Polymeric functionalization of mesoporous silica nanoparticles: Biomedical insights

Mesoporous silica nanoparticles (MSNs) endowed with polymer coatings present a versatile platform, offering notable advantages such as targeted, pH-controlled, and stimuli-responsive drug delivery. Surface functionalization, particularly through amine and carboxyl modification, enhances their suitability for polymerization, thereby augmenting their versatility and applicability. This review delves into the diverse therapeutic realms benefiting from polymer-coated MSNs, including photodynamic therapy (PDT), photothermal therapy (PTT), chemotherapy, RNA delivery, wound healing, tissue engineering, food packaging, and neurodegenerative disorder treatment. The multifaceted potential of polymer-coated MSNs underscores their significance as a focal point for future research endeavors and clinical applications. A comprehensive analysis of various polymers and biopolymers, such as polydopamine, chitosan, polyethylene glycol, polycaprolactone, alginate, gelatin, albumin, and others, is conducted to elucidate their advantages, benefits, and utilization across biomedical disciplines. Furthermore, this review extends its scope beyond polymerization and biomedical applications to encompass topics such as surface functionalization, chemical modification of MSNs, recent patents in the MSN domain, and the toxicity associated with MSN polymerization. Additionally, a brief discourse on green polymers is also included in review, highlighting their potential for fostering a sustainable future.

Specific and efficient knockdown of intracellular miRNA using partially neutralized phosphate-methylated DNA oligonucleic acid-loaded mesoporous silica nanoparticles

Antisense oligonucleotides (ASOs) are molecules used to regulate RNA expression by targeting specific RNA sequences. One specific type of ASO, known as neutralized DNA (nDNA), contains site-specific methyl phosphotriester (MPTE) linkages on the phosphate backbone, changing the negatively charged DNA phosphodiester into a neutralized MPTE with designed locations. While nDNA has previously been employed as a sensitive nucleotide sequencing probe for the PCR, the potential of nDNA in intracellular RNA regulation and gene therapy remains underexplored. Our study aims to evaluate the regulatory capacity of nDNA as an ASO probe in cellular gene expression. We demonstrated that by tuning MPTE locations, partially and intermediately methylated nDNA loaded onto mesoporous silica nanoparticles (MSNs) can effectively knock down the intracellular miRNA, subsequently resulting in downstream mRNA regulation in colorectal cancer cell HCT116. Additionally, the nDNA ASO-loaded MSNs exhibit superior efficacy in reducing miR-21 levels over 72 hours compared to the efficacy of canonical DNA ASO-loaded MSNs. The reduction in the miR-21 level subsequently resulted in the enhanced mRNA levels of tumour-suppressing genes PTEN and PDCD4. Our findings underscore the potential of nDNA in gene therapies, especially in cancer treatment via a fine-tuned methylation location.

Effect of Amine, Carboxyl, or Thiol Functionalization of Mesoporous Silica Particles on Their Efficiency as a Quercetin Delivery System in Simulated Gastrointestinal Conditions

Quercetin (Q) dietary supplements exhibit poor oral bioavailability because of degradation throughout gastrointestinal digestion (GD), which may be overcome using mesoporous silica particles (MSPs) as an oral delivery system (ODS). This study aimed to elucidate the effect of the functionalization of MSPs with amine-(A-MSP), carboxyl-(C-MSP), or thiol-(T-MSP) groups on their efficiency as a quercetin ODS (QODS). The type and degree of functionalization (DF) were used as factors in an experimental design. The Q-loaded F-MSP (F-MSP/Q) was characterized by gas physisorption analysis, loading capacity (LC), and dynamic light scattering and kinetics of Q release at gastric and intestinal pHs. Antioxidant capacity and Q concentration of media containing F-MSP/Q were evaluated after simulated GD. A-MSP showed the highest LC (19.79 ± 2.42%). C-MSP showed the lowest particle size at pH 1.5 or 7.4 (≈200 nm). T-MSP exhibited the maximum Q release at pH 7.4 (11.43%). High DF of A-MSP increased Q retention, regardless of pH. A-MSP preserved antioxidant capacity of Q-released gastric media (58.95 ± 3.34%). Nonetheless, MSP and F-MSP did not protect antioxidant properties of Q released in intestinal conditions. C-MSP and T-MSP showed essential features for cellular uptake and Q release within cells that need to be assessed.

Theranostics: a multifaceted approach utilizing nano-biomaterials

Biomaterials play a vital role in targeting therapeutics. Over the years, several biomaterials have gained wide attention in the treatment and diagnosis of diseases. Scientists are trying to make more personalized treatments for different diseases, as well as discovering novel single agents that can be used for prognosis, medication administration, and keeping track of how a treatment works. Theranostics based on nano-biomaterials have higher sensitivity and specificity for disease management than conventional techniques. This review provides a concise overview of various biomaterials, including carbon-based materials like fullerenes, graphene, carbon nanotubes (CNTs), and carbon nanofibers, and their involvement in theranostics of different diseases. In addition, the involvement of imaging techniques for theranostics applications was overviewed. Theranostics is an emerging strategy that has great potential for enhancing the accuracy and efficacy of medicinal interventions. Despite the presence of obstacles such as disease heterogeneity, toxicity, reproducibility, uniformity, upscaling production, and regulatory hurdles, the field of medical research and development has great promise due to its ability to provide patients with personalised care, facilitate early identification, and enable focused treatment.

