Types Of Mesoporous Silica Nanoparticles Research Articles

Acetylcholinesterase with mesoporous silica: Covalent immobilization, physiochemical characterization, and its application in food for pesticide detection.

Toxic contamination of commonly consumed food products and water due to food chain vulnerability via agricultural products and commodities is a serious health hazard. This study reports on Santa Barbara Amorphous (SBA-15), a type of mesoporous silica nanoparticles, for efficient and stable acetylcholinesterase (AChE) adhesion toward detection of toxic pesticides. AChE was immobilized to the inert framework of mesoporous materials viz. SBA-15 with a proficient hydrolytic response toward acetylthiocholine. The immobilized system acts as a biosensor for the detection of pesticides, which are organophosphorus compounds in food. Both the SBA-15 and immobilized SBA-15 were characterized to give an insight on the physiochemical and morphological modification properties. The enzyme activity was accessed by Ellman's spectrophotometric bioassay for bare and enzyme-immobilized SBA-15 that resulted in promising enzymatic activity with the counterpart. Enzyme stability was also studied, which exhibited that immobilized AChE retained its catalytic activity up to 60 days and retained 80% of the hydrolytic activity even at 37°C. On the basis of the success of immobilized enzyme (covalent) being inhibited by acetylthiocholine, the sensor was administered for the inhibition by monocrotophos and dimethoate that are used widely as pesticides in agricultural. The inhibitory concentration (IC50 ) value was found to be 2.5 ppb for monocrotophos and 1.5 ppb for dimethoate inhibiting immobilized AChE. This was verified using cyclic voltammetry, an electrochemical analysis thus proving that the SBA-15@AChE complex could be used as a sensitive and highly stable sensor for detecting the concentration of hazardous pesticide compounds.

Formulation and development of smart pH responsive mesoporous silica nanoparticles for breast cancer targeted delivery of anastrozole: In vitro and in vivo characterizations

Abstract In the present study, pH responsive, breast cancer targeted mesoporous silica nanoparticles (MSNs) have been developed as a carrier with a view to overcome problems such as non-selectivity, low cellular uptake and side effects associated with traditional chemotherapeutic drugs and improve their therapeutic efficacy. MCM-41 type of MSNs was synthesized using modified Stober's process and further modified by first reacting with (3-aminopropyl)triethoxysilane (APTES) and then succinic anhydride (SA) in order to obtain carboxylic acid functionalized MSN-COOH. Anastrozole was loaded into the MSNs and then capped with chitosan-folate conjugate. The MSNs were characterized by transmission electron microscopy (TEM), dynamic light scattering (DLS), zeta potential analysis, small angle x-ray scattering (SAXS), nitrogen adsorption/desorption analysis, differential scanning calorimetry (DSC), HPLC and UV-visible spectroscopy. In vitro release studies confirmed triggered drug release from these nanoparticles under acidic (pH 5.5) environment. Hemolysis study proved that the formulation was safe for intravenous administration. The formulation exhibited 1.5 folds higher cytotoxicity as compared to free drug indicating its improved therapeutic potency. The in-vivo anticancer activity of formulations was studied against Ehrlich Ascites Carcinoma (EAC) induced breast cancer in Balb C mice in which these nanoparticles showed superior anticancer activity. Excellent tumor suppressing activity was demonstrated by these nanoparticles against EAC induced breast cancer model.

Surface modified mesoporous silica nanoparticles as sustained-release gallic acid nano-carriers

Gallic acid (GA) is a natural and non-enzymatic antioxidant with known anticancer property. In the present work, two types of mesoporous silica nanoparticles (MSNs) were evaluated as a nano carrier for sustained release of GA. For this purpose, amine-functionalized (AP-MSNs) and chitosan coated (CS-MSNs) MSNs were synthesized, loaded by GA and then characterized by SEM, XRD, N2 adsorption isotherms and zeta-potential analysis. Optimum conditions for the loading of GA into the modified MSNs were obtained, and then in vitro GA release in simulated gastric fluid (SGF, pHs 1.4) was investigated. Cytotoxicity and cellular uptake of the modified MSNs were also investigated using MCF-7 cells. The encapsulation efficiency and loading capacity were measured 20.77% and 47.06% for AP-MSNs, respectively; while for CS-MSNs, they were obtained as 38.14% and 58.67%, respectively. Results showed that the rate of GA release from CS-MSNs was clearly slower than that from AP-MSNs. Moreover, according to the results, no cytotoxicity effects were observed in both AP-MSNs and CS-MSNs while CS-MSNs showed better killing potency against the MCF-7 cells. The cellular uptake of GA loaded CS-MSNs was also studied by TEM analysis and results showed their high biocompatibility and bioavailability.

