Atom Transfer Radical Polymerization Research Articles

Ultrasensitive electrochemical microRNA-21 detection based on MXene and ATRP photocatalytic strategy.

ATi3C2TxMXene-based biosensor has been developedand the photocatalytic atom transfer radical polymerization (photo ATRP) amplification strategy appliedto detect target miRNA-21 (tRNA). Initially, Ti3C2TxMXene nanosheets were synthesized from the Ti3AlC2 MAX precursor via selective aluminum etching. Then, functionalization of Ti3C2TxMXene nanosheets with 3-aminopropyl triethoxysilane (APTES) via silylation reactions to facilitate covalent bonding with hairpin DNA biomolecules specifically designed for tRNA detection. Upon binding with the tRNA, the hairpin DNA liberated the azide (N₃) group, initiating a click reaction to affix to the photo ATRP initiator. Through the ATRP photoreaction, facilitated by an organic photoredox catalyst and light, a significant amount of ferrocenyl methyl methacrylate (FMMA) monomer was immobilized on the electrode. Therefore, the electrochemical signal is amplified. The electrochemical efficacy of the biosensor was assessed using square wave voltammetry (SWV). Under optimized conditions, the biosensor demonstrated remarkable sensitivity in detecting tRNA, with a linear detection range from 0.01 fM to 10pM and a detection limit of 2.81 aM. The findings elucidate that thedeveloped biosensor, in conjunction with the photo ATRP strategy, offers reproducibility, stability, and increasedsensitivity, underscoring its potential applications within the experimental medical sector of the biomolecular industry.

Surface-Grafted Biocompatible Polymer Conductors for Stable and Compliant Electrodes for Brain Interfaces.

Durable and conductive interfaces that enable chronic and high-resolution recording of neural activity are essential for understanding and treating neurodegenerative disorders. These chronic implants require long-term stability and small contact areas. Consequently, they are often coated with a blend of conductive polymers and are crosslinked to enhance durability despite the potentially deleterious effect of crosslinking on the mechanical and electrical properties. Here the grafting of the poly(3,4 ethylenedioxythiophene) scaffold, poly(styrenesulfonate)-b-poly(poly(ethylene glycol) methyl ether methacrylate block copolymer brush to gold, in a controlled and tunable manner, by surface-initiated atom-transfer radical polymerization (SI-ATRP) is described. This "block-brush" provides high volumetric capacitance (120 F cm─3), strong adhesion to the metal (4h ultrasonication), improved surface hydrophilicity, and stability against 10000 charge-discharge voltage sweeps on a multiarray neural electrode. In addition, the block-brush film showed 33% improved stability against current pulsing. This approach can open numerous avenues for exploring specialized polymer brushes for bioelectronics research and application.

Preparation of antifouling reverse osmosis membrane with polyacrylic acid brushes based on polydopamine coating assisted atom transfer radical polymerization

An antifouling polyamide (PA) reverse osmosis (RO) membrane was fabricated in this work by incorporating polyacrylic acid (PAA) brushes onto the membrane surface via polydopamine (PDA)-assisted atom transfer radical polymerization (ATRP). Specifically, a PDA intermediate layer containing the initiator 2-bromoisobutyryl bromide (BIBB) for polymerization was coated on original membrane surface. Then, acrylic acid (AA) was controllably incorporated on the membrane surface in the form of PAA brushes by regulating ATRP reaction time. The PDA-assisted polymerization was mild to the separation layer, and BIBB could be immobilized on the membrane surface with even distribution and controllable density. It was demonstrated that the water contact angle and surface roughness of the RO membranes with PAA brushes was reduced, while the negative charge and hydrophilicity were increased. Simultaneously, the water flux of the membrane was enhanced by 27.8% and the NaCl rejection was maintained compared with that of virgin membrane. Moreover, the modified membrane presented a higher flux recovery ratio and a lower flux decline ratio when lysozyme, bovine serum albumin, humic acid, and sodium alginate were used as model foulants. Besides, the membrane exhibited a satisfactory long-term performance stability. Our work provides a gentle and controllable strategy for the fabrication of antifouling RO membranes with enhanced water permeability and maintained salt rejection, which is crucial for increasing the efficiency of RO processes.