Diatom-derived mesoporous silica nanoparticles loaded with fucoidan for enhanced chemo-photodynamic therapy

Combination therapy merges chemical photodynamic therapy (CPDT) to improve cancer treatment. It synergizes chemotherapy with photodynamic therapy (PDT), using photosensitizers to produce reactive oxygen species (ROS) when exposed to light, effectively killing drug-resistant cancer cells. It is not affected by drug resistance, making it an attractive option for combination with chemotherapy. In this study, the focus was on the design of a combination therapy of chemotherapy and PDT. They synthesized diatomaceous earth mesoporous silica nanoparticles (dMSN) containing lanthanide metal ions in a PDT composition. These nanoparticles can generate ROS under near-infrared light irradiation and have MRI and fluorescence imaging capabilities, confirming their phototherapeutic effect on HCT116 cancer cells at a 200 μg/mL concentration. Fucoidan, derived from brown algae, was used as the chemotherapy component. The fucoidan extracted from Sargassum oligocystum in Pingtung Haikou showed the highest anticancer activity, with cell viability of 57.4 % at 200 μg/mL on HCT116 cancer cells. For combination therapy, fucoidan was loaded into nanoparticles (dMSN-EuGd@fucoidan). Cell viability experiments revealed that at 200 μg/mL, the cell survival rate of dMSN-EuGd@Fucoidan on HCT116 cancer cells was 47.7 %. Combination therapy demonstrated superior anticancer efficacy compared to PDT or chemotherapy alone, successfully synthesizing nanoparticles for combined chemotherapy and photodynamic therapy.

Development of a multifunctional platform for near-infrared imaging and targeted radionuclide therapy for tumors

Biotin receptor (BR) is overexpressed in several human tumor cell lines and has become an important biomarker for tumor diagnosis and treatment. Therefore, much attention has been attracted in the field of developing BR-targeting agents. In clinical practice, a multifunctional platform that can be used for both diagnosis and treatment is much desirable. In this study, to improve diagnostic and therapeutic efficacy of BR-positive tumors, we developed a multifunctional platform RT-H₂ to combine with the cyanine scaffold for near infrared (NIR) imaging and the radioisotope ¹³¹I for targeted radionuclide therapy (TRT). In vitro experiments showed that RT-H₂ possessed favorable NIR properties and could selectively accumulate in BR-positive HeLa cells. In vivo NIR imaging of HeLa tumor-bearing mice exhibited high accumulation and long retention time (72 h) of RT-H₂ in the tumor. Furthermore, RT-H₂ was also employed as a carrier to develop ¹³¹I-labeled TRT agent due to its favorable properties in vivo. The radiolabeling conditions were optimized and the optimal conditions determined to be 1.2 equiv of Idogen, reaction time 4 min and room temperature, yielding the radiotracer [¹³¹I]I-RT-H₂ with the radiochemical purity (RCP) of > 95% after a simple purification by a C18 column. In vitro cell experiments indicated that [¹³¹I]I-RT-H₂ could specifically target Hela cells and displayed dose-dependent antitumor effect. In vivo experiments demonstrated that [¹³¹I]I-RT-H₂ obviously inhibited the tumor proliferation in HeLa tumor-bearing mice within 4 weeks. All these results indicate that RT-H₂ has the potential to serve as a multifunctional platform for tumor diagnosis and treatment.

New Composite Contrast Agents Based on Ln and Graphene Matrix for Multi-Energy Computed Tomography

The subject of the current research study is aimed at the development of novel types of contrast agents (CAs) for multi-energy computed tomography (CT) based on Ln-graphene composites, which include Ln (Ln = La, Nd, and Gd) nanoparticles with a size of 2-3 nm, acting as key contrasting elements, and graphene nanoflakes (GNFs) acting as the matrix. The synthesis and surface modifications of the GNFs and the properties of the new CAs are presented herein. The samples have had their characteristics determined using X-ray photoelectron spectroscopy, X-Ray diffraction, transmission electron microscopy, thermogravimetric analysis, and Raman spectroscopy. Multi-energy CT images of the La-, Nd-, and Gd-based CAs demonstrating their visualization and discriminative properties, as well as the possibility of a quantitative analysis, are presented.

Functionalized Mesoporous Silica as Doxorubicin Carriers and Cytotoxicity Boosters

Mesoporous silica nanoparticles (MSNs) bearing methyl, thiol or glucose groups were synthesized, and their encapsulation and release behaviors for the anticancer drug Doxorubicin (Dox) were investigated in comparison with nonporous homologous materials. The chemical modification of thiol-functional silica with a double bond glucoside was completed for the first time, by green thiol-ene photoaddition. The MSNs were characterized in terms of structure (FT-IR, Raman), morphology (TEM), porosity (nitrogen sorption–desorption) and Zeta potential measurements. The physical interactions responsible for the Dox encapsulation were investigated by analytic methods and MD simulations, and were correlated with the high loading efficiency of MSNs with thiol and glucose groups. High release at pH 5 was observed in most cases, with thiol-MSN exhibiting 98.25% cumulative release in sustained profile. At pH 7.4, the glucose-MSN showed 75.4% cumulative release, while the methyl-MSN exhibited a sustained release trend. The in vitro cytotoxicity was evaluated on NDHF, MeWo and HeLa cell lines by CellTiter-Glo assay, revealing strong cytotoxic effects in all of the loaded silica at low equivalent Dox concentration and selectivity for cancer cells. Atypical applications of each MSN as intravaginal, topical or oral Dox administration route could be proposed.

