Acid Monomers Research Articles

Synergistic expression of ZIF-67 and amphiphilic polymer hydrogel in multi-mode liquid chromatographic separation

In this work, zeolitic imidazolate framework-67 (ZIF-67) with excellent stability synthesized at room temperature was used together with amphiphilic polymer hydrogel to synthesize a captivating mixed-mode silica stationary phase for the first time. The amphiphilic polymer hydrogel prepared by weakly basic cationic and acidic anionic monomers that was modified on the surface of ZIF-67@SiO2 by a simple physical coating method not only improved the separation performance, but also enhanced the applicability of ZIF-67@SiO2 in chromatographic analysis. Meanwhile, the porous ZIF-67 effectively alleviated the problem that polymer hydrogel was easy to swell. To sum up, the amphiphilic polymer hydrogel and ZIF-67 showed excellent synergistic effect in improving the separation ability and the applicability of stationary phase. The experimental results demonstrated that the ZIF-67/hydrogel@SiO2 stationary phase could be applied in various chromatographic separation modes, demonstrating superior resolution and separation selectivity for polycyclic aromatic hydrocarbons, steroid hormones, nucleosides, B-vitamins, sulfonamides, benzoic acids and dinitrobenzene isomers. In this study, the synergistic expression of ZIF-67 and polymer hydrogel provided a new idea for the development of silica stationary phase co-modified by metal-organic framework and hydrogel material. Concurrently, the successful preparation of ZIF-67/hydrogel@SiO2 composite revealed a new possibility for utilizing ZIF-67 as the functional material of stationary phase, expanding the application potential of ZIF-67 in the field of chromatography.

Antiviral Activities of Heparan Sulfate Mimetic RAFT Polymers Against Mosquito-borne Viruses.

Mosquito-borne viruses are a major worldwide health problem associated with high morbidity and mortality rates and significant impacts on national healthcare budgets. The development of antiviral drugs for both the treatment and prophylaxis of these diseases is thus of considerable importance. To address the need for therapeutics with antiviral activity, a library of heparan sulfate mimetic polymers was screened against dengue virus (DENV), Yellow fever virus (YFV), Zika virus (ZIKV), and Ross River virus (RRV). The polymers were prepared by RAFT polymerization of various acidic monomers with a target MW of 20 kDa (average Mn ∼ 27 kDa by GPC). Among the polymers, poly(SS), a homopolymer of sodium styrenesulfonate, was identified as a broad spectrum antiviral with activity against all the tested viruses and particularly potent inhibition of YFV (IC50 = 310 pM). Our results further uncovered that poly(SS) exhibited a robust inhibition of ZIKV infection in both mosquito and human cell lines, which points out the potential functions of poly(SS) in preventing mosquito-borne viruses associated diseases by blocking viral transmission in their mosquito vectors and mitigating viral infection in patients.

Crosslinked PVA-g-poly(AMPS) Nanogels for Enhanced Solubility and Dissolution of Ticagrelor: Synthesis, Characterization, and Toxicity Evaluation.

In this study, we synthesized PVA-g-poly(AMPS) nanogels with the aim of enhancing the solubility and dissolution of ticagrelor (TGR). Ticagrelor, a noncompetitive, reversible P2Y12 receptor antagonist, is prescribed to treat acute coronary syndrome. Ticagrelor has restricted oral bioavailability (≈36%) because of its poor solubility and permeability. The free radical polymerization methodology was employed to synthesize nanogels with varied concentrations of poly(vinyl alcohol) (polymer), 2-acrylamido-2-methylpropanesulfonic acid (monomer), and N,N-methylene bis(acrylamide) (crosslinker). The prepared nanogels were analyzed by swelling studies, % drug entrapment efficiency (DEE), solubility studies, in vitro drug release studies, zeta sizer, Fourier transform infrared (FTIR) spectroscopy, powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM). The optimized formulation (PA5) revealed a particle size of 45.86 nm, with a polydispersity index (PDI) of 0.41 and a %DEE of 85.1%. FTIR spectroscopy, XRD, and SEM confirmed the formation of crosslinked nanogels with amorphous and porous structures, and TGA/DSC proved their thermal stability. In vitro dissolution studies showed 99.91% drug release, and the ticagrelor solubility from the synthesized formulations was significantly improved up to 8.2-fold. All formulations followed the Korsmeyer-Peppas model with the Fickian diffusion as the release mechanism. The toxicity studies carried out on rats and the MTT assay on the Caco-2 cell line validated the biocompatibility of the nanogel formulations. The outcomes of the current study led to the conclusion that the PVA-g-poly(AMPS) nanogels synthesized by us could be used as dedicated pharmaceutical delivery systems to achieve enhanced solubility and dissolution of ticagrelor.