Folic acid-conjugated mesoporous silica particles as nanocarriers of natural prodrugs for cancer targeting and antioxidant action.

Naturally derived prodrugs have a wide range of pharmacological activities, including anticancer, antioxidant, and antiviral effects. However, significant barriers inhibit their use in medicine, e.g. their hydrophobicity. In this comprehensive study, we investigated simple and effective nanoformulations consisting of amine-functionalized and conjugated with folic acid (FA) mesoporous silica nanoparticles (MSNs). Two types of MSNs were studied: KCC- 1, with mean size 324 nm and mean pore diameter 3.4 nm, and MCM - 41, with mean size 197 and pore diameter 2 nm. Both types of MSNs were loaded with three anticancer prodrugs: curcumin, quercetin, and colchicine. The nanoformulations were tested to target in vitro human hepatocellular carcinoma cells (HepG2) and HeLa cancer cells. The amine-functionalized and FA-conjugated curcumin-loaded, especially KCC-1 MSNs penetrated all cells organs and steadily released curcumin. The FA-conjugated MSNs displayed higher cellular uptake, sustained intracellular release, and cytotoxicity effects in comparison to non-conjugated MSNs. The KCC-1 type MSNs carrying curcumin displayed the highest anticancer activity. Apoptosis was induced through specific signaling molecular pathways (caspase-3, H2O2, c-MET, and MCL-1). The nanoformulations displayed also an enhanced antioxidant activity compared to the pure forms of the prodrugs, and the effect depended on the time of release, type of MSN, prodrug, and assay used. FA-conjugated MSNs carrying curcumin and other safe natural prodrugs offer new possibilities for targeted cancer therapy.

P.2.d.013 - The brain-gut axis profiles in patients with bipolar depression: a preliminary study

Mesoporous silica constitutes a recent development in nanotechnology. Mesoporous silica nanoparticles (MSNs) are promising drug delivery systems, raising great interest due to their excellent structural properties, such as high surface area, large pore volume, narrow pore size distribution, or tunable pore diameter. Several forms of MSNs exist according to their silica and surfactant content. The most common types of MSNs are Mobil Composition of Matter No. 41 (MCM-41) and Santa Barbara Amorphous-15 (SBA-15).This review gives a comprehensive account of the physicochemical properties of MSNs and describes the synthesis methods for controlling their properties and surface functionalization. In vitro and in vivo biocompatibility studies are also described. Their significant potential as biocompatible and stimuli-responsive drug delivery systems aiming for site-specific delivery and intracellular controlled drug release is discussed. The significance of their application against melanoma is particularly emphasized, highlighting their importance in cancer therapy.

Mesoporous silica nanoparticles (MSNs)-based organic/inorganic hybrid nanocarriers loading 5-Fluorouracil for the treatment of colon cancer with improved anticancer efficacy

Novel methods to improve the anticancer performance of 5-fluorouracil (5-FU) is quite necessary for clinical medicines. In the present work, we fabricated a novel type of mesoporous silica nanoparticles (MSNs)-based inorganic/organic hybrid nanoparticles covalently attached with poly(oligo(ethylene glycol) monomethyl ether methacrylate) (POEGMA) for improved stabilization and targeting peptide (RGD) for targeted delivery with the aim of improving the anticancer performance of 5-FU. Atom transfer radical polymerization (ATRP) initiator functionalized MSN (MSN-Br) was synthesized at first, which was followed by surface-initiated ATRP of water soluble OEGMA and carboxyl-containing monomer (2-succinyloxyethyl methacrylate, SEMA). Functionalization of RGD onto the hydrophilic P(OEGMA-co-SEMA) chains afforded the final hybrid nanoparticle, MSN-P(OEGMA-co-RGD). 5-FU can be effectively loaded into the meso-pores of MSN-P(OEGMA-co-RGD) (5-FU@MSN-RGD) with drug content ∼7.5wt%. And the dynamic diameter (Dh) and zeta potential (ζ) of 5-FU@MSN-RGD were determined to be 199.3±5.4nm and −8.7±0.5mV, respectively. It was demonstrated that MSN-P(OEGMA-co-RGD) exhibited improved internalization into colon cancer cells and enhanced accumulation in tumor tissues. In addition, compared with free 5-FU, 5-FU@MSN-RGD showed enhanced anticancer efficacy both in vitro and in vivo, implying promising clinical applications.

