Silica-based systems for oral delivery of drugs, macromolecules and cells

Silicon supplementation affects mineral metabolism but not bone density or strength in male broilers

Because leg injuries produce welfare concerns and impact production for broilers, numerous interventions have been suggested as potential solutions. One mineral which may affect bone quality is silicon. The objective of this study was to determine if supplementing bioavailable silicon could affect bone morphology, mineralization, and strength without negatively influencing welfare and meat quality. Male broilers were raised from d 1 after hatching until 42 d of age and randomly assigned to treatment groups for silicon supplementation in water: Control (no supplement, C; n = 125), Normal (0.011 ml supplement/kg bodyweight, N; n = 125) and High (0.063 ml supplement/kg bodyweight, H; n = 125). Toe damage, footpad dermatitis, hock burn, and keel blisters were assessed on d 42. Blood samples were collected from wing veins for serum osteocalcin, pyridinoline cross-links, and mineral analysis. Clinical QCT scans and analysis were conducted immediately before four-point bending tests of tibias. Texture analysis was performed on cooked fillets. Silicon supplementation tended to increase daily water consumption in N and H as compared to C (P = 0.07). Footpad dermatitis and hock burn scores were higher in H than in N or C (P < 0.05 for both comparisons). Supplementation altered serum minerals (P < 0.001), but bone density, morphology, and strength measures were similar among groups. The highest level of supplementation in the current study on a kg bodyweight basis was above recommended intakes but below previous amounts demonstrating silicon’s positive influence on bone, indicating that previously suggested minimum thresholds need to be reevaluated. Factors such as growth rate and mechanical loading likely play a greater role in developing bone quality than trying to supplement on top of good basic nutrition alone.

A Case Report Highlighting That Silica Gel Products Are Not Always Benign

INTRODUCTION

Silica gel packets are commonly used desiccants for medication products; these packets generally only pose a choking risk in young children. However, new cylindrical desiccant canisters have been developed, which may increase the risk for obstruction in adults.

CASE REPORT

An elderly male presented to the emergency department complaining of difficulty swallowing after taking his morning medications. Through a diligent work-up a desiccant canister was found lodged in the lower esophageal sphincter. The patient was endotracheally intubated and a Roth Net retriever was used to remove the canister.

CONCLUSION

Cylindrical desiccant canisters pose an increased risk of esophageal obstruction.

Comparative cytotoxic study of silica materials functionalised with essential oil components in HepG2 cells

This work evaluated the cytotoxic effect of different EOCs-functionalised silica particle types. The in vitro toxicity of eugenol and vanillin-immobilised SAS, MCM-41 microparticles and MCM-41 nanoparticles was evaluated on HepG2 cells, and compared to free EOCs and pristine materials. The results revealed that free essential oil components and bare silica had a mild cytotoxic effect on HepG2 cells. However, the comparative study showed that free eugenol and vanillin had a milder cytotoxic effect than the equivalent concentrations of immobilised components on the different silica particles, while differences in cell viability between the bare and functionalised particles relied on the type of analysed material. The most cytotoxic materials were eugenol and vanillin-functionalised MCM-41 micro with IC₅₀ values of 0.19 and 0.17 mg/mL, respectively, at 48 h exposure. Differences in cytotoxicity between functionalised particles may be attributed to the density of the functional components on their surface as a result of the functionalisation reaction performance for different materials. The study of the physico-chemical properties of particles demonstrated that cationic nature and increased hydrophobicity could be responsible for promoting cell-particle interactions for the eugenol and vanillin functionalised silica particles, enhancing their cytotoxic behaviour.

Degradation of silica particles functionalised with essential oil components under simulated physiological conditions

In this work, the biodurability of three silica particle types (synthetic amourphous silica, MCM-41 microparticles, MCM-41 nanoparticles) functionalised with three different essential oil components (carvacrol, eugenol, vanillin) was studied under conditions that represented the human gastrointestinal tract and lysosomal fluid. The effect of particle type, surface immobilised component and mass quantity on the physico-chemical properties of particles and silicon dissolution was determined. Exposure to biological fluids did not bring about changes in the zeta potential values or particle size distribution of the bare or functionalised materials, but the in vitro digestion process partially degraded the structure of the MCM-41 nanoparticles. Functionalisation preserved the structure of the MCM-41 nanoparticles after simulating an in vitro digestion process, and significantly decreased the amount of silicon dissolved after exposing different particles to both physiological conditions, independently of the essential oil component anchored to their surface. The MCM-41 microparticles showed the highest solubility, while synthetic amorphous silica presented the lowest levels of dissolved silicon. The study of these modified silica particles under physiological conditions could help to predict the toxicological behaviour of these new materials.

