Electrostatic Cross-linking Research Articles

Significantly enhanced high-temperature energy storage capacity for polyetherimide-based nanocomposites via energy level modulation and electrostatic crosslinking

In the field of electrostatic energy storage, polymers exhibit notable advantages, including high breakdown strength (Eb) and fast charge/discharge rates. However, at elevated temperatures, their discharge energy density (Ud) decreases due to reduced Eb and increased electrical conductivity losses. We herein integrate fluoro-functionalized polyimide (PFI) shell-modified Al2O3 nanoparticles (PFI@Al2O3) with polyetherimide (PEI) to form a trap-rich electrostatic crosslinked network. By energy level modulation and electrostatic crosslinking, the PFI layer enables to capture charges and acts as crosslinking sites, while the wide-bandgap Al2O3 introduces energy barriers that inhibit charge injection and migration. This sophisticated dual-interface design enhances Eb and facilitates dual capture of electrons and holes, thus effectively reducing leakage current and conduction losses. Surprisingly, the composites prepared using this method exhibit an energy density of 7.24 J/cm³ at 150 °C, with a charging-discharging efficiency of 83.58 %. Moreover, it maintains stability even after 105 extended charge-discharge cycles under harsh conditions (200 kV/mm and 150 °C). This work lays a solid foundation for electrostatic energy storage at elevated temperature.

3D-printed artificial cornea featuring aligned fibrous structure and enhanced mechanical strength

The global shortage of donor eye bank tissue has significantly impeded advancements in biomaterial for corneal implantation. To address this issue, we have developed a 3D-printed artificial cornea using a composite hydrogel of sodium alginate (SA) and cellulose nanofibers (CNF), crosslinked with poly-L-lysine-co-L-glutamic acid (PLL80GA20, PG) and calcium chloride (CaCl2, CC). The 2 wt% SA/CNF composite hydrogel offers several advantages, including low toxicity, cost-effectiveness, excellent printability, and high mechanical strength, even with low crosslinker concentrations. The PG was synthesized via ring-opening polymerization of L-glutamate N-carboxyl anhydride (BGNCA) and L-lysine N-carboxyl anhydride (CBZNCA). The purity of the monomers was verified through DSC analysis, revealing a melting point of 97 ℃. The molecular weight of the synthesized PG was determined to be 47 kDa. A dual crosslinking strategy was employed, starting with electrostatic crosslinking, followed by ionic crosslinking using varying concentrations of PG and CC at different effective charge concentrations of 6.25 mM, 12.25 mM, and 25 mM. The hydrogel and 3D-printed cornea were comprehensively evaluated for chemical structure, surface functional groups, water content, mechanical strength, orientation, cytotoxicity, biocompatibility, and transparency. Notably, the inclusion of PG significantly enhanced the mechanical properties of the 3D-printed cornea, with the hydrogel achieving a storage modulus of 2,360 kPa at 6.25 mM of PG/CC, while maintaining over 95% water content. The artificial cornea demonstrated 86% transparency, and the cell viability showed 96% viable on Day 7 with degradation rate of 35.9% in 28 days. The superior hydrophilicity, transparency, and mechanical strength of the printed hydrogel highlights its potential for the development of full-thickness corneal structures, making it a promising candidate for future corneal implants.

Fabrication of hexagonal platelets of Fe3O4/Fe2O3/C modified with polyacrylamide for excellent electromagnetic wave absorption

In order to improve the weak dielectric loss capability and poor impedance matching of Fe3O4, the hexagonal plates of Fe3O4/Fe2O3/C nanocomposites were rationally constructed in this paper by utilizing electrostatic attraction and cross-linking, using polyacrylamide (PAM) as templating agent and viscosity modifier. The stacked hexagonal plates constructed a conductive network and utilized the structural properties of Fe3O4 to promote the transfer and jump of free electrons, which effectively improved the conduction loss. The heterogeneous interface was effectively constructed due to the presence of Fe2O3 and trace carbon, while the transfer and leap of free electrons promoted the generation of interfacial polarization, resulting in magnetoelectric coupling and effective improvement of polarization loss. The results show that the effective absorption broadband reaches 4.08 GHz when the matching thickness of the composite is 2 mm. A minimum reflection loss of −43.79 dB is realized at a matching thickness of 1 mm. The PAM modification proved to be an effective means to modulate the morphology and composition of the materials.

