Diethylamino Ethyl Methacrylate Research Articles

In-situ surface modification of a reverse osmosis membrane with acrylic polymers: Transport and retention of a small neutral organic micropollutant

Highly selective in-situ surface grafting approaches were designed to improve the rejection of 1H-benzotriazole (BTA) by a reverse osmosis (RO) membrane. A commercial FT30 membrane was grafted in-situ for the first time with 2-(diethylamino)ethyl methacrylate (DEAEMA) and 3-(trimethoxysilyl)propyl methacrylate (TMSPMA), respectively, and compared with the state-of-the-art polydopamine (PDA) modification method. The TMSPMA grafting enhanced the BTA rejection from 88.4% to 98.4%, with a minor drop in water permeability (0.3%) compared to the pristine membrane. The FT30-TMSPMA membrane performed considerably better than the FT30-DEAEMA and FT30-PDA membranes. The improved rejection after TMSPMA modification can be ascribed to enhanced steric exclusion and hydrophobic interactions. The boosted hydrophobicity of the FT30-TMSPMA membranes is the result of the hydrophobic nature of the propyl/methyl groups present in TMSPMA, resulting in an 11.3% and 8.8% higher selectivity of BTA compared to the pristine FT30 and FT30-PDA membrane, respectively. The A/B ratio (which indicates the membrane selectivity to water against the solute) of the FT30-TMSPMA membrane increased by 714%, which is the highest enhancement compared to other modified materials reported in the literature until now. This new modification approach is thus highly promising for membrane functionalization to improve the rejection of small neutral organic micropollutants.

The influence of depropagation on PEGMA9 solution radical homopolymerization and copolymerization with DEAEMA: in situ1H-NMR measurements and reactivity ratio estimation by dynamic optimization

The concentration affects the depropagation–propagation equilibrium of PEGMA9 due to the backbone flexibility, but this effect on its copolymerization with DEAEMA is negligible.

Quaternization cross-linking of hyperbranched polyethylene-graft-poly(diethylaminoethyl methacrylate) as antimicrobial separation layer of molecular sieving membrane

Positively charged composite membranes with polyethylene-based antimicrobial separation layers are conveniently developed herein for precise molecular sieving. Quaternization cross-linking between hyperbranched polyethylene-graft-poly(diethylaminoethyl methacrylate) and 1,2-dibromoethane constructs porous networks with abundant quaternary ammonium groups. Modified membranes exhibit different interception capabilities for anions, cations, and neutral molecules. We explain the possible sieving mechanisms with respect to size exclusion, the Donnan effect, and the intrapore energy barrier. A strongly positively charged separation layer introduces the electrostatic interaction which has different effects on cationic, anionic, and neutral molecules during filtration. Membranes prepared by the simple quaternization cross-linking strategy can efficiently separate molecular mixtures with different dimensions or charges. Moreover, the plentiful quaternary ammonium groups endow the membranes with favorable antimicrobial activity against Gram-positive E. coli and Gram-negative S. aureus.

Smart Surfaces with pH-Responsiveness Enhanced by Multiscale Hierarchical Structures Fabricated by Laser Direct Writing.

In contemporary applications, smart surfaces capable of altering their properties in response to external stimuli have garnered significant attention. Nonetheless, the efficient creation of smart surfaces exhibiting robust and rapid responsiveness and meticulous controllability on a large scale remains a challenge. This paper introduces an innovative approach to fabricate smart surfaces with strong pH-responsiveness, combining femtosecond laser direct writing (LDW) processing technology with stimulus-responsive polymer grafting. The proposed model involves the grafting of poly(2-diethylaminoethyl methacrylate) (PDEAEMA) onto rough and patterned Au/polystyrene (PS) bilayer surfaces through Au-SH bonding. The incorporation of LDW processing technology extends the choice of microstructures and roughness achievable on material surfaces, while PDEAEMA imparts pH responsiveness. Our findings revealed that the difference in contact angle between acidic and basic droplets on the rough PDEAEMA-g-Au surface (∼118°) greatly surpasses that on the flat PDEAEMA-g-Au surface (∼72°). Next, by leveraging the precision control over surface microstructures enabled by the LDW processing technique, this difference was further augmented to ∼127° on the optimized patterned PDEAEMA-g-Au surface. Further, we created two distinct combined smart surfaces with varying wettability profiles on which the hydrophilic-hydrophobic boundaries exhibit reliable asymmetric wettability for acidic and basic droplets. Additionally, we prepared a separator, realizing a better visual distinction between acid and base and collecting them separately. Given the effective abilities found in this study, we postulate that our smart surfaces hold substantial potential across diverse applications, encompassing microfluidic devices, intelligent sensors, and biomedicine.

