Biofunctionalized phospholipid-capped mesoporous silica nanoshuttles for targeted drug delivery: improved water suspensibility and decreased nonspecific protein binding

Engineered mesoporous silica nanoparticles, new insight nanoplatforms into effective cancer gene therapy

The use of nucleic acid to control the expression of genes relevant to tumor progression is a key therapeutic approach in cancer research. Therapeutics based on nucleic acid provide novel concepts for untreatable targets. Nucleic acids as molecular medications must enter the target cell to be effective and obstacles in the systemic delivery of DNA or RNA limit their use in a clinical setting. The creation of nucleic acid delivery systems based on nanoparticles in order to circumvent biological constraints is advancing quickly. The ease of synthesis and surface modification, biocompatibility, biodegradability, cost-effectiveness and high loading capability of nucleic acids have prompted the use of mesoporous silica nanoparticles (MSNs) in gene therapy. The unique surface features of MSNs facilitate their design and decoration for high loading of nucleic acids, immune system evasion, cancer cell targeting, controlled cargo release, and endosomal escape. Reports have demonstrated successful therapeutic outcomes with the administration of a variety of engineered MSNs capable of delivering genes to tumor sites in laboratory animals. This comprehensive review of studies about siRNA, miRNA, shRNA, lncRNA and CRISPR/Cas9 delivery by MSNs reveals engineered MSNs as a safe and efficient system for gene transfer to cancer cells and cancer mouse models.

Fabricating a PDA-Liposome Dual-Film Coated Hollow Mesoporous Silica Nanoplatform for Chemo-Photothermal Synergistic Antitumor Therapy

In this study, we synthesized hollow mesoporous silica nanoparticles (HMSNs) coated with polydopamine (PDA) and a D-α-tocopheryl polyethylene glycol 1000 succinate (TPGS)-modified hybrid lipid membrane (denoted as HMSNs-PDA@liposome-TPGS) to load doxorubicin (DOX), which achieved the integration of chemotherapy and photothermal therapy (PTT). Dynamic light scattering (DLS), transmission electron microscopy (TEM), N₂ adsorption/desorption, Fourier transform infrared spectrometry (FT-IR), and small-angle X-ray scattering (SAXS) were used to show the successful fabrication of the nanocarrier. Simultaneously, in vitro drug release experiments showed the pH/NIR-laser-triggered DOX release profiles, which could enhance the synergistic therapeutic anticancer effect. Hemolysis tests, non-specific protein adsorption tests, and in vivo pharmacokinetics studies exhibited that the HMSNs-PDA@liposome-TPGS had a prolonged blood circulation time and greater hemocompatibility compared with HMSNs-PDA. Cellular uptake experiments demonstrated that HMSNs-PDA@liposome-TPGS had a high cellular uptake efficiency. In vitro and in vivo antitumor efficiency evaluations showed that the HMSNs-PDA@liposome-TPGS + NIR group had a desirable inhibitory activity on tumor growth. In conclusion, HMSNs-PDA@liposome-TPGS successfully achieved the synergistic combination of chemotherapy and photothermal therapy, and is expected to become one of the candidates for the combination of photothermal therapy and chemotherapy antitumor strategies.

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.

The emergence of nanoporous materials in lung cancer therapy

Lung cancer is one of the most common cancers, affecting more than 2.1 million people across the globe every year. A very high occurrence and mortality rate of lung cancer have prompted active research in this area with both conventional and novel forms of therapies including the use of nanomaterials based drug delivery agents. Specifically, the unique physico-chemical and biological properties of porous nanomaterials have gained significant momentum as drug delivery agents for delivering a combination of drugs or merging diagnosis with targeted therapy for cancer treatment. This review focuses on the emergence of nano-porous materials for drug delivery in lung cancer. The review analyses the currently used nanoporous materials, including inorganic, organic and hybrid porous materials for delivering drugs for various types of therapies, including chemo, radio and phototherapy. It also analyses the selected research on stimuli-responsive nanoporous materials for drug delivery in lung cancer before summarizing the various findings and projecting the future of emerging trends. This review provides a strong foundation for the current status of the research on nanoporous materials, their limitations and the potential for improving their design to overcome the unique challenges of delivering drugs for the treatment of lung cancer.

Engineering mesoporous silica nanoparticles for drug delivery: where are we after two decades?

The present review details a chronological description of the events that took place during the development of mesoporous materials, their different synthetic routes and their use as drug delivery systems. The outstanding textural properties of these materials quickly inspired their translation to the nanoscale dimension leading to mesoporous silica nanoparticles (MSNs). The different aspects of introducing pharmaceutical agents into the pores of these nanocarriers, together with their possible biodistribution and clearance routes, would be described here. The development of smart nanocarriers that are able to release a high local concentration of the therapeutic cargo on-demand after the application of certain stimuli would be reviewed here, together with their ability to deliver the therapeutic cargo to precise locations in the body. The huge progress in the design and development of MSNs for biomedical applications, including the potential treatment of different diseases, during the last 20 years will be collated here, together with the required work that still needs to be done to achieve the clinical translation of these materials. This review was conceived to stand out from past reports since it aims to tell the story of the development of mesoporous materials and their use as drug delivery systems by some of the story makers, who could be considered to be among the pioneers in this area.

