Sol-gel System Research Articles

Magnetic relaxation switching biosensor for one-step detection of Vibrio parahaemolyticus based on click chemistry-mediated sol-gel system

In this study, a magnetic relaxation switching (MRS) biosensor was developed for one-step detection of pathogenic bacteria Vibrio parahaemolyticus (VP). The biosensor is based on a click chemistry-mediated sol-gel system and utilizes low-field nuclear magnetic resonance (LF NMR) detection. VP aptamer (Apt)-coated hollow mesoporous silica microspheres (HMSMs) with saturated sodium ascorbate (SAA) solution sealed inside, HMSMs@SAA&Apt, are designed as the signal unit. When the target VP is present, the Apt binds to VP and releases SAA from the signal unit. The released SAA reduces Cu2+ in the test solution to Cu+, which catalyzes the click chemistry reaction between azide-modified polyethylene glycol (PEG-Azide) and acetylene-modified polyacrylic acid (PAA-Alkyne). The sol-gel transition is triggered, a large amount of "free" water is converted into "bound" water, resulting in the decrease of transverse relaxation time (T2). Under the optimal experimental conditions, the variation of T2 (ΔT2) was linearly related to the logarithm of VP concentration in the range of 10 ∼ 1.0 × 108 CFU/mL, with a limit of detection of 5 CFU/mL. The assay demonstrated good selectivity, stability, and reproducibility. It is completed in one step, holding promising applications in the rapid field detection of pathogenic bacteria.

Two-layer hybrid sol-gel system's thermal parameters investigated with the optical nondestructive photoacoustic method in the frequency domain

This work presents results of studies of thermal parameters such as thermal diffusivity, thermal conductivity, thermal effusivity and volumetric heat capacity of thin hybrid sol-gel corrosion protective layers deposited on the aluminum substrate. In the studies two groups of samples were investigated. The first group was: TMZ.1, TMZ.2 and TMZ.3 (TMZ- Si/Zr-based hybrid sol-gel coatings), with different amount of zirconium, and the second group was: TMZ.1/Ce, TMZ.2/Ce and TMZ.3/Ce (TMZ/Ce - Ce-doped Si/Zr-based hybrid sol-gel coatings) with the same amount of zirconium and an addition of cerium. This work presents the influence of the content of zirconium and cerium on their thermal parameters. The possibility of using the nondestructive photoacoustic method (PA), with the microphone detection, to characterize this type of layers was analyzed theoretically and experimentally too.

Precise identification and ultrafast transport of specific molecules with nanofluid-functionalized imprinted membrane

Membrane-based imprinted sites for achieving specific molecule transport and precise recognition have great potential to revolutionize nanofiltration technology. Nonetheless, how to efficiently prepare imprinted membrane structures with accurate identification - ultrafast molecular transport - high stability in mobile phase remains a key issue and serious challenge. Herein, we have developed a dual-activation strategy to constructing nanofluid-functionalized membranes with double imprinted nanoscale channels (NMDINCs), realizing ultrafast transport performance as well as structure&size-exclusion selectivity in allusion to particular compounds. The resultant NMDINCs, founded on principal nanofluid-functionalized construction companied by the boronate affinity sol-gel imprinting systems, illustrated that delicate regulation towards polymerization framework as well as functionalization belonging to distinctive membrane structures was crucial for realizing ultrafast molecules transport combined with prominent molecules selectivity. The synergistic recognition of covalent bonds and non-covalent bonds driven by two functional monomers effectively realized the selective recognition to template molecules, leading to the high selective separation factors of Shikimic acid (SA)/ Para hydroxybenzoic acid（PHA）, SA/ P nitrophenol（PN）and catechol（CL）for 8.9, 8.14 and 7.23, respectively. The dynamic consecutive transport outcomes exhibited that numerous SA-dependent recognition sites could still keep reactivity under pump-driven permeation pressure for appreciable time, forcefully proving the successful construction as to high-efficiency membrane-based selective separation system. It is anticipated that this strategy as to the in situ introduction of nanofluid-functionalized construction into porous membrane would hold great promise in preparing high-intensities membrane-founded discriminating separation systems, which was equipped with prominent consecutive permeability as well as excellent selectivity.