Mesoporous Silica Platforms with Potential Applications in Release and Adsorption of Active Agents

In recent years, researchers focused their attention on mesoporous silica nanoparticles (MSNs) owing to the considerable advancements of the characterization methods, especially electron microscopy methods, which allowed for a clear visualization of the pore structure and the materials encapsulated within the pores, along with the X-ray diffraction (small angles) methods and specific surface area determination by Brunauer–Emmett–Teller (BET) technique. Mesoporous silica gained important consideration in biomedical applications thanks to its tunable pore size, high surface area, surface functionalization possibility, chemical stability, and pore nature. Specifically, the nature of the pores allows for the encapsulation and release of anti-cancer drugs into tumor tissues, which makes MSN ideal candidates as drug delivery carriers in cancer treatment. Moreover, the inner and outer surfaces of the MSN provide a platform for further functionalization approaches that could enhance the adsorption of the drug within the silica network and the selective targeting and controlled release to the desired site. Additionally, stimuli-responsive mesoporous silica systems are being used as mediators in cancer therapy, and through the release of the therapeutic agents hosted inside the pores under the action of specific triggering factors, it can selectively deliver them into tumor tissues. Another important application of the mesoporous silica nanomaterials is related to its ability to extract different hazardous species from aqueous media, some of these agents being antibiotics, pesticides, or anti-tumor agents. The purpose of this paper is to analyze the methods of MSN synthesis and related characteristics, the available surface functionalization strategies, and the most important applications of MSN in adsorption as well as release studies. Owing to the increasing antibiotic resistance, the need for developing materials for antibiotic removal from wastewaters is important and mesoporous materials already proved remarkable performances in environmental applications, including removal or even degradation of hazardous agents such as antibiotics and pesticides.

Hesperidin: synthesis and characterization of bioflavonoid complex

Flavonoids are widely recognized for their beneficial effects in the cosmetic industry, possessing many biological activities, such as antioxidant, anti-inflammatory and antimicrobial properties. The study presented an efficient and simple solution to improve the preparations of antioxidant complexes based on hesperidin. Obtained products are characterized by thermogravimetric, spectrophotometric method, electron scanning microscopy, color analysis and zeta potential. Lightness value (L*) of hesperidin-silica complexes was found to be inversely correlated with the antioxidant activity values.

Activation of MAPK and Cyclin D1/CDK4 in Malignant Transformation of Human Embryonic Lung Fibroblasts Induced by Silica and Benzopyrene

Objective:

Silica and Benzo(a)pyrene are listed as carcinogens. This study aims to explore Cyclin D1, CDK4 and difference of cell cycle adjusted by MAPK signal transduction pathway in silica and B(a)P-induced malignant transformation of human embryonic lung fibroblasts.

Methods:

Activity of the subfamily (ERK, p38 and JNK) of mitogen-activated protein kinase (MAPK), cyclin D1 and CDK4 (cyclin dependent kinase) were evaluated using Human embryonic lung fibroblast (HELF) purchased from the cell room, basic research institute, Chinese Academy of Medical Sciences. The expression of cyclin D1 and CDK4 (cyclin dependent kinase) were measured in silica and B(a)P induced malignant using Western blot (WB) assay.

Results:

P-ERK and P-JNK expression increased significantly (P<0.01), while CDK4 and P-p38 expression decreased (P<0.01, P<0.05) in silica-induced malignant transformation cells compared with the control group. P-ERK, P-JNK and Cyclin D1 expression increased (P<0.01, P<0.01, P<0.05) in B(a)P-induced group compared with the control group. P-ERK and P-JNK expression decreased (P<0.01), while P-p38, Cyclin D1 and CDK4 expression increased (P<0.05, P<0.05, P<0.01) in B(a)P-induced group compared with the silica-induced group.

Conclusion:

MAPK and cyclin D1/CDK4 activation expressed differently in human embryo lung fibroblasts malignant transformation induced by silica and benzopyrene.