Gene-Directed Enzyme Prodrug Therapy by Dendrimer-Like Mesoporous Silica Nanoparticles against Tumor Cells

We report herein a gene-directed enzyme prodrug therapy (GDEPT) system using gated mesoporous silica nanoparticles (MSNs) in an attempt to combine the reduction of side effects characteristic of GDEPT with improved pharmacokinetics promoted by gated MSNs. The system consists of the transfection of cancer cells with a plasmid controlled by the cytomegalovirus promoter, which promotes β-galactosidase (β-gal) expression from the bacterial gene lacZ (CMV-lacZ). Moreover, dendrimer-like mesoporous silica nanoparticles (DMSNs) are loaded with the prodrug doxorubicin modified with a galactose unit through a self-immolative group (DOXO-Gal) and modified with a disulfide-containing polyethyleneglycol gatekeeper. Once in tumor cells, the reducing environment induces disulfide bond rupture in the gatekeeper with the subsequent DOXO-Gal delivery, which is enzymatically converted by β-gal into the cytotoxic doxorubicin drug, causing cell death. The combined treatment of the pair enzyme/DMSNs-prodrug are more effective in killing cells than the free prodrug DOXO-Gal alone in cells transfected with β-gal.

pH/Thermo-Responsive Grafted Alginate-Based SiO2 Hybrid Nanocarrier/Hydrogel Drug Delivery Systems

We report the preparation of mesoporous silica nanoparticles covered by layer by layer (LbL) oppositely charged weak polyelectrolytes, comprising poly(allylamine hydrochloride) (PAH) and a sodium alginate, highly grafted by N-isopropylacrylamide/N-tert-butylacrylamide random copolymers, NaALG-g-P(NIPAM90-co-NtBAM10) (NaALG-g). Thanks to the pH dependence of the degree of ionization of the polyelectrolytes and the LCST-type thermosensitivity of the grafting chains of the NaALG-g, the as-prepared hybrid nanoparticles (hNP) exhibit pH/thermo-responsive drug delivery capabilities. The release kinetics of rhodamine B (RB, model drug) can be controlled by the number of PAH/NaALG-g bilayers and more importantly by the environmental conditions, namely, pH and temperature. As observed, the increase of pH and/or temperature accelerates the RB release under sink conditions. The same NaALG-g was used as gelator to fabricate a hNP@NaALG-g hydrogel composite. This formulation forms a viscous solution at room temperature, and it is transformed to a self-assembling hydrogel (sol-gel transition) upon heating at physiological temperature provided that its Tgel was regulated at 30.7 °C, by the NtBAM hydrophobic monomer incorporation in the side chains. It exhibits excellent injectability thanks to its combined thermo- and shear-responsiveness. The hNP@NaALG-g hydrogel composite, encapsulating hNP covered with one bilayer, exhibited pH-responsive sustainable drug delivery. The presented highly tunable drug delivery system (DDS) (hNP and/or composite hydrogel) might be useful for biomedical potential applications.

Amino Functionalized Micro-Mesoporous Hybrid Particles for the Sustained Release of the Antiretroviral Drug Tenofovir

The sustained release of an antiretroviral agent to women mucosa has been proved as an excellent strategy to reduce the sexual transmission of HIV. Hybrid micro-mesoporous particles have been synthesized and functionalized with a silane coupling agent followed by loading the antiretroviral tenofovir. It has been observed that the disposition of the silane molecule on the surface of the particles determines the interaction mechanism with the antiretroviral molecule loaded independently on the surface area of the particles. In this sense, available and free amino groups are required to achieve a smart pH-responsive material, a condition that is only achieved in those materials containing a silane chemisorbed monolayer. Moreover, the modulation of the release kinetics attributed to the presence of the silane monolayer covering the mesopores has been confirmed by fitting the releasing curves to the first order and Weibull models. The developed micro-mesoporous particles have been demonstrated to be excellent smart-release vehicles for antiviral agents and can be safely used in polymer mucoadhesive vaginal gels.