Synthesis and Optimization of Next-Generation Low-Molecular-Weight Pentablock Copolymer Nanoadjuvants.

Polymeric nanomaterials such as Pluronic®-based pentablock copolymers offer important advantages over traditional vaccine adjuvants and have been increasingly investigated in an effort to develop more efficacious vaccines. Previous work with Pluronic® F127-based pentablock copolymers, functionalized with poly(diethyl aminoethyl methacrylate) (PDEAEM) blocks, demonstrated adjuvant capabilities through the antigen presentation and crosslinking of B cell receptors. In this work, we describe the synthesis and optimization of a new family of low-molecular-weight Pluronic®-based pentablock copolymer nanoadjuvants with high biocompatibility and improved adjuvanticity at low doses. We synthesized low-molecular-weight Pluronic® P123-based pentablock copolymers with PDEAEM blocks and investigated the relationship between polymer concentration, micellar size, and zeta potential, and measured the release kinetics of a model antigen, ovalbumin, from these nanomaterials. The Pluronic® P123-based pentablock copolymer nanoadjuvants showed higher biocompatibility than the first-generation Pluronic® F127-based pentablock copolymer nanoadjuvants. We assessed the adjuvant capabilities of the ovalbumin-containing Pluronic® P123-based pentablock copolymer-based nanovaccines in mice, and showed that animals immunized with these nanovaccines elicited high antibody titers, even when used at significantly reduced doses compared to Pluronic® F127-based pentablock copolymers. Collectively, these studies demonstrate the synthesis, self-assembly, biocompatibility, and adjuvant properties of a new family of low-molecular-weight Pluronic® P123-based pentablock copolymer nanomaterials, with the added benefits of more efficient renal clearance, high biocompatibility, and enhanced adjuvanticity at low polymer concentrations.

A niche-mimicking polymer hydrogel-based approach to identify molecular targets for tackling human pancreatic cancer stem cells

BackgroundPancreatic adenocarcinoma (PAAD) is one of the most fatal human cancers, but effective therapies remain to be established. Cancer stem cells (CSCs) are highly resistant to anti-cancer drugs and a deeper understanding of their microenvironmental niche has been considered important to provide understanding and solutions to cancer eradication. However, as the CSC niche is composed of a wide variety of biological and physicochemical factors, the development of multidisciplinary tools that recapitulate their complex features is indispensable. Synthetic polymers have been studied as attractive biomaterials due to their tunable biofunctionalities, while hydrogelation technique further renders upon them a diversity of physical properties, making them an attractive tool for analysis of the CSC niche.MethodsTo develop innovative materials that recapitulate the CSC niche in pancreatic cancers, we performed polymer microarray analysis to identify niche-mimicking scaffolds that preferentially supported the growth of CSCs. The niche-mimicking activity of the identified polymers was further optimized by polyethylene glycol (PEG)-based hydrogelation. To reveal the biological mechanisms behind the activity of the optimized hydrogels towards CSCs, proteins binding onto the hydrogel were analyzed by liquid chromatography with tandem mass spectrometry (LC–MS/MS), and the potential therapeutic targets were validated by looking at gene expression and patients’ outcome in the TCGA database.ResultsPA531, a heteropolymer composed of 2-methoxyethyl methacrylate (MEMA) and 2-(diethylamino)ethyl methacrylate (DEAEMA) (5.5:4.5) that specifically supports the growth and maintenance of CSCs was identified by polymer microarray screening using the human PAAD cell line KLM1. The polymer PA531 was converted into five hydrogels (PA531-HG1 to HG5) and developed to give an optimized scaffold with the highest CSC niche-mimicking activities. From this polymer that recapitulated CSC binding and control, the proteins fetuin-B and angiotensinogen were identified as candidate target molecules with clinical significance due to the correlation between gene expression levels and prognosis in PAAD patients and the proteins associated with the niche-mimicking polymer.ConclusionThis study screened for biofunctional polymers suitable for recapitulation of the pancreatic CSC niche and one hydrogel with high niche-mimicking abilities was successfully fabricated. Two soluble factors with clinical significance were identified as potential candidates for biomarkers and therapeutic targets in pancreatic cancers. Such a biomaterial-based approach could be a new platform in drug discovery and therapy development against CSCs, via targeting of their niche.

