The direct delivery of specific proteins to live cells promises a tremendous impact for biological and medical applications, from therapeutics to genetic engineering. However, the process mostly ...involves tedious techniques and often requires extensive alteration of the protein itself. Herein we report a straightforward approach to encapsulate native proteins by using breakable organosilica matrices that disintegrate upon exposure to a chemical stimulus. The biomolecule‐containing capsules were tested for the intracellular delivery of highly cytotoxic proteins into C6 glioma cells. We demonstrate that the shell is broken, the release of the active proteins occurs, and therefore our hybrid architecture is a promising strategy to deliver fragile biomacromolecules into living organisms.
Speshell delivery: The construction of a breakable shell around proteins can be used for encapsulation and delivery of functional proteins. The shell comprises silica units that are held together with disulfide bridges. These stimulus‐responsive containers break into very small pieces upon contact with the cell environment, and the proteins retain their activity during encapsulation.
Mesoporous silica nanoparticles (MSNPs), 100 nm in size, incorporating a Cy5 fluorophore within the silica framework, are synthesized and loaded with the anti‐cancer drug temozolomide (TMZ), used in ...the treatment of gliomas. The surface of the particles is then decorated, using electrostatic interactions, with a polyarginine‐peptide nucleic acid (R8‐PNA) conjugate targeting the miR221 microRNA. The multi‐functional nanosystem thus obtained is rapidly internalized into glioma C6 or T98G cells. The anti‐miR activity of the PNA is retained, as confirmed by reverse transcription polymerase chain reaction (RT‐PCR) measurements and induction of apoptosis is observed in temozolomide‐resistant cell lines. The TMZ‐loaded MSNPs show an enhanced pro‐apoptotic effect, and the combined effect of TMZ and R8‐PNA in the MSNPs shows the most effective induction of apoptosis (70.9% of apoptotic cells) thus far achieved in the temozolomide‐resistant T98G cell line.
Multifunctional mesoporous silica nanoparticles (MSNPs) are extremely efficient for glioblastoma treatment, combining both excellent drug delivery and miRNA targeting. The MSNPs are easily synthesized and loaded with the anti‐cancer drug temozolomide (TMZ), and the particle surface is decorated with a polyarginine‐peptide nucleic acid conjugate (R8‐PNA) targeting miR221. The synergistic effect of TMZ and R8‐PNA has a dramatic impact on the human T98G tumor cell line.
The design and preparation of synthetic binders (SBs) applicable for small biomolecule sensing in aqueous media remains very challenging. SBs designed by the lock‐and‐key principle can be selective ...for their target analyte but usually show an insufficient binding strength in water. In contrast, SBs based on symmetric macrocycles with a hydrophobic cavity can display high binding affinities but generally suffer from indiscriminate binding of many analytes. Herein, a completely new and modular receptor design strategy based on microporous hybrid materials is presented yielding zeolite‐based artificial receptors (ZARs) which reversibly bind the neurotransmitters serotonin and dopamine with unprecedented affinity and selectivity even in saline biofluids. ZARs are thought to uniquely exploit both the non‐classical hydrophobic effect and direct non‐covalent recognition motifs, which is supported by in‐depth photophysical, and calorimetric experiments combined with full atomistic modeling. ZARs are thermally and chemically robust and can be readily prepared at gram scales. Their applicability for the label‐free monitoring of important enzymatic reactions, for (two‐photon) fluorescence imaging, and for high‐throughput diagnostics in biofluids is demonstrated. This study showcases that artificial receptor based on microporous hybrid materials can overcome standing limitations of synthetic chemosensors, paving the way towards personalized diagnostics and metabolomics.
Fluorescent artificial receptors that bind neurotransmitters with unprecedented affinity and selectivity in biofluids are introduced. They are based on nanozeolite hybrid materials and can be used for emission‐ and absorbance‐based detection of serotonin and dopamine in urine at physiological relevant concentration, for (two‐photon) imaging, and for label‐free enzymatic reaction monitoring in real time.