Sol-gel coatings with the fluorescence dye Rhodamine B for optical modification of cotton

The sol-gel method is a versatile tool for the modification and functionalization of textiles. This method can be also used to support the application of dyes on textile materials. This paper is related to the application of the fluorescence dye Rhodamine B together with an industrial sol-gel component. Beside fluorescence spectroscopy, also scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) are used for the investigation of the produced textile samples. The realized fluorescence effects are strongly related to the applied dye concentration and can be drastically enhanced by presence of the applied sol-gel system. By use of sol-gel method also the dry and the wet rubbing fastness can be improved. These results could be the starting point for future development of new fluorescent textile materials.

Cross-linking processes in antimicrobial UV-sol-gel systems initiated by atmospheric pressure plasma

Sol-gel systems are becoming increasingly popular in the coating industry. However, current coatings are only a few 100 nanometers thick. Due to high stress, e.g., in the aerospace industry, such coatings wear out too quickly and lose their protective effect. Using an atmospheric pressure plasma source, we can cure thicker sol-gel layers both completely and faster and functionalize the coating in a single step. In this contribution, we treat sol-gel layers to make them scratch-resistant, anti-adhesive, and antimicrobial by adding Cu particles. Fourier transform infrared spectroscopy can determine the degree of curing. Additionally, transient thermal finite element calculations were performed to optimize plasma curing parameters and prevent local thermal damage to the sol-gel system and the substrate material. This combination of simulation and experiments allowed a quick determination and solution of the treatment shortcomings.

Quality optimization of Bi2212 films prepared by aqueous solvent sol-gel method with nonionic surfactants

In this paper, Bi2212 films were prepared on LaAlO3(100) and SrTiO3(100) substrates by the sol-gel method using Bi(NO3)3·5H2O, Sr(NO3)2, Ca(NO3)2·4H2O and Cu(NO3)2·3H2O as raw materials. TritonX-100 (TX-100), fatty alcohol poly oxyethylene ether (AEO-9), poly (vinylpyrrolidone) (PVP) and poly (vinyl alcohol) (PVA) were used as surfactants, respectively, to improve the wettability between the sol and the substrate. When glycine and glycolic acid were used as complexing agents, these surfactants were stably miscible with the sols. The effects of different surfactant sol-gel systems on the wettability of substrates as well as the crystallinity, morphology, surface roughness and electrical transport properties of Bi2212 superconducting films were investigated. The results showed that flat and continuous c-axis epitaxial Bi2212 films were obtained using all these sol-gel systems. In particular, TX-100 and AEO-9 as surfactants showed stronger wettability of the sol-gel for both substrates. In addition, the films prepared using polymer surfactants PVP and PVA sol-gel systems showed less surface roughness. The same patterns were found in all the film samples prepared using precursor sols of different complexing agents, and all the films exhibited good electrical transport properties. This work lays a certain research foundation for the preparation of thin films by aqueous solvent sol-gel method. The method also shows great potential in terms of the stability of different sol-gel systems and the improvement of the wettability of different substrates.

Enhanced flame retardancy level of a cotton fabric treated by an ammonium pentaborate doped silica-KH570 sol

Tetraethoxysilane (TEOS), γ- (methacryloyloxy) propyltrimethoxysilane (KH570) and ammonium pentaborate (AP, NH4B5O8) were used as a precursor, silane coupling agent and flame retardant additive to prepare a series of single (SiO2), composite (SiO2-KH570) and doped (SiO2-KH570-AP) sols via sol-gel processes. The sols were post finished to cotton fabrics through dipping-curing methods. Results show that as-prepared sol-gel systems are successfully deposited on cotton fabrics. SiO2-KH570-AP@COT shows the highest initial pyrolysis temperatures (296.4°C), char residue rate (31.5%), LOI (24.0%) and ΔLOI/Δm (4.75%/g), the most beneficial after-flame time (14.1 s) and after-glow time (0.0 s), the most complete char residue (30.0 cm), the second highest maximum pyrolysis temperature (356.6°C) and an effective synergistic effectiveness parameter (>1.0). Its flame retardancy is mainly promoted by both individually positive and jointly synergistic actions of silica sol (strong physical barrier and structural support effects in enhancing thermal stability and providing char frame), KH570 (strong coupling effect in combining components and reinforcing interface properties between components and cotton fibers) and AP (release of water molecules for cooling burning zone, diluting and isolating oxygen and gaseous products and promoting char formation). The flame-retardant treatment deteriorated the tensile strength of cotton fabrics.