SiRNA delivery mediated by pH and redox responsive p(DEAEMA-co-HEMA-g-PEGMA) nanogels

Small interfering RNAs (siRNA) have enabled novel, specific, and efficient treatment of diseases, including cancer. To obtain sufficient and well-controlled intracellular delivery, a drug delivery system is essential. Herein a delivery system for siRNA, composed of cationic biodegradable nanogels, is presented. P(DEAEMA-co-HEMA-g-PEGMA) nanogels with varying ratios of 2-diethyl aminoethyl methacrylate (DEAEMA) and 2-Hydroxyethyl methacrylate (HEMA), crosslinked with tetraethylene glycol dimethacrylate or disulfide-crosslinker bis(2-methacryloyloxy ethyl), are synthesized. The pH-depended nanogel swelling facilitates siRNA loading and endosomal disruption. The disulfide-crosslinker ensures siRNA release by GSH-mediated particle disassociating. The nanogels are within the sub-100nm range in their collapsed state, have a PDI ≥0.4, and a ζ-potential ranging from approximately 5-10 in the swollen state and 22–30 V in the collapsed state and have a swelling ratio up to 1.6 in diameter. Furthermore, the nanogels show good serum-stability, and are capable of delivering siRNA with acceptable cytotoxicity levels. The nanogels induced >90% eGFP-silencing in lung cancer cells, and gene-silencing of the cancer target POLR2A led to siRNA-induced cell death in squamous carcinoma cells. The findings suggest that the nanogel-system may function as a carrier vehicle for cytoplasmic delivery of siRNA.

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.

Molecularly Imprinted Polymer Nanospheres with Hydrophilic Shells for Efficient Molecular Recognition of Heterocyclic Aromatic Amines in Aqueous Solution.

Heterocyclic aromatic amine molecularly imprinted polymer nanospheres with surface-bound dithioester groups (haa-MIP) were firstly synthesized via reversible addition-fragmentation chain transfer (RAFT) precipitation polymerization. Then, a series of core-shell structural heterocyclic aromatic amine molecularly imprinted polymer nanospheres with hydrophilic shells (MIP-HSs) were subsequently prepared by grafting the hydrophilic shells on the surface of haa-MIP via on-particle RAFT polymerization of 2-hydroxyethyl methacrylate (HEMA), itaconic acid (IA), and diethylaminoethyl methacrylate (DEAEMA). The haa-MIP nanospheres showed high affinity and specific recognition toward harmine and its structural analogs in organic solution of acetonitrile, but lost the specific binding ability in aqueous solution. However, after the grafting of the hydrophilic shells on the haa-MIP particles, the surface hydrophilicity and water dispersion stability of the polymer particles of MIP-HSs greatly improved. The binding of harmine by MIP-HSs with hydrophilic shells in aqueous solutions is about two times higher than that of NIP-HSs, showing an efficient molecular recognition of heterocyclic aromatic amines in aqueous solution. The effect of hydrophilic shell structure on the molecular recognition property of MIP-HSs was further compared. MIP-PIA with carboxyl groups containing hydrophilic shells showed the highest selective molecular recognition ability to heterocyclic aromatic amines in aqueous solution.

Demulsification Performance and Mechanism of Tertiary Amine Polymer-Grafted Magnetic Nanoparticles in Surfactant-Free Oil-in-Water Emulsion.

