Construction of selenium-embedded mesoporous silica with improved antibacterial activity

Doxorubicin- and Selenium-Incorporated Mesoporous Silica Nanoparticles as a Combination Therapy for Osteosarcoma

Doxorubicin (Dox) is a promising anticancer chemotherapeutic, which has been widely investigated in osteosarcoma (OS) treatment. However, there are several disadvantages regarding its clinical use. Specifically, Dox has low specificity toward cancer cells, which can lead to serious side effects. In addition, cancer cells can develop resistance toward Dox, reducing its therapeutic efficiency. Combination therapy (CT) facilitated by nanoparticle delivery systems is a promising strategy to overcome these drawbacks. In this study, we investigated the effectiveness of Dox and selenium (Se) CT using mesoporous silica nanoparticles (MSN) coated with hyaluronic acid (HA) as drug carriers. We hypothesized that combining Se as a second agent can increase Dox anti-OS effectiveness and that MSN can be used to facilitate dual drug delivery. In our system, HA was used as a gatekeeper to control the intracellular release of Se/Dox by means of its pH-responsive degradation. CT therapy using MSNs coated with HA led to a higher OS inhibitory efficiency in vitro compared to MSNs carrying either Se or Dox alone. This study demonstrates that using MSNs for the dual delivery of Se and Dox is a promising method for OS therapy.

Surface-modified, zinc-incorporated mesoporous silica nanoparticles with improved antibacterial and rapid hemostatic properties

Severe bleeding and bacterial infections pose significant challenges to the global public health. Effective hemostatic materials have the potential to be used for rapid control of bleeding at the wound site. In this study, mesoporous silica nanoparticles (MSN) were doped with zinc ions (MSN@Zn) and subsequently functionalized with carboxyl (-COOH) groups through post-grafting, resulting in (MSN@Zn-COOH). The results demonstrated the successful functionalization of carboxyl groups on the surface of MSN@Zn mesoporous materials with minimal impact on the morphology. The released zinc ions showed potent antibacterial activity (above ∼80 %) against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). In vitro and in vivo assessments of MSN@Zn-COOH revealed excellent hemostatic effects and favorable blood compatibility. Hemolysis percentages associated with MSN@Zn-COOH exhibited noteworthy reductions in comparison to MSN. Furthermore, a decrease in APTT (a test evaluating the intrinsic coagulation pathway) of modified MSN@Zn indicated enhanced hemostasis, supported by their negative zeta potential (∼ -14 to -43 mV). Importantly, all samples showed no cytotoxicity. This work underscores the potential of MSN@Zn-COOH, with its combined hemostatic performance and antibacterial activity, for emergency clinical applications.

Superior doxorubicin cellular delivery effect established by optically active mesoporous silica nanoparticles

The impact of optically active biomaterials on drug delivery remains a vital and hot topic. To reveal special advantages of optically active mesoporous silica nanoparticles in delivering drug in cells, optically active mesoporous silica nanoparticles deliver doxorubicin (DOX) with chiral behavior in cancer cells was studied. The present work focused on two types of optically active mesoporous silica nanoparticles named as levorotatory optically active mesoporous silica nanoparticles (LOA-MSNs) and dextrorotatory optically active mesoporous silica nanoparticles (DOA-MSNs) and examined their effects on cellular DOX delivery in cancer cells. The obtained LOA-MSNs and DOA-MSNs were regular spheres with particle diameters ranging from 200 to 250 nm, and their shell layer was filled with interlaced channels. Our results indicated that LOA-MSNs and DOA-MSNs did not exhibit cytotoxicity towards MCF-7 cells and B16 cells. The cytotoxicity of DOX-loaded LOA-MSNs and DOX-loaded DOA-MSNs were stronger than DOX owing to the synergistic retention and accumulation effect of nanoparticles. More importantly, DOX-loaded DOA-MSNs presented stronger cytotoxicity due to the higher synergistic retention and accumulation effect of DOA-MSNs. These findings suggest that DOA-MSNs with superior cellular delivery of DOX have great potential to advance the development of optical anti-tumor delivery system.