Material extrusion for ceramic additive manufacturing with polymer-free ceramic precursor binder

Additive manufacturing of dense ceramic products has been challenging because of the high polymeric content of the ceramic feedstock materials. Several studies have been conducted to increase the ceramic content in the feedstock, but the binder and additives in it have remained in the polymeric content. A novel strategy for highly dense additive manufacturing using a sol-gel-based ceramic slurry without polymeric additives is presented. Alumina, which is the most widely used fine ceramic, was chosen as a representative ceramic material. The proposed sol-gel solution enabled a high solid loading of approximately 50 vol% without any polymeric dispersant while satisfying the requirements for material extrusion process, such as extrudable viscosity (<100 Pa.s) and self-sustainable yield stress. This novel sol-gel binder system evolves into aluminum oxide nanoparticles during the sintering process, eventually fusing to the alumina particles. The as-printed green body possessed high alumina content and 66% of theoretical density, which was higher than that obtained via the conventional molding methods. A reduced linear shrinkage of less than 16% and a high density of 99.5% of the theoretical value were also achieved. This research would present a practical strategy for ceramic additive manufacturing as an emerging fabrication process.

Bioactive, Degradable and Tough Hybrids Through Calcium and Phosphate Incorporation

We report the first inorganic/organic hybrids that show outstanding mechanical properties (withstanding cyclic loading) and bone bioactivity. This new hybrid material may fulfil the unmet clinical need for bioactive synthetic bone grafts that can withstand cyclic loading. A SiO2/PTHF/PCL-diCOOH sol-gel hybrid system, that combined inorganic and organic co-networks at the molecular level, previously demonstrated unprecedented synergy of properties, with excellent flexibility and promoted formation of articular cartilage matrix in vitro. Here, for the first time, calcium and phosphate ions were incorporated into the inorganic component of the hybrid network, to impart osteogenic properties. Calcium methoxyethoxide and triethyl phosphate were the calcium and phosphate precursors because they allow for incorporation into the silicate network at low temperature. The hybrid network was characterised with ATR-FTIR, XRD and solid-state Nuclear Magnetic Resonance, which proved calcium and phosphate incorporation and suggested the Ca2+ ions also interacted with PCL-diCOOH through ionic bonds. This resulted in an increased strength (17–64 MPa) and modulus of toughness (2.5–14 MPa) compared to the original SiO2/PTHF/PCL-diCOOH hybrid material (which showed strength of ∼3 MPa and modulus of toughness of ∼0.35 MPa), while also maintaining the ability to withstand cyclic loading. The presence of calcium and phosphates in the silicate network resulted in a more congruent dissolution of the inorganic and organic co-networks in TRIS buffer. This was shown by the presence of silicon, calcium and phosphate ions along with PCL in the TRIS buffer after 1 week, whereas Ca-free hybrids mainly released PCL with negligible Si dissolution. The presence of calcium and phosphates also enabled deposition of hydroxycarbonate apatite following immersion in simulated body fluid, which was not seen on Ca-free hybrid. All hybrids passed cell cytotoxicity tests and supported pre-osteoblast cell attachment. The phosphate-free hybrid showed the best mechanical behaviour and supported better cell attachment, spreading and potentially differentiation of cells. Therefore, the SiO2-CaO/PTHF/PCL-diCOOH hybrid represents a promising biomaterial for use in bone regeneration.

Analytical time series alignment liquefaction number of corn starch mixture

The statistical description of the development of dynamic processes in time is carried out using time series. To eliminate random fluctuations and build an analytical function of the trend of the time series, an analytical alignment procedure is used. The choice of the type of the trend function is carried out by the method of finite differences, the calculation of the trend parameters ‒ by the method of least squares. The purpose of this work was the analytical alignment of the time series of the liquefaction number of the corn starch mixture obtained in the experiment on the PChP-99 device. The mechanism of starch gelatinization with a given liquefaction rate under such conditions requires additional theoretical and experimental study. Calculations have shown that the process of liquefaction of starch gel corresponds to the exponential trend equation: y = a • ebt, which is a particular case of an exponential trend. It has been experimentally established that an increase in the proportion of amylopectin starch in a corn starch mixture leads to an increase in the maximum viscosity of the resulting gel when the swelling water-starch suspension is heated. In the process of further gelatinization of corn starch mixture with an increase in the proportion of amylopectin starch, the strength of the gel decreases due to the preservation of the mobility of water molecules during the transition in the sol-gel system, which contributes to an increase in liquefaction number. Experimental data do not contain anomalous values; the error in approximating the regression equation for the trend of the time series is less than 5 %. The statistical significance of the coefficients of the linearized trend equation is proved in favor of the hypothesis of the existence of a time series. The obtained estimates of the regression equation make it possible to use it for predictive purposes, providing an accuracy of up to 95.42 % of the total variability of the liquefaction number in the absence of autocorrelation of first-order residues. Checking the normality of the distribution of the residual component according to the RS test showed the adequacy of the trend model, the hypothesis of the absence of heteroscedasticity according to the Spearman and Goldfeld-Quandt tests is accepted.