Did the exposure of coacervate droplets to rain make them the first stable protocells?

Membraneless coacervate microdroplets have long been proposed as model protocells as they can grow, divide, and concentrate RNA by natural partitioning. However, the rapid exchange of RNA between these compartments, along with their rapid fusion, both within minutes, means that individual droplets would be unable to maintain their separate genetic identities. Hence, Darwinian evolution would not be possible, and the population would be vulnerable to collapse due to the rapid spread of parasitic RNAs. In this study, we show that distilled water, mimicking rain/freshwater, leads to the formation of electrostatic crosslinks on the interface of coacervate droplets that not only suppress droplet fusion indefinitely but also allow the spatiotemporal compartmentalization of RNA on a timescale of days depending on the length and structure of RNA. We suggest that these nonfusing membraneless droplets could potentially act as protocells with the capacity to evolve compartmentalized ribozymes in prebiotic environments.

Linear and nonlinear interfacial rheology of responsive microgels at the oil-water interface

Microgelation can significantly enhance the interfacial activity of polysaccharide and the ability to stabilize emulsion, but the interfacial behaviour of microgels and the intrinsic mechanism of stabilizing emulsion is not fully understood. In this study, chitosan microgels (h-CSMs) with uniform size were successfully prepared by electrostatic crosslinking hydrophobically modified chitosan (h-CS) with sodium phytate (SP) using microfluidic technique. The microfluidic conditions for fabricating of h-CSM were optimized: the mass ratio of h-CS: SP = 5: 1 with h-CS concentration of 0.5 mg/ml, and the pressure ratio of Ph-CS (Pa):PSP (Pa) = 1600:1000. The prepared h-CSMs were pH-responsive, with a swollen state at pH 5 and a shrunken state at pH 3 and 7. Further, the interfacial adsorption kinetics, and the interfacial rheology particularly the nonlinear interfacial rheology were systematically studied. The instantaneous Si-factor was proposed to describe the nonlinear responses of the microgel interface during an individual dilatational oscillation cycle. The results showed that microgelation significantly improved the interfacial ability of chitosan molecules at the oil-water interface. The h-CSM interface exhibited strain-softening response during extension and strain-hardening response during compression. The interface formed by h-CSMs under the swollen state had higher viscoelastic modulus, lower degree of nonlinearity and higher emulsifying capacity compared to that formed under the shrinking state. Low ionic strength significantly increased the viscoelastic modulus and reduced the nonlinearity and enhanced emulsifying capacity of the h-CSM interface, whereas high ionic strength disrupted the interaction between the h-CSMs and increased the nonlinear of the h-CSM interface due to too strong electrostatic screening effect.

Understanding Na+ Diffusion, Physicochemical Behavior, and Electrochemical Performance of a Gel Polymer Electrolyte.

