Effect of Shape on Mesoporous Silica Nanoparticles for Oral Delivery of Indomethacin

Evaluation of the synergistic effects of curcumin-resveratrol co-loaded biogenic silica on colorectal cancer cells

Colorectal cancer (CRC) remains a significant global health concern, being the third most diagnosed cancer in men and the second most diagnosed cancer in women, with alarming mortality rates. Natural phytochemicals have gained prominence among various therapeutic avenues explored due to their diverse biological properties. Curcumin, extracted from turmeric, and resveratrol, a polyphenol found in several plants, have exhibited remarkable anticancer activities. However, their limited solubility and bioavailability hinder their therapeutic efficacy. To enhance the bioavailability of these compounds, nanomaterials work as effective carriers with biogenic silica (BS) attracting major attention owing to their exceptional biocompatibility and high specific surface area. In this study, we developed Curcumin-resveratrol-loaded BS (Cur-Res-BS) and investigated their effects on colorectal cancer cell lines (HCT-116 and Caco-2). Our results demonstrated significant concentration-dependent inhibition of cell viability in HCT-116 cells and revealed a complex interplay of crucial proto-onco or tumor suppressor genes, such as TP53, Bax, Wnt-1, and CTNNB1, which are commonly dysregulated in colorectal cancer. Notably, Cur-Res-BS exhibited a synergistic impact on key signaling pathways related to colorectal carcinogenesis. While these findings are promising, further investigations are essential to comprehensively understand the mechanisms and optimize the therapeutic strategy. Moreover, rigorous safety assessments and in vitro studies mimicking the in vivo environment are imperative before advancing to in vivo experiments, ensuring the potential of Cur-Res-BS as an efficient treatment for CRC.

Tuning the Physical State of Aripiprazole by Mesoporous Silica

The main purpose of our studies is to demonstrate that commercially available mesoporous silica (MS) can be used to control the physical state of aripiprazole (ARP). The investigations performed utilizing differential scanning calorimetry and broadband dielectric spectroscopy reveal that silica can play different roles depending on its concentration in the system with amorphous ARP. At low MS content, it activates recrystallization of the active pharmaceutical ingredient and supports forming the III polymorphic form of ARP. At intermediate MS content (between ca. 27 and 65 wt %), MS works as a recrystallization inhibitor of ARP. At these concentrations, the formation of III polymorphic form is no longer favorable; therefore, it is possible to use this additive to obtain ARP in either IV or X polymorphic form. At the same time, employing MS in concentrations >65 wt % amorphous form of ARP with high physical stability can be obtained. Finally, regardless of the polymorphic form it crystallizes into, each composite is characterized by the same temperature dependence of relaxation times in the supercooled and glassy states.

Oral Delivery of Photopolymerizable Nanogels Loaded with Gemcitabine for Pancreatic Cancer Therapy: Formulation Design, and in vitro and in vivo Evaluations

Background

Gemcitabine (GEM) faces challenges of poor oral bioavailability and extensive first-pass metabolism. Currently, only injectable formulations are available for clinical use. Hence, there is an urgent demand for the development of advanced, efficacious, and user-friendly dosage forms to maintain its status as the primary treatment for pancreatic ductal adenocarcinoma (PDAC). Nanogels (NGs) offer a novel oral drug delivery system, ideal for hydrophilic compounds like GEM. This study aims to develop NGs tailored for GEM delivery, with the goal of enhancing cellular uptake and gastrointestinal permeability for improved administration in PDAC patients.

Methods

We developed cross-linked NGs via photopolymerization of methacryloyl for drug delivery of GEM. We reveal characterization, cytotoxicity, and cellular uptake studies in Caco-2 and MIA PaCa-2 cells. In addition, studies of in vitro permeability and pharmacokinetics were carried out to evaluate the bioavailability of the drug.

Results

Our results show NGs, formed via photopolymerization of methacryloyl, had a spherical shape with a size of 233.91±7.75 nm. Gemcitabine-loaded NGs (NGs-GEM) with 5% GelMA exhibited efficient drug loading (particle size: 244.07±19.52 nm). In vitro drug release from NGs-GEM was slower at pH 1.2 than pH 6.8. Cellular uptake studies indicated significantly enhanced uptake in both MIA PaCa-2 and Caco-2 cells. While there was no significant difference in GEM's AUC and Cmax between NGs-GEM and free-GEM groups, NGs-GEM showed markedly lower dFdU content (10.07 hr∙μg/mL) compared to oral free-GEM (19.04 hr∙μg/mL) after oral administration (p<0.01), highlighting NGs' efficacy in impeding rapid drug metabolism and enhancing retention.