Joining of SiC Ceramic by Si-C Reaction Bonding Using Organic Resin as Carbon Precursor.

In this study, the joining of silicon carbide (SiC) ceramics was achieved via a Si–C reaction bonding method using the phenolic resin (PF)–MgCl2 system as the carbon precursor. Specifically, by adding MgCl2 to the phenolic resin mixture, the average pore size of the product of carbonization of the PF resin mixture increased from 14 ± 5 nm to 524 ± 21 nm, which was beneficial for the infiltration of molten silicon at high temperature. The microstructure of the joined specimens and the effect of the inert filler on the joint strength were investigated. It was demonstrated that SiC–SiC joints with strong interfacial bonding and high flexural strength could be obtained by the Si–C reaction bonding method using a phenol formaldehyde resin/alcohol sol-gel system as the carbon precursor. The flexural strength of the joined specimens reached the highest value, i.e., 308 ± 27 MPa when the solid loading of the inert filler was 26%. Overall, stable joining of silicon carbide ceramics was achieved by the proposed method, which has significance for realizing the preparation of complex-shaped or large silicon carbide ceramic parts.

Structural Rearrangements of Carbonic Anhydrase Entrapped in Sol-Gel Magnetite Determined by ATR–FTIR Spectroscopy

Enzymatically active nanocomposites are a perspective class of bioactive materials that finds their application in numerous fields of science and technology ranging from biosensors and therapeutic agents to industrial catalysts. Key properties of such systems are their stability and activity under various conditions, the problems that are addressed in any research devoted to this class of materials. Understanding the principles that govern these properties is critical to the development of the field, especially when it comes to a new class of bioactive systems. Recently, a new class of enzymatically doped magnetite-based sol-gel systems emerged and paved the way for a variety of potent bioactive magnetic materials with improved thermal stability. Such systems already showed themself as perspective industrial and therapeutic agents, but are still under intense investigation and many aspects are still unclear. Here we made a first attempt to describe the interaction of biomolecules with magnetite-based sol-gel materials and to investigate facets of protein structure rearrangements occurring within the pores of magnetite sol-gel matrix using ATR Fourier-transform infrared spectroscopy.

Dependence of the structure of Bi-2212 superconducting thin film prepared by sol-gel method on different complexing agents

The complexed sol-gel method has unique advantages in the preparation of multi-component functional thin films. In this paper, Bi2212 superconducting thin films were prepared by sol-gel method on SrTiO3(100) single crystal substrates. Glycine and glycolic acid were used as complexing agents. The thermal decomposition processes of the two sols were analyzed by contrasting thermal-thermogravimetric curves. The heat treatment processes of the different complexing agent systems were optimized to obtain films with flatter surface morphology. The phase composition of the intermediate products during the precursor heat treatment was changed by adjusting the conditions of the complexing agent and the acidity of the sol, which expanded the pure phase temperature interval of the final product. The pure phase temperature interval, morphology, surface roughness, and electrical transport properties of Bi2212 superconducting films prepared with different complexing agent sol-gel systems were investigated. When glycolic acid was used as the complexing agent, the Bi-2212 superconducting films showed the widest phase formation temperature zones of 25 K. They also had a smaller surface roughness of 10–15 nm. Other than that, all samples had good epitaxial properties, and electrical transport properties. This work provides a new idea for expanding the phase-forming temperature region of multicomponent functional ceramics. It also shows the promising potential of sol-gel method for preparing multicomponent functional films with high quality surfaces.

