Pores Of Mesoporous Silica Nanoparticles Research Articles

Modification of Mesoporous Silica Surface by Immobilization of Functional Groups for Controlled Drug Release

This paper introduces the synthesis of mesoporous silica nanoparticles (MSNs) with three different groups such as amine, thiol, and sulfonic acid, along the internal surface. Trimethyl[3-(trimethoxysilyl)propyl]ammonium chloride was used to modify the external surface of the nanomaterials. Such materials allow control of the drug release from MSN pores. Multifunctional MSNs were loaded with doxycycline (Doxy) to study their capacities and uploading time. The loading profile indicates that sulfonic groups in the internal surface were the most efficient surfaces with a loading capacity of ca. 35% in 90 min in acidic media.

Prodrug-Based Nanoreactors with Tumor-Specific In Situ Activation for Multisynergistic Cancer Therapy

Efficient drug delivery into tumor cells while bypassing many biological barriers is still a challenge for cancer therapy. By taking advantage of the palladium (Pd)-mediated in situ activation of a prodrug and the glucose oxidase (GOD)-based β-d-glucose oxidation reaction, we developed a multisynergistic cancer therapeutic platform that combined doxorubicin (DOX)-induced chemotherapy with GOD-mediated cancer-orchestrated oxidation therapy and cancer starvation therapy. In the present work, we first synthesized DOX prodrugs (pDOXs) and temporarily assembled them with β-cyclodextrins to reduce their toxic side effects. Then, a nanoreactor was constructed by synthesizing Pd0 nanoparticles in situ within the pores of mesoporous silica nanoparticles for the conversion of pDOX into the active anticancer drug. Furthermore, GOD was introduced to decrease the pH of the tumor microenvironment and induce cancer-orchestrated oxidation/starvation therapy by catalyzing β-d-glucose oxidation to form hydrogen peroxide (H2O2) and gluconic acid. Our study provides a new strategy that employs a cascade chemical reaction to achieve combined orchestrated oxidation/starvation/chemotherapy for the synergistic killing of cancer cells and the suppression of tumor growth.

Matrix Metalloproteinase-Responsive Mesoporous Silica Nanoparticles Cloaked with Cleavable Protein for "Self-Actuating" On-Demand Controlled Drug Delivery for Cancer Therapy.

The tumour site-specific stimulus responsiveness of smart drug delivery systems gives a unique system for effective therapeutic delivery with reduced toxic effects of conventional chemotherapeutic drugs. In this work, matrix metalloproteinase-2 (MMP-2)-responsive mesoporous silica nanoparticles (MSNs) were synthesized and assessed for "self-actuating" on-demand controlled drug delivery for cancer therapy. MMPs are members of protease enzymes that are generally overexpressed in cancerous tissues in all stages of cancer. MSNs have attracted significant consideration as a potential delivery system because of their robust and versatile physicochemical properties suitable to deliver the therapeutic payload. Cisplatin (Cis) was used as a model drug, which was incorporated into MSNs to evaluate targeting of lung cancer cells and their release kinetics. In this delivery system, collagen was coated on the surface of Cis-loaded MSNs (Cis-MSN) to form a capping layer, resulting in collagen-coated MSNs (Cis-col-MSN). Under normal cell conditions, a collagen-capping coat efficiently forbids the release of Cis molecules from Cis-col-MSN. The tumor microenvironment would lead to augmented drug release because of the uncapping of collagen from MSN pores due to the presence of overexpressed MMP-2 enzyme and the ensuing controlled drug release. MMP-responsive experiments have shown augmented enzyme triggered drug release. The cellular uptake and cytocompatibility studies in A549 adenocarcinomic lung cancer cell lines demonstrated that this nanocarrier could be efficiently endocytosed in 24 h and have shown favorable biocompatibility with the cells. Cytotoxicity results of Cis-col-MSN demonstrated dose-dependent toxicity. The efficacy of the Cis-col-MSN significantly enhanced with the supplementation of MMP-2 enzyme with increasing concentrations in the cell culture milieu. The efficacy of formulation was attributed to significantly enhance reactive oxygen species, cell cycle arrest, and apoptosis. It is expected that Cis-col-MSN promises a pragmatic approach to constructing an "on-demand" smart drug delivery system to deliver a therapeutic payload at the tumor site only.

Tumor targeted delivery of umbelliferone via a smart mesoporous silica nanoparticles controlled-release drug delivery system for increased anticancer efficiency.

