Cross-linking Ratio Research Articles

Dynamics of Hydrogels with a Variable Ratio of Permanent and Transient Cross-Links: Constitutive Model and Its Molecular Interpretation

Dynamics of Hydrogels with a Variable Ratio of Permanent and Transient Cross-Links: Constitutive Model and Its Molecular Interpretation

Adsorption of rutin from olive mill wastewater using copolymeric hydrogels based on N-vinylimidazole: Kinetic, equilibrium, and thermodynamics assessments

Olive mill wastewater, also known as olive wastewater, contains biologically active components with various beneficial effects on health. The development of novel adsorbent materials for the recovery of these biologically active substances is important area of research. In this study, copolymeric hydrogels based on N-vinylimidazole (VIm), a new material that has never been used as an adsorbent in the separation of phenolic components, were synthesized. The hydrogels synthesized in this study is copolymer structures based on N-vinylimidazole (VIm) containing [2- (methacryloxy) ethyl] dimethylpentylammonium bromide (QDMAC5) in different moles. QDMAC5 was obtained by quaternization of 2- (dimethylamino) ethyl methacrylate (DMA) with 1-bromopentane (C5). The production of copolymer hydrogels was carried out by free radical solution polymerization. The syntheses were carried out only by changing the monomer composition so that the crosslinker ratio remained constant (1.2 mol%). The QDMAC5 content in the copolymers was 5, 10, 20, 30, and 50 mol%. So, the resulting structures were named PVQ-5%, PVQ-10%, PVQ-20%, PVQ-30%, and PVQ-50%, respectively. Functional group characterizations of hydrogels were made by Fourier Transform Infrared Spectrometry (FTIR). The surface of the hydrogels was analyzed by Scanning Electron Microscopy (SEM). Finally, thermogravimetric analyzes (TGA) were performed to investigate the thermal degradation behavior. The recovery of the rutin present in olive mill wastewater has been investigated as a model study. Kinetic data has been represented by the selected models (pseudo-first order, pseudo-second order, and intraparticle diffusion) convincingly (R2 > 0.76), while the equilibrium findings have fitted well to Langmuir, Freundlich, and Temkin equations (R2 > 0.77). Rutin adsorption process on N-vinylimidazole (VIm) based copolymeric hydrogels has been found as exothermic and spontaneous chemisorption process depending on the thermodynamic analysis.

Preparation and properties of ZnMoO4 anode materials with polymer network gel method

Polymer network gel method combines the advantages of solid-phase method and liquid phase method, triggering acrylamide (AM) radical polymerization in aqueous solution and N, N′- methylene bis acrylamide (MBAM) active double bond cross-linking reaction, forming polymer chains to form a three-dimensional network. The polymer network space formed by the gel is bound and evenly distributed to the ions in the solution, thereby reducing the contact and aggregation of molecules and achieving the purpose of uniform particle size and small particle size. The principle diagram of network gel is shown in Figure. Using cubic zinc acetate and ammonium molybdate tetrahydrate as raw materials, cubic ZnMoO4 negative electrode materials were prepared with polymer network gel method. The polymer network gel method has various effects on the structure, morphology and electrochemical properties of materials. Besides, the calcination temperature and calcination time were also the key factors to the electrochemical properties of the materials. In this paper, the effects of the ratio of monomer and crosslinker, calcination temperature and calcination time on ZnMoO4 materials were studied by single variable method, the preparation process was optimized, and its characterization and electrochemical tests were carried out. After 100 cycles, the optimized ZnMoO4 electrode has a discharge capacity of 374.0 mAh· g−1, 332.5, 263.5 and 177.1 mAh · g−1 at current densities of 0.1, 0.5, 1.0 and 2.0 A g−1, respectively. The electrochemical results show that the optimized ZnMoO4 has high capacity, large rate capability and excellent cycle stability.

Surface channel patterned and endothelialized poly(glycerol sebacate) based elastomers.