Mesoporous Silica Nanoparticles with Large Pores for the Encapsulation and Release of Proteins.

Mesoporous silica nanoparticles (MSNs) have been explored extensively as solid supports for proteins in biological and medical applications. Small (<200 nm) MSNs with ordered large pores (>5 nm), capable of encapsulating therapeutic small molecules suitable for delivery applications in vivo, are rare however. Here we present small, elongated, cuboidal, MSNs with average dimensions of 90 × 43 nm that possess disk-shaped cavities, stacked on top of each other, which run parallel to the short axis of the particle. Amine functionalization was achieved by modifying the MSN surface with 3-aminopropyltriethoxysilane or 3-[2-(2-aminoethylamino)ethylamino]propyltrimethoxysilane (AP-MSNs and AEP-MSNs) and were shown to have similar dimensions to the nonfunctionalized MSNs. The dimensions of these particles, and their large surface areas as measured by nitrogen adsorption-desorption isotherms, make them ideal scaffolds for protein encapsulation and delivery. We therefore investigated the encapsulation and release behavior for seven model proteins (α-lactalbumin, ovalbumin, bovine serum albumin, catalase, hemoglobin, lysozyme, and cytochrome c). It was discovered that all types of MSNs used in this study allow rapid encapsulation, with a high loading capacity, for all proteins studied. Furthermore, the release profiles of the proteins were tunable. The variation in both rate and amount of protein uptake and release was found to be determined by the surface chemistry of the MSNs, together with the isoelectric point (pI), and molecular weight of the proteins, as well as by the ionic strength of the buffer. These MSNs with their large surface area and optimal dimensions provide a scaffold with a high encapsulation efficiency and controllable release profiles for a variety of proteins, enabling potential applications in fields such as drug delivery and protein therapy.

A methodology based on the Birnbaum–Saunders distribution for reliability analysis applied to nano-materials

The Birnbaum–Saunders distribution has been widely studied and applied to reliability studies. This paper proposes a novel use of this distribution to analyze the effect on hardness, a material mechanical property, when incorporating nano-particles inside a polymeric bone cement. A plain variety and two modified types of mesoporous silica nano-particles are considered. In biomaterials, one can study the effect of nano-particles on mechanical response reliability. Experimental data collected by the authors from a micro-indentation test about hardness of a commercially available polymeric bone cement are analyzed. Hardness is modeled with the Birnbaum–Saunders distribution and Bayesian inference is performed to derive a methodology, which allows us to evaluate the effect of using nano-particles at different loadings by the R software.

Mesoporous Silica Materials in Drug Delivery System: pH/Glutathione- Responsive Release of Poorly Water-Soluble Pro-drug Quercetin from Two and Three-dimensional Pore-Structure Nanoparticles

Quercetin (Quer) is one of natural products (pro-drugs), presenting pharmacological properties such as: anti-oxidant, anti-inflammatory and anti-cancer activities. However, poor solubility of the Quer causes its poor bioavailability, and consequently reduces its therapeutic efficiency. To manage this problem, different actions are undertaken, among other drug delivery systems (DDSs) are investigated. The objective of present work was to evaluate potential applications of silica nanoparticles as quercetin nanocarriers and to investigate the influence of pH conditions and glutathione (GSH, as non-redox process) concentrations on quercetin release. Two types of mesoporous silica nanoparticles: MCM-41 (2D arrangement of pores) and KCC-1 (3D arrangement of pores) were synthesized and then functionalized by amino-groups. Immersion-evaporation method was used to load the Quer in nanoparticles. Several analysis techniques were used (e.g. electron microscopy, X-Ray diffraction, Zeta potential, simultaneous thermal analysis-connected to FTIR and many more). Obtained results indicated that both types of silica nanoparticles were successfully loaded with quercetin, and that the Quer present in silica mesopores had a non-crystalline structure. Loading capacity of functionalized MCM-41 was slightly higher than functionalized KCC-1 (29.11 wt% and 26.49 wt%, respectively). This difference could be attributed to the differences in the morphology structures such as surface area and pore volume property. From in vitro release and kinetics studies, the results showed that quercetin release from both materials was pH-GSH-silica type nanoparticles-dependent. In summary, it can be stated that pH/GSH-stimuli release of quercetin was achieved using MCM-41 and KCC-1 amine-functionalized mesoporous silica nanoparticles as a drug carriers. Therefore both investigated nanomaterials could be beneficial for long-term release

