treatment. Thus, in the present work, we show a simple yet powerful strategy to combine UCNPs and pillar[5]arene to produce a unified nanosystem for dual-mode bioimaging-guided therapeutic applications.

Tumor Catalytic-Photothermal Therapy with Yolk-Shell Gold@Carbon Nanozymes

Nanozymes, as a new generation of artificial enzymes, offer great opportunities in biomedical engineering and disease treatment. Synergizing the multiple intrinsic functions of nanozymes can improve their performance in biological systems. Here, we report a novel nanozyme with yolk-shell structure fabricated by combining a single gold nanoparticle core with a porous hollow carbon shell nanospheres (Au@HCNs). Au@HCNs exhibited enzyme-like activities similar to horseradish peroxidase and oxidase under an acidic environment, showing the ability of ROS generation. More importantly, the ROS production of Au@HCNs was significantly improved upon 808 nm light irradiation by the photothermal effect, which is often used for tumor therapy. Cellular and animal studies further demonstrated that the efficient tumor destruction was achieved through the combination of light-enhanced ROS and photothermal therapy. These results implied that the intrinsic enzyme-like activity and photothermal conversion of nanozymes can be synergized for efficient tumor treatment, providing a proof-of-concept of tumor catalytic-photothermal therapy based on nanozymes.

Au36(SePh)24 nanomolecules: synthesis, optical spectroscopy and theoretical analysis

Here, we report the synthesis of selenophenol (HSePh) protected Au₃₆(SePh)₂₄ nanomolecules via a ligand-exchange reaction of 4-tert-butylbenzenethiol (HSPh-tBu) protected Au₃₆(SPh-tBu)₂₄ with selenophenol, and its spectroscopic and theoretical analysis.

Chitosan nanoparticles loaded hydrogels promote skin wound healing through the modulation of reactive oxygen species

This study developed a novel bioactive chitosan nanoparticle loaded calcium alginate hydrogel to regulate inflammation and neovascularization for accelerated wound healing in vivo. It was found that chitosan nanoparticles loaded calcium alginate hydrogel exhibited remarkable antibacterial activity. Through the modulation of generation of ROS, it promoted the synthesis and secretion of IL-6 in vascular endothelial cell (VEC), suggesting its potential proinflammatory activation. Further, it promoted VEC invasion, metastasis and neovascularization to accelerate wound healing.

Inhibition of Thioredoxin Reductase by Targeted Selenopolymeric Nanocarriers Synergizes the Therapeutic Efficacy of Doxorubicin in MCF7 Human Breast Cancer Cells

Increasing evidence suggests selenium nanoparticles (Se NPs) as potential cancer therapeutic agents and emerging drug delivery carriers, yet, the molecular mechanism of their anticancer activity still remains unclear. Recent studies indicate thioredoxin reductase (TrxR), a selenoenzyme, as a promising target for anticancer therapy. The present study explored the TrxR inhibition efficacy of Se NPs as a plausible factor impeding tumor growth. Hyaluronic acid (HA)-functionalized selenopolymeric nanocarriers (Se@CMHA NPs) were designed wielding chemotherapeutic potential for target specific Doxorubicin (DOX) delivery. Se@CMHA nanocarriers are thoroughly characterized asserting their chemical and physical integrity and possess prolonged stability. DOX-loaded selenopolymeric nanocarriers (Se@CMHA-DOX NPs) exhibited enhanced cytotoxic potential toward human cancer cells compared to free DOX in an equivalent concentration eliciting its selectivity. In first-of-its-kind findings, selenium as Se NPs in these polymeric carriers progressively inhibit TrxR activity, further augmenting the anticancer efficacy of DOX through a synergistic interplay between DOX and Se NPs. Detailed molecular studies on MCF7 cells also established that upon exposure to Se@CMHA-DOX NPs, MCF7 cells endure G2/M cell cycle arrest and p53-mediated caspase-independent apoptosis. To gauge the relevance of the developed nanosystem in in vivo settings, three-dimensional tumor sphere model mimicking the overall tumor environment was also performed, and the results clearly depict the effectiveness of our nanocarriers in reducing tumor activity. These findings are reminiscent of the fact that our Se@CMHA-DOX NPs could be a viable modality for effective cancer chemotherapy.