Hydrogen bonds-based flexible regulation of acetaminophen adsorption/desorption behavior in aqueous system: Role of the smart thermoresponsive graphene oxide

Adsorption and regeneration techniques are crucial for the treatment of pharmaceuticals in drinking water. However, adsorbents with strong adsorption binding force and simple regeneration have been a challenging issue in the adsorption area that has not been successfully resolved. In this study, a thermos-responsive smart adsorbent, poly (N-isopropylacrylamide) modified graphene oxide (GO-g-PNIPAM) was successfully synthesized using a “graft from” surface-initiated atom-transfer radical polymerization (Si-ATRP) technology. Acetaminophen (Acet) has an excellent efficient adsorption/desorption behavior (107.40/83.9 mg/g) that is potentially flexible controlled by the modified adsorbent only by adjusting the temperature. This exceptional property is primarily caused by the phenomenon that PNIPAM cooperated with GO to undergo hydrophilic transformation in response to temperature changes, allowing for the free construction and deconstruction of hydrogen bonds between PNIPAM and contaminants. More importantly, as external factors (NaCl and urea) are mediated, the development of hydrogen bonds would be further encouraged to further stabilized the efficiency, and the desorption temperature would continue decrease by 2 and 6 °C, respectively, to promote the regeneration process. This outstanding work provides novel perspectives for subsequent smart sensitive materials to flexibly regulate the treatment efficiency of pollutants.

Organic nanoparticles with tunable size and rigidity by hyperbranching and cross-linking using microemulsion ATRP

Unlike inorganic nanoparticles, organic nanoparticles (oNPs) offer the advantage of "interior tailorability," thereby enabling the controlled variation of physicochemical characteristics and functionalities, for example, by incorporation of diverse functional small molecules. In this study, a unique inimer-based microemulsion approach is presented to realize oNPs with enhanced control of chemical and mechanical properties by deliberate variation of the degree of hyperbranching or cross-linking. The use of anionic cosurfactants led to oNPs with superior uniformity. Benefitting from the high initiator concentration from inimer and preserved chain-end functionality during atom transfer radical polymerization (ATRP), the capability of oNPs as a multifunctional macroinitiator for the subsequent surface-initiated ATRP was demonstrated. This facilitated the synthesis of densely tethered poly(methyl methacrylate) brush oNPs. Detailed analysis revealed that exceptionally high grafting densities (~1 nm-2) were attributable to multilayer surface grafting from oNPs due to the hyperbranched macromolecular architecture. The ability to control functional attributes along with elastic properties renders this "bottom-up" synthetic strategy of macroinitiator-type oNPs a unique platform for realizing functional materials with a broad spectrum of applications.

One‐Pot Catalytic Approaches: Building a New Toolbox for Macromolecular Design

AbstractOne‐pot processes have emerged as a powerful strategy in (macro)molecular synthesis: integrating a multicatalytic process maximizes efficiency, reduces waste, improves profitability, and provides versatile tools for designing of more sustainable processes without compromising selectivity and activity. This review article provides a critical overview of the application of one‐pot transformations in polymerization, with the goal of synthesizing polymers with tailored structures and functions for a wide range of applications. Recent advances in one‐pot polymerization techniques are highlighted, including examples from controlled polymerization methods such as atom transfer radical polymerization, reversible addition‐fragmentation chain transfer polymerization, and ring‐opening polymerization, among others. Special emphasis is placed on the design and optimization of reaction conditions, catalyst systems, and monomer combinations to achieve precise control over polymer structure and functionality.

