Mesoporous Silica-Based Supports for the Controlled and Targeted Release of Bioactive Molecules in the Gastrointestinal Tract

The bioavailability, metabolism and microbial modulation of curcumin-loaded nanodelivery systems

Curcumin (Cur), the major bioactive component of turmeric (Curcuma longa) possesses many health benefits. However, low solubility, stability and bioavailability restricts its applications in food. Recently, nanocarriers such as complex coacervates, nanocapsules, liposomes, nanoparticles, nanomicelles, have been used as novel strategies to solve these problems. In this review, we have focused on the delivery systems responsive to the environmental stimuli such as pH-responsive, enzyme-responsive, targeted-to-specific cells or tissues, mucus-penetrating and mucoadhesive carriers. Besides, the metabolites and their biodistribution of Cur and Cur delivery systems are discussed. Most importantly, the interaction between Cur and their carriers with gut microbiota and their effects of modulating the gut health synergistically were discussed comprehensively. In the end, the biocompatibility of Cur delivery systems and the feasibility of their application in food industry is discussed. This review provided a comprehensive review of Cur nanodelivery systems, the health impacts of Cur nanocarriers and an insight into the application of Cur nanocarriers in food industry.

Nanoparticles loaded with pharmacologically active plant-derived natural products: Biomedical applications and toxicity

Pharmacologically active natural products have played a significant role in the history of drug development. They have acted as sources of therapeutic drugs for various diseases such as cancer and infectious diseases. However, most natural products suffer from poor water solubility and low bioavailability, limiting their clinical applications. The rapid development of nanotechnology has opened up new directions for applying natural products and numerous studies have explored the biomedical applications of nanomaterials loaded with natural products. This review covers the recent research on applying plant-derived natural products (PDNPs) nanomaterials, including nanomedicines loaded with flavonoids, non-flavonoid polyphenols, alkaloids, and quinones, especially their use in treating various diseases. Furthermore, some drugs derived from natural products can be toxic to the body, so the toxicity of them is discussed. This comprehensive review includes fundamental discoveries and exploratory advances in natural product-loaded nanomaterials that may be helpful for future clinical development.

Mesoporous Silica Particles Retain Their Structure and Function while Passing through the Gastrointestinal Tracts of Mice and Humans

Mesoporous silica particles (MSPs) can be used as food additives, clinically for therapeutic applications, or as oral delivery vehicles. It has also been discussed to be used for a number of novel applications including treatment for diabetes and obesity. However, a major question for their possible usage has been if these particles persist structurally and retain their effect when passing through the gastrointestinal tract (GIT). A substantial breaking down of the particles could reduce function and be clinically problematic for safety issues. Hence, we investigated the biostability of MSPs of the SBA-15 kind prepared at large scales (100 and 1000 L). The MSPs were orally administered in a murine model and clinically in humans. A joint extraction and calcination method was developed to recover the MSPs from fecal mass, and the MSPs were characterized physically, structurally, morphologically, and functionally before and after GIT passage. Analyses with N2 adsorption, X-ray diffraction, electron microscopy, and as a proxy for general function, adsorption of the enzyme α-amylase, were conducted. The adsorption capacity of α-amylase on extracted MSPs was not reduced as compared to the pristine and control MSPs, and adsorption of up to 17% (w/w) was measured. It was demonstrated that the particles did not break down to any substantial degree and retained their function after passing through the GITs of the murine model and in humans. The fact the particles were not absorbed into the body was ascribed to that they were micron-sized and ingested as agglomerates and too big to pass the intestinal barrier. The results strongly suggest that orally ingested MSPs can be used for a number of clinical applications.

Lactose-Gated Mesoporous Silica Particles for Intestinal Controlled Delivery of Essential Oil Components: An In Vitro and In Vivo Study

Mesoporous silica microparticles functionalized with lactose for the specific release of essential oil components (EOCs) in the small intestine are presented. In vitro and in vivo intestinal models were applied to validate the microparticles (M41-EOC-L), in which the presence of lactase acts as the triggering stimulus for the controlled release of EOCs. Among the different microdevices prepared (containing thymol, eugenol and cinnamaldehyde), the one loaded with cinnamaldehyde showed the most significant Caco-2 cell viability reduction. On the other hand, interaction of the particles with enterocyte-like monolayers showed a reduction of EOCs permeability when protected into the designed microdevices. Then, a microdevice loaded with cinnamaldehyde was applied in the in vivo model of Wistar rat. The results showed a reduction in cinnamaldehyde plasma levels and an increase in its concentration in the lumen of the gastrointestinal tract (GIT). The absence of payload release in the stomach, the progressive release throughout the intestine and the prolonged stay of the payload in the GIT-lumen increased the bioavailability of the encapsulated compound at the site of the desired action. These innovative results, based on the specific intestinal controlled delivery, suggest that the M41-payload-L could be a potential hybrid microdevice for the protection and administration of bioactive molecules in the small intestine and colon.