Effect of (3-aminopropyl)triethoxysilane on dissolution of silica nanoparticles synthesized via reverse micro emulsion

Silica nanomaterials have been studied based on their potential applications in a variety of fields, including biomedicine and agriculture. A number of different molecules have been condensed onto silica nanoparticles' surfaces to present the surface chemistry needed for a given application. Among those molecules, (3-aminopropyl)triethoxysilane (APS) is one of the most commonly applied silanes used for nanoparticle surface functionalization to achieve charge reversal as well as to enable cargo loading. However, the colloidal stability of APS-functionalized silica nanoparticles has not been thoroughly studied, which can be problematic when the high reactivity of amine groups is considered. In this study, four different types of silica nanoparticles with varied location of added APS have been prepared via a reverse micro emulsion process, and their colloidal stability and dissolution behavior have been investigated. Systematic characterization has been accomplished using transmission electron microscopy (TEM), silicomolybdic acid (SMA) spectrophotometric assay, nitrogen adsorption-desorption surface area measurement, and aerosol ion mobility-mass spectrometry to track the nanoparticles' physical and chemical changes during dissolution. We find that when APS is on the interior of the silica nanoparticle, it facilitates dissolution, but when APS is condensed both on the interior and exterior, only the exterior siloxane bonds experience catalytic hydrolysis, and the interior dissolution is dramatically suppressed. The observation and analyses that silica nanoparticles show different hydrolysis behaviors dependent on the location of the functional group will be important in future design of silica nanoparticles for specific biomedical and agricultural applications.

Unique Properties of Surface-Functionalized Nanoparticles for Bio-Application: Functionalization Mechanisms and Importance in Application

This review tries to summarize the purpose of steadily developing surface-functionalized nanoparticles for various bio-applications and represents a fascinating and rapidly growing field of research. Due to their unique properties—such as novel optical, biodegradable, low-toxicity, biocompatibility, size, and highly catalytic features—these materials are considered superior, and it is thus vital to study these systems in a realistic and meaningful way. However, rapid aggregation, oxidation, and other problems are encountered with functionalized nanoparticles, inhibiting their subsequent utilization. Adequate surface modification of nanoparticles with organic and inorganic compounds results in improved physicochemical properties which can overcome these barriers. This review investigates and discusses the iron oxide nanoparticles, gold nanoparticles, platinum nanoparticles, silver nanoparticles, and silica-coated nanoparticles and how their unique properties after fabrication allow for their potential use in a wide range of bio-applications such as nano-based imaging, gene delivery, drug loading, and immunoassays. The different groups of nanoparticles and the advantages of surface functionalization and their applications are highlighted here. In recent years, surface-functionalized nanoparticles have become important materials for a broad range of bio-applications.

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.

Synthetic methods of lipid-coated mesoporous silica nanoparticles as drug carriers

The lipid-coated mesoporous silica nanoparticles (LMSNs) that can synergistically harness the advantages and mitigate the disadvantages of the liposomes and MSNs are considered potential drug carriers. So far, several methods have been developed to prepare LMSNs, including vesicle fusion, thin-film hydration, and solvent exchange. Despite their wide application in LMSN preparation, these methods are short of detailed elaboration and comparison, which hinders their further development. In this review, for the first time, the three methods are systematically summarized, including their mechanisms, influence factors, advantages, and limitations. Although these methods are all based on lipid self-assembly, there is still a difference between them. In order to efficiently prepare LMSNs, we proposed that a suitable method should be selected based on the actual situation. It is conceivable that the elaboration and comparison in this review will make these methods easy to be understood and provide guidance for the design of LMSNs as drug carriers.

Recent Advances of Mesoporous Silica as a Platform for Cancer Immunotherapy

Immunotherapy is a promising modality of treatment for cancer. Immunotherapy is comprised of systemic and local treatments that induce an immune response, allowing the body to fight back against cancer. Systemic treatments such as cancer vaccines harness antigen presenting cells (APCs) to activate T cells with tumor-associated antigens. Small molecule inhibitors can be employed to inhibit immune checkpoints, disrupting tumor immunosuppression and immune evasion. Despite the current efficacy of immunotherapy, improvements to delivery can be made. Nanomaterials such as mesoporous silica can facilitate the advancement of immunotherapy. Mesoporous silica has high porosity, decent biocompatibility, and simple surface functionalization. Mesoporous silica can be utilized as a versatile carrier of various immunotherapeutic agents. This review gives an introduction on mesoporous silica as a nanomaterial, briefly covering synthesis and biocompatibility, and then an overview of the recent progress made in the application of mesoporous silica to cancer immunotherapy.

Synthesis and characterization of amine-functionalized Fe3O4/Mesoporous Silica Nanoparticles (MSNs) as potential nanocarriers in drug delivery systems

Superparamagnetic Iron Oxide Nanoparticles (SPIONs) have shown great potential for being utilized in Nanocarriers (NCs) applications throughout the Drug Delivery System (DDS). However, there are several obstacles to make a practical magnetic NCs, such as low dispersity and high toxicity in the biological systems, and also low surface area for drug loading. In this work, magnetic NCs have been synthesized through a facile three-step process, first SPIONs were synthesized by the co-precipitation method, then decorated via mesoporous silica and finally the calcinated NCs functionalized with NH2 by a simple process in the ethanol solvent. The structure and morphology of the as-synthesized NCs have been characterized by the usage of different analyzing methods such as XRD, FTIR, TEM, FE-SEM, and TGA. Also, the magnetic properties have been investigated by the means of VSM throughout each step of the procedure. Lastly, we have applied the technique of N₂ adsorption-desorption to observe the surface area, pore size, and volume. Besides optimal magnetization of final nanoparticles (30 emu/gr), the as-synthesized NCs claimed the high surface area and small diameter, at 371 m².g^-1 and 70 nm, respectively. Moreover, the functionalized NCs have demonstrated well dispersity over a day in the PBS solution. As a result, the as-prepared nanocarrier able to overcome drug delivery obstacles and used as a potential nanocarrier owing to its small diameter, high surface area/ pore volume, optimal magnetization, and well dispersity in the biological condition.