PH-controlled Release System for Curcumin based on Functionalized Dendritic Mesoporous Silica Nanoparticles

Mesoporous silica materials are promising drug delivery systems, especially in case of poorly water-soluble drugs. Curcumin (Cur) has proven effective for several pharmacological activities including anti-inflammatory, antioxidant, antimicropeal, hepatoprotective, and anticancer activities. In the present work two types of mesoporous silica nanoparticles were evaluated as a Cur carrier for controlled release of this anticancer natural pro-drug: MCM-41 (Two Dimensional) and KCC-1 (Three Dimensional), both functionalized with aminopropyl groups. KCC-NH2 and MCM-NH2 contained a similar amount of Cur (24.5% and 23.9%, respectively). In vitro experiments have shown that both materials effectively release Cur and the cumulative release was enhanced for low acidity (pH=2.5). At low acidic pH (2.5), the KCC-1 sample released higher amount (up to 19%) of curcumin compared to MCM-41 (14%). Thus it is possible to achieve controlled, long-term and effective pH-stimulated release of curcumin from aminefunctionalized mesoporous silica nanoparticles. This finding opens the way for their application for controlled curcumin delivery in cancer disease because of the acidic tumor environment, increase its stability and lead to an increase of the Cur bioavailability. Moreover, the KCC-1 three dimensional mesoporous silica seems to be a more promising nanocarrier compared to the commonly used MCM-41 material.

Biodistribution, excretion, and toxicity of mesoporous silica nanoparticles after oral administration depend on their shape

Mesoporous silica nanoparticles (MSNs) have been proven to be effective drug carriers for oral delivery. However, little attention has been paid to their in vivo biodistribution and toxicity after oral administration. The effect of particle shape on their in vivo behavior is also unknown. In this study, we systematically studied the acute toxicity and biodistribution of three types of MSNs with aspect ratios (ARs) of 1, 1.75 and 5 after oral administration. The effect of particle shape as a key physicochemical parameter of MSNs was discussed. With the increase of AR, MSNs showed decreased in vivo biodegradation, systematic absorption and excretion, especially decreased liver distribution and urinal excretion. During the period of urinal excretion, MSNs induced a shape-dependent renal damage including hemorrhage, vascular congestion and renal tubular necrosis. These findings will enrich the knowledge to rationally engineer bionanomaterials, and bring new insights into nanotoxicity. From the Clinical EditorAdvances in nanotechnology have resulted in improvement in drug delivery, of which mesoporous silica nanoparticles have been used as carriers for oral drugs. Nonetheless, studies on their absorption, distribution, metabolism, excretion (ADME) and toxicity still need to be performed. In this article, authors evaluated the effects of particle size and shape on in vivo behavior. The findings would shine light on future design of future drug delivery systems.

Mesoporous silica nanorods intrinsically doped with photosensitizers as a multifunctional drug carrier for combination therapy of cancer

Mesoporous silica nanoparticles (MSNs) have attracted tremendous attention in recent years as drug delivery carriers due to their large surface areas, tunable sizes, facile modification and considerable biocompatibility. In this work, we fabricate an interesting type of MSNs which are intrinsically doped with photosensitizing molecules, chlorin e6 (Ce6). By increasing the amount of Ce6 doped inside the silica matrix, it is found that the morphology of MSNs changes from spheres to rod-like shapes. The obtained Ce6-doped mesoporous silica nanorods (CMSNRs) are not only able to produce singlet oxygen for photodynamic therapy, but can also serve as a drug delivery platform with high drug loading capacity by utilizing their mesoporous structure. Compared to spherical nanoparticles, it is found that CMSNRs with a larger aspect ratio show much faster uptake by cancer cells. With doxorubicin (DOX) employed as a model drug, the combined photodynamic and chemotherapy is carried out, achieving synergistic anti-tumor effects both in vitro and in vivo. Our study presents a new design of an MSN-based drug delivery platform, which intrinsically is fluorescent and able to serve as a photodynamic agent, promising for future imaging-guided combination therapy of cancer.