Conclusion

In summary, NGs enhance cellular uptake, inhibit rapid metabolic degradation of GEM, and prolong retention after oral administration. These findings suggest NGs-GEM as a promising candidate for clinical use in oral pancreatic cancer therapy.

Characterization of Drug with Good Glass-Forming Ability Loaded Mesoporous Silica Nanoparticles and Its Impact Toward in vitro and in vivo Studies

Solid oral dosage forms are mostly preferred in pharmaceutical formulation development due to patient convenience, ease of product handling, high throughput, low manufacturing costs, with good physical and chemical stability. However, 70% of drug candidates have poor water solubility leading to compromised bioavailability. This phenomenon occurs because drug molecules are often absorbed after dissolving in gastrointestinal fluid. To address this limitation, delivery systems designed to improve the pharmacokinetics of drug molecules are needed to allow controlled release and target-specific delivery. Among various strategies, amorphous formulations show significantly high potential, particularly for molecules with solubility-limited dissolution rates. The ease of drug molecules to amorphized is known as their glass-forming ability (GFA). Specifically, drug molecules categorized into class III based on the Taylor classification have a low recrystallization tendency and high GFA after cooling, with substantial "glass stability" when heated. In the last decades, the application of mesoporous silica nanoparticles (MSNs) as drug delivery systems (DDS) has gained significant attention in various investigations and the pharmaceutical industry. This is attributed to the unique physicochemical properties of MSNs, including high loading capacity, recrystallization inhibition, excellent biocompatibility, and easy functionalization. Therefore, this study aimed to discuss the current state of good glass former drug loaded mesoporous silica and shows its impact on the pharmaceutical properties including dissolution and physical stability, along with in vivo study. The results show the importance of determining whether mesoporous structures are needed in amorphous formulations to improve the pharmaceutical properties of drug with a favorable GFA.

Functionalized nanohybrids with rod shape for improved chemo-phototherapeutic effect against cancer by sequentially generating singlet oxygen and carbon dioxide bubbles

The application of hybrid nanocarriers is expected to play an active role in improving treatment of chemotherapy and phototherapy. Herein, a nanohybrid with a core of mesoporous silica nanorods and shell of folate-functionalized zeolite imidazole framework (ZIF-8/FA) was synthesized via polydopamine (PDA)-mediated integration. A chemotherapeutic drug (DOX), bubble generator (NH4HCO3, ABC), and photosensitive agent (ICG) were simultaneously loaded into the delivery system to construct smart ZIF-8/FA-coated mesoporous silica nanorods (IDa-PRMSs@ZF). We found that ICG endowed the designed delivery system with a moderate photothermal conversion efficiency of 26.06% and the capacity to release 1O2. The produced hyperthermia caused ABC to decompose and further generate carbon dioxide bubbles, thereby facilitating DOX release, sequentially. Importantly, the underlying mechanism was also investigated using mathematical kinetic modeling. The tumor inhibition rate of IDa-PRMSs@ZF under NIR irradiation reached 83.8%. This study provides a promising strategy based on rod-shaped nanohybrids for effective combination antitumor therapy.

Exploiting recent trends for the synthesis and surface functionalization of mesoporous silica nanoparticles towards biomedical applications

Rapid progress in developing multifunctional nanocarriers for drug delivery has been observed in recent years. Inorganic mesoporous silica nanocarriers (MSNs), emerged as an ideal candidate for gene/drug delivery with distinctive morphological features. These ordered carriers of porous nature have gained unique attention due to their distinctive features. Moreover, transformation can be made to these nanocarriers in terms of pores size, pores volume, and particle size by altering specific parameters during synthesis. These ordered porous materials have earned special attention as a drug carrier for treating multiple diseases. Herein, we highlight the strategies employed in synthesizing and functionalizing these versatile nanocarriers. In addition, the various factors that influence their sizes and morphological features were also discussed. The article also summarizes the recent advancements and strategies for drug and gene delivery by rendering smarter MSNs by incorporating functional groups on their surfaces. Averting off-target effects through various capping strategies is a massive milestone for the induction of stimuli-responsive nanocarriers that brings out a great revolution in the biomedical field.

