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Fourier-transform infrared spectroscopy (FT-IR) spectra of (a) protonated DMAPMA monomer (DMAPMA·HCl), and (b) DMAPMA base monomer.
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The reversible addition-fragmentation chain transfer (RAFT) polymerization of N-[3-(dimethylamino)propyl]methacrylamide hydrochloride (DMAPMA.HCl) was studied. A detailed investigation of the effect of the polymerization conditions was carried out. The polymerization was conducted in a solvent mixture of water (acidic pH) and 2-propanol in the rati...
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... study the structures, FT-IR spectra of DMAPMA base and DMAPMA hydrochloride monomers were shown in Fig. 1. Both spectra indicated the characteristic peaks of the two forms of DMAPMA which were a wide absorption band at 3600-2800 cm −1 , attributed to NH stretching vibrations, and peaks at 1650 and 1530 cm −1 , attributed to CvO stretching vibration and N-H deformation vibration in the amide groups, respectively. A strong band at 1610 cm −1 ...
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... to CvO stretching vibration and N-H deformation vibration in the amide groups, respectively. A strong band at 1610 cm −1 showed the symmetric stretch vibration of the alkene group (CvC) of methacrylamide monomers. Two peaks at 1450 and 1370 cm −1 indicated stretching and bending of alkanes (RCH 2 CH 3 ). However, the DMAPMA·HCl spectrum (Fig. 1a) showed the most distinctive observed bands between 2600 and 2400 cm −1 , attributed to the N-H stretching due to the hydrochloride salt formation which confirmed the DMAPMA was successfully protonated. [44][45][46] Additionally, as shown in Fig. S1 † when compared to the 1 H NMR spectra of DMAPMA·HCl to the unprotonated DMAPMA, the ...
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... cm −1 indicated stretching and bending of alkanes (RCH 2 CH 3 ). However, the DMAPMA·HCl spectrum (Fig. 1a) showed the most distinctive observed bands between 2600 and 2400 cm −1 , attributed to the N-H stretching due to the hydrochloride salt formation which confirmed the DMAPMA was successfully protonated. [44][45][46] Additionally, as shown in Fig. S1 † when compared to the 1 H NMR spectra of DMAPMA·HCl to the unprotonated DMAPMA, the spectrum of the protonated form revealed an increase in the chemical shift, indicating the deshielding of protons affected by the presenting high electronegative chlorine atoms. 47 ...
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Citations
... DNA or RNA). Examples of cationic polymers used for gene delivery include poly(ethylene imine) (PEI), poly(Llysine), poly(β-amino esters), chitosan, polyamidoamine dendrimers and methacrylate-based polymers with cationic side chains [17][18][19][20][21][22][23][24]. Many different polymer properties can be varied in order to achieve superior results in terms of transfection efficiency and cytotoxicity, including but not limited to functional groups, molar mass, polymer architecture (linear or branched) and polymer backbone (degradable or not) [16,23,25,26]. ...
... The bands located in the 3000-2840 cm − 1 region were mainly attributed to the stretching vibrations of C-H bonds from methyl and methylene groups [52]. The overlapping peaks located between 2700 and 2350 cm − 1 may illustrate the weak overlapping bands that designate stretching vibrations of the N -H bonds due to salt formation [53]. and the second band was assigned to the bending vibrations of N-H from secondary amines and the stretching vibrations of C -N bonds, respectively. ...
... Herein, we developed an improved protocol based on clean-up via acetone precipitation to remove interfering substances (absorbent polymers), and hexane to remove adhesive components during subsequent alumina column chromatography. The acetone precipitation method has been used previously to separate polymeric materials such as polymers and proteins (Seymour et al. 1994;Singhsa, Manuspiya, and Narain 2017). A diagram of the Soxhlet, sonication extraction, and clean-up process is shown in Figure 1. ...