A brief review on solid lipid nanoparticles: part and parcel of contemporary drug delivery systems

Drug delivery technology has a wide spectrum, which is continuously being upgraded at a stupendous speed. Different fabricated nanoparticles and drugs possessing low solubility and poor pharmacokinetic profiles are the two major substances extensively delivered to target sites. Among the colloidal carriers, nanolipid dispersions (liposomes, deformable liposomes, virosomes, ethosomes, and solid lipid nanoparticles) are ideal delivery systems with the advantages of biodegradation and nontoxicity. Among them, nano-structured lipid carriers and solid lipid nanoparticles (SLNs) are dominant, which can be modified to exhibit various advantages, compared to liposomes and polymeric nanoparticles. Nano-structured lipid carriers and SLNs are non-biotoxic since they are biodegradable. Besides, they are highly stable. Their (nano-structured lipid carriers and SLNs) morphology, structural characteristics, ingredients used for preparation, techniques for their production, and characterization using various methods are discussed in this review. Also, although nano-structured lipid carriers and SLNs are based on lipids and surfactants, the effect of these two matrixes to build excipients is also discussed together with their pharmacological significance with novel theranostic approaches, stability and storage.

Multimodal Decorations of Mesoporous Silica Nanoparticles for Improved Cancer Therapy

The presence of leaky vasculature and the lack of lymphatic drainage of small structures by the solid tumors formulate nanoparticles as promising delivery vehicles in cancer therapy. In particular, among various nanoparticles, the mesoporous silica nanoparticles (MSN) exhibit numerous outstanding features, including mechanical thermal and chemical stability, huge surface area and ordered porous interior to store different anti-cancer therapeutics with high loading capacity and tunable release mechanisms. Furthermore, one can easily decorate the surface of MSN by attaching ligands for active targeting specifically to the cancer region exploiting overexpressed receptors. The controlled release of drugs to the disease site without any leakage to healthy tissues can be achieved by employing environment responsive gatekeepers for the end-capping of MSN. To achieve precise cancer chemotherapy, the most desired delivery system should possess high loading efficiency, site-specificity and capacity of controlled release. In this review we will focus on multimodal decorations of MSN, which is the most demanding ongoing approach related to MSN application in cancer therapy. Herein, we will report about the recently tried efforts for multimodal modifications of MSN, exploiting both the active targeting and stimuli responsive behavior simultaneously, along with individual targeted delivery and stimuli responsive cancer therapy using MSN.

Fate of GdF3 nanoparticles-loaded PEGylated carbon capsules inside mice model: a step toward clinical application

The successful translation of nanostructure-based bioimaging and/or drug delivery system needs extensive in vitro and in vivo studies on biocompatibility, biodistribution, clearance, and toxicity for its diagnostic applications. Herein, we have investigated the in vitro cyto-hemocompatibility, in vivo biodistribution, clearance, and toxicity in mice after systemic administration of GdF₃ nanoparticles loaded PEGylated mesoporous carbon capsule (GdF₃-PMCC)-based theranostic system. In vitro cyto-hemocompatibility study showed a very good biocompatibility up to concentration of 500 µg/ml. Biodistribution studies carried out from 1 h to 8 days showed that GdF₃-PMCC was found in major organs, such as liver, kidney, spleen, and muscle till 4th day and it was negligible in any tissue after 8th day. The clearance study was carried out for a period of 8 days and it was observed that the urinary system is the main route of excretion of GdF₃-PMCC. The tissue toxicity study was done for 15 days and histopathological analysis indicated that the GdF₃-PMCC based theranostic system does not have any adverse effect in tissues. Thus, PMCCs are nontoxic and can be applied as theranostic agents in contrast to the other carbon-based systems (PEGylated carbon nanotubes and PEGylated graphene oxide) which showed significant toxicity.

Multicompartmental Mesoporous Silica/Polymer Nanostructured Hybrids: Design Capabilities by Integrating Linear and Star-Shaped Block Copolymers

Poly(2-vinyl pyridine)-b-poly(ethylene oxide) (P2VP-b-PEO) linear diblock copolymer and polystyrene-poly(ethylene oxide) (PS10PEO10) heteroarm star copolymer were used as building elements to prepare organic-inorganic hybrids. By using the layer-by-layer (LbL) methodology, these elements were integrated on mesoporous silica through non-covalent interactions, namely, ionic and H-bonding. For the latter, tannic acid (TA) was used as an intermediate layer. The deposition of the various layers was monitored by thermogravimetric analysis (TGA), electrophoretic measurements, and confocal microscopy. The final silica hybrid, bearing alternating P2VP-b-PEO and PS10PEO10 star layers was capable of carrying one hydrophilic and two hydrophobic chemical species in distinct compartments. These multicompartmental organic-inorganic hybrids could be used as nanostructured carriers for pH-responsive multiple drug delivery and potential theranostic applications.

Recent developments in the use of organic-inorganic nanohybrids for drug delivery

Organic-inorganic nanohybrid (OINH) structures providing a versatile platform for drug delivery with improved characteristics are an area which has gained recent attention. Much effort has been taken to develop these structures to provide a viable treatment options for much alarming diseases such as cancer, bone destruction, neurological disorders, and so on. This review focuses on current work carried out in producing different types of hybrid drug carriers identifying their properties, fabrication techniques, and areas where they have been applied. A brief introduction on understating the requirement for blending organic-inorganic components into a nanohybrid drug carrier is followed with an elaboration given about the different types of OINHs developed currently highlighting their properties and applications. Then, different fabrication techniques are discussed given attention to surface functionalization, one-pot synthesis, wrapping, and electrospinning methods. Finally, it is concluded by briefing the challenges that are remaining to be addressed to obtain multipurpose nanohybrid drug carriers with wider applicability. This article is categorized under: Therapeutic Approaches and Drug Discovery > Emerging Technologies.