The Epidemiology of Selenium and Human Cancer

The relation between selenium and cancer has been one of the most hotly debated topics in human health over the last decades. Early observational studies reported an inverse relation between selenium exposure and cancer risk. Subsequently, randomized controlled trials showed that selenium supplementation does not reduce the risk of cancer and may even increase it for some types, including advanced prostate cancer and skin cancer. An increased risk of diabetes has also been reported. These findings have been consistent in the most methodologically sound trials, suggesting that the early observational studies were misleading. Other studies have investigated selenium compounds as adjuvant therapy for cancer. Though there is currently insufficient evidence regarding the utility and safety of selenium compounds for such treatments, this issue is worthy of further investigation. The study of selenium and cancer is complicated by the existence of a diverse array of organic and inorganic selenium compounds, each with distinct biological properties, and this must be taken into consideration in the interpretation of both observational and experimental human studies.

Role of Surface Hydrophobicity of Dicationic Amphiphile-Stabilized Gold Nanoparticles on A549 Lung Cancer Cells

Herein, we report the surface functionality of dicationic cysteamine conjugated cholic acid (DCaC), dicationic cysteamine conjugated deoxycholic acid (DCaDC), and dicationic cysteamine conjugated lithocholic acid (DCaLC) templated gold nanoparticles (AuNPs) on mammalian cells. The haemocompatibility of the synthesized NPs was evaluated by in vitro hemolysis and erythrocyte sedimentation rate using human red blood cells (RBCs). In all of the systems, no toxicity was observed on human erythrocytes (RBCs) up to the concentration of 120 μg/mL. The anticancer activity of these dicationic amphiphile-stabilized AuNPs on A549 lung cancer cells was demonstrated by in vitro cell viability assay, intracellular reactive oxygen species estimation by DCFH-DA, apoptosis analysis using AO-EtBr fluorescence staining, DNA fragmentation analysis by agarose gel electrophoresis, and western blot analysis of caspase-3 expression. These results suggest that the cytotoxicity of AuNPs to A549 cells increase with the dose and hydrophobicity of amphiphiles and were found to be in the order: DCaLC-AuNPs > DCaDC-AuNPs > DCaC-AuNPs.

Selenium-Functionalized Graphene Oxide That Can Modulate the Balance of Reactive Oxygen Species

Graphene oxide (GO) is an important two-dimensional material since it is water-soluble and can be functionalized to adapt to different applications. However, the current covalent functionalization methods usually require hash conditions, long duration, and sometimes even multiple steps, while noncovalent functionalization is inevitably unstable, especially under a physiological environment where competing species exist. Diselenide bond is a dynamic covalent bond and can respond to both redox conditions and visible light irradiation in a sensitive manner. Thus, in this work by combining the stimuli response of diselenide bond and the oxidative/radical attackable nature of GO, we achieved the in situ covalent functionalization of GO simply by stirring GO with diselenide-containing molecules in aqueous solution. The covalent functionalization was proved by Fourier transform infrared, time-of-flight secondary ion mass spectrometry, atomic force microscopy, thermogravimetric analysis, and so forth, and the functionalization mechanism was deduced to involve both redox reaction and radical addition reaction according to the X-ray photoelectron spectrscopy, atomic emission spectroscopy, and Raman spectroscopy. Moreover, we modified GO with a biocompatible diselenide-containing polymer (mPEGSe)₂ and found selenium-functionalized GO could modulate the balance of reactive oxygen species (ROS). GOSe could decrease ROS level by accelerating the reduction of peroxides when the ROS concentration is high while boosting the ROS level by in situ generating ROS when its concentration is relatively low.

Diselenide-Containing Hyperbranched Polymer with Light-Induced Cytotoxicity

A light-induced cytotoxicity system was fabricated using active diselenide/porphyrin-containing hyperbranched polymer aggregates in aqueous solution through emulsification. When the nanoparticles were irradiated with visible light, ¹O₂ was produced by the porphyrin photosensitizers in the system, which cleaved the diselenide bonds in the polymer chains and disassembled the nanosystem. Interestingly, the oxidized products exhibited cytotoxicity to the MDA-MB 231cell line without using extra anticancer drugs, which endowed the system with potential visible light-induced antitumor activity. In combination with photodynamic therapy, it is greatly anticipated that better anticancer efficacy can be achieved with this system.