Effects of miR-26a on Osteogenic Differentiation of Bone Marrow Mesenchymal Stem Cells by a Mesoporous Silica Nanoparticle - PEI - Peptide System

INTRODUCTION

RNA-based therapy for bone repair and regeneration is a highly safe and effective approach, which has been extensively investigated in recent years. However, the molecular stability of RNA agents still remains insufficient for clinical application. High porosity, tunable size, and ideal biodegradability and biosafety are a few of the characters of mesoporous silicon nanoparticles (MSNs) that render them a promising biomaterial carrier for RNA treatment.

MATERIALS AND METHODS

In this study, a novel miR-26a delivery system was constructed based on MSNs. Next, we assessed the miRNA protection of the delivery vehicles. Then, rat bone marrow mesenchymal stem cells (rBMSCs) were incubated with the vectors, and the transfection efficiency, cellular uptake, and effects on cell viability and osteogenic differentiation were evaluated.

RESULTS

The results demonstrated that the vectors protected miR-26a from degradation in vitro and delivered it into the cytoplasm. A relatively low concentration of the delivery systems significantly increased osteogenic differentiation of rBMSCs.

CONCLUSION

The vectors constructed in our study provide new methods and strategies for the delivery of microRNAs in bone tissue engineering.

Synthesis of sol-gel derived calcium silicate particles and development of a bioactive endodontic cement

OBJECTIVE

The aim of this study is to produce sol-gel derived calcium silicate particles (CS) and evaluate the influence of different concentration of calcium tungstate in the physical, chemical, mechanical and biological properties of developed cements.

METHODS

Sol-gel route were used to synthesize calcium silicate particles that were characterized with x-ray difraction, Fourier transformed infrared spectroscopy, scanning electron microscopy, laser diffraction and nitrogen absorption. Cements were formulated with the addition of different concentrations of calcium tungstate (CaWO₄), resulting in four experimental groups according to the CS:CaWO₄ ratio: CS₁₀₀ (100:0), CS₉₀ (90:10), CS₈₀ (80:20), CS₇₀ (70:30). The setting time, radiopacity, compressive strength, pH, calcium release, cell proliferation and cell differentiation were used to characterize the cements.

RESULTS

CS particles were succesfully sinthesized. The addition of CaWO₄ increased the radiopacity and did not influenced the setting time and the mechanical properties of cements. The pH of distilled water was increased for all groups and the CS₁₀₀ and CS₉₀ groups presented incresed calcium release. Reduced cell viability was found for CS₇₀ while CS₁₀₀ and CS₉₀ presented higher ALP activity and % of mineralized nodules after 21 days.

SIGNIFICANCE

Sol-gel derived CS particles were sucssfully developed with potential to applied for the production of bioactive ceramic cements. The addition of 10% of CaWO₄ resulted in cements with adequate properties and bioactivity being an alternative for regenerative endodontic treatments.

Drug-templated mesoporous silica nanocontainers with extra high payload and controlled release rate

The possibility of one-step creating of pH-sensitive mesostructured silica-based nanocontainers with exceptionally high payload using associates of two antiseptics (including hydrolyzable one) as templates is demonstrated. The effects of the template nature and the conditions of the sol-gel process on the porous structure of silica nanocontainers are studied and discussed. The kinetics of the templating drug release from such containers is studied and some features of this process are analyzed. It is shown that the drug release rate can be tuned by varying the medium pH. The bactericidal activity of two encapsulated antiseptics against the Staphylococcus aureus is evaluated in vitro by agar diffusion method with replacement of agar with agarose. The diameters of the inhibition zones for silica-based containers loaded with antiseptics increased with the pre-diffusion time at 4 °C. At the same time, empty containers (after elimination of antiseptics by etching) did not reveal any bactericidal properties.

Natural Diatom Biosilica as Microshuttles in Drug Delivery Systems

Unicellular diatom microalgae are a promising natural resource of porous biosilica. These microorganisms produce around their membrane a highly porous and extremely structured silica shell called frustule. Once harvested from living algae or from fossil sediments of diatomaceous earth, this biocompatible and non-toxic material offers an exceptional potential in the field of micro/nano-devices, drug delivery, theranostics, and other medical applications. The present review focused on the use of diatoms in the field of drug delivery systems, with the aim of presenting the different strategies implemented to improve the biophysical properties of this biosilica in terms of drug loading and release efficiency, targeted delivery, or site-specific binding capacity by surface functionalization. The development of composite materials involving diatoms for drug delivery applications is also described.

