Synthesis and Characterization of Poly(vinylphosphonic acid-co-acrylic acid) Copolymers for Application in Bone Tissue Scaffolds

Nanozyme-assisted molecularly imprinted polymer-based indirect competitive ELISA for the detection of marine biotoxin

Saxitoxin (STX), which is produced by certain dinoflagellate species, is a type of paralytic shellfish poisoning toxin that poses a serious threat to human health and the environment. Therefore, developing a technology for the convenient and cost-effective detection of STX is imperative. In this study, we developed an affinity peptide-imprinted polymer-based indirect competitive ELISA (ic-ELISA) without using enzyme-toxin conjugates. AuNP/Co3O4@Mg/Al cLDH was synthesized by calcining AuNP/ZIF-67@Mg/Al LDH, which was obtained by combining AuNPs, ZIF-67, and flower-like Mg/Al LDH. This synthesized nanozyme exhibited high catalytic activity (Km = 0.24 mM for TMB and 132.5 mM for H2O2). The affinity peptide-imprinted polymer (MIP) was imprinted with an STX-specific template peptide (STX MIP) on a multi-well microplate and then reacted with an STX-specific signal peptide (STX SP). The interaction between the STX SP and MIP was detected using a streptavidin-coated nanozyme (SA-AuNP/Co3O4@Mg/Al cLDH). The developed MIP-based ic-ELISA exhibited excellent selectivity and sensitivity, with a limit of detection of 3.17 ng/mL (equivalent: 0.317 μg/g). Furthermore, the system was validated using a commercial ELISA kit and mussel tissue samples, and it demonstrated a high STX recovery with a low coefficient of variation. These results imply that the developed ic-ELISA can be used to detect STX in real samples.

The synthesis and adsorption-dispersion properties of PPEGMA-PVPA copolymers in cement paste

This study reports the synthesis of a novel superplasticizer, poly(poly(ethylene glycol)methacrylate)-poly(vinylphosphonic acid) (PPEGMA-PVPA), containing phosphate moieties via solution radical polymerization. By adjusting the feed ratios of monomers, PPEGMA-PVPA copolymers with different phosphate group densities were obtained, and their chemical structure was characterized via FT-IR, 1H NMR spectroscopy and ICP-OES. The results demonstrated that about 70% of the VPA monomer was polymerized. The thermostability of PPEGMA-PVPA was also determined through DSC and TGA. The adsorption-dispersion performance onto cement pastes was investigated using mini-slump test, TOC and zeta potential analysis. It was demonstrated that the adsorption capacity of PPEGMA-PVPA onto cement paste was about 1.4 times stronger than that of the reference polycarboxylate superplasticizer and exhibited excellent adsorption-dispersion performance.

Evaluation of physiochemical and biomedical properties of psyllium-poly(vinyl phosphonic acid-co-acrylamide)-cl-N,N-methylene bis acrylamide based hydrogels

Present investigation deals with the synthesis of psyllium based copolymeric hydrogels and evaluation of their physiochemical and biomedical properties. These copolymers have been prepared by grafting of poly(vinyl phosphonic acid) (poly (VPA)) and poly(acrylamide) (poly(AAm)) onto psyllium in the presence of crosslinker N,N-methylene bis acrylamide (NNMBA). These copolymers [psyllium-poly(VPA-co-AAm)-cl-NNMBA] were characterized by field emission-scanning electron micrographs (FE-SEM), electron dispersion X-ray analysis (EDAX), Atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR), 13C-nuclear magnetic resonance (NMR), X-ray diffraction (XRD), and thermogravimetric analysis (TGA)- differential thermal analysis (DTG). FESEM, AFM and XRD demonstrated heterogeneous morphology with a rough surface and an amorphous nature. Diffusion of ornidazole occurred with a non-Fickian diffusion mechanism, and the release profile data was fitted in the Korsemeyer-Peppas kinetic model. Biochemical analysis of hydrogel properties confirmed the blood-compatible nature during blood-polymer interactions and revealed haemolysis value 3.95 ± 0.05 %. The hydrogels exhibited mucoadhesive character during biomembrane-polymer interactions and demonstrated detachment force = 99.0 ± 0.016 mN. During 2,2-diphenyl-1-picrylhydrazyl reagent (DPPH) assay, free radical scavenging was observed 37.83 ± 3.64 % which illustrated antioxidant properties of hydrogels. Physiological and biomedical properties revealed that these hydrogels could be explored for drug delivery uses.