Numerous cationic magnetic nanoparticles (MNPs) have previously been developed for demulsifying oil-in-water (O/W) emulsion, and results showed that the cationic MNPs could effectively flocculate and remove the negatively charged oil droplets via charge attraction; however, to the best of our knowledge, there are no research reports regarding the synergetic influence of both the positive charge density and interfacial activity of MNPs on the demulsification performance. In this study, three tertiary amine polymer-grafted MNPs, namely, poly(2-dimethylaminoethyl acrylate)-grafted MNPs (M-PDMAEA), poly(2-dimethylamino)ethyl methacrylate)-grafted MNPs (M-PDMAEMA), and poly(2-diethylaminoethyl methacrylate)-grafted MNPs (M-PDEAEMA), were synthesized and evaluated for their demulsification performance. Results demonstrated that a high positive charge density and superior interfacial activity of MNPs could cause partial oil droplet re-dispersion when excessive MNPs were introduced, leading to a lower magnetic separation efficiency and narrower demulsification window. Herein, a demulsification window is defined as a range of nanoparticle dosages in which the MNPs can effectively demulsify the O/W emulsion under certain conditions. For highly positively charged MNPs, their good interfacial activity could aggravate the formation of a narrower demulsification window. When tertiary amine polymer-grafted MNPs carried a lower positive charge density or weak interfacial activity, that is, M-PDMAEA at pH 4.0, M-PDMAEMA at pH 5.0-9.0, and M-PDEAEMA at pH 9.0-10.0, wide demulsification windows were observed. Additionally, a recycling experiment suggested that MNPs could maintain high demulsification efficiency up to at least five cycles, indicating their satisfactory recyclability. The three tertiary amine polymer-grafted MNPs can be potentially used for efficient demulsification from surfactant-free O/W emulsion in various pH ranges.

Plasma surface modification of graphene oxide nanosheets for the synthesis of GO/PES nanocomposite ultrafiltration membrane for enhanced oily separation

AbstractIn this study, two different monomers, namely hexafluorobutyl acrylate (HFBA) and diethylaminoethyl methacrylate (DEAEMA) were individually used to modify graphene oxide (GO) nanosheets via environmentally friendly plasma enhanced chemical vapor deposition (PECVD) method. The results from instrumental analyses confirmed the successful deposition of respective functional material onto the nanomaterials. Modified GOs were used as the nano‐fillers to develop composite polyethersulfone (PES) ultrafiltration (UF) membrane with improved surface properties for oily solution treatment. All the developed membranes were characterized with a series of analytical instruments to support the findings of membrane filtration performance. The results indicated that the membrane incorporated with DEAEMA‐GOs (coated with hydrophilic polymer) could achieve better results in terms of oil rejection, antifouling resistance and water recovery rate than the membrane incorporated with HFBA‐GOs (coated with hydrophobic polymer). This is due to the reduced agglomeration between modified GOs as well as better interaction of hydrophilic‐coated GOs with polymer membrane. Compared to the pure water flux of the membrane incorporated with unmodified GO, the membrane incorporated with DEAEMA‐GO achieve approximately 85% higher value with oil removal rate remained almost unchanged (98.94% rejection).

Exploring the Adsorption Performance of Gum Xanthan/Poly (Acrylic Acid-co-2-(Diethlyamino)ethyl Methacrylate) based Adsorbent Toward Cationic and Anionic Dyes

This article describes our experimental study in which a series of semi-interpenetrating polymer networks (semi-IPNs: S-IPN1, S-IPN2, and S-IPN3), based on acrylic acid (AA), 2-(diethylamino)ethyl methacrylate (DEAEMA), and gum xanthan (GX), were used to remove the dyes methylene blue (MB) and Congo red (CR) from synthetic aqueous solutions. The formation of the semi-IPN hydrogel was confirmed by Fourier transform infrared spectroscopy (ATR-FTIR) and scanning electron microscopy (SEM). In the swelling experiments, the hydrogels showed pH-sensitive behavior and swelled the most and least under acidic and alkaline conditions, respectively. The MB and CR uptakes were studied using the batch technique, and the effects of various conditions were investigated. According to the data, 0.1 g of the S-IPN3 hydrogel with the highest content of GX had maximum removal efficiencies of 79.33% and 80.47% for the dyes MB and CR, respectively. Freundlich isotherm and a pseudo-second order kinetic model best explained the equilibrium and kinetic adsorption of the dyes, respectively. The prepared semi-IPN gels also showed high regeneration performance for the cationic dye MB during four consecutive adsorption-desorption cycles.