Prevascularization of tissue equivalents is critical for fulfilling the need for sufficient vascular organization for nutrient and gas transport. Hence, endothelial cell culture on biomaterials is of great importance for researchers. Numerous alternate strategies have been suggested in this sense, with cell-based methods being the most commonly employed. In this study, poly (glycerol sebacate) (PGS) elastomers with varying crosslinking ratios were synthesized and their surfaces were patterned with channels by using laser ablation technique. In order to determine an ideal material for cell culture studies, the elastomers were subsequently mechanically, chemically, and biologically characterized. Following that, human umbilical vein endothelial cells (HUVECs) were seeded into the channels established on the PGS membranes and cultured under various culture conditions to establish the optimal culture parameters. Lastly, the endothelial cell responses to the synthesized PGS elastomers were evaluated. Remarkable cell proliferation and impressive cellular organizations were noticed on the constructs created as part of the investigation. On the concrete output of this research, arrangements in various geometries can be created by laser ablation method and the effects of various molecules, drugs or agents on endothelial cells can be evaluated. The platforms produced can be employed as an intermediate biomaterial layer containing endothelial cells for vascularization of tissue-engineered structures, particularly in layer-by-layer tissue engineering approaches.

Polysulfide Synthesis Using Waste Cooking Palm Oil via Inverse Vulcanization

AbstractElemental sulfur and waste cooking palm oil (WCO) are abundant industrial by‐products from petrochemical and food processing industries, respectively. WCO was used as a crosslinker to prepare a high‐sulfur‐content polymer through inverse vulcanization. Polysulfides were generated under vigorous stirring of WCO with elemental sulfur at different temperatures, crosslinking ratios, and reaction times. The physicochemical properties of the produced polysulfides were determined and the thermal stability was analyzed. The FTIR spectra including the breakdown of C=C and formation of C–S bond confirmed the change of functional groups between WCO and produced polymer. The effect of saturated and unsaturated triglycerides of WCO is clearly visible in SEM micrographs. The polysulfide with a 70 wt % sulfur feed ratio showed excellent morphological and thermal properties.

Effect of Cold Plasma Treatment, Cross‐Linking, and Dual Modification on Corn Starch

AbstractCorn starch has limited applications due to its paste intolerance during heating, high shear processing, and low pH of foods. In this study, native corn (NC) starch is treated by both cold plasma and chemical cross‐linking to produce modified starch. The cross‐link ratio (CR), granule morphology, as well as other physicochemical properties of the modified starch are evaluated. The CR is 5.2% by plasma treatment, and it could be further increased up to 23.7% by the subsequent cross‐linking using adipic acid and acetic acid anhydride mixture. Modified granules have more cracks, pits, holes, and damages than NC ones. FTIR spectra's shows some new peaks after dual modification (1563 cm−1) and plasma treatment (1730 cm−1). The plasma and cross‐linking treatments cause a significant increase of swelling power for all the modified starches. Results of the present study indicate the possibilities of exploring cold plasma and cross‐linking treatments for starch modifications.

Mechanochemical characteristics and influence mechanisms of a biomass hydrogel artificial muscle based on different parameters of the sodium alginate adjustment

Biomass hydrogel artificial muscle (BHAM) is a kind of ionic electroactive polymers, such as ionic polymer gels of good biocompatibility and stimulus responsiveness under electric field, which is largely used in the fields of soft robots and electric actuators. In this paper, based on the freeze-drying process, effect and influence mechanisms of sodium alginate (SA) parameters adjustment on the BHAM mechanochemical characteristics were researched extensively, which was verified by a set of perfect characteristic evaluation and experimental test methods, such as the porosity P (v%), water retention rate W r (w%), mechanochemical property testing and scanning electron microscope shots. The results showed that when the concentration of SA was 20 g l−1, the actuating film of BHAM had suitable thickness and stomata in macroscopic appearance, and its micro pore distribution and size were uniform with the thin pore wall, which resulted in the highest porosity (i.e. ion channel) of 73.5 v%, the largest water retention rate of 76.2 w% and the optimum tensile strength of 0.38 MPa. Furthermore, calcium chloride (CaCl2) was adopted as a cross-linking agent to react with the SA to form calcium alginate (CA) by different CaCl2 cross-linking ratios, that was to modify the three-dimensional microstructure of the BHAM to improve its mechanical properties with the best deflection displacement of 23.9 mm and bending strain of 3.45% under the ideal CaCl2 cross-linking ratio of 1%. Besides, the diffraction of x-rays analysis and thermal decomposition experiments of the BHAM were performed, which was demonstrated that the thermal stability of the CA-based BHAM was higher than that of the SA-based BHAM.