Multiscale characterization of acrylic bone cement modified with functionalized mesoporous silica nanoparticles

Acrylic bone cement is widely used to anchor orthopedic implants to bone and mechanical failure of the cement mantle surrounding an implant can contribute to aseptic loosening. In an effort to enhance the mechanical properties of bone cement, a variety of nanoparticles and fibers can be incorporated into the cement matrix. Mesoporous silica nanoparticles (MSNs) are a class of particles that display high potential for use as reinforcement within bone cement. Therefore, the purpose of this study was to quantify the impact of modifying an acrylic cement with various low-loadings of mesoporous silica. Three types of MSNs (one plain variety and two modified with functional groups) at two loading ratios (0.1 and 0.2wt/wt) were incorporated into a commercially available bone cement. The mechanical properties were characterized using four-point bending, microindentation and nanoindentation (static, stress relaxation, and creep) while material properties were assessed through dynamic mechanical analysis, differential scanning calorimetry, thermogravimetric analysis, FTIR spectroscopy, and scanning electron microscopy. Four-point flexural testing and nanoindentation revealed minimal impact on the properties of the cements, except for several changes in the nano-level static mechanical properties. Conversely, microindentation testing demonstrated that the addition of MSNs significantly increased the microhardness. The stress relaxation and creep properties of the cements measured with nanoindentation displayed no effect resulting from the addition of MSNs. The measured material properties were consistent among all cements. Analysis of scanning electron micrographs images revealed that surface functionalization enhanced particle dispersion within the cement matrix and resulted in fewer particle agglomerates. These results suggest that the loading ratios of mesoporous silica used in this study were not an effective reinforcement material. Future work should be conducted to determine the impact of higher MSN loading ratios and alternative functional groups.

Controlled etching of internal and external structures of SiO2 nanoparticles using hydrogen bond of polyelectrolytes.

We have demonstrated a novel strategy for the synthesis of mesoporous silica nanoparticles (MSNPs) using a surfactant-free method under ambient conditions. By the simple addition of an amine-based polymer (polyethylenimine; PEI) with a high molecular weight to a silica nanoparticle (SNP) solution, two types of MSNPs, including rambutan-like MSNPs (R-MSNPs) and hollow MSNPs (H-MSNPs), were produced. The structural changes of the MSNPs were systematically studied using various reaction conditions (reaction time, molar ratio and molecular weight of PEI, etc.) and were observed using electron microscopic techniques. The formation mechanisms of both MSNPs were carefully investigated using XPS, Raman, and IR spectroscopies. Because the synthesized MSNPs are highly porous materials that contain internal organic/inorganic networks, we investigated the removal/adsorption properties of these MSNPs with respect to pollutants toward possible future use in environmental remediation applications. The H-MSNPs exhibited better environmental remediation capabilities relative to the R-MSNPs because PEI is present between the cobweb-like internal structures of the H-MSNPs, thereby providing a significant number of reaction sites for the adsorption of pollutants. The approach presented here can also be used as a direct method for the preparation of intraconnected networks within the substructures.

Re-examining the Size/Charge Paradigm: Differing in Vivo Characteristics of Size- and Charge-Matched Mesoporous Silica Nanoparticles

The combination of nanoparticle (NP) size, charge, and surface chemistry (e.g., extent of modification with polyethylene glycol (PEG)) is accepted as a key determinant of NP/cellular interactions. However, the influence of spatial arrangement and accessibility of the charged molecules on the NP surface vis-à-vis the average surface charge (zeta (ζ) potential) is incompletely understood. Here we demonstrate that two types of mesoporous silica nanoparticles (MSNP) that are matched in terms of primary and hydrodynamic particle size, shape, pore structure, colloidal stability, and ζ potential, but differ in surface chemistry, viz. the spatial arrangement and relative exposure of surface amines, have profoundly different interactions with cells and tissues when evaluated in vitro and in vivo. While both particles are ∼50 nm in diameter, PEGylated, and positively charged (ζ = +40 mV), PEG-PEI (MSNPs modified with exposed polyamines), but not PEG-NMe3(+) (MSNP modified with distributed, obstructed amines) rapidly bind serum proteins, diverse cells types in vitro, and endothelial and white blood cells in vivo (ex ovo chick embryo model). This finding helps elucidate the relative role of surface exposure of charged molecules vs ζ potential in otherwise physicochemically matched MSNP and highlights protein corona neutrality as an important design consideration when synthesizing cationic NPs for biological applications.

