Bioaccessibility of chlorogenic acid and curcumin co-encapsulated in double emulsions with the inner interface stabilized by functionalized silica nanoparticles

The aim of this study was to evaluate the bioaccessibility of chlorogenic acid (CA) and curcumin co-encapsulated in Pickering double emulsions (DEs) with the inner interface stabilized by hydrophobically modified silica nanoparticles with myristic acid (SNPs-C14) or tocopherol succinate (SNPs-TS). Both SNPs-C14 and SNPs-TS showed contact angles > 90°. Pickering W1/O emulsions were formulated with 4 % of both types of SNPs. Pickering DEs showed higher creaming stability (5-7 %, day 42) and higher CA encapsulation efficiency (EE; 80 %) than control DE. The EE of curcumin was > 98 % in all the DEs. CA was steadily released from Pickering DEs during digestion, achieving bioaccessibility values of 58-60 %. Curcumin was released during the intestinal phase (∼80 % bioaccessibility in all DEs). Co-loaded DEs showed similar bioaccessibility for CA and curcumin than single-loaded. SNPs-C14 and SNPs-TS were suitable to stabilize the W1:O interface of DEs as co-delivery systems of bioactive compounds with health-promoting properties.

Protein coupled thionine acetate probed silica nanoparticles: An integrated laser-assisted therapeutic approach for treating cancer

Herein, we report a multifaceted nanoformulation, developed by binding thionine acetate (TA) in silica matrix to form TA loaded silica nanoparticles (STA Nps), which were characterized using various physicochemical techniques. STA NPs were spherical shaped having size 40-50 nm and exhibited good heating efficiency, improved photostability and singlet oxygen production rate than TA alone. In PDT experiment, the rate of degradation for ABDMA was enhanced from 0.1367 min-1 for TA alone to 0.1774 min-1 for STA Nps, depicting an increase in the reactive oxygen species (ROS) generation ability of STA Nps. Further, the cytotoxicity of STA Nps was investigated by carrying out the biophysical studies with Calf thymus DNA (Ct-DNA) and Human Serum Albumin (HSA). The results indicated that the binding of STA Nps to Ct-DNA causes alterations in the double helix structure of DNA and as a result, STA Nps can impart chemotherapeutic effects via targeting DNA. STA Nps showed good binding affinity with HSA without compromising the structure of HSA, which is important for STA Nps sustainable biodistribution and pharmacokinetics. Based on this study, it is suggested that because of the synergistic effect of chemo and phototherapy, STA Nps can be extensively utilized as potential candidates for treating cancer.

Targeting c-Myc with decoy oligodeoxynucleotide-loaded polycationic nanoparticles inhibits cell growth and induces apoptosis in cancer stem-like cells (NTERA-2)

BACKGROUND

An increase in cancer stem cell (CSC) populations and their resistance to common treatments could be a result of c-Myc dysregulations in certain cancer cells. In the current study, we investigated anticancer effects of c-Myc decoy ODNs loaded-poly (methacrylic acid-co-diallyl dimethyl ammonium chloride) (PMA-DDA)-coated silica nanoparticles as carriers on cancer-like stem cells (NTERA-2).

METHODS AND RESULTS

The physicochemical characteristics of the synthesized nanocomposites (SiO2@PMA-DDA-DEC) were analyzed using FT-IR, DLS, and SEM techniques. UV-Vis spectrophotometer was applied to analyze the release pattern of decoy ODNs from the nanocomposite. Furthermore, uptake, cell viability, apoptosis, and cell cycle assays were used to investigate the anticancer effects of nanocomposites loaded with c-Myc decoy ODNs on NTERA-2 cancer cells. The results of physicochemical analytics demonstrated that SiO2@PMA-DDA-DEC nanocomposites were successfully synthesized. The prepared nanocomposites were taken up by NTERA-2 cells with high efficiency, and could effectively inhibit cell growth and increase apoptosis rate in the treated cells compared to the control group. Moreover, SiO2@PMA-DDA nanocomposites loaded with c-Myc decoy ODNs induced cell cycle arrest at the G0/G1 phase in the treated cells.

CONCLUSIONS

The conclusion drawn from this study is that c-Myc decoy ODN-loaded SiO2@PMA-DDA nanocomposites can effectively inhibit cell growth and induce apoptosis in NTERA-2 cancer cells. Moreover, given that a metal core is incorporated into this synthetic nanocomposite, it could potentially be used in conjunction with irradiation as part of a decoy-radiotherapy combinational therapy in future investigations.

Prolonged delivery of HIV-1 vaccine nanoparticles from hydrogels

Immunization is a straightforward concept but remains for some pathogens like HIV-1 a challenge. Thus, new approaches towards increasing the efficacy of vaccines are required to turn the tide. There is increasing evidence that antigen exposure over several days to weeks induces a much stronger and more sustained immune response compared to traditional bolus injection, which usually leads to antigen elimination from the body within a couple of days. Therefore, we developed a poly(ethylene) glycol (PEG) hydrogel platform to investigate the principal feasibility of a sustained release of antigens to mimic natural infection kinetics. Eight-and four-armed PEG macromonomers of different MWs (10, 20, and 40 kDa) were end-group functionalized to allow for hydrogel formation via covalent cross-linking. An HIV-1 envelope (Env) antigen in its trimeric (Envtri) or monomeric (Envmono) form was applied. The soluble Env antigen was compared to a formulation of Env attached to silica nanoparticles (Env-SiNPs). The latter are known to have a higher immunogenicity compared to their soluble counterparts. Hydrogels were tunable regarding the rheological behavior allowing for different degradation times and release timeframes of Env-SiNPs over two to up to 50 days. Affinity measurements of the VCR01 antibody which specifically recognizes the CD4 binding site of Env, revealed that neither the integrity nor the functionality of Envmono-SiNPs (Kd = 2.1 ± 0.9 nM) and Envtri-SiNPs (Kd = 1.5 ± 1.3 nM), respectively, were impaired after release from the hydrogel (Kd before release: 2.1 ± 0.1 and 7.8 ± 5.3 nM, respectively). Finally, soluble Env and Env-SiNPs which are two physico-chemically distinct compounds, were co-delivered and shown to be sequentially released from one hydrogel which could be beneficial in terms of heterologous immunization or single dose vaccination. In summary, this study presents a tunable, versatile applicable, and effective delivery platform that could improve vaccination effectiveness also for other infectious diseases than HIV-1.

Silica nanoparticles alleviate the immunosuppression, oxidative stress, biochemical, behavioral, and histopathological alterations induced by Aeromonas veronii infection in African catfish (Clarias gariepinus)

In the aquaculture industry, silica nanoparticles (SiNPs) have great significance, mainly for confronting diseases. Therefore, the present study aims to assess the antibacterial efficiency of SiNPs as a versatile trial against Aeromonas veronii infection in African catfish (Clarias gariepinus). Further, we investigated the influence of SiNPs in palliating the immune-antioxidant stress biochemical, ethological, and histopathological alterations induced by A. veronii. The experiment was conducted for 10 days, and about 120 fish were distributed into four groups at random, with 30 fish each. The first group is a control that was neither exposed to infection nor SiNPs. The second group (SiNPs) was vulnerable to SiNPs at a concentration of 20 mg/L in water. The third group was experimentally infected with A. veronii at a concentration of 1.5 × 107 CFU/mL. The fourth group (A. veronii + SiNPs) was exposed to SiNPs and infected with A. veronii. Results outlined that A. veronii infection induced behavioral alterations and suppression of immune-antioxidant responses that appeared as a clear decline in protein profile indices, complement 3, lysozyme activity, glutathione peroxidase, and total antioxidant capacity. The kidney and liver function biomarkers (creatinine, urea, alkaline phosphatase, and alanine aminotransferase) and lipid peroxide (malondialdehyde) were substantially increased in the A. veronii group, with marked histopathological changes and immunohistochemical alterations in these tissues. Interestingly, the exposure to SiNPs resulted in a clear improvement in all measured biomarkers and a noticeable regeneration of the histopathological changes. Overall, it will establish that SiNPs are a new, successful tool for opposing immunological, antioxidant, physiological, and histopathological alterations induced by A. veronii infection.

Ferroptosis contributing to cardiomyocyte injury induced by silica nanoparticles via miR-125b-2-3p/HO-1 signaling

BACKGROUND

Amorphous silica nanoparticles (SiNPs) have been gradually proven to threaten cardiac health, but pathogenesis has not been fully elucidated. Ferroptosis is a newly defined form of programmed cell death that is implicated in myocardial diseases. Nevertheless, its role in the adverse cardiac effects of SiNPs has not been described.