Quantification of microbial community assembly processes during degradation on diverse plastispheres based on physicochemical characters and phylogenetic bin-based null model analysis

To understand the differences in degradation processes depending on the chemical properties of polymers, it is necessary to both quantify the microbiome composition and evaluate the process of microbial turnover (i.e., community assembly processes) in a variety of polymer materials. In this study, using a phylogenetic bin-based null model analysis (i.e., iCAMP), we evaluated community assembly processes from original estuary water to 37 types of polymers, which provide overwhelmingly diverse niches for microbes, in 14-day incubation experiments. First, we evaluated the polymer properties related to degradation rates. Polymers with higher adipic acid (AdA) monomer exhibited higher motility, hydrophilicity, and degradation rates, whereas those with higher aromatic monomer exhibited the opposite trends. Second, microbiome composition analysis was performed, and the microbiomes were significantly changed by the AdA or aromatic content. This was consistent with the polymer properties, suggesting that polymer motility and hydrophilicity attributable to the first-order structure modify the accessibility of the enzyme to the reaction site and hence the degradation rate, resulting in differences in microbiome community composition. Finally, we determined community assembly processes from estuary water to plastics using a phylogenetic bin-based null model analysis. The importance of heterogeneous selection was higher in mobile, hydrophilic, and fast-degrading polymers, while that of homogeneous selection was lower. This suggests that the environmental difference between before and after incubation becomes significant under rapid degradation, which select microbes adapted to biofilm environments. In addition, the more stochastic turnover prevailed, the more variation in the communities (i.e., β-diversity) increased. This suggests that turnover processes not dictated by the environment lead to instability in community compositions.

Preparation of a Porous Protein-Based Composite Material by In Situ Polymerization of Pickering High Internal Phase Emulsion for Adsorption of Lead Ions.

The preparation of complex porous materials using a small molecular surfactant as the stabilizer of a high internal phase emulsion can result in harm to the environment. In this study, porous composites based on soy protein isolate with poly(acrylic acid) were prepared by in situ polymerization of a high internal phase monomer emulsion with an internal phase volume fraction of 80%. The material was prepared from acrylic acid and an N,N-methyl diacrylic acid monomer solution as the continuous phase, peanut oil as the dispersed phase, and soy protein isolate as the composite stabilizer. Scanning electron microscopy showed that porous composites exhibited a concave/convex three-dimensional interpenetrating pore structure. Fourier-transform infrared spectra revealed the existence of many active groups such as carboxyl, amino, hydroxyl, and sulfhydryl. The composite had a high adsorption capacity for lead ions, even at low concentration, with a removal rate of up to 95.7%. The adsorption process conformed to a two-stage model involving internal diffusion and Langmuir isothermal adsorption. The maximum saturated adsorption capacity was 36.71 mg/g when the initial solution concentration was 150 mg/L, the adsorbent concentration was 7.0 g/L, and the adsorption mechanism involved chemical interactions between the lead ions and the composite groups -COOH, -OH, and -SH.

Incorporation of Multiple β2-Hydroxy Acids into a Protein In Vivo Using an Orthogonal Aminoacyl-tRNA Synthetase.