Application of chitosan modified nanocarriers in breast cancer

As per the WHO, every year around 2.1 million women are detected with breast cancer. It is one of the most invasive cancer in women and second most among all, contributing around 15% of death worldwide. The available anticancer therapies including chemo, radio, and hormone therapy are associated with a high load of reversible and irreversible adverse effects, limited therapeutic efficacy, and low chances of quality survival. To minimize the side effects, improving therapeutic potency and patient compliance promising targeted therapies are highly desirable. In this sequence, various nanocarriers and target modified systems have been explored by researchers throughout the world. Among these chitosan-based nanocarriers offers one of the most interesting, flexible, and biocompatible systems. The unique characteristics of chitosan like surface flexibility, biocompatibility, hydrophilicity, non-toxic and cost-effective behavior assist to overcome the inadequacy of existing therapy. The present review throws light on the successes, failures, and current status of chitosan modified novel techniques for tumor targeting of bioactives. It also emphasizes the molecular classification of breast cancer and current clinical development of novel therapies. The review compiles most relevant works of the past 10 years focusing on the application of chitosan-based nanocarrier against breast cancer.

Novel strategies to improve tumour therapy by targeting the proteins MCT1, MCT4 and LAT1

Poor selectivity, potential systemic toxicity and drug resistance are the main challenges associated with chemotherapeutic drugs. MCT1 and MCT4 and LAT1 play vital roles in tumour metabolism and growth by taking up nutrients and are thus potential targets for tumour therapy. An increasing number of studies have shown the feasibility of including these transporters as components of tumour-targeting therapy. Here, we summarize the recent progress in MCT1-, MCT4-and LAT1-based therapeutic strategies. First, protein structures, expression, relationships with cancer, and substrate characteristics are introduced. Then, different drug targeting and delivery strategies using these proteins have been reviewed, including designing protein inhibitors, prodrugs and nanoparticles. Finally, a dual targeted strategy is discussed because these proteins exert a synergistic effect on tumour proliferation. This article concentrates on tumour treatments targeting MCT1, MCT4 and LAT1 and delivery techniques for improving the antitumour effect. These innovative tactics represent current state-of-the-art developments in transporter-based antitumour drugs.

Nano drug delivery systems improve metastatic breast cancer therapy

Despite continual progress in the technologies and regimens for cancer therapy, the treatment outcome of fatal metastatic breast cancer is far from satisfactory. Encouragingly, nanotechnology has emerged as a valuable tool to optimize drug delivery process in cancer therapy via preventing the cargos from degradation, improving the tumor-targeting efficiency, enhancing therapeutic agents' retention in specific sites, and controlling drug release. In the last decade, several mechanisms of suppressing tumor metastasis by functional nano drug delivery systems (NDDSs) have been revealed and a guidance for the rational design of anti-metastasis NDDSs is summarized, which consist of three aspects: optimization of physiochemical properties, tumor microenvironment remodeling, and biomimetic strategies. A series of medicinal functional biomaterials and anti-metastatic breast cancer NDDSs constructed by our team are introduced in this review. It is hoped that better anti-metastasis strategies can be inspired and applied in clinic.

Successively triggered Rod-shaped protocells for enhanced tumor Chemo-Photothermal therapy

Abundant existence of extracellular matrix biological hydrogels in solid tumors precludes most therapeutics to arrive at intracellular target sites, which is probably one of the threatened reasons of pancreatic ductal adenocarcinoma (PDAC) for public health. In this study, we designed a rod-shaped protocell nanoparticle loading with doxorubicin hydrochloride (Dox) and indocyanine green (ICG), denoted as Dox/ICG-RsPNs, for enhanced chemo-photothermal PDAC treatment. The enhanced therapeutic efficacy was achieved by successively enhancing penetration across matrix hydrogels, endocytosis, increasing local temperature under laser irradiation and hyperthermia-triggered Dox release to nucleus. We found that RsPNs with rod shape could easily penetrate across matrix hydrogel, exerting excellent tumor accumulation. Then RsPNs was internalized effectively by BxPC-3 cells via a caveolin-mediated endocytosis pathway. In addition, ICG endowed the Dox/ICG-RsPNs with photothermal effect and the photothermal conversion efficiency was calculated for 16.2%. Under irradiation, a great number of Dox transported to the nucleus via hyperthermia-induced release. Furthermore, we found that the relative tumor volume of Dox/ICG-RsPNs was merely 1.37 under irradiation at the end of pharmacodynamic studies, which was significantly lower than that of other groups. These findings will provide a promise on the rational design of drug delivery system for effective chemo-photothermal combination therapy to treat PDAC.

An Update on Mesoporous Silica Nanoparticle Applications in Nanomedicine

The efficient and safe delivery of therapeutic drugs, proteins, and nucleic acids are essential for meaningful therapeutic benefits. The field of nanomedicine shows promising implications in the development of therapeutics by delivering diagnostic and therapeutic compounds. Nanomedicine development has led to significant advances in the design and engineering of nanocarrier systems with supra-molecular structures. Smart mesoporous silica nanoparticles (MSNs), with excellent biocompatibility, tunable physicochemical properties, and site-specific functionalization, offer efficient and high loading capacity as well as robust and targeted delivery of a variety of payloads in a controlled fashion. Such unique nanocarriers should have great potential for challenging biomedical applications, such as tissue engineering, bioimaging techniques, stem cell research, and cancer therapies. However, in vivo applications of these nanocarriers should be further validated before clinical translation. To this end, this review begins with a brief introduction of MSNs properties, targeted drug delivery, and controlled release with a particular emphasis on their most recent diagnostic and therapeutic applications.

