N-hydroxyethyl Acrylamide Research Articles

Tailoring Hydrogel Sheet Properties through Co-Monomer Selection in AMPS Copolymer Macromers.

This study investigates hydrogels based on 2-Acrylamido-2-methyl-1-propanesulfonic acid sodium salt (AMPS) copolymers, incorporating N-hydroxyethyl acrylamide (HEA) and 3-sulfopropyl acrylate potassium salt (SPA). The addition of HEA and SPA is designed to fine-tune the hydrogels' water absorption and mechanical properties, ultimately enhancing their characteristics and expanding their potential for biomedical applications. A copolymer of AMPS, 2-carboxyethyl acrylate (CEA) combined with methacrylic acid (MAA) as poly(AMPS-stat-CEA-stat-MAA, PACM), was preliminarily synthesized. CEA and MAA were modified with allyl glycidyl ether (AGE) through ring-opening, yielding macromers with pendant allyl groups (PACM-AGE). Copolymers poly(AMPS-stat-HEA-stat-CEA-stat-MAA) (PAHCM) and poly(AMPS-stat-SPA-stat-CEA-stat-MAA) (PASCM) were also synthesized and modified with AGE to produce PAHCM-AGE and PASCM-AGE macromers. These copolymers and macromers were characterized by 1H NMR, FT-IR, and GPC, confirming successful synthesis and functionalization. The macromers were then photocrosslinked into hydrogels and evaluated for swelling, water content, and mechanical properties. The results revealed that the PASCM-AGE hydrogels exhibited superior swelling ratios and water retention, achieving equilibrium water content (~92%) within 30 min. While the mechanical properties of HEA and SPA containing hydrogels show significant differences compared to PACM-AGE hydrogel (tensile strength 2.5 MPa, elongation 47%), HEA containing PAHCM-AGE has a higher tensile strength (5.8 MPa) but lower elongation (19%). In contrast, SPA in the PASCM-AGE hydrogels led to both higher tensile strength (3.7 MPa) and greater elongation (92%), allowing for a broader range of hydrogel properties. An initial study on drug delivery behavior was conducted using PACM-AGE hydrogels loaded with photosensitizers, showing effective absorption, release, and antibacterial activity under light exposure. These AMPS-based macromers with HEA and SPA modifications demonstrate enhanced properties, making them promising for wound management and drug delivery applications.

Molecular docking and molecular dynamics study of 3-hydroxybutyrate with polymers for diabetic ketoacidosis-targeted molecularly imprinted polymers

Context: Molecularly imprinted polymers (MIPs) are promising materials with tailored binding sites that can selectively recognize and bind target molecules. The combined approach of molecular docking and molecular dynamics (MD) simulation provides valuable insights into the interactions between 3-hydroxybutyrate (3HB) and the designed MIPs, shedding light on the intricate details of their binding mechanisms. This information is crucial for designing MIPs with high selectivity and affinity for 3HB, which is a key biomarker of diabetic ketoacidosis (DKA). Aims: To examine the interactions and dynamic behavior of 3HB in a complex with ten polymers by employing molecular docking and MD simulations. Methods: Initially, molecular docking was employed to predict the binding orientations and affinities of the 3HB molecule within the active sites of the polymers. Subsequently, molecular dynamics simulation was utilized to explore the dynamic behavior, stability, and interactions within these complexes for 100 ns. Metabolic and toxicological properties of 3HB using SwissADME were also predicted. Results: N-(hydroxymethyl)acrylamide (NHMAm), hydroxyethyl methacrylate (HEMA), itaconic acid (ITA), and N-[tris(hydroxymethyl)methyl]acrylamide (TrisNHMAm) displayed the strongest interactions with 3HB, with binding affinities of -2.64, 2.523, 2.469, and 2.305 kcal/mol, respectively. Various kinds of molecular interactions influence ligand-polymer binding in a variety of ways, as illustrated by the four polymers with the lowest binding affinities. In molecular dynamics, 4-vinylpyridine (4VP), N,N-dimethylacylamide (DMAm), N-(hydroxyethyl)acrylamide (NHEAm), and hydroxyethyl methacrylate (HEMA) suggest a strong stable complex with 3HB with an overall ΔTOTAL of -0.56, -0.35, -0.32, and -0.27 kcal/mol, respectively. The ADME prediction indicated that 3HB has favorable pharmacokinetic properties. Conclusions: HEMA shows the ability to interact well with 3HB both by molecular docking and molecular dynamics.

