Maria Angeliki Ntrivala

In this study, Paliperidone Palmitate (PP), a second-generation antipsychotic, commonly used for the treatment of schizophrenia, was encapsulated in bio-based non-isocyanate polyurethane (NIPU) nanoemulsions. NIPU was synthesized via an isocyanate-free polyaddition route, addressing safety and environmental concerns associated with conventional polyurethanes. The drug-loaded nanoparticles were produced utilizing oil-in-water (O/W) emulsions followed by solvent evaporation and lyophilization. NIPU concentrations of 0.3% and 0.5% w/v, as well as 0.5% w/v PVA were employed, while PP was incorporated at 0.2%, 0.5% and 1% w/v. The formulations were characterized by FTIR, DSC and XRD analyses, and the mechanical strength of neat sponges was evaluated. The nanoparticle formation and size were assessed by DLS and SEM analyses. The water contact angle, porosity measurements and aquatic and enzymatic hydrolysis were additionally performed. The resulting nanocarriers exhibited controlled particle size, increased drug-loading values, structural stability and biodegradability. Lastly, the in vitro dissolution studies revealed a system-specific burst release behavior, and a controlled and sustained overall drug-release profile for majority of the formulations, thereby indicating the potential of NIPU nanocarriers for drug delivery applications, particularly where sustained therapeutic effects are required.

Printed electronics (PE) have emerged as a rapidly growing technology owing to their potential for low-cost fabrication, flexibility, and scalable device manufacturing. The dependence on fossil-based components raises environmental concerns, leading the scientific community toward sustainable solutions, aiming to reduce the accumulation of electronic waste (e-waste) in the environment and the emission of toxic gases, as well as to offer a circular solution in the sector. This review presents an in-depth overview of biobased polymeric materials in printed and organic (bio-)electronics. Firstly, the principal printing techniques are presented in detail. The review proceeds by outlining the various biobased synthetic and natural polymers, along with their blends, that are employed in the fabrication of biobased substrates for printed devices. Finally, the review emphasizes the existing challenges and constraints in the field of PE, along with the promising opportunities for its future advancement.

The increasing quest for greener and more sustainable polymeric materials has gained interest in the past few decades. Non-isocyanate polyurethanes (NIPUs) have attracted attention considering that they are produced through less toxic methods compared to the conventional polyurethanes (PUs) obtained from petroleum resources and toxic isocyanates. In this context, adipic acid, glycerol carbonate, 1,2-ethylenediamine, and 1,6-hexamethylenediamine, were used to synthesize NIPU_ethyl and NIPU_hexa, respectively. The obtained NIPUs were characterized using nuclear magnetic resonance spectroscopy (H-NMR spectra) and Fourier-transform infrared spectroscopy (FTIR) analysis, which verified the structures of the intermediate and final products. Calorimetric and dielectric studies provided direct and indirect support for the facilitated thermal stability of NIPU_ethyl and NIPU_hexa. Compared to the intermediate product, the NIPUs exhibit elevated glass transition temperatures, suggesting the formation of more rigid structures. The NIPUs were also tested in terms of swelling properties, and the results indicated that NIPU_hexa absorbs and withholds increased amounts of water for longer time periods compared to NIPU_ethyl, and their hydrolysis and enzymatic hydrolysis confirmed that NIPU_hexa is more stable in aqueous environments than NIPU_ethyl. Therefore, the successful production of adipic-acid-based NIPUs through a novel perspective of the polyaddition path is reported and complemented by the characterization of the obtained materials with several techniques.