Types Of Mesoporous Silica Nanoparticles Research Articles

In vivo treatment of zinc phosphide poisoning by administration of mesoporous silica nanoparticles as an effective antidote agent

Mesoporous silica nanoparticles (MSNs) are highly advanced engineered particles with increased surface area and extreme adsorption capacity for various molecules. Herein, two types of MSNs were synthesized and applied as adsorbents for phosphine gas. One was without functional groups (MSN), and the other was post-modified with boric acid (MSN-BA). The structures of MSN and boric acid-modified MSN with high surface areas of about 1025 and 650 m2/g, respectively, were defined. MSN was found to have particles with sizes around 30 nm by transmission electron microscopy (TEM). In the present study, MSNs were used as an antidote to phosphorus poisoning, and zinc phosphide (phosphorus) powder was used as the toxic and lethal agent. In vivo analysis was carried out on rats to demonstrate the ability of MSNs to chemisorb phosphine gas. In the survival percentage assessment, Phos-poisoned animals were kept alive after treatment with MSNs, and the MSN-BA-treated group (dose of 5 mg/kg) was shown to have a 60 % survival rate. Blood serum analysis showed that MSNs have a high potential to alleviate organ blood damage, and serum biomarkers dropped sharply while phosphine-poisoned animals were treated with MSN-BA.

Antibiofilm activity of mesoporous silica nanoparticles against the biofilm associated infections.

In pharmaceutical industries, various chemical carriers are present which are used for drug delivery to the correct target sites. The most popular and upcoming drug delivery carriers are mesoporous silica nanoparticles (MSN). The main reason for its popularity is its ability to be specific and optimize the drug delivery process in a controlled manner. Nowadays, MSNs are widely used to eradicate various microbial infections, especially the ones related to biofilms. Biofilms are sessile groups of cells that live by forming a consortium and exhibit antibacterial resistance (AMR). They exhibit AMR by extracellular polymeric substances (EPS) and various quorum sensing (QS) signaling molecules. Usually, bacterial and fungal cells are capable of forming biofilms. These biofilms are pathogenic. In the majority of the cases, biofilms cause nosocomial diseases. This review will focus on the antibiofilm activities of MSN, its mechanism of target-specific drug delivery, and its ability to disrupt the bacterial biofilms inhibiting the infection. The review will also discuss various mechanisms for the delivery of pharmaceutical molecules by the MSNs to inhibit the bacterial biofilms, and lastly, we will talk about the different types of MSNs and their antibiofilm activities.

Evaluating thermogravimetric analysis for the measurement of drug loading in mesoporous silica nanoparticles (MSNs)

In this study, a thermogravimetric analysis (TGA) method for measuring the drug loading in mesoporous silica nanoparticles (MSNs) has been developed and evaluated in comparison with the drug loading quantification by high-performance liquid chromatography (HPLC). Indapamide was loaded into two different types of MSNs, namely Mobile Crystalline Material (MCM-41, pore size = 1.2 nm) and Santa Barbara Amorphous (SBA-15, pore size = 4.1 nm). Physical mixtures of the drug and silica gave a linear correlation between the observed and expected drug content for both TGA and HPLC, which were used for calibration purposes. The limit of detection (LOD) for the TGA method obtained from the physical mixture calibration curve was 0.77 % (w/w) and the r2 value was 0.9936, whereas the HPLC had a LOD of 0.06 % (w/w) and an r2 value of 0.9933. The sensitivity of the TGA method was well established using the drug loading studies, as it can detect the low loading of MCM-41 at 2.2 ± 0.21 % (w/w), compared to 5.1 ± 0.12 % (w/w) with the SBA-15. In all samples applied, the multiple comparison analysis showed an insignificant difference between the two methods (p > 0.05). The TGA data presented good evidence for using this technique as a sensitive, cost-effective, and low-variable quantitative analysis in the drug loading determination of the MSNs. TGA is not a selective method of quantification, but optimising the method using the pure and blank samples of MSNs and drug can significantly improve the sensitivity. This work provides a unique approach to apply TGA as a selective and more favourable method to characterise MSNs to do early formulation developments.

Composite Mesoporous Silica Nanoparticles with Dual-color Afterglow for Cross-correlation-based Living Cell Imaging.

