And 3-aminopropyltriethoxysilane Research Articles

High-temperature proton exchange membrane with dual proton transfer channels by incorporating phosphonic acid functionalized siloxane into poly(2,6-dimethyl-1,4-phenyleneoxide) (PPO)

A series of high-temperature proton exchange membranes were prepared by incorporating phosphonic acid functionalized siloxane synthesized from Amino Trimethylene Phosphonic Acid (ATMP) and 3-Aminopropyltriethoxysilane (APTES) into cross-linked 1-Methylimidazole-functionalized poly(2,6-dimethyl-1,4-phenyleneoxide) (PPO) backbone. The structural characteristics of membranes were investigated using FT-IR, 1H NMR and XRD, indicating that ATMP and backbones of membranes were successfully immobilized into cross-linking Si-O-Si networks formed by hydrolysis-polycondensation of APTES. The resultant membranes named as HTM-X exhibited superior oxidative resistance, mechanical properties and dimensional stability, even the thermal stability was up to 210 °C. The proton conductivities of membranes were also measured under different temperature. The result showed that HTM-15 membrane, whose content of phosphonic acid functionalized siloxane was 15 wt%, possessed the highest proton conductivity of 8.48 × 10−2 S cm−1 at 160 °C and low relative humidity (5%) with the contribution of dual proton transfer channels of acid-base pairs and continuous hydrogen bond networks. Therefore, this novel membrane acts as a potential candidate for proton exchange membranes operating at elevated temperature.

Robust hydrophobic coating on glass surface by an atmospheric-pressure plasma jet for plasma-polymerisation of hexamethyldisiloxane conjugated with (3-aminopropyl) triethoxysilane

ABSTRACTPlasma polymerisation of hexamethyldisiloxane (HMDSO) and (3-aminopropyl)triethoxysilane (APTES) was attempted to form a robust hydrophobic coating film on glass surface. Although HMDSO is a common precursor for generating hydrophobic surface, the HMDSO-polymerised thin film is poor in strength. For the purpose of achieving the mechanical robustness of the coating, APTES was used together with HMDSO. Plasma polymerisation was performed using a dielectric barrier discharge plasma jet by varying the ratio of the two precursors to find a suitable condition that would produce robust hydrophobic thin film. Various instrumental techniques were used to characterise the coating layer. As a result of the examination of the hydrophobicity through the water contact angle measurements and the robustness by the scratch tests, the most reasonable coating was achieved at the HMDSO/APTES ratio of 3/1, the voltage of 7 kV and the treatment time of 60 s, and at this condition the WCA was 143°.

Cage-like hierarchically mesoporous hollow silica microspheres templated by mesomorphous polyelectrolyte-surfactant complexes for noble metal nanoparticles immobilization

In this paper, well-defined CHMSs were synthesized through co-hydrolysis of tetraethylsiloxane (TEOS) and 3-aminopropyltriethoxysilane (APTS) template by mesomorphous complexes of hexadecylpyridinium chloride (CPC) and poly(acrylic acid) (PAA). It was demonstrated that the adding amount of APTS in the reaction system played a key role in the formation of the hollow cage-like structure and a possible formation mechanism of CHMSs was proposed. The synthesized CHMSs presented as uniform microsphers with average diameter of 600 nm and possessed tri-model pore structure that were the ordered mesopores (˜3 nm) originated from CPC micelle, the secondary nanopores (˜55 nm) templated by phase separated PAA chain in the silica shell as well as the hollow cavity (several hundred nanometer). At the same time, the co-hydrolysis of APTS resulted in amino groups functionalized silica framework of the CHMSs. Ascribed to the unique structure and the inherent amino groups, the CHMSs were utilized as scaffold for preparation of heterogeneous noble metal nanoparticle catalysts. By choosing the palladium (Pd) as a typical example, 1-Pd@CHSMs catalysts containing 1.0 wt% Pd and uniform distributed small size Pd nanoparticles (˜2.9 nm) were obtained. The catalytic reduction of 4-nitrophenol demonstrated that the heterogeneous 1-Pd@CHSMs catalyst was efficient and reusable.