Se-incorporated polycaprolactone spherical polyhedron enhanced vitamin B2 loading and prolonged release for potential application in proliferative skin disorders

Development of novel drug vehicles for vitamin B2 (VitB2) delivery is very important for designing controllable release system to improve epidermal growth and bone metabolism. In this work, selenium (Se)-incorporated polycaprolactone (PCL) spherical polyhedrons are successfully synthesized via a single emulsion solvent evaporation method which is utilized to load VitB2 to fabricate cell-responsive Se-PCL@VitB2 delivery systems. Their physicochemical properties are characterized by DLS, SEM, XRD, FTIR, and TGA-DSC. The release kinetics of VitB2 or Se from the samples are investigated in PBS solution (pH = 2.0, 5.0, 7.4, 8.0 and 12.0). The cytocompatibilities are also evaluated with normal BMSC and epidermal HaCat cells. Results exhibit that Se-PCL@VitB2 particles presents spherical polyhedral morphology (approximately (3.25 ± 0.46) μm), negative surface charge (-(54.03 ± 2.94) mV), reduced crystallinity and good degradability. Stability experiments imply that both VitB2 and Se might be uniformly dispersed in PCL matrix. And the incorporation of Se facilely promotes the loading of VitB2. The encapsulation efficiency and loading capacity are (98.42 ± 1.06)% and (76.25 ± 1.27) for Se-PCL@VitB2 sample. Importantly, it exhibits more prolonged release of both VitB2 and Se in neutral PBS solution (pH = 7.4) than other pH conditions. Presumably, the electrostatic interaction between Se, VitB2 and PCL contribute to its release mode. Cell experiments show that Se-PCL@VitB2 presents strong cytotoxicity to HaCat cells mainly due to the cytotoxic effect of Se anions and PCL degradation products. However, it exhibits weak inhibitory effect on BMSC cells. These note that the synthesized Se-PCL@VitB2 particles can be promising drug vehicles for potential application in epidermal proliferative disorders.

Mesoporous Oxidized Mn-Ca Nanoparticles as Potential Antimicrobial Agents for Wound Healing

Managing chronic non-healing wounds presents a significant clinical challenge due to their frequent bacterial infections. Mesoporous silica-based materials possess robust wound-healing capabilities attributed to their renowned antimicrobial properties. The current study details the advancement of mesoporous silicon-loaded MnO and CaO molecules (HMn-Ca) against bacterial infections and chronic non-healing wounds. HMn-Ca was synthesized by reducing manganese chloride and calcium chloride by urotropine solution with mesoporous silicon as the template, thereby transforming the manganese and calcium ions on the framework of mesoporous silicon. The developed HMn-Ca was investigated using scanning electron microscopy (SEM), transmission electron microscope (TEM), ultraviolet-visible (UV-visible), and visible spectrophotometry, followed by the determination of Zeta potential. The production of reactive oxygen species (ROS) was determined by using the 3,3,5,5-tetramethylbenzidine (TMB) oxidation reaction. The wound healing effectiveness of the synthesized HMn-Ca is evaluated in a bacterial-infected mouse model. The loading of MnO and CaO inside mesoporous silicon enhanced the generation of ROS and the capacity of bacterial capture, subsequently decomposing the bacterial membrane, leading to the puncturing of the bacterial membrane, followed by cellular demise. As a result, treatment with HMn-Ca could improve the healing of the bacterial-infected wound, illustrating a straightforward yet potent method for engineering nanozymes tailored for antibacterial therapy.

Biomimetic catheter surface with dual action NO-releasing and generating properties for enhanced antimicrobial efficacy

Infection of indwelling catheters is a common healthcare problem, resulting in higher morbidity and mortality. The vulnerable population reliant on catheters post-surgery for food and fluid intake, blood transfusion, or urinary incontinence or retention is susceptible to hospital-acquired infection originating from the very catheter. Bacterial adhesion on catheters can take place during the insertion or over time when catheters are used for an extended period. Nitric oxide-releasing materials have shown promise in exhibiting antibacterial properties without the risk of antibacterial resistance which can be an issue with conventional antibiotics. In this study, 1, 5, and 10 wt % selenium (Se) and 10 wt % S-nitrosoglutathione (GSNO)-incorporated catheters were prepared through a layer-by-layer dip-coating method to demonstrate NO-releasing and NO-generating capability of the catheters. The presence of Se on the catheter interface resulted in a 5 times higher NO flux in 10% Se-GSNO catheter through catalytic NO generation. A physiological level of NO release was observed from 10% Se-GSNO catheters for 5 d, along with an enhanced NO generation via the catalytic activity as Se was able to increase NO availability. The catheters were also found to be compatible and stable when subjected to sterilization and storage, even at room temperature. Additionally, the catheters showed a 97.02% and 93.24% reduction in the adhesion of clinically relevant strains of Escherichia coli and Staphylococcus aureus, respectively. Cytocompatibility testing of the catheter with 3T3 mouse fibroblast cells supports the material's biocompatibility. These findings from the study establish the proposed catheter as a prospective antibacterial material that can be translated into a clinical setting to combat catheter-related infections.