Tannic acid based multifunctional hydrogels with mechanical stability for wound healing

Conventional wound dressings have poor tissue adhesion and mechanical stability, restricting their applications in dynamic motion environments. Tannic acid (TA) was ideal candidates for current dressing materials due to their well-known antioxidant and anti-inflammatory properties. However, the inevitable polymerization problem of TA limited the one-step synthesis of dressings. Herein, we reported a simple one-pot method to prepare double-network hydrogels containing N-acryloyl glycinamide (NAGA), N-hydroxyethyl acrylamide (HEAA) and TA. The resulting NHT hydrogel exhibited excellent tensile properties, fatigue resistance, and notch insensitivity to ensure mechanical stability under large deformation and stress in vitro. The NHT hydrogel also demonstrated room-temperature self-healing, broad adhesion to various substrates, synergistic swelling ability. In addition, catechol and benzene rings from TA helped shield against UV radiation and acted as free radical scavengers to relieve oxidative stress in wound damage. As a result, full-layer wounds in mice treated with NHT patches showed a higher healing rate, in which epithelialization was completed within 14 days. The integrated function enables hydrogel to maintain mechanical stability in dynamic motion environments with high strain and defects, with great potential for future clinical translation.

Extreme condition-tolerant stretchable flexible supercapacitor and triboelectric nanogenerator based on carrageenan-enhanced gel for energy storage, energy collection and self-powered sensing

As flexible electronics devices for energy storage, mechanical energy collection and self-powered sensing, stretchable flexible supercapacitor and triboelectric nanogenerator (TENG) have attracted extensive attention. However, it is difficult to satisfy the requirements of high safety and resistance to extreme conditions. Dual roles of mechanical and electrical enhancement of inorganic salt are put forward, and a carrageenan (CG) enhanced poly (N-hydroxyethyl acrylamide)/CG/lithium chloride/glycerol (PCLG) conductive gel is prepared by designing hydrogen bonding self-crosslinking and chain entanglement. A high concentration and rapid deposition strategy is proposed to prepare a PCLG gel-based stretchable flexible all-in-one supercapacitor for energy storage, and a single electrode PCLG gel-based TENG is designed for mechanical energy collection, self-powered strain and tactile sensing. The supercapacitor has high capacitance, excellent cycling stability. The TENG possesses efficient energy harvesting with high and stable output voltage and power density, and sensitive and stable self-powered strain and tactile sensing without external power supply. Even under extreme conditions such as low temperatures, self-healing after damage, prolonged placement, deformation, post-deformation, multiple continuous work, pinprick and burning, the supercapacitor and TENG still have excellent properties. Therefore, we provide novel ideas to design flexible supercapacitor and TENG used under extreme conditions for future wearable electronics.

Evaluation of poly(2-hydroxyethyl methacrylate) and poly(N-hydroxyethyl acrylamide) cryogels as potential quercetin release matrices

Fabrication of a suitable drug delivery system forms an attractive strategy to overcome the low bioavailability of quercetin. Poly(2-hydroxyethyl methacrylate–co-N-hydroxyethyl acrylamide), P(HEMA-co-HEAA) copolymer samples, and homopolymers of 2-hydroxyethyl methacrylate (PHEMA) and N-hydroxyethyl acrylamide (PHEAA) offer potential as quercetin delivery matrices owing to their favorable properties rendered in this study. Free radical polymerization applied under cryogenic conditions produced the polymer gels. The homopolymers and copolymers are noncytotoxic, porous, soft cryogels with surfaces resistant to protein and HCT-116 cancer cell adhesion. In vitro, quercetin release studies from samples reveal swelling-controlled, zero-order drug release at pH = 7.4 and 37 °C with high cumulative release percentages ranging from 92.03% to 94.82%. The durability of the cryogels and limited quercetin release at pH = 2.0 indicate that these cryogels are promising matrices for successfully delivering quercetin to the small intestine, where its primary absorption occurs.

