Sol–gel one-pot synthesis in soft conditions of mesoporous silica materials ready for drug delivery system

The present work reveals a new and simple strategy, a one-step sol–gel procedure, to encapsulate a low water-soluble drug in silica mesostructured microparticles and to improve its release in physiological media. The synthesis of these new materials is based on the efficient solubilisation of a poorly water-soluble drug in surfactant micelles (Tween 80, a pharmaceutical excipient) which act as template for the silica network. A strict control of the sol–gel process and the parameters procedure in soft conditions (concentration, pH, temperature) was applied to reach the solubilisation limit of the drug in the micellar solution so as to optimise its encapsulation. Even if this one-pot procedure could appear limited by the low drug loading, it could provide an interesting alternative for the formulation of many recent highly active but very poorly soluble drugs.     

Light-triggered reversible assemblies of azobenzene-containing amphiphilic copolymer with β-cyclodextrin-modified hollow mesoporous silica nanoparticles for controlled drug release

Hollow mesoporous silica nanoparticles (HMSs) were modified by β-cyclodextrin via a "click" reaction, an amphiphilic copolymer with a trans-azobenzene structure was then assembled onto β-cyclodextrin to cover the surface of the HMSs. The prepared nanocomposites can release drugs in a "release-stop-release" manner by converting light irradiation.     

Photo-responsive nanoparticles for β-lapachone delivery in vitro

We reported a one-step encapsulation of indocyanine green (ICG) in ZIF-8 nanoparticles (NPs). The as-prepared ICG@ZIF-8 NPs possess an absorption band in the near infrared region and have the good photothermal conversion efficiency.     

A new method for loading mesoporous silica nanoparticles with drugs: Sol–gel synthesis using drug micelles as a template

It has been shown that mesoporous nanocontainers from SiO₂ may be obtained by the sol–gel synthesis using drug (Miramistin) micelles as a template. The nanocontainers resulting from the combination of the stages of their synthesis and loading are characterized by a very high content of the drug (no less than 0.9 g per 1 g of SiO₂). The kinetics of Miramistin desorption from the mesoporous particles into an aqueous medium has been studied under static and quasi-dynamic conditions. The desorption has been shown to rather strongly depend on pH. Possible mechanisms of the desorption process have been discussed.     

Combining mesoporous silica–magnetite and thermally-sensitive polymers for applications in hyperthermia

In this work, the synthesis strategy of a multifunctional system of [SBA-16/P(N-iPAAm)/Fe₃O₄] hybrids of interest for magneto-hyperthermia was explored. Magnetite nanoparticles coated by mesoporous silica were prepared by an alternative chemical route using neutral surfactant and without the application of any functionalization method. Monomer adsorption followed by in situ polymerization initiated by a radical was used to incorporate the hydrogel into the pore channels of the silica nanocomposite. Structural and magnetic characterization of the obtained materials was carried out by using thermal analysis, X-ray diffraction, N₂ adsorption desorption isotherms, ⁵⁷Fe Mössbauer spectroscopy, vibrating sample magnetometry and transmission electron microscopy. Measurements of alternating current magnetic-field-induced heating behaviour under different applied magnetic fields showed that the [SBA-16/P(N-iPAAm)/Fe₃O₄] hybrid here synthesized is suitable as a hyperthermia agent for biological applications.     

Core–shell nanoparticles of carboxy methyl cellulose and compritol-PEG for antiretroviral drug delivery

Multi-functional nanoparticles hold great promise for the effective treatment of many diseases. Zidovudine a commonly used anti-HIV drug, requires a delivery system for more effective treatment of AIDS. The present study focuses on the development of anti-viral drug-loaded hybrid nanoparticles (LPNs) of lipid and polymer consisting of carboxy methyl cellulose—zidovudine (AZT) core enclosed by a compritol (Comp)-polyethylene glycol shell. The characterization of drug loaded LPNs was done using TEM, DLS and FT-IR analysis. The drug loading efficiency, drug release, blood compatibility, MTT assay and cell uptake studies were carried out using the LPNs. The synthesized nanoparticles exhibited core–shell morphology with an average size of 161.65 ± 44.06 nm; the LPN also demonstrated 82% drug encapsulation efficiency with slow drug release behaviour. The hybrid nanoparticles were found to be blood compatible and non toxic. The rhodamine-labeled hybrid nanoparticles were also found to effectively enter the brain cells. The novel hybrid drug delivery system shows controlled drug release, biocompatibility and high drug loading efficiency. These LPNs obtained from natural polymers can provide an excellent platform for designing systems for targeted drug delivery.     