Technology efficiency and promotion mechanism on the response output performance of a biomimetic gelatinous polymer actuator based on different process approaches

AbstractIn this paper, from different aspects of internal material composition, biomass modification method and assembly process factor of the biomimetic gelatinous polymer actuator (BGPA), its three process approaches including ionic liquid (IL, [EMIm]BF4) doping amount, sodium alginate (SA) ‐ carboxymethyl chitosan (CMCS) crosslinking ratio and casting assembly temperature were comprehensively compared, and accordingly their technology efficiency and promotion mechanism on response output performance of the BGPA had also been fully researched. The results suggested that under monotonic work cycle, when the IL doping amount was 4 ml, operating life of BGPA reached the maximum of 1720 s and its smallest tremor amplitude was 8.51%. When the SA‐CMCS crosslinking ratio was 5:5, all three evaluation indexes of the duty cycle, internal resistance and elastic modulus of BGPA achieved the minima around 0.97%, 1.61 Ω and 0.207 MPa, respectively. When the casting assembly temperature was 50°C, specific capacitance and output force density of the BGPA separately obtained the largest values of 551.34 mF/g and 16.249 mN/g. Within the cycle repetition period, the best stable output force of the BGPA was approximately 2.877 mN with 4 ml ionic liquid, and its optimal electron current was 12.771 mA at 50°C.

The Crosslinker Matters: Vinylimidazole-Based Anion Exchange Polymer for Dispersive Solid-Phase Extraction of Phenolic Acids

Crosslinkers are indispensable constituents for the preparation of SPE materials with ethylene glycol dimethacrylate (EGDMA) and divinylbenzene (DVB) among the most prominent representatives. A crosslinker that has not yet been used for the preparation of SPE sorbents is 3,3’-(hexane-1,6-diyl)bis(1-vinylimidazolium) bromide [C6-bis-VIM] [Br]. In this study, we synthesized differently crosslinked vinylimidazole polymers with EGDMA, DVB and [C6-bis-VIM] [Br] and evaluated their extraction efficiencies towards phenolic acids. Dispersive SPE experiments performed with the [C6-bis-VIM] [Br] crosslinked polymers exhibited significantly higher extraction recoveries for the majority of analytes. Due to these promising results, the [C6-bis-VIM] [Br] crosslinked polymer was optimized in terms of the monomer to crosslinker ratio and an efficient dispersive SPE protocol was developed, with maximum recoveries ranging from 84.1–92.5% and RSD values ˂ 1%. The developed extraction procedure was also applied to cartridges resulting in recoveries between 97.2 and 98.5%, which were on average 5% higher than with the commercial anion exchange sorbent Oasis® MAX. Furthermore, the sorbent was regenerated showing a good reusability for the majority of analytes. In conclusion, this study clearly highlights the yet untapped potential of the crosslinker, [C6-bis-VIM] [Br], with respect to the synthesis of efficient anion exchange polymers for SPE.