RESULTS

We first reported the induction of cardiomyocyte ferroptosis by SiNPs in both in vivo and in vitro. The sub-chronic exposure to SiNPs through intratracheal instillation aroused myocardial injury, characterized by significant inflammatory infiltration and collagen hyperplasia, accompanied by elevated CK-MB and cTnT activities in serum. Meanwhile, the activation of myocardial ferroptosis by SiNPs was certified by the extensive iron overload, declined FTH1 and FTL, and lipid peroxidation. The correlation analysis among detected indexes hinted ferroptosis was responsible for the SiNPs-aroused myocardial injury. Further, in vitro tests, SiNPs triggered iron overload and lipid peroxidation in cardiomyocytes. Concomitantly, altered expressions of TfR, DMT1, FTH1, and FTL indicated dysregulated iron metabolism of cardiomyocytes upon SiNP stimuli. Also, shrinking mitochondria with ridge fracture and ruptured outer membrane were noticed. To note, the ferroptosis inhibitor Ferrostatin-1 could effectively alleviate SiNPs-induced iron overload, lipid peroxidation, and myocardial cytotoxicity. More importantly, the mechanistic investigations revealed miR-125b-2-3p-targeted HO-1 as a key player in the induction of ferroptosis by SiNPs, probably through regulating the intracellular iron metabolism to mediate iron overload and ensuing lipid peroxidation.

CONCLUSIONS

Our findings firstly underscored the fact that ferroptosis mediated by miR-125b-2-3p/HO-1 signaling was a contributor to SiNPs-induced myocardial injury, which could be of importance to elucidate the toxicity and provide new insights into the future safety applications of SiNPs-related nano products.

High biocompatible FITC-conjugated silica nanoparticles for cell labeling in both in vitro and in vivo models

Fluorescence nanosilica-based cell tracker has been explored and applied in cell biological research. However, the aggregation of these nanoparticles at physiological pH is still the main limitation. In this research, we introduced a novel fluorescence nano-based cell tracker suitable for application in live cells. The silica-coated fluorescein isothiocyanate isomer (FITC-SiO2) nanoparticles (NPs) were modified with carboxymethylsilanetriol disodium salt (FITC-SiO2-COOH), integrating the dianion form of FITC molecules. This nanosystem exhibited superior dispersion in aqueous solutions and effectively mitigated dye leakage. These labeled NPs displayed notable biocompatibility and minimal cytotoxicity in both in vitro and in vivo conditions. Significantly, the NPs did not have negative implications on cell migration or angiogenesis. They successfully penetrated primary fibroblasts, human umbilical vein endothelial cells and HeLa cells in both 2D and 3D cultures, with the fluorescence signal enduring for over 72 h. Furthermore, the NP signals were consistently observed in the developing gastrointestinal tract of live medaka fish larvae for extended periods during phases of subdued digestive activity, without manifesting any apparent acute toxicity. These results underscore the promising utility of FITC-SiO2-COOH NPs as advanced live cell trackers in biological research.

Silica nanoparticles conferring resistance to bacterial wilt in peanut (Arachis hypogaea L.)

Peanut bacterial wilt (PBW) caused by the pathogen Ralstonia solanacearum severely affects the growth and yield potential of peanut crop. In this study, we synthesized silica nanoparticles (SiO2 NPs), a prospective efficient management approach to control PBW, and conducted a hydroponic experiment to investigate the effects of different SiO2 NPs treatments (i.e., 0, 100, and 500 mg L-1 as NP0, NP100, and NP500, respectively) on promoting plant growth and resistance to R. solanacearum. Results indicated that the disease indices of NP100 and NP500 decreased by 51.5 % and 55.4 % as compared with NP0 under R. solanacearum inoculation, respectively, while the fresh and dry weights and shoot length of NP100 and NP500 increased by 7.62-42.05 %, 9.45-32.06 %, and 2.37-17.83 %, respectively. Furthermore, SiO2 NPs induced an improvement in physio-biochemical enzymes (superoxide dismutase, peroxidase, catalase, ascorbate peroxidase, and lipoxygenase) which eliminated the excess production of hydrogen peroxide, superoxide anions, and malondialdehyde to alleviate PBW stress. Notably, the targeted metabolomic analysis indicated that SiO2 NPs enhanced salicylic acid (SA) contents, which involved the induction of systemic acquired resistance (SAR). Moreover, the transcriptomic analysis revealed that SiO2 NPs modulated the expression of multiple transcription factors (TFs) involved in the hormone pathway, such as AHLs, and the identification of hormone pathways related to plant defense responses, such as the SA pathway, which activated SA-dependent defense mechanisms. Meanwhile, the up-regulated expression of the SA-metabolism gene, salicylate carboxymethyltransferase (SAMT), initiated SAR to promote PBW resistance. Overall, our findings revealed that SiO2 NPs, functioning as a plant elicitor, could effectively modulate physiological enzyme activities and enhance SA contents through the regulation of SA-metabolism genes to confer the PBW resistance in peanuts, which highlighted the potential of SiO2 NPs for sustainable agricultural practices.

Hybrid silica nanoparticles functionalized with pyrazolone-tethered organosilane: Synthesis and application for Sn (II) ion sensing in tap water

Pyrazolone tethered triazole functionalized organosilane and their hybrid silica nanoparticles (HSNPs) have been synthesised for the selective detection of Sn(II) using spectrophotometric techniques. The prepared compounds are characterized by FT-IR, NMR (1H and 13C), XRD, mass spectrometry and FE-SEM spectral analyses. The synthesized hybrid silica nanoparticles gave improved detection limit of 4.3 × 10-8 M and stoichiometry of complex between analyte and probe was found to be 1:1. The association constant calculated for organosilane and their HSNPs came out to be 9.54 × 104 M-1 and 7.47 × 104 M-1 while the presence of other ions showed no interference in the sensing behaviour. The results of the use of this sensing system in tap water facilitate its applicability in real samples with the recovery % more than 98.

Adsorption optimization and modeling of Hg2+ ions from aqueous solutions using response surface methodology by SNPs-CS bionanocomposite produced from rice husk agro-industrial waste as a novel environmentally-friendly bionanoadsorbent

In the present research, extraction of silica (SiO2) from rice husk (RH) was optimized and silica nanoparticles (SNPs) was produced using it and functionalized by chitosan (CS) functional groups to obtain CS functionalized SNPs (SNPs-CS) bionanocomposite for the first time. The physical and chemical characteristics of the produced materials were examined using structural analyses. The results of structural analyses confirmed the fine structure of the produced materials. The SNPs-CS bionanocomposite was applied to effectively remove Hg2+ ions from aqueous solutions as an environmentally-friendly bionanoadsorbent and optimization and modeling of the adsorption conditions was explored using designed experiments by Design-Expert software with central composite design (CCD) and response surface methodology (RSM). Optimum adsorption conditions were obtained as solution pH of 6, SNPs-CS dosage of 0.1 g L-1 and Hg2+ ions concentration of 100 mg L-1 by removal efficiency of 85% and desirability function of 0.876. The results of adsorption kinetic showed a better fit of the pseudo-second-order model with experimental data, indicating the chemisorption of the adsorption process. The better fit of the Langmuir model with experimental data was confirmed by the results of adsorption isotherms, demonstrating monolayer adsorption on the homogeneous surface. The adsorption thermodynamic results illustrated the exothermicity and spontaneity of the adsorption reaction. The results of SNPs-CS recovery depicted its excellent recovery ability of removal efficiency with more than 90% after five consecutive adsorption and desorption cycles, which proved high potential of the produced bionanocomposite for industrial applications.

Enhancing photodynamic therapy efficacy through silica nanoparticle-mediated delivery of temoporfin for targeted in vitro breast cancer treatment

Photodynamic therapy (PDT), an approach to cancer treatment, relies fundamentally on two key elements: a light source and a photosensitizing agent. A primary challenge in PDT is the efficient delivery of photosensitizers to the target tissue, hindered by the body's reticuloendothelial system (RES). Silica nanoparticles (SiNPs), known for their unique properties, emerge as ideal carriers in this context. In this study, SiNPs are utilized to encapsulate Temoporfin, a photosensitizer, aiming to enhance its delivery and reduce toxicity, particularly for treating MCF-7 cancer cells in vitro. The synthesized SiNPs were meticulously characterized by their size and shape using Transmission Electron Microscopy (TEM). The study also involved evaluating the cytotoxicity of both encapsulated and naked Temoporfin across various concentrations. The objective was to determine the ideal concentration and exposure duration using red laser light (intensity approximately 110 mW/cm2) to effectively eradicate MCF-7 cells. The findings revealed that Temoporfin, when encapsulated in SiNPs, demonstrated significantly greater effectiveness compared to its naked form, with notable improvements in concentration efficiency (50 %) and exposure time efficiency (76.6 %). This research not only confirms the superior effectiveness of encapsulated Temoporfin in eliminating cancer cells but also highlights the potential of SiNPs as an efficient drug delivery system in photodynamic therapy. This sets the groundwork for more advanced strategies in cancer treatment.