Sequential assembly enhanced selectivity on magnetic imprinted polymers for specific capture of naringin: A combination of synergistic dual sites and imprinted effect

Green and sustainable recovery of high-value natural flavonoids in agricultural wastes could not only improve natural resource utilization, but also could effectively reduce environmental pollution. Recently, great efforts have been made for research on the development of magnetic imprinted composite adsorbent, but the simultaneous promotion of stable selectivity and high adsorption amounts still faces its challenges. Inspired by “Sandwich-like” transport channels with proper steric and specific affinity sites, herein we designed a new kind of surface-imprinted magnetic colloidal nanocrystal clusters (MCNCs) with dual recognition sites (MCNCs@DR-MIPs) via sequential surface imprinted strategy. A two-step sequential surface-initiated atom transfer radical polymerization (SI-ATRP) was employed to construct the double imprinted sites, which can significantly improve the adsorption selectivity and adsorption amounts. In this design, the metal ion Zn(II) and the low pKa boronic acid APBA (1-allylpyridine-3-boronic acid, pKa = 7.4) could effectively tune the appropriate yolk-shell confinement sites, the obtained artificial double imprinted binding sites establishes the promising chemical environment for selective separation. As expected, the adsorption equilibrium experiments exhibited adsorption kinetics (180 min) and the maximum equilibrium binding capacity (34.60 µmol g−1). In virtue of unique advantages of magnetic separation materials, this novel absorbent exhibited a green and environmentally friendly enrichment process for naringin (NRG). Meanwhile, MCNCs@DR-MIPs showed excellent selectivity (imprinted factor 2.15) and regeneration properties (only decreased by 8.22 % after 7 cycles) for NRG. Additionally, the commercially available NRG could be effectively extracted and concentrated to 94.78 %. This study offers a sustainable effective strategy for flavonoids purification of magnetic separation materials and promotes advance the other natural compounds from agricultural wastes.

Polymeric laser rods based on modified poly(methyl methacrylate) matrix synthesized by FeIII complex catalyzed atom transfer radical polymerization with enhanced optical gain and Photostability

AbstractThe investigation of fabricating ultra‐compact solid‐state dye laser (SSDL) using N'N‐dimethylformamide (DMF) modified poly(methyl methacrylate) (PMMA) as the polymeric matrix was carried out. Atom transfer radical polymerization (ATRP) was introduced to manipulate the polymerization process of PMMA. By adjusting the additive amount of the FeIII complex (mixture of FeCl3 and 2,2’‐Bipyridyl (bPy)), the polymerization degree of PMMA was coordinated to gain better amplified spontaneous emission (ASE) properties of the embedded laser dye, Lumogen Orange 240 (LO). The ASE threshold of the FeIII complex catalyzed sample decreased as high as ~75%, from 225.3 ± 11.2 μJ cm−2 to 57.2 ± 2.9 μJ cm−2, comparing to that measured in common PMMA matrix. Additionally, a secondary dye, Stilbene 420 was added in the system for sharing excess excitation energy and oxidization damage, to overcome the photostability problem caused by the oxygen‐rich solvent, DMF. The operational lifetime of the resulted sample increased 200%, to the similar level of that without DMF component. Finally, by mechanical polishing and coating a thin film of silver at one end of the PMMA rod, an analogous Fabry‐Perot resonator was structured within the rod. Decent laser emission was obtained from the resulted SSDL without complex external cavities.

Forward osmosis membrane substrates with low structure parameter: Modification with PSf‐g‐PMMA graft copolymer

AbstractIn this work, using the combination of atom transfer radical polymerization and click chemistry, the graft copolymer polysulfone‐graft‐poly (methyl methacrylate) (PSf‐g‐PMMA) was synthesized as a modifying agent. The copolymer was embedded in the PSf substrate using a nonsolvent phase inversion method. Then, the modified substrate was used to make thin film composite forward osmosis (TFC‐FO) membranes using the interfacial polymerization method. Also, the effect of PSf‐g‐PMMA copolymer content on the surface properties of the membrane, as well as the filtration performance, was investigated. The increase in hydrophilicity, porosity, and average pore diameter indicated the favorable effect of PSf‐g‐PMMA copolymer on the characteristics of modified substrates. In addition, the improvement in the membrane morphology (an increase in the length and number of finger‐like pores) provided a substrate with low tortuosity and structure parameters. Therefore, the pure water permeability increased from 79.9 LMH/bar for the control membrane to 372.1 LMH/bar for the membrane containing 20 wt.% of PSf‐g‐PMMA copolymer. Investigating the FO separation properties of TFC‐FO membranes showed an increase in water flux and selectivity due to an improvement in the morphology of the modified substrate with low structural parameters. The new TFC‐FO membranes have been optimized, and water flux has significantly improved. Compared with the control membrane, which did not have copolymer blending, the new membranes have a triply enhanced water flux of 17.1 LMH. In addition, the selectivity of these optimized membranes has improved when 1 M NaCl is used as the draw, and DI water is used as the feed in the FO mode.