Room temperature phosphorescence (RTP) materials are characterized with emission after removing the excitation source. Such long-lived emission feature possesses great potential in biological fluorescence imaging because it enables a way regarding temporal dimension for separating the interference of autofluorescence and common noises typically encountered in conventional fluorescence imaging. Herein, we constructed a new type of mesoporous silica nanoparticles (MSNs)-based composite nanoparticles (NPs) with dual-color long-lived emission, namely millisecond-level green phosphorescence and sub-millisecond-level delayed red fluorescence by encapsulating a typical RTP dye and Rhodamine dye in the cavities of the MSNs with the former acting as energy donor (D) while the latter as acceptor (A). Benefiting from the close D-A proximity, energy match between the donor and the acceptor and the optimized D/A ratio in the composite NPs, efficient triplet-to-singlet Förster resonance energy transfer (TS-FRET) in the NPs occurred upon exciting the donor, which enabled dual-color long-lived emission. The preliminary results of dual-color correlation imaging of live cells based on such emission feature unequivocally verified the unique ability of such NPs for distinguishing the false positive generated by common emitters with single-color emission feature.

Pickering Emulsions Stabilized by Mesoporous Nanoparticles with Different Morphologies in Combination with DTAB.

The morphology of nanoparticles plays a significant role in the properties and applications of Pickering emulsions. Oil-in-water (O/W) Pickering emulsions were prepared using spherical, rod-like, and thread-like mesoporous silica nanoparticles (MSNPs) in combination with the cationic surfactant dodecyltrimethylammonium bromide (DTAB) as a stabilizer. The effects of nanoparticle morphology on the stability and stimuli-responsive properties of Pickering emulsions were investigated. For spherical and rod-like MSNP systems, stable Pickering emulsions were obtained at DTAB concentrations above 0.2 mmol·L–1. Stable Pickering emulsions containing thread-like MSNPs were produced at lower DTAB concentrations of approximately 0.1 mmol·L–1. The droplets with thread-like MSNPs were extremely large with an average diameter around 700 μm at DTAB concentrations of 0.1–0.3 mmol·L–1, which were approximately 20 times larger than those of conventional droplets. Scanning electron microscopy (SEM) images showed that all three types of MSNPs were located at the O/W interfaces. Irrespective of the morphology of the MSNPs, all the stable Pickering emulsions retained their original appearance for more than 6 months. By adding NaOH and HCl alternatively, the Pickering emulsions containing spherical and rod-like MSNPs could be switched between unstable and stable states more than 60 times. The Pickering emulsions containing thread-like MSNPs, by contrast, could have their droplet size switched between large and small more than 10 times without any obvious phase separation. The high anisotropy of thread-like MSNPs contributed to the low interface curvature of the droplets. This study revealed the relationship between the morphology of MSNPs and the characteristics of Pickering emulsions. These results enrich our knowledge about the formulation of Pickering emulsions and expand their applications.

Effect of Surface Functionalization and Pore Structure Type on the Release Performance of Mesoporous Silica Nanoparticles

Based on the excellent physicochemical properties of mesoporous silica nanoparticles (MSN), the application of MSN in drug delivery has become a popular strategy. However, a wide variety of MSN structures and surface modification affect the drug loading and release, thus affecting the effectiveness of drug delivery system. Therefore, the effects of MSN type, pore structure and modified functional groups on drug release properties were investigated in this paper. A series of MSN was synthesized by sol-gel method, and the mesopore type and pore size were adjusted. Their surfaces were modified by amino groups (NH 2 ) and polydopamine (PDA) to change the surface charge. Anticancer Doxorubicin (DOX) was used as a model drug to study effects of different types of MSN on drug loading and release. MSN with hollow structure had a large inner cavity for DOX loading and tiny pore shell to prevent DOX loss, leading to higher loading capacity. MSN with surface-modified amine was positively charged and processed good pH responsiveness and accelerated DOX release. Thus hexagonal pore MSN-NH 2 and MSN-PDA were the anticancer DOX delivery carriers with better combined release performance in terms of pH-responsive performance and sustained release effect. Finally, several kinetic models were measured to fit the in vitro DOX release data and the results showed that release behaviors of different MSNs were more consistent with Korsmeyer-Peppas release kinetic model. All of them were Fick diffusion-controlled except for the second release stage of hollow MSN at pH 7.4, which was non-Fick diffusion release. • A series of MSNs with diverse structures and modification were studied. • Specific surface area, pore volume/type and surface charge affected drug loading. • Diverse kinetic models were employed to investigate mechanism of drug release. • MSNs with modification were drug delivery systems with better release performance.

How Advancing are Mesoporous Silica Nanoparticles? A Comprehensive Review of the Literature.