Silica/Annona muricata nano-hybrid: Synthesis and anticancer activity against breast cancer

Biogenically derived silica nanoparticles may serve as a well-defined target vehicle for drug delivery and have a wide range of applications in biomedicine. Silica nanoparticles are an excellent candidate as drug carriers due to their mesoporous structure, high drug loading capacity, low toxicity, environmental friendliness and low economic synthesis procedures. In this study, nano structured silica was extracted from sugarcane bagasse through an alkali leaching extraction and conjugated with A. muricata extract overcoming its poor solubility and improving its bioavailability within the host system. The Silica Nanoparticles (SNP) and Annona muricata conjugated Silica Nanoparticles (AM/SNP) were characterized using SEM, FTIR, TGA, EDAX, XRD and zeta potential. The AM/SNP was subjected to kinetic release studies and exhibited a sustained release of 64 % over the course of 12 h in contrast to extract, indicating the slow release of the drug under synthetic conditions. A. muricata pose a high affinity against tumor cells as an anti-cancer agent, and the potential of binding was testified using in-silico virtual screening against breast cancer receptors with lead acetogenins with Annomuricin (-7.4 kcal/mol) and Gigantecin (-7.4 kcal/mol) exhibiting a high binding affinity against ER and HER2+ receptors respectively. The AM/SNP conjugate exhibited high cytotoxicity against the MCF-7 breast cancer cell line with an IC50 value of 33.43 μg, indicating high potency of the conjugate at low concentrations, facilitating low systemic toxicity on administration.

Stimuli-responsive biodegradable silica nanoparticles: From native structure designs to biological applications

Due to their inherent advantages, silica nanoparticles (SiNPs) have greatly potential applications as bioactive materials in biosensors/biomedicine. However, the long-term and nonspecific accumulation in healthy tissues may give rise to toxicity, thereby impeding their widespread clinical application. Hence, it is imperative and noteworthy to develop biodegradable and clearable SiNPs for biomedical purposes. Recently, the design of multi-stimuli responsive SiNPs to improve degradation efficiency under specific pathological conditions has increased their clinical trial potential as theranostic nanoplatform. This review comprehensively summaries the rational design and recent progress of biodegradable SiNPs under various internal and external stimuli for rapid in vivo degradation and clearance. In addition, the factors that affect the biodegradation of SiNPs are also discussed. We believe that this systematic review will offer profound stimulus and timely guide for further research in the field of SiNP-based nanosensors/nanomedicine.

Assessment of metabolic responses following silica nanoparticles in zebrafish models using 1H NMR analysis

Silica nanoparticles (SNPs) are widely explored as drug carriers, gene delivery vehicles, and as nanoparticles intended for bone and tissue engineering. SNPs are highly evident through various clinical trials for a wide range of biomedical applications. SNPs are biocompatible and promising nanoparticles for next-generation therapeutics. However, despite the well-established importance of SNPs, metabolomics methods for the SNPs remain elusive which renders its maximal clinical translation. We applied 1H nuclear magnetic resonance (1H NMR) spectroscopy to investigate the metabolomics profile in Zebrafish (Danio rerio) exposed to SNPs. Zebrafish were exposed to the SNPs (10.0, 25.0, and 50.0 μg/mL) for 72 h and whole-body samples were subjected for targeted profiling. Pattern recognition of 1H NMR spectral data depicted alterations in the metabolomic profiles between control and SNPs exposed zebrafish. We found that tryptophane, lysine, methionine, phenylalanine, tyrosine, sn-glycero-3-phosphocholine (G3PC), and o-phosphocholine were decreased. The metabolic expression of niacinamide, nicotinamide adenine dinucleotide (NAD+), citrate, adenosine triphosphate (ATP), and xanthine were increased in zebrafish with SNPs treatment. We are report for the first time on metabolite alterations and phenotypic expression in zebrafish via 1H NMR. These results demonstrate that SNPs can adversely affect the significant metabolic pathways involved in energy, amino acids, cellular membrane, lipids, and fatty acid metabolisms. Metabolomics profiling may be able to detect metabolic dysregulation in SNPs-treated zebrafish and establish a foundation for further toxicological studies.

Ratiometric electrogenerated chemiluminescence sensing microRNA based on electrochemically controlled release of lucigenin from silica/chitosan/lucigenin nanoparticles

The dye-doped silica nanoparticles-based electrogenerated chemiluminescence (ECL) has been widely explored for analytical purposes due to its high sensitivity, simplicity and wide dynamic concentration range. However, only a few of dye molecules located at the near surface of nanoparticles can participate in the ECL reaction due to the poor conductivity of silica nano-matrix. In addition, the ECL signal is easy to be affected by environmental interference, which results in poor accuracy. Herein, a ratiometric ECL sensing method is established based on the electrochemically controlled release of lucigenin molecules from silica/chitosan/lucigenin composite nanoparticles (Lu/CS NPs) with the aid of sulfide ions. Firstly, H+ produced from the electrochemical oxidation of HS- ions can combine with SiO- and displace lucigenin from Lu/CS NPs. The released lucigenin molecules react with the reactive oxygen species (ROS) generated from the electroreduction of dissolved oxygen to produce the cathodic ECL signal. In addition, the excited elemental sulfur from the electrooxidation of HS- ions transfers its energy to lucigenin molecules and makes them be excited to produce energy-transfer anodic ECL signal. Based on these findings, a ratiometric ECL sensor is developed taking the anodic ECL intensity of lucigenin as a reference signal for the cathodic ECL of lucigenin. The proposed ratiometric ECL sensor has been successfully applied to the detection of let-7a with a wide linear range of 0.1-9.0 pM, a low detection limit of 28 fM, high selectivity and good reproducibility. Moreover, the developed approach was used to detect let-7a in human serum composite samples with good recoveries.

Eco-friendly electrochemical sensor for determination of conscious sedating drug "midazolam'' based on Au-NPs@Silica modified carbon paste electrode

Benzodiazepines (BZDs) are a group of drugs prescribed for their sedating effect. Their misuse and addictive properties stipulate different authorities for developing simple, fast and accurate analytical methods for instantaneous detection. Differential pulse voltammetric technique (DPV) was utilized for the selective assay of midazolam hydrochloride (MDZ) in the pure, parenteral dosage forms and plasma samples. A chemically modified carbon paste electrode (CPE) was implemented during the study. The method depended on the electroreduction of MDZ on the surface of the electrode over a potential range of 0.0 V to -1.6 V. The electrode was fabricated using silica nanoparticles (Si-NPs) which were incorporated into the composition of the CPE and used to enhance the electrode performance. Then, to enhance the sensitivity of the method, a chronoamperometric modification step was applied for depositing gold nanoparticles (Au-NPs) on the carbon paste electrode surface. Modification with Au-NPs showed a higher reduction current peak for MDZ with well-defined peaks. Various parameters such as pH of the media and measurements scan rate were investigated and optimized to enhance the sensor sensitivity. The sensor showed a dynamic linear response over a concentration range of 4.0 × 10-7 M to 2.9 × 10-4 M of MDZ with a LOD of 2.24 × 10-8 M using 0.1 M acetate buffer (pH 5.6). The sensor was validated in accordance with the ICH guidelines regarding accuracy, precision and specificity for the selective assay of MDZ in the presence of excipients. A greenness evaluation was performed using three different assessment tools, namely, the "Green Analytical Procedure Index" (GAPI), the "Analytical Greenness metric" (AGREE) and the "Whiteness Analytical Chemistry tool" (WAC) using the RGB12 model.

Silica nanoparticles induce ferroptosis of HUVECs by triggering NCOA4-mediated ferritinophagy

Silica nanoparticles (SiNPs) have been widely used in electronics, chemistry, and biomedicine. Human exposure to SiNPs and possible health effects have attracted much attention. The potential cardiovascular toxicity of SiNPs and their related mechanisms are still unclear. Therefore, in this study, we investigated the toxic effects of SiNPs on human umbilical vein endothelial cells (HUVECs). We found that SiNPs could induce HUVECs ferroptosis. The results showed that the level of intracellular divalent iron and lipid peroxidation increased, and mitochondrial cristae decreased. In addition, the pretreatment of the iron chelator deferoxamine mesylate (DFO) could alleviate the ferroptosis of cells. Interestingly, pretreatment of 3-methyladenine (3-MA), an autophagy/PI3K inhibitor could partially inhibit autophagy and reduce ferroptosis, which indicated that autophagy played an important role in cell ferroptosis. Additionally, after knocking down nuclear receptor coactivator 4 (NCOA4), Ferritin Heavy Chain 1 (FTH1) expression was up-regulated, and the levels of divalent iron and lipid peroxidation decreased, which suggested that NCOA4 mediated the ferroptosis of HUVECs induced by SiNPs. In conclusion, this study shows that SiNPs can induce cardiovascular toxicity in which there is ferroptosis. NCOA4-mediated ferritinophagy and resultant ferroptosis by SiNPs may play an important role. This study provides a new theoretical strategy for the treatment and prevention of cardiovascular diseases in the future.