Gel polymer electrolytes (GPEs) represent a credible alternative to organic liquid electrolytes (LEs) for safer sodium metal batteries. As a compromise between solid polymer electrolytes and LEs, GPEs ensure a good ionic conductivity, improve the electrolyte/electrode interface, and prevent solvent leaks. Herein, a GPE based on acrylate-bifunctionalized polyethylene glycol chains mixed with an ether solvent (TEGDME) and a polyethylene glycol diacrylate (PEG600DA) in a 50/50 wt % ratio was prepared by ultraviolet photopolymerization. Sodium bis(fluorosulfonyl)imide salt (NaFSI) was added at different concentrations to study its interactions with the solvent and/or the cross-linked polymer. Infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry, and swelling ratio characterizations were combined to determine the physicochemical properties of the GPE. Complementary characterizations including electrochemical impedance spectroscopy, chronopotentiometry, and cyclic voltammetry allowed correlating the physicochemical properties of the GPE to its electrochemical performance. Then, improvements were obtained by careful combination of its components. The cross-linking agent allowed us to obtain a polymer matrix that traps the organic solvent and prevents leakage. Such a solvent inclusion reduces the rigidity of the membrane and lowers its viscosity, offering a room temperature ionic conductivity of 4.8 × 10-4 Ω-1 cm-1. The control of polymer's tortuosity leads to a stable cycling vs sodium metal over several hundred hours without increase of the polarization. Finally, optimization of the salt loading plays a major role in electrostatic cross-linking, leading to an improvement of the mechanical properties of the GPE without reducing its conductivity.

Innovative method for producing plant-based meat analogs: Acid/calcium-induced internal gelation of potato protein/alginate composites

When creating plant-based meat analogs, it is often challenging to mimic the structural and textural attributes of real meat products during the cooking process. In this study, we investigated the potential of using potato protein/calcium alginate composite gels to formulate plant-based meat analogs. These gels provide a semi-solid texture at ambient temperature that remains intact during cooking because the electrostatic crosslinks are resistant to heat. Composite gels consisting of potato protein (10 wt%) and alginate (0–2 wt%) were prepared using the internal gelation method. This method involves dispersing an insoluble form of calcium (CaHPO4) throughout the protein-polysaccharide matrix and then using glucono-delta-lactone (GDL) to slowly lower the pH, thereby releasing the Ca2+ ions evenly throughout the system. The calcium alginate increased the strength of the potato protein gels and provided structural resistance to heat. Appreciable water loss occurred during cooking for simple calcium alginate gels, but this was prevented when potato proteins were present. Increasing the alginate concentration from 0 to 1.5 % increased the strength of the composite gels but higher levels promoted phase separation and network disruption, which reduced the gel strength. Heating did not appreciably alter the microstructure of the composite gels, but it did alter that of the pure potato protein gels. Finally, the potential of the composite gels as plant-based meat analogs was assessed by comparing their thermal denaturation and textural properties to those of real chicken breast. The potato protein/alginate composites were shown to simulate the thermal denaturation and textural changes of real chicken during the cooking process. Overall, our results suggest that calcium alginate gels may be useful in the formulation of plant-based meat products with improved cooking properties.

Minimally Invasive Delivery of Percutaneous Ablation Agent via Magnetic Colloidal Hydrogel Injection for Treatment of Hepatocellular Carcinoma.

Percutaneous thermotherapy, a minimally invasive operational procedure, is employed in the ablation of deep tumor lesions by means of target-delivering heat. Conventional thermal ablation methods, such as radiofrequency or microwave ablation, to a certain extent, are subjected to extended ablation time as well as biosafety risks of unwanted overheating. Given its effectiveness and safety, percutaneous thermotherapy gains a fresh perspective, thanks to magnetic hyperthermia. In this respect, an injectable- and magnetic-hydrogel-construct-based thermal ablation agent is likely to be a candidate for the aforementioned clinical translation. Adopting a simple and environment-friendly strategy, a magnetic colloidal hydrogel injection is introduced by a binary system comprising super-paramagnetic Fe3O4 nanoparticles and gelatin nanoparticles. The colloidal hydrogel constructs, unlike conventional bulk hydrogel, can be easily extruded through a percutaneous needle and then self-heal in a reversible manner owing to the unique electrostatic cross-linking. The introduction of magnetic building blocks is exhibited with a rapid magnetothermal response to an alternating magnetic field. Such hydrogel injection is capable of generating heat without limitation of deep penetration. The materials achieve outstanding therapeutic results in mouse and rabbit models. These findings constitute a new class of locoregional interventional thermal therapies with minimal collateral damages.

