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The use of biopolymers as an alternative to petroleum-based polymers offers a sustainable solution with benefits such as biodegradability and unique functionalities. In this study, starch/zein bioparticles (BPs) obtained by nanoprecipitation were employed to synthesize acrylic polymer/biopolymer waterborne nanoparticles with excellent film formation capability. These hybrid nanoparticle dispersions were obtained through a semibatch emulsion polymerization using the previously synthesized BPs as seed and variable monomeric formulations composed of butyl acrylate and methyl methacrylate. A synergetic effect between acrylic and biopolymer phases was evidenced where the incorporation of BPs had a fundamental role in improving sensitive properties, such as film blocking resistance, while attaining smooth films at room temperature. These excellent film-forming properties of starch/acrylic hybrid latexes without requiring the addition of formulation agents, which depict an important benefit from an environmental viewpoint, demonstrate that they represent a promising alternative for the development of a new generation of eco-friendly binders.
Asunto(s)
Acrilatos , Nanopartículas , Almidón , Almidón/química , Nanopartículas/química , Acrilatos/química , Zeína/química , Polimerizacion , Agua/química , Resinas Acrílicas/químicaRESUMEN
Deep Eutectic Solvents (DES) are a new class of ionic conductive compounds attracting significant attention as greener alternatives to costly ionic liquids. Herein, we developed novel mixed ionic-electronic conducting materials by simple mixing of poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT:PSS) and various DES as additives. The DES addition induces the supramolecular assembly and gelification of PEDOT:PSS forming eutectogels triggered by extensive hydrogen bonding and charge stabilization. The eutectogels feature boosts the mixed ionic-electronic conductivity of PEDOT:PSS up to 368 S cm-1, unveiling great potential as flexible bioelectronics. All the PEDOT:PSS/DES gels showed shear-thinning behavior and viscosity values ranging from 100 to 1000 Pa s. The eutectogels show good injectability with almost instantaneous elastic recovery, making them ideal materials for direct ink writing (DIW). As proof of that, PEDOT:PSS/DES (choline chloride:lactic acid) was 3D printed in different patterns, annealed at high temperature, and assembled into adhesive electrodes. This way tattoos-like electrodes, denoted as Eutecta2 were fabricated and placed in vivo on the forearm and the thumb of human volunteers for electromyography measurements. Eutecta2 hexagonal patterns showed excellent conformability, and their signal-to-noise ratio (SNR) was higher than Ag/AgCl commercial electrodes for thumb motion measurements. Furthermore, forearm motion was measured after 14 days with similar values of SNR, demonstrating long-term stability and reusability. All in all, our findings revealed that DES could be used as inexpensive and safe additives to direct the self-assembly of PEDOT:PSS into supramolecular eutectogels inks for flexible bioelectronics.
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There is an actual need for developing materials for wound healing applications with anti-inflammatory, antioxidant, or antibacterial properties in order to improve the healing performance. In this work, we report the preparation and characterization of soft and bioactive iongel materials for patches, based on polymeric poly(vinyl alcohol) (PVA) and four ionic liquids containing the cholinium cation and different phenolic acid anions, namely cholinium salicylate ([Ch][Sal]), cholinium gallate ([Ch][Ga]), cholinium vanillate ([Ch][Van]), and cholinium caffeate ([Ch][Caff]). Within the iongels, the phenolic motif in the ionic liquids plays a dual role, acting as a PVA crosslinker and a bioactive compound. The obtained iongels are flexible, elastic, ionic conducting, and thermoreversible materials. Moreover, the iongels demonstrated high biocompatibility, non-hemolytic activity, and non-agglutination in mice blood, which are key-sought material specifications in wound healing applications. All the iongels have shown antibacterial properties, being PVA-[Ch][Sal], the one with higher inhibition halo for Escherichia Coli. The iongels also revealed high values of antioxidant activity due to the presence of the polyphenol, with the PVA-[Ch][Van] iongel having the highest activity. Finally, the iongels show a decrease in NO production in LPS-stimulated macrophages, with the PVA-[Ch][Sal] iongel displaying the best anti-inflammatory activity (>63% at 200 µg/mL).
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The design of ultratough hydrogels has recently emerged as a topic of great interest in the scientific community due to their ability to mimic the features of biological tissues. An outstanding strategy for preparing these materials relies on reversible and dynamic cross-links within the hydrogel matrix. In this work, inspired by the composition of ascidians' tunic, stretchable supramolecular hydrogels combining poly(vinyl alcohol), green tea-derived gallic acid, and rigid tannic acid-coated cellulose nanocrystals (TA@CNC) were designed. The addition of TA@CNC nanofillers in concentrations up to 1.2 wt % significantly impacted the mechanical and viscoelastic properties of the hydrogels due to the promotion of hydrogen bonding with the polymer matrix and polyphenols π-π stacking interactions. These supramolecular associations endow the hydrogels with excellent stretchability and strength (>340%, 540 kPa), low thermoreversible gel-sol transition (60 °C), and remolding ability, while the natural polyphenols provided potential antibacterial properties. These versatile materials can be anticipated to open up new prospects for the rational design of polyphenol-based cellulosic hydrogels for different biomedical applications.