Selenium-incorporated mesoporous silica nanoparticles for osteosarcoma therapy

Selenium (Se) compounds are promising chemotherapeutics due to their ability to inhibit cancer cell activity via the generation of reactive oxygen species (ROS). However, to circumvent adverse effects on bone healthy cells, new methods are needed to allow intracellular Se delivery. Mesoporous silica nanoparticles (MSNs) are promising carriers for therapeutic ion delivery due to their biocompability, rapid uptake via endocytosis, and ability to efficiently incorporate ions within their tunable structure. With the aim of selectively inhibiting cancer cells, here we developed three types of MSNs and investigated their ability to deliver Se. Specifically, MSNs containing SeO32- loaded on the surface and in the pores (MSN-SeL), SeO32- doped in the silica matrix (Se-MSNs) and Se nanoparticles (SeNP) coated with mesoporous silica (SeNP-MSNs), were successfully synthesized. All synthesized nanoparticles were stable in neutral conditions but showed rapid Se release in the presence of glutathione (GSH) and nicotinamide adenine dinucleotide phosphate (NADPH). Furthermore, all nanoparticles were cytotoxic towards SaoS-2 cells and showed significantly lower toxicity towards healthy osteoblasts, where Se doped MSNs showed lowest toxicity towards osteoblasts. We further show that the nanoparticles could induce ROS and cell apoptosis. Here we demonstrate MSNs as promising Se delivery carriers for osteosarcoma (OS) therapy.

Synthesis and characterization of Se doped Fe3O4 nanoparticles for catalytic and biological properties

In this study, Se-doped Fe₃O₄ with antibacterial properties was synthesized using by a coprecipitation method. The chemistry and morphology of the Se doped Fe₃O₄ nanocomposite were characterized by energy-dispersive X-ray spectroscopy, field-emission scanning electron microscopy, X-ray diffraction, vibrating sample magnetometry, and Brunauer-Emmett-Teller spectroscopy. The antibacterial activity of the Fe₃O₄/Se nanocomposite was examined against G⁺ (Gram-positive) and G^- (Gram-negative) bacteria, in the order Staphylococcus aureus, Staphylococcus saprophyticus, Pseudomonas aeruginosa, Klebsiella pneumonia, and Escherichia coli, which are the most harmful and dangerous bacteria. Fe₃O₄/Se, as a heterogeneous catalyst, was successfully applied to the synthesis of pyrazolopyridine and its derivatives via a one-pot four-component reaction of ethyl acetoacetate, hydrazine hydrate, ammonium acetate, and various aromatic aldehydes. Fe₃O₄/Se was easily separated from the bacteria-containing solution using a magnet. Its admissible magnetic properties, crystalline structure, antibacterial activity, mild reaction conditions, and green synthesis are specific features that have led to the recommendation of the use of Fe₃O₄/Se in the water treatment field and medical applications. Direct Se doping of Fe₃O₄ was successfully realized without additional complicated procedures.

The application of mesoporous silica nanoparticles as a drug delivery vehicle in oral disease treatment

Mesoporous silica nanoparticles (MSNs) hold promise as safer and more effective medication delivery vehicles for treating oral disorders. As the drug's delivery system, MSNs adapt to effectively combine with a variety of medications to get over systemic toxicity and low solubility issues. MSNs, which operate as a common nanoplatform for the co-delivery of several compounds, increase therapy effectiveness and show promise in the fight against antibiotic resistance. MSNs offer a noninvasive and biocompatible platform for delivery that produces long-acting release by responding to minute stimuli in the cellular environmen. MSN-based drug delivery systems for the treatment of periodontitis, cancer, dentin hypersensitivity, and dental cavities have recently been developed as a result of recent unparalleled advancements. The applications of MSNs to be embellished by oral therapeutic agents in stomatology are discussed in this paper.