Bioinformatics-driven discovery of silica nanoparticles induces apoptosis and renal damage via the unfolded protein response in NRK-52E cells and rat kidney

Silica nanoparticles (SiNPs) are nanomaterials with widespread applications in drug delivery and disease diagnosis. Despite their utility, SiNPs can cause chronic kidney disease, hindering their clinical translation. The molecular mechanisms underlying SiNP-induced renal toxicity are complex and require further investigation. To address this challenge, we employed bioinformatics tools to predict the potential mechanisms underlying renal damage caused by SiNPs. We identified 1627 upregulated differentially expressed genes (DEGs) and 1334 downregulated DEGs. Functional enrichment analysis and protein-protein interaction network revealed that SiNP-induced renal damage is associated with apoptosis. Subsequently, we verified that SiNPs induced apoptosis in an in vitro model of NRK-52E cells via the unfolded protein response (UPR) in a dose-dependent manner. Furthermore, in an in vivo rat model, high-dose SiNP administration via tracheal drip caused hyalinization of the renal tubules, renal interstitial lymphocytic infiltration, and collagen fiber accumulation. Concurrently, we observed an increase in UPR-related protein levels at the onset of renal damage. Thus, our study confirmed that SiNPs induce apoptosis and renal damage through the UPR, adding to the theoretical understanding of SiNP-related kidney damage and offering a potential target for preventing and treating kidney injuries in SiNP clinical applications.

A Simple Aptamer-Based Nanoconjugate Assay for Diagnosis of Chronic Myeloid Leukemia

Chronic myeloid leukemia (CML) as a bone marrow stem cell clonal disease appears from the proliferation of granulocyte cells at all stages of maturation. If the disease diagnosis is not early, patients enter the blastic phase, which decreases their survival rate to 3-6 months. It implies the significance of the early diagnosis of CML. In this study, we introduce a simple array for diagnosis of the K562 cells as the human immortalized myeloid leukemia cell line. The developed aptamer-based biosensor (aptasensor) includes the T2-KK1B10 aptamer strands attached to the surface of mesoporous silica nanoparticles (MSNPs) with the cavities accumulated from rhodamine B and coated by both Ca2+ ions and ATP aptamer. The aptamer-based nanoconjugate can enter the K562 cells through the complexation of the T2-KK1B10 aptamer with the cells. The ATP in the cells and low level of intracellular Ca2+ ion release both the aptamer and ion from the surface of the MSNPs. The liberated rhodamine B results in an increased fluorescence intensity. Fluorescence microscope imaging and flow cytometry histogram display a strong fluorescence emission for the K562 cells (CML cells) exposed to the nanoconjugate in comparison with that for MCF-7 cells. The aptasensor possesses good performance in the blood samples with the advantages of high sensitivity, rapidness, and cost-effectiveness, making it an appropriate tool for the diagnosis of CML disease.

Glycopolymer-grafted nanoparticles as glycosaminoglycan mimics with cell proliferation and anti-tumor metastasis activities

Glycosaminoglycans (GAGs) are naturally existing extracellular components with a variety important biological functions. However, their heterogeneous chemical compositions and the challenges in purification have become the main disadvantages for clinical applications. Thus, various synthetic glycopolymers have been designed to mimic the structures and functions of natural GAGs. In the current study, glycopolymers from structurally simple glucose or N-acetylglucosamine monomers were synthesized, which were further subjected to sulfation of different degrees and grafting onto silica nanoparticles, leading to spherical-shaped nano-structures of uniform diameters. With the successively strengthened multivalent effect, the obtained glycopolymer nanoparticles not only showed excellent effects on promotion of cell proliferation by stabilizing growth factors, but also significantly inhibited tumor metastasis by weakening the adhesion between tumor cells and activated platelets. Among the prepared nanoparticles, S3-PGNAc@Si with N-acetylglucosamine segment and the highest sulfation degree exhibited the strongest bioactivities, which were even close to those of heparin. This work presents a novel approach for structural and functional mimicking of natural GAGs from simple and low-cost monosaccharides, holding great potential for a range of biomedical applications.

Fluorescent silica nanoparticles as nano-chemosensors for the sequential detection of Pb2+ ions and bacterial-spore biomarker dipicolinic acid (DPA) in aqueous solution

Herein, we report fluorescein-labelled silica nanoparticles (FSNP) which serve as fluorescent nano-chemosensors for sequential detection of Pb2+ (which is a toxic heavy metal) and dipicolinic acid (DPA) (which is a distinctive indicator biomarker of bacterial spores) with high sensitivity and selectivity. The fluorescence of FSNP is quenched because of the complex formation between Pb2+ ions and surface amide groups, however, the fluorescence is recovered in contact with DPA, resulting from the association of DPA with surface bound Pb2+ ions. FSNP-Pb2+ complexes show high sensitivity towards DPA with a low detection limit of 850 nM which is approximately seventy times lower than the infectious dosage of bacterial spores (60 μM). Lateral flow test platform was further developed to show the applicability and practicability of our system.

Polymeric nanocomposite hydrogel scaffold for jawbone regeneration: The role of rosuvastatin calcium-loaded silica nanoparticles

Bones are subject to different types of damages ranging from simple fatigue to profound defects. In serious cases, the endogenous healing mechanism is not capable of healing the damage or restoring the normal structure and function of the bony tissue. The aim of this research was to achieve a sustained delivery of rosuvastatin and assess its efficacy in healing bone tissue damage. Rosuvastatin was entrapped into silica nanoparticles and the system was loaded into an alginate hydrogel to be implanted in the damaged tissue. Silica nanoparticles were formulated based on a modified Stöber technique and alginate hydrogel was prepared via sprinkling alginate onto silica nanoparticle dispersion followed by addition of CaCl2 to promote crosslinking and hydrogel rigidification. The selected nanoparticle formulation possessed high % drug content (100.22± 0.67%), the smallest particle size (221.00± 7.30 nm) and a sustained drug release up to 4 weeks (98.72± 0.52%). The fabricated hydrogel exhibited a further delay in drug release (81.52± 4.81% after 4 weeks). FT-IR indicated the silica nanoparticle formation and hydrogel crosslinking. SEM visualized the porous and dense surface of hydrogel. In-vivo testing on induced bone defects in New Zealand rabbits revealed the enhanced rate of new bone tissue formation, its homogeneity in color as well as similarity in structure to the original tissue.

Methods for the Preparation of Silica and Its Nanoparticles from Different Natural Sources

Silica (SiO2), a component of the earth's crust, has been in use for many nanotechnological applications. This review presents one of the newest methods for safer, more affordable, and more ecologically friendly production of silica and its nanoparticles from the ashes of agricultural wastes. The production of SiO2 nanoparticles (SiO2NPs) from different agricultural wastes, including rice husk, rice straw, maize cobs, and bagasse, was systematically and critically discussed. The review also emphasizes current issues and possibilities linked with contemporary technology to raise awareness and stimulate scholars' insight. Furthermore, the processes involved in isolating silica from agricultural wastes were explored in this work.

C5a/C5aR1 axis as a key driver promotes epithelial-to-mesenchymal transition in airway epithelial cells in silica nanoparticles-induced pulmonary fibrosis

Previous studies have shown that silica nanoparticles (SiNPs) exposure can affect the respiratory, cardiovascular, reproductive and other systems, with the lung being the primary target organ for the direct effect, causing damage with a central feature of pulmonary inflammation and fibrosis. However, the underlying mechanisms of pulmonary fibrosis due to SiNPs are not fully understood. The aim of the study was to investigate the role of complement anaphylatoxin C5a in SiNPs-induced pulmonary fibrosis. A mouse model of SiNPs-induced pulmonary fibrosis was established, and pulmonary fibrosis-related indicators, epithelial-to-mesenchymal transition (EMT), C5a/C5aR1 and high mobility group protein B1 (HMGB1) proteins were measured. An in vitro study using the human lung epithelial cell line BEAS-2B investigated whether C5a leads to epithelial-to-mesenchymal trans-differentiation. In vivo studies revealed that SiNPs-induced pulmonary fibrosis mainly manifested as EMT trans-differentiation in airway epithelial cells, which subsequently led to excessive deposition of extracellular matrix (ECM). Furthermore, we found that C5a and C5aR1 proteins were also increased in SiNPs-induced pulmonary fibrosis tissue. In vitro studies also showed that C5a directly activated HMGB1/RAGE signaling and induced EMT in BEAS-2B cells. Finally, treatment of SiNPs-exposed mice with the C5aR1 inhibitor PMX205 effectively reduced C5aR1 levels and inhibited the activation of HMGB1/RAGE signaling and the expression of EMT-related proteins, culminating in a significant alleviation of pulmonary fibrosis. Taken together, our results suggest that C5a/C5aR1 is the main signaling pathway for SiNPs-induced pulmonary fibrosis, which induces EMT in airway epithelial cells via the HMGB1/RAGE axis.