Preparation of xyloglucan-grafted poly(N-hydroxyethyl acrylamide) copolymer by free-radical polymerization for in vitro evaluation of human dermal fibroblasts

Xyloglucan is a rigid polysaccharide that belongs to the carbohydrate family. This hemicellulose compound has been widely used in biomedical research because of its pseudoplastic, mucoadhesive, mucomimetic, and biocompatibility properties. Xyloglucan is a polyose with no amino groups in its structure, which also limits its range of applications. It is still unknown whether grafting hydrophilic monomers onto xyloglucan can produce derivatives that overcome these shortcomings. This work aimed to prepare the first copolymers in which N-hydroxyethyl acrylamide is grafted onto tamarind xyloglucan by free-radical polymerization. The biocompatibility of these structures in vitro was evaluated using human dermal fibroblasts. Gamma radiation-induced graft polymerization was employed as an initiator by varying the radiation dose from 5–25 kGy. The structure of the graft copolymer, Xy-g-poly(N-hydroxyethyl acrylamide), was verified by thermal analysis, Fourier transform infrared spectroscopy, and nuclear magnetic resonance spectroscopy. The findings indicate that the degree of grafting and the cytotoxicity/viability of the xyloglucan-based copolymer were independent of dose. Notably, the grafted galactoxyloglucan exhibited efficient support for human dermal fibroblasts, showing heightened proliferative capacity and superior migration capabilities compared to the unmodified polymer. This copolymer might have the potential to be used in skin tissue engineering.

Development of Multiple Crosslinked Polymers and Its Application in Synthetic-Based Drilling Fluids.

This study addresses the performance challenges of Synthetic-Based Drilling Fluids (SBDF) in deep wells and high-temperature environments by engineering a novel multiple hydrogen-bonded crosslinked polymer, MBAH/nano-SiO2. Synthesized using methyl methacrylate (MMA), butyl methacrylate (BMA), acrylic acid (AA), N-hydroxyethyl acrylamide (HEAA), and nano-silica (nano-SiO2), the polymer improved crosslinking density, thermal properties, particle size distribution, and colloidal stability. The development of a 'weak gel' structure in W/O emulsions improved rheology and electrical stability (ES), with ES values reaching up to 775 V after aging at 180 °C. Moreover, the polymer's amphiphilic structure and the synergistic effect of nano-SiO2 increased emulsion film thickness and strength, further augmenting stability. The high-temperature and high-pressure filtration loss of SBDF was considerably reduced to 7.6 mL, benefiting well wall stability and reservoir damage control. This study provides crucial insights into optimizing multiple hydrogen-bonded crosslinked strategies and polymers in SBDF applications.

RAFT/ROP binary polymerization towards well-defined graft copolymers

The RAFT/ROP binary polymerization enables the efficient synthesis of controlled and well-defined poly(N-hydroxyethyl acrylamide)–poly(ε-caprolactone) (PHEAA-g-PCL) as compared to the conventional “two-step” method.

Synthetic macromolecular peptide-mimetics with amino acid substructure residues as protein stabilising excipients.

The clinical use of protein and peptide biotherapeutics requires fabrication of stable products. This particularly concerns stability towards aggregation of proteins or peptides. Here, we tested a hypothesis that interactions between a synthetic peptide, which is an aggregation-prone region analogue, and its homologous sequence on a protein of interest, could be exploited to design excipients which stabilise the protein against aggregation. A peptide containing the analogue of lysozyme aggregation-prone region (GILQINSRW) was conjugated to a RAFT agent and used to initiate the polymerisation of N-hydroxyethyl acrylamide, generating a GILQINSRW-HEA90 polymer, which profoundly reduced lysozyme aggregation. Substitution of tryptophan in GILQINSRW with glycine, to form GILQINSRG, revealed that tryptophan is a critical amino acid in the protein stabilisation by GILQINSRW-HEA90. Accordingly, polymeric peptide-mimetics of tryptophan, phenylalanine and isoleucine, which are often present in aggregation-prone regions, were synthesized. These were based on synthetic oligomers of acrylamide derivatives of indole-3 acetic acid (IND), phenylacetic acid (PHEN), or 2-methyl butyric acid (MBA), respectively, conjugated with hydrophilic poly(N-hydroxyethyl acrylamide) blocks to form amphiphilic copolymers denoted as INDm-, PHENm- and MTBm-b-HEAn. These materials were tested as protein stabilisers and it was shown that solution properties and the abilities of these materials to stabilise insulin and the peptide IDR 1018 towards aggregation are dependent on the chemical nature of their side groups. These data suggest a structure-activity relationship, whereby the indole-based INDm-b-HEAn peptide-mimetic displays properties of a potential stabilising excipient for protein formulations.

