Polyester urethane urea (PEUU) functionalization for enhanced anti-thrombotic performance: advancing regenerative cardiovascular devices through innovative surface modifications

Introduction: Thrombogenesis, a major cause of implantable cardiovascular device failure, can be addressed through the use of biodegradable polymers modified with anticoagulating moieties. This study introduces a novel polyester urethane urea (PEUU) functionalized with various anti-platelet deposition molecules for enhanced antiplatelet performance in regenerative cardiovascular devices. Methods: PEUU, synthesized from poly-caprolactone, 1,4-diisocyanatobutane, and putrescine, was chemically oxidized to introduce carboxyl groups, creating PEUU-COOH. This polymer was functionalized in situ with polyethyleneimine, 4-arm polyethylene glycol, seleno-L-cystine, heparin sodium, and fondaparinux. Functionalization was confirmed using Fourier-transformed infrared spectroscopy and X-ray photoelectron spectroscopy. Bio-compatibility and hemocompatibility were validated through metabolic activity and hemolysis assays. The anti-thrombotic activity was assessed using platelet aggregation, lactate dehydrogenase activation assays, and scanning electron microscopy surface imaging. The whole-blood clotting time quantification assay was employed to evaluate anticoagulation properties. Results: Results demonstrated high biocompatibility and hemocompatibility, with the most potent anti-thrombotic activity observed on pegylated surfaces. However, seleno-L-cystine and fondaparinux exhibited no anti-platelet activity. Discussion: The findings highlight the importance of balancing various factors and addressing challenges associated with different approaches when developing innovative surface modifications for cardiovascular devices.

Unlocking cellular barriers: silica nanoparticles and fullerenol conjugated cell-penetrating agents for enhanced intracellular drug delivery

The limited delivery of cargoes at the cellular level is a significant challenge for therapeutic strategies due to the presence of numerous biological barriers. By immobilizing the Buforin II (BUF-II) peptide and the OmpA protein on magnetite nanoparticles, a new family of cell-penetrating nanobioconjugates was developed in a previous study. We propose in this study to extend this strategy to silica nanoparticles (SNPs) and silanized fullerenol (F) as nanostructured supports for conjugating these potent cell-penetrating agents. The same molecule conjugated to distinct nanomaterials may interact with subcellular compartments differently. On the obtained nanobioconjugates (OmpA-SNPs, BUF-II-PEG₁₂-SNPs, OmpA-F, and BUF-II-PEG₁₂-F), physicochemical characterization was performed to evaluate their properties and confirm the conjugation of these translocating agents on the nanomaterials. The biocompatibility, toxicity, and internalization capacity of nanobioconjugates in Vero cells and THP-1 cells were evaluated in vitro. Nanobioconjugates had a high internalization capacity in these cells without affecting their viability, according to the findings. In addition, the nanobioconjugates exhibited negligible hemolytic activity and a low tendency to induce platelet aggregation. In addition, the nanobioconjugates exhibited distinct intracellular trafficking and endosomal escape behavior in these cell lines, indicating their potential for addressing the challenges of cytoplasmic drug delivery and the development of therapeutics for the treatment of lysosomal storage diseases. This study presents an innovative strategy for conjugating cell-penetrating agents using silica nanoparticles and silanized fullerenol as nanostructured supports, which has the potential to enhance the efficacy of cellular drug delivery.

Novel Photo- and Thermo-Responsive Nanocomposite Hydrogels Based on Functionalized rGO and Modified SIS/Chitosan Polymers for Localized Treatment of Malignant Cutaneous Melanoma

Melanoma is an aggressive type of skin cancer that accounts for over 75% of skin cancer deaths despite comprising less than 5% of all skin cancers. Despite promising improvements in surgical approaches for melanoma resection, the survival of undetectable microtumor residues has remained a concern. As a result, hyperthermia- and drug-based therapies have grown as attractive techniques to target and treat cancer. In this work, we aim to develop a stimuli-responsive hydrogel based on chitosan methacrylate (ChiMA), porcine small intestine submucosa methacrylate (SISMA), and doxorubicin-functionalized reduced graphene oxide (rGO-DOX) that eliminates microtumor residues from surgically resected melanoma through the coupled effect of NIR light-induced photothermal therapy and heat-induced doxorubicin release. Furthermore, we developed an in silico model to optimize heat and mass transport and evaluate the proposed chemo/photothermal therapy in vitro over melanoma cell cultures.