Durable and dense zwitterionic polymer brushes initiated from surface-segregated cyclic initiator via atom transfer radical polymerization

Immobilization of initiators on a polymer surface for surface-initiated polymerization has primarily been achieved via covalent bonds. However, this approach is subject to limitations, such as the requirement for additional processing steps and different customized methods tailored to the specific characteristics of each polymer. In this study, initiator immobilization was achieved by surface segregation, a phenomenon observed in polymer blends wherein one component spontaneously enriches the surface, thereby enabling the modification of surface properties. Specifically, we designed cyclic oligomers containing an atom transfer radical polymerization (ATRP) initiator. The enhanced performance of surface segregation mediated by the cyclic topology was evaluated, along with the surface-initiated polymerization initiated by the surface-segregated oligomer. The kinetics of the ATRP reaction for the cyclic initiators were investigated, and the zwitterion polymer brush density was also calculated. The robustness of the brushes was evaluated through leaching tests, which revealed no notable alterations before and after the assessments. The antifouling effect of the brushes was confirmed through protein adsorption, platelet adhesion, bacterial attachment, and whole-blood circulation experiments. These antifouling examinations demonstrated reduced substance attachment of zwitterionic polymer brushes. Lastly, experiments on optimizing the ATRP catalyst loading during the surface-initiated ATRP were conducted. The excellent performance of the cyclic initiators is expected to provide new insights and opportunities in the field of surface-initiated polymerization. Moreover, the formation of zwitterion brushes via cyclic initiators holds promise for versatile applications in the field of long-term utilization in biointerfaces, offering a wide range of potential uses.

Tailoring Silk Sericin Grafting: Comparing One‐Step and Two‐Step Approaches for PNIPAM/PAMPS Block Nanoparticles

AbstractStructurally defined, protein‐grafted nanoparticles are widely used in various biomedical applications, particularly as intelligent nanocarriers for drug delivery. The integration of synthetic polymers with natural proteins such as silk sericin enhances the functionality and stability of these nanocarriers, making them suitable for targeted and controlled drug release. In this context, an optimized grafting procedure for silk sericin is presented, employing a protein macroinitiator and atom transfer radical polymerization (ATRP). This study aims to elucidate the significance of the grafting process in tailoring the structure of sericin through the chemistry of synthetic grafts. The grafting procedure uses block copolymers of N‐isopropylacrylamide (NIPAM) and 2‐acrylamido‐2‐methylpropanesulfonic acid (AMPS), such as Poly‐(AMPS‐block‐NIPAM)/Poly‐(NIPAM‐block‐AMPS). The procedure employs both one‐step and two‐step synthesis methods to produce a well‐defined, biofunctionalized sericin. Subsequently, sericin‐based nanoparticles are prepared, demonstrating the significance of the optimized procedure. The synthesized products undergo structural analysis using H‐NMR, FTIR‐ATR, XPS, DLS, and zeta potential measurements. In addition, their thermal behavior is assessed using differential scanning calorimetry. To further investigate the prepared nanoparticles, SEM and DLS analyses are conducted. Through synthesis optimization, position and length of each synthetic block is precisely determined, significantly influencing properties of the grafted products and characteristics of the resulting nanoparticles.