A Shape Memory Hydrogel with Excellent Mechanical Properties, Water Retention Capacity, and Tunable Fluorescence for Dual Encryption.

Information encryption platforms with reliable encryption performance, excellent mechanical performance, and high water retention capacity are highly desired. In this study, a tough double-network hydrogel is designed using the first network of a polyion complex containing lanthanide complexes via one-pot polymerization and the second network of a poly (N-hydroxyethyl acrylamide) (PHEAA) obtained by deep eutectic solvent (DES)-assisted introduction and subsequent photopolymerization. In this system, the pH-induced shape memory function and pH-/wavelength-dependent fluorescence allow the use of the prepared hydrogel as a dual-encryption platform. Owing to its high response reversibility, the hydrogel-based platform exhibits both a high security level and the advantages of rewritability, reprogrammability, and reusability. Additionally, the excellent mechanical properties and water retention capacity owing to the solvent exchange process involving the low-volatility solvent DES and the resulting introduction of the second network of PHEAA offer high practical application value for the hydrogel-based dual encryption platform, demonstrating its potential for information security protection.

Tough Interfacial Adhesion Enabled Extremely Durable Flexible Supercapacitors.

The interfacial void and delamination between the hydrogel electrolyte and flexible electrode caused by the inconformal contact and weak adhesion lead to serious performance degradation of solid-state-sandwiched supercapacitors (SCs) upon repetitive deformation. Herein, we propose a hydrogel polymer electrolyte (HPE) engineering strategy for enhancing the interfacial adhesion (Γ) to achieve extremely durable SCs via the soft, tough, and self-adhesive HPE. Using a self-cross-linked poly(N-hydroxyethyl acrylamide)/H3PO4 (PHEAA/H3PO4) HPE as the model, the interfacial adhesion between HPE and polyaniline (PANI)-modified carbon cloth (CC) electrode (CC/PANI) reaches up to 556 J/m2, leading to excellent durability of electrochemical performance under long-term repetitive deformations. The as-assembled sandwiched SC retains 94.14 and 93.62% of initial capacitance after 180° bending and twisting for 100,000 cycles, respectively. Furthermore, benefiting from the addition of H3PO4, the flexible sandwiched SC displays excellent tolerance to low temperatures and delivers a capacitance retention of 98.03% after 180° bending for 10,000 cycles at -20 °C. This work highlights the importance of interfacial adhesion engineering for the design of extremely deformation-tolerable SCs.

Highly Flexible and Self-Healing Supercapacitor Enabled by Physically Crosslinking Polymer Hydrogel Electrolyte.

Preparation of flexible supercapacitors with excellent mechanical properties and self-healing properties is of great significance but still remains a challenge. A self-healable conductive hydrogel based on poly N-hydroxyethyl acrylamide (PHEAA) is fabricated as electrolyte for supercapacitors. The design of the physically cross-linked dual network, and rich hydrogen bonds endow the hydrogel with robust mechanical properties and strong self-healing ability. The hydrogel exhibited an excellent stretchability (723 %) and a high ionic conductivity (21.8 mS/cm). Specially, by in situ growth of electrode film, a non-laminated supercapacitor is obtained with flexibility and self-healing ability. Due to the non-laminated structure, the supercapacitor can work stably under bending and punching. The supercapacitor possessed an areal capacitance of 253.1 mF/cm2 and the capacitance retention was 80 % after five cutting-healing cycles. The pseudo-capacitance contribution of the supercapacitor after self-healing was discussed. It is noteworthy that the supercapacitor maintains the ability to power a clock after self-healing.

Stereocomplex-Driven Morphological Transition of Coil-Rod-Coil Poly(lactic acid)-Based Cylindrical Nanoparticles.

