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A promising strategy to improve the effectivity of anticancer treatment and decrease its side effects is to modulate drug release by using nanoparticulates (NPs) as carriers. In this study, methotrexate-loaded chitosan–polyanion nanoparticles were produced by polyelectrolyte complexation assisted by high-intensity sonication, using several anionic polymers, such as the sodium and potassium salts of poly(maleic acid-alt-ethylene) and poly(maleic acid-alt-octadecene), here named PAM-2 and PAM-18, respectively. Such NPs were analyzed and characterized according to particle size, polydispersity index, zeta potential and encapsulation efficiency. Likewise, their physical stability was tested at 4 °C and 40 °C in order to evaluate any change in the previously mentioned particle parameters. The in vitro methotrexate release was assessed at a pH of 7.4, which simulated physiological conditions, and the data were fitted to the heuristic models of order one, Higuchi, Peppas–Sahlin and Korsmeyer–Peppas. The results revealed that most of the MTX-chitosan–polyanion NPs have positive zeta potential values, sizes <280 nm and monodisperse populations, except for the NPs formed with PAM-18 polyanions. Further, the NPs showed adequate physical stability, preventing NP–NP aggregation. Likewise, these carriers modified the MTX release by an anomalous mechanism, where the NPs formed with PAM-2 polymer led to a release mechanism controlled by diffusion and relaxation, whereas the NPs formed with PAM-18 led to a mainly diffusion-controlled release mechanism.

In this study, we report an easy approach for the production of aqueous dispersions of C60 fullerene with good stability. Maleic acid copolymers, poly(styrene-alt-maleic acid) (SM), poly(N-vinyl-2-pyrrolidone-alt-maleic acid) (VM) and poly(ethylene-alt-maleic acid) (EM) were used to stabilize C60 fullerene molecules in an aqueous environment by forming non-covalent complexes. Polymer conjugates were prepared by mixing a solution of fullerene in N-methylpyrrolidone (NMP) with an aqueous solution of the copolymer, followed by exhaustive dialysis against water. The molar ratios of maleic acid residues in the copolymer and C60 were 5/1 for SM and VM and 10/1 for EM. The volume ratio of NMP and water used was 1:1.2–1.6. Water-soluble complexes (composites) dried lyophilically retained solubility in NMP and water but were practically insoluble in non-polar solvents. The optical and physical properties of the preparations were characterized by UV-Vis spectroscopy, FTIR, DLS, TGA and XPS. The average diameter of the composites in water was 120–200 nm, and the ξ-potential ranged from −16 to −20 mV. The bactericidal properties of the obtained nanostructures were studied. Toxic reagents and time-consuming procedures were not used in the preparation of water-soluble C60 nanocomposites stabilized by the proposed copolymers.

Styrene maleic acid lipid nanoparticles (SMALPs) arise from amphipathic styrene maleic acid (SMA) copolymer encapsulation of membranes into polymer‐lipid nanodiscs, structures applied in the native extraction of membrane proteins (MPs). Strategies to immobilize SMALPs via their polymer belt onto surfaces allow the biophysical study of MPs without direct protein‐surface anchoring. In this work, reversible addition‐fragmentation chain transfer (RAFT) polymerization is used to synthesize a library of diblock SMA copolymers to determine the optimal sequence for SMALP assembly. The further ability of trithiocarbonates (T) and attached (Z)‐end‐groups, generated by RAFT polymerization, to tether SMALPs to gold surfaces via sulfur‐gold bonds is evaluated. Improved DMPC liposome solubilization is achieved with a hydrophilic (Z)‐end‐group, shorter polystyrene block and lower molecular weight for diblock R‐(Sty)‐b‐(Sty‐alt‐MA)‐T‐Z polymers. Quartz crystal microbalance with dissipation monitoring (QCM‐D) and atomic force microscopy (AFM) revealed that diblock SMA polymers bound to gold as a micellular film, irrespective of the presence of the trithiocarbonate group. SMALPs, however, showed an enhanced gold affinity when terminated by a trithiocarbonate and hydrophilic RAFT (Z)‐end‐group compared to end‐group removed SMALPs, the latter exhibiting nonspecific gold adhesion. These findings offer a new approach in utilizing RAFT end‐groups of nanodisc assembling polymers for label‐free analysis of MPs. Styrene maleic acid lipid nanoparticles (SMALPs) comprised of diblock styrene maleic acid (SMA) copolymers readily tether to gold surfaces. This binding is enhanced when the diblock SMA is functionalized with a trithiocarbonate and hydrophilic (Z)‐end‐group generated through the reversible addition‐fragmentation chain transfer polymerization process.