Construction of Selenium Nanoparticle-Loaded Mesoporous Silica Nanoparticles with Potential Antioxidant and Antitumor Activities as a Selenium Supplement

Excessive reactive oxygen species (ROS) can damage cells and affect normal cell functions, which are related to various diseases. Selenium nanoparticles are a potential selenium supplement for their good biocompatibility and antioxidant activity. However, their poor stability has become an obstacle for further applications. In this study, mesoporous silica nanoparticles (MSNs) were prepared as a carrier of selenium nanoparticles. Pluronic F68 (PF68) was used for the surface modification of the compounds to prevent the leakage of the selenium nanoparticles. The prepared MSN@Se@PF68 nanoparticles were characterized by transmission electron microscopy, energy-dispersive X-ray spectroscopy, dynamic light scattering, X-ray photoelectron spectroscopy, confocal micro-Raman spectroscopy, and Fourier transform infrared spectroscopy. The MSN@Se@PF68 nanoparticles showed excellent antioxidant activity in HeLa tumor cells and zebrafish larvae. The cytotoxicity of MSN@Se@PF68 nanoparticles was concentration- and time-dependent in HeLa tumor cells. The MSN@Se@PF68 nanoparticles showed a negligible cytotoxicity of ≤2 μg/mL at 48 h. At a concentration of 50 μg/mL, the cell viability of the HeLa tumor cells decreased to about 50%. The results indicated that the MSN@Se@PF68 nanoparticles could be a potential antitumor agent. The embryonic development of zebrafish cocultured with the MSN@Se@PF68 nanoparticles showed that there was no lethal or obvious teratogenic toxicity. The results implied that the MSN@Se@PF68 nanoparticles could be a safe selenium supplement and have the potential for antioxidant and antitumor activity.

Facile preparation of mesoporous silica coated nitrogen doped carbon dots for sensitive detection of picric acid

In this work, a nanocomposite suitable for long-term storage was constructed for efficient and highly selective detection of picric acid (PA). For this purpose, nitrogen-doped carbon dots (N-CDs) were synthesized by a simple hydrothermal reaction one-step method, and the synthesized nitrogen-doped carbon dots were loaded into amine-modified mesoporous silica nanoparticles (MSN-NH₂) to form N-CDs@MSN-NH₂ nanocomposites. The as-synthesized N-CDs@MSN-NH₂ was detected by X-ray photoelectron spectroscopy (XPS) and the Fourier transform infrared (FT-IR) analysis methods. After being coated with MSNs, the as-synthesized N-CDs@MSN-NH₂ exhibits excellent photo-stability in storage for 60 days at room temperature. Furthermore, PA can significantly quench the fluorescence signal of N-CDs@MSN-NH₂ through the fluorescence resonance energy transfer (FRET) effect, while other metal ions and nitro compounds only cause little change. The a-synthesized composites were used to detect PA with a detection limit of 50 nM in an aqueous solution. These results indicate that the synthesized composites have promise for application in PA detection in aqueous solution.

The construct of triple responsive nanocomposite and its antibacterial effect

The current serious mismatch between the increasing severity of bacterial infections and antibiotic production capacity urgently requires the emergence of novel antimicrobial materials. In this paper, dopamine methacrylamide (DMA) and N-isopropylacrylamide (NIPAM) were polymerized as the monomers into a block copolymer poly(dopamine methacrylamide-block-N-isopropylacrylamide) (P(DA-NIP)) and then encapsulated with polydopamine-coated magnetic nanoparticle clusters (MNC) to produce an antibacterial nanocomposite (MNC@P(DA-NIP)). This nanocomposite has triple responses respectively to light, heat and magnetism, which endow MNC@P(DA-NIP) with the abilities to kill bacteria effectively and capture/release bacteria conveniently. Under near-infrared (NIR) light irradiation, MNC@P(DA-NIP) could significantly elevate the temperature through photothermal conversion. The increased temperature favored both the capture of bacteria on MNC@P(DA-NIP), and the damage of bacterial cells, causing bacterial death almost completely. While low temperatures could promote the release of dead bacteria from the nanocomposites, might through the recovery of the hydrophilic state of the outlayer PNIPAM. Moreover, thanks to the magnetic responsibility, MNC@P(DA-NIP) could be easily separated from the bacterial cells and perform better biofilm penetration. The results showed that the antibacterial effect of MNC@P(DA-NIP) was 3.5 times higher than that of MNC, and the recycling capacity of MNC@P(DA-NIP) was better than MNC@PDA. What's more, MNC@P(DA-NIP) possessed the excellent anti-biofilm properties under magnetic field (MF) and NIR. The most important features of the triple-responsive nanocomposites are excellent antibacterial effect, good recyclability and easy preparation, which provide the nanocomposites with great potential in eliminating harmful bacterial cells.