Design, Synthesis and Actual Applications of the Polymers Containing Acidic P-OH Fragments: Part 2-Sidechain Phosphorus-Containing Polyacids

Macromolecules containing acidic fragments in side-groups—polyacids—occupy a special place among synthetic polymers. Properties and applications of polyacids are directly related to the chemical structure of macromolecules: the nature of the acidic groups, polymer backbone, and spacers between the main chain and acidic groups. The chemical nature of the phosphorus results in the diversity of acidic >P(O)OH fragments in sidechain phosphorus-containing polyacids (PCPAs) that can be derivatives of phosphoric or phosphinic acids. Sidechain PCPAs have many similarities with other polyacids. However, due to the relatively high acidity of −P(O)(OH)2 fragment, bone and mineral affinity, and biocompatibility, sidechain PCPAs have immense potential for diverse applications. Synthetic approaches to sidechain PCPAs also have their own specifics. All these issues are discussed in the present review.

Electrospun Poly(acrylic acid-co-4-styrene sulfonate) as Potential Drug-Eluting Scaffolds for Targeted Chemotherapeutic Delivery Systems on Gastric (AGS) and Breast (MDA-Mb-231) Cancer Cell Lines

Potential drug-eluting scaffolds of electrospun poly(acrylic acid-co-styrene sulfonate) P(AA-co-SS) in clonogenic assays using tumorigenic gastric and ovarian cancer cells were tested in vitro. Electrospun polymer nanofiber (EPnF) meshes of PAA and PSSNa homo- and P(AA-co-SS) copolymer composed of 30:70, 50:50, 70:30 acrylic acid (AA) and sodium 4-styrene sulfonate (SSNa) units were performed by electrospinning (ES). The synthesis, structural and morphological characterization of all EPnF meshes were analyzed by optical and electron microscopy (SEM-EDS), infrared spectroscopy (FTIR), contact angle, and X-ray diffraction (XRD) measurements. This study shows that different ratio of AA and SSNa of monomers in P(AA-co-SS) EPnF play a crucial role in clonogenic in vitro assays. We found that 50:50 P(AA-co-SS) EPnF mesh loaded with antineoplastic drugs can be an excellent suppressor of growth-independent anchored capacities in vitro assays and a good subcutaneous drug delivery system for chemotherapeutic medication in vivo model for surgical resection procedures in cancer research.

New Copolymers of Vinylphosphonic Acid with Hydrophilic Monomers and Their Eu3+ Complexes

Free radical copolymerization is used for the synthesis of novel water-soluble copolymers of vinylphosphonic acid with 2-deoxy-2-methacrylamido-D-glucose or 4-acryloylmorpholine, with varied compositions and molecular masses, as well as for the synthesis of copolymers of vinylphosphonic acid with acrylamide. The obtained copolymers contain 6–97 mol% of vinylphosphonic acid units, and their molecular masses vary from 5•103 to 310•103. The monomer reactivity ratios of vinylphosphonic acid and 2-deoxy-2-methacrylamido-D-glucose in copolymerization are determined for the first time, and their values are 0.04 and 9.02, correspondingly. It is demonstrated that the synthesized copolymers form luminescent mixed-ligand complexes with Eu3+, thenoyltrifluoroacetone, and phenanthroline. The influence of the comonomer’s nature on the intensity of the luminescence of complex solutions is revealed.

Application of poly(vinylphosphonic acid) modified poly(amidoxime) in uptake of uranium from seawater

To enhance the anti-biofouling properties and adsorption capability of poly(amidoxime) (PAO), vinylphosphonic acid (VPA, CH2[double bond, length as m-dash]CH-PO3H2) was polymerized on poly(acrylonitrile) (PAN) surface by plasma technique, followed by amidoximation treatment to convert the cyano group (-C[triple bond, length as m-dash]N) into an amidoxime group (AO, -C(NH2)[double bond, length as m-dash]N-OH). The obtained poly(vinylphosphonic acid)/PAO (PVPA/PAO) was used as an adsorbent in the uptake of U(vi) from seawater. The effect of environmental conditions on the anti-biofouling property and adsorption capability of PVPA/PAO for U(vi) were studied. Results show that the modified PVPA enhances the anti-biofouling properties and adsorption capability of PAO for U(vi). The adsorption process is well described by the pseudo-second-order kinetic model and reached equilibrium in 24 h. Adsorption isotherms of U(vi) on PVPA/PAO can be well fitted by the Langmuir model, and the maximum adsorption capability was calculated to be 145 mg g-1 at pH 8.2 and 298 K. Experimental results highlight the application of PVPA/PAO in the extraction of U(vi) from seawater.