Nanoparticles Targeting Macrophages as Potential Clinical Therapeutic Agents Against Cancer and Inflammation

With the development of nanotechnology, significant progress has been made in the design, and manufacture of nanoparticles (NPs) for use in clinical treatments. Recent increases in our understanding of the central role of macrophages in the context of inflammation and cancer have reinvigorated interest in macrophages as drug targets. Macrophages play an integral role in maintaining the steady state of the immune system and are involved in cancer and inflammation processes. Thus, NPs tailored to accurately target macrophages have the potential to transform disease treatment. Herein, we first present a brief background information of NPs as drug carriers, including but not limited to the types of nanomaterials, their biological properties and their advantages in clinical application. Then, macrophage effector mechanisms and recent NPs-based strategies aimed at targeting macrophages by eliminating or re-educating macrophages in inflammation and cancer are summarized. Additionally, the development of nanocarriers targeting macrophages for disease diagnosis is also discussed. Finally, the significance of macrophage-targeting nanomedicine is highlighted, with the goal of facilitating future clinical translation.

USE OF SORPTION PROCESSES IN THE TECHNOLOGY OF DRUG DELIVERY SYSTEMS

The aimof this research is the review of scientific and technical literature regarding possibility of using sorption processes in the technology of drug delivery systems.

Materials and methods. The materials are the following electronic resources: eLIBRARY, CyberLeninka, PubMed. The methods of review are analysis and synthesis. The study covers the scientific literature from 1996 up to the present time.

Results.Sorbents are used as carriers for various medicinal peroral substances, they are also dispensers of various compounds in the form of polymeric eye films and stents in the human body. The delivery of medicinal substances occurs with the help of sorption processes of mass transfer. Currently, the following medical substances are used as carriers for medicinal substances: activated carbon, mineral sorbents (medical clays, synthetic sorbents), polymers and their biosimilars. 6 groups of pharmaceutical substances are registered for the production of enterosorbents in Russia and they can be used as sorbent carriers in the sorption drug system. They are: activated carbon, colloidal silicon dioxide, polyvinylpyrrolidone, dioctahedral smectite, polymethylsiloxane polyhydrate. As a result of the study, the model of the sorption drug system has been developed. It consists of sorbent carrier, active pharmaceutical ingredient and excipients that provide the desorption. Desorption of the active pharmaceutical ingredient may contribute to its modified release. The technology for obtaining sorption medicinal systems requires further study and development of modeling methods, searching for experimental pharmacological models and technological methods, which make it possible to obtain sorption dosage form with modified release.

Conclusion.The review of the sorption processes used in the technology of drug delivery systems has been carried out. The model of the sorption drug system has been developed.

Effect of Calcium Precursor on the Bioactivity and Biocompatibility of Sol-Gel-Derived Glasses

This study investigated the impact of different calcium reagents on the morphology, composition, bioactivity and biocompatibility of two-component (CaO-SiO₂) glasses produced by the Stöber process with respect to their potential application in guided tissue regeneration (GTR) membranes for periodontal repair. The properties of the binary glasses were compared with those of pure silica Stöber particles. The direct addition of calcium chloride (CC), calcium nitrate (CN), calcium methoxide (CM) or calcium ethoxide (CE) at 5 mol % with respect to tetraethyl orthosilicate in the reagent mixture gave rise to textured, micron-sized aggregates rather than monodispersed ~500 nm spheres obtained from the pure silica Stöber synthesis. The broadening of the Si-O-Si band at ~1100 cm-1 in the infrared spectra of the calcium-doped glasses indicated that the silicate network was depolymerised by the incorporation of Ca2+ ions and energy dispersive X-ray analysis revealed that, in all cases, the Ca:Si ratios were significantly lower than the nominal value of 0.05. The distribution of Ca2+ ions was also found to be highly inhomogeneous in the methoxide-derived glass. All samples released soluble silica species on exposure to simulated body fluid, although only calcium-doped glasses exhibited in vitro bioactivity via the formation of hydroxyapatite. The biocompatibilities of model chitosan-glass GTR membranes were assessed using human MG63 osteosarcoma cells and were found to be of the order: CN < pure silica ≈ CC << CM ≈ CE. Calcium nitrate is the most commonly reported precursor for the sol-gel synthesis of bioactive glasses; however, the incomplete removal of nitrate ions during washing compromised the cytocompatibility of the resulting glass. The superior bioactivity and biocompatibility of the alkoxide-derived glasses is attributed to their ease of dissolution and lack of residual toxic anions. Overall, calcium ethoxide was found to be the preferred precursor with respect to extent of calcium-incorporation, homogeneity, bioactivity and biocompatibility.