Theranostic Nanomedicine for Malignant Gliomas

Brain tumors mainly originate from glial cells and are classified as gliomas. Malignant gliomas represent an incurable disease; indeed, after surgery and chemotherapy, recurrence appears within a few months, and mortality has remained high in the last decades. This is mainly due to the heterogeneity of malignant gliomas, indicating that a single therapy is not effective for all patients. In this regard, the advent of theranostic nanomedicine, a combination of imaging and therapeutic agents, represents a strategic tool for the management of malignant brain tumors, allowing for the detection of therapies that are specific to the single patient and avoiding overdosing the non-responders. Here, recent theranostic nanomedicine approaches for glioma therapy are described.

Comparison of Polydopamine-Coated Mesoporous Silica Nanorods and Spheres for the Delivery of Hydrophilic and Hydrophobic Anticancer Drugs

Mesoporous silica nanoparticles (MSNs) have been widely studied as drug delivery systems in nanomedicine. Surface coating of MSNs have enabled them to perform efficiently in terms of bioavailability, biocompatibility, therapeutic efficacy and targeting capability. Recent studies have suggested the use of polydopamine (PDA) as a facilitative coating for MSNs that provides sustained and pH-responsive drug release, owing to the adhesive "molecular-glue" function of PDA. This further endows these hybrid MSN@PDA particles with the ability to carry large amounts of hydrophilic drugs. In this study, we expand the feasibility of this platform in terms of exploring its ability to also deliver hydrophobic drugs, as well as investigate the effect of particle shape on intracellular delivery of both a hydrophilic and hydrophobic anticancer drug. MSN@PDA loaded with doxorubicin (hydrophilic) and fingolimod (hydrophobic) was studied via a systematic in vitro approach (cellular internalization, intracellular drug distribution and cytotoxicity). To promote the cellular uptake of the MSN@PDA particles, they were further coated with a polyethylene imine (PEI)-polyethylene glycol (PEG) copolymer. Drug-loaded, copolymer-coated MSN@PDA showed effective cellular uptake, intracellular release and an amplified cytotoxic effect with both doxorubicin and fingolimod. Additionally, rods exhibited delayed intracellular drug release and superior intracellular uptake compared to spheres. Hence, the study provides an example of how the choice and design of drug delivery systems can be tuned by the need for performance, and confirms the PDA coating of MSNs as a useful drug delivery platform beyond hydrophilic drugs.

Large Pore Mesoporous Silica and Organosilica Nanoparticles for Pepstatin A Delivery in Breast Cancer Cells

(1) Background: Nanomedicine has recently emerged as a new area of research, particularly to fight cancer. In this field, we were interested in the vectorization of pepstatin A, a peptide which does not cross cell membranes, but which is a potent inhibitor of cathepsin D, an aspartic protease particularly overexpressed in breast cancer. (2) Methods: We studied two kinds of nanoparticles. For pepstatin A delivery, mesoporous silica nanoparticles with large pores (LPMSNs) and hollow organosilica nanoparticles (HOSNPs) obtained through the sol⁻gel procedure were used. The nanoparticles were loaded with pepstatin A, and then the nanoparticles were incubated with cancer cells. (3) Results: LPMSNs were monodisperse with 100 nm diameter. HOSNPs were more polydisperse with diameters below 100 nm. Good loading capacities were obtained for both types of nanoparticles. The nanoparticles were endocytosed in cancer cells, and HOSNPs led to the best results for cancer cell killing. (4) Conclusions: Mesoporous silica-based nanoparticles with large pores or cavities are promising for nanomedicine applications with peptides.

Highly Stable and NIR Luminescent Ru-LPMSN Hybrid Materials for Sensitive Detection of Cu2+ in Vivo

Herein, new near-infrared (NIR) luminescent ruthenium complexes were prepared for detecting Cu²⁺ ions. Then, ruthenium complex hybrid nanomaterials (Ru-LPMSNs) were fabricated successfully by imbedding the ruthenium complex into mesoporous silica nanoparticles. Benefiting from the novel large-pore mesoporous structure and good adsorbility of LPMSNs, Ru-LPMSN hybrid materials showed a significantly enhanced fluorescence intensity and stability. NIR fluorescence of Ru-LPMSNs was rapidly quenched by Cu²⁺ ions. Ru-LPMSNs also showed high Cu²⁺ ion selectivity and sensitivity as a sensor. The detection limit of Cu²⁺ ions was 10 nM with a wide linear relationship between the fluorescence intensity of Ru-LPMSNs and the concentration of Cu²⁺ ions. The mechanism of fluorescence quenching might be that the combination of the ruthenium complex and Cu²⁺ ions constrained the photoinduced electron-transfer process. Furthermore, Ru-LPMSNs dramatically increased the fluorescence signals in cells and achieved Cu²⁺-ion detection. Ru-LPMSNs had different tissue affinities and could monitor distribution of exogenous Cu²⁺ ions in vivo. Moreover, Ru-LPMSNs realized direct and rapid detection of Cu²⁺-ion content in serum. These results indicated the potential applications of the prepared nanomaterials as Cu²⁺ detection agents.

