Acid Polymer Research Articles

Ionizable cationic lipid nanoparticles loaded with miRNA-125b/BLZ945 for pancreatic cancer treatment.

In prior research, both miRNA-125b and BLZ945 have shown potential in effectively inhibiting M2 macrophage polarization and producing antitumor effects. Nevertheless, their physicochemical characteristics present significant challenges for efficient in vivo delivery. Ionizable cationic lipid nanoparticles (LNPs), recognized for their superior biocompatibility and drug-loading capacity, serve as a novel carrier for nucleic acid-based therapeutics. In our study, we successfully encapsulated both agents within LNPs and conducted a thorough characterization. Subsequently, we investigated their potential to repolarize M2 macrophages in vitro and evaluated their in vivo distribution, biosafety, and antitumor efficacy. The findings revealed that the LNPs maintained excellent drug-loading efficiency, consistent particle size, and stable zeta potential. All formulations effectively inhibited M2 macrophage polarization in vitro. Upon administration in vivo, the LNPs not only demonstrated favorable biosafety profiles but also accumulated efficiently in tumor tissues, substantially reducing tumor burden, particularly notable in co-loaded LNPs. Our results affirm that LNPs are an effective carrier for miRNA-125b and BLZ945, highlighting this encapsulation approach as promising for the treatment of solid tumors and meriting further investigation. Practitioner points: (i) Ionizable cationic nanoparticles provide high and stable encapsulation rates to efficiently load nucleic acid polymers into the LNP, avoiding the rapid accumulation of circulating macrophages, which can lead to reduced penetration of the LNP into target tissues. Therefore, it can be used as a novel drug delivery method to benefit clinical patients. (ii) miRNA-125b LNP/BLZ945 LNP attenuated the depleting effect of BLZ945 on macrophages and significantly inhibited macrophage M2 polarization. It could be effectively distributed in tumors and showed good biosafety while exerting antitumor effects, bringing hope to clinical pancreatic tumor patients.

Synthetic lignin derived from ferulic acid for UV-blocking sunscreen.

Conventional lignin, a dehydrogenated polymer derived primarily from hydroxycinnamic alcohol monomers, exhibits relatively low antioxidant and ultraviolet (UV)-blocking activities due to its structural imperfection. Herein, we demonstrated that the dehydrogenated polymer of ferulic acid (an unconventional lignin precursor) (FAL) had excellent antioxidant and UV-blocking properties. Structural characterization showed that FAL contains abundant dihydrobenzofuran and butyrolactone structures, free phenolic hydroxyl groups, and cinnamic acid end groups. Such structural characteristics endow FAL with much higher antioxidant activity and broader and stronger UV absorptivity (especially UVA) than conventional lignins. Our investigation showed that FAL could significantly improve the UV-blocking property of commercial SPF30 and SPF50 and render a relatively light color. These versatile properties make the FAL a potential ingredient for application in sunscreen products. This work is enlightening not only for exploring better antioxidant and UV-blocking polymers from the dehydrogenated polymers of phenolic compounds but also for biosynthesizing more advantageous lignin in plants.

A review of exploring the synthesis, properties, and diverse applications of poly lactic acid with a focus on food packaging application.

Polylactic acid (PLA) is an aliphatic polyester, which is primarily synthesized from renewable resources through the polycondensation or ring-opening polymerization of lactic acid (LA)/lactide. LA can be conveniently produced via the fermentation of sugars obtained from renewable sources such as corn and sugar cane. Due to its biodegradable and biocompatible nature, PLA exhibits a vast range of applications. Its advantages include non-toxicity, environmental safety, and compatibility with human biological systems. PLA finds significant use in various biomedical applications, including implants, tissue engineering, sutures, and drug delivery systems. Additionally, PLA serves as a renewable and biodegradable polymer of extensive utility in film production, offering an alternative to petrochemical-based polymers. Moreover, the properties of PLA-based films can be tailored by incorporating extracts, polysaccharides, proteins, and nano-particles. This review encompasses LA production, PLA synthesis, and diverse applications of PLA and further explores the potential of PLA in the realm of packaging.

