Physical Adsorption Method Research Articles

Anomalous enhancement of humid CO2 capture by local surface bound water in polar carbon nanopores

Removal of confined space carbon dioxide (CO2) that is in low concentration and with coexisting water is necessary but challenging by physical adsorption method. To make the removal process effective, rendering the nanopore surface hydrophobic to resist water is the popular way. Instead of preventing water from occupying the nanopores, in this work, we propose to utilize the guest water for the spatially selective formation of local surface bound water and further induce the preferential CO2 capture. We observe an anomalous enhancement of CO2 capture performance under humid conditions over carbon nanopores with spatially selective polar sites. It is evidenced that the surface bound water is formed at non-CO2-selective areas of polar carbon nanopores, thus creating additional CO2 trapping sites. This work may inspire the design of environment tolerable materials for molecular separation and purification under harsh conditions.

Naphthalene Monoanhydride and Perylene Composites for Efficient Photocatalytic Hydrogen Evolution and Metal-Free Heterogeneous Oxidative Amidation.

This study explores the synthesis of two visible light active organic chromophore-based composites using naphthalene monoanhydride (Np) and 1,7-dibromoperylene monoanhydride diester (PMDE). These chromophores feature favorable optical and electronic properties and polyaromatic skeletons with anhydride functionalities that facilitate π-π interactions between the chromophore and polymeric carbon nitride (CN) or covalent connections of chromophores with NH2 groups of CN. Accordingly, heterogeneous chromophore-CN composite photocatalysts namely, Np/CN(c) and PMDE/CN(c) were prepared by adopting in situ calcination (c) and composites Np/CN(a) and PMDE/CN(a) were prepared by ex situ physical adsorption (a) methods. In situ prepared Np/CN(c) and PMDE/CN(c) composites exhibited H2 evolution rates (HER) of 1069 and 705 μmol h-1 g-1, respectively, which are significantly higher than ex situ Np/CN(a) and PMDE/CN(a) composites with HER of 465 and 252 μmol h-1 g-1, respectively. These rates are 10, 7, 4.8, and 2.5 times higher than the bulk-CN, indicating the potential of these composites for efficient photocatalytic H2 evolution. Surface area normalized HER enhancements were 3.8, 5.3, 6.6, and 4.2 times higher for Np/CN(c), PMDE/CN(c), Np/CN(a), and PMDE/CN(a) respectively compared to bulk-CN. These composite photocatalysts exhibited excellent stabilities under prolonged photoirradiation, with H2 evolution consistently increasing with the light exposure time. Additionally, these metal-free heterogeneous composites demonstrated efficient photocatalytic activities towards oxidative amidation of aromatic aldehydes, with up to 80% product yields, establishing the prospects of combining homogeneous and heterogeneous entities in a metal-free active material in solar energy harvesting.

Mycotoxin Detection through Colorimetric Immunoprobing with Gold Nanoparticle Antibody Conjugates.

Driven by their exceptional optical characteristics, robust chemical stability, and facile bioconjugation, gold nanoparticles (AuNPs) have emerged as a preferred material for detection and biosensing applications in scientific research. This study involves the development of a simple, rapid, and cost-effective colorimetric immuno-sensing probe to detect aflatoxin B1 and zearalenone using AuNP antibody (AuNP-mAb) conjugates. Anti-toxin antibodies were attached to the AuNPs by using the physical adsorption method. The colorimetric immunosensor developed operates on the principle that the optical properties of the AuNP are very sensitive to aggregation, which can be induced by a critical high salt concentration. Although the presence of antibodies on the AuNP surface inhibits the aggregation, these antibodies bind to the toxin with higher affinity, which leads to exposure of the surface of AuNPs and aggregation in a salt environment. The aggregation triggers a noticeable but variable alteration in color from red to purple and blueish gray, as a result of a red shift in the surface plasmon resonance band of the AuNPs. The extent of the shift is dependent on the toxin exposure dose and can be quantified using a calibration curve through UV-Visible-NIR spectroscopy. The limit of detection using this assay was determined to be as low as 0.15 ng/mL for both zearalenone and aflatoxin B1. The specificity of the prepared immunoprobe was analyzed for a particular mycotoxin in the presence of other mycotoxins. The developed immunoprobe was evaluated for real-world applicability using artificially spiked samples. This colorimetric immunoprobe based on localized surface plasmon resonance (LSPR) has a reduced detection limit compared to other immunoassays, a rapid readout, low cost, and facile fabrication.