(3-aminopropyl) triethoxysilane grafted poly(dopamine)@Fe3O4 nanoparticles and their epoxy composites for functional application

The uniform dispersion of Fe3O4 nanoparticles and strong interfacial bonding with epoxy matrix are crucial for Fe3O4/epoxy composite with enhanced mechanical and thermal properties. Cube pure Fe3O4 nanoparticles (PF NPs) by poly (dopamine) (PDA) coated and (3-aminopropyl) triethoxysilane (APTES) grafted (PAF NPs) are successfully prepared via co-precipitation and seed polymerization method with an aim to enhance the dispersion and interfacial bonding with the epoxy matrix. The tensile strength of PAF/epoxy (1 wt%) increases from 57.8 MPa to 65.5 MPa (a rise scope of almost 13.3%) compared to pure epoxy. The thermal stabilities of PAF/epoxy composites with various PAF contents (1 wt%, 2 wt%, 3 wt%) are higher than that of pure epoxy. The saturation magnetization (Ms) of PAF/epoxy increases from 0.125 to 0.7 emu/g with PAF loading contents increasing from 0.5 to 3 wt%. The results suggest that dispersion and interfacial bonding of nanoparticles make a pivotal contribution to the enhanced performances of composites.

Anti‐Tumor Effect of Copper Sulfide Nanoparticles Carrying siRNA and Adriamycin

AbstractA combination of treatment strategies with two or more different mechanisms can together prevent cancer progression. In this paper, we present a combination of strategies with siRNA interference‐induced gene silencing, photothermal therapy and mesoporous drug delivery methods to cure cancer. First we synthesize oil‐soluble copper sulfide nanoparticles, which are modified with mesoporous silica and (3‐Aminopropyl)triethoxysilane (APTES), then use it as siRNA carrier to achieve siRNA transmission. At the same time, mesopores can also be used for drug delivery. Our results suggest that the copper sulfide nanomaterial loaded with siRNA and Adriamycin entered the cell successfully, and the composite can kill cancer cells effectively.

Phosphorimetric determination of 4-nitrophenol using mesoporous molecular imprinting polymers containing manganese(II)-doped ZnS quantum dots.

Mesoporous molecularly imprinted polymers (MIPs) containing mangnanese-doped ZnS quantum dots (Mn-ZnS QDs) were prepared for specific recognition and detection of 4-nitrophenol (4-NP). The Mn-ZnS QDs display orange room-temperature phosphorescence with excitation/emission peaks at 295/590nm and a decay time of 2.0 ms. In the presence of 4-NP, the orange phosphorescence is strongly reduced. Phosphorescence drops linearly in the 0.1-100μM 4-NP concentration range, and the detection limit is 60nM. The detection limit is far lower than the maximally allowed 4-NP concentrations in surface water and drinking water as specified by the U.S. Environmental Protection Agency. The intraday (n = 5) and interday (n = 6) spiked recovery rates were 96.0-104.5% and 97.9-107.9%, respectively, with relative standard deviations of 0.7-4.8% and 1.8-7.5% respectively. These MIPs integrated the characteristic features of phosphorimetry and molecular imprinting. Potential interference by competitive substances, background fluorescence or scattered light are widely reduced. Graphical abstract Schematic presentation of the synthesis of phosphorescent molecularly-imprinted polymers. A novel probe with manganese-doped ZnS quantum dots (Mn-ZnS QDs) and 3-aminopropyl-triethoxysilane (APTES) as functional monomers and tetraethoxysilane (TEOS) as crosslinking agent was prepared for selective phosphorescence detection of 4-nitrophenol (4-NP).