Omeg@Silica: Entrapment and Stabilization of Sustainably Sourced Fish Oil

Fish oil rich in long-chain polyunsaturated fatty acids, vitamin D3 and carotenoid pigments have been sustainably extracted from anchovy fillet leftovers using biobased limonene. The oil is conveniently stabilized by adsorption on periodic mesoporous silicas. The simplicity of the process, the high load of fish oil, and the biocompatible nature of mesoporous silica support numerous forthcoming applications of this new class of "Omeg@Silica" materials.

Cisplatin delivery, anticancer and antibacterial properties of Fe/SBA-16/ZIF-8 nanocomposite

Nanoformulation involving biocompatible MOFs and magnetic nanocarriers is an emerging multifunctional platform for drug delivery and tumor imaging in targeted cancer therapeutics. In this study, a nanocomposite has been developed comprising Fe/SBA-16 and ZIF-8 (Fe/S-16/ZIF-8) through ultrasonication. The drug delivery of cisplatin was studied using an automated diffusion cell system equipped with a flow type Franz cell. The anticancer activity of Fe/S-16/ZIF-8 was studied in vitro in MCF-7, HeLa cells and Human Foreskin Fibroblast (HFF-1) cells. XRD and d-spacing measurements of Fe/S-16/ZIF-8 using TEM revealed the presence of cubic-structured Fe₃O₄, γ-Fe₂O₄ (magnetite), and α-FeOOH (goethite) over an SBA-16/ZIF-8 nanocomposite. The composite showed a surface area of 365 m² g⁻¹, a pore size of 8.3 nm and a pore volume of 0.33 cm³ g⁻¹. VSM analysis of Fe/S-16/ZIF-8 showed that it possessed paramagnetic behavior with a saturated magnetization value of 2.39 emu g⁻¹. The Fe²⁺/Fe³⁺ coordination environment was characterized using diffuse reflectance spectroscopy. The cisplatin drug delivery study clearly showed the synergistic effects present in Fe/S-16/ZIF-8 with over 75% of cisplatin release as compared to that of Fe/S-16 and ZIF-8, which showed 56% and 7.5%, respectively. The morphology analysis of CP/Fe/SBA-16/ZIF-8 using TEM showed an effective transit of nanoparticles into MCF-7 cells. The lethal concentration (LC₅₀) of Fe/SBA-16/ZIF-8 for MCF-7 and HeLa cells is 0.119 mg mL⁻¹ and 0.028 mg mL⁻¹ at 24 h, respectively. For HFF-1 cells, the LC₅₀ is 0.016 mg mL⁻¹. The antibiofilm activity of Fe/SBA-16/ZIF-8 was investigated against biofilm-forming strains of drug resistant P. aeruginosa and MRSA by a microtiter tissue culture plate assay. Overall, nanosized ZIF-8 with a bioactive alkaloid imidazole inside the 3D cage type of SBA-16 pores is found to exhibit both anticancer and antibacterial properties. A Fe/S-16/ZIF-8 composite could be effectively used as a drug and drug delivery system against cancer and promote antibacterial activity.

The role of nano ZIF-8 in a Fe/SBA-16/ZIF composite has been explored as a potential anticancer drug and drug delivery system.