Highly efficient triazolone/metal ion/polydopamine/MCM-41 sustained release system with pH sensitivity for pesticide delivery

MCM-41 was prepared through the sol-gel method and encapsulated by polydopamine (PDA) before being coordinated with metal ions to form a highly efficient sustained release system (M-PDA-MCM-41) for triazolone delivery. The characterization results confirmed the existence of the coordination bond between the PDA layer and triazolone through the bridge effect from metal ions, which enhanced the interaction between PDA-MCM-41 and triazolone. The adsorption capacity of Fe-PDA-MCM-41 increased up to 173 mg g-1, which was 160% more than that of MCM-41. The sustained release performance of M-PDA-MCM-41 in different pH values was investigated. Under the conditions of pH ≤7, the release speed of triazolone increased with pH decreasing, whereas its release speed in the weak base condition was slower than in the neutral condition. Therefore, the as-synthesized system showed significant pH-sensitivity in the sustained release process, indicating that the sustained release system can be well stored in the neutral or basic environment and activated in the acid environment. Their sustained release curves described by the Korsmeyer-Peppas equation at pH 7 showed the same behaviour, indicating that PDA decoration or metal ion coordination only increases the steric hindrance and the interaction between carrier and triazolone instead of changing the original structure of the pure MCM material in accordance with X-ray diffraction and Brunauer-Emmett-Teller analysis results.

Progress in Nanotheranostics Based on Mesoporous Silica Nanomaterial Platforms

Theranostics based on nanoparticles (NPs) is a promising paradigm in nanomedicine. Mesoporous silica nanoparticle (MSN)-based systems offer unique characteristics to enable multimodal imaging or simultaneous diagnosis and therapy. They include large surface area and volume, tunable pore size, functionalizable surface, and acceptable biological safety. Hybridization with other NPs and chemical modification can further potentiate the multifunctionality of MSN-based systems toward translation. Here, we update the recent progress on MSN-based systems for theranostic purposes. We discuss various synthetic approaches used to construct the theranostic platforms either via intrinsic chemistry or extrinsic combination. These include defect generation in the silica structure, encapsulation of diagnostic NPs within silica, their assembly on the silica surface, and direct conjugation of dye chemicals. Collectively, in vitro and in vivo results demonstrate that multimodal imaging capacities can be integrated with the therapeutic functions of these MSN systems for therapy. With further improvement in bioimaging sensitivity and targeting specificity, the multifunctional MSN-based theranostic systems will find many clinical applications in the near future.

Optimized Rhodamine B labeled mesoporous silica nanoparticles as fluorescent scaffolds for the immobilization of photosensitizers: a theranostic platform for optical imaging and photodynamic therapy

A highly efficient bifunctional mesoporous silica nanodevice coupling optical imaging with photodynamic therapy (PDT) was successfully prepared by using Rhodamine B as a contrast agent and verteporfin as a photosensitizer. The precise localization and high dispersion of the contrast agent in the nanoparticles is the key point to get higher fluorescence quantum yields with respect to the fluorophore in solution. To obtain this information photoluminescence spectroscopy coupled with fluorescence lifetime measurements was used, due to its high sensitivity. The bifunctional nanodevice showed good performances both in terms of quantum yield of the anchored Rhodamine B (Φ(RhB) = 0.55) and the singlet oxygen delivery efficiency for PDT applications.

Facile synthesis of a highly water-soluble graphene conjugated chlorophyll-a photosensitizer composite for improved photodynamic therapy in vitro

Graphene conjugated withp-bromo-phenylhydrazone-methyl pyropheophorbide-a (BPMppa, 683 nm), which is derived from a chlorophyll-aphotosensitizer, shows significantly improved water-solubility and PDT efficiency.

In vitro and in vivo assessment of EDTA-modified silica nano-spheres with supreme capacity of iron capture as a novel antidote agent

Mesoporous silica nanoparticles having structure of MCM-41 category with amine and EDTA functional groups in the pores were prepared using a co-condensation reaction. The synthetic steps eventuated in the mesoporous silica nanoparticles with spherical sizes lower than 50nm supposed to have high surface area. The nanoparticles' structure and functionality were characterized by FTIR spectroscopy and CHN analysis and the topography were examined by SEM and TEM and hydrodynamic sizes were demonstrated by DLS. The crystallinity and mesoporous pattern were figured out by XRD technique. Then the efficiency of these materials was tested in vitro and in vivo in adsorbing ferrous sulfate which is a supplement normally prescribed in treating iron deficiency and its overdose is potentially lethal, especially in young children. In vivo experiments illustrated that both nanoparticles could efficiently be administrated as an antidote agent against iron overdose, but EDTA-MSN nanoparticles were superior to NH₂-MSN nanoparticles.