Detecting and quantifying trace amounts of antibiotics like amoxicillin and oxytetracycline in milk and environmental water samples is crucial for public health and environmental monitoring. This research focuses on developing a novel sorbent for solid-phase extraction (SPE) of amoxicillin and oxytetracycline from milk and environmental water samples, using electrospun graphene oxide-doped poly(acrylonitrile- co -maleic acid) nanocomposite fibers, followed by high-performance liquid chromatography with diode array detection (HPLC-DAD). The fibers were successfully fabricated and characterized using a suite of techniques: SEM-EDX, FTIR, XRD, BET, XPS, TGA, and Raman spectroscopy. The extraction process was optimized by carefully adjusting parameters like desorption solvent (0.60 mL of 0.2 M HCl in methanol), extraction time (60 min), and sample pH (3) to achieve efficient and reliable extraction. Under optimal conditions, the developed method demonstrated good linearity (5–100 µg/L, R² > 0.9925), low detection and quantification limits (1.50 µg/L and 5.0 µg/L for amoxicillin and 1.46 µg/L and 4.8 µg/L for oxytetracycline) and high enrichment factor (21 for amoxicillin and 47 for oxytetracycline). The achievable accuracy and precision of the developed sorbent were satisfying, for incidence, relative recovery range of 90.3–106.3% and 87.6–95.9% with RSD range of 1.9–4.3% and 1.1–4.7% for amoxicillin and oxytetracycline, respectively. The method demonstrates reliable and efficient extraction and quantification of antibiotics from two different classes at maximum residue levels, making it suitable for monitoring antibiotic contamination in food and environmental samples, ultimately promoting better public health outcomes.

The effect of fiber drying on the properties of lignin containing cellulose nanocrystals (LCNC) and nanofibrils (LCNF) produced using concentrated maleic acid hydrolysis of a never dried unbleached mixed hardwood kraft pulp was evaluated. Two drying conditions, i.e., air drying and heat drying at 105 °C were employed. It was found that drying (both air and heat) enhanced acid hydrolysis to result in slightly improved LCNC yields and less entangled LCNF. This is perhaps due to the fact that drying modified the cellulose supermolecular structure to become more susceptible to acid hydrolysis and the enhanced hydrolysis severity at the fiber surface when using dried fibers. Drying substantially improved LCNC crystallinity and LCNF suspension viscoelastic behavior. The present study quantitatively elucidated the effect of pulp drying (either air or heat) on producing cellulose nanomaterials and has practical importance because commercial market pulp (heat dried) is most likely to be used commercially.

Recently, the isolation of chitin nano-crystals (ChNCs) via green methods has received great interests in the scientific research community. In this study, one-pot and eco-friendly process to isolate ChNCs from Metapenaeus ensis shell via solid maleic acid hydrolysis was proposed. It was found that the highest ChNC yield can be reached to 10.42% when at the condition of 75% acid concentration and 110 °C for 3 h, and that the as-prepared ChNC suspensions exhibited extraordinary colloidal stability for 7 months. The corresponding length of ChNCs was 170.6 nm and the carboxylic group content was as high as 0.173 mmol/g. ChNCs were then applied as the efficient and green supports of silver nanoparticles (Ag NPs) and found that ChNCs can help generate Ag NPs with tiny and uniform particle size. The study paves a great potential way to isolate ChNCs from marine crustacean with high colloidal stability and the potential application in the preparation of uniform noble metal nanoparticles.Graphic abstractA one-pot facile and environmental friendly approach to isolate ChNCs from Chitin (Metapenaeus ensis shell as the marine biomass precursors) with high colloidal stability via solid maleic acid hydrolysis is proposed.