Preparation and Characterization of an Injectable and Photo-Responsive Chitosan Methacrylate/Graphene Oxide Hydrogel: Potential Applications in Bone Tissue Adhesion and Repair

As life expectancy continues to increase, the inevitable weakening and rupture of bone tissue have grown as concerns in the medical community, thus leading to the need for adhesive materials suitable for bone repair applications. However, current commercially available adhesives face certain drawbacks that prevent proper tissue repair, such as low biocompatibility, poor adhesion to wet surfaces, and the need for high polymerization temperatures. This work aims to develop an injectable and photo-responsive chitosan methacrylate/graphene oxide (ChiMA/GO) adhesive nanocomposite hydrogel of high biocompatibility that is easy to apply by simple extrusion and that offers the possibility for in situ polymer and physiological temperatures. The nanocomposite was thoroughly characterized spectroscopically, microscopically, rheologically, thermally, and through mechanical, textural, and biological assays to fully evaluate its correct synthesis and functionalization and its performance under physiological conditions that mimic those observed in vivo. In addition, a finite element analysis (FEA) simulation was used to evaluate its performance in femur fractures. Results suggest the material’s potential as a bioadhesive, as it can polymerize at room temperature, shows superior stability in physiological media, and is capable of withstanding loads from body weight and movement. Moreover, the material showed remarkable biocompatibility as evidenced by low hemolytic and intermediate platelet aggregation tendencies, and high cytocompatibility when in contact with osteoblasts. The comprehensive studies presented here strongly suggest that the developed hydrogels are promising alternatives to conventional bone adhesives that might be further tested in vivo in the near future.

Ru0·Ru n+/Al2O3 as a Versatile Catalyst in the Isomerization of Allyl Alcohol

This study focuses on examining the isomerization of allyl alcohol using ruthenium (Ru) supported on alumina as a heterogeneous catalyst. The synthesized Ru/Al solids were characterized by various characterization techniques. The content of Ru was estimated by the energy dispersive x-ray technique. The x-ray diffraction (XRD) confirmed the presence of phases in the support and active species in the catalysts. The surface area of the support after Ru impregnation and the pore volume were determined by nitrogen physisorption. The analysis of programmed temperature (TPR and TPO) shows different redox sites which is confirmed by XPS. The catalytic results suggest a dependence on the amount of available metallic Ru, as well as the importance of the continuous regeneration of the metal using H2 to achieve a good conversion of the allyl alcohol. For comparison purposes, the commercial Ru on alumina 5% (CAS 908142) was used. The results show up to 68% alcohol conversion and 27% yield of the isomerization product using Ru(1,5.4h)/Al catalyst in comparison with 86% conversion and 39% yield of the isomerization product using CAS 908142. In contrast, our catalysts always presented higher TOF values (149-160) in comparison with CAS 908142 (101).

Antidelaminating, Thermally Stable, and Cost-Effective Flexible Kapton Platforms for Nitrate Sensors, Mercury Aptasensors, Protein Sensors, and p-Type Organic Thin-Film Transistors

The inkjet printing of metal electrodes on polymer films is a desirable manufacturing process due to its simplicity but is limited by the lack of thermal stability and serious delaminating flaws in various aqueous and organic solutions. Kapton, adopted worldwide due to its superior thermal durability, allows the high-temperature sintering of nanoparticle-based metal inks. By carefully selecting inks (Ag and Au) and Kapton substrates (Kapton HN films with a thickness of 135 μm and a thermal resistance of up to 400 °C) with optimal printing parameters and simplified post-treatments (sintering), outstanding film integrity, thermal stability, and antidelaminating features were obtained in both aqueous and organic solutions without any pretreatment strategy (surface modification). These films were applied in four novel devices: a solid-state ion-selective (IS) nitrate (NO₃^-) sensor, a single-stranded DNA (ssDNA)-based mercury (Hg²⁺) aptasensor, a low-cost protein printed circuit board (PCB) sensor, and a long-lasting organic thin-film transistor (OTFT). The IS NO₃^- sensor displayed a linear sensitivity range between 10^-4.5 and 10^-1 M (r² = 0.9912), with a limit of detection of 2 ppm for NO₃^-. The Hg²⁺ sensor exhibited a linear correlation (r² = 0.8806) between the change in the transfer resistance (R_CT) and the increasing concentration of Hg²⁺. The protein PCB sensor provided a label-free method for protein detection. Finally, the OTFT demonstrated stable performance, with mobility values in the linear (μ_lin) and saturation (μ_sat) regimes of 0.0083 ± 0.0026 and 0.0237 ± 0.0079 cm² V^-1 S^-1, respectively, and a threshold voltage (V_th) of -6.75 ± 3.89 V.