Multifunctional Gold-Mesoporous Silica Nanocomposites for Enhanced Two-Photon Imaging and Therapy of Cancer Cells

Three dimensional sub-micron resolution has made two-photon nanomedicine a very promising medical tool for cancer treatment since current techniques cause significant side effects for lack of spatial selectivity. Two-photon-excited (TPE) photodynamic therapy (PDT) has been achieved via mesoporous nanoscaffolds, but the efficiency of the treatment could still be improved. Herein, we demonstrate the enhancement of the treatment efficiency via gold-mesoporous organosilica nanocomposites for TPE-PDT in cancer cells when compared to mesoporous organosilica particles. We performed the first comparative study of the influence of the shape and spatial position of gold nanoparticles (AuNPs) with mesoporous silica nanoparticles (MSN) functionalized with thiol groups and doped with a two-photon electron donor (2PS). The resulting multifunctional nanocarriers displayed TPE-fluorescence and were imaged inside cells. Furthermore, mesoporous organosilica NPs decorated gold nanospheres (AuNSs) induced 63 percent of selective killing on MCF-7 breast cancer cells. This study thus provides insights for the design of more effective multifunctional two-photon-sensitive nanocomposites via AuNPs for biomedical applications.

Hierarchical mesoporous silicas templated by PE-b-PEO-b-PLA triblock copolymer for fluorescent drug delivery

Hierarchical mesoporous silicas for fluorescent drug-delivery molecule templated by PE-b-PEO-b-PLA triblock copolymer.

Highly efficient alginate sodium encapsulated chlorpyrifos/copper(ii) Schiff base mesoporous silica sustained release system with pH and ion response for pesticide delivery

A highly efficient sustained released system (ALG–CH–Cu–MCM-41) was prepared. The as-synthesized system showed significant pH and ion responsive.

Hybrid Nanomaterials Based on Iron Oxide Nanoparticles and Mesoporous Silica Nanoparticles: Overcoming Challenges in Current Cancer Treatments

The current approaches used for the treatment of cancer face some clinical limitations such as induction of severe side effects, multidrug resistance (MDR), and low specificity toward metastatic cancer cells. Hybrid nanomaterials hold a great potential to overcome all these challenges. Among hybrid nanoparticles, those based on mesoporous silica and iron oxide nanoparticles (MSNs and IONPs) have gained a privileged place in the biomedical field because of their outstanding properties. There are many studies demonstrating their effectiveness as drug delivery systems, nanoheaters, and imaging contrast agents. This review summarizes the advances related to the utilization of IONPs and MSNs for reducing side effects, overcoming MDR, and inhibiting metastasis. Furthermore, we give a future perspective of the clinical application of these technologies.

Pharmacokinetics, pharmacodynamics and toxicology of theranostic nanoparticles

Nanoparticles (NPs) are considered a promising tool in both diagnosis and therapeutics. Theranostic NPs possess the combined properties of targeted imaging and drug delivery within a single entity. While the categorization of theranostic NPs is based on their structure and composition, the pharmacokinetics of NPs are significantly influenced by the physicochemical properties of theranostic NPs as well as the routes of administration. Consequently, altered pharmacokinetics modify the pharmacodynamic efficacy and toxicity of NPs. Although theranostic NPs hold great promise in nanomedicine and biomedical applications, a lack of understanding persists on the mechanisms of the biodistribution and adverse effects of NPs. To better understand the diagnostic and therapeutic functions of NPs, this review discusses the factors that influence the pharmacokinetics, pharmacodynamics and toxicology of theranostic NPs, along with several strategies for developing novel diagnostic and therapeutic modalities.

Catalytic mesoporous Janus nanomotors for active cargo delivery

We report on the synergy between catalytic propulsion and mesoporous silica nanoparticles (MSNPs) for the design of Janus nanomotors as active cargo delivery systems with sizes <100 nm (40, 65, and 90 nm). The Janus asymmetry of the nanomotors is given by electron beam (e-beam) deposition of a very thin platinum (2 nm) layer on MSNPs. The chemically powered Janus nanomotors present active diffusion at low H2O2 fuel concentration (i.e., <3 wt %). Their apparent diffusion coefficient is enhanced up to 100% compared to their Brownian motion. Due to their mesoporous architecture and small dimensions, they can load cargo molecules in large quantity and serve as active nanocarriers for directed cargo delivery on a chip.

Core-shell-type magnetic mesoporous silica nanocomposites for bioimaging and therapeutic agent delivery

Advances in nanotechnology and nanomedicine offer great opportunities for the development of nanoscaled theranostic platforms. Among various multifunctional nanocarriers, magnetic mesoporous silica nanocomposites (M-MSNs) attract prominent research interest for their outstanding properties and potential biomedical applications. This Research News article highlights recent progress in the design of core-shell-type M-MSNs for both diagnostic and therapeutic applications. First, an overview of synthetic strategies for three representative core-shell-type M-MSNs with different morphologies and structures is presented. Then, the diagnostic functions of M-MSNs is illustrated for magnetic resonance imaging (MRI) applications. Next, magnetic targeted delivery and stimuli-responsive release of drugs, and effective package of DNA/siRNA inside mesopores using M-MSNs as therapeutic agent carriers are discussed. The article concludes with some important challenges that need to be overcome for further practical applications of M-MSNs in nanomedicine.