Postbiotic characterization of a potential probiotic yeast isolate, and its microencapsulation in alginate beads coated layer-by-layer with chitosan

Considering biosafety concerns and survivability limitations of probiotics (PRO) under different stresses, application of postbiotics and encapsulated PRO has received considerable attentions. Accordingly, the objective of the present study was to investigate the postbiotic capabilities of a potential PRO yeast isolate and the effect of encapsulation with alginate (Alg) and chitosan (Ch) on its survival under SGI conditions. Sequencing results of the PCR products led to the identification of Saccharomyces cerevisiae as the selected potential PRO yeast isolated from wheat germ sourdough. High survival of the isolate under simulated gastrointestinal (SGI) conditions (95.74%), its proper adhesion abilities, as well as its potent inhibitory activity against Listeria monocytogenes (75.84%) and Aspergillus niger (77.35%) were approved. Interestingly, the yeast cell-free supernatant (CFS) showed the highest antioxidant (84.35%) and phytate-degrading (56.19%) activities compared to the viable and heat-dead cells of the isolate. According to the results of the HPLC-based assay, anti-ochratoxin A (OTA) capability of the dead cells was also significantly (P < 0.05) higher than that of the viable cell. Meanwhile, the yeast CFS had no anti-OTA and antimicrobial activities against the foodborne bacteria and fungi tested. Further, microencapsulation of the yeast isolate in Alg beads coated layer-by-layer with Ch (with 77.02% encapsulation efficacy and diameter of 1059 μm based on the field emission scanning electron microscopy analysis) significantly enhanced its survivability under SGI conditions in comparison with the free cells. In addition, electrostatic cross-linking between negatively charged carboxylic groups of Alg and positively charged amino groups of Ch was verified in accordance with Fourier transform infrared and zeta potential data. Human and/or industrial food trials in future are needed for practical applications of these emerging ingredients.

PH-triggered chitosan-sodium caseinate nanocarriers with charge-switching property: Characterization and applications in dental care

As a typical biofilm disease, dental caries is a public healthcare problem and high sugar diets increase the risk of dental caries. Cationic nanomaterials play an important role in targeting and removing of biofilms, but their negative effects on normal cells have always caused widespread concern. In this work, pH-triggered charge-switching nanoparticles (SC&CS NPs) with selectable targeting were skillfully constructed by electrostatic adsorption and chemical cross-linking of sodium caseinate (SC) and chitosan (CS) to develop functional foods. SC&CS NPs were negatively charged and stable at pH 7.4. Once encountering in acidic microenvironment below pH 5.7, the potential of SC&CS NPs converted to positive. Based on this property, SC&CS NPs could identify the infected sites of biofilms to selectively target bacteria, while not interacting with cells in the normal physiological environment, thereby avoiding damage to normal cells. Besides, SC&CS NPs were excellent delivery systems that could effectively encapsulate bioactive ingredients with high loading efficiency (12.16 ± 0.04%) and release bioactive ingredients on demand. Moreover, after being encapsulated by SC&CS NPs, the antibacterial and anti-biofilm activities of bioactive ingredients were significantly improved. The charge-switching nanomaterials are expected to provide a safer, more effective, and smarter strategy for functional foods.

A novel strategy to prepare high performance multifunctional composite films by combining electrostatic assembly, crosslinking, topology enhancement and sintering.

