by Keyword: Crosslinking

Hamelmann NM, Paats JD, Avalos-Padilla Y, Lantero E, Spanos L, Siden-Kiamos I, Fernàndez-Busquets X, Paulusse JMJ, (2023). Single-Chain Polymer Nanoparticles Targeting the Ookinete Stage of Malaria Parasites Acs Infectious Diseases 9, 56-64

Malaria is an infectious disease transmitted by mosquitos, whose control is hampered by drug resistance evolution in the causing agent, protist parasites of the genus Plasmodium, as well as by the resistance of the mosquito to insecticides. New approaches to fight this disease are, therefore, needed. Research into targeted drug delivery is expanding as this strategy increases treatment efficacies. Alternatively, targeting the parasite in humans, here we use single-chain polymer nanoparticles (SCNPs) to target the parasite at the ookinete stage, which is one of the stages in the mosquito. This nanocarrier system provides uniquely sized and monodispersed particles of 5-20 nm, via thiol-Michael addition. The conjugation of succinic anhydride to the SCNP surface provides negative surface charges that have been shown to increase the targeting ability of SCNPs to Plasmodium berghei ookinetes. The biodistribution of SCNPs in mosquitos was studied, showing the presence of SCNPs in mosquito midguts. The presented results demonstrate the potential of anionic SCNPs for the targeting of malaria parasites in mosquitos and may lead to progress in the fight against malaria.

JTD Keywords: antimalarial, atovaquone, carriers, delivery, drug-conjugate, heparin, intramolecular crosslinking, plasmodium berghei, therapy, thiol-michael addition, transmission, Atovaquone, Drug-conjugate, Intramolecular crosslinking, Plasmodium berghei, Plasmodium-falciparum, Single chain polymer nanoparticles, Thiol-michael addition

Yazıcı N, Opar E, Kodal M, Tanören B, Sezen M, Özkoç G, (2022). A novel practical approach for monitoring the crosslink density of an ethylene propylene diene monomer compound: Complementary scanning acoustic microscopy and FIB-SEM-EDS analyses Polymers & Polymer Composites 30, 9673911221074192

Tuning of the crosslink density (CLD) in the rubber compounds is very crucial for optimizing the physical and mechanical properties of the ultimate rubber products. Conventionally, CLD can be measured via rheological methods such as moving die rheometer (MDR), via mechanical tests such as temperature scanning stress relaxation analysis (TSSR), or via direct swelling experiments using Flory–Rehner approach. In the current study, two novel techniques, focused ion beam - scanning electron microscopy (FIB-SEM) processing, with simultaneous energy dispersive X-ray spectrometry (EDS) mapping analysis and scanning acoustic microscopy (SAM) were combined and correlated to conventional methods on a model recipe of ethylene propylene diene monomer (EPDM) compound having different sulphur contents. Depending on the applied technique, the increase in the crosslink density with sulphur content was found to be 1.7 fold for the Flory–Rehner approach and 1.2 fold for both TSSR and MDR. It is directly monitored from the FIB-SEM-EDS analysis that the sulphur distribution and agglomeration behavior increased in line with ZnO content, which is an indirect indication of the rise in crosslink density. The impedance maps of the crosslinked samples obtained through SAM analysis revealed that the impedance of the samples increased with the increasing sulphur content, which can be attributed to higher level of crosslink density. A quantified correlation was obtained between SAM images and the crosslink density of the samples. It was shown that SAM is a promising tool for practical and non-destructive analysis for determining the formation of crosslink density of the rubbers. © The Author(s) 2022.

JTD Keywords: blends, compressibility, crosslink density, cure characteristics, ethylene propylene diene monomer, focused ion beam, mechanical-properties, morphology, natural-rubber, particles, scanning acoustic microscopy, scanning electron microscopy, sulfur, thermal-stability, vulcanization, Composite soft materials, Cross-link densities, Crosslink density, Crosslinking, Density (specific gravity), Ethylene, Ethylene propylene diene monomer, Flory-rehner, Focused ion beam - scanning electron microscopy, Focused ion beam-scanning electron microscopies, Ii-vi semiconductors, Monomers, Moving die rheometers, Physical and mechanical properties, Propylene, Relaxation analysis, Rubber, Scanning acoustic microscopy, Scanning electron microscopy, Stress relaxation, Sulfur contents, Temperature scanning stress relaxations, Zinc oxide

Rosales-Rojas, R, Zuniga-Bustos, M, Salas-Sepulveda, F, Galaz-Araya, C, Zamora, RA, Poblete, H, (2022). Self-Organization Dynamics of Collagen-like Peptides Crosslinking Is Driven by Rose-Bengal-Mediated Electrostatic Bridges Pharmaceutics 14, 1148