The application of mesoporous silica nanoparticles (MSNs) is ubiquitous in various sciences. MSNs possess unique features, including the diversity in manufacturing by different synthesis methods and from different sources, structure controllability, pore design capabilities, pore size tunability, nanoparticle size distribution adjustment, and the ability to create diverse functional groups on their surface. These characteristics have led to various types of MSNs as a unique system for drug delivery. In this review, first, the synthesis of MSNs by different methods via using different sources were studied. Then, the parameters affecting their physicochemical properties and functionalization have been discussed. Finally, the last decade’s novel strategies, including surface functionalization, drug delivery, and cancer treatment, based on the MSNs in drug delivery and cancer therapy have been addressed.

New radiation therapy for cancer using monochromatic X-rays and nanoparticles

There are longstanding research efforts to improve treatments for cancers. Two treatment options are chemotherapy and radiation therapy but there is room for improvement and researchers at the Institute for Advanced Study, Kyoto University, Japan, have developed a new method that could lead to the development of a new type of cancer radiation therapy and save lives. The research team is led by Professor Fuyuhiko Tamanoi who is principal investigator at the Tamanoi Laboratory at Kyoto University and leader of the Quantum Nano Medicine Research Center. The method involves generating a cloud of electrons inside a cancer cell that causes DNA breaks, which has potential to eliminate cancer cells. This approach is built on the Auger effect which postulates that when high Z elements are irradiated with monochromatic X-rays, the energy from the X-rays are absorbed by the K-shell electron, which leads to the release of multiple electrons, which have the capability to produce DNA double strand breaks. To achieve the necessary conditions, the team used nanoparticle design combined with state-of-the-art X-ray technology. The team is also developing a new type of nanoparticle called Biodegradable periodic mesoporous organosilica (BPMO), which is a type of mesoporous silica nanoparticles (MSN).

Understanding the Effect of Functionalization on Loading Capacity and Release of Drug from Mesoporous Silica Nanoparticles: A Computationally Driven Study.

MCM-41, a type of mesoporous silica nanoparticle, has garnered widespread interests as a useful carrier for drug delivery wherein the drug gets adsorbed into the pores of the carrier. To understand the adsorption mechanism and release of the drug at the molecular level, in the current study, it was attempted to generate a computational model for the loading of 5-fluorouracil (5-FU), a chemotherapeutic agent into surface-modified MCM-41. The molecular surface models of the mesoporous silica (MCM-41) nanoparticle with different surface substitutions were created. In the first stage, molecular mechanics (MM) simulations were carried out to obtain the optimized surface structures. Subsequently, a 5-FU drug molecule in its different forms was docked on top of different MCM-41 surfaces to understand the adsorption orientation and energetics. To further validate the results, more accurate quantum mechanical (QM) calculations were also carried out, and the energetics between the QM and MM calculations are found to be similar. All the substitutions (−NH2, −CN, −COOH) except the methyl substitution exhibited favorable interactions compared to the unsubstituted MCM-41 surface which was in accordance with the experimental observations. The release rate of 5-FU from MCM-41 and aminopropyl-substituted MCM-41 (MCM-NH2) was studied using molecular dynamics simulations which revealed that the release rate of 5-FU from the MCM-NH2 surface was slower compared to that of plain MCM-41. The detailed surface characteristics and the adsorption energies from the molecular simulations correlating the loading capacity and release are reported in here.

Mesoporous silica nanoparticles: Synthesis, functionalization, drug loading and release - A review


 
 
 
 A brief survey on the synthesis of several types of mesoporous silica nanoparticles and their uses as drug delivery nanocarriers is presented in this study. Mesoporous silica nanoparticles (MSNs) have a small pore size, resulting in a large surface area and porosity. These characteristics are easily adjustable, conferring on MSNs advantages over other nanoparticles for use in medicine and pharmacy. Previous and latest trends in the technology of this type of nanoparticles, and the possibilities for their application in drug loading are considered, as well as methods for increasing drug loading capacity, functionalization and release of bioactive substances. It has been found that the method used for the synthesis of some types of MSNs results in better drug loading. The functionalization of nanoparticles not only allows for more successful loading of bioactive substances in its pores, it also successfully controls drug release. Moreover, these versatile nanoparticles enhance the solubility of poorly-soluble drugs, thereby overcoming one of the biggest problems in the absorption of these drugs.
 