Anthraquinones as organophotoredox catalysts for atom transfer radical polymerization via sequential absorption of visible light

AbstractAnthraquinones have been used as the organophotoredox catalysts to catalyze metal‐free atom transfer radical polymerization (ATRP) under visible light irradiation. Polymers with different molecular weight and molecular weight distribution were obtained under different reaction conditions. The “living”/controlled nature of the polymerization was confirmed by the kinetic study, light on/off experiment and the block copolymer synthesis. The anthraquinones are found to catalyze ATRP via redox mechanism via sequential absorption of visible light. Evidence supported by control experiments showed that the excited anthraquinone radical anion or semiquinone anion generated by photo‐induced single electron reduction or subsequent protonation and further reduction were responsible for the initiation/activation of the polymerization.

Amphiphilic block and random copolymers: aggregation and hydrophobic modification on metal-free tanned collagen fibers

Hydrophobicity enhancement of metal-free leather, which is crucial for improving its comprehensive performance, can be achieved by using amphiphilic copolymer retanning agents. However, the relationship between the sequential structure and the hydrophobic modification effect of amphiphilic copolymers remains unclear. Herein, an amphiphilic block copolymer was synthesized using stearyl methacrylate and 2-(dimethylamino)ethyl methacrylate via atom transfer radical polymerization, and the corresponding random copolymer with similar monomer compositions and molecular weights was prepared for comparison. The aggregation behavior of block and random copolymers was investigated. DLS and TEM results indicate that the block copolymer exhibits a larger aggregate size than the corresponding random copolymer. Molecular dynamics simulations suggest that the block copolymer aggregate exhibit a thicker hydrophilic shell and more concentrated distribution of cationic DMA block than the random copolymer aggregate. Subsequently, the block and random copolymers were used for the hydrophobic modification of metal-free tanned collagen fibers (CFs). The block copolymer shows superior binding capacity to CFs than the random one because of its larger size and more concentrated charge distribution. Hence, the block copolymer can form a dense and uniform hydrophobic film on the surface of collagen fibrils and endow CFs with higher hydrophobicity than the random one. This work provides theoretical guidance for modulating the hydrophobicity of CFs by tailoring the sequential structure of amphiphilic copolymers, which is expected to inspire the manufacturing of high-performance metal-free leather.Graphical

Open-Air Chemical Recycling: Fully Oxygen-Tolerant ATRP Depolymerization.

While oxygen-tolerant strategies have been overwhelmingly developed for controlled radical polymerizations, the low radical concentrations typically required for high monomer recovery render oxygen-tolerant solution depolymerizations particularly challenging. Here, an open-air atom transfer radical polymerization (ATRP) depolymerization is presented, whereby a small amount of a volatile cosolvent is introduced as a means to thoroughly remove oxygen. Ultrafast depolymerization (i.e., 2 min) could efficiently proceed in an open vessel, allowing a very high monomer retrieval to be achieved (i.e., ∼91% depolymerization efficiency), on par with that of the fully deoxygenated analogue. Oxygen probe studies combined with detailed depolymerization kinetics revealed the importance of the low-boiling point cosolvent in removing oxygen prior to the reaction, thus facilitating effective open-air depolymerization. The versatility of the methodology was demonstrated by performing reactions with a range of different ligands and at high polymer loadings (1 M monomer repeat unit concentration) without significantly compromising the yield. This approach provides a fully oxygen-tolerant, facile, and efficient route to chemically recycle ATRP-synthesized polymers, enabling exciting new applications.

XPS Depth-Profiling Studies of Chlorophyll Binding to Poly(cysteine methacrylate) Scaffolds in Pigment-Polymer Antenna Complexes Using a Gas Cluster Ion Source.