The programmed synthesis of sequence-defined biomaterials whose monomer backbones diverge from those of canonical α-amino acids represents the next frontier in protein and biomaterial evolution. Such next-generation molecules provide otherwise nonexistent opportunities to develop improved biologic therapies, bioremediation tools, and biodegradable plastic-like materials. One monomer family of particular interest for biomaterials includes β-hydroxy acids. Many natural products contain isolated β-hydroxy acid monomers, and polymers of β-hydroxy acids (β-esters) are found in polyhydroxyalkanoate (PHA) polyesters under development as bioplastics and drug encapsulation/delivery systems. Here we report that β2-hydroxy acids possessing both (R) and (S) absolute configuration are substrates for pyrrolysyl-tRNA synthetase (PylRS) enzymes in vitro and that (S)-β2-hydroxy acids are substrates in cellulo. Using the orthogonal MaPylRS/MatRNAPyl synthetase/tRNA pair, in conjunction with wild-type E. coli ribosomes and EF-Tu, we report the cellular synthesis of model proteins containing two (S)-β2-hydroxy acid residues at internal positions. Metadynamics simulations provide a rationale for the observed preference for the (S)-β2-hydroxy acid and provide mechanistic insights that inform future engineering efforts. As far as we know, this finding represents the first example of an orthogonal synthetase that acylates tRNA with a β2-hydroxy acid substrate and the first example of a protein hetero-oligomer containing multiple expanded-backbone monomers produced in cellulo.

AtMYB41 acts as a dual-function transcription factor that regulates the formation of lipids in an organ- and development-dependent manner.

The plant cuticle controls non-stomatal water loss and can serve as a barrier against biotic agents, whereas the heteropolymer suberin and its associated waxes are deposited constitutively at specific cell wall locations. While several transcription factors controlling cuticle formation have been identified, those involved in the transcriptional regulation of suberin biosynthesis remain poorly characterized. The major goal of this study was to further analyse the function of the R2R3-Myeloblastosis (MYB) transcription factor AtMYB41 in formation of the cuticle, suberin, and suberin-associated waxes throughout plant development. For functional analysis, the organ-specific expression pattern of AtMYB41 was analysed and Atmyb41ge alleles were generated using the CRISPR/Cas9 system. These were investigated for root growth and water permeability upon stress. In addition, the fatty acid, wax, cutin, and suberin monomer composition of different organs was evaluated by gas chromatography. The characterization of Atmyb41ge mutants revealed that AtMYB41 negatively regulates the production of cuticular lipids and fatty acid biosynthesis in leaves and seeds, respectively. Remarkably, biochemical analyses indicate that AtMYB41 also positively regulates the formation of cuticular waxes in stems of Arabidopsis thaliana. Overall, these results suggest that the AtMYB41 acts as a negative regulator of cuticle and fatty acid biosynthesis in leaves and seeds, respectively, but also as a positive regulator of wax production in A. thaliana stems.

Magnetic, Biocompatible and Biodegradable Carboxymethyl Cellulose‐Based Hydrogel for Cationic Dye Adsorption

AbstractEnsuring the availability of water resources that are both clean and safe is crucial for the preservation of environmental health and the well‐being of humans. Here, we fabricated carboxymethyl cellulose‐based hydrogel nanocomposite using acrylic acid (AA) and 2‐acrylamido‐2‐methylpropane sulfuric acid (AMPS) monomers and Fe3O4 nanoparticles through a free radical crosslinking process for adsorption of dyes from contaminated water. The synthesized nanocomposite hydrogel was characterized using various techniques, including TEM, XRD, FTIR, SEM‐EDS, TGA, and AFM analysis. The swelling capacity of samples in an aqueous medium at multiple pH levels and the presence of different salts were investigated. The adsorption efficiency of methylene blue (MB) and crystal violet (CV), emphasizing the effect of hydrogel concentration and the medium's pH, was studied. It was concluded that the hydrogel sample containing 17 % AMPS and 51 % AA had better swelling capacity and dye removal efficiency. The dye adsorption kinetics data were fitted to pseudo‐first and second‐order kinetic models and the Langmuir and Temkin isotherm models. The maximum adsorption capacity for MB and CV was 53.97 and 53.57 mg/g, respectively. It was revealed that the pseudo‐second‐order kinetic model could best describe adsorption (qe=79.2 mg/g for MB and qe=65.8 mg/g for CV). The intra‐particle diffusion model was found to be the rate‐limiting mechanism of dye adsorption. Thermodynamic studies proposed that the adsorption of MB and CV was spontaneous and endothermic. Additionally, magnetic nanocomposite hydrogel‘s reusability up to four successive cycles further determines its probability of adsorption of dyes from wastewater.