 
 

Theranostic mesoporous silica nanoparticles made of multi-nuclear gold or carbon quantum dots particles serving as pH responsive drug delivery system

Mesoporous silica nanoparticles are promising candidates to deliver proteins, antibodies, and anticancer drugs and to be served as an adsorbent of various types of substrate. Herein, a theranostic approach, in the preparation of fluorescence-type mesoporous silica for pH-responsive delivery of anticancer drug, doxorubicin, is introduced. By this mean, three types of mesoporous silica were synthesized. The ordinary type of mesoporous silica nanoparticles containing propylamine functional groups was synthesized by a controlled-size technique. Two types of fluorescence mesoporous silica were prepared, doped with gold or quantum dots nanoparticles. The fluorescence imaging has shown that the optical properties of the gold or carbon quantum dots have been transferred to the mesoporous matrix in doping processes. The as-prepared mesoporous materials were conjugated to doxorubicin via Schiff-base linkage. Several characterization techniques were utilized to detect the structure of the particles including FT-IR spectroscopy, XRD, N 2 adsorption/desorption, transition, and scanning electron microscopy. The amount of conjugated doxorubicin was analyzed by UV–Vis spectroscopy. The pH-responsive character was proved assessing the release profile in different pH ranges including physiological pH. The safety of the particles was evaluated by cell cytotoxicity assay on breast cancer cell line, MCF-7. As-prepared particles showed no cytotoxic behavior, but when they were loaded by doxorubicin, the appreciable release of the drug and subsequent cytotoxicity resulted against MCF-7 cells. The hemolytic study was conducted to prove the biocompatibility of these particles in the blood. Altogether, the proposed materials are suitable to be considered as safe and to be used as a theranostic platform for therapeutic and imaging purposes. • Three types of MSN were prepared and applied for drug delivery. • The fluorophore MSNs of GNP@MSN and QCD@MSN were organized for theranostic purpose. • DOX was conjugated to MSNs, and released through pH responsive profile. • The fluorophore MSNs showed biocompatibility and fluorescent contrast in MCF-7 cells. • MSNs@DOX showed toxicity in parallel and even higher than of free DOX in MCF-7 cell.

Multiple Roles of Mesoporous Silica in Safe Pesticide Application by Nanotechnology: A Review.

Pollution related to pesticides has become a global problem due to their low utilization and non-targeting application, and nanotechnology has shown great potential in promoting sustainable agriculture. Nowadays, mesoporous silica-based nanomaterials have garnered immense attention for improving the efficacy and safety of pesticides due to their distinctive advantages of low toxicity, high thermal and chemical stability, and particularly size tunability and versatile functionality. Based on the introduction of the structure and synthesis of different types of mesoporous silica nanoparticles (MSNs), the multiple roles of mesoporous silica in safe pesticide application using nanotechnology are discussed in this Review: (i) as nanocarrier for sustained/controlled delivery of pesticides, (ii) as adsorbent for enrichment or removal of pesticides in aqueous media, (iii) as support of catalysts for degradation of pesticide contaminants, and (iv) as support of sensors for detection of pesticides. Several scientific issues, strategies, and mechanisms regarding the application of MSNs in the pesticide field are presented, with their future directions discussed in terms of their environmental risk assessment, in-depth mechanism exploration, and cost-benefit consideration for their continuous development. This Review will provide critical information to related researchers and may open up their minds to develop new advances in pesticide application.

Multimodal Mesoporous Silica Nanocarriers for Dual Stimuli-Responsive Drug Release and Excellent Photothermal Ablation of Cancer Cells.