A novel sustainable wood-based negative air anion generator utilizing in-situ polymerization of polylactic acid to reinforce the cellulose framework

The generation of negative air ions (NAI) by furniture contributes to indoor air purification and enhances the living environment. However, commercially available furniture typically relies on surface coatings to release NAI. Over time, the degradation of these coatings leads to a significant decline in NAI release performance, presenting a persistent challenge for sustained effectiveness. Here, a novel sustainable wood-based negative air anion generator (SWNG) had been developed, utilizing a cellulose framework as the substrate. The in-situ synthesis of polylactic acid (PLA) within the wood incorporated titanium dioxide (TiO2), tourmaline (TL), and cellulose acetate, firmly anchoring these materials within the wood structure. Compared to the cellulose framework alone, the NAI production of the SWNG had increased by 406.67 %. The impregnation with PLA enhanced the enduring photocatalytic activity of TiO2 and TL in this innovative wooden NAI generator. After undergoing 200 cycles of testing between −40 °C and 50 °C, it continued to sustain NAI production, demonstrating exceptional antibacterial performance. Overall, this study introduced a novel sustainable wood-based negative air ion generator as a highly stable material with sustainable properties, offering significant potential for applications in improving indoor air quality and in the domain of home construction.

Lignin-coated liquid metals-induced synthesis of deep eutectic solvent-based hydrogels with environmentally tolerant for strain sensors

In the work, alkali lignin (AL) was used as a coating layer for dispersing liquid metals (LM) in a ternary DES (choline chloride/ethylene glycol/water) system and generating free radical-catalyzed acrylic acid (AA) polymerization. The preparation of flexible sensors had high electrical conductivity (0.33 S·m-1), excellent self-healing and mechanical properties (84.7 KPa). The presence of AL facilitated the dispersion of LM in the DES system and the formation of a flexible hydrogel without the addition of an initiator. Moreover, DES was used as the liquid component of the PAA-AL2@LM2 hydrogel made it more environmentally tolerant and had better water retention. Even at -20 °C, the hydrogel exhibited low electrical resistance (131.4 Ω). The moisture loss of the prepared hydrogel was only 9% after 7 days at room temperature. This work exploited the significant advantages of DES and lignin-based materials in dispersing LM to provide a new technique for the preparation of metal-polymer composite hydrogels, which has great potential in the field of flexible sensors.

Enzymatic coloration for enhancing antibacterial features of silk: horseradish peroxidase-catalyzed polymerization of gallic acid with Chitosan

Enzymatic coloration for enhancing antibacterial features of silk: horseradish peroxidase-catalyzed polymerization of gallic acid with Chitosan

Assessment of the Recovery of Erythritol Using Boronic Acid Polymers

Assessment of the Recovery of Erythritol Using Boronic Acid Polymers

High-performance conductive double-network hydrogel base on sodium carboxymethyl cellulose for multifunctional wearable sensors

Sodium carboxymethyl cellulose showed great potential in wearable intelligent electronic devices due to its low price and good biocompatibility. This research aimed to develop a novel conductive hydrogel with stretchable, self-healing, self-adhesive, antibacterial, 3D printable properties, for the development of multifunctional flexible electronic materials based on sodium carboxymethyl cellulose. A multifunctional conductive hydrogel based on sodium carboxymethyl cellulose (SCMC) was synthesized by simple polymerization of SCMC, acrylic acid (AA) and alkaline calcium bentonite (AC-Bt). The multifunctional hydrogels (PAA-SCMC) possess excellent mechanical property (stress: 0.25 MPa; strain: 1675.0 %), Young's modulus (75.6 kPa), and conductivity (2.25 S/m). The multifunctional PAA-SCMC hydrogels serve as strain sensors (Gauge Factor (GF) = 12.68), temperature sensors (temperature coefficient of resistance (TCR) = −0.887 % °C at 20 °C–60 °C), sweat sensors, and pressure sensors. Importantly, the obtained hydrogels exhibited exceptional self-healing capability, self-adhesive properties, antimicrobial properties and 3D printability. The printed hydrogel has good mechanical properties, conductivity and antibacterial properties. Moreover, the hydrogel sensor possessed prominent sensitivity and cyclic stability to accurately monitor human motion, emotional changes, physiological signals in real time, and a hydrogel-based flexible touch keyboard was also fabricated to recognize writing trajectories. Overall, this study provided novel insights into the simple and efficient synthesis and sustainable manufacturing of environmentally friendly multifunctional flexible electronic skin sensors.

