Agostina Cammarata

Plastic pollution has become a global environmental issue, yet little is known about how plastics degrade and interact with microbes under polar conditions, especially upon entering the marine environment. Here, we report the first in situ time-series experiment investigating early microbial colonization and surface oxidation of virgin plastics in Antarctic coastal waters. Virgin pellets of polystyrene (PS), low-density polyethylene (LDPE), and polyethylene terephthalate (PET) were deployed in Potter Cove (King George/25 de Mayo Island) for 31 days. Biofilm communities were characterized using 16S rRNA amplicon sequencing, while polymer surface chemistry was assessed by Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR). Across all polymers, plastisphere assemblages were dominated by psychrophilic or psychrotolerant taxa. Plastic-associated communities showed consistent temporal changes over the 31-day exposure, with shifts in the relative abundance of taxa associated with different stages of biofilm development. Exposure time was a stronger determinant of community composition than polymer type. FTIR analyses revealed significant surface oxidation in PS and LDPE, particularly at days 21 and 31, with increases in hydroxyl, carbonyl, and carbon–oxygen indices. PET showed great variability and no consistent oxidative signals over the study period. The chemical shifts partially covaried with taxa associated with later sampling points, suggesting potential, but not yet conclusive, links between biofilm succession and polymer weathering. Our results provide some novel insights into the early dynamics of microbial colonization on plastic surfaces and polymer surface alteration in Antarctic waters, highlighting the importance of integrating microbial and chemical perspectives to understand plastic fate in polar ecosystems.

This study focuses on a green and sustainable nanoplatform for the delivery of therapeutic agents, based on gold nanoparticles (AuNPs) synthesized using PEO-PPO block copolymers (F127, F68, P85, and their F127:P85 combination) as dual-function reducing and stabilizing agents. This eco-friendly approach eliminates the need for toxic chemical reductants, adheres to green chemistry principles, and yields highly stable, biocompatible nanosystems. The resulting polymer-stabilized AuNPs were associated with doxycycline (DOXY), a mitochondrial biogenesis inhibitor with radiosensitizing properties, and characterized using UV-Vis spectroscopy, dynamic light scattering (DLS), transmission electron microscopy (TEM), and X-ray fluorescence (XRF). The nanoparticles exhibited high colloidal stability, with tunable hydrodynamic diameters modulated by the copolymer composition. In vitro studies on A-375 and IIB-MEL-J melanoma cell lines revealed that DOXY-associated AuNPs, combined with gamma radiation (2 Gy, 137Cs), significantly enhanced radiosensitivity, reducing both cell viability and clonogenic survival. The physicochemical features of the nanosystems, particularly particle size and surface composition, influenced cellular uptake and therapeutic response. Notably, AuNPs stabilized with F127:P85 copolymer combination (∼19 nm) outperformed those with F127 (∼30 nm), despite displaying slightly higher polydispersity. Compared to Turkevich AuNPs, our copolymer-coated nanosystems demonstrated superior colloidal stability and cellular internalization. These findings highlight the potential of green-synthesized AuNPs as multifunctional, biocompatible platforms for therapeutic delivery, supporting the development of effective and environmentally responsible multimodal cancer therapies. Moreover, the simplicity, scalability, and cost-effectiveness of the synthesis process support its potential for future translational applications.