Synthesis and Characterization of Silver-Coated Polymeric Scaffolds for Bone Tissue Engineering: Antibacterial and In Vitro Evaluation of Cytotoxicity and Biocompatibility

In bone tissue engineering, multifunctional composite materials are very challenging. Bone tissue engineering is an innovative technique to develop biocompatible scaffolds with suitable orthopedic applications with enhanced antibacterial and mechanical properties. This research introduces a polymeric nanocomposite scaffold based on arabinoxylan-co-acrylic acid, nano-hydroxyapatite (nHAp), nano-aluminum oxide (nAl2O3), and graphene oxide (GO) by free-radical polymerization for the development of porous scaffolds using the freeze-drying technique. These polymeric nanocomposite scaffolds were coated with silver (Ag) nanoparticles to improve antibacterial activities. Together, nHAp, nAl2O3, and GO enhance the multifunctional properties of materials, which regulate their physicochemical and biomechanical properties. Results revealed that the Ag-coated polymeric nanocomposite scaffolds had excellent antibacterial properties and better microstructural properties. Regulated morphological properties and maximal antibacterial inhibition zones were found in the porous scaffolds with the increasing amount of GO. Moreover, the nanosystem and the polymeric matrix have improved the compressive strength (18.89 MPa) and Young's modulus (198.61 MPa) of scaffolds upon increasing the amount of GO. The biological activities of the scaffolds were investigated against the mouse preosteoblast cell lines (MC3T3-E1) and increasing the quantities of GO helps cell adherence and proliferation. Therefore, our findings showed that these silver-coated polymeric nanocomposite scaffolds have the potential for engineering bone tissue.

Investigation on hydrogen bonds and conformational changes in protein/polysaccharide/ceramic based tri-component system

The main attention of present work is to study the molecular level interactions in the interface of biocomposite to increase their applicability. A specific kind of molecular interaction namely, hydrogen bonds play a vital role in deciding composite property. In this study, we construct a tri-component system based on silk fibroin/sodium alginate/hydroxyapatite by varying protein and polysaccharide proportions using in-situ co-precipitation method. The Fourier Transfer Infrared (FTIR) prediction state that prepared composite exhibit inter-(OH⋯N, OH⋯O, OH⋯π) and intra-(OH⋯OH) molecular hydrogen bonds and their strength are varied in accordance with composition of composite. During composite preparation, conformational changes from the random coil to β-sheet structure through intermediate β-turns exist within the protein molecule that is confirmed by vibrational spectra. The crystallographic profile and morphology of HAP were greatly influenced by virtue of polymer matrix. Simulated body fluid (SBF) immersion study shows that biodegradation and swelling ratio are correlated with type of hydrogen bond and secondary structure of protein. Moreover, the in-vitro biomineralization, cytotoxicity and antibacterial activity of composite were analysed in detail.

Both Phosphonic Acid- and Fluorine-Containing Poly(aryl ether)-hydroxyapatite Biocomposites: Toward Enhanced Biocompatibility and Bonelike Elastic Modulus

Metal-based implants possess excellent mechanical strength, corrosion resistance, and biocompatibility and can deliver favorable performances in clinic treatments. However, modulus mismatching is considered a common defect for metal-based materials, while polymer-based materials with a bonelike elastic modulus have been regarded as one of the most promising candidates for bone replacement implants. In this work, a phosphonic acid- and fluorine-containing poly(aryl ether) (PAE) resin is designed and synthesized, which is determined to be an amorphous polymer with excellent thermostability. The elastic modulus of composites is improved to 15.7 GPa by reinforcing with 60 wt % hydroxyapatite (HA), which demonstrates admirable protein adsorption and hydrophilicity. After 14 days of immersion in simulated body fluid, a layer of HA deposition can be observed, indicating favorable bioactivity in advance, and the preliminary in vitro cell experiments also suggest that PAE-HA composites possess favorable cell responses on adhesion, proliferation, and differentiation, which reveal the feasibility of synthesized polymers to be employed as bone replacement materials, while the adjustability in molecular chains also leaves room for further investigations.