Controlled biomolecules separation by CO2-responsive block copolymer membranes

The intelligent responsive membranes have aroused much attention due to their distinctive capability to reversibly change separation performances under the stimulation of ambient environment. Especially, the responsive membranes derived from block copolymers, which have regular nanoporous structures, display great potential in high-precision controllable separation. Herein, we use CO2 gas as the non-toxic, mild stimulus, and develop the responsive membranes from a block copolymer of poly(2-diethylaminoethyl methacrylate)-block-polystyrene (PDEAEMA-b-PS) by the selective swelling method. The membranes exhibit a bi-continuous nanoporous structure and the surfaces and pore walls are rich with CO2-responsive PDEAEMA chains. Based on the reversible conformation transition of PDEAEMA chains between the collapsed state and extended state upon CO2/N2 stimulation, the membranes achieve the controllable regulation on the water permeances from ∼100 to ∼2100 L⋅h−1⋅m−2⋅bar−1, also realize the blocking/passing switch for varied proteins. More importantly, the extended PDEAEMA chains shrink the effective pore size down to less than 5 nm, moving the separation scope from ultrafiltration to tight-ultrafiltration. Thus, the membranes are capable to separate macromolecular proteins with small molecule polypeptide and vitamin with high separation efficiencies, demonstrating their application prospect in precise separation and fractionation of biomolecules.

Single-Hole Janus Hollow Sphere.

Cross-linked epoxy resin (EP) single-hole Janus hollow spheres are prepared by cross-linking induced phase separation within an emulsion droplet and selective modification. The droplet is composed of an EP oligomer, toluene, and hexadecane. 2-Ethyl-4-methylimidazole is used as the cross-linker added to the aqueous phase. During the cross-linking, hexadecane forms an eccentric core in the cross-linked EP sphere. A single hole forms across the shell after dissolving the solvents, and a single-hole hollow sphere is achieved. The hole and cavity size are controlled by adjusting the solvent content and cross-linker concentration. Furthermore, frozen wax is used as the core material instead of hexadecane to effectively protect the sphere's interior surface. Selective modification of the exterior and interior surfaces is thus permitted. As an example, a responsive single-hole Janus hollow sphere is prepared by the favorable growth of a silica-polyoxyethylene composite layer onto the exterior surface and a selective grafting of poly(2-diethylaminoethyl methacrylate) (PDEAEMA) by atom-transfer radical polymerization (ATRP) onto the interior. The Janus sphere is water-dispersible and controllably captures and releases oil from the aqueous environment as triggered by the pH value.

Synthesis and characterisation of modified antibacterial styrene-acrylate emulsions for polymer cement waterproof coatings

PurposeThe purpose of this paper is to develop the efficiency of styrene-acrylate (SA) emulsions for polymer cement waterproof coatings with improved bacteria resistance and mechanical properties.Design/methodology/approachFor effective bacteria resistance and excellent mechanical properties, various concentrations of methacryloxyethylhexadecyl dimethylammonium bromide (MHDB) were synthesised and incorporated into SA emulsions. The properties of SA emulsions modified with MHDB were characterised and compared with those of unmodified ones according to the formulations of polymer cement waterproof coatings.FindingsThe SA emulsions modified with MHDB exhibited significant enhancement of bacteria resistance and mechanical properties over the unmodified ones. The positive quaternary nitrogen and long-chain alkyl groups of MHDB in SA emulsions could attract phospholipid head groups of bacterial and insert them into the cell wall, which results in biomass leak and bactericidal effect. Moreover, MHDB as a softened monomer was beneficial to the synthesis of SA copolymer with low glass-transition temperature (Tg), then the copolymer and cement would form a more compact film which was the main reason for the enhancement of mechanical properties.Research limitations/implicationsThe modifier MHDB was synthesised from diethylaminoethyl methacrylate (DEAM) and 1-bromohexadecane. Besides, the congeners of MHDB could be synthesised from DEAM and 1-bromododecane, 1-tetradecyl dromide, 1-octadecyl bromide, etc. In addition, the efficiency of other modifications into SA emulsions for antibacterial polymer cement waterproof coatings could be studied as well.Practical implicationsThe method provided a practical solution for the improvement of water-based antibacterial acrylate polymer cement waterproof coatings.Originality/valueThe method for enhancing bacteria resistance and mechanical properties of the waterproof coating was novel and valuable.