An improved method was developed for determining highly toxic 2,3,7,8-substituted polychlorinated dibenzo-p-dioxins and polychlorinated dibenzo-p-furans (PCDD/Fs) in sanitary napkins. Samples were extracted by Soxhlet (50% dichloromethane/hexane) and sonication (hexane), and a multi-layer silica column was used for clean-up after acetone precipitation to separate the superabsorbent polymers. Improved separation efficiency of PCDD/Fs from sanitary napkins with a high level of superabsorbent polymers was achieved using the acetone precipitation method. Hexane was then applied as an alternative solvent to remove residual interfering substances including sticky components contained on sanitary napkins via alumina column chromatography in the second clean-up step. Recoveries approached 100% with an average relative standard deviation of less than 15%, and recoveries of internal standards were from 70.5 to 114.8% and 0.6 to 13.6% for the two extraction methods. The mean method detection limit was 0.075–0.968 pg/g for Soxhlet extraction and 0.0032–0.091 pg/g for sonication extraction. The established method meets the quality criteria for the screening of dioxins stated in EU Regulations 589/2014 and 709/2014, and therefore provides a suitable alternative for the determination of dioxins in sanitary napkins containing superabsorbent polymers.
Understanding the adsorption of polymers onto particles is crucial for many technological and biomedical applications. Even though polymer adsorption on particles is a dynamic process, most experimental techniques can only study the adsorption indirectly, in equilibrium and on the ensemble level. New analysis methods are required to overcome these limitations. We investigated the use of single‐particle electrophoresis to study the adsorption kinetics of cationic polymers onto anionic particles and compared the resulting data to a theoretical model. In this approach, the electrophoretic mobility of single polystyrene (PS) particles, exposed to different concentrations of poly(2‐guanidinoethyl methacrylate), was measured as a function of time. The polymer adsorption leads to an electrophoretic mobility change of the PS particle over time, from the initial negative value to a positive value at equilibrium. By fitting the kinetics data to the Langmuir model, the adsorption rate, desorption rate and equilibrium constant were determined. Finally, the adsorption kinetics of several other polymers was investigated. This showed that the presented technique enables direct analysis and comparison of the kinetics of polymer adsorption on the single‐particle level. This article is protected by copyright. All rights reserved
The poor mechanical strength of the poly(N-[3-(dimethylamino)propyl] methacrylamide) (PDMAPMAAm) hydrogel limits its application as a drug delivery system and antimicrobial agent. In this study, both its morphology and antibacterial effectiveness were controlled through free radical solution polymerization in the presence of cetyltrimethylammonium bromide (CTAB; cationic nonreactive surfactant), forming lyotropic liquid crystal (LLC) mesophases. All the templated reactions proceeded in four different CTAB concentrations with three different concentrations of DMAPMAAm (2.0, 3.0 and 4.0 mol L-1), which were carried out in distilled-deionized water (DDW) using potassium persulfate (KPS) and N,N'-methylenebisacrylamide (BIS) as the initiator and crosslinker, respectively. The pH-dependent phase transition temperature (34 °C at pH 14), compression moduli, antibacterial and diffusion properties, and the effect of the LLC mesophases of CTAB on the hydrogel properties were investigated by mechanical measurements, image analysis, inhibition zone tests, X-ray diffractograms and polarized optical microscopy (POM). It was found that the compression moduli of the templated (T)-PDMAPMAAm hydrogels increased by nearly ten times (from ∼3.0 to 30.0 kPa) compared to that of the isotropic (I) ones. The POM and XRD results before the removal of CTAB exhibited the formation of lamellar and hexagonal mesophases. Further, the inhibition zones showed the ability of the I-PDMAPMAAm hydrogels to reduce the activity of E. coli even in the absence of CTAB, gentamicin (GS) and ciprofloxacin (CF). This was because the quaternary ammonium (QA) groups on the DMAPMAAm units could interact with the bacterial membrane.