Selenium Nanoparticles for Biomedical Applications: From Development and Characterization to Therapeutics

Selenium (Se) is an essential element to human health that can be obtained in nature through several sources. In the human body, it is incorporated into selenocysteine, an amino acid used to synthesize several selenoproteins, which have an active center usually dependent on the presence of Se. Although Se shows several beneficial properties in human health, it has also a narrow therapeutic window, and therefore the excessive intake of inorganic and organic Se-based compounds often leads to toxicity. Nanoparticles based on Se (SeNPs) are less toxic than inorganic and organic Se. They are both biocompatible and capable of effectively delivering combinations of payloads to specific cells following their functionalization with active targeting ligands. Herein, the main origin of Se intake, its role on the human body, and its primary biomedical applications are revised. Particular focus will be given to the main therapeutic targets that are explored for SeNPs in cancer therapies, discussing the different functionalization methodologies used to improve SeNPs stability, while enabling the extensive delivery of drug-loaded SeNP to tumor sites, thus avoiding off-target effects.

Recent advances in functionalized nanomaterials for the diagnosis and treatment of bacterial infections

The growing problem of resistant infections due to antibiotic misuse is a worldwide concern that poses a grave threat to healthcare systems. Thus, it is necessary to discover new strategies to combat infectious diseases. In this review, we provide a selective overview of recent advances in the use of nanocomposites as alternatives to antibiotics in antimicrobial treatments. Metals and metal oxide nanoparticles (NPs) have been associated with inorganic and organic supports to improve their antibacterial activity and stability as well as other properties. For successful antibiotic treatment, it is critical to achieve a high drug concentration at the infection site. In recent years, the development of stimuli-responsive systems has allowed the vectorization of antibiotics to the site of infection. These nanomaterials can be triggered by various mechanisms (such as changes in pH, light, magnetic fields, and the presence of bacterial enzymes); additionally, they can improve antibacterial efficacy and reduce side effects and microbial resistance. To this end, various types of modified polymers, lipids, and inorganic components (such as metals, silica, and graphene) have been developed. Applications of these nanocomposites in diverse fields ranging from food packaging, environment, and biomedical antimicrobial treatments to diagnosis and theranosis are discussed.

Silica Nanoparticles Disturb Ion Channels and Transmembrane Potentials of Cardiomyocytes and Induce Lethal Arrhythmias in Mice

Background

The toxicity of silica nanoparticles (SiNPs) on cardiac electrophysiology has seldom been evaluated.

Methods

Patch-clamp was used to investigate the acute effects of SiNP-100 (100 nm) and SiNP-20 (20 nm) on the transmembrane potentials (TMPs) and ion channels in cultured neonatal mouse ventricular myocytes. Calcium mobilization in vitro, cardiomyocyte ROS generation, and LDH leakage after exposure to SiNPs in vitro and in vivo were measured using a microplate reader. Surface electrocardiograms were recorded in adult mice to evaluate the arrhythmogenic effects of SiNPs in vivo. SiNP endocytosis was observed using transmission electron microscopy.

Results

Within 30 min, both SiNPs (10^-8-10^-6 g/mL) did not affect the resting potential and I_K1 channels. SiNP-100 increased the action potential amplitude (APA) and the I_Na current density, but SiNP-20 decreased APA and I_Na density. SiNP-100 prolonged the action potential duration (APD) and decreased the I_to current density, while SiNP-20 prolonged or shortened the APD, depending on exposure concentrations and increased I_to density. Both SiNPs (10^-6 g/mL) induced calcium mobilization but did not increase ROS and LDH levels and were not endocytosed within 10 min in cardiomyocytes in vitro. In vivo, SiNP-100 (4-10 mg/kg) and SiNP-20 (4-30 mg/kg) did not elevate myocardial ROS but increased LDH levels depending on dose and exposure time. The same higher dose of SiNPs (intravenously injected) induced tachyarrhythmias and lethal bradyarrhythmias within 90 min in adult mice.

Conclusion

SiNPs (i) exert rapid toxic effects on the TMPs of cardiomyocytes in vitro largely owing to their direct interfering effects on the I_Na and I_to channels and Ca²⁺ homeostasis but not I_K1 channels and ROS levels, and (ii) induce tachyarrhythmias and lethal bradyarrhythmias in vivo. SiNP-100 is more toxic than SiNP-20 on cardiac electrophysiology, and the toxicity mechanism is likely more complicated in vivo.