Currently, polymer-fiber composite films face the challenge of striking a balance between good mechanical properties and multi-functionalities. Here, aramid fibers (ANFs), chitosan (CS) dendritic particles, and silver nanowires (AgNWs) were used to create high-performance multifunctional composite films. AgNWs and polymer dendritic particles form an interpenetrating segregated network that ensures both a continuous conductive filler and a polymer network. Electrostatic assembly eliminates repulsion between negatively charged ANFs, cross-linked CS particles generate a stable three-dimensional network, and a "brick-mortar" structure composed of multiple materials contributes to topological enhancement. Sintering encourages local overlap and fusing of the AgNWs while reducing their internal flaws. Based on the above strategy, these films achieve a strength of 306.5 MPa, a toughness of 26.5 MJ m-3, and a conductivity of 392 S cm-1. Density functional theory (DFT) and Comsol simulations demonstrate that the introduction of CS thin layers leads to strong hydrogen bonds and three-dimensional continuous conductive networks. With its outstanding mechanical and electrical properties, the AgNW@ANF/CS-CH film demonstrates excellent electromagnetic shielding (22 879.1 dB cm2 g-1) and Joule heating (70 °C within 10 s) capabilities. This work presents a novel approach to fabricate high-performance conductive films and expand their potential applications in lightweight wearable electronics and electrothermal therapy.

Tribopositive biomass toward enhanced stretchability and ionic conductivity of energy harvesters and sensors

At present, there is a rapidly growing demand for high-performance energy harvesters as power supply for wearable devices. Herein, an advanced tribopositive biomass film is developed by tuning the hygroscopicity and chelation of sodium carboxymethyl cellulose (SC) for use in triboelectric nanogenerator. The electrostatic ionic cross-linking of CuCl2 and SC and the hygroscopic plasticizing of glycerol increase the stretchability and electrical conductivity of SC by 47.8 and 7.5 × 103-folds, respectively. Given the trapped water content and chelation density, significantly improved tribopositivity, open circuit voltage (160 V), charge quantity (125 µC·m−2) and short-circuit current density (68.8 mA·m−2), representing an increase by 10, 10.9, and 28.8-folds, respectively. Further, the power density reaches 5.35 W·m−2, being higher than most biomass-based devices. Given the high electrical conductivity, the SC film also functions as current collector, thus avoiding the delamination issue in long-term device operation. In addition, the significantly enhanced stretchability of SC (430% of elongation at break), makes it an ideal candidate for wearable devices for effectively harvesting the energy from human motion while monitoring the relative humidity, thus paving the way toward sustainable alternatives for high performance wearable devices.

Incorporating amphiphilic modifier into PVDF membrane through in-situ electrostatic crosslinking for efficient oil-water separation

Constructing stable amphiphilic membrane surfaces in a facile and controlled way is highly desired for fabrication of antifouling water purification membranes. Herein, inspired by adhesives of sandcastle worms, we proposed an in-situ electrostatic crosslinking method to incorporate amphiphilic modifiers into poly (vinylidene fluoride) membranes. Pluronic F127 grafted with positively charged quaternary ammonium groups are added into the casting solution, while perfluorosulfonic acid bearing negatively charged sulfonic acid groups and perfluorocarbon chains are dissolved in the coagulation bath. During non-solvent induced phase separation process, electrostatic crosslinking between quaternary ammonium and sulfonic acid led to the in-situ formation of amphiphilic modifiers on membrane surfaces and pore walls. The resulting membrane exhibits high water permeance up to 625 Lm−2h−1 bar−1 and superior antifouling performance with total flux decline ratio of 2 % and flux recovery ratio of 99.3 % for oil-water separation. Besides, the membrane displays excellent structural stability and self-cleaning properties against highly viscous crude oils.

Chitosan-alginate sponge with multiple cross-linking networks for adsorption of anionic dyes: Preparation, property evaluation, mechanism exploration, and application

A chitosan-alginate sponge (CAS) with multiple cross-linking networks was developed using chitosan, sodium alginate, polyvinyl alcohol, and glutaraldehyde to adsorb and enrich the anionic dyes form the food samples. The multiple networks in CAS refer to the electrostatic cross-linking network, hydrogen bonding cross-linking network, and covalent cross-linking network. Compared with pure chitosan and alginate sponges, the CAS showed better three-dimensional network structure, mechanical behavior, and stability, which is benefit by multiple cross-linking networks. The physical and chemical properties of CAS were systematically studied by a series of characterizations. The adsorption performance of CAS on anionic dyes was inspected with different dye concentration, time, temperature, and pH conditions. CAS exhibited a good and stable adsorption property to amaranth, carmine, and sunset yellow with the saturation adsorption capacity of 94.34, 111.5, and 80.05 mg∙g–1, respectively. Furthermore, CAS performed outstanding selectivity to anionic dyes with the selectivity factor up to 16.99. Through electrostatic potential analysis, it is inferred that CAS mainly adsorbs anionic dyes through electrostatic interactions. CAS showed satisfactory reusability, maintaining 97 %–99 % of adsorption performance after six cycles of recycling. Finally, CAS was combined with high-performance liquid chromatography for the enrichment and detection of anionic dyes in candy and cocktail samples, achieving the enrichment factor up to 84.77.