The stereocomplexation of poly(lactic acid) (PLA) enantiomers opens up an avenue for the formation of new materials with enhanced performance, specifically regarding their mechanical and thermal resistance and resistance to hydrolysis. Despite these useful features, the study of the stereocomplexation between block copolymers based on PLA in solution is limited, and a comprehensive understanding of this phenomenon is urgently needed. Herein, triblock copolymers of poly(N-hydroxyethyl acrylamide) and PL(or D)LA in which PLA was midblock (PHEAAmy-b-PL(D)LAx-b-PHEAAmy) were synthesized and assembled into cylindrical micelles via crystallization-driven self-assembly . The stereocomplexation between enantiomeric micelles facilitates the morphological transition, and the transformation process was investigated in detail by varying the aging temperature, block composition, and solvent. It was found that the solubility of the copolymers played a vital role in determining the occurrence and the speed of the chain exchange between the micelles and the unimers, which thereafter has a significant impact on the shape transition. These results lead to a deeper understanding of the stereocomplex-driven morphological transition process and provide valuable guidance for further optimization of the transition under physiological conditions as a new category of stimuli-responsive systems for biomedical applications.

Preparation and controllable heavy oil viscosity reduction performance of pH-responsive star block copolymers

In this study, a series of S-PHEDM star block copolymers of hydrophilic N-hydroxyethyl acrylamide (HEAm) and pH-responsive N,N-dimethylaminoethyl methacrylate (DMAEMA) were synthesized by reversible addition-fragment chain transfer (RAFT) copolymerization for the controllable viscosity reduction of heavy oil. The structures and average molecular weights of the star polymers were characterized by FT-IR spectra, 1H NMR spectra and GPC measurements. The aggregation behavior and oil/water interfacial properties of S-PHEDM were studied using DLS, TEM and IFT measurements in aqueous solutions with various pH values. The properties of heavy oil emulsions formed by S-PHEDM were monitored under different pH conditions using Turbiscan Lab measurements and optical microscopy at ambient temperature, and cyclic regulation of emulsion stability was successfully achieved through regular adjustments of pH values in oil/water mixing systems. Then, S-PHEDM was applied to the field of heavy oil viscosity reduction. Therein, S-PHEDM-2 achieved a degree of viscosity reduction of 99.88% at a dosage of 1000 mg·L−1 for heavy oil (ηapp, 50 °C = 85820 mPa·s) under alkaline conditions. The dehydration rate of the formed emulsion was 25.58% after standing for 1 h. When the heavy oil mixing system was adjusted to acidic, the heavy oil emulsion demulsified rapidly and achieved a dehydration rate of 90.7% within 1 h. The flexible transformation between viscosity reduction and oil–water separation for the heavy oil/water mixing system by adjusting the pH values provided a new idea to enhance efficiency and reduce costs during heavy oil recovery.

Extreme condition-resistant flexible triboelectric nanogenerator and sensor based on swollen-yet-enhanced and self-healing deep eutectic gel

Triboelectric nanogenerator (TENG) and sensor based on conductive gel have captured more and more attention, while they usually possess poor properties, limiting their wide applications in wearable flexible electronics, especially under extreme conditions (e. g., large force, damage and low temperatures) and long-term use. Herein, inspired by the simultaneous enlargement and enhancement of organisms, we propose a simple method of hydrogen bond self-crosslinking and metal salt-based deep eutectic solvent replacement to synthesize multiple hydrogen bonds-reinforced poly(N-hydroxyethyl acrylamide)/lithium chloride/ethylene glycol (PHEA/LiCl/EG) deep eutectic gel with a swelling yet mechanical and electrical enhancing behaviors, which has high transparency, high toughness and strength, quick self-recovery, good self-healing, environmental stability, low temperatures resistance and low friction. The PHEA/LiCl/EG deep eutectic gel-based TENG possesses excellent energy collection performance to supply power, and has good self-powered sensing performance based on energy harvesting. The PHEA/LiCl/EG deep eutectic gel-based sensor exhibits highly sensitive, long-term stable and fatigue-resistant sensing performances, and can monitor various human movements. Even if they are damaged, or placed for a long time or at low temperatures, the flexible TENG and sensor still have excellent energy harvesting or sensing performance. Therefore, this work presents a novel and simple method to design extreme condition-resistant and environment-stable wearable flexible electronics.

Tough, adhesive biomimetic hyaluronic acid methacryloyl hydrogels for effective wound healing.