Rapid Purification of Immunoglobulin G Using a Protein A-​immobilized Monolithic Spin Column with Hydrophilic Polymers

A rapid purification method was developed for antibody production in Chinese hamster ovary (CHO) cells using a Protein A-immobilized monolithic silica spin column with hydrophilic polymers. Monolithic silica modified with copolymers of 2-hydroxyethylmethacrylate (HEMA) and glycidyl methacrylate (GMA) showed lower non-specific protein absorption than that modified with a silane reagent. The epoxy group of GMA was converted to an amino group, and Protein A was modified by the coupling reagent. The amount of immobilized Protein A was controlled by changing the ratio of GMA to HEMA and the mesopore size of monolith. A modified monolith disk was fixed to a spin column for rapid antibody purification. The linear curves (for the antibody concentrations over 10 - 300 μg/mL) had a correlation coefficient of >0.999. Our column had various analytical advantages over previously reported columns, including a shorter preparation time (<10 min) and smaller sample volumes for purification with Protein A-immobilized agarose.

Antioxidative Activity of Soy, Wheat and Pea Protein Isolates Characterized by Multi-Enzyme Hydrolysis

Hydrolysis of protein by proteases produces small molecular weights (MWs) peptides as nanomaterials that are easily absorbed. This study investigated the physicochemical properties and antioxidant activity of three plant protein isolates (PIs) including soy, wheat and pea after multi-enzyme hydrolysis. The MWs, particle size and microstructure of PI hydrolysate (PIH) were determined by SDS-PAGE and MALDI-TOF-MS mass spectrometry, dynamic light scattering and transmission electron microscopy, respectively. Cell viability was determined in vitro using a mouse skeletal muscle cell line (C2C12) and crystal violet staining. The MWs and particle sizes of the three plant PIs were reduced after hydrolysis by three proteases (bromelain, Neutrase and Flavourzyme). The MWs of soy, wheat and pea PIH were 103.5–383.0 Da, 103.5–1146.5 Da and 103.1–1937.7 Da, respectively, and particle size distributions of 1.9–2.0 nm, 3.2–5.6 nm and 1.3–3.2 nm, respectively. All three plant PIHs appeared as aggregated nanoparticles. Soy PIH (100 μg/mL) provided better protection against H₂O₂-induced oxidative damage to C2C12 than wheat or pea PIH. In summary, soy PIH had the best antioxidant activity, and particle size than wheat PIH and pea PIH. Therefore, soy PIH might be a dietary supplement for healthy diet and medical applications.

Current Status and Emerging Trend of Nanoshuttle in Biological Applications

Nanoshuttles are unique structures that resemble double-headed arrows or a nanorod with sharp tips for better penetration into the tumor cells, reduction of toxicity and minimization of off-targeting effect. These biologically- inspired multimetallic or bimetallic nano swimmers are capable of transporting cargoes from one end to another via self-propulsion in an efficient manner. Encapsulation with pH- and heat-sensitive polymers allows nanoshuttles to release cargos at the targeted site in a controlled fashion. This review article focuses on the methods of preparation and characterization of nanoshuttles with applications in the field of antineoplastic, antibacterial, erectile dysfunction, electrochemical biosensing, anticounterfeiting, on-demand and targeted delivery system for imaging as well as cell ablation therapy. Magnetic nanoshuttles exhibit modified optical properties for utilization in diagnostic imaging for sensitive and early diagnosis of diseases. Smart drug delivery is achieved when nanoshuttles are combined with nanomotors to exhibit distinctive, rapid and unidirectional movement in the bloodstream. Cost-effective synthesis of nanoshuttles will extend their applications in the commercial sectors by overcoming the limitations like scale-up and regulatory approval. In the near future, nanoshuttles will diversify in the fields of energy conversion, energy storage, 3D printing, stem cell fabrication and theranostics.

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.

Physicochemical and Antioxidative Characteristics of Potato Protein Isolate Hydrolysate

This study investigated the physicochemical characteristics of potato protein isolate hydrolysate (PPIH) and its antioxidant activity. Potato protein isolate (PPI) was hydrolyzed into PPIH by the proteases bromelain, Neutrase, and Flavourzyme. Compared with PPI, the resulting PPIH had a lower molecular weight (MW, from 103.5 to 422.7 Da) and smaller particle size (<50 nm), as well as a higher solubility rate (>70%) under acidic conditions (pH 3–6). PPIH presented good solubility (73%) across the tested pH range of 3–6. As the pH was increased, the zeta potential of PPIH decreased from −7.4 to −21.6. Using the 2,2′-azino-bis-3-ethylbenzthiazoline-6-sulfonic acid (ABTS) radical-scavenging assay, we determined that the half-maximal effective concentration (EC₅₀) values of ascorbic acid, PPIH, and PPI were 0.01, 0.89, and >2.33 mg/mL, respectively. Furthermore, PPIH (50 μg/mL) protected C2C12 cells from H₂O₂ oxidation significantly better than PPI (10.5% higher viability rate; p < 0.01). These findings demonstrated the possible use of PPIH as an antioxidant in medical applications.

Mesoporous silica nanoparticles: synthesis methods and their therapeutic use-recent advances

Mesoporous silica nanoparticles (MSNPs) are a particular example of innovative nanomaterials for the development of drug delivery systems. MSNPs have recently received more attention for biological and pharmaceutical applications due to their capability to deliver therapeutic agents. Due to their unique structure, they can function as an effective carrier for the delivery of therapeutic agents to mitigate diseases progress, reduce inflammatory responses and consequently improve cancer treatment. The potency of MSNPs for the diagnosis and management of various diseases has been studied. This literature review will take an in-depth look into the properties of various types of MSNPs (e.g. shape, particle and pore size, surface area, pore volume and surface functionalisation), and discuss their characteristics, in terms of cellular uptake, drug delivery and release. MSNPs will then be discussed in terms of their therapeutic applications (passive and active tumour targeting, theranostics, biosensing and immunostimulative), biocompatibility and safety issues. Also, emerging trends and expected future advancements of this carrier will be provided.