Short-channeled amino-functionalized-SBA-15 catalysts, NH
2pr(
x)-SBA-15, were synthesized. Their beneficial effects on base-catalyzed reactions were studied. The catalytic results showed that ...short-channeled catalysts showed much higher catalytic activity as well as higher selectivity to bulky product as compared to the corresponding amino-functionalized-SBA-15 catalysts having long channels.
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Amino-functionalized-SBA-15 catalysts with nanostructured hexagonal platelet morphologies were synthesized directly by using microwave synthesis from the hydrolysis and co-condensation of aminopropyltriethoxysilane (APTES) and sodium metasilicate under a strong acidic condition with the Pluronic P123 triblock copolymer as a structure-directing agent. The amino-functionalized-SBA-15 catalysts were proven by SEM and TEM techniques to have very short channels in the range of 200–300
nm perpendicular to the hexagonal platelet morphologies. These short-channeled catalysts were proven to be effective heterogeneous catalysts in liquid-phase reactions such as Knoevenagel and Claisen-Schmidt condensations as well as in Henry reaction. They exhibited greatly improved catalytic activities over the typical fibrous type SBA-15 catalyst having long channels. Obviously, the easy diffusion and rapid mass transfer of substrate into the short channel mesopores played important roles in the significant improvement in the catalytic activities.
The formation of hybrid silica‐based systems to study the effect of the confinement on the emission properties of self‐assembled platinum(II) complexes is reported. The complexes behave as ...surfactants since they possess a hydrophobic moiety and, on the ancillary ligand, a relatively long hydrophilic chain terminated with a positively charged group. The compounds, soluble in water, self‐assemble, even at very low concentration, in supramolecular structures which display an orange luminescence. The properties of the assemblies have been studied in detail and in order to stabilize these supramolecular architectures and to enhance their emission properties hybrid silica porous nanoparticles have been prepared. In particular the PtII complexes have been employed as co‐surfactant for the template formation of mesoporous silica nanoparticles (MSNs) using a sol gel synthesis. Interestingly, upon encapsulation in the silica pores, the platinum aggregates exhibit an emission profile similar in energy to the complexes assembled in solution, but the photoluminescence quantum yields of the hybrid systems are significantly higher (up to 45 %), and the excited state lifetimes much longer than those recorded in solution. Such enhancement of the photophysical properties together with the possibility to process the hybrid silica nanomaterials can pave the way to new type of emitters.
The inner light: Water‐soluble platinum complexes undergo self‐assembly and are used as co‐surfactant for the synthesis of mesoporous silica nanoparticles. Their confinement in the pores leads to an enhancement of the photophysical properties.
Multifunctional materials can be engineered by combining multiple chemical components, each conferring a well-defined function to the ensemble. Graphene is at the centre of an ever-growing research ...effort due to its combination of unique properties. Here we show that the large conformational change associated with the trans-cis photochemical isomerization of alkyl-substituted azobenzenes can be used to improve the efficiency of liquid-phase exfoliation of graphite, with the photochromic molecules acting as dispersion-stabilizing agents. We also demonstrate reversible photo-modulated current in two-terminal devices based on graphene-azobenzene composites. We assign this tuneable electrical characteristics to the intercalation of the azobenzene between adjacent graphene layers and the resulting increase in the interlayer distance on (photo)switching from the linear trans-form to the bulky cis-form of the photochromes. These findings pave the way to the development of new optically controlled memories for light-assisted programming and high-sensitive photosensors.
Purpose
Contact lenses have direct contact with the corneal surface and can induce sight‐threatening infection of the cornea known as Acanthamoeba keratitis. The objective of this study was to ...evaluate the dysprosium‐based nanoparticles (Dy‐based NPs), namely Fe3O4‐PEG‐Dy2O3 nanocomposites and Dy(OH)3 nanorods, as an active component against Acanthamoeba sp., as well as the possibility of their loading onto contact lenses as the drug administering vehicle to treat Acanthamoeba keratitis (AK).