Herein, a mesoporous silica nanoparticle (MSN) based biocompatible, targeted and controlled drug delivery system has been synthesized for tumor tissue-specific drug delivery. Umbelliferone, a natural coumarin derivative was loaded into the pores of MSN and capped with pH-sensitive poly acrylic acid (PAA). For targeted delivery of umbelliferone in tumor tissue, folic acid (FA) was grafted onto the surface of drug-loaded and PAA-coated MSN. The successful construction of the nanohybrid (Umbe@MSN-PAA-FA) was confirmed by performing a series of characterization. The synthesized pH-responsive nanohybrid showed diameter of around 50nm with overall negative surface charge and drug loading content of 12.56%. In vitro study showed that the nanohybrid caused significant cytotoxicity through the induction of both oxidative stress as well as mitochondrial damage in folate receptor over-expressed in human breast cancer cell, MCF-7 compared with free umbelliferone. In vivo study also exhibited that the nanohybrid effectively reduced tumor growth in tumor-bearing mice compared with free umbelliferone due to the enlarged bioavailability of the drug in tumor tissue. Besides, the nanohybrid did not exhibit any significant sign of systemic toxicity in other vital organs. Together, the study denoted that PAA and FA functionalized MSN controlled-drug delivery system could assist to increase the anticancer potential of umbelliferone.

Design and characterization of dual responsive mesoporous silica nanoparticles for breast cancer targeted therapy

The main reason for limited efficacy of anticancer drug is the poor accretion of administered amount of drug within the tumor. Here, chitosan folate capped dual responsive mesoporous silica nanoparticles (MSNs) which can actively target cancer cells, and provide burst release of loaded anticancer drug within tumor cells and ultimately leading to improved therapeutic efficacy were synthesized. MSNs were synthesized using most economic silica source, sodium silicate. Doxorubicin (DOX) was loaded within the pores of MSNs and these drug loaded MSNs were first reacted with cystamine dihydrochloride followed by capping with chitosan-folate conjugate (CH-FA) to produce dual (redox and pH) responsive nanoparticles with the ability to actively target breast cancer cells. A triggered release of DOX from MSNs under acidic redox (pH 5.5, 10 mM GSH) environment was confirmed by in vitro release studies. The formulation exhibited 2.14 and 1.65 folds higher cytotoxicity than free drug against MCF-7 and MDA-MB-231 cells. DOX-MSN-SS-CH-FA showed superior tumor suppressing activity as compared to DOX-MSN or DOX alone in the treatment of Ehrlich Ascites Carcinoma (EAC) induced breast cancer with significantly reduced hematological and organ specific toxicities associated with DOX treatment.

Synthesis of lactoferrin mesoporous silica nanoparticles for pemetrexed/ellagic acid synergistic breast cancer therapy

Despite the clinical approval of few nanomedicines for cancer therapy, some drawbacks still impede their improved efficiency including low drug loading, off-target toxicity and development of multi-drug resistance. Herein, lactoferrin (Lf)-coupled mesoporous silica nanoparticles (MSNPs) were developed for combined delivery of the cytotoxic drug pemetrexed (PMT) and the phytomedicine ellagic acid (EA) for synergistic breast cancer therapy. While the hydrophobic EA was physically encapsulated within the pores of MSNPs via the adsorptive properties of MSNPs and the electrostatic interactions between the negatively charged EA and positively charged amino modified MSNs, the highly water soluble PMT was chemically anchored to the Lf shell through chemical conjugation to the surface of lactoferrin coated MSNPs by carbodiimide reaction to avoid pre-mature drug release and systemic toxicity. The dual drug-loaded Lf-MSNPs (284 nm) demonstrated a sequential faster release of EA followed by a sustained release of PMT. The dual drug-loaded Lf-MSNPs exhibited highest cytotoxicity against MCF-7 (Michigan Cancer Foundation-7) breast cancer cells as revealed by the lowest combination index (CI = 0.885) compared to free drugs. The combination index value (< 1) revealed synergy between both loaded drugs. Furthermore, high cellular uptake of the nanocarriers into MCF-7 breast cancer cells was observed via Lf-receptor mediated endocytosis. Altogether, the dual drug-loaded Lf-targeted MSNPs showed to be a promising carrier for breast cancer therapy through triggering different signaling pathways, and hence overcoming the multi-drug resistance and minimizing the systemic toxicity.