Bimodal antibacterial system based on quaternary ammonium silane-coupled core-shell hollow mesoporous silica

Hollow mesoporous silica (HMS) have been extensively investigated as a biomaterial for drug delivery. The present study developed quaternary ammonium silane-grafted hollow mesoporous silica (QHMS) to create a metronidazole (MDZ) sustained delivery system, MDZ@QHMS, with bimodal, contact-kill and release-kill capability. The QHMS was assembled through a self-templating method. Metronidazole was incorporated within the QHMS core using solvent evaporation. Antibacterial activities of the MDZ@QHMS were investigated using single-species biofilms of Staphylococcus aureus (ATCC25923), Escherichia coli (ATCC25922) and Porphyromonas gingivalis (ATCC33277). The MDZ@QHMS maintained a hollow mesoporous structure and demonstrated sustained drug release and bacteridal actvity against the three bacterial strains at a concentration of 100 μg/mL or above. These nanoparticles were not relatively cytotoxic to human gingival fibroblasts when employed below 100 µg/mL. Compared with HMS, the MDZ@QHMS system at the same concentration demonstrated antibiotic-elution and contact-killing bimodal antibacterial activities. The synthesized drug carrier with sustained, bimodal antibacterial function and minimal cytotoxicity possesses potential for localized antibiotic applications. STATEMENT OF SIGNIFICANCE: The present study develops quaternary ammonium silane-grafted hollow mesoporous silica (QHMS) to create a metronidazole (MDZ) sustained delivery system, MDZ@QHMS, with bimodal, contact-kill and release-kill capability. This system demonstrates sustained drug release and maintained a hollow mesoporous structure. The synthesized drug carrier with sustained, bimodal antibacterial function and excellent biocompatibility possesses potential for localized antibiotic applications.

Enhancing oral bioavailability of poorly soluble drugs with mesoporous silica based systems: opportunities and challenges

Porous silica-based drug delivery systems have shown considerable promise for improving the oral delivery of poorly water-soluble drugs. More specifically, micro- and meso-porous silica carriers have high surface areas with associated ability to physically adsorb high-drug loads in a molecular or amorphous form; this allows molecular state drug release in aqueous gastrointestinal environments, potential for supersaturation, and hence facilitates enhanced absorption and increased bioavailability. This review focuses primarily on the ability of porous silica materials to modulate in vitro drug release and enhance in vivo biopharmaceutical performance. The key considerations identified and addressed are the physicochemical properties of the porous silica materials (e.g. the particle and pore size, shape, and surface chemistry), drug specific properties (e.g. pKa, solubility, and nature of interactions with the silica carrier), potential for both immediate and controlled release, drug release mechanisms, potential for surface functionalization and inclusion of precipitation inhibitors, and importance of utilizing relevant and effective in vitro dissolution methods with discriminating dissolution media that provides guidance for in vivo outcomes (i.e. IVIVC).

Diatoms Green Nanotechnology for Biosilica-Based Drug Delivery Systems

Diatom microalgae are the most outstanding natural source of porous silica. The diatom cell is enclosed in a three-dimensional (3-D) ordered nanopatterned silica cell wall, called frustule. The unique properties of the diatom frustule, including high specific surface area, thermal stability, biocompatibility, and tailorable surface chemistry, make diatoms really promising for biomedical applications. Moreover, they are easy to cultivate in an artificial environment and there is a large availability of diatom frustules as fossil material (diatomite) in several areas of the world. For all these reasons, diatoms are an intriguing alternative to synthetic materials for the development of low-cost drug delivery systems. This review article focuses on the possible use of diatom-derived silica as drug carrier systems. The functionalization strategies of diatom micro/nanoparticles for improving their biophysical properties, such as cellular internalization and drug loading/release kinetics, are described. In addition, the realization of hybrid diatom-based devices with advanced properties for theranostics and targeted or augmented drug delivery applications is also discussed.