Synergistic improvement of mechanical and adsorption properties by constructing physical multiple-network hydrogel for removing uranium

Biomass hydrogels, a kind of favorable adsorbents, have been applied extensively in uranium removal due to its three-dimensional network structure. However, it usually can not maintain good mechanical properties and adsorption properties simultaneously. Furthermore, chemical hydrogels, due to the usage of hazardous chemical crosslinkers and initiators, would inevitably result in secondary environmental pollution during its preparation. To improve the poor mechanical property of biomass polymer gellen gum (GG) as an adsorbent, while maintaining its good adsorption capacity, a multiple-network hydrogel (GG-CS-Ca) was physicallly constructed by self-assembly using GG and another cationic polyelectrolyte chitosan (CS) together with Ca2+ in this work. The structure, morphology and stability were disclosed by FTIR, SEM, EDS, XPS and TG analysis. Furthermore, its adsorption properties were systematically investigated by static and dynamic adsorption testing. The results indicated that the mechanical strength of GG-CS-Ca was improved compared with as-prepared adsorbent GG-Ca while its adsorption capacity maintained at a higher level which was twice of the mechanically reinforcing GG-based adsorbent GG-CMKGM. It indeed achieved the synergistic improvement of mechanical strength and adsorption capacity. Moreover, it showed favorable acid-resistant stability because of the electrostatic crosslinking of negative GG and positive CS under high acidic condition. The dynamic adsorption analysis certified that it could be applied in actual uranium removing as an adsorbent and the application parameter could be predicted by Thomas and Yoon-Nelson model.

Dual-reinforcement strategy: Fabrication of CMC-Na/SPI aerogel-templated oleogels through electrostatic adsorption and chemical crosslinking

Recently, the use of aerogel templates for preparing oleogels has gained significant attention. In this study, we fabricated a CMC-Na/SPI composite aerogel-templated oleogel using a dual-reinforcement strategy involving electrostatic adsorption and chemical crosslinking. Citric acid was utilized as both a pH regulator and a crosslinking agent. Firstly, it adjusted the pH of the solution, facilitating the formation of soluble complexes through electrostatic interactions between SPI and CMC-Na. Secondly, it enhanced the strength of the oleogel by crosslinking the cellulose. Scanning electron microscopy images revealed the formation of multiple layers of SPI along the CMC-Na framework as the SPI content increased. Mechanical tests demonstrated that the oleogel exhibited a maximum compressive strength of 0.343 MPa and a Young's modulus of 0.604 MPa. The oleogels also displayed excellent strain memory effect and remarkable structural resilience. Furthermore, the CMC-Na/SPI composite aerogel templates exhibited outstanding oil absorption capacity (53.8 g/g aerogel), oil holding capacity (77.8%), and thermal stability. This study introduces a novel approach for designing protein/cellulose-based aerogel-templated oleogels, which have the potential to replace fat in artificial meat products.