Host-guest fabrication of dual-responsive hyaluronic acid/mesoporous silica nanoparticle based drug delivery system for targeted cancer therapy

In this paper, a targeting hyaluronic acid (HA)/mesoporous silica nanoparticle (MSN) based drug delivery system (DDS) with dual-responsiveness was prepared for cancer therapy. To avoid the side reaction between the anti-cancer drug doxorubicin hydrochloride (DOX) and HA, host-guest interaction was applied to fabricate the DDS named DOX@MSN-SS-N=C-HA. The “nanocontainer” MSN was modified with benzene ring via both pH-sensitive benzoic imine bond and redox-sensitive disulfide linkage. When DOX was loaded in the pores of MSN, the channels were then capped by the “gatekeeper” β-CD grafted HA (HA-g-CD) through host-guest interaction between β-CD and benzene. HA endowed the drug carriers with the targeting capability in CD44 over-expressed cancer cells. After cellular uptake, the carriers could rapidly release DOX for cell apoptosis due to both the hydrolysis of benzoic imine bond at low pH and the cleavage of disulfide bond at a high concentration of glutathione (GSH) intracellular. In vitro drug release studies and in vitro cytotoxicity studies were taken to investigate the dual-responsiveness of the carriers. And the CD44-receptor mediated cancer cell targeting capability was investigated as well. In conclusion, the targeted dual-responsive complex DDS fabricated through host-guest interaction has promising potential in cancer therapy.

Ligand-free gold nanoclusters confined in mesoporous silica nanoparticles for styrene epoxidation.

We present a novel approach to produce gold nanoclusters (Au NCs) in the pores of mesoporous silica nanoparticles (MSNs) by sequential and controlled addition of metal ions and reducing agents. This impregnation technique was followed to confine Au NCs inside the pores of MSNs without adding external ligands or stabilizing agents. TEM images show a uniform distribution of monodisperse NCs with an average size of 1.37 ± 0.4 nm. Since the NCs are grown in situ in MSN pores, additional support and high temperature calcination are not required to use them as catalysts. The use of Au NC/MSNs as a catalyst for the epoxidation of styrene in the presence of tert-butyl hydroperoxide (TBHP) as a terminal oxidant resulted in an 88% conversion of styrene in 12 h with a 74% selectivity towards styrene epoxide. Our observations suggest that this remarkable catalytic performance is due to the small size of Au NCs and the strong interaction between gold and the MSNs. This catalytic conversion is environmentally friendly as it is solvent free. We believe our synthetic approach can be extended to other metal NCs offering a wide range of applications.

Imprinting the location of an in-built RAFT agent and selective grafting of polymer chains inside or outside the pores of mesoporous silica nanoparticles

Abstract Mesoporous silica nanoparticles (MSNs) primed with RAFT agent were synthesized via co-condensation of tetraethoxysilane (TEOS) and organoalkoxysilane based RAFT agent. The nature of the R group in organoalkoxysilane based RAFT agent was varied in order to control the preferential location of polymer grafting. Two different RAFT agents were prepared, one RAFT agent contained phenyl ethyl as R group, and other RAFT agent contained isobutyric acid as R group. The stability of the organoalkoxysilane based RAFT agents was confirmed employing UV–Visible spectroscopy and 1H solution NMR spectroscopy techniques. Succeeding this RAFT functionalized MSNs preparation, surface-initiated RAFT polymerization was carried out using N-isopropylacrylamide (NIPAM). RAFT and polymer functionalized MSNs were then characterized by diverse techniques such as FT-IR, TGA, UV–Visible spectroscopy, surface area measurement, X-ray photoelectron spectroscopy (XPS), 13C and 29Si solid-state NMR spectroscopy. The outcome of utilizing different types of organoalkoxysilane based RAFT agent on the morphology was examined using SEM and TEM. Spherical and cuboid shape was observed in the case of RAFT–COOH–MSNs and RAFT-Ph-MSNs respectively. Higher percentage of polymer grafting was observed in case of PNIPAM–COOH–MSNs in comparison to PNIPAM-Ph-MSNs. The realization of preferential grafting of polymer on exterior or interior surface of RAFT MSNs was established using pore size/volume analysis by BET as well as by XPS. The characteristic resonances in 13C and 29Si solid-state NMR and characteristic vibrations in FT-IR, confirms successful synthesis of organic-inorganic hybrids. The analysis of thermoresponsiveness of PNIPAM grafted MSNs was experimented by drug loading and release studies at different temperatures as well as by confocal laser scanning microscopy.