Immunochromatographic Strip Based on Tetrahedral DNA Immunoprobe for the Detection of Aflatoxin B1 in Rice Bran Oil.

Aflatoxin B1 (AFB1), a widespread contaminant in food and feeds, poses a threat to the health of animals and humans. Consequently, it is significant to develop a rapid, precise and highly sensitive analytical method for the detection of AFB1. Herein, we developed an immunochromatographic strip (ICS) based on a tetrahedral DNA (TDN) immunoprobe for AFB1 determination in rice bran oil. Three sizes of TDN immunoprobes (AuNP-TDN13bp-mAb, AuNP-TDN17bp-mAb, AuNP-TDN26bp-mAb) were constructed, and the performance of these three immunoprobes, including the effective antibody labeling density and immunoaffinity, was measured and compared with that of the immunoprobe (AuNP-mAb) developed using the physical adsorption method. Subsequently, the optimal TDN immunoprobe, namely AuNP-TDN13bp-mAb, was selected to prepare the immunochromatographic strip (ICS) for the qualitative and quantitative detection of AFB1 in rice bran oil. The visual limits of detection (vLODs) of the ICS based on AuNP-TDN13bp-mAb and AuNP-mAb were 0.2 ng/mL and 2 ng/mL, with scanning quantitative limits (sLOQs) of 0.13 ng/mL and 1.4 ng/mL, respectively. The ICS demonstrated a wide linear range from 0.02 ng/mL to 0.5 ng/mL, with good specificity, accuracy, precision, repeatability, and stability. Moreover, a high consistency was observed between the constructed ICS and ultra-high-performance liquid chromatography (UPLC) in the quantification of AFB1. The results indicated that the introduction of TDN was beneficial for promoting efficient antibody labeling, protecting the bioactivity of immunoprobes, and increasing the sensitivity of detection, which would provide new perspectives for the achievement of the highly sensitive detection of mycotoxins.

Pyrolytic Decomposition of Polyethylene in the Presence of Aluminosilicate Materials Containing Nickel Oxide

The work is devoted to the study of the pyrolysis of high-density polyethylene (PE) in the presence of aluminosilicate materials containing nickel oxide. The process of catalytic pyrolysis of plastics makes it possible to convert polymers into chemical compounds, which can later be used as an additional source of fuels, raw materials for the chemical industry or polymer production. The physicochemical parameters of materials containing nickel oxide have been established using the following methods: IR-Fourier spectroscopy; x-ray diffraction analysis; N2 physical adsorption method; thermogravimetric analysis; pyrolytic gas chromatography. The dependences of the chemical composition of PE pyrolysis products on the type of support used and the presence of nickel oxide. The presence of nickel oxide in the studied aluminosilicates increases the Lewis acidity, which increases the content of aromatic compounds in the pyrolysis products. The activation energy of the PE pyrolysis process in the presence of MCM-41 containing nickel oxide was calculated from experimental data.

Innovative dodecane-hexadecane/expanded graphite composite phase change material for sub-zero cold storage applications

Utilization of phase change materials (PCMs) for cold energy storage has garnered increasing attention. This study focuses on the development of a composite PCM by integrating a novel eutectic dodecane-hexadecane (DD-HD) PCM into expanded graphite (EG), to cater to the demands of sub-zero cold energy storage applications, such as cold chain logistics. The study identified the optimal mass ratio of DD-HD as 80:20. A series of DD-HD/EG composites were fabricated through a combination of high-speed emulsification and physical adsorption methods. The adsorption capacity of EG for the eutectic PCM mixture was evaluated by examining the impact of EG fraction on the leakage of the composite PCM, revealing that the optimum EG fraction is 10 wt%. The composite PCM displayed a sub-zero phase change temperature of -12.09 ℃, a high melting enthalpy of 178.75 kJ/kg, and a high thermal conductivity of 5.18 W/(m•K). The thermal conductivity of the composite was enhanced by 22.52 times compared to the base PCM. Thermogravimetric analysis indicated that the decomposition temperature of DD-HD/EG was significantly higher than that of the base PCM. The composite demonstrated outstanding thermal reliability, as evidenced by thermal cycle tests. With its impressive thermal characteristics, this composite shows great potential for various cold energy storage applications.