Superhydrophilic and oleophobic membrane functionalized with heterogeneously tailored two-dimensional layered double hydroxide nanosheets for antifouling

Fouling is a common challenge to all membrane-based separation technologies. The current study demonstrated an antifouling membrane with a superhydrophilic but oleophobic (in air) characteristic, which was achieved through covalently tethering heterogeneously tailored two-dimensional layered double hydroxide (LDH) nanosheets to a polyvinylidene fluoride membrane surface. The nanosheets were in situ grafted with alternately arranged sodium 1-dodecanesulfonate (SDS) and 3-aminopropyltriethoxysilane (APTS) chains during preparation. Poly(methacrylic acid) (PMAA) was previously grafted on the membrane via plasma induced graft copolymerization as anchor sites for nanosheet binding. With a simple dip-coating operation, the surface-tailored LDH nanosheets could be bound to the membrane via cross-linking between the amine groups of APTS and carboxyl groups of PMAA. Ultimately, the long hydrophobic SDS and short hydrophilic APTS chains on the nanosheets formed a heterogeneous and infiltration selective (due to steric exclusion) surface on the membrane. As a result, the hydrophilic moieties on the membrane surface were much more accessible to water than to liquids of larger molecular size, thereby bringing about the superhydrophilic but oleophobic characteristic. The functionalization gave rise to both significantly enhanced wettability and hydrophilicity of the membrane, mainly owing to the increase of the electron donor component of surface energy (γAB−). Additionally, the functionalized membrane obtained a greater permeability without compromising its selectivity. Furthermore, as verified in both filtration tests with synthetic and practical foulant solutions, the superhydrophilic and oleophobic characteristic endowed the functionalized membrane with conspicuously greater cleaning efficiency and excellent capability in resisting irreversible fouling, suggesting promising applications in various fields.

Waterborne polyurethane-silica nanocomposite adhesives based on castor oil-recycled polyols: Effects of (3-aminopropyl)triethoxysilane (APTES) content on properties

Waterborne castor oil-recycled polyol based polyurethane-silica nanocomposite adhesives (WPU) with polymer matrix and silica nanoparticles chemically bonded have been successfully prepared through a sol-gel process. A series of waterborne polyurethane adhesives with hard segment contents from 71.3 to 74.5 wt%, were synthesized using an isophorone diisocyanate, 2-bis(hydroxymethyl) propionic acid, recycled castor oil-based as soft segments and (3-aminopropyl)triethoxysilane (APTES) as chain extender. The depolymerized oligoester obtained from glycolysis of poly(ethylene terephthalate) (PET) waste using triethylene glycol (TEG), was transesterified with castor oil (CO) which resulted in the formation of hydroxyl-functional polyester polyol, with hydroxyl value of 414 mgKOH g−1. The molecular structures and mass of glycolyzed PET oligoesters, castor oil-based polyol and castor oil-based polyurethane-silica nanocomposite adhesives were estimated by Fourier transform infrared spectroscopy (FTIR) and gel permeation chromatography (GPC). The structure and properties of the resulting films were investigated by FTIR, wide angle X-ray diffraction measurement (XRD), thermogravimetry (TG) and differential scanning calorimetry (DSC). TG analysis indicated that APTES can improve the thermal stability of WPU. XRD showed that the crystallinity of WPU decreased with the increase alkoxysilane content. The extent of crosslinking was investigated to show a dependence on silica concentration, which increased the glass transition temperature and particle size of polyurethane nanocomposites with increasing alkoxysilane content due to the condensation of the alkoxysilane groups. The hardness, adhesion and gloss quality of the polyurethane films were also determined considering the effect of APTES content, so this paper confirmed the suitability of using these castor oil-based waterborne polyurethane-silica nanocomposites as new adhesive materials with high performance coatings materials. The experimental results reveal that the APTES and the hard segment content play a key role in controlling the structure and properties of the PU cast films based on castor oil-recycled polyols.