Poly(amino acid)/ZnO/mesoporous silica nanoparticle based complex drug delivery system with a charge-reversal property for cancer therapy

Negative-to-positive charge-reversal strategy employed in anti-cancer drug delivery systems (DDSs) can improve the utilization of the drugs as well as reduce their side effects efficiently. In this article, a complex DDS named DOX@MSN-ZnO-PLL-PLL(DMA) was prepared. Doxorubicin hydrochloride (DOX) was loaded in mesoporous silica nanoparticles (MSNs), which were then covered by ZnO in situ. Poly-L-lysine (PLL) and 2,3-dimethylmaleic anhydride functionalized PLL (PLL(DMA)) were finally coated on the nanoparticles through a Layer-by-Layer (LbL) assembly process with PLL(DMA) outside to obtain the carriers. The negative charged PLL(DMA) avoided the unspecific uptake of the carriers by normal cells at pH 7.4. While the charge-reversal property could reverse the zeta-potential of the carriers to positive in weakly acidic tumor tissues at pH 6.5, which promoted the cytophagy of the carriers by cancer cells. ZnO which blocked the pores of MSNs could be dissolved intracellular due to the more acidic environment in endosome/lysosome, and resulting in drug release for cancer cell apoptosis. Zeta-potential measurements, the in vitro cellular uptake behaviors as well as cellular cytotoxicity of the carriers at different pH values were investigated to prove the charge-reversal property. The in vitro drug release studies and the cellular cytotoxicity studies were also investigated to prove the controlled DOX release behavior of the carriers. In summary, the complex DDS with charge-reversal property should be of consideration in cancer therapy.

A facile strategy to fabricate a pH-responsive mesoporous silica nanoparticle end-capped with amphiphilic peptides by self-assembly.

A facile strategy with no modification processes was demonstrated to fabricate a pH-responsive end-capped mesoporous silica nanoparticle (MSN)-based drug delivery system (DDS). The simple but smart nanovalve systems were constructed by the self-assembly behavior of unbonded peptide-based amphiphile (P45) in the presence of Doxorubicin hydrochloride (Dox). A series of characterizations confirmed that the DDSs had been successfully fabricated. Dox molecules were entrapped by nanovalves in the pores of MSNs, and an in vitro release experiment demonstrated that the P45/Dox@MSNs exhibited "zero premature release" in the physical environment. However, an accelerated release was triggered by an acidic atmosphere in cellular cytosol. Moreover, detailed investigations confirmed that the enhanced cellular uptake of P45/Dox@MSNs due to the RGD motif of the nanovalves, exhibiting an obvious toxicity to cancer cells. Therefore, the DDSs constructed here can serve as a promising platform to realize targeted drug delivery and controlled drug release by using diversified bioactive native amphiphilic peptide.

Electrospun Antimicrobial Films of Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) Containing Eugenol Essential Oil Encapsulated in Mesoporous Silica Nanoparticles.

The main goal of this study was to develop poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) films with long-term antimicrobial capacity of interest in food packaging applications. To this end, eugenol was first highly efficiently encapsulated at 50 wt.-% in the pores of mesoporous silica nanoparticles by vapor adsorption. The eugenol-containing nanoparticles were then loaded in the 2.5–20 wt.-% range into PHBV by electrospinning and the resultant electrospun composite fibers were annealed at 155 °C to produce continuous films. The characterization showed that the PHBV films filled with mesoporous silica nanoparticles containing eugenol present sufficient thermal resistance and enhanced mechanical strength and barrier performance to water vapor and limonene. The antimicrobial activity of the films was also evaluated against foodborne bacteria for 15 days in open vs. closed conditions in order to simulate real packaging conditions. The electrospun PHBV films with loadings above 10 wt.-% of mesoporous silica nanoparticles containing eugenol successfully inhibited the bacterial growth, whereas the active films stored in hermetically closed systems increased their antimicrobial activity after 15 days due to the volatile portion accumulated in the system’s headspace and the sustained release capacity of the films. The resultant biopolymer films are, therefore, potential candidates to be applied in active food packaging applications to provide shelf life extension and food safety.

