Mesoporous inorganic nanoscale particles for drug adsorption and controlled release

Influence of natural polysaccharides on the morphology and properties of hybrid vaterite microcrystals

Co-precipitation of biopolymers into calcium carbonate crystals changes their physicochemical and biological properties. This work studies hybrid microcrystals of vaterite obtained in the presence of natural polysaccharides, as carriers for the delivery of proteins and enzymes. Hybrid microcrystals with dextran sulfate, chondroitin sulfate, heparin, fucoidan, and pectin were obtained and compared. The impact of polysaccharides on the morphology (particle diameter, surface area, nanocrystallite and pore size), polysaccharide content and surface charge of hybrid microcrystals was studied. Only microcrystals with fucoidan and heparin exhibited antioxidant activity against •ОН radical. The surface charge and pore size of the hybrid microcrystals affected the sorption of albumin, catalase, chymotrypsin, mucin. A decrease in the catalytic constant and Michaelis constant was observed for catalase sorbed on the hybrid crystals. The biocompatibility of microcrystals depended on the nature of the included polysaccharide: crystals with sulfated polysaccharides increased blood plasma coagulation but not platelet aggregation, and crystals with dextran sulfate had the greatest cytotoxicity against HT-29 cells but not erythrocytes. Hybrid microcrystals with all polysaccharides except chondroitin sulfate reduced erythrocyte lysis in vitro compared with vaterite crystals. The obtained results enable to create novel carriers based on hybrid vaterite crystals with polysaccharides, beneficial for the delivery of protein drugs.

Synergistic Sustained Drug-Release System Based on Immobilized Rhamnus frangula L. Phytoextract into Layered Double Hydroxide Covered by Biocompatible Hydrogel

This work focuses on the synergetic effect obtained by immobilization of Rhamnus frangula L. (RfL) phytoextract in layered double hydroxides (LDHs) matrixes and their subsequent encapsulation into biocompatible hydrogels (HG). In this respect, the LDHs were used as hosts for the immobilization of the phytoextract by a reconstruction method, after which the LDHsRfL were embedded into biocompatible hydrogel (HG) matrixes, based on polyethylene glycol diacrylate (PEGDA), by a radical polymerization reaction. The resulted biocompatible hydrogel composites were characterized by modern methods, while the swelling and rheology measurements revealed that the HG composites steadily improved as the content of RfL phytoextract immobilized on LDHs (LDHsRfL) increased. The following in vitro sustained release of the RfL phytoextract was highlighted by measurements at pH 6.8, in which case the composite HGs with LDHsRfL presented an improved release behavior over the LDHsRfL, thus, underlining the synergistic effect of PEGDA network and LDH particles on the slow-release behavior. The kinetic models used in the RfL release from composite HGs clearly indicate that the release is diffusion controlled in all the cases. The final composite HGs described here may find applications in the pharmaceutical field as devices for the controlled release of drugs.

Calcium carbonate vaterite particles for drug delivery: Advances and challenges

The recent successful application of lipid-based nanoparticles as delivery vehicles in COVID-19 vaccines demonstrated the superior potential of nanoparticle-based technology for targeted drug delivery in biomedicine. Among novel, rapidly advancing delivery platforms, the inorganic nano/microparticles gradually reach new heights and attract well-deserved attention among scientists and clinicians. Calcium carbonate in its vaterite form is used as a biocompatible carrier for a progressively increasing number of biomedical applications. Its growing popularity is conferred by beneficial porosity of particles, high mechanical stability, biodegradability under certain physiological conditions, ability to provide a continuous steady release of bioactives, preferential safety profile, and low cost, which make calcium carbonate a suitable entity of highly efficacious formulations for controlled drug delivery and release. The focal point of the current review is the success of the recent vaterite applications in the delivery of various diagnostics and therapeutic drugs. The manuscript highlights the nuances of drug loading in vaterite particles, connecting it with particle morphology, size, and charge of the loaded molecules, payload concentration, mono- or multiple drug loading. The manuscript also depicts recent successful methods of increasing the loading capacity developed for vaterite carriers. In addition, the review describes the various administration routes for vaterite particles with bioactive payloads, which were reported in recent years. Special attention is given to the multi-drug-loaded vaterite particles ("molecular cocktails") and reports on their successful delivery in vitro and in vivo.