Antifouling performance enhancement of PES membranes using hydrophilic nanoparticles of poly(dopamine-acrylate) for oil/water separation

Polydopamine-acrylate (P(A-D)x) nanoparticles were blended with polyethersulfone (PES) to fabricate a high-performance hybrid ultrafiltration (UF) membrane for the separation of water from oily wastewater. In tris-alkaline buffer solution at room temperature, P(A-D)x nanoparticles were synthesized by intramolecular Michael addition of dopamine with acrylic acid (AA) monomers. Hybrid PES membranes were prepared using P(A-D)x at 0.05–0.4 wt% and characterized using various assays including Field emission scanning electron microscopy (FESEM), Thermogravimetric analysis (TGA), atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR), and water contact angle (WCA). The membranes showed a significant increase in hydrophilicity, water permeability, and oil rejection (R). The primary and secondary pure water fluxes of the membrane with 0.2 wt% P(A-D)0.25 were 45% and 110.78% higher than those of neat PES membrane, respectively. For 3300 ppm oil feed solution, water flux during water/oil separation increased by 107%, while the oil rejection (R) remained at 99.08%. The surface of membrane was markedly hydrophilic, with a WCA about 40°, much lower than that of the neat PES membrane (80.67°). UF hybrid membranes also showed a remarkable reduction in oil adhesion on the membrane surface as well as superior antifouling performance for membranes containing 0.2 wt% P(A-D)0.25, flux recovery ratio (FRR) = 84.88 ± 3.27%, reversible fouling (Rr) = 51.12 ± 1.09%, and irreversible fouling (Rir) = 15.12 ± 3.27%. In addition, the pure water flux was 446% higher than that of the unmodified membrane after five cycles (900 minutes).

Self-signal electrochemical identification of circulating tumor DNA employing poly-xanthurenic acid assembled on black phosphorus nanosheets

A self-signal electrochemical identification interface was prepared for the determination of circulating tumor DNA (ctDNA) in peripheral blood based on poly-xanthurenic acid (PXTA) assembled on black phosphorus nanosheets (BPNSs) acquired through simple ultrasonication method. The BPNSs with large surface area could be integrated with the xanthurenic acid (XTA) monomers by right of physisorption, and hence improved the electropolymerization efficiency and was beneficial to the enlargement of the signal response of PXTA. The assembled PXTA/BPNSs composite with attractive electrochemical activity was adopted as a platform for the recognition of DNA immobilization and hybridization. The probe ssDNA was covalently fixed onto the PXTA/BPNSs composite with plentiful carboxyl groups through the terminate free amines of DNA probes by use of the 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide and N-hydrosulfosuccinimide cross-linking reaction, accompanied with the decline of the self-signal response. When the hybridization between the probe ssDNA and the target DNA was accomplished, the self-signal response of the composite interface reproduced by virtue of the shaping of helix construction. The determination limit of the assembled DNA identification interface was 2.1 × 10−19 mol/L, and the complementary target DNA concentrations varied from 1.0 × 10−18 mol/L to 1.0 × 10−12 mol/L. The DNA identification platform displayed magnificent sensitivity, specificity and stability, and was efficaciously implemented to the mensuration of ctDNA derived from colorectal cancer.