Acidic polymers reversibly deactivate phages due to pH changes.

Bacteriophages are promising as therapeutics and biotechnological tools, but they also present a problem for routine and commercial bacterial cultures, where contamination must be avoided. Poly(carboxylic acids) have been reported to inhibit phages' ability to infect their bacterial hosts and hence offer an exciting route to discover additives to prevent infection. Their mechanism and limitations have not been explored. Here, we report the role of pH in inactivating phages to determine if the polymers are unique or simply acidic. It is shown that lower pH (=3) triggered by either acidic polymers or similar changes in pH using HCl lead to inhibition. There is no inhibitory activity at higher pHs (in growth media). This was shown across a panel of phages and different molecular weights of commercial and controlled-radical polymerization-derived poly(acrylic acid)s. It is shown that poly(acrylic acid) leads to reversible deactivation of phage, but when the pH is adjusted using HCl alone the phage is irreversibly deactivated. Further experiments using metal binders ruled out ion depletion as the mode of action. These results show that polymeric phage inhibitors may work by unique mechanisms of action and that pH alone cannot explain the observed effects whilst also placing constraints on the practical utility of poly(acrylic acid).

Rapid preparation of bioadhesive hydrogels containing catechol moieties at room temperature with reproducible adhesion to wet tissues, antimicrobial, antioxidant capacity for noncompressive hemostasis

In order to cope with the massive tissue bleeding caused by sudden trauma and the demand for bioengineering materials with adjustable wet adhesion properties, this study formed the first layer of network by adding galactomannan (GG) and collagen (Col) structure, and then use the Fe3+-urushiol (UH) redox system to activate free radicals to initiate the polymerization of acrylic acid (AA) to quickly form an interpenetrating double network hydrogel. The cis hydroxyl group in GG and the hydroxyl group of UH form dynamic covalent borate ester bonds with borate ions in the borax solution, and use their responsiveness to pH to control the catechol group to achieve controllable adhesion. UH and Fe3+ endowed the hydrogel with excellent antibacterial ability, while adding Col enhanced the mechanical properties of the hydrogel. The elastic modulus and toughness increased from 4.32 kPa and 92.9 kJ/m3 to 18.90 kPa and 264.54 kJ/m3. In addition, due to the joint action of UH and Col, the hydrogel dressing can achieve rapid hemostasis within 20 s. In short, this hydrogel dressing has good biocompatibility, inherent antibacterial ability, adjustable moist tissue adhesion properties and rapid hemostatic ability, and is expected to become a candidate for wound hemostasis dressing.

Dynamic Analysis and Vibration Control of Additively Manufactured Thin-Walled Polylactic Acid Polymer (PLAP) and PLAP Composite Beam Structures: Numerical Investigation and Experimental Validation.