The development of cost-effective, biocompatible soft wound dressings is highly desirable; however, conventional dressings are only designed for flat wounds, which creates difficulty with promising healing efficiency in complex practical conditions. Herein, we developed a tough, adhesive biomimetic hyaluronic acid methacryloyl hydrogels composed of chemically crosslinked hyaluronic acid methacryloyl (HAMA) network and poly(N-hydroxyethyl acrylamide) (PHEAA) network rich in multiple hydrogen bonding. Due to the multiple chemical crosslinking sites (acrylamide groups) of HAMA; the bulk HEMA/PHEAA hydrogels presented significant enhancements in mechanical properties (∼0.45MPa) than common hyaluronic acid hydrogels (<0.1MPa). The abundant hydrogen bonding also endowed the resultant hydrogels with extremely high adhesiveness on many nonporous substrates, including glass and biological tissues (e.g., heart, liver, lung, kidney, stomach, and muscle), with a considerable interfacial toughness of ∼1432Jm-2. Accordingly, since both natural hyaluronic acid derivative polymers and hydrophilic PHEAA networks are highly biocompatible, the hydrogel matrix possesses good blood compatibility (<5% of hemolysis ratio) and satisfies the general dressing requirements (>99% of cell viability). Based on these physicochemical features, we have demonstrated that this adhesive hydrogel, administered in the form of a designed patch, could be applied to wound tissue healing by promoting epithelialization, angiogenesis, and collagen deposition. We believe that our proposed biomimetic hydrogel design holds great potential for wound repair and our developed HAMA/PHEAA hydrogels are extremely promising for the next-generation tissue healings in emergency situations.

Preparation of thermosensitive PNIPAm- based copolymers with tertiary amino and hydroxyl monomer for cell attachment and detachment study

Thermo-responsive microcarriers are essential for large-scale expansion of anchorage-dependent cells in a suspension culture. In this study, the authors prepared four different N-isopropylacrylamide (NIPAm)-based thermosensitive copolymers by copolymerizing with N-hydroxyethyl acrylamide (HEAA), 2-Hydroxyethyl methacrylate (HEMA), 2-(Diethylamino) ethylmethacrylate (DEAEMA), and 2-(Dimethylamino) ethylmethacylate (DMAEMA) through free radical polymerization (FRP) and used them for surface modification of Cytodex-3 microcarrier. The thermosensitive characteristic of the copolymers enabled microcarriers to attach and detach cells in response to temperature changes. Herein, NIH 3T3 cells were used as a model cell line and it was found that the cells' adhesion rate on Cytodex-3 microcarriers modified with different formulations of thermosensitive copolymers was greater than unmodified microcarriers. The microcarriers coated with 5 wt% of the copolymer showed better cell attachment than 3 wt% and 10 wt% copolymer coated microcarriers. Particularly, 5 wt% P(NIPAm-5% HEMA) copolymer coated microcarriers showed excellent cell attachment than other formulations. More importantly, as the temperature was reduced to 4 °C, the cells cultured on copolymer modified microcarriers were completely detached as a cell sheet from it withoutproteolytic enzymetreatment. Besides preserving the functionality and integrity of cellular structures, the thermal-induced detachment of cells from modified microcarriers was much higher (∼9.9 x 104 cells/mL) than cells detached from the original Cytodex-3 (∼7.5x103 cells/mL) in 1 h at 4 °C. Therefore, this study verified that microcarriers modified with thermosensitive copolymers exhibited enhanced cell attachment and detachment with temperature change, while maintaining cell functionality, thereby providing adequate number of viable cells for large scale production.