β-Cyclodextrin derivatives hybrid Fe3O4 magnetic nanoparticles as the drug delivery for ketoprofen

β-Cyclodextrin (β-CD) and its derivatives carboxymethyl-β-CD (CM-β-CD) and 2,6-dimethyl-β-CD (DM-β-CD) modified magnetic nanoparticles (CD-MNPs) were synthesized via layer-by-layer method. CDs grafted onto Fe₃O₄ MNPs were demonstrated by transmission electron microscopy, Fourier transform infrared and Zeta potential. Magnetic properties of CM-β-CD-MNPs, DM-β-CD-MNPs and β-CD-MNPs were characterized by vibrating sample magnetometer and the magnetic saturation values were 47, 46 and 44 emu g^?1, respectively. CD-MNPs as drug carriers were investigated by inclusion behavior and in vitro release using ketoprofen (KP) as a model drug. The maximum adsorption quantities of CM-β-CD-MNPs, DM-β-CD-MNPs and β-CD-MNPs for KP were 37.03, 7.63 and 25.12 mg g^?1, respectively, and the loading behaviors followed the Langmuir adsorption isotherm model with monolayer adsorption. The release profiles of KP released from KP-loaded CD-MNPs were rapid in initial 60 min and then gradually tend to level off, the release efficiency order was CM-β-CD-MNPs > β-CD-MNPs > DM-β-CD-MNPs, which was consistent with the order of inclusion capability. Therefore, the CD-MNPs were promising candidates for drug delivery.     

Facile synthesis of mesoporous silica nanoparticles with controlled morphologies using water–acetone media

Mesoporous silica nanoparticles with controlled morphologies including nanococoons, nanorods and nanospheres have been synthesized in water–acetone media at room temperature using cetyltrimethylammonium bromide (CTAB) as the template. The obtained nanoparticles generally show hexagonal-like mesoporous structures with average pore size ranging from 2.7 to 3.3 nm and surface area from 806 to 1055 m²/g, respectively. It was found that the changes in water-to-acetone molar ratios have a dramatic impact on the morphologies of the mesoporous silica with different surface roughness, probably due to the solvent influence on the rate of the hydrolysis of tetraethoxy silane (TEOS) and the polymerization of inorganic species. Interestingly, the morphology of the mesoporous silica products can be controlled in shape from nanococoons to nanorods to nanospheres just by decreasing the water-to-acetone molar ratio from 75 to 30 to 15, respectively. From transmission electron microscopy (TEM) images, it was observed that mesoporous parallel channels run along the short axis in some areas in the nanorods, whereas the radially arranged mesopore channels are present in the nanospheres. Additionally, hydrothermal treatment leads to rougher surfaces while retaining the morphologies and nanostructures of these mesoporous silicas.     

Study on the α-cyclodextrin/poly(ethylene glycol) self-assembly supramolecular nanoparticles for drug delivery

This paper reports the synthesis and drug delivery properties of a novel supramolecular nanoparticle.α-Cyclodextrins(α-CD) were threaded on cinnamic acid modified poly(ethylene glycol) to form inclusion complex nanoparticles by supramolecular self-assemble.The anti-tumor drug doxorubicin was loaded in the nanoparticles and released in vitro to study the drug release behavior and the anti-tumor effects.The structure and morphology of the nanoparticles were characterized by nuclear magnetic resonance,X-ray di...     

Ratiometric pH sensor based on mesoporous silica nanoparticles and Förster resonance energy transfer

Incorporation of a dual-FRET dye pair into mesoporous silica nanoparticles yields sensitive and sensing-range tunable nanosensors with good reversibility that can be used for ratiometric pH measurements under a single-wavelength excitation.     

Folate binding protein—Outlook for drug delivery applications

Serum proteins represent an important class of drug and imaging agent delivery vectors. In this minireview, key advantages of using serum proteins are discussed, followed by the particular advantages and challenges associated with employing soluble folate binding protein. In particular, approaches employing drugs that target folate metabolism are reviewed. Additionally, the slow-onset, tightbinding interaction of folate with folate binding protein and the relationship to a natural oligomerization mechanism is discussed. These unique aspects of folate binding protein suggest interesting applications for the protein as a vector for further drug and imaging agent development.     

Enzymes immobilized in mesoporous silica: A physical–chemical perspective

Mesoporous materials as support for immobilized enzymes have been explored extensively during the last two decades, primarily not only for biocatalysis applications, but also for biosensing, biofuels and enzyme-controlled drug delivery. The activity of the immobilized enzymes inside the pores is often different compared to that of the free enzymes, and an important challenge is to understand how the immobilization affects the enzymes in order to design immobilization conditions that lead to optimal enzyme activity. This review summarizes methods that can be used to understand how material properties can be linked to changes in enzyme activity. Real-time monitoring of the immobilization process and techniques that demonstrate that the enzymes are located inside the pores is discussed by contrasting them to the common practice of indirectly measuring the depletion of the protein concentration or enzyme activity in the surrounding bulk phase. We propose that pore filling (pore volume fraction occupied by proteins) is the best standard for comparing the amount of immobilized enzymes at the molecular level, and present equations to calculate pore filling from the more commonly reported immobilized mass. Methods to detect changes in enzyme structure upon immobilization and to study the microenvironment inside the pores are discussed in detail. Combining the knowledge generated from these methodologies should aid in rationally designing biocatalyst based on enzymes immobilized in mesoporous materials.     