Experimental study on coagulation and adsorption treatment of wastewater in combustion cavity for underground coal gasification

Underground Coal Gasification (UCG) is a promising mineral resource development technology that can transform in-situ coal into combustible gas by controlling combustion. However, wastewater generated during the UCG process can lead to environmental pollution in adjacent areas through diffusion or infiltration. In order to seek an efficient and inexpensive in-situ treatment method for underground gasification combustion zone wastewater, UCG model experiments were conducted to obtain wastewater, and the treatment effects of chemical coagulation and physical adsorption methods were compared in this work. The COD concentration in wastewater from underground combustion zone ranges between 555 ∼ 703 mg/L, with a pH value between 8.26 ∼ 8.85. The organic pollutants mainly come from the dissolution of high carbon components, mainly aromatic compounds in tar, which leads to high toxicity and pollution risk of wastewater. For chemical coagulation method, the removal effect of organic pollutants in combustion zone wastewater by ferric sulfate is better than that of aluminum sulfate due to excellent hydrolysis reaction of Fe3+. The corresponding COD removal rate and COD removal cost are 24.34 % and 0.176 ¥/g, respectively. For physical adsorption method, due to the large total pore volume and wide specific surface area of organic bentonite, it can effectively remove COD content. The COD removal rate and COD removal cost, and COD adsorption capacity are 60.23 %, 0.213 ¥/g, and 89.75 mg/g, respectively. Comprehensive comparison shows that physical adsorption is more suitable for in-situ treatment of combustion zone wastewater.

Thermal and photo/electro-thermal conversion characteristics of high energy storage density expanded graphite/polyethylene glycol shaped composite phase change materials

Compared with other energy storage materials, phase change materials (PCMs) are drawing widespread attention because of their high enthalpy and low temperature change. However, its low thermal conductivity, low photo/electro-thermal conversion characteristics, phase separation and easy leakage are still urgent problems. In this work, expanded graphite/polyethylene glycol (EG/PEG) composites were prepared based on physical adsorption method, the relationship between the mass percentage of EG and the microstructure, phase transition properties (phase change enthalpy, supercooling degree) and energy conversion properties was studied. The composite PCM exhibits exceptional thermal conductivity (2.48 W·m−1·K−1, 7 folds greater than that of PEG) and outstanding melting enthalpy (161.4 J/g). The thermal conductivity of the EG/PEG composites is almost constant versus temperature over measured temperature range (26 ℃∼60 ℃). The energy conversion capacities (photo/electro-thermal conversion) increase as the expanded graphite mass fraction increases. The prepared composite PCM obviously overcomes the shortcomings of the pure polyethylene glycol, and highlights enormous application in the domains of multi-physical energy conversion and premium quality power absorption.

Redox-Active Phenanthrenequinone Molecules and Nitrogen-Doped Reduced Graphene Oxide as Active Material Composites for Supercapacitor Applications.

Carbon-based supercapacitor electrodes are generally restricted in energy density, as they rely exclusively on electric double-layer capacitance (EDLC). The introduction of redox-active organic molecules to obtain pseudocapacitance is a promising route to develop electrode materials with improved energy densities. In this work, we develop a porous nitrogen-doped reduced graphene oxide and 9,10-phenanthrenequinone composite (N-HtrGO/PQ) via a facile one-step physical adsorption method. The electrochemical evaluation of N-HtrGO/PQ using cyclic voltammetry showed a high capacitance of 605 F g-1 in 1 M H2SO4 when the composite consisted of 30% 9,10-phenanthrenequinone and 70% N-HtrGO. The measured capacitance significantly exceeded pure N-HtrGO without the addition of redox-active molecules (257 F g-1). In addition to promising capacitance, the N-HtrGO/30PQ composite showed a capacitance retention of 94.9% following 20,000 charge/discharge cycles. Based on Fourier transform infrared spectroscopy, we postulate that the strong π-π interaction between PQ molecules and the N-HtrGO substrate enhances the specific capacitance of the composite by shortening pathways for electron transfer while improving structural stability.