NIPAm-based soft colloidal photonic crystals with high color saturation

Nanogels can form colloidal crystals and exhibit structural color in aqueous solution. However, the strong scattering effect and limited arrangement of the nanogel leads to low color saturation. In this study, a series of monomers N-cyclohexyl maleamic acid (NCMA; refractive index (RI)= 1.523), N-phenyl maleanilic acid (NPMA; RI=1.634) and N-(1-naphthyl) maleamic acid (NNMA; RI=1.706) are copolymerized with N-isopropylacrylamide (NIPAm) to synthesize N-isopropylacrylamide-based (NIPAm-based) monodispersed nanogels. The conjugated molecules NPMA and NNMA in nanogels can greatly improve the color saturation levels of colloidal crystals relative to poly(N-isopropylacrylamide) (PNIPAm) and poly(NIPAm–NCMA) because of the noncovalent interactions and high refractive indices. The color saturation increases with increasing conjugated length and refractive index, and the bandgap can be adjusted by regulating the particle diameter or concentration. By introducing N-hydroxyethyl acrylamide and the crosslinker polyurethane acrylate (PUA) to construct the second polymer network, the embedded colloidal crystals possess reversible thermal responsiveness, and the wavelength of the reflection peak redshifts as drug release increases. These materials show great potential as indicators for drug monitoring and biosensing applications.

Acrylate monomer polymerization triggered by iron oxide magnetic nanoparticles and catechol containing microgels

Phenol and its derivatives are the most used polymerization inhibitors for vinyl-based monomers. Here, we reported a novel catalytic system composed of mussel inspired adhesive moiety, catechol, in combination with iron oxide nanoparticles (IONPs) to generate hydroxyl radical (OH) at pH 7.4. Catechol-containing microgel (DHM) was prepared by copolymerizing dopamine methacrylamide (DMA) and N-hydroxyethyl acrylamide (HEAA), which generated superoxide (O2−) and hydrogen peroxide (H2O2) as a result of catechol oxidation. In the presence of IONPs, the generated reactive oxygen species were further converted to OH, which initiated free radical polymerization of various water-soluble acrylate-based monomers including neutral (acrylamide, methyl acrylamide, etc.), anionic (2-acrylamido-2-methyl-1-propanesulfonic acid sodium salt), cationic ([2-(methacryloyloxy)ethyl]trimethylammonium chloride), and zwitterionic (2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide) monomers. Compared with the typical free radical initiating systems, the reported system does not require the addition of extra initiators for polymerization. During the process of polymerization, a bilayer hydrogel was formed in situ and exhibited the ability to bend during the process of swelling. The incorporation of IONPs significantly enhanced magnetic property of the hydrogel and the combination of DHM and IONPs also improved the mechanical properties of these hydrogels.

Microcontact-Imprinted Optical Sensors for Virulence Factors of Periodontal Disease.

Periodontitis (gum disease) is a common biofilm-mediated oral condition, with around 7% of the adult population suffering from severe disease with risk for tooth loss. Moreover, periodontitis virulence markers have been found in atherosclerotic plaque and brain tissue, suggesting a link to cardiovascular and Alzheimer's diseases. The lack of accurate, fast, and sensitive clinical methods to identify patients at risk leads, on the one hand, to patients being undiagnosed until the onset of severe disease and, on the other hand, to overtreatment of individuals with mild disease, diverting resources from those patients most in need. The periodontitis-associated bacterium, Porphyromonas gingivalis, secrete gingipains which are highly active proteases recognized as key virulence factors during disease progression. This makes them interesting candidates as predictive biomarkers, but currently, there are no methods in clinical use for monitoring them. Quantifying the levels or proteolytic activity of gingipains in the periodontal pocket surrounding the teeth could enable early-stage disease diagnosis. Here, we report on a monitoring approach based on high-affinity microcontact imprinted polymer-based receptors for the Arg and Lys specific gingipains Rgp and Kgp and their combination with surface plasmon resonance (SPR)-based biosensor technology for quantifying gingipain levels in biofluids and patient samples. Therefore, Rgp and Kgp were immobilized on glass coverslips followed by microcontact imprinting of poly-acrylamide based films anchored to gold sensor chips. The monomers selected were N-isopropyl acrylamide (NIPAM), N-hydroxyethyl acrylamide (HEAA) and N-methacryloyl-4-aminobenzamidine hydrochloride (BAM), with N,N'-methylene bis(acrylamide) (BIS) as the crosslinker. This resulted in imprinted surfaces exhibiting selectivity towards their templates high affinity and selectivity for the templated proteins with dissociation constants (K d) of 159 and 299 nM for the Rgp- and Kgp-imprinted, surfaces respectively. The former surface displayed even higher affinity (K d = 71 nM) when tested in dilute cell culture supernatants. Calculated limits of detection for the sensors were 110 and 90 nM corresponding to levels below clinically relevant concentrations.