Evaluating physiochemical characteristics of tragacanth gum-gelatin network hydrogels designed through graft copolymerization technique

The present work deals with the evaluation of the physiochemical and biomedical properties of hydrogels derived from copolymerization of tragacanth gum (TG) and gelatin for use in drug delivery (DD) applications. Copolymers were characterized by field emission-scanning electron micrographs (FE-SEM), electron dispersion X-ray analysis (EDAX), Fourier transform infrared spectroscopy (FTIR), 13C-nuclear magnetic resonance (NMR), thermo-gravimetric analysis (TGA), differential scanning calorimetry (DSC) and X-ray diffraction (XRD) analysis. FE-SEM revealed heterogeneous morphology and XRD analysis demonstrated an amorphous nature with short range pattern of polymer chains within the copolymers. The release of the drug ofloxacin occurred through a non-Fickian diffusion mechanism and the release profile was best described by the Korsmeyer-Peppas kinetic model. The hydrogels exhibited blood compatibility and demonstrated a thrombogenicity value of 75.63 ± 1.98 % during polymer-blood interactions. Polymers revealed mucoadhesive character during polymer-mucous membrane interactions and required 119 ± 8.54 mN detachment forces to detach from the biological membrane. The copolymers illustrated the antioxidant properties as evidenced by 2, 2′-diphenylpicrylhydrazyl (DPPH) assay which demonstrated a 65.71 ± 3.68 % free radical inhibition. Swelling properties analysis demonstrated that by change in monomer and cross linker content during the reaction increased the crosslinking of the network. These results suggest that the pore size of network hydrogels could be controlled as per the requirement of DD systems. The copolymers were prepared at optimized reaction conditions using 14.54 × 10−1 molL−1 of acrylic acid monomer and 25.0 × 10−3 molL−1 of crosslinker NNMBA. The optimized hydrogels exhibited a crosslink density of 2.227 × 10−4 molcm−3 and a mesh size of 7.966 nm. Additionally, the molecular weight between two neighboring crosslinks in the hydrogels was determined to be 5332.209 gmol−1.The results indicated that the combination of protein-polysaccharide has led to the development of hydrogels suitable for potential applications in sustained drug delivery.

Cellulose-reinforced highly stretchable and adhesive eutectogels as efficient sensors

A cellulose-reinforced eutectogel was constructed by deep eutectic solvent (DES) and cotton linter cellulose. Cellulose was dispersed in the ternary DES consisting of acrylic acid, choline chloride and AlCl3·6H2O. The photoinitiator was then introduced into the system to in situ polymerize acrylic acid monomer to form transparent and ionic conductive eutectogels while keeping all the DES. The crosslinks formed by Al3+ induced ionic bonds and reversible links formed by hydrogen bonds give the eutectogels high stretchability (3200 ± 200 % tensile strain), self-adhesive (52.1 kPa to glass), self-healing and good mechanical strength (670 kPa). The eutectogels were assembled into sensors and epidermal patch electrodes that demonstrated high quality human motion sensing and physiological signal detection (electrocardiogram and electromyography). This work provides a facile way to design flexible electronics for sensing.