Targeted GSH-exhausting and hydroxyl radical self-producing manganese-silica nanomissiles for MRI guided ferroptotic cancer therapy

Ferroptosis, a cell death path induced by the generation of reactive oxygen species (ROS), will cause the accumulation of lipid peroxides (PL-PUFA-OOH) and achieve potent tumor-regression. However, glutathione (GSH)-dependent glutathione peroxidase 4 (GPx4) can reduce PL-PUFA-OOH and antagonize the ferroptosis inducing effect of ROS. Herein, folate-PEG modified dihydroartemisinin (DHA) loaded manganese doped mesoporous silica nanoparticles (described as nanomissiles) were constructed for integrating the effect of GSH exhaustion and ROS generation. After endocytosis by tumor cells, intracellular GSH triggered the degradation of nanomissiles, which allowed the simultaneous release of DHA and Fenton catalytic Mn2+ due to the redox reaction between the manganese-oxygen bonds and GSH. The degradation would lead to GSH exhaustion, activation of Mn2+-based magnetic resonance imaging (MRI), and DHA-driven ˙OH generation. The GSH-free environment inhibited the activity of GPx4 and enhanced the accumulation of PL-PUFA-OOH oxidized by ˙OH. Furthermore, the cooperative effects suppressed tumor metastasis by destroying the structure of polyunsaturated fatty acids in the cell membranes and showed potent antitumor activity. This innovative ferroptotic therapy integrating the GSH exhaustion and ROS generation will be a promising strategy for cancer therapy.

Synergistic co-delivery of diacid metabolite of norcantharidin and ABT-737 based on folate-modified lipid bilayer-coated mesoporous silica nanoparticle against hepatic carcinoma

Diacid metabolite as the stable form of norcantharidin (DM-NCTD) derived from Chinese blister beetle (Mylabris spp.). The previous studies reported that DM-NCTD could enhance ABT-737-triggered cell viability inhibition and apoptosis in hepatocellular carcinoma (HCC) cell lines. To translate this synergistic therapy into in vivo anticancer treatment, a folate receptor-targeted lipid bilayer-supported chlorodimethyloctadecylsilane-modified mesoporous silica nanoparticle (FA-LB-CHMSN) with DM-NCTD loaded in CHMSN and ABT-737 in lipid bilayer was prepared, which could promote the cancer cell uptake of the drugs through folate receptor-mediated endocytosis. The structure and the properties of the nanoparticle were evaluated. FA-LB-CHMSN with DM-NCTD/ABT-737 loaded induced apparent tumor cell apoptosis and showed remarkably tumor inhibition in H22 tumor-bearing mice model, with significant cellular apoptosis in the tumor and no obvious toxicity to the tissues. We expect that this nanoparticle could be of interest in both biomaterial investigations for HCC treatment and the combination of chemotherapeutic drugs for synergistic therapies.

Silica-Based Gene Delivery Systems: From Design to Therapeutic Applications

Advances in gene therapy have been foreshadowing its potential for the treatment of a vast range of diseases involving genetic malfunctioning. However, its therapeutic efficiency and successful outcome are highly dependent on the development of the ideal gene delivery system. On that matter, silica-based vectors have diverted some attention from viral and other types of non-viral vectors due to their increased safety, easily modifiable structure and surface, high stability, and cost-effectiveness. The versatility of silane chemistry and the combination of silica with other materials, such as polymers, lipids, or inorganic particles, has resulted in the development of carriers with great loading capacities, ability to effectively protect and bind genetic material, targeted delivery, and stimuli-responsive release of cargos. Promising results have been obtained both in vitro and in vivo using these nanosystems as multifunctional platforms in different potential therapeutic areas, such as cancer or brain therapies, sometimes combined with imaging functions. Herein, the current advances in silica-based systems designed for gene therapy are reviewed, including their main properties, fabrication methods, surface modifications, and potential therapeutic applications.

Folic acid modified lipid-bilayer coated mesoporous silica nanoparticles co-loading paclitaxel and tanshinone IIA for the treatment of acute promyelocytic leukemia

In this work, paclitaxel (Ptx) combined with tanshinone IIA (TanIIA) was found to show synergistic effect on inducing apoptosis of human acute promyelocytic leukemia (APL) cell line NB₄, and the anti-tumor effect was strongest when its molar ratio was 1:1. To enhance the efficacy and reduce side effects, an active targeting drug delivery system with mesoporous silica nanoparticles (MSNs) coated with folic acid (FA) modified PEGylated lipid-bilayer (LB) membrane (FA-LB-MSNs) was established for co-loading drugs. The drug loadings of Ptx and TanIIA in FA-LB-MSNs were 5.5% and 1.8%, respectively. Compared with the uncoated MSNs, the FA-LB-MSNs showed a sustained drug release, and Ptx and TanIIA released synchronously from the carriers. By means of biological adhesion between FA and its receptors, the uptake of FA-LB-MSNs by NB₄ cells was significantly higher than that of uncoated preparations, and Ptx combined with TanIIA had strong synergistic effect to enhance the apoptosis and differentiation of NB₄ cells. The results of pharmacodynamics in vivo showed that the FA-LB-MSNs targeted tumor in nude mice more effectively than the compared formulations without FA modification. The Ptx and TanIIA-loaded FA-LB-MSNs group showed significantly better effects on inducing apoptosis and inhibiting tumor growth than the reference groups, which agreed with the results of anti-tumor experiments in vitro. Furthermore, no toxicity was observed to the heart, liver, spleen, lung and kidney of the tumor-bearing animals, indicating good biocompatibility of the prepared novel nanocarriers. This study confirmed the synergistic therapeutic effect of Ptx and TanIIA on APL, and the superior of FA-LB-MSNs as co-loaded nanocarriers for active targeted therapy of tumors.