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MSNs serve as an ideal candidate for gene/drug delivery with unique and excellent attributes.

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MSNs surface can be functionalized using specific materials to impart unique structural features.

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Functionalization of MSNs with stimuli-responsive molecules can act as gatekeepers by responding to the desired stimulus after uncapping.

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These capping agents act as vital targeting agents in developing MSNs being employed in various biomedical applications.

Mesoporous Materials as Elements of Modern Drug Delivery Systems for Anti-Inflammatory Agents: A Review of Recent Achievements

Interest in the use of mesoporous materials as carriers of medicinal substances has been steadily increasing in the last two decades. Mesoporous carriers have application in the preparation of delivery systems for drugs from various therapeutic groups; however, their use as the carriers of anti-inflammatory agents is particularly marked. This review article, with about 170 references, summarizes the achievements in the application of mesoporous materials as the carriers of anti-inflammatory agents in recent years. This article will discuss a variety of mesoporous carriers as well as the characteristics of their porous structure that determine further use of these materials in the field of medical applications. Special attention will be paid to the progress observed in the construction of stimuli-responsive drug carriers and systems providing site-specific drug delivery. Subsequently, a review of the literature devoted to the use of mesoporous matrices as the carriers of anti-inflammatory drugs was carried out.

Biocompatible Supramolecular Mesoporous Silica Nanoparticles as the Next-Generation Drug Delivery System

Supramolecular mesoporous silica nanoparticles (MSNs) offer distinct properties as opposed to micron-sized silica particles in terms of their crystal structure, morphology–porosity, toxicity, biological effects, and others. MSN biocompatibility has touched the pharmaceutical realm to exploit its robust synthesis pathway for delivery of various therapeutic molecules including macromolecules and small-molecule drugs. This article provides a brief review of MSN history followed by special emphasis on the influencing factors affecting morphology–porosity characteristics. Its applications as the next-generation drug delivery system (NGDDS) particularly in a controlled release dosage form via an oral drug delivery system are also presented and shall be highlighted as oral delivery is the most convenient route of drug administration with the economical cost of development through to scale-up for clinical trials and market launch.

Pentapeptide modified ethosomes for enhanced skin retention and topical efficacy activity of indomethacin

Challenges associated with topical analgesics and anti-inflammatory drugs include poor drug penetration and retention at the desired lesion site. Therefore, improving these challenges would help to reduce the toxic and side effects caused by drug absorption into the systemic circulation and improve the therapeutic efficacy of topical therapeutic drugs. Pentapeptide (KTTKS) is a signal peptide in skin tissue, it can be recognized and bound by signal recognition particles. In the current study, we successfully prepared novel indomethacin (IMC) loaded KTTKS-modified ethosomes (IMC-KTTKS-Es), and the physicochemical properties and topical efficacy were investigated. Results showed that the prepared IMC-KTTKS-Es displayed a particle size of about 244 nm, a negative charge, good deformability, and encapsulation efficiency (EE) exceeding 80% for IMC, with a sustained release pattern. In vitro percutaneous permeation studies revealed that the skin retention was increased after the drug was loaded in the IMC-KTTKS-Es. Confocal laser scanning microscopy also showed improved skin retention of IMC-KTTKS-Es. In addition, IMC-KTTKS-Es showed improved topical analgesic and anti-inflammatory activity with no potentially hazardous skin irritation. This study suggested that the IMC-KTTKS-Es might be an effective drug carrier for topical skin therapy with a good safety profile.

Optimization of mirtazapine loaded into mesoporous silica nanostructures via Box-Behnken design: in-vitro characterization and in-vivo assessment

Employment of mesoporous silica nanostructures (MSNs) in the drug delivery field has shown a significant potential for improving the oral delivery of active pharmaceutical products with low solubility in water. Mirtazapine (MRT) is a tetracyclic antidepressant with poor water solubility (BCS Class II), which was recently approved as a potent drug used to treat severe depression. The principle of this research is to optimize the incorporation of Mirtazapine into MSNs to improve its aqueous solubility, loading efficiency, release performance, and subsequent bioavailability. The formulation was optimized by using of Box-Behnken Design, which allows simultaneous estimation of the impact of different types of silica (SBA-15, MCM-41, and Aluminate-MCM-41), a different drug to silica ratios (33.33%, 49.99%, and 66.66%), and different drug loading procedures (Incipient wetness, solvent evaporation, and solvent impregnation) on the MRT loading efficiency, aqueous solubility and dissolution rate. The optimized formula was achieved by loading MRT into SBA-15 at 33.33% drug ratio prepared by the incipient wetness method, which displayed a loading efficiency of 104.05%, water solubility of 0.2 mg/ml, and 100% dissolution rate after 30 min. The pharmacokinetic profile of the optimized formula was obtained by conducting the in-vivo study in rabbits which showed a marked improvement (2.14-fold) in oral bioavailability greater than plain MRT. The physicochemical parameters and morphology of the optimized formula were characterized by; gas adsorption manometry, scanning electron microscopy (SEM), polarized light microscopy (PLM), Fourier-transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), and X-ray powder diffraction (XRPD).