Solvent-less carboxymethylation-induced electrostatic crosslinking of chitosan

The successful N-carboxymethylation and concomitant crosslinking of solid chitosan upon heating its mixture with solid monochloroacetic acid, without the use of solvents or catalysts, is reported. The N-carboxymethylation was confirmed through the analysis of the partially depolymerized product using NMR spectroscopy, as well as a control reaction with lysine. This transformation was facilitated by the nucleophilic nature of the free amine group in the repeating unit of chitosan, which possesses lone pair of electrons capable of attacking the carbon center bearing the leaving group and displacing the leaving group in a concerted manner. The crosslinking, on the other hand, was established by the observed insolubility in aqueous acidic solutions, even when subjected to prolonged heating at 60 °C. This crosslinking occurs due to the electrostatic interactions between the carboxylate groups and the adjacent ammonium groups, as supported by evidence from FTIR spectroscopy and a control reaction involving ethyl chloroacetate. The resulting crosslinked carboxymethyl chitosan demonstrated its usefulness in the adsorption of methyl orange and fluorescein, as well as functioning as an organic catalyst for aza-Michael addition, Hantzsch reaction, and substituted perimidine synthesis.

PH-Responsive Dynaplexes as Potent Apoptosis Inductors by Intracellular Delivery of Survivin siRNA.

Gene knockdown by siRNA offers an unrestricted choice of targets and specificity based on the principle of complementary Watson-Crick base pairing with mRNA. However, the negative charge, large molecular size, and susceptibility to enzymatic degradation of siRNA impede its successful transfection, hence limiting its potential for therapeutic use. The development of efficient and safe siRNA transfection agents is, therefore, critical for siRNA-based therapy. Herein, we developed a protein-based biodynamic polymer (biodynamer) that showed potential as a siRNA transfection vector, owing to its excellent biocompatibility, easy tunability, and dynamic polymerization under acidic environments. The positively charged biodynamers formed stable dynamic nanocomplexes (XL-DPs, hydrodynamic diameter of approximately 104 nm) with siRNA via electrostatic interactions and chemical cross-linking. As a proof of concept, the optimized XL-DPs were stable in physiological conditions with serum proteins and demonstrated significant pH-dependent size change and degradability, as well as siRNA release capability. The minimal cytotoxicity and excellent cellular uptake of XL-DPs effectively supported the intracellular delivery of siRNA. Our study demonstrated that the XL-DPs in survivin siRNA delivery enabled potent knockdown of survivin mRNA and induced notable apoptosis of carcinoma cells (2.2 times higher than a lipid-based transfection agent, Lipofectamine 2000). These findings suggested that our XL-DPs hold immense potential as a promising platform for siRNA delivery and can be considered strong candidates in the advancement of next-generation transfection agents.

Aqueous solution stability and aggregation of water-dispersed polyester: Complex interactions with concentration, temperature, and electrolytes

Amphiphilic polymer water-dispersed polyester (WPET) has promising applications in the textile field. However, the stability of the WPET solution is easily influenced by external factors because of the potential interactions among the molecules of WPET. This paper focuses on the effects of concentration, temperature, and electrolyte on WPET aggregation behavior, and reveals the possible aggregation mechanism. The results show that WPET concentration, temperature, and electrolyte play important and complex roles in controlling the aggregation behaviors of the WPET. As temperature increases, the WPET can be better dispersed and less aggregated. In addition, Mg2+ and Ca2+ can accelerate the coagulation of WPET through electrostatic interaction and cross-linking with WPET. The addition of the chelating agent can greatly reduce the aggravating effect of Mg2+ or Ca2+ in solution on WPET molecular coagulation. These fundamental studies of WPET aggregation behavior can be used to effectively control and improve the stability of WPET solution.

Ionically cross-linked micro-sized hydrogels with encapsulated drug: Structure, cell uptake kinetics and cytotoxicity

Micro-sized hydrogels synthesized by electrostatic cross-linking of anionic alginate with Ca2+ cations were additionally loaded with cationic fluorescent dye Rhodamine 6B or cationic antitumor antibiotic doxorubicin. Forming complexes with Ca2+ alginate hydrogels, doxorubicin retained or even reduced its toxicity to tumor and normal cells. The results can be used to design containers for the encapsulation and delivery of drugs and control their interaction with cells.