Sepiolite Nanocarriers as a Matrix for Controlled Thermal Energy Storage

Applying the eutectic hydrated salt (EHS) mixture of Na2HPO4·12H2O and Na2SO4·10H2O in a 1:1 weight ratio as a phase-change material and natural sepiolite nanocarriers as a matrix, the form-stable phase-change composite EHS@sepiolite was fabricated by vacuum impregnation. Due to the high porosity of sepiolite and its nanofibrous structure with internal channels, the effective loading of the phase-change material reached as high as 88 wt %. The melting temperature of the composite was 38.1 °C and its melting enthalpy was 185 J g-1. The crystallinity of the hydrated salt mixture was retained after loading into the sepiolite matrix. The composite demonstrated high stability over 50 heat uptake/release cycles maintaining its melting temperature and melting enthalpy the same. The combination of natural sepiolite nanocarriers and crystallohydrates is a cheap and efficient nanoscale energy storage system with high potential for practical applications and upscaling because of their natural abundance.

Smart Polymeric Nanoparticles with pH-Responsive and PEG-Detachable Properties (II): Co-Delivery of Paclitaxel and VEGF siRNA for Synergistic Breast Cancer Therapy in Mice

Background

The dual-loaded nano-delivery system can realize chemotherapeutic drug and small interfering RNA (siRNA) co-loading as well as enhance the therapeutic effect of drugs on tumors through a synergistic effect, while reducing their toxic and side effects on normal tissues.

Methods

Previously, we developed layered smart nanoparticles (NPs) to co-deliver survivin siRNA as well as small molecule drugs for lung cancer. In this study, we used such smart NPs to co-deliver paclitaxel (PTX) and siRNA against vascular endothelial growth factor (VEGF) gene for breast cancer therapy in mice models. For the prepared NPs, characterizations such as particle size, zeta potential, gel electrophoresis imaging and in vitro stability were investigated. Then, 4T1 cells were used to evaluate the in vitro VEGF silencing capacity, tumor cell inhibitory and anti-apoptotic abilities. Finally, an orthotopic model of mouse breast cancer was established to evaluate the in vivo antitumor effects and safety properties of PTX-siRNA^VEGF-NPs.

Results

We prepared PTX-siRNA^VEGF-NPs with particle size of 85.25 nm, PDI of 0.261, and zeta potential of 5.25 mV. The NPs with VEGF siRNA effectively knocked down the expression of VEGF mRNA. Cell counting kit-8 (CCK-8) and apoptosis assays revealed that the PTX-siRNA^VEGF-NPs exhibited antiproliferation effect of PTX on 4T1 cells. The in vivo anti-tumor study indicated that PTX-siRNA^VEGF-NPs could exert an antitumor effect by inhibiting the formation and development of new blood vessels in tumor tissues, thereby cutting off nutrient and blood supplies required for tumor tissue growth. Both the anti-tumor efficacy and in vivo safety of the PTX-siRNA^VEGF-NPs group were better than that of the PTX-NPs and siRNA^VEGF-NPs groups.

Conclusion

The combination of PTX and VEGF siRNA exerts good antitumor effect on 4T1 tumor cells. This study provides a theoretical and practical basis for breast cancer therapy.