Preparation and characterization of Co(II) ion-imprinted composite membrane based on a novel functional monomer

In this paper, a novel functional monomer, N-(pyrrolidin-2-ylmethyl) methacrylamide (PMMA), was synthesized. Using Co(II) ions as the template, 2,2-azoisobutyronitrile (AIBN) as the initiator, ethylene glycol dimethacrylate (EDGMA) as the crosslinking agent, twenty-seven Co(II) ion-imprinted composite membranes (Co(II)-PMMA-IICM 1∼27 ) and their corresponding non-imprinted composite membranes (PMMA-NICM 1∼27 ) were prepared. Additionally, the related parameters of the imprinting system were systematically optimized. Co(II) ion-imprinted composite membranes (Co(II)-PMMA-IICM 16 ) were prepared using Nylon-6 as the supporting membrane, which was soaked in a pre-polymerized solution of N,N-dimethylformamide and water (DMF: H 2 O ( v/v ) = 1: 1) for 180 s, using a molar ratio of template, monomer, and crosslinker of 1: 4: 50. The obtained material had a higher adsorption capacity ( Q e = 428.24 mg g −1 ) and imprinting factor ( IF = 2.36). The surface and internal porosity of Co(II)-PMMA-IICM 16 were characterized by scanning electron microscopy and a nitrogen adsorption apparatus. In addition, it was found that the adsorption process of Co(II)-PMMA-IICM 16 prepared under optimal conditions was better described by a Langmuir isotherm adsorption model, which verified that the adsorption involved monolayer adsorption. The kinetics data was more closely fit by a pseudo-second-order kinetics model, indicating that this adsorption process proceeded via chemisorption. The permeation experiments indicated that a “delayed” permeation mass transfer mechanism also occurred ( β (Co(II)/Cd(II)) = 2.11 and β (Co(II)/Cu(II)) = 1.55). The Co(II) ion-imprinted composite membrane prepared in this paper demonstrated a relatively better imprinting effect, a specific recognition ability for template ions, and good selective permeability. These results validated that the design of this novel functional monomer was reasonable, and that it has potential applications in various fields where adsorption is necessary. Schematic of the preparation process of Co(II)-PMMA-IICM. • Preferable adsorption performance of Co(II)-PMMA-IICMs were prepared with a novel functional monomer. • The adsorption capacity and imprinting factor in 428.24 mg.g -1 and 2.36 of Co(II)-PMMA-IICM 16 , respectively. • High permeation selectivity factors of Co(II)-PMMA-IICM 16 were 2.11 and 1.55 when Cd(II) and Cu(II) as competitive ion.

Interplay between Brownian motion and cross-linking controls bundling dynamics in actin networks

Morphology changes in cross-linked actin networks are important in cell motility, division, and cargo transport. Here, we study the transition from a weakly cross-linked network of actin filaments to a heavily cross-linked network of actin bundles through microscopic Brownian dynamics simulations. We show that this transition occurs in two stages: first, a composite bundle network of small and highly aligned bundles evolves from cross-linking of individual filaments and, second, small bundles coalesce into the clustered bundle state. We demonstrate that Brownian motion speeds up the first stage of this process at a faster rate than the second. We quantify the time to reach the composite bundle state and show that it strongly increases as the mesh size increases only when the concentration of cross-links is small and that it remains roughly constant if we decrease the relative ratio of cross-linkers as we increase the actin concentration. Finally, we examine the dependence of the bundling timescale on filament length, finding that shorter filaments bundle faster because they diffuse faster.

Closing the loop: Valorizing pyrolyzed waste tyre residue into functional carbon materials, SiO2 with exceptionally high silanol groups, and Zn salt