Biomimetic mineralized microenvironment stiffness regulated BMSCs osteogenic differentiation through cytoskeleton mediated mechanical signaling transduction

Construction of biomimetic microenvironment is vital to understand the relationship between matrix mechanical cues and cell fate, as well as to explore potential tissue engineering scaffolds for clinical application. In this study, through the enzymatic mineralizable collagen hydrogel system, we established the biomimetic bone matrix which was capable of realizing mechanical regulation independent of mineralization by incorporation of phosphorylated molecules (vinylphosphonic acid, VAP). Then, based on the biomimetic mineralized matrix with same composition but significantly different mechanical stiffness, we further investigated the effect of matrix stiffness on osteogenic differentiation of bone marrow stromal cells (BMSCs). The results clearly demonstrated that biomimetic mineralized microenvironment with higher mechanical strength promoted osteogenic differentiation of BMSCs. Further mechanism analysis demonstrated that the mineralized hydrogel with higher stiffness promoted cytoskeletal assembly, which enhanced the expression and nuclear colocalization of YAP and RUNX2, thereby promoted the osteogenic differentiation of stem cells. This study supplies a promising material platform not only for bone tissue engineering but also for exploring the mechanism of biomimetic bone matrix mechanics on osteogenesis.

Phosphonic acid-functionalized poly(amido amine) macromers for biomedical applications

Novel phosphonic acid-functionalized poly(amido amine) (PAA) macromers are synthesized through aza-Michael addition of 2-aminoethyl phosphonic acid or its mixture with 5-amino-1-pentanol at different ratios onto N,N'-methylene bis(acrylamide) to control the amount of phosphonic acid functionality. The macromers were homo- and copolymerized with 2-hydroxyethyl methacrylate at different ratios to obtain hydrogels with various hydrophilicities. The hydrogels' swelling, biodegradation and mineralization properties were evaluated. The swelling and degradation rates of the gels can be tuned by the chemical structure of PAA macromer precursors as well as pH and CaCl₂ pre-treatment. The hydrogels show composition-dependent mineralization in SBF and 5xSBF, as evidenced from Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDX) analyses. The degradation products of the hydrogels have no effect on U-2 OS, Saos-2 and NIH 3T3 cells, suggesting their cytocompatibility. Overall, these materials have potential to be used as nontoxic degradable biomaterials.

Osteogenic Differentiation of Human Adipose Tissue-Derived MSCs by Non-Toxic Calcium Poly(ethylene phosphate)s

There is a current clinical need for the development of bone void fillers and bioactive bone graft substitutes. The use of mesenchymal stem cells (MSCs) that are seeded into 3D scaffolds and induce bone generation in the event of MSCs osteogenic differentiation is highly promising. Since calcium ions and phosphates promote the osteogenic differentiation of MSCs, the use of the calcium complexes of phosphate-containing polymers is highly prospective in the development of osteogenic scaffolds. Calcium poly(ethylene phosphate)s (PEP-Ca) appear to be potentially suitable candidates primarily because of PEP's biodegradability. In a series of experiments with human adipose-tissue-derived multipotent mesenchymal stem cells (ADSCs), we demonstrated that PEP-Ca are non-toxic and give rise to osteogenesis gene marker, bone morphogenetic protein 2 (BMP-2) and mineralization of the intercellular matrix. Owing to the synthetic availability of poly(ethylene phosphoric acid) block copolymers, these results hold out the possibility for the development of promising new polymer composites for orthopaedic and maxillofacial surgery.

Biomineralization guided by polydopamine-modifed poly(L-lactide) fibrous membrane for promoted osteoconductive activity

A method to mediate biomineralization of electrospinning poly(L-lactide) (PLLA) fibrous membrane assisted by polydopamine (PDA) coating was developed to obtain enhanced osteoconductive activity. The biomineralization mechanism, surface composition, morphology and hydrophilicity of the original and modified PLLA fibrous membranes were characterized. Results revealed that the PDA coating effectively accelerated the formation of hydroxyapatite (HA) on PLLA fibrous membrane and resulted a great increase in hydrophilicity. Moreover, the tensile property of PLLA fibrous membrane was enhanced by the PDA coating while almost kept unchanged by further immobilized with HA. Cells culture results indicated that the successive introduction of PDA and HA contributed to an obvious improvement in the adhesion and proliferation, as well as up-regulated alkaline phosphatase (ALP) activity and promoted osteogenic-related genes and proteins expression of MC3T3-E1 cells. Overall, the as-prepared PLLA-PDA-HA fibrous membrane can be expected as a favorable scaffold for bone tissue repair.