Methods
The Dy‐based NPs were synthesized, and they were loaded onto commercial contact lenses. The loading content of the NPs and their release kinetics was determined based on the absorbance of their colloidal solution before and after soaking the contact lenses. The cytotoxicity of the NPs was evaluated, and the IC50 values of their antiamoebic activity against Acanthamoeba sp. were determined by MTT colorimetric assay, followed by observation on the morphological changes by using light microscopy. The mechanism of action of the Dy‐based NPs against Acanthamoeba sp. was evaluated by DNA laddering assays.
Results
The loading efficiencies of the Dy‐based NPs onto the contact lens were in the range of 30.6–36.1% with respect to their initial concentration (0.5 mg ml–1). The Dy NPs were released with the flux approximately 5.5–11 μg cm–2 hr–1, and the release was completed within 10 hr. The emission of the NPs consistently showed a peak at 575 nm due to Dy3+ ion, offering the possible monitoring and tracking of the NPs. The SEM images indicated the NPs are aggregated on the surface of the contact lenses. The DNA ladder assay suggested that the cells underwent DNA fragmentation, and the cell death was due most probably to necrosis, rather than apoptosis. The cytotoxicity assay of Acanthamoeba sp. suggested that Fe3O4‐PEG, Fe3O4‐PEG‐Dy2O3, Dy(NO3)3.6H2O and Dy(OH)3 NPs have an antiamoebic activity with the IC50 value being 4.5, 5.0, 9.5 and 22.5 μg ml–1, respectively.
Conclusions
Overall findings in this study suggested that the Dy‐based NPs can be considered as active antiamoebic agents and possess the potential as drugs against Acanthamoeba sp. The NPs could be loaded onto the contact lenses; thus, they can be potentially utilized to treat Acanthamoeba keratitis (AK).
We describe a synthetic approach to prepare new luminescent silica‐based materials through the encapsulation of a neutral copper(I) complex inside the pores of mesoporous silica nanoparticles (MSN). ...The copper(I) complex is present, in the solid state, as two polymorphs, blue and yellow emissive, and in solution it shows a pale yellow color that is also mirrored by an emission in the yellow‐orange region of the electromagnetic spectrum. The X‐ray structures of single crystals have been obtained for both polymorphs. The complex encapsulation in MSN is achieved by its entrapment inside micelles followed by condensation of the silica source. Interestingly, the entrapment leads to the isolation of only one species. Indeed, the compound inside the MSN exhibits remarkable photophysical properties, showing an intense blue emission in solution and in the solid state. Powder X‐ray diffraction of the hybrid materials proves that the complex entrapped in MSN is indeed the blue polymorph. The confinement provides not only a method to isolate only one form of the complex, but also a certain rigidity, more stability of the system by protection of the complex from undesirable oxidation, leading to a highly emissive material possessing a photoluminescence quantum yield of 65%.
This study aims to investigate the effect of alkaline pH on the bottom-up synthesis of nanocomposites (NCs) containing terbium sulfide nanoparticles (Tb2S3 NPs), where chitosan (CS) was employed as a ...capping agent, along with evaluation of the antibacterial activity of these NCs. The NCs were characterized using spectroscopy (FESEM-EDX, Raman, FTIR, XRD, XPS, and DLS), zeta-potential, and TGA. The results of FE-SEM, XPS, Raman, and FTIR characterization support the formation of CS-Tb2S3 NPs. A pH variation from 9 to 11 during composite formation was shown to affect the size and composition of NCs. The antibacterial activity of CS-Tb2S3 NCs was studied by coating onto commercial contact lenses, where the best loading efficiency of NCs was 48%. The NCs prepared at pH 10 (without contact lenses) had greater antibacterial activity against Staphylococcus aureus, with a zone of inhibition diameter of 7.15 mm. The coating of NCs onto commercial contact lenses was less effective for inhibition of Staphylococcus aureus, in contrast with the greater activity observed for tetracycline. CS-Tb2S3 NCs offer promising antimicrobial properties that can be further optimized by control of the surface loading and accessibility of Tb2S3 NPs through further study of the role of the chitosan capping agent, since steric effects due to CS are likely to attenuate antimicrobial activity via reduced electron transfer in such nanocomposite systems.
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