In this study, a versatile synthesis of silver nanoparticles of well-defined size by using hydrogels as a template and stabilizer of nanoparticle size is reported. The prepared hydrogels are based on polyvinyl alcohol and maleic acid as crosslinker agents. Three hydrogels with the same nature were synthesized, however, the crosslinking degree was varied. The silver nanoparticles were synthesized into each prepared hydrogel matrix achieving three significant, different-sized nanoparticles that were spherical in shape with a narrow size distribution. It is likely that the polymer network stabilized the nanoparticles. It was determined that the hydrogel network structure can control the size and shape of the nanoparticles. The hydrogel/silver nanohybrids were characterized by swelling degree, Thermal Gravimetric Analysis (TGA), Fourier Transform Infrared (FT-IR), Scanning Electron Microscopy (SEM) and Transmission Electron Microscope (TEM). Antibacterial activity against Staphylococcus aureus was evaluated, confirming antimicrobial action of the encapsulated silver nanoparticles into the hydrogels.

In this work, the durability of chitosan functionalization of cellulosic textile substrates, cotton and cotton/polyester blended fabrics, was studied. Chitosan is a naturally occurring biopolymer that can be produced inexpensively. It should be dissolved in an acidic solution to activate its antimicrobial and other properties, i.e., good biocompatibility, bioabsorbability, wound healing, hemostatic, anti-infective, antibacterial, non-toxic, and adsorptive properties. The application of chitosan to textile products has been researched to achieve antimicrobial properties, but the durability, after several maintenance cycles, has not. Chitosan functionalization was carried out using maleic acid (MA) and 1,2,3,4-butanetetracarboxylic acid (BTCA) as crosslinking and chitosan-activating agents and sodium hypophosphite monohydrate as a catalyst. To determine durability, the fabrics were subjected to 10 maintenance cycles according to ISO 6330:2012 using Reference detergent 3 and drying according to Procedure F. The properties were monitored after the 3rd and 10th cycles. The crosslinking ability of chitosan with cellulosic fabrics was monitored by Fourier infrared spectrometry using the ATR technique (FTIR-ATR). Changes in mechanical properties, whiteness and yellowing, and antimicrobial properties were determined using standard methods. Compared to maleic acid, BTCA proved to be a better crosslinking agent for chitosan.

Polyelectrolyte complexes (PECs) have gained increasing attention in recent decades due to their importance in various applications, such as water treatment and paper processing. These complexes are formed by mixtures of polycations (n+) and polyanions (n−), known as polyelectrolytes (PEs). In this study, a series of PECs were prepared with different molar charge ratios (n−/n+) using biopolymers such as chitosan (lch) and pectin (p) at pH 5, in addition to the synthetic polymer poly(ethylene alt maleic acid) (PEMA) at the same pH. Two types of chitosan—low molecular weight chitosan (lch) and high molecular weight chitosan (hch)—were used as polycations, and these were mixed with two types of pectin with either a high esterification degree (hp) or a low esterification degree (lp), as well as PEMA as polyanions. These components interacted via electrostatic forces to form the following PEC combinations: (lch&lp), (lch&hp), (hch&hp), and (lch&PEMA). The charge density, turbidity, and particle size of the formed PECs were examined to evaluate the influence of molecular weight and mixing speed on the formation process.

A promising tool in membrane research is the use of the styrene–maleic acid (SMA) copolymer to solubilize membranes in the form of nanodiscs. Since membranes are heterogeneous in composition, it is important to know whether SMA thereby has a preference for solubilization of either specific types of lipids or specific bilayer phases. Here, we investigated this by performing partial solubilization of model membranes and analyzing the lipid composition of the solubilized fraction. We found that SMA displays no significant lipid preference in homogeneous binary lipid mixtures in the fluid phase, even when using lipids that by themselves show very different solubilization kinetics. By contrast, in heterogeneous phase-separated bilayers, SMA was found to have a strong preference for solubilization of lipids in the fluid phase as compared to those in either a gel phase or a liquid-ordered phase. Together the results suggest that (1) SMA is a reliable tool to characterize native interactions between membrane constituents, (2) any solubilization preference of SMA is not due to properties of individual lipids but rather due to properties of the membrane or membrane domains in which these lipids reside and (3) exploiting SMA resistance rather than detergent resistance may be an attractive approach for the isolation of ordered domains from biological membranes.