Antimicrobial Effect of Dental Adhesive on Cariogenic Multi-Species Biofilm

Dental caries, or tooth decay, is one of the most widespread chronic and multifactorial diseases affecting people worldwide. It is described as the localized destruction of tooth structure by acids produced from bacteria fermentation of edible carbohydrates. The disease process begins within the bacterial biofilm on the surfaces of the teeth. Streptococcus sanguinis, Sreptococcusgordonii, and Streptococcus mutans are the main organisms in the biofilm associated with health or disease conditions in the oral cavity. Streptococcus mutans is believed to be the primary cause of enamel demineralization and the development of dental caries. S. gordonii and S. sanguinis belong to a group of streptococci considered health-related commensal oral bacteria, crucial for forming a biofilm on oral hard tissues. Several types of materials with multipurpose characteristics have been incorporated into dental adhesives. Recently, the calcium salt of an acidic monomer (calcium salt of 4-methacryloxyethyl trimellitic acid, or CMET) has been included in dental adhesive and demonstrated to suppress cariogenic biofilm formation of S. mutans. However, using a single-species model may not mimic the intricate antagonistic and synergistic relations that occur in oral biofilms. Therefore, the effect on cariogenic multi-species biofilm was assessed in this study. Dental adhesive consisting of CMET and 10-methacryloyloxydecyl dihydrogen calcium phosphate (MDCP) (Bio-Coat CA) was spread over the flat-bottom surface of the 96-well plate and LED light-cured. Then it was coated with sterile saliva at 37 °C for 45 min to form an acquired pellicle for microbial attachment. The multi-species bacterial suspension containing Streptococcus mutans ATCC 25715, Streptococcus sanguinis ATCC 10556, and Streptococcus gordonii ATCC 10558 was prepared and added to the saliva-coated well. Then, the plate was incubated at 37°C in a 5% CO2 atmosphere for 24 h, 48 h, and 72 h to support the biofilm formation. The number of vital bacteria in the biofilm was determined with the WST-8 Microbial Cell Counting Kit (Dojindo Molecular Technologies, USA). All tests were done in triplicate and repeated three times. For statistical analysis, Kruskal-Wallis and Dunn’s tests were employed. The results showed that at 24 h, 48 h, and 72 h, dental adhesive with CMET could inhibit the biofilm formation of multi-species bacteria significantly compared with controls. The percentages of biofilm inhibition were 29.1%, 34.7%, and 33.2% at 24 h, 48 h, and 72 h, respectively. Dental adhesive containing CMET displayed favorable multi-species biofilm-inhibiting effects up to 72 h of biofilm growth. It is a promising adhesive for use to prevent secondary caries at the sites of restorations.

Soluble Troger’s base-based polybenzimidazoles containing naphthalene units with improved phosphoric acid tolerance for use as high-temperature proton exchange membranes

Most Troger's base (TB)-based polymers reported for high-temperature proton exchange membranes (HT-PEMs) exhibit low phosphoric acid (PA) tolerance due to excessive swelling in PA solution. In this work, a novel dicarboxylic acid monomer containing both naphthalene and TB units (TB-N-COOH) was successfully synthesized, and the corresponding TB-based PBI homopolymer (TB-N-HPBI) was prepared for HT-PEM fuel cells (HT-PEMFCs). In addition, naphthalene units were incorporated into TB-based PBI copolymers (TB-N-CoPBIs). The resulting TB-N-HPBI and TB-N-CoPBIs exhibited high molecular weight and excellent solubility in organic solvents (e.g., DMSO and NMP) because of the twisted TB units. The incorporated naphthalene units significantly improved the oxidative stability. More importantly, the existed naphthalene units in polymer backbones endowed the membranes with excellent PA tolerance capability because of the rigid structure and poor affinity to PA, which limited excessive swelling in 85 wt% PA solution and hence promoted acid uptake capability. Among of them, the TB-N-HPBI membranes showed ultrahigh PA uptake of 508.6%, and resulting in the proton conductivity of 201 mS cm−1 at 160 °C under non-humidity conditions, which are far superior to most reported TB-based polymer membranes. In addition, the maximum peak power density (H2/air) of 437.2 mW cm−2 was achieved. Our present work demonstrated that the incorporation of the naphthalene units into TB-based PBI significantly promoted the improvement of comprehensive performance for HT-PEMFCs.

Comparison of the effects of chlorogenic acid isomers and their compounds on alleviating oxidative stress injury in broilers