A new solid phase extraction sorbent developed based on cyanopropyl functionalized silica nanoparticles for organophosphorus pesticides determination

In this work, a simple sol-gel approach was used for the preparation of cyanopropyl (CNPr) functionalized silica nanoparticles (SiO2-CNPr) that tetraethoxysilane (TEOS) and cyanopropyltriethoxysilane (CNPrTEOS) used as precursors. This as-prepared SiO2-CNPr nanoparticle sorbent was first characterized using FESEM, EDX, FTIR, TGA, and BET techniques. Then, the SiO2-CNPr nanoparticle was applied as a new SPE sorbent for determining trace levels of OPPs in environmental water samples. To enhance the simultaneous extraction of non-polar or/and polar OPPs and to obtain the most efficient sorbent, several sol-gel synthesis parameters were studied. In addition, the effect of several effective parameters on SPE performance was investigated toward simultaneous extraction of non-polar or/and polar OPPs. Moreover, the figures of merit such as precision, linearity, LOQ, LOD, and recovery were evaluated for the sorbent. Finally, the designed SiO2-CNPr SPE was used to determine OPPs in real water samples, and its extraction performance was compared to commercial cartridges based on cyanopropyl.

Silica nanoparticles: A review of their safety and current strategies to overcome biological barriers

Silica nanoparticles (SNP) have gained tremendous attention in the recent decades. They have been used in many different biomedical fields including diagnosis, biosensing and drug delivery. Medical uses of SNP for anti-cancer, anti-microbial and theranostic applications are especially prominent due to their exceptional performance to deliver many different small molecules and recently biologics (mRNA, siRNA, antigens, antibodies, proteins, and peptides) at targeted sites. The physical and chemical properties of SNP such as large specific surface area, tuneable particle size and porosity, excellent biodegradability and biocompatibility make them an ideal drug delivery and diagnostic platform. Based on the available data and the pre-clinical performance of SNP, recent interest has driven these innovative materials towards clinical application with many of the formulations already in Phase I and Phase II trials. Herein, the progress of SNP in biomedical field is reviewed, and their safety aspects are analysed. Importantly, we critically evaluate the key structural characteristics of SNP to overcome different biological barriers including the blood-brain barrier (BBB), skin, tumour barrier and mucosal barrier. Future directions, potential pathways, and target areas towards rapid clinical translation of SNP are also recommended.

Prospects and hazards of silica nanoparticles: Biological impacts and implicated mechanisms

With the thrive of nanotechnology, silica nanoparticles (SiNPs) have been extensively adopted in the agriculture, food, cosmetic, and even biomedical industries. Due to the mass production and use, SiNPs inevitably entered the environment, resulting in ecological toxicity and even posing a threat to human health. Although considerable investigations have been conducted to assess the toxicity of SiNPs, the correlation between SiNPs exposure and consequent health risks remains ambiguous. Since the biological impacts of SiNPs can differ from their design and application, the toxicity assessment for SiNPs may be extremely difficult. This review discussed the application of SiNPs in different fields, especially their biomedical use, and documented their potential release pathways into the environment. Meanwhile, the current process of assessing SiNPs-related toxicity on various model organisms and cell lines was also detailed, thus estimating the health threats posed by SiNPs exposure. Finally, the potential toxic mechanisms of SiNPs were also elaborated based on results obtained from both in vivo and in vitro trials. This review generally summarizes the biological effects of SiNPs, which will build up a comprehensive perspective of the application and toxicity of SiNPs.

Immunogenicity of a silica nanoparticle-based SARS-CoV-2 vaccine in mice

Safe and effective vaccines have been regarded early on as critical in combating the COVID-19 pandemic. Among the deployed vaccine platforms, subunit vaccines have a particularly good safety profile but may suffer from a lower immunogenicity compared to mRNA based or viral vector vaccines. In fact, this phenomenon has also been observed for SARS-CoV-2 subunit vaccines comprising the receptor-binding domain (RBD) of the spike (S) protein. Therefore, RBD-based vaccines have to rely on additional measures to enhance the immune response. It is well accepted that displaying antigens on nanoparticles can improve the quantity and quality of vaccine-mediated both humoral and cell-mediated immune responses. Based on this, we hypothesized that SARS-CoV-2 RBD as immunogen would benefit from being presented to the immune system via silica nanoparticles (SiNPs). Herein we describe the preparation, in vitro characterization, antigenicity and in vivo immunogenicity of SiNPs decorated with properly oriented RBD in mice. We found our RBD-SiNP conjugates show narrow, homogeneous particle distribution with optimal size of about 100 nm for efficient transport to and into the lymph node. The colloidal stability and binding of the antigen was stable for at least 4 months at storage- and in vivo-temperatures. The antigenicity of the RBD was maintained upon binding to the SiNP surface, and the receptor-binding motif was readily accessible due to the spatial orientation of the RBD. The particles were efficiently taken up in vitro by antigen-presenting cells. In a mouse immunization study using an mRNA vaccine and spike protein as benchmarks, we found that the SiNP formulation was able to elicit a stronger RBD-specific humoral response compared to the soluble protein. For the adjuvanted RBD-SiNP we found strong S-specific multifunctional CD4+ T cell responses, a balanced T helper response, improved auto- and heterologous virus neutralization capacity, and increased serum avidity, suggesting increased affinity maturation. In summary, our results provide further evidence for the possibility of optimizing the cellular and humoral immune response through antigen presentation on SiNP.

Long-term exposure to small-sized silica nanoparticles (SiO2-NPs) induces oxidative stress and impairs reproductive performance in adult zebrafish (Danio rerio)

The widespread use of silica nanoparticles (SiO2-NPs) in various industries, including chemical polishing, cosmetics, varnishes, medical, and food products, has increased the risk of their release into aquatic ecosystems. The toxic effects of small-size SiO2-NPs on the reproductive performance of zebrafish (Danio rerio) have yet to be widely studied. This study aimed to investigate the impact of chronic exposure to small-sized (35 ± 6 nm) SiO2-NPs on adult zebrafish through waterborne exposure to concentrations of 5 (SNP5), 10 (SNP10), 15 (SNP15), and 20 (SNP20) μg/L of SiO2-NPs for 28 days. Our results showed that SiO2-NPs significantly impacted several biochemical parameters, including cholesterol, triglycerides, LDL, HDL, total protein, albumin, urea levels, and alkaline phosphatase and aspartate aminotransferase activity. Cortisol and glucose levels in the SNP20 group significantly differed from the control group. All the exposed groups, apart from SNP5, experienced a significant increase in their total immunoglobulin levels and lysozyme activity. While there was a considerable increase in the activity of catalase and superoxide dismutase in all exposed groups, the expression of antioxidant genes did not appear to be affected. Furthermore, the expression level of il8 was significantly higher in SNP5 and SNP10 than in other treatments. Exposure to SiO2-NPs caused a decrease in gonad weight, absolute fecundity, and larval survival rate, particularly in the SNP20 group. The present study indicates that SiO2-NPs can harm zebrafish and thus further research is necessary to assess their health and environmental risks.

Adsorption of methyl orange dye by SiO2 mesoporous nanoparticles: adsorption kinetics and eco-toxicity assessment in Zea mays sprout and Artemia salina

Herein, we prepared the silica nanoparticles (SiO2 NPs) by a modified Stober's method for methyl orange (MO) removal. The SiO2 NPs were found to be spherical with a zeta size of 152.5 d. nm, a PDI of 0.377, and a zeta potential of -5.59 mV. The effect of different parameters (initial dye concentration, reaction time, temperature, and pH) on the adsorption of MO by SiO2 NPs was determined. The adsorption pattern of SiO2 NPs was highly fitted with the Langmuir, Freundlich, Redlich-Peteroen, and Temkin isotherm models. The highest adsorption rate was recorded at 69.40 mg/g of SiO2 NPs. Furthermore, the toxic effect of before and after removal of MO in aqueous solution was tested in terms of phytotoxicity and acute toxicity. The SiO2 NPs treated MO dye solution were not exhibited significant toxicity to corn seeds and Artemia salina. These results indicated that SiO2 NPs can be used for the adsorption of MO.