Structure-Property Relationship for Different Mesoporous Silica Nanoparticles and its Drug Delivery Applications: A Review

Mesoporous silica nanoparticles (MSNs) are widely used as a promising candidate for drug delivery applications due to silica’s favorable biocompatibility, thermal stability, and chemical properties. Silica’s unique mesoporous structure allows for effective drug loading and controlled release at the target site. In this review, we have discussed various methods of MSNs’ mechanism, properties, and its drug delivery applications. As a result, we came to the conclusion that more in vivo biocompatibility studies, toxicity studies, bio-distribution studies and clinical research are essential for MSN advancement.

Carboxyl-functionalized mesoporous silica nanoparticles for the controlled delivery of poorly water-soluble non-steroidal anti-inflammatory drugs

The purpose of this study was to investigate the delivery of poorly water-soluble non-steroidal anti-inflammatory drugs (NSAIDs) by carboxyl-functionalized mesoporous silica nanoparticles (MSN-COOH) with high specific surface area (S_BET). In this study, MSN-COOH was prepared by collaborative self-assembly using cetyltrimethylammonium bromide (CTAB) as template and hydrolysis (3-triethoxyl-propyl) succinic anhydride (TESPSA) as co-structure auxiliary directing agent (CSDA). The drug delivery systems were constructed with NSAIDs including Nimesulide (NMS) and Indomethacin (IMC) as model drugs. Moreover, the characterization techniques, hemolysis and bio-adsorption testes, in vitro drug release and in vivo biological studies of MSN-COOH were also carried out. The characterization results showed that MSN-COOH is spheres with clearly visible irregular honeycomb nanopores and rough surface (S_BET: 1257 m²/g, pore volume (V_P): 1.17 cm³/g). After loading NMS/IMC into MSN-COOH with high drug loading efficiency (NMS: 98.7 and IMC: 98.2%), most crystalline NMS and IMC converted to amorphous phase confirmed using differential scanning calorimeter (DSC) and X-ray power diffraction (XRD) analysis. Meanwhile, MSN-COOH significantly increased the dissolution of NMS and IMC compared with non-functionalized mesoporous silica nanoparticles (MSN), which was also confirmed by wettability experiments. The results of in vivo biological effects showed that MSN-COOH had higher bioavailability of NMS and IMC than MSN, and exerted strong anti-inflammatory effects by delivering more NMS and IMC in vivo. STATEMENT OF SIGNIFICANCE: This study successfully prepared MSNs-COOH (mesoporous silica nanoparticles modified with negatively charged carboxyl groups on the surface and in the pores) with high specific surface area and pore volume by using the negatively charged carboxyl group (hyd-TESPSA) and the positively charged CTAB self-assembled through electrostatic attraction under alkaline conditions. The drug delivery systems were constructed with Nimesulide (NMS) and Indomethacin (IMC) as model drugs. The results showed MSNs-COOH had high drug loading capacity and also exhibited good in vitro drug release properties. Interestingly, NMS loaded MSNs-COOH also had a potential pH responsive release effect. In vivo biological studies revealed that NMS/IMC loaded MSNs-COOH could evidently improve the bioavailability and played the strong anti-inflammatory effects.