The development of large-scale and intensive breeding models has led to increasingly prominent oxidative stress issues in animal husbandry production. Chlorogenic acid (CGA) is an important extract with a variety of biological activities. It is an effective antioxidant drug and shows different antioxidant capacities due to its different chemical structures. Therefore, it is a new research target to determine the proportion of chlorogenic acid isomers with high antioxidant activity to resist the damage caused by oxidative stress. In this experiment, the antioxidant activities of the chlorogenic acid monomer and its compounds were compared by a series of in vitro antioxidant indexes. Based on the above experiments, it was found that LB and LC have superior antioxidant abilities (P < 0.05). Subsequently, 300 healthy 1-day-old Arbor Acres (AA) male broilers with no significant difference in body weight (about 44g) were randomly selected and randomly divided into five groups with 6 replicates in each group and 10 chickens in each replicate. One group was the control group, one group was the model group, and the remaining three groups were the experimental groups. At 37 days of age, animals in the control group were injected with normal saline, and animals in the other four groups were injected with 1 ml/kg 5% hydrogen peroxide (H2O2) through the chest muscle before the supplementation. The control group (control) and the model group (PC) were fed a standard diet. The remaining three groups included the chlorogenic acid (CGA) group, LB group (CIB) and LC group (CIC). In these groups, 50 g/t chlorogenic acid, LB compound or LC compound were added to the basal diet, respectively, and the other feeding conditions remained consistent. The addition of the LB complex to the diet could significantly improve the growth performance and antioxidant performance of broilers (P < 0.05), upregulate the expression of Nuclear factor erythroid 2-related factor 2 (Nrf2) pathway related genes in liver and jejunum (P < 0.05), regulate the disordered intestinal flora, and alleviate the damage caused by oxidative stress. These results suggested for the first time that the LB complex exhibited superior effects in vitro and vivo.

Tailoring Hierarchical Structure and Rare Earth Affinity of Compositionally Identical Polymers via Sequence Control.

Macromolecule sequence, structure, and function are inherently intertwined. While well-established relationships exist in proteins, they are more challenging to define for synthetic polymer nanoparticles due to their molecular weight, sequence, and conformational dispersities. To explore the impact of sequence on nanoparticle structure, we synthesized a set of 16 compositionally identical, sequence-controlled polymers with distinct monomer patterning of dimethyl acrylamide and a bioinspired, structure-driving di(phenylalanine) acrylamide (FF). Sequence control was achieved through multiblock polymerizations, yielding unique ensembles of polymer sequences which were simulated by kinetic Monte Carlo simulations. Systematic analysis of the global (tertiary- and quaternary-like) structure in this amphiphilic copolymer series revealed the effect of multiple sequence descriptors: the number of domains, the hydropathy of terminal domains, and the patchiness (density) of FF within a domain, each of which impacted both chain collapse and the distribution of single- and multichain assemblies. Furthermore, both the conformational freedom of chain segments and local-scale, β-sheet-like interactions were sensitive to the patchiness of FF. To connect sequence, structure, and target function, we evaluated an additional series of nine sequence-controlled copolymers as sequestrants for rare earth elements (REEs) by incorporating a functional acrylic acid monomer into select polymer scaffolds. We identified key sequence variables that influence the binding affinity, capacity, and selectivity of the polymers for REEs. Collectively, these results highlight the potential of and boundaries of sequence control via multiblock polymerizations to drive primary sequence ensembles hierarchical structures, and ultimately the functionality of compositionally identical polymeric materials.

Design and Synthesis of Comb‐Like Bisulfonic Acid Proton Exchange Membrane with Regulated Microstructure

AbstractThe design and synthesis of proton exchange membranes (PEMs) with controllable microstructure and sulfonation degree play a crucial role in enhancing their performance and expanding their application. In this study, the disulfonic acid monomer is designed and prepared to synthesize the comb‐like disulfonic PEMs with controllable ion exchange capacity. The results show that the side chain structure and more concentrated sulfonic acid groups facilitate the aggregation of sulfonic acid groups in the polymer, improve the microphase separation morphology of PEMs, and increase the ionic conductivity. The proton conductivity of the DS‐PXIDI‐60 membrane is approximately 300 mS cm−1. The PEMs with controllable microstructure are prepared by introducing comonomers, including 9,9‐dimethylxanthrene, biphenyl, and p‐terphenyl, with different reactivity, spatial structure, and solubility. Biphenyl is copolymerized to form a copolymer with an alternating structure, and 9, 9‐dimethylxanthrene is copolymerized to form a random copolymer. In addition, it is worth noting that p‐terphenyl is copolymerized to form a microblock structure of the copolymer, with more excellent comprehensive properties. DS‐PXITp‐60 exhibits better performance than Nafion 212 in redox­flow batteries and fuel cells. Therefore, such molecular design and synthesis strategies provide a reference guide for the development of high‐performance PEMs.