Use of Silica Nanoparticles for Drug Delivery in Cardiovascular Disease

PURPOSE

Cardiovascular disease (CVD) is the leading cause of death worldwide. The current CVD therapeutic drugs require long-term treatment with high doses, which increases the risk of adverse effects while offering only marginal treatment efficacy. Silica nanoparticles (SNPs) have been proven to be an efficient drug delivery vehicle for numerous diseases, including CVD. This article reviews recent progress and advancement in targeted delivery for drugs and diagnostic and theranostic agents using silica nanoparticles to achieve therapeutic efficacy and improved detection of CVD in clinical and preclinical settings.

METHODS

A search of PubMed, Scopus, and Google Scholar databases from 1990 to 2023 was conducted. Current clinical trials on silica nanoparticles were identified through ClinicalTrials.gov. Search terms include silica nanoparticles, cardiovascular diseases, drug delivery, and therapy.

FINDINGS

Silica nanoparticles exhibit biocompatibility in biological systems, and their shape, size, surface area, and surface functionalization can be customized for the safe transport and protection of drugs in blood circulation. These properties also enable effective drug uptake in specific tissues and controlled drug release after systemic, localized, or oral delivery. A range of silica nanoparticles have been used as nanocarrier for drug delivery to treat conditions such as atherosclerosis, hypertension, ischemia, thrombosis, and myocardial infarction.

IMPLICATIONS

The use of silica nanoparticles for drug delivery and their ongoing development has emerged as a promising strategy to improve the effectiveness of drugs, imaging agents, and theranostics with the potential to revolutionize the treatment of CVD.

Nanosilica and copper ecotoxicity in Gambusia holbrooki fish

When silica nanoparticles (SiNP) reach the water bodies interact with the already existing pollutants in the environments. This study aimed to evaluate the ecotoxicity of SiNP under the presence/absence of Cu in mosquitofish (Gambusia holbrooki). Fish were exposed to 0, 10 and 100 mg SiNP L-1, alone or mixed with Cu (0.25 mg L-1). After 96 h, the amount of colony forming units (CFU) of bacteria living on the skin mucus was analysed, and oxidative stress, tissue damage enzymes, and neurotoxicity were evaluated. We observed a reduction in CFU when Cu was present in the media. The liver was the target organ, evidencing a decrease in tissue damage enzymatic activities, activation of the antioxidant system in all treatments, and lipid oxidative damage when the SiNP and Cu were mixed. Overall, SiNP ecotoxicity was proved, which could also be enhanced by the presence of ubiquitous elements such as metals.

Nanocomposite orthopaedic bone cement combining long-acting dual antimicrobial drugs

Antibiotic loaded bone cements are widely used in total joint replacement (TJR); despite many limitations such as a burst release which leads to antibiotic concentration below inhibitory levels and possibly contributing to the selection of antibiotic resistant strains. In order to address such limitations and to simultaneously address antibiotic resistance and short-term antimicrobial activity, we developed a nanocomposite bone cement capable of providing a controlled release of antimicrobial agents from bone cement to act as prophylaxis or treatment against prosthetic joint infections (PJIs). Gentamicin and chlorhexidine were loaded in combination on silica nanoparticles surface using layer-by-layer coating technique (LbL) combining hydrolysable and non-hydrolysable polymers. The drug release from the nanocomposite continued for >50 days at concentrations higher than the commercial formulation containing the same amount of antimicrobial drugs, where burst release for few days were observed. Moreover, the nanocomposite bone cement showed superior antimicrobial inhibition without adversely affecting the mechanical properties or the ability of osteoblasts to grow. In vivo experiments with an infected bone lesion model along with mass-spectrometric analysis also provided further evidence of efficacy and safety of the implanted nanocomposite material as well as its prolonged drug eluting profile. The developed nanocomposite bone cement has the potential to reduce PJIs and enable treatment of resistant established infections; moreover, the newly developed LbL based nano-delivery system may also have wider applications in reducing the threat posed by antimicrobial resistance.

Effects of silica surface modification with silane and poly(ethylene glycol) on flexural strength, protein-repellent, and antibacterial properties of acrylic dental nanocomposites

OBJECTIVE

The main aim of the current work was to develop dental acrylic-based composites with protein-repellent and antibacterial properties by using surface-modified silica nanoparticles. The effects of surface modification of silica nanoparticles in protein-repellent and antibacterial activity and mechanical properties of dental composites including flexural strength, flexural modulus, and hardness were discussed.

METHODS

The surface of silica nanoparticles was first chemically treated with 3-methacryloxypropyltrimethoxysilane (MPS) as a coupling agent and then with poly(ethylene glycol) (PEG) bonded to MPS. Dental acrylic-based composites were prepared with mass fractions of 10, 15, 20, 30, and 40 % of PEG-modified MPS-silica nanoparticles (PMS). The chemical surface modification of silica nanoparticles with MPS and PEG was confirmed by Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA).

RESULTS

The dental composite containing 20 wt% PMS nanoparticles could reduce the protein adsorption by 28 % as compared with a composite containing 20 wt% MPS-modified silica. The antibacterial test indicated that the PMS nanoparticles can significantly reduce the adhesion of Streptococcus mutans and the biofilm formation on the surface of dental composites. It was found that the flexural strength increased by increasing the PMS nanoparticles from 0 to 20 wt% and then decreased by the incorporation of higher percentages of these nanoparticles. Also, with increasing the weight percentage of PMS nanoparticles, the elastic and the flexural modulus and the hardness of resin nanocomposites were increased.

SIGNIFICANCE

In the current work, for the first time, dental resin composites containing PEG were prepared with excellent protein-repellent and antibacterial properties.

Emergence of toxic trace elements in plant environment: Insights into potential of silica nanoparticles for mitigation of metal toxicity in plants

Emergence of trace elements at potentially toxic concentrations in the environment has become a global issue in recent times. Owing to the rapid population growth, unregulated industrialisation, intensive farming practices and excessive mining activities, these elements are accumulating in environment at high toxic concentrations. The exposure of plants to metal-contaminated environments severely influences their reproductive and vegetative growth, eventually affecting crop performance and production. Hence, it is crucial to find alternatives to mitigate the stress caused by toxic elements, in plants of agricultural importance. In this context, silicon (Si) has been widely recognized to alleviate metal toxicity and promote plant growth during various stress conditions. Amending soil with silicates has shown to ameliorate the lethal effects of metals and stimulates crop development. However, in comparison to silicon in bulk form, nano-sized silica particles (SiNPs) have been demonstrated to be more efficient in their beneficial roles. SiNPs can be used for various technological applications, viz. Improving soil fertility, agricultural yield, and remediating heavy metal-polluted soil. The research outcomes of studies focussing on role of silica nanoparticles to specifically mitigate the metal toxicity in plants have not been reviewed earlier in depth. The aim of this review is to explore the potential of SiNPs in alleviating metal stress and improving plant growth. The benefits of nano-silica over bulk-Si fertilizers in farming, their performance in diverse plant varieties, and the possible mechanisms to mitigate metal toxicity in plants have been discussed in detail. Further, research gaps are identified and future prospects are envisioned for advanced investigations in this field. The growing interest towards nano-silica related research will facilitate exploration of the true prospective of these nanoparticles for mitigation of metal stress in crops and in other fields of agriculture as well.

Bacteria metabolic adaptation to oxidative stress: the case of silica

Although the presence of silica in many living organisms offers advanced properties including cell protection, the different in vitro attempts to build living materials in pure silica never favoured the cells viability. Thus, little attention has been paid to host-guest interactions to modify the expected biologic response. Here we report the physiological changes undergone by Escherichia coli K-12 in silica from colloidal solution to gel confinement. We show that the physiological alterations in growing cultures are not triggered by the initial oxidative Reactive Oxygen Species (ROS) response. Silica promotes the induction of alternative metabolic pathways along with an increase of growth suggesting the existence of rpoS polymorphisms. Since the functionality of hybrid materials depends on the specific biologic responses of their guests, such cell physiological adaptation opens perspectives in the design of bioactive devices attracting for a large field of sciences.

Nanosilica size-dependent toxicity in Ceriodaphnia reticulata (Cladocera)

Silica nanoparticles (SiNP) are the most produced nanomaterials due to their variety of applications. When released to environments, surface water bodies are their main final sink. SiNP toxicity is still inconclusive and may vary according to particle properties such as their size. We analyzed the size-related effects of SiNP (22 and 244 nm) on mortality, life history traits, and oxidative stress in the cladoceran Ceriodaphnia reticulata. The smaller SiNP (LC5072 h: 105.5 µg/ml) were more lethal than the larger ones (LC5072 h >500 µg/ml). The 22 nm-sized SiNP decreased the number of molts and neonates, increased superoxide dismutase and inhibited glutathione S-transferase activities, while larger SiNP did not exert substantial effects on the organisms at the tested concentrations. In conclusion, SiNP toxicity depended on their size, and this information should be considered for regulatory purposes and to the development of safe-by-design nanoproducts to ultimately guarantee the environment protection.