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Nanocompuestos , Urocordados , Animales , Celulosa/farmacología , Celulosa/química , Nanogeles , Hidrogeles/farmacología , Hidrogeles/química , Antibacterianos/farmacologíaRESUMEN
Natural deep eutectics solvents (NADES), owing to their high solvation capacity and nontoxicity, are actively being sought for many technological applications. Herein, we report a series of novel NADES based on choline chloride and plant-derived polyphenols. Most of the obtained phenolic NADES have a wide liquid range and high thermal stability above 150 °C. Among them, small-sized polyphenols, like pyrogallol, vanillyl alcohol, or gentisic acid, lead to low-viscosity liquids with ionic conductivities in the order of 10-3 S cm-1 at room temperature. Interestingly, polyphenols possess valuable properties as therapeutic agents, antioxidants, adhesives, or redox-active compounds, among others. Thus, we evaluated the potential of these novel NADES for two applications: bioadhesives and corrosion protection. The mixture of choline chloride-vanillyl alcohol (2:3 mol ratio) and gelatin resulted in a highly adhesive viscoelastic liquid (adhesive stress ≈ 135 kPa), affording shear thinning behavior. Furthermore, choline chloride-tannic acid (20:1) showed an extraordinary ability to coordinate iron ions, reaching excellent corrosion inhibitive efficiencies in mild steel protection.
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Iongels are soft ionic conducting materials, usually composed of polymer networks swollen with ionic liquids (ILs), which are being investigated for applications ranging from energy to bioelectronics. The employment of iongels in bioelectronic devices such as bioelectrodes or body sensors has been limited by the lack of biocompatibility of the ILs and/or polymer matrices. In this work, we present iongels prepared from solely biocompatible materials: (i) a biobased polymer network containing tannic acid as a cross-linker in a gelatin matrix and (ii) three different biocompatible cholinium carboxylate ionic liquids. The resulting iongels are flexible and elastic with Young's modulus between 11.3 and 28.9 kPa. The morphology of the iongels is based on a dual polymer network system formed by both chemical bonding due to the reaction of the gelatin's amines with the polyphenol units and physical interactions between the tannic acid and the gelatin. These biocompatible iongels presented high ionic conductivity values, from 0.003 and up to 0.015 S·cm-1 at room temperature. Furthermore, they showed excellent performance as a conducting gel in electrodes for electromyography and electrocardiogram recording as well as muscle stimulation.
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Gelatina , Líquidos Iónicos , Electrodos , Gelatina/farmacología , Músculos , Polímeros , Taninos/farmacologíaRESUMEN
After several decades of development in the field of near-infrared (NIR) dyes for photothermal therapy (PTT), indocyanine green (ICG) still remains the only FDA-approved NIR contrast agent. However, upon NIR light irradiation ICG can react with molecular oxygen to form reactive oxygen species and degrade the ICG core, losing the convenient dye properties. In this work, we introduce a new approach for expanding the application of ICG in nanotheranostics, which relies on the confinement of self-organized J-type aggregates in hydrophobic protein domains acting as monomer depots. Upon the fast photobleaching, while the dye is irradiated, this strategy permits the equilibrium-driven monomer replacement after each irradiation cycle that radically increases the systems' effectivity and applicability. Gadolinium-doped casein micelles were designed to prove this novel concept at the same time as endowing the nanosystems with further magnetic resonance imaging (MRI) ability for dual-modal imaging-guided PTT. By teaching a new trick to a very old dog, the clinical prospect of ICG will undoubtedly be boosted laying the foundation for novel therapeutics. It is anticipated that future research could be expanded to other relevant J-aggregates-forming cyanine dyes or nanocrystal formulations of poorly water-soluble photosensitizers.