Introduction: Currently nanotechnology has radically changed the diagnosis of many human pathologies. The aim of this work is to obtain silver nanoparticles for hybrid imaging (99mTc-AgNPs-ICG) having potential clinical imaging applications. Materials and method: We mixed 2 ml of ascorbic acid (1.7x10-4 M), 5 mCi of 99mTcO4- , 2 ml of citric acid (8.0x10-4 M) and 0.5 ml of silver nitrate (2.5x10-3 M). Solution pH was 5, and it was shaken for 20 minutes at 37º C. Afterwards, 2 µL of Indocyanine Green (1.3x10-3 M) was added (99mTc-AgNPs-ICG). Physiochemical properties of the solution were characterized by UV (λ1 = 420 nm, λ2 = 254 nm) and gamma detector. Fluorescence image, particle size and IR spectrum were evaluated. Results: Silver nanoparticles were obtained in aqueous solution a pH of 5. Their pH, color and spectrum were stable for seven days. Furthermore, the principal peak characterized by HPLC, UV and Gamma detector had similar retention times. Its UV spectrum showed an absorption band of 420 nm, which corresponds to the plasmon absorption band of these nanoparticles. The particle size was 46 nm ± 1.5 nm. The IR spectrum showed absorption bands in 3193, 2624, 1596 y 1212 cm-1. Conclusions: We describe for the first time in literature the synthesis of hybrid (radioactive and fluorescent) silver nanoparticles. Their physiochemical properties were characterized, being stable and their labelling was reproducible having potential biomedical applications. Received for review: November 2023. Accepted for publication: February 2024. Correspondence: Centro de Investigaciones Nucleares, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay. Mataojo 2055, P.O. 11400, Montevideo, Uruguay. Tel: (+5982) 5250901/108; fax: (+5982) 5250895. Contact e-mail: pabloc7@gmail.com This article was approved by the Editorial Committee. Introducción: actualmente la nanotecnología ha cambiado radicalmente el diagnóstico de muchas patologías humanas. El objetivo de este trabajo es obtener nanopartículas de plata para imagen híbrida (99mTc-AgNPs-ICG) que tengan potenciales aplicaciones clínicas en imagen. Materiales y método: se mezclaron 2 ml de ácido ascórbico (1,7x10-4 M), 5 mCi de 99mTcO4- , 2 ml de ácido cítrico (8,0x10-4 M) y 0,5 ml de nitrato de plata (2,5x10-3 M). El pH de la solución fue 5, y se agitó durante 20 minutos a 37º C. A continuación, se añadieron 2 µl de verde de indocianina (1,3x10-3 M) (99mTc-AgNPs-ICG). Las propiedades fisicoquímicas de la solución se caracterizaron mediante UV (λ1 = 420 nm, λ2 = 254 nm) y detector gamma. Se evaluaron la imagen de fluorescencia, el tamaño de las partículas y el espectro IR. Resultados: se obtuvieron nanopartículas de plata en solución acuosa a un pH de 5. Su pH, color y espectro fueron estables durante siete días. Además, el pico principal caracterizado por HPLC, UV y detector Gamma tenía tiempos de retención similares. Su espectro UV mostró una banda de absorción de 420 nm, que corresponde a la banda de absorción plasmónica de estas nanopartículas. El tamaño de las partículas era de 46 nm ± 1,5 nm. El espectro IR mostró bandas de absorción en 3193, 2624, 1596 y 1212 cm-1. Conclusiones: describimos por primera vez en la literatura la síntesis de nanopartículas de plata híbridas (radioctivas y fluorescentes). Se caracterizaron sus propiedades fisicoquímicas, siendo estables y su etiquetado fue reproducible teniendo potenciales aplicaciones biomédicas. Recibido para revisión: noviembre 2023. Aceptado para publicación: febrero de 2024. Correspondencia: Centro de Investigaciones Nucleares, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay. Mataojo 2055, P.O. 11400, Montevideo, Uruguay. Tel: (+5982) 5250901/108; fax: (+5982) 5250895. E-mail de contacto: pabloc7@gmail.com Este artículo fue aprobado por el Comité Editorial. Introdução: atualmente, a nanotecnologia mudou radicalmente o diagnóstico de muitas patologias humanas. O objetivo deste trabalho é obter nanopartículas de prata para imagens híbridas (99mTc-AgNPs-ICG) com possíveis aplicações de imagens clínicas. Materiais e método: misturamos 2 ml de ácido ascórbico (1,7x10-4 M), 5 mCi de 99mTcO4- , 2 ml de ácido cítrico (8,0x10-4 M) e 0,5 ml de nitrato de prata (2,5x10-3 M). O pH da solução era 5 e ela foi agitada por 20 minutos a 37º C. Em seguida, foram adicionados 2 µL de indocianina verde (1,3x10-3 M) (99mTc-AgNPs-ICG). As propriedades físico-químicas da solução foram caracterizadas por UV (λ1 = 420 nm, λ2 = 254 nm) e detector gama. A imagem de fluorescência, o tamanho das partículas e o espectro de infravermelho foram avaliados. Resultados: as nanopartículas de prata foram obtidas em solução aquosa com pH de 5. Seu pH, cor e espectro permaneceram estáveis por sete dias. Além disso, o pico principal caracterizado por HPLC, UV e detector gama teve tempos de retenção semelhantes. Seu espectro de UV mostrou uma banda de absorção de 420 nm, que corresponde à banda de absorção plasmônica dessas nanopartículas. O tamanho da partícula foi de 46 nm ± 1,5 nm. O espectro de IV mostrou bandas de absorção em 3193, 2624, 1596 e 1212 cm-1. Conclusões: descrevemos pela primeira vez na literatura a síntese de nanopartículas de prata híbridas (radioativas e fluorescentes). Suas propriedades físico-químicas foram caracterizadas, sendo estáveis e sua rotulagem foi reprodutível, com possíveis aplicações biomédicas. Recebido...