Cellulose nanofibers decorated with SiO2 nanoparticles: Green adsorbents for removal of cationic and anionic dyes; kinetics, isotherms, and thermodynamic studies

Cellulose nanofibers decorated with SiO2 nanoparticles (SiO2-CNF) were prepared by the extraction of cellulose nanofibers from Yucca leaves, followed by modification with SiO2 nanoparticles, and used as efficient materials for the removal of both anionic and cationic dyes from the aqueous solution. Prepared nanostructures were characterized using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction powder (XRD), Thermogravimetric analysis (TGA), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), and transmission electron microscopy (TEM) analysis. The adsorption capacity of the nanostructures was investigated for the removal of both cationic (Methylene Blue, MB, and Crystal Violet, CV) and anionic (Eriochrome Black-T, EB) dyes. The kinetics of adsorption were investigated using some well-known models, including intraparticular diffusion (IPD), pseudo-first-order (PFO), pseudo-second-order (PSO), and Elovich. The adsorption isotherms were also explored using the Langmuir, Freundlich, Temkin, and Redlich-Peterson models. The obtained results revealed that the adsorption processes follow PSO kinetic and Langmuir isotherm models. Thermodynamic parameters of the adsorption were measured at different temperatures, indicating the feasibility and spontaneity of the adsorption. The pH and salt effects on adsorption were also explored. Finally, according to the reusability tests, the prepared adsorbents showed high recoverability without considerable loss in adsorption efficiency after five repeated runs.

Silica nanoparticles mediated insect pest management

Silicon is known for mitigating the biotic and abiotic stresses of crop plants. Many studies have proved beneficial effects of bulk silicon against biotic stresses in general and insect pests in particular. However, the beneficial effects of silica nanoparticles in crop plants against insect pests were barely studied and reported. By virtue of its physical and chemical nature, silica nanoparticles offer various advantages over bulk silicon sources for its applications in the field of insect pest management. Silica nanoparticles can act as insecticide for killing target insect pest or it can act as a carrier of insecticide molecule for its sustained release. Silica nanoparticles can improve plant resistance to insect pests and also aid in attracting natural enemies via enhanced volatile compounds emission. Silica nanoparticles are safe to use and eco-friendly in nature in comparison to synthetic pesticides. This review provides insights into the applications of silica nanoparticles in insect pest management along with discussion on its synthesis, side effects and future course of action.

Silica nanoparticles induce ovarian granulosa cell apoptosis via activation of the PERK-ATF4-CHOP-ERO1α pathway-mediated IP3R1-dependent calcium mobilization

Ambient particulate matters (PMs) have adverse effects in human and animal female reproductive health. Silica nanoparticles (SNPs), as a major component of PMs, can induce follicular atresia via the promotion of ovarian granulosa cell apoptosis. However, the molecular mechanisms of apoptosis induced by SNPs are not very clear. This work focuses on revealing the mechanisms of ER stress on SNP-induced apoptosis. Our results showed that spherical Stöber SNPs (110 nm, 25.0 mg/kg b.w.) induced follicular atresia via the promotion of granulosa cell apoptosis by intratracheal instillation in vivo; meanwhile, SNPs decreased the viability and increase apoptosis in granulosa cells in vitro. SNPs were taken up and accumulated in the vesicles of granulosa cells. Additionally, our results found that SNPs increased calcium ion (Ca2+) concentration in granulosa cell cytoplasm. Furthermore, SNPs activated ER stress via an increase in the PERK and ATF6 pathway-related protein levels and IP3R1-dependent calcium mobilization via an increase in IP3R1 level. In addition, 4-PBA restored IP3R1-dependent calcium mobilization and decreased apoptosis via the inhibition of ER stress. The ATF4-C/EBP homologous protein (CHOP)-ER oxidoreductase 1 alpha (ERO1α) pathway regulated SNP-induced IP3R1-dependent calcium mobilization and cell apoptosis via ATF4, CHOP, and ERO1α depletion in ovarian granulosa cells. Herein, we demonstrate that ER stress cooperated in SNP-induced ovarian toxicity via activation of IP3R1-mediated calcium mobilization, leading to apoptosis, in which the PERK-ATF4-CHOP-ERO1α pathway plays an essential role in ovarian granulosa cells.

Click derived organosilane assembled with nano platform for the detection of Cu2+ ions: Biological evaluation and molecular docking approach

Metal ions have active roles in biochemical, industrial, and environmental processes. The design and development of new rapid sensing materials with advanced reasonable, compelling, and convenient, techniques are urgent. Here in this work, we design and develop sensor with the facile amalgamation of the pyrene-based organosilane (5) through a click silylation approach silicon composite for selective detection of Cu²⁺ ions. Physicochemical and keen methods are employed to perceive the resultant hybrid nanoparticles (H-NPs), and these nanocomposites similarly displayed a strong affection for Cu²⁺ ions. In addition, the identification restrictions while utilizing 5 and H-NP's towards Cu²⁺ found in this study are far lower than the WHO rules for drinking water. Further, organosilane (5) shows good antibacterial and antioxidant activity. The antibacterial effects of triazole-based organosilane (5), are evaluated with a molecular docking study with Escherichia coli (IJZQ) was conducted. The selected ligand was revealed to have a reasonable docking score with a binding energy of -8.40 kcal mol^-1.

Cellulose acetate/silica composites: Physicochemical and biological characterization

Cellulose acetate is of remarkable scientific interest, becoming more useful when is used in obtaining of the composite materials containing nanoparticles, as result of its improved properties. Thus, cellulose acetate/silica composite films obtained by casting the solutions of cellulose acetate (CA)/tetraethyl orthosilicate (TEOS) in different mixing ratios were analyzed in this paper. The impact of TEOS addition, and implicitly of the silica nanoparticles on the mechanical strength, water vapor sorption properties and antimicrobial activity of the cellulose acetate/silica films were mainly monitored. The results of the tensile strength tests were discussed in correlation with data obtained from Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analysis. It was found that samples with low TEOS content show improved mechanical strength compared to samples with high amounts of TEOS. The microstructural characteristics of the studied films affect their moisture sorption capacity so that the weight of the adsorbed water increases with the addition of TEOS. These features are complemented with the antimicrobial activity against Staphylococcus aureus and Escherichia coli bacterial species. The obtained data show that the cellulose acetate/silica films, and especially those with low silica content have improved properties that can recommend them for applications in the biomedical field.

Dry liquid metals stabilized by silica particles: Synthesis and application in photothermoelectric power generation

HYPOTHESIS

Gallium-based room-temperature liquid metals (LMs) have unique physicochemical properties; however, their high surface tension, low flowability, and high corrosiveness to other materials limit their advanced processing (including precise shaping) and application. Consequently, LM-rich free-flowing powders, named "dry LMs" that offer the inherent advantages of dry powders, should play a critical role in expanding the application scope of LMs.

EXPERIMENTS

A general method of preparing silica-nanoparticle-stabilized LMs in the form of LM-rich powders (>95 wt% LM) is developed.

FINDINGS

Dry LMs can be simply prepared by mixing LMs with silica nanoparticles in a planetary centrifugal mixer in the absence of solvents. As a sustainable dry-process route alternative to wet-process routes, this ecofriendly and simple method of dry LM fabrication has several advantages, e.g., high throughput, scalability, and low toxicity owing to the lack of organic dispersion agents and milling media. Moreover, the unique photothermal properties of dry LMs are used for photothermal electric power generation. Thus, dry LMs not only pave the way for the use of LMs in powder form but also provide a new opportunity for expanding their application scope in energy conversion systems.

Diffusiophoresis of latex driven by anionic nanoparticles and their counterions

HYPOTHESIS

Diffusiophoresis of colloidal latex particles has been reported for molecular anions and cations of comparable size. In the present study, this phenomenon is observed for two types of charged colloids acting as multivalent electrolyte: (i) anionic charge-stabilised silica nanoparticles or (ii) minimally-charged sterically-stabilised diblock copolymer nanoparticles.

EXPERIMENTS

Using a Hele-Shaw cell, a thin layer of relatively large latex particles is established within a sharp concentration gradient of nanoparticles by sequential filling with water, latex particles and nanoparticles. Asymmetric diffusion is observed, which provides strong evidence for diffusiophoresis. Quantification involves turbidity measurements from backlit images.

FINDINGS

The latex particles diffuse across a concentration gradient of charged nanoparticles and the latex concentration front scales approximately with time^1/2. Moreover, the latex particle flux is inversely proportional to the concentration of background salt, confirming electrostatically-driven motion. These observations are consistent with theory recently developed to account for diffusiophoretic motion driven by multivalent ions.

