Michela Sugni

Nanoplastics are emerging contaminants of increasing concern in marine ecosystems, yet their in vivo biodistribution and biological effects in benthic organisms remain poorly understood. In this study, we provide an integrated, multi-level assessment of the uptake, translocation, and biological effects of polyethylene terephthalate nanoplastics (PET-NPs) in the brittle star Ophiactis virens, an ecologically relevant benthic invertebrate with high regenerative capacity.Individuals were exposed for 14 days to environmentally relevant (0.05 and 0.5 µg/mL) and worst-case (5 µg/mL) concentrations of PET-NPs. A multidisciplinary approach combining confocal and electron microscopy, behavioural assays, regeneration analysis, and biochemical biomarkers was applied. Imaging analyses revealed a dose-dependent accumulation of PET-NPs on the body surface and within the vestibulum and digestive systems, demonstrating particle ingestion. Notably, PET-NPs were detected also within internal tissues and intracellular vesicles, providing in vivo evidence of translocation across epithelial barriers and cellular internalization.At the organismal level, exposure resulted in increased mortality and impaired righting behaviour at higher concentrations. Importantly, arm regeneration was significantly reduced at intermediate and high concentrations, identifying regeneration as a sensitive and integrative endpoint of nanoplastic exposure. At the biochemical level, a decrease in superoxide dismutase activity suggested a modulation of antioxidant responses, although no clear oxidative damage was observed.Overall, this study provides one of the first integrated in vivo demonstrations of nanoplastic translocation from external exposure to intracellular compartments in a burrowing echinoderm, linking biodistribution to functional impairment. Arm regeneration emerges as a sensitive and ecologically relevant endpoint for assessing nanoplastic effects in marine benthic organisms. These findings highlight the potential ecological risks of PET-NPs accumulation in sediment-associated organisms and support the use of O. virens as a valuable unconventional model for nanoplastic ecotoxicology.

Preclinical investigations involving in vivo animal studies, are considered a crucial and mandatory step in pharmacological industry regulations. In recent years, as the ethical concerns associated with animal experimentation are becoming more relevant, substantial research efforts have been directed towards the development of novel in vitro methodological approaches aimed at minimizing the utilization of animals. Among those, three-dimensional (3D) cell culture systems have become one of the most promising substitutes for animal models. Skeletal muscle can be affected by genetic disorders and injuries. In this study, two types of 3D scaffolds (Coll and CollMA), prepared starting from a fibrillar collagen suspension extracted from sea urchin food waste, were used as platforms for the generation of 3D skeletal muscle tissue models. The scaffolds were cellularized with C2C12 myoblasts. As the culture period progressed, C2C12 cells gradually infiltrated and were viable throughout both scaffold types, establishing a multilayered cellular population. In the CollMA scaffold, the reciprocal Pax7/MyoD expression pattern suggests a progression of myoblasts towards myogenic commitment. Taken together, our results, although preliminary, suggest that sea urchin–derived collagen matrix represents a promising scaffold for skeletal muscle tissue engineering.

Marine organisms offer a vast and still underutilized reservoir of biomolecules and biomaterials with promising applications across various human sectors. Among them, sea urchins—such as Paracentrotus lividus —stand out due to their high content of biogenic carbonates, making them particularly relevant within circular economy strategies and blue growth frameworks. P. lividus is a prized delicacy in Italy and other countries; however, only the gonads (roe) are consumed, while the majority of the biomass is discarded as waste. Despite ongoing efforts to establish full‐cycle aquaculture systems, the market supply in Europe remains predominantly reliant on wild harvesting, leading to overexploitation and depletion of natural populations in several regions. In this study, we explored the potential to valorize waste generated by the seafood industry, particularly the carbonate‐rich test of P. lividus , by incorporating it into experimental aquafeeds. The rationale was that a biogenic carbonate source, naturally enriched with magnesium and antioxidants derived from pigments in the test and spines, could enhance both somatic and gonadal growth in cultured urchins. Results demonstrated that it is possible to formulate a stable, effective feed that supports gonad development. Moreover, feeds containing sea urchin‐derived biocarbonates exhibited higher antioxidant activity compared to formulations based on commercial inorganic calcium carbonate, even when supplemented with synthetic antioxidants. These findings suggest that incorporating biogenic waste into aquafeeds not only supports sustainable aquaculture practices but may also improve feed shelf life and promote better health and performance in cultured sea urchins.