Synthesis of mesoporous Stöber silica nanoparticles: the effect of secondary and tertiary alkanolamines

The effect of secondary (diethanolamine) and tertiary (triethanolamine) alkanolamines as catalysts on the formation of mesoporous Stöber silica nanoparticles by sol–gel method was studied. The particles were characterized by thermogravimetry and differential thermal analysis, Fourier transform infrared spectroscopy, N₂ physisorption measurements, and field emission scanning electron microscopy. By using ammonia and different alkanolamines as catalysts, the Brunauer–Emmet–Teller (BET) surface area and pore volume increased in the order of ammonia < diethanolamine < triethanolamine. A maximum BET surface area of 140.1 m² g^?1 and pore volume of 0.66 cm³ g^?1 were obtained from triethanolamine catalyzed silica particles. The average particle size of silica prepared by ammonia and different alkanolamines as catalysts decreased in the order of ammonia > diethanolamine > triethanolamine. The role of different alkanolamines on the textural properties and particle size of silica is explained in terms of their relative steric hindrance and basicity.     

Photo and redox dual-stimuli-responsive β-cyclodextrin-ferrocene supramolecules for drug delivery

Abstract

Amphiphilic photo and redox dual-stimuli-cleavable β-cyclodextrin-ferrocene supramolecules were synthesized through noncovalent interactions of ferrocene (Fc) and β-cyclodextrin (β-CD) born by 5-hydroxy-2-nitrobenzyl alcohol (ONB), a photodegradable linker between the β-CD and poly(4-substituted-?-caprolactone) (PXCL _n ) chain. The terminal host–guest MPEG-Fc/β-CD-ONB-PXCL _n complex can formed micelles in the aqueous phase. The critical micelle concentration ranged from 3.16 to 11.50?mg L^?1. The drug-loading content and drug entrapment efficiency of the complex were lower than those of the parent β-CD. When exposed to ultraviolet irradiation and hydrogen peroxide, complex micelles could dissociate and efficiently release the loaded drug. Nanoparticles exhibited almost no toxicity at concentrations up to 1000?μg mL^?1. The uptake of doxorubicin-incorporated micelles by HeLa cells was faster than that of free doxorubicin within the first 5?min. DOX-loaded MPEG₄₅-Fc/β-CD-ONB-PMCL₂₃ micelles effectively inhibited the proliferation of HeLa cells with a half maximal inhibitory concentration (IC₅₀) of 3.8?µg mL^?1.     

Multifunctional hybrid nanoconjugates for efficient in vivo delivery of immunomodulating oligonucleotides and enhanced antitumor immunity

A winning combination: Multifunctional hybrid nanoconjugates (HNCs) based on polymer nanoparticles containing quantum dots (QDs) conjugated with CpG oligonucleotides (as a ligand for TLR9) and STAT3 siRNAs (to suppress the immune response) have been synthesized. These HNCs were shown to synergistically enhance the antitumor immune response in dendritic cells and in tumor-bearing mice.     

Reduced graphene oxide-encapsulated mesoporous silica as sulfur host for lithium–sulfur battery

Journal of Solid State Electrochemistry - With up to fivefold higher in energy density vs. lithium-ion battery, lithium–sulfur (Li–S) battery is a compelling energy storage system,...     

Alginate–chitosan micro- and nanoparticles for transmucosal delivery of proteins

The properties of protein-containing micro- and nanoparticles that were produced from alginate and chitosan using the methods of layer-by-layer polyelectrolyte adsorption and ionotropic gelation have been compared. The encapsulation efficiency of proteins (aprotinin, interferon, and human insulin), the size and ζ-potential of the particles, the mucin binding, and the protein release under physiological conditions have been studied. The prospects for the possible mucosal application of the particles are discussed.     

An amphiphilic dendrimer for effective delivery of small interfering RNA and gene silencing in vitro and in vivo

An amphiphilic dendrimer bearing a hydrophobic alkyl chain and hydrophilic poly(amidoamine) dendrons is able to combine the advantageous features of lipid and dendrimer vectors to deliver a heat shock protein?27 siRNA and produce potent gene silencing and anticancer activity in?vitro and in?vivo in a prostate cancer model. This dendrimer can be used alternatively for treating various diseases.     

Recent progresses of exosome–liposome fusions in drug delivery

Exosomes are membrane-bound nanoscale extracellular vesicles, which produced by almost all organisms.Due to the excellent biocompatibility, long circulation time as well as low immunogenicity, exosomes as naturally-derived drug delivery carriers have experienced explosive growth over the past decades. However, issues such as insufficient loading efficiency, heterogeneous delivery efficiency, uncontrollable targeting ability, and low production limit their wide application. Recently, the emerging...