Ion-Imprinted Polymer-Based Sensor for the Detection of Mercury Ions.

In this work, the development of a novel method for the detection of mercury (II) ions in wastewater using a mercury ion-imprinted polymer (IIP) combined with a quartz crystal microbalance (QCM) is described. The IIP was successfully synthesized via the polymerization of a of a novel fluorescein- and 2-aminophenol-functionalized methacrylic acid monomer, which was noted to have high binding affinity to mercury (II) ions. This polymer was subsequently coated on a QCM chip to create an IIP-QCM sensor. This sensor was established to have high selectivity and good sensitivity to mercury (II) ions, and had a limit of detection (LOD) of 14.17 ppb, a limit of quantification (LOQ) of 42.94 ppb, a signal-to-noise ratio (S/N) of 4.29, good repeatability, and a working range of 42.94 ppb to 2 ppm. The sensor was also able to analyze tap water and wastewater samples. The IIP-QCM is, therefore, promising as a highly selective, cost-effective, and rapid mercury ion sensor for applications involving the detection of mercury in wastewater.

Poly(Glutamic Acid-Lysine) Hydrogels with Alternating Sequence Resist the Foreign Body Response in Rodents and Non-Human Primates.

The foreign body response (FBR) to implanted biomaterials and biomedical devices can severely impede their functionality and even lead to failure. The discovery of effective anti-FBR materials remains a formidable challenge. Inspire by the enrichment of glutamic acid (E) and lysine (K) residues on human protein surfaces, a class of zwitterionic polypeptide (ZIP) hydrogels with alternating E and K sequences to mitigate the FBR is prepared. When subcutaneously implanted, the ZIP hydrogels caused minimal inflammation after 2 weeks and no obvious collagen capsulation after 6 months in mice. Importantly, these hydrogels effectively resisted the FBR in non-human primate models for at least 2 months. In addition, the enzymatic degradability of the gel can be controlled by adjusting the crosslinking degree or the optical isomerism of amino acid monomers. The long-term FBR resistance and controlled degradability of ZIP hydrogels open up new possibilities for a broad range of biomedical applications.

Agar Graft Modification with Acrylic and Methacrylic Acid for the Preparation of pH-Sensitive Nanogels for 5-Fluorouracil Delivery.

Agar, a naturally occurring polysaccharide, has been modified by grafting it with acrylic (AcA) and methacrylic (McA) acid monomers, resulting in acrylic or methacrylic acid grafted polymer (AA-g-AcA or AA-g-McA) with pH-sensitive swelling behavior. Different ratios between agar, monomers, and initiator were applied. The synthesized grades of both new polymer series were characterized using FTIR spectroscopy, NMR, TGA, DSC, and XRD to ascertain the intended grafting. The percentage of grafting (% G), grafting efficiency (% GE), and % conversion (% C) were calculated, and models with optimal characteristics were further characterized. The swelling behavior of the newly synthesized polymers was studied over time and in solutions with different pH. These polymers were subsequently crosslinked with varying amounts of glutaraldehyde to obtain 5-fluorouracil-loaded nanogels. The optimal ratios of polymer, drug, and crosslinker resulted in nearly 80% loading efficiency. The performed physicochemical characterization (TEM and DLS) showed spherical nanogels with nanometer sizes (105.7-250 nm), negative zeta potentials, and narrow size distributions. According to FTIR analysis, 5-fluorouracil was physically incorporated. The swelling and release behavior of the prepared nanogels was pH-sensitive, favoring the delivery of the chemotherapeutic to tumor cells. The biocompatibility of the proposed nanocarrier was proven using an in vitro hemolysis assay.