Evaluation of chlorophyll-loaded mesoporous silica nanoparticles for photodynamic therapy on cancer cell lines

Chlorophyll (Chl) is a promising natural photosensitizer (PS) in photodynamic treatment (PDT). Mesoporous silica nanoparticles (MSNs) were chosen to increase the effectiveness of PDT. This study aimed to evaluate the synergistic efficacy of chlorophyll-loaded mesoporous silica nanoparticles (Chl-MSNs) with photodynamic therapy (PDT) and to investigate their potential toxicity in HepG2, MDA-MB-231, and HSF cell lines. Chl-MSNs were prepared via the physical adsorption method. TEM, DLS, and zeta potential examined morphology, size, and surface characteristics. MSNs and Chl-MSNs were characterized using the same techniques. HPLC was used to assess the encapsulation efficiency. At pH 7.4, an in vitro release experiment of Chl-MSNs was performed. Chl, MSNs, and Chl-MSNs were applied to the three cell lines at different concentrations and subjected to red (650 nm) and blue (450–500 nm) lasers. MSNs and Chl-MSNs’ sizes were 90.338 ± 38.49 nm and 123.84 ± 15.67 nm, respectively, as obtained by TEM; the hydrodynamic diameter for MSNs (93.69 ± 20.53 nm) and Chl-MSNs (212.95 ± 19.76 nm); and their zeta potential values are − 16.7 ± 2.19 mV and − 18.84 ± 1.40 mV. The encapsulation efficiency of Chl-MSNs was 70%. Chl-MSNs displayed no toxicity in dark conditions but showed excellent photostability under blue and red light exposure. Furthermore, using Chl over Chl-MSNs has a higher PDT efficiency than the tested cell lines. Chl-MSNs have the potential to be an effective delivery system. PDT proved to be an essential technique for cancer treatment. Blue laser is recommended over red laser with Chl and MSNs for destroying cancer cells.Graphical

One-Pot Assembly of Drug-Eluting Silk Coatings with Applications for Nerve Regeneration.

Clinical use of polymeric scaffolds for tissue engineering often suffers from their inability to promote strong cellular interactions. Functionalization with biomolecules may improve outcomes; however, current functionalization approaches using covalent chemistry or physical adsorption can lead to loss of biomolecule bioactivity. Here, we demonstrate a novel bottom-up approach for enhancing the bioactivity of poly(l-lactic acid) electrospun scaffolds though interfacial coassembly of protein payloads with silk fibroin into nanothin coatings. In our approach, protein payloads are first added into an aqueous solution with Bombyx mori-derived silk fibroin. Phosphate anions are then added to trigger coassembly of the payload and silk fibroin, as well as noncovalent formation of a payload-silk fibroin coating at poly(l-lactic) acid fiber surfaces. Importantly, the coassembly process results in homogeneous distribution of protein payloads, with the loading quantity depending on payload concentration in solution and coating time. This coassembly process yields greater loading capacity than physical adsorption methods, and the payloads can be released over time in physiologically relevant conditions. We also demonstrate that the coating coassembly process can incorporate nerve growth factor and that coassembled coatings lead to significantly more neurite extension than loading via adsorption in a rat dorsal root ganglia explant culture model.

Pollution-free interface of 2D-MoS2/1D-CuO vdWs heterojunction for high-performance photodetector

Van der Waals heterostructures provide a new opportunity for constructing new structures and improving the performance of electronic and optoelectronic devices. However, the existing methods of constructing heterojunctions are still faced with problems such as impurity introduction, or complex preparation process and limited scope of application. Herein, a physisorption method is proposed to composite CuO nanorods on the surface of MoS2 nanosheets. CuO nanorods and MoS2 form type-Ⅱ heterojunctions, which promotes the separation and transport of photo-generated charge carriers. More importantly, compared with the transfer and coating methods, the physical adsorption method avoids the introduction of auxiliary materials during the whole process of constructing the heterojunction, and therefore effectively reduces the damage and pollution at the interface. The optimized MoS2/CuO heterojunction photodetector achieves a high photoresponsivity of ∼680.1 A W−1 and a fast response speed of ∼29 μs. The results demonstrate that the physisorption method provides a feasible approach to realize high performance photodetectors with pollution-free interfaces, and it can also be extended to the development of other low-dimensional hybrid heterojunction electronic and optoelectronic devices.