This study primarily presents a numerical investigation of the dynamic behavior and vibration control in thin-walled, additively manufactured (AM) beam structures, validated through experimental results. Vibration control in thin-walled structures has gained significant attention recently because vibrations can severely affect structural integrity. Therefore, it is necessary to minimize these vibrations or keep them within acceptable limits to ensure the structure's integrity. In this study, the AM beam structures were made of polylactic acid polymer (PLAP), short carbon fiber reinforced in PLAP (SCFR|PLAP), and continuous carbon fiber reinforced in PLAP (CCFR|PLAP), with 0°|0° layer orientations. The finite element modeling (FEM) of the AM beam structures integrated with macro fiber composite (MFC) was carried out in Abaqus. The initial four modal frequencies of bending modes (BMs) and their respective modal shapes were acquired through numerical simulation. It is crucial to highlight the numerical findings that reveal discrepancies in the 1st modal frequencies of the beams, ranging up to 1.5% compared to their respective experimental values. For the 2nd, 3rd, and 4th modal frequencies, the discrepancies are within 10%. Subsequently, frequency response analysis (FRA) was carried out to observe the frequency-dependent vibration amplitude spectrum at the initial four BM frequencies. Despite discrepancy in the amplitude values between the numerical and experimental datasets, there was consistency in the overall amplitude behavior as frequency varied. THz spectroscopy was performed to identify voids or misalignment errors in the actual beam models. Finally, vibration amplitude control using MFC (M8507-P2) was examined in each kinematically excited numerical beam structure. After applying a counterforce with the MFC, the controlled vibration amplitudes for the PLAP, SCFR|PLAP, and CCFR|PLAP configurations were approximately ±19 µm, ±16 µm, and ±13 µm, respectively. The trend in the controlled amplitudes observed in the numerical findings was consistent with the experimental results. The numerical findings of the study reveal valuable insights for estimating trends related to vibration control in AM beam structures.

A comparative analysis of PLA and PCL microparticles for hydrophilic and hydrophobic drugs

This study aims to investigate Polylactic Acid (PLA) and Polycaprolactone (PCL) polymers for microencapsulation of hydrophilic and hydrophobic anti-glaucoma drugs using an emulsion-based solvent evaporation technique. Microparticle size was analysed using optical microscopy, while drug-polymer interactions through Dynamic-Light-Scattering (DLS) and Fourier-Transform-Infra-red/Attenuated-Total-Reflection spectroscopy (FTIR/ATR). In vitro, drug release studies were performed to investigate drug encapsulation and release profiles. Spherical microparticles, with particle size 94 ± 6.9 μm for PCL-based and 100 ± 3.74 μm for PLA-based formulation, were obtained. Drug release studies showed 100% release over about 32 days, with encapsulation efficiency (%EE) and drug loading (%w/w) reaching up to 95 and 2.84% for PLA-based and 97 and 2.91% for PCL-based microparticles, respectively. DLS studies reveal an increase in hydrodynamic radius (RH ), which correlates to enhanced drug encapsulation. So, the nature of the drug and polymer significantly impacts drug encapsulation and release, with drug-polymer interactions playing a crucial role alongside experimental parameters.

Evaluation of polylactic acid polymer composites strengthened with chopped vetiver fiber and pearl millet-derived- nano silica towards environmental sustainability

Evaluation of polylactic acid polymer composites strengthened with chopped vetiver fiber and pearl millet-derived- nano silica towards environmental sustainability

Key Advances in Solution Blow Spinning of Polylactic-Acid-Based Materials: A Prospective Study on Uses and Future Applications.

Solution blow spinning (SBS) is a versatile and cost-effective technique for producing nanofibrous materials. It is based on the principles of other spinning methods as electrospinning (ES), which creates very thin and fine fibers with controlled morphologies. Polylactic acid (PLA), a biodegradable and biocompatible polymer derived from renewable resources, is widely used in biomedical fields, environmental protection, and packaging. This review provides a theoretical background for PLA, focusing on its properties that are associated with structural characteristics, such as crystallinity and thermal behavior. It also discusses various methods for producing fibrous materials, with particular emphasis on ES and SBS and on describing in more detail the main properties of the SBS method, along with its processing conditions and potential applications. Additionally, this review examines the properties of nanofibrous materials, particularly PLA-based nanofibers, and the new applications for which it is thought that they may be more useful, such as drug delivery systems, wound healing, tissue engineering, and food packaging. Ultimately, this review highlights the potential of the SBS method and PLA-based nanofibers in various new applications and suggests future research directions to address existing challenges and further enhance the SBS method and the quality of fibrous materials.