This study aims to identify suitable processing conditions for converting pyrolytic solid residue from off-the-road tyres (OTR) to improve carbon materials properties that can be used in multiple applications and the recovery of minerals from OTR. Pyrolysis of OTR at 800 °C and a heating rate 2 °C.min−1 gave a carbon material with the highest surface area, most defective carbon structures, and the highest micro-porosity. This operating condition was used to compare the conventional three-step carbonization approach, which involves a demineralization stage that produces high volumes of toxic wastewater, with a two-step approach that bypasses this stage. Analysis of the carbon structures showed that the quality of the carbon material from the two-step approach is similar to the three-step approach. This two-step approach resulted in a solid and a liquid phase, in which ∼ 93.4% of Zn was selectively fractionated to the liquid phase. The wastewater from the acid wash of the carbonized OTR was neutralized to recover the SiO2, of which 55.5% was reactive SiO2. The SiO2 was found to have an exceptionally high cross-linking ratio of 5.94, achievable only when SiO2 is reacted with silane groups. The study demonstrated that the engineered carbon material from OTR has a H2 uptake of 1.03 wt% at 77 K and 1.2 bar, and the sulfonated counterpart was an effective catalyst (64% conversion) for the Aldol condensation of levunilic acid to two dimer products [tetrahydro-2- methyl-5,γ-dioxo-2-furanpentanoic acid (TMDFA) and 3-(2-methyl-5-oxo- tetrahydrofuran-2-yl)-4-oxopentanoic acid (MOTOA)] that are precursors for fuels and chemicals.

Cross-linking of triblock copolymers of functionalized poly(caprolactone) and poly(ethylene glycol): The effect on the formation of viscoelastic thermogels

The objective of this study was to develop methods for reproducible production of partially cross-linked copolymers based on poly(α-benzyl carboxylate-ε-caprolactone) and poly(ethylene glycol) (abbreviated as PBCL-PEG-PBCL) and assess the effect of the type and/or molar ratio of cross-linker to polymer on the formation of viscoelastic thermogels. For this purpose, PBCL-PEG-PBCL block copolymers were prepared through ring-opening polymerization of α-benzyl-ε-caprolactone (BCL) and PEG (1450 kDa) through bulk polymerization. This was followed by the addition of either polycaprolactone triol (PCL-triol), trimethylolpropane (TMP) ethoxylate, or PEG (200 or 400 Da), as potential chemical cross-linkers. Formation of a high molecular weight polymer population for copolymer prepared in the presence of all cross-linkers under study was evidenced through comparison of data from 1H NMR spectroscopy and gel permeation chromatography (GPC). Among different polyols, only the copolymers partially cross-linked with PEG 400 at PEG 400/BCL ratio of 4:10 formed thermo-reversible viscoelastic hydrogels with sol-gel transition temperatures around 23 °C at a concentration of 15% (w/w). The results implied favoured physical association of PEG400 cross-linked or branched PBCL-PEG-PBCL micelles to contribute to the thermo-responsive gelation and viscoelastic behaviour of the product.

Mixed Avanafil and Dapoxetin Hydrochloride cyclodextrin nano-sponges: Preparation, in-vitro characterization, and bioavailability determination

Avanafil (AVA) and Dapoxetine hydrochloride are BCS Class II drugs, which means that the bioavailability depends on its solubility extent.Nano-sponges are hyper-crosslinked cyclodextrin nano-polymers that have been developed recently to make solid particles with nonporous structure; they're prepared by reacting different types of cyclodextrins with an appropriate cross-linking agent like diphenyl carbonate. Nano-sponges can improve the solubility of poorly soluble active molecules and increase stability by protecting labile groups.Hence, the purpose of this work was to study the effects of different types of cyclodextrins and crosslinker ratios on the solubility and oral bioavailability of Avanafil (AVA) and Dapoxetine hydrochloride (DA) by loading them to Nano-sponges prepared by crosslinking of β-CD, SBE-β-CD with diphenyl carbonate (DPC) as a crosslinker at various molar ratios.AVA and DA-loaded nano-sponges were fabricated using the freeze-drying method and characterized for particle size, zeta potential, loading capacities, and in-vitro drug release. Scanning electron microscopy, differential scanning calorimetry, and Fourier transform infrared spectroscopy were used to characterize the NS and AVA/DA incorporation within the NS.In-vitro drug release was significantly higher with AVA and DA-loaded nano-sponges. Furthermore, the results revealed that AVA and DA-loaded nano-sponges fabricated with β-CD had a higher release in dissolution with both drugs than those fabricated using SBE-β-CD.AVA and DA-loaded nano-sponges increased the oral bioavailability of both drugs by 2.5 and 7.5 folds, respectively, when compared to Spedra® and Priligy®. While there is no significant difference in Tmax between F10 and Spedra®, E12 has a faster onset than Priligy®. A one-way ANOVA revealed a substantial increase in Cmax and T1/2 for AVA and DA. Therefore, AVA and DA-loaded nano-sponges are considered a better alternate to the regular dosage forms for efficient AVA and DA oral delivery.