BackgroundCore-shell types of mesoporous silica nanoparticles (MSNs) with multimodal functionalities were developed for bio-imaging, controlled drug release associated with external pH, and near-infrared radiation (NIR) stimuli, and targeted and effective chemo-photothermal therapeutics.Materials and MethodsWe synthesized and developed a core-shell type of mesoporous silica nanocarriers for fluorescent imaging, stimuli-responsive drug release, magnetic separation, antibody targeting, and chemo-photothermal therapeutics. Also, the biocompatibility, cellular uptake, cytotoxicity, and photothermal therapy on these FS3-based nanocarriers were systematically investigated.ResultsMagnetic mesoporous silica nanoparticles was prepared by coating a Fe3O4 core with a mesoporous silica shell, followed by grafting with fluorescent conjugates, so-called FS3. The resulting FM3 was preloaded with therapeutic cisplatin and coated with polydopamine layer, so-called FS3P/C. Eventually, graphene oxide-wrapped FS3P/C (FS3P-G/C) exhibited high sensitivity in the dual stimuli (pH, NIR)-responsive controlled release behavior. On the other hand, Au NPs-coated FS3P/C (FS3P-A/C) exhibited more stable release behavior, irrespective of pH changes, and exhibited much more enhanced release rate under the same NIR irradiation. Notably, FS3P-A/C showed strong NIR absorption, enabling photothermal destruction of HeLa cells by its chemo-photothermal therapeutic effects under NIR irradiation (808 nm, 1.5 W/cm2). The selective uptake of FS3-based nanocarriers was confirmed in cancer cell lines including HeLa (American Type Culture Collection - ATCC) and SHSY5Y (ATCC 2266) by the images obtained from confocal laser scanning microscopy, flow cytometry, and transmission electron microscopy instruments. Cisplatin-free FS3-based nanocarriers revealed good cellular uptake and low cytotoxicity against cancerous HeLa and SH-SY5Y cells, but showed no obvious toxicity to normal HEK293 (ATCC 1573) cell.ConclusionAlong with the facile synthesis of FS3-based nanocarriers, the integration of all these strategies into one single unit will be a prospective candidate for biomedical applications, especially in chemo-photothermal therapeutics, targeted delivery, and stimuli-responsive controlled drug release against multiple cancer cell types.

An optimized mesoporous silica nanosphere-based carrier system with chemically removable Au nanoparticle caps for redox-stimulated and targeted drug delivery

To date, numerous drug delivery systems based on mesoporous silica nanoparticles (MSNs) have been explored, but little has been done on optimizing the structure and composition of MSNs to achieve effective drug delivery for cancer cells. Ideal mesoporous drug carriers should incorporate drugs in a way that prevents pre-release in biological surroundings before reaching the targeted area, which usually requires the capping of the open ends on the surface and the incorporation of targeting ligands on the exterior of nanocarriers. In this study, an MSN-based drug carrier system was synthesized with biocompatible Au nanoparticles (NPs) as the ‘hard caps’, and folic acid conjugated to the surface for targeting folate receptor-overexpressed cancer cells. Disulfide bonds linking Au and MSN NPs were introduced to the MSN surface as the redox-sensitive and chemically removable components. To study the effect of structures of MSNs in drug release, three types of MSNs were compared, including hollow mesoporous silica NPs, large-pore hollow mesoporous silica NPs and typical nano-sized pores on the surface (MSN). To achieve optimal coverage of thiol groups, two methods of functionalization were compared in effecting drug loading and release in vitro. Finally, the effect of residual surfactant was also discussed in anticancer studies. Therefore, the appropriate MSN nanostructure for redox-sensitive and targeted drug delivery was optimized.

Tannic acid-templated mesoporous silica nanoparticles as an effective treatment in acute ferrous sulfate poisoning

In the present study, four types of Mesoporous Silica Nanoparticles (MSNs) were synthesized by two different synthesis methods using Cetyltrimethylammonium bromide (CTAB) or tannic acid as templating agents. Two of the 4 types of synthesized MSNs were functionalized with an amine group whereas the other two remained non-functionalized. Structure and functional groups of the MSNs were determined by Fourier-transform infrared (FT-IR) spectrometry, elemental analysis (CHN) and Thermogravimetric analysis (TGA). In addition to the evaluation of morphological aspects using transmission electron microscopy (TEM), the hydrodynamic dimensions of the MSNs were also evaluated by dynamic light scattering (DLS). The MSNs were monodispersed and spherical in shape, with approximate size of 100–260 nm. The pore sizes of the nanoparticles ranged from 4 to 5.5 nm, and the surface areas were around 370–740 m2/g. In the initial phase, the in vitro adsorption capacity of the synthesized nanoparticles for ferrous sulfate was assessed. Subsequently, the most effective nanoparticle, tannic acid-templated MSNs with amine group (TA-MSN-NH2), with the maximum adsorption capacity (29.06 (mg/g)) was selected for further in vivo study. In vivo analysis showed that 1 g/kg of TA-MSN-NH2 could be utilized to promote the adsorption of iron in acute oral toxicity with 100 mg/kg of ferrous sulfate.

Amino-Functionalized Mesoporous Silica Nanoparticle-Encapsulated Octahedral Organoruthenium Complex as an Efficient Platform for Combatting Cancer.