X-ray photoelectron spectroscopy (XPS) depth-profiling with an argon gas cluster ion source (GCIS) was used to characterize the spatial distribution of chlorophyll a (Chl) within a poly(cysteine methacrylate) (PCysMA) brush grown by surface-initiated atom-transfer radical polymerization (ATRP) from a planar surface. The organization of Chl is controlled by adjusting the brush grafting density and polymerization time. For dense brushes, the C, N, S elemental composition remains constant throughout the 36 nm brush layer until the underlying gold substrate is approached. However, for either reduced density brushes (mean thickness ∼20 nm) or mushrooms grown with reduced grafting densities (mean thickness 6-9 nm), elemental intensities decrease continuously throughout the brush layer, because photoelectrons are less strongly attenuated for such systems. For all brushes, the fraction of positively charged nitrogen atoms (N+/N0) decreases with increasing depth. Chl binding causes a marked reduction in N+/N0 within the brushes and produces a new feature at 398.1 eV in the N1s core-line spectrum assigned to tetrapyrrole ring nitrogen atoms coordinated to Zn2+. For all grafting densities, the N/S atomic ratio remains approximately constant as a function of brush depth, which indicates a uniform distribution of Chl throughout the brush layer. However, a larger fraction of repeat units bound to Chl is observed at lower grafting densities, reflecting a progressive reduction in steric congestion that enables more uniform distribution of the bulky Chl units throughout the brush layer. In summary, XPS depth-profiling using a GCIS is a powerful tool for characterization of these complex materials.

Cryogel with Modular and Clickable Building Blocks: Toward the Ultimate Ideal Macroporous Medium for Bacterial Separation.

The lack of practical platforms for bacterial separation remains a hindrance to the detection of bacteria in complex samples. Herein, a composite cryogel was synthesized by using clickable building blocks and boronic acid for bacterial separation. Macroporous cryogels were synthesized by cryo-gelation polymerization using 2-hydroxyethyl methacrylate and allyl glycidyl ether. The interconnected macroporous architecture enabled high interfering substance tolerance. Nanohybrid nanoparticles were prepared via surface-initiated atom transfer radical polymerization and immobilized onto cryogel by click reaction. Alkyne-tagged boronic acid was conjugated to the composite for specific bacteria binding. The physical and chemical characteristics of the composite cryogel were analyzed systematically. Benefitting from the synergistic, multiple binding sites provided by the silica-assisted polymer, the composite cryogel exhibited excellent affinity toward S. aureus and Salmonella spp. with capacities of 91.6 × 107 CFU/g and 241.3 × 107 CFU/g in 0.01 M PBS (pH 8.0), respectively. Bacterial binding can be tuned by variations in pH and temperature and the addition of monosaccharides. The composite was employed to separate S. aureus and Salmonella spp. from spiked tap water, 40% cow milk, and sea cucumber enzymatic hydrolysate, which resulted in high bacteria separation and demonstrated remarkable potential in bacteria separation from food samples.

Enhanced stability in pseudocapacitors: Synthesis and characterization of a novel cathode material incorporating cinnamate and ferrocenyl functional groups

This study reports the synthesis of a novel block copolymer, PEO-PFc-PCA, comprising cinnamic acid and ferrocene units via Atom Transfer Radical Polymerization (ATRP), and its application as a positive electrode material in pseudocapacitors. Ferrocene functions as redox-active sites for energy storage, while cinnamic acid, when crosslinked under UV light, forms a nano-network that reduces ferrocene leaching, thereby enhancing the stability and lifespan of the pseudocapacitors. Comprehensive structural characterization, including nuclear magnetic resonance and UV–visible spectroscopy, was conducted on PEO-PFc-PCA. Electrochemical tests—cyclic voltammetry, galvanostatic charge/discharge, and electrochemical impedance spectroscopy—revealed that UV crosslinking improved the electrochemical performance, indicated by a slight increase in current and extended charging plateaus. Specific capacitance and energy density increased by 10 % post-crosslinking, demonstrating improved energy storage capacity. Nyquist plots showed reduced internal and charge transfer resistance after crosslinking, enhancing the electrochemical pathway. Stability tests indicated that crosslinked PEO-PFc-PCA retained 90.1 % of its capacitance after 3000 cycles, compared to 86.6 % pre-crosslinking, highlighting its superior longevity. This research presents a promising approach to enhancing pseudocapacitor energy storage through cinnamic acid photopolymerization, potentially benefiting broader pseudocapacitive electrode designs.