Biocompatible poly(galacturonic acid) micro/nanogels with controllable degradation via tunable chemical crosslinking

Here, one-pot labor-less preparation of two different polygalacturonic acid (PGA) micro/nanogel formulations, PGA-1 and PGA-2, by respectively crosslinking the PGA chains with divinyl sulfone (DVS) and trimethylolpropane triglycidyl ether (TMPGDE) were reported. Various crosslinker ratios, 2.5, 10, 50, and 100% were used for both crosslinkers to demonstrate the tunability of their degradation properties. The PGA micro/nanogels were found spherical-shaped porous particles in 0.5–5.0 μm size range by SEM. The hydrolytic degradation and stability of PGA micro/nanogels in pH 1.0, 7.4, and 9.0 buffer solutions can be controlled by changing the degree of crosslinking. Accordingly, 32 ± 8% and 36 ± 2% weight losses were attained for PGA-1-10% and PGA-2-10% micro/nanogels at pH 1, respectively, and 46 ± 6%, and 68 ± 6% degradations were determined at pH 7.4 within 4 weeks. However, no degradation was observed for both PGA-based micro/nanogel formulations prepared at 25% and 100% crosslinker ratios at all pH conditions. All PGA-based micro/nanogels were totally degraded within 7–10 days at pH 9.0. In the presence of pectinase and amyloglucosidase enzymes, all formulations of PGA micro/nanogels showed more than 80% degradation within 12 h. Furthermore, both PGA formulations showed no significant cytotoxicity against L929 fibroblast cells with 90% and above cell viability up to 250 mg/mL concentrations.

The role of crosslinking density in surface stress and surface energy of soft solids.

Surface stress and surface energy are two fundamental parameters that determine the surface properties of any material. While it is commonly believed that the surface stress and surface energy of liquids are identical, the relationship between the two parameters in soft polymeric gels remains debatable. In this work, we measured the surface stress and surface energy of soft silicone gels with varying weight ratios of crosslinkers in soft wetting experiments. Above a critical density, k0, the surface stress was found to increase significantly with crosslinking density while the surface energy remained unchanged. In this regime, we can estimate a non-zero surface elastic modulus that also increases with the ratio of crosslinkers. By comparing the surface mechanics of the soft gels with their bulk rheology, the surface properties near the critical density k0 were found to be closely related to the underlying percolation transition of the polymer networks.

Platelet-rich fibrin (PRF) gel modified by a carbodiimide crosslinker for tissue regeneration.

Platelet-rich fibrin (PRF) as a rich source of effective growth factors has been used as a scaffold in tissue regeneration. It is known that PRF exhibits rapid degradability against enzymes, which should be decreased using crosslinking agents to reduce the release rate of growth factors and increase the effectiveness of tissue regeneration. In this study, a carbodiimide crosslinker with different concentrations (0.01%, 0.05%, 1%, and 2%) was used to modify and improve the properties of PRF gel. The crosslinked gels were evaluated with analyses such as SEM, swelling, degradability, mechanical strength, release test, cytotoxicity, and cell adhesion. The results showed that with increasing crosslinker concentration, the morphology of the fiber structure changes drastically, the swelling rate decreases from 300% (control) to 160% for the crosslinked gel, the degradation time for the control sample increases from 8 days to more than two weeks for the crosslinked gel, and the Young's modulus increases from 0.15 MPa (control) to 0.61 MPa for the crosslinked samples. Growth factors also showed lower release with increasing crosslinking ratio. Cytotoxicity assays demonstrated that by increasing the crosslinker concentration to 1% w/v, no cytotoxicity was observed. Cellular studies with DAPI staining showed that the cells penetrated well into the gels and were well distributed, especially in gels with lower crosslinker concentrations. In addition, the modified PRF gel can be used as a scaffold for tissue regeneration.