Priming the pores of mesoporous silica nanoparticles with an in-built RAFT agent for anchoring a thermally responsive polymer

Abstract RAFT mesoporous silica nanoparticles (MSNs) have been synthesized for the first time via co-condensation of an organoalkoxysilane RAFT agent, 1-phenylethyl(3-(triethoxysilyl)propyl)carbonotrithioate, with tetraethoxysilane (TEOS) in aqueous basic cetyltrimethylammonium bromide. The stability of the organoalkoxysilane RAFT agent during the synthesis of MSNs was established using solution NMR and UV–visible spectroscopies. The RAFT-MSNs were then used for elaboration with N-isopropylacrylamide (NIPAM) via controlled surface-initiated RAFT polymerization. The success of the incorporation of the organoalkoxysilane RAFT agent into the silica network, and polymerization of PNIPAM was confirmed with TGA, FT-IR, UV–visible spectroscopy, 13C and 29Si solid state NMR spectroscopy. The effect of the organoalkoxysilane based RAFT agent and PNIPAM grafting on the morphology, size and surface area of the resulting MSNs was investigated using SEM, TEM, XRD, DLS and BET analysis. The appearance of carbon signals in 13C solid state NMR, T signals in 29Si solid state NMR and C H stretching signals in FT-IR establishes that we have successfully obtained organic-inorganic hybrid materials. The pore area calculated using Barrett-Joyner-Halenda (BJH) analysis was 87.8 m2 g−1 for control-MSNs, 91.1 m2 g−1 for RAFT-MSNs and 132.9 m2 g−1 for PNIPAM-MSNs. The thermoresponsive behaviour of PNIPAM grafted inside the pores of MSNs was studied by dye as well as drug loading experiments at variable temperatures, followed by characterization using confocal laser scanning microscopy. The green and red fluorescence corresponding to fluorescein and doxorubicin respectively was strongly retained in the PNIPAM-MSNs after 24 h of incubation at 25 °C while lack of fluorescence after 24 h incubation at 35 °C, demonstrates the thermoresponsive behaviour of the polymer being grafted inside the pores of mesoporous silica nanoparticles.

π-π-π stacking for capturing-releasing Au clusters in meso-structured system

Smart delivery systems have received increasing attentions, due to the controllable capturing-releasing of the guests in many applications. Here, we propose a pH-responsive Au cluster capturing-releasing system using the mesoporous silica nanoparticles (MSNs) modified by organic molecular tweezers. The π-π-π stacking have been used to capture and stabilize the Au clusters in the pores of MSNs on the neutral or alkaline conditions, and responsively release and manipulate the Au clusters by adjustment of the pH value. The released Au clusters show high catalytic activity.

Influence of controlled functionalization of mesoporous silica nanoparticles as tailored fillers for thin-film nanocomposite membranes on desalination performance

Thin film nanocomposite (TFN) membranes comprising of controlled functionalized mesoporous silica nanoparticles (MSN) blended in the polyamide (PA) barrier layer were prepared via interfacial polymerization of m-phenylenediamine and trimesoyl chloride on a porous polyethersulfone support membrane. MSN were synthesized by sol-gel process and then functionalized with octadecyltrichlorosilane (OTS) using post-grafting method. The nitrogen adsorption measurements demonstrated that the hydrophobic alkyl chains of OTS can be grafted onto the internal pores of MSN or just be located on the external particle surface, depending on the functionalization procedure and the OTS concentration. The functionalized nanoparticles with a diameter of about 80 nm were thereafter easily dispersed in the organic phase during the interfacial polymerization. Evaluation of membranes’ performance was based on water and ethanol permeability measurements, in addition to salt rejection from aqueous solutions. The results indicated that the functionalization of the external surface of MSN only, without extension to the interior pores surface, significantly increased both water and ethanol permeabilities. Contrarily, the surface modification of the MSN internal pores only increased the permeability of ethanol and reduced the water permeability, mainly due to the hydrophobicity of OTS. The influence of nanoparticles loading, as well as the concentration of OTS and thus the extent of MSN functionalization on the separation performance of TFN membranes were also investigated. TFN membranes prepared using the optimized MSN functionalization and loading yielded up to 63% higher water permeability compared to the reference thin film composite membrane without sacrificing the membrane selectivity. This work clearly emphasizes the direct relationship between the internal pores of MSN as functional nanofiller in the PA barrier layer and increasing or decreasing the water permeability of resulting TFN membranes.

A label-free fluorescent aptasensor for detection of kanamycin based on dsDNA-capped mesoporous silica nanoparticles and Rhodamine B

Kanamycin is an aminoglycoside antibiotic that can be useful against both gram negative and positive bacteria. However, if its serum levels are not controlled properly, it can cause serious side effects like ototoxicity and nephrotoxicity. The aim of this study was to design a simple and rapid fluorescent aptasensor for detection of kanamycin, based on Aptamer/Complementary strand (dsDNA)-capped mesoporous silica nanoparticles (MSNs) and Rhodamine B as a fluorescent probe. The MSNs pores were filled with Rhodamine B and then gated with dsDNA. In the presence of kanamycin, the aptamer sequence was separated from its complementary strand (CS), so that, uncovered the pores and leading to leakage of Rhodamine B. Thus, a significant increase in the fluorescence intensity was observed. The relative fluorescence intensity showed a linearity range from 24.75 nM to 137.15 nM of kanamycin with a detection limit of 7.5 nM. The aptasensor also showed to be useful for detection of kanamycin in serum samples and was able to distinguish kanamycin from other antibiotics, resulting in a sensitive, rapid and inexpensive method for kanamycin detection.