Preparation of Magnetic-Luminescent Bifunctional Rapeseed Pod-Like Drug Delivery System for Sequential Release of Dual Drugs

Drug delivery systems (DDSs) limited to a single function or single-drug loading are struggling to meet the requirements of clinical medical applications. It is of great significance to fabricate DDSs with multiple functions such as magnetic targeting or fluorescent labeling, as well as with multiple-drug loading for enhancing drug efficacy and accelerating actions. In this study, inspired by the dual-chamber structure of rapeseed pods, biomimetic magnetic–luminescent bifunctional drug delivery carriers (DDCs) of 1.9 ± 0.3 μm diameter and 19.6 ± 4.4 μm length for dual drug release were fabricated via double-needle electrospraying. Morphological images showed that the rapeseed pod-like DDCs had a rod-like morphology and Janus dual-chamber structure. Magnetic nanoparticles and luminescent materials were elaborately designed to be dispersed in two different chambers to endow the DDCs with excellent magnetic and luminescent properties. Synchronously, the Janus structure of DDCs promoted the luminescent intensity by at least threefold compared to single-chamber DDCs. The results of the hemolysis experiment and cytotoxicity assay suggested the great blood and cell compatibilities of DDCs. Further inspired by the core–shell structure of rapeseeds containing oil wrapped in rapeseed pods, DDCs were fabricated to carry benzimidazole molecules and doxorubicin@chitosan nanoparticles in different chambers, realizing the sequential release of benzimidazole within 12 h and of doxorubicin from day 3 to day 18. These rapeseed pod-like DDSs with excellent magnetic and luminescent properties and sequential release of dual drugs have potential for biomedical applications such as targeted drug delivery, bioimaging, and sustained treatment of diseases.

Mesoporous Silica Particles as Drug Delivery Systems-The State of the Art in Loading Methods and the Recent Progress in Analytical Techniques for Monitoring These Processes

Conventional administration of drugs is limited by poor water solubility, low permeability, and mediocre targeting. Safe and effective delivery of drugs and therapeutic agents remains a challenge, especially for complex therapies, such as cancer treatment, pain management, heart failure medication, among several others. Thus, delivery systems designed to improve the pharmacokinetics of loaded molecules, and allowing controlled release and target specific delivery, have received considerable attention in recent years. The last two decades have seen a growing interest among scientists and the pharmaceutical industry in mesoporous silica nanoparticles (MSNs) as drug delivery systems (DDS). This interest is due to the unique physicochemical properties, including high loading capacity, excellent biocompatibility, and easy functionalization. In this review, we discuss the current state of the art related to the preparation of drug-loaded MSNs and their analysis, focusing on the newest advancements, and highlighting the advantages and disadvantages of different methods. Finally, we provide a concise outlook for the remaining challenges in the field.

Development of Thiabendazole-Loaded Mesoporous Silica Nanoparticles for Cancer Therapy

Thiabendazole (TBZ) is an anthelmintic drug currently studied for anticancer purposes. However, due to its low solubility, its biomedical application has been limited. Using mesoporous silica nanoparticles (MSNPs), such as Mobil Composition of Matter Number 41 (MCM-41), as a drug carrier, is a promising approach to improve the solubility of low water-soluble drugs. In the present work, we aim to develop TBZ-loaded MCM-41 (TBZ MCM-41) nanoparticles to improve the solubility and the therapeutic efficacy of TBZ against prostate cancer PC-3 cells. TBZ MCM-41 nanoparticles were synthesized with a size of 215.9 ± 0.07 nm, a spherical shape, a hexagonal array of channels, and a drug loading capacity of 19.1%. The biological effects of the nanoformulation on PC-3 cells were then evaluated using a 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT), IncuCyte live-cell imaging system, cell migration, and reactive oxygen species (ROS) assays. The results demonstrated that TBZ was released from MCM-41 nanoparticles in a controlled manner at pH values of 1.2 and 6.8. The cell viability measurements revealed that the TBZ MCM-41 nanoparticles caused a considerable 2.8-fold increase in the cytotoxicity of TBZ (IC₅₀ 127.3 and 46 μM for TBZ and TBZ MCM-41 nanoparticles, respectively). The results of the proliferation assay were in agreement with those of the cell viability measurements, where the MCM-41 increased the cytotoxicity of TBZ in a concentration-dependent manner. Also, the TBZ MCM-41 nanoparticles were found to enhance the potency of the drug and inhibit PC-3 cell migration. In addition, the ROS assay confirmed that TBZ MCM-41 nanoparticles were approximately 15% more potent than TBZ to produce ROS. Overall, the results demonstrated that MCM-41 nanoparticles are a promising carrier to improve the therapeutic efficacy of TBZ against PC-3 cells and suggest evaluating the efficacy of the formulation in vivo.