3D-printed monolithic ZSM-5@nano-ZSM-5: Hierarchical core-shell structured catalysts for enhanced cracking of polyethylene-derived pyrolysis oils

The catalytic upgrading of polyethylene-derived pyrolysis oils using ZSM-5 zeolites enables the cost-effective production of valuable chemicals from plastic waste, fostering a circular economy through resource recycling. To achieve high-performance catalyst design, balancing active site accessibility and selectivity is crucial. Here, we report a monolithic ZSM-5 @nano-ZSM-5 core-shell catalyst (mZ@nZ) fabricated via vat photopolymerization, in situ crystal engineering, and a one-step desilication-recrystallization treatment. The micromorphologies and microstructures of the core-shell catalysts are investigated using electron microscopies and physical adsorption methods. The mZ@nZ catalyst features a self-supporting face-centered cubic macrostructure with a layer of compositionally heterogeneous ZSM-5 zeolites, which comprises a catalytically benign nano-ZSM-5 shell (Si-rich) and a catalytically active ZSM-5 core (Al-rich). Abundant mesopores are created in mZ@nZ through desilication and zeolite agglomeration processes. This design offers three significant advantages: (1) enhanced active site accessibility via in situ zeolite growth, (2) surface passivation using a Si-rich shell to minimize side reactions, and (3) improved diffusion facilitated by the hierarchical structure, reducing light olefin secondary reactions and coke formation. Compared to pristine monolithic ZSM-5 and a reference pelletized catalyst, the mZ@nZ catalyst demonstrates superior performance in terms of higher light olefin yields and selectivities, with enhanced resistance to coking in the model compound and real LDPE pyrolysis oil cracking reactions. This research showcases a rational design approach at both macroscopic and microscopic scales, offering valuable insights for advancing polyolefin waste upgrading and novel zeolite catalyst design.

Hydroxyapatite-based nano-drug delivery system for nicotinamide mononucleotide (NMN): significantly enhancing NMN bioavailability and replenishing in vivo nicotinamide adenine dinucleotide (NAD+) levels.

This study addresses the bioavailability challenges associated with oral nicotinamide mononucleotide (NMN) administration by introducing an innovative NMN formulation incorporated with hydroxyapatite (NMN-HAP). The NMN-HAP was developed using a wet chemical precipitation and physical adsorption method. To assess its superiority over conventional free NMN, we examined NMN, nicotinamide adenine dinucleotide (NAD+), and nicotinamide riboside (NR) levels in mouse plasma and tissues following oral administration of NMN-HAP. NMN-HAP nanoparticles demonstrated a rod-shaped morphology, with an average size of ~50 nm, along with encapsulation efficiency and drug loading capacity exceeding 40%. In vitro, drug release results indicated that NMN-HAP exhibited significantly lower release compared with free NMN. In vivo studies showed that NMN-HAP extended circulation time, improved bioavailability compared with free NMN, and elevated plasma levels of NMN, NAD+, and NR. Moreover, NMN-HAP administration displayed tissue-specific distribution with a substantial accumulation of NMN, NAD+, and NR in the brain and liver. NMN-HAP represents an ideal formulation for enhancing NMN bioavailability, enabling tissue-specific delivery, and ultimately elevating in vivo NAD+ levels. Considering HAP's biocompatible nature and versatile characteristics, we anticipate that this system has significant potential for various future applications.

Highly sensitive determination of putrescine in pork by an electrochemical biosensor constructed with unfolded hemoglobin and diamine oxidase

Based on the principle that diamine oxidase (DAO) catalyzes putrescine to produce H2O2 and unfolded hemoglobin (uHb) has the good catalytic ability to H2O2, a highly sensitive electrochemical biosensor for the determination of putrescine was constructed. The biosensor was prepared through immobilizing uHb on the surface of clay modified glassy carbon electrode (GCE) by physical adsorption method, and then using 2.5% glutaraldehyde as cross-linking agent to fix DAO. In order to achieve the best results, the concentration of DAO, the type of peroxidase, the stability of modified electrode and the test conditions were optimized. Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) were used to characterize the preparation process of the sensor. Under the optimized conditions, the difference of reductive peak currents had good linear relationships with putrescine concentration in the ranges of 1.0 × 10−11-1.0 × 10−10 mol L−1 and 1.0 × 10−10-1.0 × 10−9 mol L−1 (r ≥ 0.997), respectively. The limit of detection (LOD) was 3.3 × 10−12 mol L−1 (S/N = 3). The developed electrochemical biosensor had good reproducibility, stability and sensitivity, and was successfully applied for the determination of putrescine in real pork samples.