Water Interactions with Hydrophobic versus Hydrophilic Nanosilica

It is well-known that interaction of hydrophobic powders with water is weak, and upon mixing, they typically form separated phases. Preparation of hydrophobic nanosilica AM1 with a relatively large content of bound water with no formation of separated phases was the aim of this study. Unmodified nanosilica A-300 and initial AM1 (A-300 completely hydrophobized by dimethyldichlorosilane), compacted A-300 (cA-300), and compacted AM1 (cAM1) containing 50-58 wt % of bound water were studied using low-temperature ¹H NMR spectroscopy, thermogravimetry, infrared spectroscopy, microscopy, small-angle X-ray scattering, nitrogen adsorption, and theoretical modeling. After mechanical activation (∼20 atm) upon stirring of AM1/water mixture at the degree of hydration h = 1.0 or 1.4 g of distilled water per gram of dry silica, all water is bound and the blend has the bulk density of 0.7 g/cm³. The temperature and interfacial behaviors of bound water depend strongly on a dispersion media type (air, chloroform, and chloroform with trifluoroacetic acid (4:1)) because the boundary area between immiscible water and chloroform should be minimal. Water and chloroform molecules are of different sizes affecting their distribution in pores (voids between silica nanoparticles in their aggregates) of different sizes. Structural, morphological, and textural characteristics of silicas, and environmental features affect not only the distribution of bound water, but also the amounts of strongly (frozen at T < 260 K) and weakly (frozen at 260 K < T < 273 K) bound and strongly (chemical shift δ_H = 4-6 ppm) and weakly (δ_H = 1-2 ppm) associated waters. Despite the changes in the characteristics of cAM1, it demonstrates a flotation effect. The developed system with cAM1/bound water could be of interest from a practical point of view due to controlled interactions with aqueous surroundings.

Sol-gel Silica Nanoparticles in Medicine: A Natural Choice. Design, Synthesis and Products

Silica is one of the most abundant minerals in the Earth's crust, and over time it has been introduced first into human life and later into engineering. Silica is present in the food chain and in the human body. As a biomaterial, silica is widely used in dentistry, orthopedics, and dermatology. Recently amorphous sol-gel SiO₂ nanoparticles (NPs) have appeared as nanocarriers in a wide range of medical applications, namely in drug/gene target delivery and imaging diagnosis, where they stand out for their high biocompatibility, hydrophilicity, enormous flexibility for surface modification with a high payload capacity, and prolonged blood circulation time. The sol-gel process is an extremely versatile bottom-up methodology used in the synthesis of silica NPs, offering a great variety of chemical possibilities, such as high homogeneity and purity, along with full scale pH processing. By introducing organic functional groups or surfactants during the sol-gel process, ORMOSIL NPs or mesoporous NPs are produced. Colloidal route, biomimetic synthesis, solution route and template synthesis (the main sol-gel methods to produce monosized silica nanoparticles) are compared and discussed. This short review goes over some of the emerging approaches in the field of non-porous sol-gel silica NPs aiming at medical applications, centered on the syntheses processes used.

Mesoporous silica nanoparticles induced hepatotoxicity via NLRP3 inflammasome activation and caspase-1-dependent pyroptosis

Increased biomedical applications of mesoporous silica nanoparticles (MSNs) raise considerable attention concerning their toxicological effects; the toxicities of MSNs are still undefined and the underlying mechanisms are unknown. We conducted this study to determine the hepatotoxicity of continuous administration of MSNs and the potential mechanisms. MSNs caused cytotoxicity in hepatic L02 cells in a dose- and time-dependent manner. Then, MSNs were shown to elicit NOD-like receptor protein 3 (NLRP3) inflammasome activation in hepatocytes, leading to caspase-1-dependent pyroptosis, a novel manner of cell death. In vivo MSN administration triggered hepatotoxicity as indicated by increased histological injury, serum alanine aminotransferase and serum aspartate aminotransferase. Notably, NLRP3 inflammasome and pyroptosis were also activated during the treatment. Meanwhile, in NLRP3 knockout mice and caspase-1 knockout mice, MSN-induced liver inflammation and hepatotoxicity could be abolished. Furthermore, experiments indicated that MSNs induced mitochondrial reactive oxygen species (ROS) generation, and the ROS scavenger could attenuate the MSN-activated NLRP3 inflammasomes and pyroptosis in the liver. Collectively, these data suggested that MSNs triggered liver inflammation and hepatocyte pyroptosis through NLRP3 inflammasome activation, which was caused by MSN-induced ROS generation. Our study provided novel insights into the hepatotoxicity of MSNs and the underlying mechanisms, and facilitated the potential approach to increase the biosafety of MSNs.