Development of amino-functionalized silica nanoparticles for efficient and rapid removal of COD from pre-treated palm oil effluent

In this study, low cost synthesis of three-dimensional mesoporous amino-functionalized silica nanoparticles (AFS-NPs) were synthesized by sol–gel method with the addition of two different silica modifiers, 3-aminopropyltrimethoxysilane (APTMS) and 3-aminopropyltriethoxysilane (APTES) to two different silica sources, tetramethoxyorthosilicate (TMOS) and tetraethoxyorthosilicate (TEOS) separately. The presence of amino group on synthesized nanoparticles from the four different combinations was confirmed by Fourier transform infrared (FTIR) spectroscopy. The synthesized AFS-NPs were of narrow particle size within the range of 500–600nm and having high specific surface area (148m2g−1). The AFS-NPs were then utilized to investigate the adsorptive removal of COD from palm oil mil effluent (POME). The maximum removal efficiency (>90%) of AFS-NPs was found at pH 7, adsorbent dose 0.25g and temperature 30°C. At equilibrium the maximum adsorption capacity was found to be 271.11mgg−1. The Langmuir adsorption isotherm gave the best fit to the experimental data signifying the presence of adsorption monolayer on the surface of the adsorbent. The results have positively qualified grafted silica nanoparticles as one of the adsorptive media for removal of COD from POME.

Potential roles of fluorine-containing sol-gel coatings against adhesion to control microbial biofilm

Treatment of materials by sol-gel technique can be an excellent tool to convey new properties to surfaces, therefore the hybrid organic-inorganic materials show the properties of both phases, contributing for example to the obtainment of an anti-fouling coating. In this research, the explored procedure includes the co-condensation of silane coupling agents with epoxide and amine tail-groups, (3-Glycidyloxypropyl)-trimethoxysilane (GPTMS) and (3-Aminopropyl)-triethoxysilane (APTES), respectively, in combination with two perfluorosilane precursors, namely glycidyl-2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9-hexadecafluorononylether and trimethoxy-(3,3,3-trifluoropropyl)-silane, either individually or together. This synthetic approach allows collecting stable hydrophobic, non-toxic, anti-fouling coatings that were investigated to study their morphology and chemical structure by different physical-chemical techniques. The anti-fouling properties were evaluated through test on treated glass slides in different microbial suspension in seawater-based medium per 24 h at room temperature. During tests, each suspension was maintained in continuous agitation to simulate the natural movement of seawater, and the attachment of cells on bare degreased glass slides is compared with that occurring on the treated slides. Results show that the fluorinated coatings have good antimicrobial activities and low adhesive properties, no biocidal effects towards the studied microorganisms were observed.

Multifunctional self-assembled monolayers via microcontact printing and degas-driven flow guided patterning

Soft lithography-based patterning techniques have been developed to investigate biological and chemical phenomena. Until now, micropatterning with various materials required multiple procedural steps such as repeating layer-by-layer patterning, aligning of stamps, and incubating printed inks. Herein, we describe a facile micropatterning method for producing chemically well-defined surface architectures by combining microcontact (µCP) and microfluidic vacuum-assisted degas-driven flow guided patterning (DFGP) with a poly(dimethylsiloxane) (PDMS) stamp. To demonstrate our concept, we fabricated a bi-composite micropatterned surface with different functional molecular inks such as fluorescein isothiocyanate labelled bovine serum albumin (FITC-BSA) and polyethylene glycol (PEG)-silane for a biomolecule array, and 3-aminopropyltriethoxysilane (APTES) and PEG-silane pattern for a self-assembled colloid gold nanoparticle monolayer. With a certain composition of molecular inks for the patterning, bi-composite surface patterns could be produced by this µCP-DFGP approach without any supplementary process. This patterning approach can be used in microfabrication and highly applicable to biomolecules and nanoparticles that spread as a monolayer.