Approximately 75,000 tons of different sea urchin species are globally harvested for their edible gonads. Applying a circular economy approach, we have recently demonstrated that non-edible parts of the Mediterranean Sea urchin Paracentrotus lividus can be fully valorized into high-value products: antioxidant pigments (polyhydroxynaphthoquinones—PHNQs) and fibrillar collagen can be extracted to produce innovative biomaterials for biomedical applications. Can waste from other edible sea urchin species (e.g., Sphaerechinus granularis) be similarly valorised? A comparative study on PHNQs and collagen extraction was conducted. PHNQ extraction yields were compared, pigments were quantified and identified, and antioxidant activities were assessed (by ABTS assay) and correlated to specific PHNQ presence (i.e., spinochrome E). Similarly, collagen extraction yields were evaluated, and the resulting collagen-based biomaterials were compared in terms of their ultrastructure, degradation kinetics, and resistance to compression. Results showed a partially similar PHNQ profile in both species, with significantly higher yield in P. lividus, while S. granularis exhibited better antioxidant activity. P. lividus samples showed higher collagen extraction yield, but S. granularis scaffolds showed higher stability. In conclusion, waste from different species can be successfully valorised through PHNQ and collagen extraction, offering diverse applications in the biomedical field, according to specific technical requirements.

Echinoderms (starfish, sea-urchins and their close relations) possess a unique type of collagenous tissue that is innervated by the motor nervous system and whose mechanical properties, such as tensile strength and elastic stiffness, can be altered in a time frame of seconds. Intensive research on echinoderm ‘mutable collagenous tissue’ (MCT) began over 50 years ago, and over 20 years ago, MCT first inspired a biomimetic design. MCT, and sea-cucumber dermis in particular, is now a major source of ideas for the development of new mechanically adaptable materials and devices with applications in diverse areas including biomedical science, chemical engineering and robotics. In this review, after an up-to-date account of present knowledge of the structural, physiological and molecular adaptations of MCT and the mechanisms responsible for its variable tensile properties, we focus on MCT as a concept generator surveying biomimetic systems inspired by MCT biology, showing that these include both bio-derived developments (same function, analogous operating principles) and technology-derived developments (same function, different operating principles), and suggest a strategy for the further exploitation of this promising biological resource.

In this review, we focused on recent efforts in the design and development of materials with biomimetic properties. Innovative methods promise to emulate cell microenvironments and tissue functions, but many aspects regarding cellular communication, motility, and responsiveness remain to be explained. We photographed the state-of-the-art advancements in biomimetics, and discussed the complexity of a “bottom-up” artificial construction of living systems, with particular highlights on hydrogels, collagen-based composites, surface modifications, and three-dimensional (3D) bioprinting applications. Fast-paced 3D printing and artificial intelligence, nevertheless, collide with reality: How difficult can it be to build reproducible biomimetic materials at a real scale in line with the complexity of living systems? Nowadays, science is in urgent need of bioengineering technologies for the practical use of bioinspired and biomimetics for medicine and clinics.

The mutable collagenous tissue (MCT) of echinoderms possesses biological peculiarities that facilitate native collagen extraction and employment for biomedical applications such as regenerative purposes for the treatment of skin wounds. Strategies for skin regeneration have been developed and dermal substitutes have been used to cover the lesion to facilitate cell proliferation, although very little is known about the application of novel matrix obtained from marine collagen. From food waste we isolated eco-friendly collagen, naturally enriched with glycosaminoglycans, to produce an innovative marine-derived biomaterial assembled as a novel bi-layered skin substitute (Marine Collagen Dermal Template or MCDT). The present work carried out a preliminary experimental in vivo comparative analysis between the MCDT and Integra, one of the most widely used dermal templates for wound management, in a rat model of full-thickness skin wounds. Clinical, histological, and molecular evaluations showed that the MCDT might be a valuable tool in promoting and supporting skin wound healing: it is biocompatible, as no adverse reactions were observed, along with stimulating angiogenesis and the deposition of mature collagen. Therefore, the two dermal templates used in this study displayed similar biocompatibility and outcome with focus on full-thickness skin wounds, although a peculiar cellular behavior involving the angiogenesis process was observed for the MCDT.