Monique Deon

Silver (AgNP) and gold (AuNP) nanoparticles are notable in nanomedicine for their unique properties and strong antibacterial effects; however, formulating them into skin-applied systems that preserve bioactivity while controlling nanoparticle exposure remains challenging. Herein, semisolid extrusion 3D printing of chitosan nanocomposite hydrogels loaded with AgNPs or AuNPs was used to manufacture personalized topical films with antimicrobial performance and minimized skin penetration risk. AgNPs and AuNPs were synthesized with comparable nanoscale dimensions (11.83 ± 3.74 nm and 11.67 ± 1.96 nm), enabling their uniform incorporation into chitosan matrices. The resulting inks presented topical-compatible pH (>4.0) and pronounced thixotropy with >90% viscosity recovery, translating into adequate performance in 3D printing. Nanoparticle incorporation afforded the tuning of properties such as swelling, mechanical behavior, and bioadhesion. Functionally, AgNP-loaded films exhibited the strongest broad-spectrum activity against Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans. Ex vivo porcine skin studies indicated that free nanoparticles were detectable only in the stratum corneum, whereas metals were not detected after application of the 3D-printed films, supporting effective nanoparticle confinement by the chitosan matrix. These results position 3D-printed chitosan-nanoparticle films as a promising platform for customizable antimicrobial dressings for infected skin wounds.

In this work, a novel thin-film microextraction (TF-SPME) device was developed using semi-solid extrusion 3D printing, aiming to provide a sustainable and customizable tool for the environmental monitoring of pesticides in water. The device was fabricated from a nanocomposite of chitosan (CS) and multi-walled carbon nanotubes (MWCNT) and the printing approach enabled direct shaping of the extraction films under mild conditions. Rheological evaluation confirmed that the CS-based hydrogels, with and without MWCNT, possess pseudoplastic and thixotropic behavior, suitable characteristics for extrusion-based printing. Films measuring 20 mm × 5 mm × 1 mm were designed in a geometry compatible with TF-SPME strips, and after printing, they were evaluated for the hydrolytic stability of chitosan. Both CS and CS/MWCNT films exhibited similar swelling index in water (287 ± 7 % and 244 ± 7 %, respectively) and maintained structural integrity without disintegration in either water or acetonitrile throughout the evaluation period, regardless of the presence of MWCNT. The printed devices were successfully applied to the thin-film solid-phase microextraction of organochlorine and organophosphorus pesticides in water followed by analysis using gas chromatography coupled to mass spectrometry (GC-MS). Better extraction efficiency and linear response were observed for the MWCNT-containing 3D-printed films for seven evaluated pesticides (alpha-BHC, aldrin, endosulfan I (alpha), dieldrin, 4,4-DDE, 4,4-DDD, and phorate). Molecular dynamics simulations suggest that the presence of CNT is associated with microstructural and hydration effects within the chitosan matrix, which favor interactions between the analytes and the sorbent phase. The limits of quantification were in the range 50–200 μg L^-1. This study highlights the potential of semi-solid extrusion 3D printing in the development of green, functional, and versatile analytical platforms for monitoring of organic pollutants in environmental samples.

A low cost, eco-friendly, reproducible and portable sensor was developed for 17-α-ethynylestradiol hormone (EE2) in drinking water. The sensor was based on a screen-printed electrode prepared with a carbon nanocomposite material constituted by graphite and magnetite embedded in porous silica. Firstly, MCM-41 type silica was prepared in the presence of previously synthesized magnetite nanoparticles. This material presented high surface area (570 m2 g-1), unimodal pore size distribution with maximum at 2.75 nm, and appreciable magnetization (12 emu g-1). Afterwards, graphite was added and this carbon-nanocomposite was used directly as ink in the manufacturing of a screen-printed electrode, in just one print step, on the first time. This screen-printed electrode presented linearity in the EE2 concentration range between 0.5 and 5.0 µmol L-1, a low detection limit (0.11 µmol L-1), a quantification limit of 0.36 µmol L-1 and satisfactory reproducibility. The sensor also showed good performance in the determination of EE2 in a drinking water real sample.

Glioblastoma presents significant challenges in neuro-oncology due to its aggressive nature, drug resistance, and restrictions imposed by the blood-brain barrier. Ivermectin (IVM), known for its antiparasitic properties, has been highlighted as a promising treatment for tumors and an alternative therapy for glioma, although it exhibits low oral bioavailability. Therefore, we investigated the in vivo effect of IVM encapsulation in organic and inorganic nanosystems, first screened in vitro against different tumor cells and subsequently evaluated in vitro and in vivo glioma models. We produced IVM-loaded poly(ε-caprolactone) nanocapsules (IVM-NC) using the interfacial deposition method, and IVM-loaded nanostructured silica particles (IVM-MCM) by loading IVM into commercial MCM-41 silica using the incipient wetness method. IVM-NC had a nanometric size (190 nm), a unimodal size distribution (span <2), and a high encapsulation efficiency (100% at 1 mg/mL). IVM-MCM exhibited a well-organized hexagonal mesoporous structure and high drug loading (0.12 mg/mg). Nanoencapsulated IVM significantly reduced the viability of various cancer cell lines, particularly glioma cell lines, which led us to evaluate them in a preclinical glioma model. We implanted adult male Wistar rats with C6 cells. Intranasal delivery of IVM-NC (60 μg/rat/day for 10 days) resulted in a larger decrease in tumor size compared with the group treated with free IVM, along with histopathological improvements. Treatment with IVM-MCM did not decrease the tumor size. However, both treatments were well-tolerated, with no adverse effects on weight, biochemical, or hematological parameters, or lung histology. Furthermore, the effective equivalent dose of IVM (26 μg/kg) in the rat glioma model was lower than the approved human dose for parasitic infections. This study marks the first exploration of IVM delivery to the brain. In summary, nasal administration of nanoencapsulated IVM via nanocapsules presents a promising avenue for targeted therapy against glioblastoma, with potential implications for clinical translation.