Clay nanoparticles as pharmaceutical carriers in drug delivery systems

INTRODUCTION

Clay minerals are a class of silicates with chemical inertness, colloid, and thixotropy, which have excellent physicochemical properties, good biocompatibility, low toxicity, and have high application potential in biomedical fields. These inorganic materials have been widely used in pharmaceutical excipients and active substances. In recent years, nanoclay mineral materials have been used as drug vehicles for the delivery of a variety of drugs based on their broad specific surface area, rich porosity, diverse morphology, good adsorption performance, and high ion exchange capacity.

AREAS COVERED

This review introduces the structures, properties, and applications of various common natural and synthetic nanoclay materials as drug carriers. Natural nanoclays have different morphologies including nanoplates, nanotubes, and nanofibers. Synthetic materials have controllable sizes and flexible structures, where mesoporous silica nanoparticles, laponite, and imogolite are typical ones. These inorganic nanoparticles are often linked to polymers to form multifunctional drug delivery systems for better pharmaceutical performance.

EXPERT OPINION

The clay nanomaterials have typical properties, including enhanced solubility of insoluble drugs, targeting therapeutic sites, controlled release, and stimulation of responsive drug delivery systems.

Cinnamaldehyde and Doxorubicin Co-Loaded Graphene Oxide Wrapped Mesoporous Silica Nanoparticles for Enhanced MCF-7 Cell Apoptosis

Background

Combined chemotherapy is often affected by the different physicochemical properties of chemotherapeutic drugs, which should be improved by the reasonable design of co-loaded preparations.

Purpose

A kind of simple but practical graphene oxide (GO) wrapped mesoporous silica nanoparticles (MSN) modified with hyaluronic acid (MSN@GO-HA) were developed for the co-delivery of cinnamaldehyde (CA) and doxorubicin (DOX), in order to enhance their combined treatment on tumor cells and reduce their application defects.

Methods

The MSN_CA@GO_DOX-HA was constructed by MSN_CA (loading CA via physical diffusion) and GO_DOX-HA (modified with HA and loading DOX via π–π stacking) through the electrostatic adsorption, followed by the physicochemical characterization, serum stability and in vitro release study. Cytotoxicity on different cells was detected, followed by the tumor cell uptake tests. The intracellular reactive oxygen species (ROS) changes, mitochondrial functions and activities of caspase-3/-9 in MCF-7 cells were also evaluated, respectively.

Results

The MSN_CA@GO_DOX-HA nanoparticles kept stable in FBS solution and achieved pH-responsive release behavior, which was beneficial to increase the accumulation of CA and DOX in tumor cells to enhance the treatment. MSN_CA@GO_DOX-HA exerted higher cytotoxicity to MCF-7 human breast cancer cells than H9c2 cardiac myocyte cells, which were not only attributed to the active targeting to tumor cells by HA, but also related with the activation of intrinsic apoptotic pathway in MCF-7 cells induced by CA, which was mediated by the specific ROS signal amplification and the interference with mitochondrial function. Moreover, the efficacy of DOX was also enhanced by the above process.

Conclusion

The establishment of the MSN_CA@GO_DOX-HA nanoparticles played a role in promoting strengths and restricting shortcomings of CA and DOX, thereby exerting their function and achieving efficient treatment against cancer.

Evaluation of Bone Gain and Complication Rates after Guided Bone Regeneration with Titanium Foils: A Systematic Review

Guided bone regeneration techniques are increasingly used to enable the subsequent placement of dental implants. This systematic review aims to analyze the success rate of these techniques in terms of bone gain and complications rate using titanium membranes as a barrier element. Electronic and hand searches were conducted in PubMed/Medline, Scielo, Scopus and Cochrane Library databases for case reports, case series, cohort studies and clinical trials in humans published up to and including 19 September 2020. Thirteen articles were included in the qualitative analysis. Bone gain both horizontally and vertically was comparable to that obtained with other types of membranes more commonly used. The postoperative complication rate was higher that of native collagen membranes and non-resorbable titanium-reinforced membranes, and similar that of crosslinked collagen membranes and titanium meshes. The survival rate of the implants was similar to that of implants placed in native bone. Due to the limited scientific literature published on this issue, more randomized clinical trials comparing occlusive titanium barriers and other types of membranes are necessary to reach more valid conclusions.