Improvement of mechanical strength of hydrophobic coating on glass surfaces by an atmospheric pressure plasma jet

Non-thermal plasma is getting more popular in industrial applications, mainly treatment of material surfaces. Hydrophobic coatings often suffer mechanical instability and do not function well after abrasion/scratching. In this study, non-thermal plasma jet generated at atmospheric pressure in ambient condition was applied to the hydrophobic treatment of glass surface using two precursors. Tetramethylsilane (TMS) was used to promote hydrophobicity and (3-Aminopropyl)triethoxysilane (APTES) was used to get durable mechanical strength of the coating although it is hydrophilic in character. An alternating current (AC) high voltage (operating frequency: 11.5 kHz) was used to generate plasma jet for producing a coating layer onto the soda-lime glass sample. Water contact angle of 139° and a stable mechanical strength were achieved at an optimal TMS/APTES ratio of 4.8. The coating thickness, strength and water contact angle were varied by changing treatment time, applied voltage, and carrier gas (argon) flow rate. The coating layer were characterized by atomic-force microscopy (AFM), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), water contact angle (WCA), scratch test and UV/visible spectroscopy.

Effect of chitosan on the fire retardancy and thermal degradation properties of coated cotton fabrics with sodium phytate and APTES by LBL assembly

Chitosan was added to cotton fabrics coated with sodium phytate and 3-Aminopropyl triethoxysilane (APTES) to further enhance the fire retardant property by the layer-by-layer (LBL) assembly. The surface morphologies before and after flaming and structure of coated cotton fabrics were evaluated by scanning electron microscopy and Fourier transform infrared analysis. The thermal degradation properties, fire retardancy, and combustion properties of this system were investigated by Fourier transform infrared analysis, thermogravimetric analysis coupled with Fourier transform infrared analysis (TG-FTIR) in the N2 atmosphere, the thermogravimetric analysis in air atmosphere, limiting oxygen index test (LOI), vertical burning test and cone calorimeter test, respectively. Sodium phytate, chitosan and hydrolyzed APTES were successfully deposited and well distributed on the surface of cotton fibers. The LOI value of the coated cotton fabric with 15BL was 29.0%, and it extinguished at once in the vertical burning test, while the coated cotton fabrics with 5BL and 10BL were burned out. The deposition of sodium phytate, chitosan and hydrolyzed APTES led to the decrease of heat release rate, total heat release, total smoke release and smoke production rate. The promoted fire retardancy was assigned to thermally stable residuals formed on the surface of cotton fibers, which prohibited heat/mass transfer from combustion zone to polymer degradation zone. TG-FTIR results indicated that flame retardant cotton fabrics produced more nonflammable gases (CO2 and H2O) and less combustible gases than them of the control sample did, increasing flame retardant properties of flame retardant cotton fabrics.

Synthesis on aggregation of colloidal solutions of ICG-active silica nanoparticles and their application in in‐vivo fluorescence imaging

This study reports two findings. The first is a method for preparing a colloidal solution of silica (SiO2) nanoparticles activated with fluorescent dye or fluorescent dye-active SiO2 nanoparticles. Preparation of a colloid solution of spherical SiO2 nanoparticles with an average size of 109.4 ± 8.6 nm was performed using the sol-gel method at 35 °C using 0.2 M tetraethylorthosilicate, 25 M H2O, and 0.01 M NaOH in ethanol. Two kinds of cationic chemicals (poly-diallyldimethylammonium chloride (PDADMAC) and (3-aminopropyl) triethoxysilane (APES) were examined for surface-modification or surface-cationization of the SiO2 nanoparticles (SiO2/PDADMAC and SiO2/APES). To activate the SiO2 nanoparticles with fluorescent dye, indocyanine green (ICG) molecules were fixed on the surface-modified SiO2 nanoparticles by mixing ICG dissolved in albumin aqueous solution and the surface-modified SiO2 nanoparticle colloid solution (SiO2/PDADMAC/ICG and SiO2/APES/ICG) through electrostatic aggregation. The second finding is the verification of the fluorescence ability of the ICG-active SiO2 nanoparticle colloid solutions. Both the ICG-active SiO2 nanoparticle colloid solutions exerted fluorescence even at high ICG concentrations. Mouse tissues could be imaged by injecting the ICG-immobilized SiO2 nanoparticle colloid solution into the tail vein of the mouse and measuring the emitted fluorescence intensity. Pulmonary embolism was avoided in the SiO2/APES/ICG particle colloid solution-injected group, in which the particles reached the tissues more efficiently than in the SiO2/PDADMAC/ICG nanoparticles-injected group.