Wood-based multi-layered porous imprinted membranes with dual-metal composite nanostructures: Synergistic promotion of rebinding capacity, selectivity and permeability

Herein the Ag&TiO2-based propranolol-imprinted layers had been prepared onto basswood membrane surface based on a polydopamine (PDA)-induced self-polymerization/composite strategy. The as-prepared PDA-induced Ag&TiO2-based molecularly imprinted nanocomposite membranes (PAT-MIMs) showed superb specific recognition capability and permselectivity toward the template molecule of propranolol. Thereinto, the natural curved channel of basswood could efficiently promote the diffusion process of propranolol and improve the contact efficiency with surface recognition sites. Describing the entire synthetic strategy, the as-prepared PDA-induced Ag&TiO2-modified basswood-based membrane structure had been regarded as a threefold sol-gel imprinted-initiated system, thus constructing the propranolol-imprinted sites with key properties of high selectivity and rapid specific-recognizability. Therefore, enhanced adsorption performance of 118.6 mg/g, fast adsorption rate (within 30 min) and high permselectivity rates (more than 3.0) had been successfully harvested, which clearly illustrated the successful preparation of high-intensitive recognizability and permeability toward propranolol from complex separation system.

Formulation and Evaluation of Nano Lipid Carrier-Based Ocular Gel System: Optimization to Antibacterial Activity

The present research work was designed to prepare Azithromycin (AM)-loaded nano lipid carriers (NLs) for ocular delivery. NLs were prepared by the emulsification–homogenization method and further optimized by the Box Behnken design. AM-NLs were optimized using the independent constraints of homogenization speed (A), surfactant concentration (B), and lipid concentration (C) to obtain optimal NLs (AM-NLop). The selected AM-NLop was further converted into a sol-gel system using a mucoadhesive polymer blend of sodium alginate and hydroxyl propyl methyl cellulose (AM-NLopIG). The sol-gel system was further characterized for drug release, permeation, hydration, irritation, histopathology, and antibacterial activity. The prepared NLs showed nano-metric size particles (154.7 ± 7.3 to 352.2 ± 15.8 nm) with high encapsulation efficiency (48.8 ± 1.1 to 80.9 ± 2.9%). AM-NLopIG showed a more prolonged drug release (98.6 ± 4.6% in 24 h) than the eye drop (99.4 ± 5.3% in 3 h). The ex vivo permeation result depicted AM-NLopIG, AM-IG, and eye drop. AM-NLopIG exhibited significant higher AM permeation (60.7 ± 4.1%) than AM-IG (33.46 ± 3.04%) and eye drop (23.3 ± 3.7%). The corneal hydration was found to be 76.45%, which is within the standard limit. The histopathology and HET-CAM results revealed that the prepared formulation is safe for ocular use. The antibacterial study revealed enhanced activity from the AM-NLopIG.

Eu3+ as a Powerful Structural and Spectroscopic Tool for Glass Photonics.

The unique properties of the Eu3+ ion make it a powerful spectroscopic tool to investigate structure or follow processes and mechanisms in several high-tech application areas such as biology and health, structural engineering, environment monitoring systems and quantum technology, mainly concerning photonics. The traditional method is to exploit the unique photoluminescent properties of Eu3+ ions to understand complex dynamical processes and obtain information useful to develop materials with specific characteristics. The objective of this review is to focus on the use of Eu3+ optical spectroscopy in some condensed matter issues. After a short presentation of the more significant properties of the Eu3+ ion, some examples regarding its use as a probe of the local structure in sol–gel systems are presented. Another section is devoted to dynamical processes such as the important technological role of nanocrystals as rare-earth sensitizers. The appealing effect of the site-selection memory, observed when exciting different sites into the 5D1 state, which the 5D0 → 7F0 emission band reflects following the sites’ distribution, is also mentioned. Finally, a section is devoted to the use of Eu3+ in the development of a rare-earth-based platform for quantum technologies.

Proton-conducting Organic-inorganic Sulfo-containing Membranes for Fuel Cell

Cross-linked organiс-inorganic sulfo-containing membranes of various compositions based on acrylic monomers (acrylonitrile, acrylic acid, 3-sulfopropylacrylate potassium salt, ethylene glycol diacrylate) and sol-gel systems of tetraethoxysilane have been developed. Synthesis of the polymer matrix was carried out by UV-initiated polymerization of the monomer mixture and the inorganic component was formed in situ while conducting the sol-gel process of the precursor. FTIR, SEM, EDS, DMA, impedance spectroscopy were used to characterize the synthesized materials. The influence of inorganic component content on the properties of the membranes was investigated. DMA results show that an increase in silica content leads to a decrease in packing density and an increase in structural heterogeneity in sulfo-containing polyacrylate/silica membranes. The highest values of proton conductivity 1.12 ꞏ 10−2 Sm/cm at 60 °C were found in membranes containing 3 wt.%. of the added sol-gel system. Further increase of silica content does not increase the proton conductivity of the membranes. The proton transfer activation energies in the membranes were calculated from the temperature dependence of proton conductivity. The obtained cross-linked sulfo-containing organic-inorganic materials can be used for the development of proton-conducting membranes for fuel cells.