In the pursuit of producing functioning synthetic cells from the bottom‐up, DNA nanotechnology has proven to be a powerful tool. However, the crowded yet highly organized arrangement in living cells, bridging from the nano‐ to the micron‐scale, remains challenging to recreate with DNA‐based architectures. Here, laser microprinting is established to print and erase shape‐controlled DNA hydrogels inside the confinement of water‐in‐oil droplets and giant unilamellar lipid vesicles (GUVs). The DNA‐based photoresist consists of a photocleavable inactive DNA linker, which interconnects Y‐shaped DNA motifs when activated by local irradiation with a 405 nm laser. An alternative linker design allows to erase custom features from a preformed DNA hydrogel with feature sizes down to 1.38 μm. The present work demonstrates that the DNA hydrogels can serve as an internal support to stabilize non‐spherical GUV shapes. Overall, DNA‐based photoresists for laser printing in confinement allow to build up architectures on the interior of synthetic cells with light, which diversifies the toolbox of bottom‐up synthetic biology.
Preparation of antibacterial coating materials is considered an effective strategy to prevent medical device-related infections. In the present study, by combining 2-lactobionamidoethyl methacrylamide with a uniquely structured borneol compound, new copolymers poly(2-lactobionamidoethyl methacrylamide-co-glycidyl methacrylate-co-isobornyl acrylate) (poly(LAEMA-co-GMA-co-BA)) were synthesized by a simple free-radical polymerization. An amine containing silane layer was first prepared on the substrate surface by a silanization reaction. The glycopolymers were grafted onto the silane layer through covalent bonding to obtain glycosylated coatings. X-ray photoelectron spectroscopy (XPS) confirmed the successful preparation of the APTES-functionalized surface and polymer layers. The surface wettability was measured by the contact angle (CA). The coated surfaces were relatively flat and smooth as confirmed by Atomic Force Microscopy (AFM). Moreover, the prepared coatings showed good antibacterial adhesion properties toward both E. coli and S. aureus. Furthermore, no significant cytotoxicity to the MRC-5 cells (lung fibroblasts) in vitro was observed, indicating the good biocompatibility of the antibacterial coatings. This study provides an excellent strategy for designing an antibacterial surface containing glycopolymers and natural antibacterial compounds, and these coatings may be suitable for medical devices.
Polypeptide coatings are a cornerstone in the field of surface modification due to their widespread biological potential. As their properties are dictated by their structural features, subsequent control thereof using unique fabrication strategies is important. Herein, we report a facile method of precisely creating densely crosslinked polypeptide films with unusually high random coil content through continuous assembly polymerization via reversible addition–fragmentation chain transfer (CAP‐RAFT). CAP‐RAFT was fundamentally investigated using methacrylated poly‐l‐lysine (PLLMA) and methacrylated poly‐l‐glutamic acid (PLGMA). Careful technique refinement resulted in films up to 36.1±1.1 nm thick which could be increased to 94.9±8.2 nm after using this strategy multiple times. PLLMA and PLGMA films were found to have 30–50 % random coil conformations. Degradation by enzymes present during wound healing reveals potential for applications in drug delivery and tissue engineering.
Polypeptide coatings are a cornerstone in the field of surface modification due to their widespread biological potential. As their properties are dictated by their structural features, subsequent control thereof using unique fabrication strategies is important. Herein, we report a facile method of precisely creating densely crosslinked polypeptide films with unusually high random coil conformations through continuous assembly polymerization via reversible addition–fragmentation chain transfer (CAP-RAFT). CAP-RAFT was fundamentally investigated using methacrylated poly- L -lysine (PLLMA) and methacrylated poly- L -glutamic acid (PLGMA). Careful technique refinement resulted in films up to 36.1 ± 1.1 nm thick which could be increased to 94.9 ± 8.2 nm after using this strategy multiple times. PLLMA and PLGMA films were found to have 30-50% random coil conformations. Degradation by enzymes present during wound healing reveals potential for applications in drug delivery and tissue engineering.