Construction and degradation mechanism of polylactic acid-pH-responsive microgel composite system plugging system

Polylactic acid (PLA) is often used as a degradable temporary plugging agent for bridging plugging, but its particles are rigid, resulting in lax plugging. Based on the acidic properties of the polylactic acid (PLA) degradation solution, pH-responsive microgels were used as flexible filler particles to construct a completely degradable polylactic acid (PLA)-pH-responsive microgel composite temporary plugging system. Using diethylaminoethyl methacrylate (DEAEMA) and acrylamide (AM) as functional monomers, pH-responsive flexible microgel particles were prepared by soap-free emulsion polymerization. The microgels were characterized by FT-IR, SEM, particle size distribution, Zeta potential, electrical conductivity, and surface tension at different pH conditions. The results showed that microgel particles could be completely dissolved in acidic environment. Furthermore, the plugging experiment showed that the plugging rate of the polylactic acid-microgel system reached more than 99%, which was 5.91% higher than that of polylactic acid particles. The addition of pH-responsive microgel could catalyze the degradation of polylactic acid, and the degradation speed was accelerated with the increase of the dosage. Meanwhile, the microgel was completely dissolved by the degradation solution of polylactic acid, forming a clear and transparent solution. Finally, the synergistic degradation mechanism of the polylactic acid-pH-responsive microgel composite system plugging agent system was summarized. This system provides a new idea for the design of a temporary plugging agent and has a broad application prospect in acid fracturing.

Hydrophilic macroporous monoliths with tunable water uptake capacity fabricated by water‐in‐oil high internal phase emulsion templating

AbstractIn this contribution, a series of well‐defined amphiphilic di‐block copolymers poly(ethylene oxide)‐b‐polystyrene (PEO43‐b‐PSx) with different PS segment lengths of x = 41, 78, and 130 units were synthesized through activators regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP). The as‐prepared block copolymers successfully stabilized the water‐in‐oil (W/O) high internal phase emulsions (HIPEs) containing pH responsive monomers 2‐(dimethylamino)ethyl methacrylate (DMAEMA) and 2‐(diethylamino)ethyl methacrylate (DEAEMA). The effect of macro‐surfactant loading, PS segment length, and DMAEMA/DEAEMA content on the stability of HIPEs and the corresponding polyHIPE structure were investigated. Results show that the average void size of polyHIPE decreases with the increase of surfactant concentration. Macroporous morphologies with closed‐cell or open‐cell can be manipulated by surfactant loading as well. The openness of polyHIPE decreases as the increase in hydrophobic PS segment length. Compared to DMAEMA containing HIPE systems, stable DEAEMA containing HIPEs are more easily obtained by using the as‐prepared macro‐surfactant. Stable HIPE with a relatively large amount of DEAEMA, up to 70 vol% of oil‐phase has been achieved. The obtained PDEAEMA‐co‐PS polyHIPEs derived from 0.116 mol% PEO43‐b‐PS41 stabilized emulsion templates show pH responsiveness towards water absorption and the highest acidic water uptake capacity can be up to 6.6 times its weight at equilibrium state. This work paves the way for the preparation of hydrophilic macroporous monolith from stable W/O HIPE template, and confirms the strength of macro‐surfactant in such an approach.