Application of Sol-Gels for Treatment of Gynaecological Conditions-Physiological Perspectives and Emerging Concepts in Intravaginal Drug Delivery.

Approaches for effective and sustained drug delivery to the female reproductive tract (FRT) for treating a range of gynaecological conditions remain limited. The development of versatile delivery platforms, such as soluble gels (sol–gels) coupled with applicators/devices, holds considerable therapeutic potential for gynaecological conditions. Sol–gel systems, which undergo solution-to-gel transition, triggered by physiological conditions such as changes in temperature, pH, or ion composition, offer advantages of both solution- and gel-based drug formulations. Furthermore, they have potential to be used as a suitable drug delivery vehicle for other novel drug formulations, including micro- and nano-particulate systems, enabling the delivery of drug molecules of diverse physicochemical character. We provide an anatomical and physiological perspective of the significant challenges and opportunities in attaining optimal drug delivery to the upper and lower FRT. Discussion then focuses on attributes of sol–gels that can vastly improve the treatment of gynaecological conditions. The review concludes by showcasing recent advances in vaginal formulation design, and proposes novel formulation strategies enabling the infusion of a wide range of therapeutics into sol–gels, paving the way for patient-friendly treatment regimens for acute and chronic FRT-related conditions such as bacterial/viral infection control (e.g., STDs), contraception, hormone replacement therapy (HRT), infertility, and cancer.

1,2-Disubstituted 1,2-Dihydro-1,2,4,5-tetrazine-3,6-dione as a Dynamic Covalent Bonding Unit at Room Temperature.

Dynamic covalent bonds are useful tools in a wide range of applications. Although various reversible chemical reactions have been studied for this purpose, the requirement for harsh conditions, such as high temperature and low or high pH, to activate generally stable covalent bonds limits their potential applications involving biomolecules or household utilization. Here, we report the design, synthesis, characterization, and dynamic covalent bonding properties of 1,2-disubstituted 1,2-dihydro-1,2,4,5-tetrazine-3,6-dione (TETRAD). Hetero-Diels-Alder reactions of TETRAD with furan derivatives and their retro-reactions proceeded rapidly at room temperature under neutral conditions, enabling a chemically induced sol-gel transition system.

Ultrasmall Ag clusters in situ encapsulated into Silicalite-1 zeolite with controlled release behavior and enhanced antibacterial activity

Effectively controlling the release behavior of silver bactericide to promote its antibacterial ability is highly important in the fields of chemical, biomedical and biotechnology industry. In this study, ultrasmall Ag clusters were successfully encapsulated into silicalite-1 zeolite through in situ hydrothermal approach, and the key to this success was choosing 3-mercaptopropyltriethoxysilane as ligand to facilitate Ag precursor involved into zeolite initial sol-gel system. The structure of prepared silicalite-1 zeolite encapsulation of Ag clusters (denoted as Ag@Silicalite-1) has been well defined with various characterizations and probe reactions. Benefiting from confinement effect and shape-selectivity of silicalite-1 zeolite, Ag@Silicalite-1 sample showed much better Ag + controlled release performance than that of sample with Ag nanoparticles impregnated onto silicalite-1 zeolite (denoted as Ag/Silicalite-1). The release behavior of Ag + in Ag@Silicalite-1 can be well described with ritger-peppas model. Taking killing Escherichia coli as an example, in comparison with Ag/Silicalite-1, Ag@Silicalite-1 sample displayed more efficient and sustainable antibacterial activity for its controlled release character. • Ultrasmall Ag clusters were successfully in situ encapsulated into silicalite-1 zeolite. • Encapsulated Ag clusters displayed interesting controlled release behavior and well anti-poisoning property. • Silicalite-1 encapsulated Ag clusters showed sustainable and efficient antibacterial activity.