The effect of the cross-linker ratio used in gellan gum biomaterial synthesis on biomineralization

The first step in using polymeric materials for many applications is their crosslinking. Before application, the cross-linker used in crosslinking should be kept at an optimum ratio. The use of gellan gum, a polymeric material, as an intra-body biomaterial is also included in these application areas. In this study, the effect of CaCl2 ratio used as GG cross-linker on the biomineralization of the obtained GG hydrogel was investigated. FTIR, XRD, SEM and EDS analyzes of the synthesized and lyophilized cross-linked GG samples were performed before and after biomineralization. In line with the results obtained, it was observed that the bioactivity of the GG hydrogel could be changed by changing the cross-linking ratio.

PH-Responsive ECM Coating on Ti Implants for Antibiosis in Reinfected Models.

Reinfection of implants during their service life causes troubles to patients. Traditionally, physical loading or chemical bonding of antibacterial agents on implant surfaces cannot settle the repeated bacterial invasion after a period of implantation. In this work, a pH-responsive extracellular matrix (ECM) coating was fabricated on Ti. It consisted of hydroxyapatite (HA) nanorods, antimicrobial peptide (AMP) cross-linked collagen I nanonets (CA nanonets), and physically loaded AMPs. CA nanonets formed in the interspaces of HA nanorods and had an average pore size of 46.5 nm. With the increase in the weight ratio of AMP cross-linkers in collagen I (from 0 to 1:3), the isoelectric points of CA nanonets increased. CA nanonets linked with 50 wt % of AMPs (HCA1) had an isoelectric point of about 7, and their zeta potential shifted from electronegativity to electropositivity when the pH value changed from 7.4 to 6.0. Compared with other nanonets, HCA1 showed a pH-responsive blast release of physically loaded AMPs. It was due to the electrostatic repulsion between the physically adsorbed AMPs and HCA1 after a shift in the potential. In vitro, all the CA nanonets were cytocompatible and exhibited significant short-term antibacterial performance; however, just HCA1 showed outstanding long-time responsive antibacterial activity; in vivo, HCA1 inhibited bacterial infection and suppressed the inflammatory response, especially in a reinfected model, indicating its potential application in Ti implants to mitigate the risk of reinfection.

Water Absorption Enhancement of Sodium Poly Acrylate and Poly(2-Acrylamido-2-Methylpropane Sulphonic Acid) Based Hydrogel Mixtures

Introduction: Hydrogels are hydrophilic polymers which are cross-linked to form three-dimensional structures, which can absorb, swell and retain huge amounts of water or aqueous fluids. Objective: This paper reports the preparation and characterisation of Poly(2-Acrylamido-2-Methylpropane Sulphonic Acid) (PAMPS) hydrogel with different crosslinking intensities. Methodology: 2-Acrylamido-2-methylpropane sulfonic acid (AMPS) monomer was purchased from Alfa Aesar Company as reagent grade. It was used as received (>98% purity) without any further purification. PAMPS hydrogel was prepared by free radical crosslinking solution polymerization of AMPS in water at room temperature under a nitrogen blanket in cylindrical glass tubes. The characteristics of the obtained PAMPS hydrogel were compared with those of commercial sodium polyacrylates hydrogel. Results: It was found that decreasing the crosslinker weight improved the absorbance capacity but to a limit. The suggested reasons were discussed. The mixture showed higher absorbance rate than PAMPS, and bigger absorbance capacity than sodium polyacrylates. Conclusion: This paper investigates the effect of crosslinker ratio on the swelling capacity of PAMPS. It was found that as the crosslinking ratio decreases, the porosity of the hydrogel increases, thus improving the swelling capacity.