Synthesis of Controlled-Size Silica Nanoparticles from Sodium Metasilicate and the Effect of the Addition of PEG in the Size Distribution

Silica nanoparticles are widely studied in emerging areas of nanomedicine because they are biocompatible, and their surface can be modified to provide functionalization. The size is intrinsically related to the performance of the silica nanoparticles; therefore, it is important to have control over the size. However, the silica nanoparticles obtained from sodium metasilicate are less studied than those obtained from tetraethyl orthosilicate. Moreover, the methods of surface modification involve several steps after the synthesis. In this work, the effect of different concentrations of sodium metasilicate on the size of silica nanoparticles was studied. In the same way, we studied the synthesis of organically modified silica nanoparticles in a one-step method, using poly(ethylene glycol). The nanoparticles were characterized by scanning electron microscopy, Fourier-transform infrared spectroscopy, and thermogravimetric analysis. It was found that the size distribution of the silica nanoparticles could be modified by changing the initial concentration of sodium metasilicate. The one-step surface-modification method caused a significant decrease in size distribution.

Lipid-coated mesoporous silica microparticles for the controlled delivery of β-galactosidase into intestines

Coating of mesoporous silica carriers with dioleoylphosphatidylcholine allowed triggering of the selective delivery of functional enzymes by lipolysis under simulated intestinal conditions.

Innovative strategies for intervertebral disc regenerative medicine: From cell therapies to multiscale delivery systems

As our understanding of the physiopathology of intervertebral disc (IVD) degeneration has improved, novel therapeutic strategies have emerged, based on the local injection of cells, bioactive molecules, and nucleic acids. However, with regard to the harsh environment constituted by degenerated IVDs, protecting biologics from in situ degradation while allowing their long-term delivery is a major challenge. Yet, the design of the optimal approach for IVD regeneration is still under debate and only a few papers provide a critical assessment of IVD-specific carriers for local and sustained delivery of biologics. In this review, we highlight the IVD-relevant polymers as well as their design as macro-, micro-, and nano-sized particles to promote endogenous repair. Finally, we illustrate how multiscale systems, combining in situ-forming hydrogels with ready-to-use particles, might drive IVD regenerative medicine strategies toward innovation.

Evaluation of mesoporous silica nanoparticles for oral drug delivery - current status and perspective of MSNs drug carriers

The oral pathway is considered as the most common method for drug administration, although many drugs, especially the highly pH- and/or enzymatic biodegradable peptide drugs, are very difficult to formulate and achieve a good intestinal absorption. Efficient systematic absorption of an active substance, delivered via oral ingestion, is only achievable if the drug (1) is substantially present as a solution in the gastrointestinal tract, (2) is able to penetrate through the intestinal mucus, (3) overcomes the different gastrointestinal barriers, and (4) provides an effective therapeutic dose. Therefore, optimization of oral bioavailability of poorly-soluble drugs still remains a significant challenge for the pharmaceutical industry. Even though numerous conventional drug carriers have successfully solved some of the issues related to oral delivery of poorly-soluble drugs, only few of them met commercialization requirements. These drawbacks have led the scientific world to reconsider its approaches toward targeted drug delivery systems and researchers started looking for alternative vectorized carriers. In this area, nanoparticle-based materials have several significant advantages over free and non-formulated drugs. For example, nanosized porous silica carriers allow for more sustained and controlled drug release or improved oral bioavailability. Thus, in the present review, we will highlight the most important features of nanostructured silica drug carriers, such as particle size, particle shape, surface roughness or surface functionalization, and underline the key advantages of these nanosupports. In particular, this article will discuss recent progress and challenges in the area of mesoporous silica nanocarriers used for oral drug delivery. Additional emphasis will be set on the biological and chemical features of the gastrointestinal tract as well as currently tested nanoformulations and strategies to avoid drug degradation in the gastrointestinal environment.