Insights into the ameliorating ability of mesoporous silica in modulating drug release in ternary amorphous solid dispersion prepared by hot melt extrusion

In this work, the application of various mesoporous silica grades in the preparation of stabilized ternary amorphous solid dispersions of Felodipine using hot melt extrusion was explored. We have demonstrated the effectiveness of mesoporous silica in these dispersions without the need for any organic solvents i.e., no pre-loading or immersion steps required. The physical and chemical properties, release profiles of the prepared formulations and the surface concentrations of the various molecular species were investigated in detail. Formulations containing 25 wt% and 50 wt% of Felodipine demonstrated enhanced stability and solubility of the drug substance compared to its crystalline counterpart. Based on the Higuchi model, ternary formulations exhibited a 2-step or 3-step release pattern which can be ascribed to the release of drug molecules from the organic polymer matrix and the external silica surface, followed by a release from the silica pore structure. According to the Korsmeyer-Peppas model, the release rate and release mechanism are governed by a complex quasi-Fickian release mechanism, in which multiple release mechanisms are occurring concurrently and consequently. Stability studies indicated that after 6 months storage of all formulation at 30% RH and 20 °C, Felodipine in all formulations remained stable in its amorphous state except for the formulation comprised of 40 wt% Syloid AL-1FP with a 50 wt% drug load.

Advances in regulating physicochemical properties of mesoporous silica nanocarriers to overcome biological barriers

Mesoporous silica nanoparticles (MSNs) with remarkable structural features have been proven to be an excellent platform for the delivery of therapeutic molecules. Biological barriers in various forms (e.g., mucosal barrier, cellular barrier, gastrointestinal barrier, blood-brain barrier, and blood-tumor barrier) present substantial obstacles for MSNs. The physicochemical parameters of MSNs are known to be effective and tunable not only for load and release of therapeutic molecules but also for their biological responsiveness that is beneficial for cells and tissues. This review innovatively provides a description of how and why physicochemical properties (e.g., particle size, morphology, surface charge, hydrophilic-hydrophobic property, and surface modification) of MSNs influence their ability to cross the biological barriers prior to reaching targeted sites. First, the structural and physiological features of biological barriers are outlined. Next, the recent progresses in the critical physicochemical parameters of MSNs are highlighted from physicochemical and biological aspects. Surface modification, as an important strategy for achieving rapid transport, is also reviewed with special attention to the latest findings of bioactive groups and molecular mechanisms. Furthermore, advanced designs of multifunction intelligent MSNs to surmount the blood-tumor barrier and to actively target tumor sites are demonstrated in detail. Lastly, the biodegradability and toxicity of MSNs are evaluated. With perspectives for their potential application and biosafety, the clues in summary might lead to drug delivery with high efficiency and provide useful knowledge for rational design of nanomaterials.

Chiral Mesoporous Silica Materials: A Review on Synthetic Strategies and Applications

Because of its tunable textural properties and chirality feature, chiral mesoporous silica (CMS) gained significant consideration in many fields and has been developed rapidly in recent years. In this review, we provide an overview of synthesis strategies for fabricating CMS together with its main applications. The properties of CMS, including morphology and mesostructures and enantiomer excess (ee), can be altered according to the synthetic conditions during the synthesis process. Despite its primary stage, CMS has attracted extensive attention in many fields. In particular, CMS nanoparticles are widely used for enantioselective resolution and adsorption of chiral compounds with desirable separation capability. Also, CMS acts as a promising candidate for the effective delivery of chiral or achiral drugs to produce a chiral-responsive manner. Moreover, CMS also plays an important role in chromatographic separations and asymmetric catalysis. There has been an in-depth review of the synthetic methods and mechanisms of CMS. And this review aims to give a deep insight into the synthesis and application of CMS, especially in recent years, and highlights the significance that it may have in the future.