The present work focuses on the computational study of the structural micro-organization of hydrogels based on collagen-like peptides (CLPs) in complex with Rose Bengal (RB). In previous studies, these hydrogels computationally and experimentally demonstrated that when RB was activated by green light, it could generate forms of stable crosslinked structures capable of regenerating biological tissues such as the skin and cornea. Here, we focus on the structural and atomic interactions of two collagen-like peptides (collagen-like peptide I (CLPI), and collagen-like peptide II, (CLPII)) in the presence and absence of RB, highlighting the acquired three-dimensional organization and going deep into the stabilization effect caused by the dye. Our results suggest that the dye could generate a ternary ground-state complex between collagen-like peptide fibers, specifically with positively charged amino acids (Lys in CLPI and Arg in CLPII), thus stabilizing ordered three-dimensional structures. The discoveries generated in this study provide the structural and atomic bases for the subsequent rational development of new synthetic peptides with improved characteristics for applications in the regeneration of biological tissues during photochemical tissue bonding therapies.

JTD Keywords: Anastomosis, Collagen-like peptide, Crosslinking, Green light, Mm simulations, Molecular dynamics, Molecular-dynamics, Photochemical tissue bonding therapies, Qm, Rose bengal

Ruano, G., Díaz, A., Tononi, J., Torras, J., Puiggalí, J., Alemán, C., (2020). Biohydrogel from unsaturated polyesteramide: Synthesis, properties and utilization as electrolytic medium for electrochemical supercapacitors Polymer Testing 82, 106300

The utilization of hydrogels derived from biopolymers as solid electrolyte (SE) of electrochemical supercapacitors (ESCs) is a topic of increasing interest because of their promising applications in biomedicine (e.g. for energy storage in autonomous implantable devices). In this work an unsaturated polyesteramide that contains phenylalanine, butenediol and fumarate as building blocks has been photo-crosslinked to obtain a hydrogel (UPEA-h). The structure of UPEA-h, which is characterized by a network of open interconnected pores surrounded by regions with compact morphology, favors ion transport, while the biodegradability and biocompatibility conferred by the α-amino acid unit and the ester group are appropriated for its usage in the biomedical field. Voltammetric and galvanostatic assays have been conducted to evaluate the behavior of UPEA-h when used as SE in ESCs with poly(3,4-ethylenedioxythiophene) (PEDOT) electrodes. Hence, PEDOT/UPEA-h devices displayed supercapacitor response of up 179 F/g and capacitance retention higher than 90%. Moreover, the long-term stability, leakage-current, and self-discharging response of PEDOT/UPEA-h ESCs reflect the great potential of UPEA-h as ion-conductive electrolyte. Indeed, the performance of PEDOT/UPEA-h is higher than found in analogous devices constructed using other biohydrogels as SE (e.g. κ-carrageenan, poly-γ-glutamic acid and cellulose hydrogels).

JTD Keywords: Energy storage, Hydrogel electronics, Ion conductivity, Photo-crosslinking, Wearable electronics

Hamouda, I., Labay, C., Ginebra, M. P., Nicol, E., Canal, C., (2020). Investigating the atmospheric pressure plasma jet modification of a photo-crosslinkable hydrogel Polymer 192, 122308

Atmospheric pressure plasma jets (APPJ) have great potential in wound healing, bacterial disinfection and in cancer therapy. Recent studies pointed out that hydrogels can be used as screens during APPJ treatment, or even be used as reservoirs for reactive oxygen and nitrogen species generated by APPJ in liquids. Thus, novel applications are emerging for hydrogels which deserve fundamental exploration of the possible modifications undergone by the polymers in solution due to the reactivity with plasmas. Here we investigate the possible modifications occurred by APPJ treatment of an amphiphilic poly(ethylene oxide)-based triblock copolymer (tPEO) photo-crosslinkable hydrogel. While APPJ treatments lead to a certain degradation of the self-assembly of the polymeric chains at low concentrations (<2 g/L), at the higher concentrations required to form a hydrogel (>2 g/L), the polymeric chains are unaffected by APPJ and the hydrogel forming ability is kept. APPJ treatments induced a pre-crosslinking of the network with an increase of the mechanical properties of the hydrogel. Overall, the small modifications induced allow thinking of polymer solutions with hydrogel forming ability a new platform for several applications related to plasma medicine, and thus, with potential in different therapies.

JTD Keywords: Atmospheric pressure plasma jet, Hydrogel, Photo-crosslinking, Polymer solution, Self-assembly