Anchoring Gated Mesoporous Silica Particles to Ethylene Vinyl Alcohol Films for Smart Packaging Applications

This work is a proof of concept for the design of active packaging materials based on the anchorage of gated mesoporous silica particles with a pH triggering mechanism to a packaging film surface. Mesoporous silica micro- and nanoparticles were loaded with rhodamine B and functionalized with N-(3-trimethoxysilylpropyl)diethylenetriamine. This simple system allows regulation of cargo delivery as a function of the pH of the environment. In parallel, poly(ethylene-co-vinyl alcohol) films, EVOH 32 and EVOH 44, were ultraviolet (UV) irradiated to convert hydroxyl moieties of the polymer chains into ⁻COOH functional groups. The highest COOH surface concentration was obtained for EVOH 32 after 15 min of UV irradiation. Anchoring of the gated mesoporous particles to the films was carried out successfully at pH 3 and pH 5. Mesoporous particles were distributed homogeneously throughout the film surface and in greater concentration for the EVOH 32 films. Films with the anchored particles were exposed to two liquid media simulating acidic food and neutral food. The films released the cargo at neutral pH but kept the dye locked at acidic pH. The best results were obtained for EVOH 32 irradiated for 15 min, treated for particle attachment at pH 3, and with mesoporous silica nanoparticles. This opens the possibility of designing active materials loaded with antimicrobials, antioxidants, or aromatic compounds, which are released when the pH of the product approaches neutrality, as occurs, for instance, with the release of biogenic amines from fresh food products.

Improving the Antimicrobial Power of Low-Effective Antimicrobial Molecules Through Nanotechnology

The objective of this work was on the one hand to assess the antibacterial activity of amines anchored to the external surface of mesoporous silica particles against Listeria monocytogenes in comparison with the same dose of free amines as well. It was also our aim to elucidate the mechanism of action of the new antimicrobial device. The suitability of silica nanoparticles to anchor, concentrate and improve the antimicrobial power of polyamines against L. monocytogenes has been demonstrated in a saline solution and in a food matrix. Moreover, through microscope observations it has been possible to determine that the attractive binding forces between the positive amine corona on the surface of nanoparticles and the negatively charged bacteria membrane provoke a disruption of the cell membrane. The surface concentration of amines on the surface of the nanoparticles is so effective that immobilized-amines were 100 times more effective in killing L. monocytogenes bacteria than the same amount of free polyamines. This novel approach for the creation of antimicrobial nanodevices opens the possibility to put in value the antimicrobial power of natural molecules that have been discarded because of its low antimicrobial power.

PRACTICAL APPLICATION

Consumers demand for high-quality products, free from chemical preservatives, with an extended shelf-life. In this study, a really powerful antimicrobial agent based on a nanomaterial functionalized with a non-antimicrobial organic molecule was developed as a proof of concept. Following this approach it could be possible to develop a new generation of natural and removable antimicrobials based on their anchoring to functional surfaces for food, agricultural or medical purposes.

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

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

Enhanced antimicrobial activity of essential oil components immobilized on silica particles

The antimicrobial activity of essential oils components (EOCs) is well-known. However, their high volatility and powerful aroma limit their application in the formulation of a wide range of food products. In this context, the antimicrobial activity of carvacrol, eugenol, thymol and vanillin grafted onto the surface of three silica supports with different morphologies, textural properties and chemical reactivities (fumed silica, amorphous silica and MCM-41) was evaluated herein. Materials characterization revealed a good immobilization yield and all the devices showed a micro-scale particle size. Sensory evaluation revealed that sensory perception of EOCs decreases after covalent immobilization. Moreover, immobilization greatly enhanced the antimicrobial activity of the essential oil components against Listeria innocua and Escherichia coli compared to free components. The incorporation of EOCs immobilized on silica particles into pasteurized milk inoculated with L. innocua demonstrated their effectiveness not only for in vitro conditions, but also in a real food system.

Protection of folic acid through encapsulation in mesoporous silica particles included in fruit juices

Folic acid (FA) is a synthetic vitamin commonly used for food fortification. However, its vulnerability to processing and storage implies loss of efficiency, which would induce over-fortification by processors to obtain a minimum dose upon consumption. Recent studies have indicated potential adverse effects of FA overdoses, and FA protection during processing and storage could lead to more accurate fortification. In addition, sustained vitamin release after consumption would help improve its metabolism. The objective of this work was to study controlled FA delivery and stability in fruit juices to reduce potential over-fortification risks by using gated mesoporous silica particles (MSPs). The obtained results indicated that FA encapsulation in MSPs significantly improved its stability and contributed to controlled release after consumption by modifying vitamin bioaccessibility. These results confirmed the suitability of MSPs as support for controlled release and protection of bioactive molecules in food matrices in different food production and storage stages.