Study on the Methods of Separation and Detection of Chelates

The separation and purification techniques of chelates can improve the accuracy of detecting results of the chelation rate. As a quantitative indicator of metal ion chelates, the chelation rate can not only reflect the completion of chelation but also determine the amount of metal ions in different forms. The determination of chelation rate can help to determine the suitable chelating reaction conditions, make theoretical basis for the fertilizer efficiency, analyze the stability of chelating fertilizers and study the action mechanism of trace elements. In our study, the methods of separation free metal ions from mixture were reviewed first, including gel filtration chromatography, organic solvent precipitation, ion exchange chromatography, membrane separation and high performance liquid chromatography. Then, the qualitative analysis methods of chelates were introduced briefly, including chemical identification, infrared spectroscopy, ultraviolet spectroscopy. A detailed overview of the quantitative determination methods of chelates were also shown, such as ethylenediaminetetraacetic acid titration, chemical titration, atomic absorption spectrometry, inductively coupled plasma atomic emission spectrometry, inductively coupled plasma mass spectrometry, spectrophotometric, chemical modified electrode. In addition, the merits and demerits of chelated rate determination methods of various determination methods were analyzed, and summarized the applicability of various methods, which provided a theoretical basis for optimizing chelating process, characterizing the structure of chelates and analyzing the mechanism of chelating fertilizer. The current methods of measuring chelation rate were also summarized and prospected.

Enhanced osteogenic activity of phosphorylated polyetheretherketone via surface-initiated grafting polymerization of vinylphosphonic acid

Polyetheretherketone (PEEK) is considered to be a prime candidate with the potential to replace biomedical metallic materials as an orthopedic and dental implant on account of its elastic modulus similar to that of human cortical bone. Unfortunately, its biomedical application is impeded by the bioinert surface property and inferior osteogenic activity. In this work, phosphate groups were incorporated onto the PEEK surface through a single-step UV-initiated graft polymerization of vinylphosphonic acid. Diffuse reflectance Fourier transform infrared spectroscopy (DRFTIR), X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM) revealed that phosphate groups were successfully introduced onto the PEEK surface without apparently altering its surface topographical feature and roughness. Water contact angle measurements diclosed the increasing hydrophilia after surface phosphonation. In vitro cell adhesion, spreading, proliferation, alkaline phosphatase activity, extracellular matrix mineralization, and real-time PCR analyses showed enhanced adhesion, spreading, proliferation and osteogenic differentiation of MC3T3-E1 osteoblast on the surface-phosphorylated PEEK. An in vivo biological evaluation in the rabbit tibiae proximal defect model by means of a histological analysis confirmed that the surface-phosphorylated PEEK had improved bone-implant contact. The obtained results indicate that enhanced osteogenic activity to surface-phosphorylated PEEK, which gives positive information of its potential applications in orthopedic and dental implants.

Studies on the Biocompatibility of Poly(diethyl vinyl-phosphonate) with a New Fluorescent Marker

Utilization of group transfer polymerization for the synthesis of poly(diethyl vinylphosphonate) (PDEVP) allows its controlled end-group functionalization. Thus, a new fluorescent chromophore/PDEVP conjugate is prepared and subjected to biocompatibility tests on two different human cell lines. In contrast to the previous studies, the tagged polymer is not absorbed by cells from the solution and has nearly no impact on cell mortality rate.

The unique calcium chelation property of poly(vinyl phosphonic acid-co-acrylic acid) and effects on osteogenesis in vitro

There is a clear clinical need for a bioactive bone graft substitute. Poly(vinyl phosphonic acid-co-acrylic acid) (PVPA-co-AA) has been identified as a promising candidate for bone regeneration but there is little evidence to show its direct osteogenic effect on progenitor or mature cells. In this study mature osteoblast-like cells (SaOS-2) and human bone marrow-derived mesenchymal stem cells (hBM-MSCs) were cultured with PVPA-co-AA polymers with different VPA:AA ratio and at different concentrations in vitro. We are the first to report the direct osteogenic effect of PVPA-co-AA polymer on bone cells and, more importantly, this effect was dependent on VPA:AA ratio and concentration. Under the optimized conditions, PVPA-co-AA polymer not only has an osteoconductive effect, enhancing SaOS-2 cell mineralization, but also has an osteoinductive effect to promote hBM-MSCs' osteogenic differentiation. Notably, the same PVPA-co-AA polymer at different concentrations could lead to differential osteogenic effects on both SaOS-2 and hBM-MSCs in vitro. This study furthers knowledge of the PVPA-co-AA polymer in osteogenic studies, which is critical when utilizing the PVPA-co-AA polymer for the design of novel bioactive polymeric tissue engineering scaffolds for future clinical applications. © 2017 The Authors Journal of Biomedical Materials Research Part A Published by Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 168-179, 2018.