Thermoresponsive gold nanoshell@mesoporous silica nano-assemblies: an XPS/NMR survey

An XPS/NMR survey of the step by step assembly of functional Au@SiO₂ nanoshells for use in nanomedicine.

Haemolytic activity and cellular toxicity of SBA-15-type silicas: elucidating the role of the mesostructure, surface functionality and linker length

Haemolytic activity and cellular toxicity of native, amino-, mercapto-, and carboxy-terminated SBA-15-type silicates were investigated.

Biocompatible SiO2in the Fabrication of Stimuli-Responsive Hybrid Composites and Their Application Potential

Organic/inorganic hybrid composite materials have been extensively studied as they combine the properties of inorganic material and organic polymer. Among the inorganic material biocompatible silica (SiO2) is an interesting candidate for application in biotechnology because such material is wide spread in nature as well as in medicine. During the last few decades, stimuli-responsive polymers are drawing much attention from the researchers for application versatility such as target-specific delivery of drug and corrosion inhibitors. Considering the biocompatibility and many such important properties as high cargo loading capacity, long blood circulation lifetime, enhanced permeability and retention, mechanical strength, and easy processability, combination of SiO2particles with stimuli-responsive polymers is gaining attention over the last decade. This review article will report the progress made towards the development and application of stimuli-responsive hybrid composites based on SiO2.

Silica-based nanoparticles: a versatile tool for the development of efficient imaging agents

In this review a selection of the most recent examples of imaging techniques applied to silica-based NPs for imaging is reported.

Size-dependent physicochemical properties of mesoporous nanosilica produced from natural quartz sand using three different methods

Mesoporous high-surface-area silica (SiO₂) nanoparticles were produced from natural quartz sand (orthoquartzite) using three processing methods namely sol–gel, sonication, and spray pyrolysis.

Effect of pH-responsive alginate/chitosan multilayers coating on delivery efficiency, cellular uptake and biodistribution of mesoporous silica nanoparticles based nanocarriers

Surface fuctionalization plays a crucial role in developing efficient nanoparticulate drug-delivery systems by improving their therapeutic efficacy and minimizing adverse effects. Here we propose a simple layer-by-layer self-assembly technique capable of constructing mesoporous silica nanoparticles (MSNs) into a pH-responsive drug delivery system with enhanced efficacy and biocompatibility. In this system, biocompatible polyelectrolyte multilayers of alginate/chitosan were assembled on MSN's surface to achieve pH-responsive nanocarriers. The functionalized MSNs exhibited improved blood compatibility over the bare MSNs in terms of low hemolytic and cytotoxic activity against human red blood cells. As a proof-of-concept, the anticancer drug doxorubicin (DOX) was loaded into nanocarriers to evaluate their use for the pH-responsive drug release both in vitro and in vivo. The DOX release from nanocarriers was pH dependent, and the release rate was much faster at lower pH than that of at higher pH. The in vitro evaluation on HeLa cells showed that the DOX-loaded nanocarriers provided a sustained intracellular DOX release and a prolonged DOX accumulation in the nucleus, thus resulting in a prolonged therapeutic efficacy. In addition, the pharmacokinetic and biodistribution studies in healthy rats showed that DOX-loaded nanocarriers had longer systemic circulation time and slower plasma elimination rate than free DOX. The histological results also revealed that the nanocarriers had good tissue compatibility. Thus, the biocompatible multilayers functionalized MSNs hold the substantial potential to be further developed as effective and safe drug-delivery carriers.

Recent development of silica nanoparticles as delivery vectors for cancer imaging and therapy

In spite of significant advances in early detection and combined treatments, a number of cancers are often diagnosed at advanced stages and thereby carry a poor prognosis. Developing novel prognostic biomarkers and targeted therapies may offer alternatives for cancer diagnosis and treatment. Recent rapid development of nanomaterials, such as silica based nanoparticles (SiNPs), can just render such a promise. In this article, we attempt to summarize the recent progress of SiNPs in tumor research as a novel delivery vector. SiNP-assisted imaging techniques are used in cancer diagnosis both in vitro and in vivo. Meanwhile, SiNP-mediated drug delivery can efficiently treat tumor by carrying chemotherapeutic agents, photosensitizers, photothermal agents, siRNA, and gene therapeutic agents. Finally, SiNPs that contain at least two different functional agents may be more powerful for both tumor imaging and therapy.

FROM THE CLINICAL EDITOR

This paper summarizes recent progress on the field of silica nanoparticles research as novel delivery vectors for cancer-specific imaging as well as drug delivery of chemotherapeutics, photosensitizers, photothermal agents, siRNA, and gene therapy agents.

Redox responsive Pd(ii) templated rotaxane nanovalve capped mesoporous silica nanoparticles: a folic acid mediated biocompatible cancer-targeted drug delivery system

Herein, redox responsive Pd(ii) templated rotaxane nanovalve capped mesoporous silica nanoparticles were designed for an effective cancer-targeted drug delivering system.

Redox-responsive nanoreservoirs based on collagen end-capped mesoporous hydroxyapatite nanoparticles for targeted drug delivery

Schematic illustration of a redox-responsive system based on collagen-capped MHAp for cell-targeted drug delivery.