Interaction of Hydrophobic Tungsten Cluster Complexes with a Phospholipid Bilayer

Nanoconstructions composed of lipid vesicles and inorganic units (nanoparticles, metal complexes) arouse much interest across materials science and nanotechnology as hybrid materials combining useful functionalities from both parts. Ideally, these units are to be embedded into the bilayer to keep the biophysical performance of lipid vesicles having inorganic moieties screened from the environment. This can be achieved by doping a lipid bilayer with cluster complexes of transition metals. In this work, we report the preparation of nanoparticles from trinuclear W₃S₄ cluster complexes and egg phosphatidylcholine. A systematic study of their properties was performed by the differential scanning calorimetry, NMR spectroscopy, dynamic light scattering, and transmission electron microscopy. Phospholipids and clusters have been found to spontaneously self-assemble into novel cluster-lipid hybrid materials. The behavior of clusters in the hydrophobic lipid environment is determined by the structure of the ligands and cluster-to-lipid ratio. Intact cluster complexes bearing compact hydrophobic ligands are embedded into the hydrophobic midplane of a lipid bilayer, whereas cluster complexes bearing larger ligands drive the aggregation of lipids and cluster complexes. Considering these differences, it could be possible to obtain different self-assembled associates such as cluster-doped liposomes or lipid-covered crystals. These cluster-lipid hybrids can be a platform for the design of new materials for nanotechnology.

Insights into the Cellular Uptake, Cytotoxicity, and Cellular Death Modality of Phospholipid-Coated Gold Nanorods toward Breast Cancer Cell Lines

Gold nanorods (GNRs) have gained pronounced recognition in the diagnosis and treatment of cancers driven by their distinctive properties. Herein, a gold-based nanosystem was prepared by utilizing a phospholipid moiety linked to thiolated polyethylene glycol, 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-PEG-SH, as a surface decorating agent. The synthesized phospholipid-PEG-GNRs displayed good colloidal stability upon exposure to the tissue culture medium. Cytotoxicity of phospholipid-PEG-GNRs was investigated toward MCF-7 and T47D breast cancer cells using sulforhodamine B test. The results revealed that phospholipid-PEG-GNRs demonstrated  high cytotoxicity to MCF-7 cells compared to T47D cells, and minimal cytotoxicity to human dermal fibroblasts. The cellular uptake studies performed by imaging and quantitative analysis demonstrated  massive internalization of phospholipid-coated GNRs into  MCF-7 cells in comparison to T47D cells. The cellular death modality of cancer cells after treatment with phospholipid-PEG-GNRs was evaluated using mitochondrial membrane potential assay (JC-1 dye), gene expression analysis, and flow cytometry study. The overall results suggest that phospholipid-modified GNRs enhanced mainly the cellular apoptotic events in MCF-7 cells in addition to necrosis, whereas cellular necrosis and suppression of cellular invasion contributed to the cellular death modality in the T47D cell line upon treatment with phospholipid-PEG-GNRs. The phospholipid-coated GNRs interact in a different manner with breast cancer cell lines and could be considered for breast cancer treatment.

Functionalized mesoporous silica nanoparticles in anticancer therapeutics

The application of nanomedicines in tumor targeting and attaining meaningful therapeutic benefits for the treatment of cancers has been going on for almost two decades. Beyond the lipidic and polymeric nanomedicines-based passive and active targeting, the quest for inventing the new generation of carriers has no end. This has lead to the evolution of some of the unique carrier systems with supramolecular assembly structures. Mesoporous nanoparticulate systems (MSNPs) are the recently explored substances with favorable potential for drug delivery and drug targeting applications especially in cancer chemotherapeutics. Notwithstanding their physical properties that makes them a suitable carrier for cancer treatment, but their outstanding ability towards chemical functionalization helps in delivering the imaging agents for diagnostic applications. MSNPs can improve the dissolution rate and systemic availability of the poorly water soluble drugs due to their mesoporous structures. Besides, guest molecules including targeting ligands, biomimetic agents, fluorescent dyes, and biocompatible polymers can be efficiently encapsulated in their tunable porous structure for targeting purpose. Some special features of the MSNPs which make them one of the highly effective nanocarrier systems include their ability to encapsulate non-crystalline drugs in their mesopores, high dispersion ability as a function of large surface area and wetting properties. For anticancer drug delivery, MSNPs are worthful to provide excellent drug loading capacity and endocytotic behavior. Moreover, the external surface of MSNPs can be precisely modified for tumor-recognition and developing sensitivity of the antitumor agents towards the cancer cells. Owing to the innumerable applications of MSNPs till now in cancer treatment, the present article particularly focuses to provide an overview account with complete details on the topic to make the readers abreast with details on physiochemical and material properties of MSNPs, their applications and current innovations for the purpose.

Naturally Occurring and Synthetic Mesoporous Nanosilica: Multimodal Applications in Frontier Areas of Science

Mesoporous silica nanoparticles (MSNs) have gained attention worldwide due to their structural versatility for diverse applications in a number of frontier areas of sciences. The intrinsic chemical, textural and structural features of MSNs allow fabricating versatile multifunctional nanosystems. The present review provides an overview of the research progress in artificial and biological production of MSNs, their properties and various applications in cutting edge areas of sciences.