Unusual Stability of an End-on Superoxido Copper(II) Complex under Ambient Conditions.

Superoxido copper complexes play an important role as usually short-lived intermediates in biology and chemistry. The unusual stability of an end-on superoxido copper complex observed in an oxygen-enhanced atom transfer radical polymerization (ATRP) led to a detailed mechanistic investigation of the formation of [CuII(Me6tren)(O2⋅-)]+ (Me6tren=tris(2-dimethyl-aminoethyl)amine) under ambient conditions. The persistence of the superoxido copper complex could be explained by a reaction cycle including the peroxido complex [(Me6tren)2CuII 2(O2)]2+ together with [CuI(Me6tren)(DMSO)]+ and [CuII(Me6tren)(OH)]+ in the overall reaction.

Efficient biocompatible drug carrier: Lignin-based nanogel amplifies Curcumin's cytotoxic effects and induces apoptosis in brain and lung cancer cell lines

This study focuses on the biological effects of size-tunable nanogel based on the natural polymer named lignin. The flexibility of the nanogel to act under variable conditions makes it a promising smart carrier in nanomedicine. Through the “grafting from” approach, it was synthesized by atom transfer radical polymerization (ATRP) method, loaded with curcumin (an anticancer herbal compound) and has been applied to treat two cell lines (A549 and U87MG). Treatment of cells with free curcumin and curcumin-loaded nanogel demonstrated significant differences in IC50 values. The values of free curcumin were 48.23 μM for A549 cells and 36.54 μM for U87MG cells, while the values of curcumin-loaded nanogel were 25.95 μM for A549 cells and 25.65 μM for U87MG cells, respectively. This indicates that the nanogels enhanced the cytotoxic effects of curcumin on both cancerous cell lines.Furthermore, the expression of apoptosis associated genes was evaluated. Under the effects of curcumin-loaded nanogel, the expression of caspase 3 and caspase 9 genes in the A549 cell line increased by 2.3-fold and 1.41-fold, respectively. Additionally, the expression of the pro-apoptotic gene Bax increased by 1.29-fold, while the anti-apoptotic gene Bcl2 decreased by 0.315-fold. Similarly, in U87MG cells, the expression of caspase 3 and caspase 9 genes increased by 6.49-fold and 2.08-fold, respectively, while Bcl2 decreased by 0.023-fold. The changes in gene expression patterns indicate the induction of apoptosis in both cell lines when exposed to curcumin-loaded nanogels. The results of flow cytometry confirmed an increase in apoptosis in the presence of curcumin-loaded nanogels.

An anchor-inspired interface for improving interfacial properties of carbon fiber-reinforced high-performance thermoplastic composites

Carbon fiber-reinforced thermoplastic composites are promising materials with many application prospects. However, surface inertness of CFs weakens the interfacial properties of these composites. Therefore, in this study, an anchor-inspired structure was designed and grafted onto CFs by using an anchor-inspired segmented copolymer, comprising of polyimide as the “chain” and polyhedral oligomeric silsesquioxane (POSS) as the “anchor”. In combination with atom transfer radical polymerization with the advantage of controllable molecular weight, degree of polymerization of the anchor-shaped structure with the best compatibility with poly (phthalazinone ether nitrile ketone) (PPENK) resin was pre-determined through molecular dynamics simulations, which reduced the experimental costs. The results of X-ray photoelectron spectroscopy indicated the successful connection of the numerous anchor-shaped structures to the CFs. Compared to composite made of origin fibers and PPENK, the interfacial shear strength at the microscopic level and interlaminar shear strength at the macroscopic level of grafted CF and PPENK composite increased by 184.9 % and 44.2 %, respectively. This is mainly attributed to the synergistic effect of mechanical interlocking and interfacial interaction between the anchor-shaped structure and the PPENK resin. This study serves as a feasible path to enhance the interfacial adhesion of composites by designing an anchor-shaped structure of organic macromolecules and inorganic nanoparticles on CFs.