Multifunctional magnetite nanoparticles to enable delivery of siRNA for the potential treatment of Alzheimer's

Therapeutic drugs for Alzheimer's disease have been extensively studied due to its recurrence and abundance among neurodegenerative diseases. It is thought that the accumulation of amyloid precursor protein (APP) products, a consequence of an up-regulation of the β-site APP-cleaving enzyme 1 (BACE1), is the main triggering mechanism during the early stages of the disease. This study aims to explore the ability of a multifunctional conjugate based on magnetite nanoparticles for the cellular delivery of siRNA against the expression of the BACE1 gene. We immobilized the siRNA strand on PEGylated magnetite nanoparticles and investigated the effects on biocompatibility and efficacy of the conjugation. Similarly, we co-immobilized the translocating protein OmpA on PEGylated nanoparticles to enhance cellular uptake and endosomal escape. BACE1 suppression was statistically significant in HFF-1 cells, without any presence of a cytotoxic effect. The delivery of the nanoconjugate was achieved through endocytosis pathways, where endosome formation was likely escaped due to the proton-sponge effect characteristic of PEGylated nanoparticles or mainly by direct translocation in the case of OmpA/PEGylated nanoparticles.

Inkjet Printed Nanopatterned Aptamer-Based Sensors for Improved Optical Detection of Foodborne Pathogens

The increasing incidence of infectious outbreaks from contaminated food and water supply continues imposing a global burden for food safety, creating a market demand for on-site, disposable, easy-to-use, and cost-efficient devices. Despite of the rapid growth of biosensors field and the generation of breakthrough technologies, more than 80% of the platforms developed at lab-scale never will get to meet the market. This work aims to provide a cost-efficient, reliable, and repeatable approach for the detection of foodborne pathogens in real samples. For the first time an optimized inkjet printing platform is proposed taking advantage of a carefully controlled nanopatterning of novel carboxyl-functionalized aptameric ink on a nitrocellulose substrate for the highly efficient detection of E. coli O157:H7 (25 colony forming units (CFU) mL^-1 in pure culture and 233 CFU mL^-1 in ground beef) demonstrating the ability to control the variation within ±1 SD for at least 75% of the data collected even at very low concentrations. From the best of the knowledge this work reports the lowest limit of detection of the state of the art for paper-based optical detection of E. coli O157:H7, with enough evidence (p > 0.05) to prove its high specificity at genus, species, strain, and serotype level.

Efficient cephalexin degradation using active chlorine produced on ruthenium and iridium oxide anodes: Role of bath composition, analysis of degradation pathways and degradation extent

The elimination of cephalexin (CPX) using electro-generated Cl₂-active on Ti/RuO₂-IrO₂ anode was assessed in different effluents: deionized water (DW), municipal wastewater (MWW) and urine. Single Ti/RuO₂ and Ti/IrO₂ catalysts were prepared to compare their morphologies and electrochemical behavior against the binary DSA. XRD and profile refinement suggest that Ti/RuO₂-IrO₂ forms a solid solution, where RuO₂ and IrO₂ growths are oriented by the TiO₂ substrate through substitution of Ir by Ru atoms within its rutile-type structure. SEM reveals mud-cracked structures with flat areas for all catalysts, while EDS analysis indicates atomic ratios in the range of the oxide stoichiometries in the nominal concentrations used during synthesis. A considerably higher CPX degradation is achieved in the presence of NaCl than in Na₂SO₄ or Na₃PO₄ media due to the active chlorine generation. A faster CPX degradation is reached when the current density is increased or the pH value is lowered. This last behavior may be ascribed to an acid-catalyzed reaction between HClO and CPX. Degradation rates of 22.5, 3.96, and 0.576 μmol L^-1 min^-1 were observed for DW, MWW and urine, respectively. The lower efficiency measured in these last two effluents was related to the presence of organic matter and urea in the matrix. A degradation pathway is proposed based on HPLC-DAD and HPLC-MS analysis, indicating the fast formation (5 min) of CPX-(S)-sulfoxide and CPX-(R)-sulfoxide, generated due the Cl₂-active attack at the CPX thioether. Furthermore, antimicrobial activity elimination of the treated solution is reached once CPX, and the initial by-products are considerably eliminated. Finally, even if only 16% of initial TOC is removed, BOD₅ tests prove the ability of electro-generated Cl₂-active to transform the antibiotic into biodegradable compounds. A similar strategy can be used for the abatement of other recalcitrant compounds contained in real water matrices such as urine and municipal wastewaters.