Preferential Accumulation of Phospholipid-PEG and Cholesterol-PEG Decorated Gold Nanorods into Human Skin Layers and Their Photothermal-Based Antibacterial Activity

Herein, a library of gold nanorods (GNR) decorated with polyethylene glycol-thiol (PEG-SH) containing different functionalities were synthesized and characterized by optical absorption spectroscopy, zeta potential, dynamic light scattering (DLS), transmission electron microscope (TEM) and proton nuclear magnetic resonance (1H-NMR). The colloidal stability of GNR when exposed to skin, and their preferential accumulation into excised human skin layers were investigated. Confocal laser scanning microscopy, transmission electron microscope (TEM) and inductively coupled plasma-optical emission spectroscopy (ICP-OES) were utilized to track the penetration of GNR into different skin layers. The results demonstrated that cholesterol-PEG coated GNR were preferentially loaded up in the upper layers of skin (stratum corneum), while phospholipid-PEG coated counterparts were drastically deposited in skin dermis. Neutral methoxy-PEG-coated GNR were distributed in both SC and dermis skin layers, while charged GNR (anionic-carboxylic acid-PEG-GNR and cationic-amine-PEG-GNR) revealed a minimal accumulation into skin. DSPE-PEG-GNR and Chol-PEG-GNR demonstrated antibacterial activities against Staphylococcus aureus (S aureus) at MIC values of 0.011 nM and 0.75 nM, respectively. Photothermal treatment for S. aureus at sub-MIC concentrations resulted in a significant bactericidal effect when using Chol-PEG-GNR but not DSPE-PEG-GNR. Gold-based nanoscale systems have great value as a promising platform for skin diseases therapy.

Smart Mesoporous Silica Nanoparticles for Protein Delivery

Mesoporous silica nanoparticles (MSN) have attracted a lot of attention during the past decade which is attributable to their versatile and high loading capacity, easy surface functionalization, excellent biocompatibility, and great physicochemical and thermal stability. In this review, we discuss the factors affecting the loading of protein into MSN and general strategies for targeted delivery and controlled release of proteins with MSN. Additionally, we also give an outlook for the remaining challenges in the clinical translation of protein-loaded MSNs.

Bioceramics: from bone substitutes to nanoparticles for drug delivery

Since the second half of the 20th century, bioceramics are used for bone repair and regeneration. Inspired by bones and teeth, and aimed at mimicking their structure and composition, several artificial bioceramics were developed for biomedical applications. And nowadays, in the 21st century, with the increasing prominence of nanoscience and nanotechnology, certain bioceramics are being used to build smart drug delivery systems, among other applications. This minireview will mainly describe both tendencies through the research work carried out by the research team of María Vallet-Regí.

Nanostructured carriers as innovative tools for cancer diagnosis and therapy

Cancer accounts for millions of deaths every year and, due to the increase and aging of the world population, the number of new diagnosed cases is continuously rising. Although many progresses in early diagnosis and innovative therapeutic protocols have been already set in clinical practice, still a lot of critical aspects need to be addressed in order to efficiently treat cancer and to reduce several drawbacks caused by conventional therapies. Nanomedicine has emerged as a very promising approach to support both early diagnosis and effective therapy of tumors, and a plethora of different inorganic and organic multifunctional nanomaterials have been ad hoc designed to meet the constant demand for new solutions in cancer treatment. Given their unique features and extreme versatility, nanocarriers represent an innovative and easily adaptable tool both for imaging and targeted therapy purposes, in order to improve the specific delivery of drugs administered to cancer patients. The current review reports an in-depth analysis of the most recent research studies aiming at developing both inorganic and organic materials for nanomedical applications in cancer diagnosis and therapy. A detailed overview of different approaches currently undergoing clinical trials or already approved in clinical practice is provided.

Charge-Selective Delivery of Proteins Using Mesoporous Silica Nanoparticles Fused with Lipid Bilayers

Efficient and safe intracellular delivery of proteins is highly desired in the development of protein therapeutics. Current methods of protein delivery commonly suffer from low loading efficiency, low stability in serum, and lack of versatility for different proteins. Here, we developed a platform for efficient protein delivery using mesoporous silica nanoparticles (MSN) with lipid fusion. By different surface modifications on MSN, the positively charged MSN (MSN⁺) and the negatively charged MSN (MSN^-), were generated for loading different proteins. The cargo proteins, based on the surface charges, can be selectively loaded in very high efficiency. The protein-loaded MSNs were fused with liposomes to form a protocell-like delivery system (MSN-LP) in order to prevent burst release of proteins. The lipid fusion significantly increases the stability of the nanosystem in physiological conditions, and the MSN-LP protocell can efficiently deliver proteins into cells. The cargo proteins can be released in cells in a sustained manner. Fifteen different proteins, including two protein complexes, were tested using this delivery system. Further analyses indicate that the proteins can maintain their functions after delivery into cells. Fluorescent proteins, GFP, and KillerRed show fluorescence in cells, indicating the correct folding of proteins during encapsulation and delivery. Protein activity analysis shows that KillerRed protein can generate ROS in cells, while SOD can eliminate ROS in cells. Hence, the proteins delivered by this system remain their structure and function in cells. This work provides a versatile strategy for charge-selective delivery of proteins with high loading efficiency and high stability.