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.

pH-Triggered Drug Release Controlled by Poly(Styrene Sulfonate) Growth Hollow Mesoporous Silica Nanoparticles

In the current report, hollow mesoporous silica (HMS) nanoparticles were successfully prepared by means of a hard-templating method and further modified with poly(styrene sulfonate) (PSS) via radical polymerization. Structural analysis, surface spectroscopy, and thermogravimetric characterization confirmed a successful surface modification of HMS nanoparticles. A hairy PSS was clearly visualized by high-resolution transmission electron microscopy measurement, and it is grown on the surface of HMS nanoparticles. The Brunauer-Emmett-Teller surface area and average pore size of HMS nanoparticles were reduced after surface modification because of the pore-blocking effect, which indicated that the PSS lies on the surface of nanoparticles. Nevertheless, the PSS acts as a "nano-gate" to control the release of curcumin which is triggered by pH. The drug-release profile of unmodified HMS nanoparticles showed a stormed release in both pH 7.4 and 5.0 of phosphate buffer saline buffer solution. However, a slow release (9.92% of cumulative release) of curcumin was observed at pH 7.4 when the surface of HMS nanoparticles was modified by PSS. The kinetic release study showed that the curcumin release mechanism from PSS@HMS nanoparticles followed the Ritger-Peppas kinetic model, which is the non-Fickian diffusion. Therefore, the PSS-decorated HMS nanoparticles demonstrate potential for pH-triggered drug release transport.

Superiority of L-tartaric Acid Modified Chiral Mesoporous Silica Nanoparticle as a Drug Carrier: Structure, Wettability, Degradation, Bio-Adhesion and Biocompatibility

PURPOSE

The purpose of this research was to study the basic physicochemical and biological properties regarding the application of L-tartaric acid modified chiral mesoporous silica nanoparticle (CMSN) as a drug carrier, and to explore the structure-property relationship of silica-based materials.

METHODS

CMSN with functions of carboxyl modification and chirality was successfully synthesized through co-condensation method, and the basic characteristics of CMSN, including morphology, structure, wettability, degradation, bio-adhesion and retention ability in gastrointestinal tract (GI tract) were estimated by comparing with non-functionalized mesoporous silica nanoparticles (MSN). Meanwhile, the biocompatibility and toxicity of L-tartaric modification were systematically evaluated both in vitro and in vivo through MTT cell viability assay, cell cycle and apoptosis assay, hemolysis assay, histopathology examination, hematology analysis, and clinical chemistry examination.

RESULTS

CMSN and MSN were spherical nanoparticles with uniform mesoporous structure. CMSN with smaller pore size and carboxyl functional groups exhibited better wettability. Besides, CMSN and MSN could dissolve thoroughly in simulated physiological fluids during a degradation period of 1-12 weeks. Interestingly, the in vitro and in vivo behaviors of carriers, including degradation, bio-adhesion and retention ability in the GI tract were closely related to wettability. As expected, CMSN had faster degradation rate, higher mucosa-adhesion ability, and longer retention time. Particularly, CMSN improved the bio-adhesion property in both gastric mucosa and small intestinal mucosa, and prolonged the GI tract retention time to at least 12 h, which meant higher probability for absorption. The biocompatibility and toxicity examination indicated that CMSN was a kind of biocompatible bio-material with good blood compatibility and negligible toxicity, which is required for further applications in biological fields.

CONCLUSION

CMSN with functions of carboxyl modification and chirality had superiority in terms of both physicochemical and biological properties. The in vitro and in vivo behaviors of carriers, including degradation, bio-adhesion, and retention were closely related to wettability.

Enlarged Pore Size Chiral Mesoporous Silica Nanoparticles Loaded Poorly Water-Soluble Drug Perform Superior Delivery Effect

Large mesopores of chiral silica nanoparticles applied as drug carrier are worth studying. In this study, chiral mesoporous silica nanoparticles (CMSN) and enlarged chiral mesoporous silica nanoparticles (E-CMSN) with a particle size from 200 to 300 nm were synthesized. Fourier transform infrared spectrometer (FTIR), circular dichroism spectrum, scanning electron microscopy (SEM), transmission electron microscope (TEM), and nitrogen adsorption/desorption measurement were adopted to explore their characteristics. The results showed that the surface area, pore volume, and pore diameter of E-CMSN were higher than those of CMSN due to enlarged mesopores. Poorly water-soluble drug nimesulide (NMS) was taken as the model drug and loaded into carriers using adsorption method. After NMS was loaded into CMSN and E-CMSN, most crystalline NMS converted to amorphous phase and E-CMSN was superior. The anti-inflammatory pharmacodynamics and in vivo pharmacokinetics results were consistent with the wetting property and in vitro drug dissolution results, verifying that NMS/E-CMSN exhibited superior NMS delivery system based on its higher oral relative bioavailability and anti-inflammatory effect because its enlarge mesopores contributed to load and release more amorphous NMS. The minor variations in the synthesis process contributed to optimize the chiral nano-silica drug delivery system.