In the process of synthesis of a new drug, as important as the drug itself is the formulation used, because the same compound can present a very different efficacy depending on how it is administered. In this work, we demonstrate how the antitumor capacity of a new octahedral organoruthenium complex, [Ru(ppy-CHO)(phen)2][PF6] is affected by its encapsulation in different types of mesoporous silica nanoparticles. The interactions between the Ru complex and the silica matrix and how these interactions are affected at two different pHs (7.4 and 5.4, mimicking physiological and endolysosomal acidic conditions, respectively) have been studied. The encapsulation has also been shown to affect the induction of apoptosis and necrosis and progression of the cell cycle compared to the free drug. The encapsulation of the Ru complex in nanoparticles functionalized with amino groups produced very high anticancer activity in cancer cells in vitro, especially against U87 glioblastoma cells, favoring cellular internalization and significantly increasing the anticancer capacity of the initial non-encapsulated Ru complex.

The Influence of Nanoparticle Shape on Protein Corona Formation.

Nanoparticles have become an important utility in many areas of medical treatment such as targeted drug and treatment delivery as well as imaging and diagnostics. These advances require a complete understanding of nanoparticles' fate once placed in the body. Upon exposure to blood, proteins adsorb onto the nanoparticles surface and form a protein corona, which determines the particles' biological fate. This study reports on the protein corona formation from blood serum and plasma on spherical and rod-shaped nanoparticles. These two types of mesoporous silica nanoparticles have identical chemistry, porosity, surface potential, and size in the y-dimension, one being a sphere and the other a rod shape. The results show a significantly larger amount of protein attaching from both plasma and serum on the rod-like particles compared to the spheres. Interrogation of the protein corona by liquid chromatography-mass spectrometry reveals shape-dependent differences in the adsorption of immunoglobulins and albumin proteins from both plasma and serum. This study points to the need for taking nanoparticle shape into consideration because it can have a significant impact on the fate and therapeutic potential of nanoparticles when placed in the body.

Protective properties of mesocellular silica foams against aggregation and enzymatic hydrolysis of loaded proteins for oral protein delivery

Numerous types of mesoporous silica nanoparticles (MSNs) have been studied as carriers for small molecular drugs. However, few reports have been conducted on small MSNs having large pores, and that are suitable for loading and orally delivering therapeutic proteins. In particular, their protective properties against aggregation and enzymatic hydrolysis of loaded proteins have been rarely studied. In this study, mesocellular silica foams (MCFs) with large and different pore sizes were prepared. The loading and release behaviors of three model proteins with different molecular weights were studied. The protective properties of the MCFs against enzymatic hydrolysis of the loaded proteins were tested by sodium dodecyl sulfate polyacrylamide gel electrophoresis and high-performance liquid chromatography. The protecting effects of the MCFs against conformational change and aggregation of the loaded proteins were evaluated by circular dichroism and synchronous fluorescence spectra. Diabetic mice were inducted to evaluate in a preliminary manner the in vivo hypoglycemic effect of insulin loaded MCFs. The prepared MCFs showed rapid and high drug loading (up to 43%) of proteins. The release of proteins was tunable depending on the pore size. The lysozyme loaded MCFs could release 87% intact protein after incubation with pancreatin for 0.5 h. The digestion times for the insulin loaded in MCFs were prolonged to twice that of naked insulin. The secondary conformational changes for the insulin loaded in MCFs were only 1/40 to 1/20 of that of naked insulin incubated with Zn2+. Orally administered insulin-loaded MCF could reduce the blood glucose level to 69%. The prepared MCFs could effectively protect the loaded proteins from aggregation and enzymatic hydrolysis, thus exhibiting potential for application as carriers for protein delivery.

Facile assembly of mesoporous silica nanoparticles with hierarchical pore structure for CO2 capture

In the work, we propose an efficient one-pot approach for synthesis of a new type of mesoporous silica nanoparticles (MSNs). That can be successfully realized by using tetraethylorthosilicate (TEOS) and N-[3-(trimethoxysilyl)propyl]ethylenediamine (TSD) as the silica precursors and cetyltrimethylammonium bromide (CTAB) as the structure-directing agent through a facile assembly process. The as-synthesized MSNs possess a spherical morphology with about 230 nm, a relatively high surface area of 133 m2/g, and a hierarchical pore size distribution. When applied as the sorbents, the amine-functioned MSNs demonstrate the enhanced adsorption capacity for CO2 capture (at 1 bar, 15 vol% CO2, up to 80.5 mg/g at 75 °C), high selectivity, and good cycling durability, benefiting from the suitable modification of polyethyleneimine.

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.