Angiopep-2-Conjugated "Core-Shell" Hybrid Nanovehicles for Targeted and pH-Triggered Delivery of Arsenic Trioxide into Glioma

The poor capability of drugs to permeate through the blood-brain barrier (BBB) and further release inside glioma greatly limits the curative effects of glioma chemotherapies. In this study, we prepared angiopep-2-conjugated liposome-silica hybrid nanovehicles for targeted delivery and increased the permeation of arsenic trioxide (ATO) in glioma. Polyacrylic acid (PAA) was grafted on mesoporous silica nanoparticles (MSN) for pH-sensitive release and supporting the lipid membrane. The prepared "core-shell" nanovehicles (ANG-LP-PAA-MSN) were characterized with uniform size, high drug loading efficiency (8.19 ± 0.51%), and superior pH-sensitive release feature. From the experiments, the enhanced targeted delivery of ATO by ANG-LP-PAA-MSN (ANG-LP-PAA-MSN@ATO) was evidenced by the improvement of transport, enhanced cellular uptake, and apoptosis in vitro. In addition, the pharmacokinetic study was creatively carried out through the blood-glioma synchronous microdialysis and revealed that the half-life ( t_1/2) of blood and glioma tissue in the ANG-LP-PAA-MSN@ATO treatment group was extended by 1.65 and 2.34 times compared with the ATO solution group (ATO-Sol). The targeting efficiency of ANG-LP-PAA-MSN@ATO (24.96%) was dramatically stronger than that of the ATO-Sol (5.94%). Importantly, ANG-LP-PAA-MSN@ATO had a higher accumulation (4.6 ± 2.6% ID per g) in tumor tissues and showed a better therapeutic efficacy in intracranial C6 glioma bearing rats. Taken together, the blood-glioma synchronous microdialysis was successful used for the pharmacokinetic study and real-time monitoring of drug concentrations in blood and glioma; ANG-LP-PAA-MSN could be a promising targeted drug delivery system for glioma therapy.

Influence of serum concentration and surface functionalization on the protein adsorption to mesoporous silica nanoparticles

A study of a protein corona on mesoporous silica nanoparticles (MSNs) at in vitro and in vivo relevant serum concentrations is presented. Three MSNs different in terms of mesoscopic pore arrangement, surface chemistry, and surface roughness were studied. After incubation in either 10% or 100% serum, the hard protein corona–particle complexes were collected and analyzed by DLS, zeta-potential, and TGA, and the corona proteins were analyzed with SDS-PAGE. A good correlation between SDS-PAGE and TG results in terms of total amounts of proteins adsorbed was established. The results demonstrated that more proteins, especially apolipoproteins, were associated with the particles at higher serum concentration regardless of surface chemistry and morphological differences. Also, the mean molecular weight of the adsorbed proteins was clearly lower under full serum conditions modeling in vivo conditions as compared to under dilute conditions modeling in vitro conditions, but functionalization of the MSNs by carboxylic acid functionalities reduced protein adsorption. The influence of the structural characteristics of the MSNs on the protein adsorption was minor.

In this work, protein adsorption on MSNs at in vitro (10%) and in vivo (100%) relevant serum concentrations was studied using three types of MSNs and their functional derivatives.

Photo-responsive magnetic mesoporous silica nanocomposites for magnetic targeted cancer therapy

A drug delivery platform for enhancing lung cancer treatment with controlled drug release, magnetic targeting and specific cancer cells targeting.

Lipid-Coated Mesoporous Silica Nanoparticles for the Delivery of the ML336 Antiviral to Inhibit Encephalitic Alphavirus Infection

Venezuelan equine encephalitis virus (VEEV) poses a major public health risk due to its amenability for use as a bioterrorism agent and its severe health consequences in humans. ML336 is a recently developed chemical inhibitor of VEEV, shown to effectively reduce VEEV infection in vitro and in vivo. However, its limited solubility and stability could hinder its clinical translation. To overcome these limitations, lipid-coated mesoporous silica nanoparticles (LC-MSNs) were employed. The large surface area of the MSN core promotes hydrophobic drug loading while the liposome coating retains the drug and enables enhanced circulation time and biocompatibility, providing an ideal ML336 delivery platform. LC-MSNs loaded 20 ± 3.4 μg ML336/mg LC-MSN and released 6.6 ± 1.3 μg/mg ML336 over 24 hours. ML336-loaded LC-MSNs significantly inhibited VEEV in vitro in a dose-dependent manner as compared to unloaded LC-MSNs controls. Moreover, cell-based studies suggested that additional release of ML336 occurs after endocytosis. In vivo safety studies were conducted in mice, and LC-MSNs were not toxic when dosed at 0.11 g LC-MSNs/kg/day for four days. ML336-loaded LC-MSNs showed significant reduction of brain viral titer in VEEV infected mice compared to PBS controls. Overall, these results highlight the utility of LC-MSNs as drug delivery vehicles to treat VEEV.

l-Arginine-Catalyzed Synthesis of Nanometric Organosilica Particles through a Waterborne Sol-Gel Process and Their Porous Structure Analysis

We report an efficient and easy-to-implement waterborne sol-gel process for the synthesis of nanometric organosilica particles. In this process, tetraethyl orthosilicate (TEOS) and 3-(methacryloxy)propyl trimethoxy silane (γ-MPS), employed as silica sources, were heterogeneously delivered in an aqueous solution of l-arginine, a basic amino acid used as a catalyst, from a top organic layer. Co-condensation of TEOS with γ-MPS led to the formation of organosilica particles with diameters between 30 and 230 nm when increasing the γ-MPS content from 0 to 10.1 mol % in the silica source. Nitrogen sorption analyses confirmed the microporous nature of the obtained particles after calcination. The Brunauer-Emmett-Teller (BET) surface areas increased from 27 (before calcination) to 684 m² g^-1 (after calcination) for the organosilica particles containing 10.1 mol % of γ-MPS. Fourier transform infrared spectroscopy and ²⁹Si NMR were employed to analyze the chemical structure of the organosilica spheres and provide insight into the mechanism of particle formation. In the second part, hybrid organosilica particles with a core-shell morphology were synthesized through the combination of Pickering emulsion and the sol-gel process. γ-MPS emulsion droplets stabilized by tiny silica particles (formed in a separate step) were first generated and used as seeds to grow a silica shell on their surface through TEOS addition from the top organic layer. Transmission electron microscopy and pore size analyses of the resulting particles after calcination revealed a unique dual-porosity structure with a mesoporous inner core and a micro/mesoporous silica shell with ink-bottle-type pores.