Smart Nanocarrier Based on Poly(oligo(ethylene glycol) methyl ether acrylate) Terminated pH-Responsive Polymer Brushes Grafted Mesoporous Silica Nanoparticles

A platform technology based on inorganic/organic nanoparticles for carrying drugs could be of enormous potential benefit in treating cancer. Surface modification of the nanoparticles with pH-responsive and biocompatible polymers can improve the selectivity and targeting toward the tumor cells. Polyethylene glycol (PEG) and its derivatives being present on the surface could enhance the ability to tailor nanomaterial hydrophilicity and to resist the adhesion of proteins and/or cells. Herein, we report a new nanoplatform based on mesoporous silica nanoparticles (MSNs) conjugated with poly(2-(diethylamino) ethyl methacrylate) (PDEAEMA) brushes as a candidate for stimuli-responsive intracellular drug delivery system. Alkyl bromide functional initiators (end-functionalized PDEAEMA brushes) were derivatized to amine, followed by the reaction with ethylene sulfide and poly(oligo(ethylene glycol) methyl ether acrylate (POEGMEA). Using X-ray photoelectron spectroscopy (XPS) to examine the attachment of POEGMEA, it was found that the POEGMEA molecules in the outer surface of PDEAEMA brushes have been successfully reacted with thiol groups, as indicated by the increase in the peak intensity of the C–O group at 286.5 eV. Brush-modified silica hybrids have an average diameter of ca. 250 nm, as estimated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Rhodamine B dye was loaded into the brush-modified silica hybrids nanoparticles with loading capacity of ca. 74%. The accumulated dye released from brush-modified particles in acidic media was approximately 60%, whereas the dye amount release in basic media was less than 15% after 10 h exposure time. Alamar Blue assay was used to assess the cytotoxicity of MSNs–PDEAEMA, MSNs–PDEAEMA–SH, and MSNs–PDEAEMA–POEGMEA. The results show that all three nanosystems were non-toxic to hMSC with an increase in cell proliferation for MSNs–PDEAEMA–POEGMEA at 50 µg/mL after both 24 and 48 h of incubation.

Structural Exploration of Polycationic Nanoparticles for siRNA Delivery.

RNA interference (RNAi) is a promising approach to the treatment of genetic diseases by the specific knockdown of target genes. Functional polymers are potential vehicles for the effective delivery of vulnerable small interfering RNA (siRNA), which is required for the broad application of RNAi-based therapeutics. The development of methods for the facile modulation of chemical structures of polymeric carriers and an elucidation of detailed delivery mechanisms remain important areas of research. In this paper, we synthesized a series of methacrylate-based polymers with controllable structures and narrow distributions by atom transfer radical polymerization using various combinations of cationic monomers (2-dimethylaminoethyl methacrylate, 2-diethylaminoethyl methacrylate, and 2-dibutylaminoethyl methacrylate) and hydrophobic monomers (2-butyl methacrylate (BMA), cyclohexyl methacrylate, and 2-ethylhexyl methacrylate). These polymers exhibited varying hydrophobicities, charge densities, and pKa values, enabling the discovery of effective carriers for siRNA by in vitro delivery assays. For the polymers with BMA segments, 50% of cationic segments were beneficial to the formation of siRNA nanoparticles (NPs) and the in vitro delivery of siRNA. The optimal ratio varied for different combinations of cationic and hydrophobic segments. In particular, 20k PMB 0.5, PME 0.5, and PEB 1.0 showed >75% luciferase knockdown. Efficacious delivery was dependent on high siRNA binding, the small size of NPs, and balanced hydrophobicity and charge density. Cellular uptake and endosomal escape experiments indicated that carboxybetaine modification of 20k PMB 0.5 did not remarkably affect the internalization of corresponding NPs after incubation for 6 h but significantly reduced the endosomal escape of NPs, which leads to the notable decrease in delivery efficacy of polymers. These results provide insights into the mechanism of polymer-based siRNA delivery and may inspire the development of novel polymeric carriers.

Synthesis, monomer reactivity ratios and antibacterial activity of 2-hydroxy ethyl methacrylate and 2-(Diethylamino) ethyl methacrylate copolymers

Synthesis, monomer reactivity ratios and antibacterial activity of 2-hydroxy ethyl methacrylate and 2-(Diethylamino) ethyl methacrylate copolymers