Light‐Assisted Polyproton Dissociated PAAm‐PA Hydrogel‐Based Moisture‐Driven Electricity Generator with a Broad Operating Range

AbstractDue to its widespread availability and spontaneity, moisture electricity generation (MEG) holds unique advantages in self‐powered systems. However, it faces challenges, including the limitations of relying on a single kind of power generation and insufficient output performance. Inspired by the mechanisms of water absorption of plants, this paper explores a light‐moisture coordinated electricity generating hydrogel (L‐MEGH) device with flexible, scalable, and highly efficient energy conversion performance, which is obtained through the UV polymerization of hydrophilic acrylamide (AAM) and phytic acid (PA) in the presence of photosensitizers. The obtained hydrogel demonstrates superior moisture absorption and remarkable electricity generation stability across a range of humidity conditions. Notably, the open‐circuit voltage (Voc) of the L‐MEGH increased from 0.675 to 0.838 V after the addition of photosensitizers (Erythrosin B, E) (the significant enhancement, up to 24%), and the short‐circuit current (Isc) reaching 635.543 µA. This L‐MEGH can realize stable electrical output even under extreme temperatures, producing 0.5 V at −20 °C for 45 h. The scalable L‐MEGHs (connected on‐demand in series/parallel) can power various commercial electronics, including nighttime illumination, mobile phones, and health monitoring sensors. This work pioneers a sustainable power generation pathway capable of enhancing performance through the hybrid collection of multiple natural energy sources.

Fluorescent Scandium Microspheres for Highly Efficient White‐Light Photocatalysis

AbstractEfficient photocatalysts play an important role in the various fields such as pollutant treatment and the generation of clean energy. Therefore, developing a photocatalyst with high activity is of great significance. Herein, scandium‐based fluorescent microspheres (Sc‐FMs) are facilely prepared through the one‐pot hydrothermal polymerization of scandium ions and tartaric acid. The prepared Sc‐FMs show strong blue solid‐state fluorescence, with a maximum emission at 412 nm. Meanwhile, Sc‐FMs possess a strong white‐light photocatalysis ability, which can be used for the photodegradation of dye pollutants (rhodamine 6 G) under low power white light without the assistance of any radical generating agents. In addition, the Sc‐FMs display good stability and recyclability. As a result, this new and efficient Sc‐FMs photocatalysts hold a promise for potential applications in environmental treatment.

Development of erythromycin loaded PLGA nanoparticles for improved drug efficacy and sustained release against bacterial infections and biofilm formation

Bacterial infections are a common cause of sepsis, often leading to high patient mortality. Such infections are challenging to treat due to bacterial resistance to many existing drugs. Erythromycin (Ery) is a macrolide antibiotic used against bacterial infections with reported resistance. Recently, synthetic poly-lactide co-glycolic acid (PLGA) polymer nanoparticles (NPs) have displayed improved drug delivery characteristics and biocompatibility. In this study, PLGA-Ery NPs were synthesized by the o/w emulsion diffusion method, having a particle size of 159 ± 23 nm and displayed 71.89 % of encapsulation efficiency. The PLGA-Ery NPs showed 1.5, 2.1 and 1.5-fold improved MIC and antibacterial efficacy against E. coli, S. aureus, and P. aeruginosa, respectively than the pure drug. As illustrated by scanning electron microscopy, PLGA-Ery NPs caused damage to the bacterial cell walls. Furthermore, a surface coating with PLGA-Ery NPs on a glass surface showed efficient inhibition (>90 %) of the biofilm formation by P. aeruginosa, as determined by fluorescence microscopy and MTT assay. This study demonstrates that PLGA-Ery NPs can increase the efficiency of erythromycin and can suppress the growth and biofilm formation of P. aeruginosa. Such polymeric nanoparticles drug nanoformulations have potential as an antimicrobial and as a surface coating for medical devices.

Formation, chemical evolution and solidification of the dense liquid phase of calcium (bi)carbonate.