Delivery of Abscisic Acid to Plants Using Glutathione Responsive Mesoporous Silica Nanoparticles.

An intracellular glutathione (GSH) responsive phytochemical delivery system based on thiol gated mesoporous silica nanoparticles (MSNs) was developed and tested on the model plant Arabidopsis thaliana. In the present study, monodispersed MSNs with particle diameters of ~20 nm and pore sizes of ~2.87 nm were synthesized and modified. Abscisic acid (ABA), a key phytohormone, was entrapped in the mesopores of MSNs and then the pore entrances of MSNs were covered with decanethiol gatekeepers through GSH-cleavable disulfide linkages. An in vitro release test of ABA from decanethiol gated MSNs proved that there was efficient loading and entrapment of phytochemicals in the absence of a GSH redox trigger. Most importantly, in planta experiments demonstrated that GSH-mediated release of ABA from the pores of MSNs significantly reduced the leaf stomatal aperture and inhibited water loss of treated plants. Moreover, compared with the usage of free ABA, the controlled release of the encapsulated phytohormone from MSNs markedly prolonged the expression of the ABA inducible marker gene (AtGALK2) and finally, improved the drought resistance ability of Arabidopsis seedlings under drought stress. Therefore, the concept of using short-chain molecules as gatekeepers to encapsulate biomolecules in MSNs was demonstrated. The application of MSNs with redox-responsive gatekeepers has been shown in this study to be a potential and efficient technique to deliver phytochemicals into plants and release them in a controllable fashion.

Multifunctional mesoporous silica nanoparticles as efficient transporters of doxorubicin and chlorin e6 for chemo-photodynamic combinatorial cancer therapy.

A multimodal nanocarrier based on mesoporous silica nanoparticles (MSNs) is developed to co-delivery photosensitizer chlorin e6 (Ce6) and chemotherapeutic agent doxorubicin (Dox) for cancer combination therapy. Ce6 was covalently conjugated with mesoporous silica nanoparticles, which could increase the loading efficiency, and allowed for photodynamic therapy. Doxorubicin was loaded into the pores of mesoporous silica nanoparticles to afford the dual drug delivery system Dox@MSNs-Ce6. These hybrid nanoparticles have an average diameter of about 100 nm and slightly negative charge of about -17 mV. The Dox@MSNs-Ce6 nanoparticles could efficiently enter into cancer cells. The cellular reactive oxygen species level in treated cells increased about 17 times, upon 660 nm light irradiation (10 mW/cm2, 2 min). More importantly, Dox@MSNs-Ce6 exhibited excellent synergistic effect through combining chemotherapy and photodynamic therapy against A549 lung cancer cells. Our work provides an effective strategy for anticancer drug delivery and combination therapy.

Structure-Activity Relationships of GAG Mimetic-Functionalized Mesoporous Silica Nanoparticles and Evaluation of Acyclovir-Loaded Antiviral Nanoparticles with Dual Mechanisms of Action.

Mesoporous silica nanoparticles (MSNs) are drug delivery agents that are able to incorporate drugs within their pores. Furthermore, MSNs can be functionalized by attachment of bioactive ligands on their surface to enhance their activity, and nanoparticles modified with glycosaminoglycan (GAG) mimetics inhibit the entry of herpes simplex virus (HSV) into cells. In this study, structure–activity relationships of GAGs attached to MSNs were investigated in relation to HSV-1 and HSV-2, and acyclovir was loaded into the pores of MSNs. The sulfonate group was demonstrated to be essential for antiviral activity, which was enhanced by incorporating a benzene group within the ligand. Loading acyclovir into GAG mimetic-functionalized MSNs reduced the viral infection, resulting in nanoparticles that simultaneously target two distinct viral pathways, namely, inhibition of viral entry and inhibition of DNA replication.

Selective Encapsulation and Enhancement of the Emission Properties of a Luminescent Cu(I) Complex in Mesoporous Silica

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%.