A light-weight and high-efficacy antibacterial nanocellulose-based sponge via covalent immobilization of gentamicin

Covalent grafting of gentamicin to nanocellulose-based sponge was realized for the first time. The named sponge was prepared by initially multi-crosslinking among cellulose nanofibers (CNF), cellulose acetoacetate (CAA) and 3-aminopropyl(triethoxy)silane (APTES) followed by surface modification with gentamicin via the formation of enamine bond. The structure and mechanical performances of the obtained gentamicin-functionalized CNF sponge were characterized with FT-IR, XPS, EDX, SEM, Nitrogen adsorption-desorption measurement, and compressive test. Its antibacterial activity against E. coli and S. aureus was evaluated using disc diffusion and colony forming units (CFU) count methods. The results showed that gentamicin was successfully grafted on the surface of CNF sponges without significant change in morphology and slight improvement in mechanical performance. The superior lightness of the sponge (0.0174 g cm−3) was demonstrated by showing the sponge could be supported by a flower branch without crushing it. Gentamicin-functionalized CNF sponges showed excellent antibacterial performance against E. coli and S. aureus, with bactericidal rates of over 99.9%.

Tannin-APTES modified Fe3O4 nanoparticles as a carrier of Methotrexate drug: kinetic, isotherm and thermodynamic studies

In the present study, tannin and 3-Aminopropyltriethoxysilane (APTES) functionalized magnetic nanoparticles (Tan-A-MNP (was synthesized and the adsorption of methotrexate (MTX) drug was studied. The surface morphology and characteristics of Tan-A-MNP was determined by FTIR, SEM, TEM and XRD analysis. The optimum values of the effective parameters such as pH, carrier dosage, drug concentration, contact time and temperature were determined. The maximum adsorption of MTX on Tan-A-Fe3O4 was obtained about 91% based on the optimum conditions. The FTIR and TEM analysis of Tan-A-Fe3O4 indicated that NH and OH groups play an important role in MTX adsorption. According to the study of equilibrium data and comparison of four types of isotherm models, Langmuir isotherm with adsorption capacity of 55.55 mg/L was the predominant model. So, monolayer adsorption of MTX was occurred. Pseudo second order kinetic model was more compatible with the equilibrium data than that of first order model. Intra-particle kinetic model also revealed that boundary layer effects can affect on the kinetic of drug adsorption. Thermodynamic analysis exhibited that MTX adsorption was endothermic and spontaneous.

Natural rubber as a template for making hollow silica spheres and their use as antibacterial agents

A method is reported for synthesizing hollow silica spheres (HSS) using skimmed natural rubber (NR) latex as template. Tetraethyl orthosilicate (TEOS) and (3-aminopropyl) triethoxysilane (APTES) were used as the silica source and the co-structure directing agent, respectively. Effects of the TEOS/APTES mole ratio, the synthesis pH, and the total silica content relative to rubber, on HSS formation were observed through transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Skimmed NR latex proved to be a suitable natural template because the rubber particles in it were generally spherical and the ammonia (NH 3 ) conventionally added to the latex as a preservative served as the catalyst for the synthesis of silica. The suitable pH range for forming the hollow structures was 7–10, so long as the TEOS/APTES mole ratio was satisfactory and the total silica available was sufficient. The optimal conditions for forming HSS with robust shells were a TEOS/APTES mole ratio of 1:1, pH 10, and a total silica content of 200 phr. The silver-loaded HSS had excellent antibacterial activity against Escherichia coli . • Skimmed natural rubber latex was used to make hollow silica spheres (HSS). • A sol-gel process with tetraethyl orthosilicate as the silica source was used. • The co-structure directing agent was (3-aminopropyl) triethoxysilane. • A method was developed for loading the HSS with silver ions (Ag + ). • Ag-loaded HSS had superior antibacterial activity compared to a solution of AgNO 3 .