Synthesis of magnetite-silica-carbon quantum dot nanocomposites for melatonin drug delivery

In targeted drug delivery, the drug is released at a specific and desired point and condition. In this research, magnetite cores (high saturation magnetization property (emu.g-159) were used to target the drug system. First, magnetite nanoparticles were synthesized by coprecipitation method from divalent and trivalent chloride salts of iron (FeCl2 and FeCl3), then mesoporous silicas (with a pore diameter of 13 nm) were formed by Stöber's method from the tetraethylorthosilicate (TEOS) silica source on magnetite cores in spheres form. After that, the carbon quantum dots were synthesized by hydrothermal method from citric acid and their surface was immobilized by dimethylamine which were placed in silica cavities by physical adsorption method.
 The effective drug melatonin (6.46 mg of melatonin per 100 mg of the drug system) was also loaded on this system by physical absorption method and the release of this drug was carefully determined by the release from the dialysis bag in the simulated environment of blood and cancer tissue. the quantum gain of the system was determined to be about 40%. The results showed that the loading of melatonin drug and carbon quantum dots was done well on silica nanoparticles with magnetite cores, and this system releases 30% of the drug even under temperature conditions.

Effects of micro-mesopore structure characteristics on methane adsorption capacity of medium rank coal

The relationship between micro-mesoporous structure characteristics and gas adsorption capacity of medium-rank coal under different particle sizes was studied by physical adsorption method. The results showed that the capacity of adsorption nitrogen and carbon dioxide, specific surface area (SSA), BET SSA and micropore volume all increased with the decrease of particle size. The range of mesoporous aperture measured by BJH method was larger than that by DFT method, but the pore volume (PV) and SSA are relatively lower, which confirmed that the BJH method will underestimate part of the aperture. However, there was blank bands in the measurement of pore size in 2–4 nm by DFT method, which will also reduce the real value. The limiting gas adsorption volumes of 1#, 2#, 3# and 4# coal samples under different particle sizes were 17.19–20.76 m3/t, 14.11–19.3 m3/t, 17.17–19.14 m3/t and 12.11–15.59 m3/t, respectively, and the results gradually increased with the decrease of particle size. The linear correlation between BET SSA, mesoporous PV and Langmuir volume of coal was 0.43, 0.5–0.53 and 0.37–0.5, respectively, which was relatively low on the whole and slightly lower than the results in the literature. The linear correlation between Langmuir volume and micropore volume and SSA was 0.73 and 0.76, respectively, which was higher than mesoporous structure parameters and BET SSA. The control effect of microporous structure parameters on gas adsorption was significantly higher than mesoporous structure and BET SSA. The error between the calculated limit gas adsorption volume and the experimental limit gas adsorption volume was small, and the proportion of the microporous filling limit gas adsorption volume was as high as 99.7%. Multiple studies have proved that micropore is the main space of gas adsorption.

Investigation of Antimicrobial Effects of Polydopamine-Based Composite Coatings.

Herein, polydopamine (PDA)-based antimicrobial coatings loaded with silver nanoparticles (Ag NPs) and gentamicin were designed and prepared on glass slides using two different approaches. To our knowledge, this study was performed for the first time with the aim to compare these methods (viz., in situ loading and physical adsorption method) regarding the loading and release behavior of payloads. In one method, gentamicin was in situ loaded on PDA-coated substrates during PDA polymerization followed by Ag NPs immobilization (named as Ag@Gen/PDA); for the second method, Ag NPs and gentamicin were simultaneously loaded onto PDA via physical adsorption by immersing pre-formed PDA coatings into a mixed solution of Ag NPs and gentamicin (named as Ag/Gen@PDA). The loading and release characteristics of these antimicrobial coatings were compared, and both gave variable outcomes. The in situ loading method consequently provided a relatively slow release of loaded antimicrobials, i.e., approx. 46% for Ag@Gen/PDA as compared to 92% from physically adsorbed Ag/GenPDA in an immersion period of 30 days. A similar trend was observed for gentamicin release, i.e., ~0.006 µg/mL from Ag@Gen/PDA and 0.02 µg/mL from Ag/Gen@PDA each day. The slower antimicrobial release from Ag@Gen/PDA coatings would ultimately provide an effective long-term antimicrobial property as compared to Ag/Gen@PDA. Finally, the synergistic antimicrobial activities of these composite coatings were assessed against two microbial species, namely, Staphylococcus aureus and Escherichia coli, hence providing evidence in the prevention of bacterial colonization.