Formulation of Mesoporous Silica Nanoparticles for Controlled Release of Antimicrobials for Stone Preventive Conservation

The biotic deterioration of artifacts of archaeological and artistic interest mostly relies on the action of microorganisms capable of thriving under the most disparate environmental conditions. Thus, to attenuate biodeterioration phenomena, biocides can be used by the restorers to prevent or slow down the microbial growth. However, several factors such as biocide half-life, its wash-out because of environmental conditions, and its limited time of action make necessary its application repeatedly, leading to negative economic implications. Sound and successful treatments are represented by controlled release systems (CRSs) based on porous materials. Here, we report on the design and development of a CRS system based on mesoporous silica nanoparticles (MSNs), as a carrier, and loaded with a biocide. MSNs, with a diameter of 55 nm and cylindrical pores of ca. 3-8 nm arranged as parallel arrays concerning the NP diameter, and with 422 m²/g of specific surface area were synthesized by the sol-gel method assisted by oil in water emulsion. Biocide loading and release were carried out in water and monitored by UV-Vis Spectroscopy; in addition, microbiological assay was performed using as control the MCM-41 mesoporous silica loaded with the same biocide. The role of specific supramolecular interaction in regulating the release is discussed. Further, we demonstrated that this innovative formulation was useful in inhibiting the in vitro growth of Kocuria rhizophila, an environmental Gram-positive bacterial strain. Besides, the CRS here prepared reduced the bacterial biomass contaminating a real case study (i.e., stone derived from the Santa Margherita cave located in Sicily, Italy), after several months of treatment thus opening for innovative treatments of deteriorated stone artifacts.

Naturally derived nano- and micro-drug delivery vehicles: halloysite, vaterite and nanocellulose

We discuss prospects for halloysite nanotubes, vaterite crystals and nanocellulose to enter the market of biomaterials for drug delivery and tissue engineering, and their potential for economically viable production from abundant natural sources.

Ultrafast Synthesizing Bismuth Mesoporous Nanolitchi Radiosensitizer Loading High Dose DOX for CT-Guided Enhanced Chemoradiotherapy

Radiotherapy and chemotherapy are both common clinical treatment methods. The combination of the two treatments can decrease tumor recurrence. In this study, bismuth-based mesoporous litchi-shaped Na_0.2Bi_0.8O_0.35F_1.91:20%Yb (NBOF) nanoparticles (NPs) have been reported as a radiosensitizer and as a nanovehicle for loading and slow-releasing doxorubicin (DOX). After assembling with amphiphilic poly(ethylene glycol) (PEG), NBOF-DOX-PEG qualified with excellent aqueous dispersibility and the enhanced tumor radiation and chemo-synergistic therapy characteristics. The formation of NBOF revealed the oxygen element in NBOF came from H₂O and air in the synthesis and post-treatment process, and the size of NBOF could be adjusted by changing the concentration of doped Yb ion. The average size of NBOF was ca. 80 nm. Brunauer-Emmett-Teller results demonstrated the mesoporous structure of NBOF. So DOX could be loaded in NBOF and the optimized loading content was 39%. Then, NBOF-PEG exhibited a strong computed tomography signal whitening ability and enhanced radiotherapy effect. Combined with the chemotherapy ability of DOX, NBOF-DOX-PEG NPs presented remarkable synergistic tumor elimination ability. Meanwhile, NBOF-DOX-PEG NPs qualified for excellent biosafety. Our study not only proved the combined chemo- and radiotherapy for enhancing therapeutic effect but also supplied a functional Bi-based mesoporous nanovehicle for constructing an intelligent theranostic platform.

Nanocontainer-based self-healing coatings: current progress and future perspectives

Nanocontainers add more functionalities to the standard coating formulations.