Metal carbonates, which are ubiquitous in the near-surface mineral record, are a major product of biomineralizing organisms and serve as important targets for capturing anthropogenic CO2 emissions. However, pathways of carbonate mineralization typically diverge from classical predictions due to the involvement of disordered precursors, such as the dense liquid phase (DLP), yet little is known about DLP formation or solidification processes. Using in situ methods we report that a highly hydrated bicarbonate DLP forms via liquid-liquid phase separation and transforms into hollow hydrated amorphous CaCO3 particles. Acidic proteins and polymers extend DLP lifetimes while leaving the pathway and chemistry unchanged. Molecular simulations suggest that the DLP forms via direct condensation of solvated Ca²+⋅(HCO3-)2 complexes that react due to proximity effects in the confined DLP droplets. Our findings provide insight into CaCO3 nucleation that is mediated by liquid-liquid phase separation, advancing the ability to direct carbonate mineralization and elucidating an often-proposed complex pathway of biomineralization.

4D Printing: Research Focuses and Prospects

As an emerging technology in the field of additive manufacturing, 4D printing is highly disruptive to traditional manufacturing processes. Therefore, it is necessary to systematically summarize the research on 4D printing to promote the development of related industries and academic research. However, there is still an obvious gap in the visual connection between 4D printing theory and application research. We collected 2070 studies from 2013 on 4D printing from the core collection of Web of Science. We used VOSviewer 1.6.20 and CiteSpace software 6.3.3 to visualize the references and keywords to explore focuses and trends in 4D printing using scientometrics. In addition, real-world applications of 4D printing were analyzed based on the literature. The results showed that “tissue engineering applications” is the most prominent focus. In addition, “shape recovery”, “liquid crystal elastomer”, “future trends”, “bone tissue engineering”, “laser powder bed fusion”, “cervical spine”, “4D food printing”, “aesthetic planning” are also major focuses. From 2013 to 2015, focuses such as “shape memory polymers” and “composites” evolved into “fabrication”. From 2015 to 2018, the focus was on “technology” and “tissue engineering”. After 2018, “polylactic acid”, “cellulose”, and “regenerative medicine” became emerging focuses. Second, emerging focuses, such as polylactic acid and smart polymers, have begun to erupt and have become key research trends since 2022. “5D printing”, “stability” and “implants” may become emerging trends in the future. “4D + Food”, “4D + Cultural and Creative”, “4D + Life” and “4D + Clothing” may become future research trends. Third, 4D printing has been widely used in engineering manufacturing, biomedicine, food printing, cultural and creative life, and other fields. Strengthening basic research will greatly expand its applications in these fields and continuously increase the number of applicable fields.

Versatile Light-Mediated Synthesis of Degradable Bottlebrush Polymers Using α-Lipoic Acid.

Bottlebrush polymers have a variety of useful properties including a high entanglement molecular weight, low Young's modulus, and rapid kinetics for self-assembly. However, the translation of bottlebrushes to real-world applications is limited by complex, multi-step synthetic pathways and polymerization reactions that rely on air-sensitive catalysts. Additionally, most bottlebrushes are non-degradable. Herein, we report an inexpensive, versatile, and simple approach to synthesize degradable bottlebrush polymers under mild reaction conditions. Our approach relies on the "grafting-through" polymerization of α-lipoic acid (LA)-functionalized macromonomers. These macromonomers can be polymerized under mild, catalyst-free conditions, and due to reversibility of the disulfide bond in LA, the resulting bottlebrush polymers can be depolymerized by cleaving disulfide backbone bonds. Bottlebrushes with various side-chain chemistries can be prepared through the atom transfer radical polymerization (ATRP) of LA-functionalized macromonomers, and the backbone length is governed by the macromonomer molecular weight and solvent polarity. We also demonstrate that LA-functionalized macromonomers can be copolymerized with acrylates to form degradable bottlebrush networks. This work demonstrates the preparation of degradable bottlebrush polymers with a variety of side-chain chemistries and provides insight into the light-mediated grafting-through polymerization of dithiolane-functionalized macromonomers.