APTES AND TEOS MODIFIED BINARY RECYCLABLE HYBRID FE3O4@GO NANOCOMPOSITE FOR PHOTOCATALYTIC DYE REMOVAL

Methylene blue (MB) is one of the industrial used organic dye and recalcitrant pollutant which creates a serious water pollution. Among the available techniques, photo degradation using light irradiation is one of the desirable choice to treat waste water. In this regard, we synthesized a binary nanocomposite of magnetite decorated with graphene oxide sheet (Fe3O4@GO) with modification of tetraethyl orthosilicate (TEOS) and 3-Aminopropyl triethoxysilane (APTES) by mechanical stirring method. The prepared nanocomposite was tested as a potential heterogeneous catalyst for degradation of methylene blue (MB) under UV irradiation. The synthesized nanoparticles were characterized by using X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), Fourier transform infrared (FTIR), Thermogravimetric Analysis (TGA), and Energy-dispersive X-ray spectroscopy (EDX) techniques. The characterizations confirm the successful synthesis of the nanocomposite. The photocatalytic activity of the catalysts was gradually enhanced with time intervals. The maximum MB removal efficiency of 70.06 % was achieved over Fe3O4@GO composite catalyst, remarkably higher than using pure Fe3O4 (57.56 %). The newly developed materials was successfully recovered using an external magnet.

Immobilization of the enzyme invertase in SBA-15 with surfaces functionalized by different organic compounds

The search for appropriate supports for enzyme immobilization has attracted increasing interest in the field of biocatalysis. Immobilized enzymes are catalysts of enormous industrial interest because they combine the advantages of heterogeneous catalysis with the high selectivity and mild operational conditions of enzymes. This study evaluated the use of different organic molecules as functionalizing agents anchored on the silanol groups present on the surface of mesoporous materials such as SBA-15. This modification aims to increase the interaction of the enzyme invertase to the support, allowing for a greater amount of this biocatalyst to be immobilized. The hexagonal mesoporous material SBA-15, which has pores in the range of 40–60 A, was synthesized and modified by the following organic compounds: trimethoxyphenylsilane, vinyltrimethoxysilane and 3-aminopropyltriethoxysilane (APTES). APTES showed the best results in increasing the anchoring of enzymes on the material’s surface, providing a specific amount of enzyme loaded onto the surface of approximately 80% and, thus, showing successful functionalization.

Grafting of quantum dots on covalent organic frameworks via a reverse microemulsion for highly selective and sensitive protein optosensing

A novel reverse microemulsion strategy coupled with surface imprinting technology is developed for the synthesis of CdSe/ZnS quantum dots (QDs)-grafted covalent organic frameworks (COFs) that were used for optosensing protein. COFs are unique in that they are made from lighter elements have tunable skeletons, compared with inorganic porous materials. The functional COFs have become the attractive promising candidates for diversified applications. In this study, a novel thermally and chemically stable three-dimensional crystalline array of QDs grafted on COFs was synthesized, which was performed by Schiff base reactions of 1,3,5-triformylphloroglucinol-P-phenylenediamine (TpPa) and 3-aminopropyltriethoxysilane (APTEs)-modified CdSe/ZnS quantum dots. TpPa was treated as supports to enhance the sensitivity, and APTES modified QDs were employed as tentacle to selectively and sensitively sense the protein-bonding interactions, and further transduce it to the detectable fluorescence signals. The QD-grafted COFs exhibited high thermal stability, repeatability, selective and sensitive optosensing of protein, and the low detection limits was 5.4 × 10−4 mg/mL. The proposed strategy provides a promising method for the fabrication of QDs-grafted COFs and the great potential of QDs-grafted COFs as a sensing platform for protein detection.