Investigation of adsorption and biosorption features of bio-functionalized poly(GMA-Co-EGDMA) polymer beads in the treatment of nicotine from tobacco industry

The investigation of multifunctional materials for modern enzyme immobilization is an attractive subject in advanced adsorption and biosorption applications. In the present study, the feasibility of immobilization of Lipozyme TL 100L (LPZM) on 3-aminopropyltriethoxysilane (APTES) modified poly-(GMA-co-EGDMA) (PEGDMA) was investigated for adsorption and biosorption of nicotine from aqueous solution. Characterization tests confirmed successful immobilization of lipozyme which significantly altered thermal behavior, surface characteristics, and surface morphology of PEGDMA and PEGDMA/APTES. In addition, the immobilization yields were calculated as 85.0% and 72.0% onto PEGDMA/APTES using physical adsorption and covalent immobilization methods, respectively. The nicotine removal efficiencies were calculated to be 66.4%, 79.0%, 98.9%, and 85.7%, using raw PEGDMA, PEGDMA/APTES, PEGDMA/APTES@LPZM, and PEGDMA/APTES/GU@LPZM, respectively. For the raw PEGDMA, the Langmuir isotherm was best fitted to the adsorption data, while Langmuir-Freundich model described well the adsorption process on PEGDMA/APTES and PEGDMA/APTES@LPZM. The maximum adsorption capacities of Langmuir-Freundlich model increased from 8.118 to 17.32mg/g after enzyme immobilization. The negative enthalpy value, ΔH° (- 10.37kJ/mol), revealed that the nicotine adsorption on PEGDMA/APTES@LPZM was exothermic in nature, which was corroborated by the decrease observed in the number of adsorbed molecules with increasing temperature. In the kinetic experiments, the adsorption on PEGDMA and PEGDMA/APTES@LPZM reached equilibrium with the removal percentages as 66.4% and 98.9% at the end of 3h, respectively. The nicotine adsorption performances in real water matrices were also investigated, and PEGDMA/APTES@LPZM showed satisfactory reusability with removal percentage decreased from 98.9% (1st cycle) to 83.0% (6th cycle).

Porphyrin-based porous organic polymer coated ZIF-8 nanoparticles as tumor targeted photosensitizer for combination cancer photodynamic/photothermal therapy

The issue of low tumor-targeting and easy aggregation of small-molecule photosensitizers (PSs), as well as the heterogeneity and complexity of tumor tissue, greatly limit the therapeutic efficiency of phototherapy. Herein, a porphyrin-based organic polymer (POP) coated zeolitic imidazolate framework-8 (ZIF-8) hybrid nanoparticles (POP@ZIF-8) was developed, for delivering photosensitizer (porphyrin-based POP) specifically into tumor sites. The low-cost, biocompatible, tumor-specific POP@ZIF-8 with core-shell structure was prepared via a simple but efficient covalent surface-coating strategy, in which the pH-responsive ZIF-8 functioned as templates, finely controlling the nanometer size of the hybrid and ensuring targeted delivery of PSs to tumor tissue. Moreover, a direct covalently coated polymer-based PSs on ZIF-8 can better preserve optical properties compared to conventional physical adsorption methods. Under laser irradiation, the resulting hybridization not only efficiently converts light into local heat, causing severe photothermal damage to tumor tissue, but also synergistically promotes the production of strongly toxic 1O2, which exerts a photodynamic treatment on tumor sites. Therefore, this special POP@ZIF-8 hybrid presented a cooperatively enhanced synergistic photodynamic/photothermal anticancer efficacy, as demonstrated both the in vitro and in vivo assay, systematically. This study presents a practicable and reliable strategy to develop stable and high-efficiency cancer phototherapy agents which could simultaneously manipulate the structural characteristics and performance of targeted materials for promising noninvasive multi-mode anti-cancer.