Amine-functionalized Mesoporous Silica Nanoparticles Research Articles

Fast solid-phase extraction of N-linked glycopeptides by amine-functionalized mesoporous silica nanoparticles.

Selective enrichment is a crucial step before the mass spectrometric analysis of glycoproteins. A new approach using 3-aminopropyltriethoxysilane (APTES)-functionalized mesoporous silica materials (SBA-15) was reported to enrich the glycoproteins. Selective extraction of glycopeptides was achieved through coupling the oxidized glycan chains on the glycopeptides with the amine groups on SBA-15 through a reductive amination reaction, then the captured glycopeptides were detached from the SBA-15 for the following MS analysis using the enzyme PNGase F. Because the mesoporous material has a confinement effect, the efficiency of enrichment and enzymatic deglycosylation was improved dramatically. The coupling time was shortened from 4 hours to 1 hour, and the deglycosylation time was greatly shortened from 6 hours to 3 hours. This approach was successfully applied to profile the N-glycoproteome of human colorectal cancer serum. 84 N-linked glycosylation sites from 56 N-linked glycoproteins were identified from as little as 5 μL serum.

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

Biomimetic Intrafibrillar Mineralization of Type I Collagen with Intermediate Precursors-loaded Mesoporous Carriers.

Limited continuous replenishment of the mineralization medium is a restriction for in-situ solution-based remineralization of hypomineralized body tissues. Here, we report a process that generated amine-functionalized mesoporous silica nanoparticles for sustained release of biomimetic analog-stabilized amorphous calcium phosphate precursors. Both two-dimensional and three-dimensional collagen models can be intrafibrillarly mineralized with these released fluidic intermediate precursors. This represents an important advance in the translation of biomineralization concepts into regimes for in-situ remineralization of bone and teeth.

Removal of Lead(II), Copper(II) and Zinc(II) Ions from Aqueous Solutions Using Magnetic Amine-Functionalized Mesoporous Silica Nanocomposites

In this work, a batch adsorption study was conducted to investigate the removal efficiency of lead, copper and zinc ions from aqueous solutions. Magnetic amine-functionalized mesoporous silica nanoparticles were synthesized by grafting amine groups within the channels of magnetic mesoporous silica nanocomposites. Morphological and structural characterizations were made by X-ray powder diffraction, N2 adsorption-desorption, scanning and transmission electron microscopy, Fourier transform infrared spectroscopy and elemental analysis. Among different factors influencing the sorption process, solution pH, shaking time and mass of adsorbent were investigated. The removal efficiencies were higher than 98% under optimized experimental conditions. Maximum adsorption capacities calculated by the Langmuir model were 268, 93 and 82 mg g-1, for lead(II), copper(II) and zinc(II) ions, respectively. Accuracy and applicability of the synthesized adsorbent was estimated by analyzing spiked natural water samples and good recoveries (> 95%) were obtained with no matrix interferences.

Reduction of the oxygen reduction reaction overpotential of nitrogen-doped graphene by designing it to a microspherical hollow shape

Nitrogen-doped hollow graphene microspheres (NHGSs), synthesized through a procedure involving the calcination of graphene–oxide-wrapped amine-functionalized mesoporous silica nanoparticles (AFMSNs) and the subsequent removal of the AFMSNs via HF etching, have been employed as an electrocatalyst for the oxygen reduction reaction (ORR). It has been shown that these NHGSs are highly active toward ORR and exhibit higher electrocatalytic activity than graphene, nitrogen-doped graphene (NG), hollow graphene microspheres (HGSs), and JM Pt/C 40 wt%, and a comparable overpotential to JM Pt/C 40 wt%. Their high electrocatalytic activity could be attributed to the N-doped graphitic structure, which produces more active sites for the ORR, allowing the easier adsorption of oxygen and the subsequent reduction; and the specific microspherical hollow structure, which promotes the exposure of more surface area accessible to electrolytes, thereby allowing an easier diffusion of electrolytes into and out of the electrode catalyst layers. Their low overpotential for the ORR can be attributed to the specific microspherical hollow structure, which reduces the overpotential contribution from the mass transport limitation. The stability measurements show that NHGSs also exhibit a much higher stability than graphene, NG, HGSs, and JM Pt/C 40 wt%, and are immune to the methanol crossover and CO poisoning effects, which all together makes NHGSs highly attractive as an electrocatalyst for the ORR.

Detection of TNT based on conjugated polymer encapsulated in mesoporous silica nanoparticles through FRET

Amine-functionalized mesoporous silica nanoparticles containing poly(p-phenylenevinylene) provide a facile strategy to detect TNT through fluorescence resonance energy transfer (FRET). The observed linear fluorescence intensity change allows the quantitative detection of TNT with the detection limit of 6 × 10(-7) M.

Adsorption and protection of plasmid DNA on mesoporous silica nanoparticles modified with various amounts of organosilane

Ordered MCM-41-type mesoporous silica nanoparticles (MSNs) with pore size of 2.6nm were synthesized and were further modified with various amounts of 3-aminopropyltriethoxysilane (APTES), respectively, by a direct co-condensation method. These amine functionalized mesoporous silica nanoparticles (Am-MSNs) were employed to complex with plasmid DNA (pDNA) to study their adsorption and protection capacities. The results demonstrate the MSNs functionalized with aminopropyl groups present advanced adsorption capacities for pDNA immobilization. And Am-MSNs with high APTES amount lead to high amount of pDNA adsorption. Further investigation of pDNA protection shows that Am-MSNs with moderate APTES amount could completely protect pDNA from enzymatic degradation, while those with smaller and/or higher amount of APTES could partially provide protection of pDNA.

Kinetics of oxidation of an organic amine with a Cr(V) salen complex in homogeneous aqueous solution and on the surface of mesoporous silica

A comparative study of catalytic activity under homogeneous and heterogeneous conditions was carried out using the (salen)Cr(III)-catalyzed oxidation of tetramethylbenzidine (TMB) with iodosobenzene as a model reaction. Amine-functionalized mesoporous silica nanoparticles (MSN) were synthesized in a co-condensation reaction and functionalized with salen via a covalent Si-C bond. A Cr(III) complex of this supported ligand, MSN-(salen)Cr(III), was prepared and characterized. Data from powder XRD, BET isotherms and BJH pore size distribution all showed that MSN-(salen)Cr(III) still had the typical MSN high surface area, narrow pore size distribution, and ordered hexagonal pore structure, which were further confirmed by transmission electron microscopy (TEM) images. (13)C and (29)Si solid-state NMR data provided structural information about the catalyst and verified successful functionalization of the salen ligand and coordination to Cr(III). No unreacted salen or Cr(III) were observed. The loadings of salen and salen-Cr(III) complex were determined via TGA and EDX, respectively. Both measurements indicated that approximately 0.5 mmol/g of catalyst was loaded on the surface of MSN. The oxidation of TMB with iodosobenzene using MSN-(salen)Cr(III) as a heterogeneous catalyst exhibited both similarities and differences with the analogous homogeneous reaction using (salen)Cr(III)(H(2)O)(+) as a catalyst in aqueous acetonitrile. In the presence of 0.10 M HClO(4), the two catalytic reactions proceeded at similar rates and generated the doubly oxidized product TMB(2+). In the absence of acid, the radical cation TMB (+) was produced. The kinetics of the heterogeneous reaction in the absence of added acid responded to concentrations of all three reagents, i.e. (salen)Cr(III), TMB, and PhIO.