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Colorantes , Nanopartículas , Verde de Indocianina , Fototerapia , Nanomedicina TeranósticaRESUMEN
Iongels have attracted much attention over the years as ion-conducting soft materials for applications in several technologies including stimuli-responsive drug release and flexible (bio)electronics. Nowadays, iongels with additional functionalities such as electronic conductivity, self-healing, thermo-responsiveness, or biocompatibility are actively being searched for high demanding applications. In this work, a simple and rapid synthetic pathway to prepare elastic and thermoreversible iongels is presented. These iongels are prepared by supramolecular crosslinking between polyphenols biomolecules with a hydroxyl-rich biocompatible polymer such as poly(vinyl alcohol) (PVA) in the presence of ionic liquids. Using this strategy, a variety of iongels are obtained by combining different plant-derived polyphenol compounds (PhC) such as gallic acid, pyrogallol, and tannic acid with imidazolium-based ionic liquids, namely 1-ethyl-3-methylimidazolium dicyanamide and 1-ethyl-3-methylimidazolium bromide. A suite of characterization tools is used to study the structural, morphological, mechanical, rheological, and thermal properties of the supramolecular iongels. These iongels can withstand large deformations (40% under compression) with full recovery, revealing reversible transitions from solid to liquid state between 87 and 125 °C. Finally, the polyphenol-based thermoreversible iongels show appropriated properties for their potential application as printable electrolytes for bioelectronics.
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Elasticidad , Geles/química , Fenol/química , Alcohol Polivinílico/química , Temperatura , Rastreo Diferencial de Calorimetría , Fuerza Compresiva , Ácido Gálico/química , Iones , Polifenoles/química , Espectroscopía Infrarroja por Transformada de Fourier , TermogravimetríaRESUMEN
In this work, we report the synthesis of graft copolymers based on casein and N-isopropylacrylamide, which can self-assemble into biodegradable micelles of approximately 80 nm at physiological conditions. The obtained copolymers were degraded by trypsin, an enzyme that is overexpressed in several malignant tumors. Moreover, graft copolymers were able to load doxorubicin (Dox) by ionic interaction with the casein component. In vitro release experiments showed that the in situ assembled micelles can maintain the cargo at plasma conditions but release Dox immediately after their exposition at pH 5.0 and trypsin. Cellular uptake and cytotoxicity assays revealed the efficient delivery to the nucleus and antiproliferative efficacy of Dox in the breast cancer cell line MDA231. Both delivery and therapeutic activity were enhanced in presence of trypsin. Overall, the prepared micelles hold a great potential for their utilization as dual responsive trypsin/pH drug delivery system.
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Acrilamidas/química , Antineoplásicos/química , Caseínas/química , Doxorrubicina/química , Portadores de Fármacos/química , Polímeros/química , Temperatura , Antineoplásicos/farmacología , Transporte Biológico , Línea Celular Tumoral , Portadores de Fármacos/metabolismo , Humanos , Concentración de Iones de Hidrógeno , Polímeros/metabolismoRESUMEN
Supramolecular hydrogels have promising applications in a wide variety of fields including 3D bioprinting, sensors and actuators, biomedicine, and controlled drug delivery. This communication reports the facile reversible thermotriggered formation of novel pH-responsive supramolecular hydrogels based on poly(vinyl alcohol) (PVA) bonded via dynamic H-bridge with small phenolic biomolecules. PVA and phenolic compounds form a clear solution when they are physically mixed in water at high temperature, but a fast gelation is produced at room temperature through multiple strong H-bonding interactions. The structure and type of functional groups of different phenolic molecules allow preparing hydrogels with tailor-made viscoelastic properties, controlled low phase transition temperature, and pH-dependent swelling behavior. This combination makes these supramolecular networks very interesting candidates to be used in 3D bioprinting and topical drug delivery of thermolabile biomolecules.
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Hidrogeles/química , Fenoles/química , Alcohol Polivinílico/química , Sistemas de Liberación de Medicamentos/métodos , Hidrogeles/síntesis química , Enlace de Hidrógeno , Transición de Fase , Temperatura , Sustancias Viscoelásticas/químicaRESUMEN
Transdermal immunization is highly attractive because of the skin's accessibility and unique immunological characteristics. However, it remains a relatively unexplored route of administration because of the great difficulty of transporting antigens past the outermost layer of skin, the stratum corneum. In this article, the abilities of three poly( N-vinylcaprolactam) (PVCL)-based thermoresponsive assemblies-PVCL hydrogels and nanogels plus novel film forming PVCL/acrylic nanogels-to act as protein delivery systems were investigated. Similar thermal responses were observed in all systems, with transition temperatures close to 32 °C, close to that of the skin surface. The investigated dermal delivery systems showed no evidence of cytotoxicity in human fibroblasts and were able to load and release ovalbumin (OVA), a well-studied antigen, in a temperature-dependent manner in vitro. The penetration of OVA into ex vivo human skin following topical application was evaluated, where enhanced skin delivery was seen for the OVA-loaded PVCL systems relative to administration of the protein alone. The distinct protein release and skin penetration profiles observed for the different PVCL assemblies were here discussed on the basis of their structural differences.