Introducción: actualmente la nanotecnología ha cambiado radicalmente el diagnóstico de muchas patologías humanas. El objetivo de este trabajo es obtener nanopartículas de plata para imagen híbrida (99mTc-AgNPs-ICG) que tengan potenciales aplicaciones clínicas en imagen. Materiales y método: se mezclaron 2 ml de ácido ascórbico (1.7 x10-4 M), 5 mCi de 99mTcO4-, 2 ml de ácido cítrico (8.0 x 10-4 M) y 0.5 ml de nitrato de plata (2.5 x 10-3 M). El pH de la solución fue 5, y se agitó durante 20 minutos a 37º C. A continuación, se añadieron 2 µl de verde de indocianina (1.3 x 10-3 M) (99mTc-AgNPs-ICG). Las propiedades fisicoquímicas de la solución se caracterizaron mediante UV (λ1 = 420 nm, λ2 = 254 nm) y detector gamma. Se evaluaron la imagen de fluorescencia, el tamaño de las partículas y el espectro IR. Resultados: se obtuvieron nanopartículas de plata en solución acuosa a un pH de 5. Su pH, color y espectro fueron estables durante siete días. Además, el pico principal caracterizado por HPLC, UV y detector Gamma tenía tiempos de retención similares. Su espectro UV mostró una banda de absorción de 420 nm, que corresponde a la banda de absorción plasmónica de estas nanopartículas. El tamaño de las partículas era de 46 nm ± 1,5 nm. El espectro IR mostró bandas de absorción en 3193, 2624, 1596 y 1212 cm-1. Conclusiones: describimos por primera vez en la literatura la síntesis de nanopartículas de plata híbridas (radioactivas y fluorescentes). Se caracterizaron sus propiedades fisicoquímicas, siendo estables y su etiquetado fue reproducible teniendo potenciales aplicaciones biomédicas. Recibido para evaluación: noviembre 2023. Aceptado para publicación: febrero 2024. Correspondencia: Centro de Investigaciones Nucleares, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay. Mataojo 2055, C.P. 11400, Montevideo, Uruguay. Tel.: (+5982) 5250901/108; fax: (+5982) 5250895.E-mail de contacto: xcdamata@gmail.com Este artículo fue aprobado por el Comité Editorial.

Zinc phthalocyanines have demonstrated a wide range of applications as photosensitisers, particularly in organic synthesis, photocatalysis and photodynamic therapy. Although the introduction of ionic groups on the macrocycle periphery increases their water solubility, aggregation phenomena remain as a significant drawback for their application. In this study, amphiphilic sulfonatocalix[4]arene‐based micelles were used to promote the monomerization of a cationic phthalocyanine through host–guest interactions. A comprehensive spectroscopic characterization was conducted, varying the concentration of sulfonatocalix[4]arene, and binding parameters were calculated to determine the optimal conditions for complete monomerization of the photosensitizer in water. Under these conditions, the combination of sulfonatocalix[4]arene and the photosensitizer activated its photophysical activity in aqueous media, showing significant singlet oxygen photoproduction, photocatalytic capability and photostability.