Poly(vinylphosphonic acid-co-acrylic acid) hydrogels: The effect of copolymer composition on osteoblast adhesion and proliferation

There is a clinical need for a synthetic bone graft substitute that can be used at sites of surgical intervention to promote bone regeneration. Poly(vinylphosphonic acid-co-acrylic acid) (PVPA-co-AA) has recently been identified as a potential candidate for use in bone tissue scaffolds. It is hypothesized that PVPA-co-AA can bind to divalent calcium ions on bone mineral surfaces to control matrix mineralization and promote bone formation. In this study, hydrogels of PVPA-co-AA have been produced and the effect of copolymer composition on the structure and properties of the gels was investigated. It was found that an increase in VPA content led to the production of hydrogels with high porosities and greater swelling capacities. Consequently, improved cell adhesion and proliferation was observed on these hydrogels, as well as superior cell spreading morphologies. Furthermore, whereas poly(acrylic acid) gels were shown to be relatively brittle, an increase in VPA content created more flexible hydrogels that can be more easily molded into bone defect sites. Therefore, this work demonstrates that the mechanical and cell adhesion properties of PVPA-co-AA hydrogels can be tuned for the specific application by altering the copolymer composition. © 2017 The Authors Journal of Biomedical Materials Research Part A Published by Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 255-264, 2018.

Icariin immobilized electrospinning poly(l-lactide) fibrous membranes via polydopamine adhesive coating with enhanced cytocompatibility and osteogenic activity

In this study, icariin (ICA), one of the main active ingredients of Herba Epimedii for osteogenesis, was applied to functionalize electrospinning poly(l-lactide) (PLLA) fibrous membrane via an intermediate layer of polydopamine (PDA) to obtain enhanced cytocompatibility and osteogenic activity. For this purpose, an array of PDA-coated PLLA fibrous membranes (PLLA-0.5PDA, PLLA-1PDA, PLLA-2PDA, PLLA-5PDA) and ICA-modified PLLA-2PDA fibrous membranes (PLLA-2PDA-10ICA, PLLA-2PDA-20ICA, PLLA-2PDA-40ICA) were successively prepared. Successful modification of PDA and ICA onto PLLA fibrous membranes was verified by field emission scanning electron microscope (FESEM), thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS). Besides, the hydrophilicity as well as tensile properties of PLLA fibrous membrane were improved after surface modified with PDA and ICA. In vitro cells culture experiments revealed that the adhesion, proliferation and osteogenic differentiation of MC3T3-E1 cells on the PLLA fibrous membrane were significantly improved by successively immobilized with PDA and ICA. Moreover, the concentration of ICA immobilized on the fibrous membranes has the complicated effects on the MC3T3-E1 cells behavior. The PLLA-2PDA-ICA fibrous membranes with low ICA concentration promoted the cell adhesion and proliferation, but on the contrary, those with high ICA concentration were more beneficial to the enhancement in ALP activity and calcium deposition.

An ionic coordination hybrid hydrogel for bioseparation

An ionic coordination hybrid hydrogel is formed with ionic and covalent crosslinked networks via one-step copolymation.

Occlusion of Sulfate-Based Diblock Copolymer Nanoparticles within Calcite: Effect of Varying the Surface Density of Anionic Stabilizer Chains

Polymerization-induced self-assembly (PISA) offers a highly versatile and efficient route to a wide range of organic nanoparticles. In this article, we demonstrate for the first time that poly(ammonium 2-sulfatoethyl methacrylate)-poly(benzyl methacrylate) [PSEM–PBzMA] diblock copolymer nanoparticles can be prepared with either a high or low PSEM stabilizer surface density using either RAFT dispersion polymerization in a 2:1 v/v ethanol/water mixture or RAFT aqueous emulsion polymerization, respectively. We then use these model nanoparticles to gain new insight into a key topic in materials chemistry: the occlusion of organic additives into inorganic crystals. Substantial differences are observed for the extent of occlusion of these two types of anionic nanoparticles into calcite (CaCO₃), which serves as a suitable model host crystal. A low PSEM stabilizer surface density leads to uniform nanoparticle occlusion within calcite at up to 7.5% w/w (16% v/v), while minimal occlusion occurs when using nanoparticles with a high PSEM stabilizer surface density. This counter-intuitive observation suggests that an optimum anionic surface density is required for efficient occlusion, which provides a hitherto unexpected design rule for the incorporation of nanoparticles within crystals.