Silica nanoparticles trigger phosphatidylserine exposure in red blood cells and induce thrombosis risk

Silica nanoparticles (SiNPs) have attracted increasing attention for their health effects due to the increased risk of exposure to human bodies via diverse routes. Considering that SiNPs enter the circulatory system and inevitably encounter red blood cells (RBCs), it is necessary to investigate their risk of causing erythrocytotoxicity. In this study, three sizes of SiNPs (SiNP-60, SiNP-120, and SiNP-200) were tested for their effects on mouse RBCs. The results showed that SiNPs could induce hemolysis, morphological changes, and phosphatidylserine (PS) exposure in RBCs in a particulate size-related manner. Further investigations on the underlying mechanism indicated that SiNP-60 exposure increased intracellular reactive oxidative species (ROS) generation and subsequently caused the phosphorylation of p38 and ERK1/2 in RBCs. The addition of antioxidants or inhibitors of mitogen-activated protein kinase (MAPK) signaling significantly attenuated PS exposure in RBCs and ameliorated SiNP-induced erythrocytotoxicity. Moreover, ex vivo assays using platelet-rich plasma (PRP) showed that SiNP-60-induced PS exposure in RBCs could trigger thrombin-dependent platelet activation. The contrary evidence from the assays of PS blockage and thrombin inhibition further confirmed that SiNP-60-induced platelet activation was dependent on PS externalization in RBCs, concomitantly with thrombin formation. These findings revealed the procoagulant and prothrombotic effects of SiNPs through the regulation of PS externalization in RBCs, and may be of great help in bridging the knowledge gap on the potential cardiovascular hazards of particulate silica from both artificial and naturally occurring origins.

MiR-5622-3p inhibits ZCWPW1 to induce apoptosis in silica-exposed mice and spermatocyte cells

Silica nanoparticles (SiNPs) could cause damage to spermatogenesis, and microRNAs were reported to be associated with male reproduction. This research was designed to explore the toxic impacts of SiNPs induced in male reproduction through miR-5622-3p. In vivo, 60 mice were randomized into the control group and SiNPs group, in which they were exposed to SiNPs for 35 days and then recovered for 15 days. In vitro, 4 groups were set: control group, SiNPs group, SiNPs + miR-5622-3p inhibitor group, and SiNPs + miR-5622-3p inhibitor negative control (NC) group. Our research indicated SiNPs caused the apoptosis of spermatogenic cells, increased level of γ-H2AX, raised the expressions of RAD51, DMC1, 53BP1, and LC8 which were DNA damage repair relative factors, and upregulated Cleaved-Caspase-9 and Cleaved-Caspase-3 levels. Furthermore, SiNPs also elevated the expression of miR-5622-3p but downregulated the level of ZCWPW1. However, miR-5622-3p inhibitor reduced the level of miR-5622-3p, increased the level of ZCWPW1, relieved DNA damage, and depressed the activation of apoptosis pathway, thus, alleviating spermatogenic cells apoptosis caused by SiNPs. The above-mentioned results indicated that SiNPs induced DNA damage resulting in activating of DNA damage response. Meanwhile, SiNPs raised the level of miR-5622-3p targeting inhibited expression of ZCWPW1 to suppress the repair process, possibly making DNA damage so severe that leading to the failure of DNA damage repair, finally inducing the apoptosis of spermatogenic cells.

Sugarcane ash and sugarcane ash-derived silica nanoparticles alter cellular metabolism in human proximal tubular kidney cells

Multiple epidemics of chronic kidney disease of an unknown etiology (CKDu) have emerged in agricultural communities around the world. Many factors have been posited as potential contributors, but a primary cause has yet to be identified and the disease is considered likely multifactorial. Sugarcane workers are largely impacted by disease leading to the hypothesis that exposure to sugarcane ash produced during the burning and harvest of sugarcane could contribute to CKDu. Estimated exposure levels of particles under 10 μm (PM₁₀) have been found to be exceptionally high during this process, exceeding 100  μg/m³ during sugarcane cutting and averaging ∼1800  μg/m³ during pre-harvest burns. Sugarcane stalks consist of ∼80% amorphous silica and generate nano-sized silica particles (∼200 nm) following burning. A human proximal convoluted tubule (PCT) cell line was subjected to treatments ranging in concentration from 0.025 μg/mL to 25 μg/mL of sugarcane ash, desilicated sugarcane ash, sugarcane ash-derived silica nanoparticles (SAD SiNPs) or manufactured pristine 200 nm silica nanoparticles. The combination of heat stress and sugarcane ash exposure on PCT cell responses was also assessed. Following 6-48 h of exposure, mitochondrial activity and viability were found to be significantly reduced when exposed to SAD SiNPs at concentrations 2.5 μg/mL or higher. Oxygen consumption rate (OCR) and pH changes suggested significant alteration to cellular metabolism across treatments as early as 6 h following exposure. SAD SiNPs were found to inhibit mitochondrial function, reduce ATP generation, increase reliance on glycolysis, and reduce glycolytic reserve. Metabolomic analysis revealed several cellular energetics pathways (e.g., fatty acid metabolism, glycolysis, and TCA cycle) are significantly altered across ash-based treatments. Heat stress did not influence these responses. Such changes indicate that exposure to sugarcane ash and its derivatives can promote mitochondrial dysfunction and disrupt metabolic activity of human PCT cells.

Investigation of Paracetamol Entrapped Nanoporous Silica Nanoparticles in Transdermal Drug Delivery System

An effort was made to administer paracetamol drug through transdermal patch, as no such formulation of this drug has been developed yet. The primary cause for the lack of such formulations is paracetamol's poor aqueous solubility. As a result, the current research concentrated on preparing nanomedicines, or drug-loaded nanoparticles, for delivery via transdermal formulations. Nanoparticles can improve the solubility of weakly aqueous soluble or even aqueous insoluble drugs by changing the crystalline structure of loaded medicines to an amorphous state and serving as drug permeation boosters. Silica nanoparticles (SNPs) were synthesized through sol-gel technique to achieve the aforementioned goal. DLS data revealed that the average particle size was around 100-200 nm, which was sufficient to penetrate the skin barrier. XRD analysis showed that the SNPs were amorphous, and the drug molecules lost their crystallinity after encapsulation into the nanoparticles, causing the enhancement of dissolution of drug molecules in physiological pH (pH-7.4). Different kinetic models were employed for the ex vivo dissolution data to evaluate the suitable kinetic model followed by the drug release in both burst and sustained phase. In vivo analgesic study was executed on mice applying each of the transdermal formulations to examine the performances of the patches.

Targeted Enzyme Activity Imaging with Quantitative Phase Microscopy

Quantitative phase imaging (QPI) is a powerful optical imaging modality for label-free, rapid, and three-dimensional (3D) monitoring of cells and tissues. However, molecular imaging of important intracellular biomolecules such as enzymes remains a largely unexplored area for QPI. Herein, we introduce a fundamentally new approach by designing QPI contrast agents that allow sensitive detection of intracellular biomolecules. We report a new class of bio-orthogonal QPI-nanoprobes for in situ high-contrast refractive index (RI) imaging of enzyme activity. The nanoprobes feature silica nanoparticles (SiO2 NPs) having higher RI than endogenous cellular components and surface-anchored cyanobenzothiazole-cysteine (CBT-Cys) conjugated enzyme-responsive peptide sequences. The nanoprobes specifically aggregated in cells with target enzyme activity, increasing intracellular RI and enabling precise visualization of intracellular enzyme activity. We envision that this general design of QPI-nanoprobes could open doors for spatial-temporal mapping of enzyme activity with direct implications for disease diagnosis and evaluating the therapeutic efficacy.

Silica nanoparticle-modified paper strip-based new rhodamine B chemosensor for highly selective detection of copper ions in drinking water

A new rhodamine B derivative (RDB) was synthesized and utilized for the colorimetric detection of copper ions (Cu²⁺). This chemosensor utilized a paper strip as a support and a smartphone as a detector for on-site quantitative detection of Cu²⁺ in water samples. Silica nanoparticles (SiNPs) were investigated as the modifier nanoparticles to achieve uniform color on the paper strip and showed a color response 1.9-fold higher than the one without SiNPs. The RDB chemosensor-based paper strip provided high selectivity toward Cu²⁺ with a detection limit of 0.7 mg/L, and the working concentrations for Cu²⁺ ranged from 1 to 17 mg/L. Parallel analyses of eight drinking water samples were conducted by inductively coupled plasma optical emission spectroscopy. The results were in good agreement, indicating the practical reliability of the established method with a short assay time and high selectivity. These indicate its great potential for on-site detection of Cu²⁺.