Biocompatibility of Mesoporous Silica Nanoparticles

In this review, recent reports on the biocompatibility of mesoporous silica nanoparticles (MSNs) are reviewed, with special emphasis being paid to the correlations between MSNs' structural and compositional features and their biological effects on various cells and tissues. First, the different synthetic routes used to produce the most common types of MSNs and the various methods employed to functionalize their surfaces are discussed. This is, however, done only briefly because of the focus of the review being the biocompatibility of the materials. Similarly, the biological applications of MSNs in areas such as drug and gene delivery, biocatalysis, bioimaging, and biosensing are briefly introduced. Many examples have also been mentioned about the biological applications of MSNs while discussing the materials' biocompatibility. The cytotoxicity of different types of MSNs and the effects of their various structural characteristics on their biological activities, which are the focus of this review, are then described in detail. In addition, synthetic strategies developed to reduce or eliminate any possible negative biological effects associated with MSNs or to improve their biocompatibility, as necessary, are illustrated. At the same time, recent reports on the interactions between MSNs and various in vivo or in vitro biological systems, plus our opinions and remarks on what the future may hold for this field, are included.

A new fluoride mediated synthesis of mesoporous silica and their usefulness in controlled delivery of duloxetine hydrochloride a serotonin re-uptake inhibitor

A new type of mesoporous silica nanoparticle (MSN) was synthesized in fluoride media via sol–gel technique using TritonX 100 and Tween-20. The surface area and pore volume of the MSN particles were modified by varying the concentration of Tween-20. The prepared MSN nanoparticles with large surface area and pore volume (T-2, T-3) were selected to accommodate the model drug duloxetine hydrochloride (DX) for evaluation of their drug-loading and release abilities. Calcined and DX loaded nanoparticles were characterized by Brunauer–Emmett–Teller technique (BET), powder X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric (TG) analysis and UV-diffuse reflectance (UV-DRS). In vitro release studies proved that the particle displays an initial burst release followed by sustained release for up to 140h. From the studies it is evident that the synthesized particle may be useful as a carrier for sustained release of active pharmaceutical ingredients (APIs).

Measurement of Uptake and Release Capacities of Mesoporous Silica Nanoparticles Enabled by Nanovalve Gates

The uptake and release capacities of mesoporous silica particles are measured on nanovalve-gated stimulated release systems, using a water soluble biological stain, Hoechst 33342, as the cargo model. Five different types of mesoporous silica nanoparticles: 2D-hexagonal MCM-41, swollen pore MCM-41, rod-like MCM-41, hollow mesoporous nanoparticles and radial mesoporous nanoparticles are studied and compared. Solid silica nanoparticles are used as the control. Because of the presence of the nanovalves, the loaded and capped particles can be washed thoroughly without losing the content of the mesopores. The quantity of Hoechst 33342 molecules trapped within the nanoparticles and released upon opening the nanovalves are systematically studied for the first time. The loading conditions are optimized by varying the Hoechst concentration in the loading solutions. Surprisingly, increasing the Hoechst concentration in the loading solution does not always result in a larger amount of Hoechst being trapped and released. Among the five types of mesoporous silica nanoparticles, the radial mesoporous nanoparticles and the swollen pore MCM-41 particles show the highest and lowest release capacity, respectively. The uptake capacities is correlated with the specific surface area of the materials rather than their internal volume. The uptake and release behaviors are also affected by charge and spatial factors.

Adsorption and Desorption Behaviors of DNA with Magnetic Mesoporous Silica Nanoparticles

The interaction between DNA and mesopores is one of the basic concerns when mesoporous silica nanoparticle (MSN) is used as a DNA carrier. In this work, we have synthesized a type of mesoporous silica nanoparticle that has a Fe(3)O(4) inner core and mesoporous silica shell. This magnetic mesoporous silica nanoparticle (denoted as M-MSN) offers us a convenient platform to manipulate the DNA adsorption and desorption processes as it can be easily separated from solution by applying a magnetic field. The DNA adsorption behavior is studied as a function of time in chaotropic salt solution. The maximum amount of adsorbed DNA is determined as high as 121.6 mg/g. We have also developed a method to separate the DNA adsorbed onto the external surface and into the mesopores by simply changing temperature windows. The desorption results suggest that, within the whole adsorbed DNA molecules, about 89.5% has been taken up by M-MSN mesopores. Through the dynamic light scattering experiment, we have found that the hydrodynamic size for M-MSN with DNA in its mesopores is higher than the naked M-MSN. Finally, the preliminary result of the adsorption mechanism study suggests that the DNA adsorption into mesopores may generate more intermolecular hydrogen bonds than those formed on the external surface.

Keep the red stuff in

Contrary to many silica materials, certain types of mesoporous silica nanoparticles do not rupture red blood cells easily