Yadira Quiñones-Gutiérrez

Microalgal fucoxanthin is a marine xanthophyll relevant to environmental medicine because it links sustainable resource recovery with prevention-oriented research on environmentally driven metabolic disorders. Methods: This critical narrative review synthesizes recent peer-reviewed studies, related reviews, and regulatory documents on fucoxanthin chemistry, microalgal sources, cultivation, downstream processing, bioavailability enhancement, safety, and translational evidence. Findings: Diatoms and haptophytes, including Phaeodactylum tricornutum, Tisochrysis lutea, Isochrysis galbana, Nitzschia laevis, Cyclotella meneghiniana, and Conticribra weissflogii, are candidate production platforms, while Poterioochromonas malhamensis currently lacks the safety and regulatory evidence required for food use. Evidence for metabolic dysfunction-associated steatotic liver disease (MASLD), obesity, diabetes, inflammation, lipid metabolism, microbiota modulation, and chemoprevention remains predominantly preclinical or is derived from macroalgal or combined marine formulations. No randomized clinical trial evaluating a standardized microalgal fucoxanthin formulation with pharmacokinetic characterization was identified in the literature reviewed. Wastewater-derived biomass faces a strict regulatory barrier to oral human use and is currently best suited to environmental and agricultural applications unless contaminant clearance and product-specific safety are demonstrated. Conclusions: Bioavailability is constrained by instability, poor aqueous dispersibility, intestinal de-esterification to fucoxanthinol, and hepatic oxidation to amarouciaxanthin A, but encapsulation and lipid-matrix systems are promising. Translation requires authenticated strains, human-grade cultivation, validated processing, product-specific toxicology, regulatory dossiers, and controlled clinical studies.

Postoperative implant infections are strongly associated with bacterial adhesion and biofilm formation on metallic surfaces, particularly by Staphylococcus aureus. This study evaluated gentamicin-loaded nanotubular oxide formed on a Ti-24Zr-10Nb-2Sn alloy by anodization at 30 V for 30 min in an organic ethylene glycol/NH₄F electrolyte. The nanotubes had a mean length of 9.92 ± 0.60 µm and an inner diameter of 80.67 ± 6.45 nm (approximate aspect ratio 123). The normalized UV response at 262 nm reached 54.5 ± 3.7% of its final recorded value at 40 min. In the viable-count assay, gentamicin-loaded anodized samples yielded 17.5 ± 1.2 colonies/plate compared with 276.9 ± 12.6 colonies/plate for unloaded anodized samples. The loaded surface produced a 49.6 ± 2.5 mm inhibition zone against S. aureus. Together, these findings support gentamicin-loaded nanotubular oxide as a strategy for localized antibacterial activity on Ti-24Zr-10Nb-2Sn.

Marine algae sustain primary productivity, nutrient cycling, and coastal carbon regulation, yet warming, salinity fluctuations, acidification, and nutrient/metal loading increasingly challenge their physiology, and evidence linking adaptation to biotechnological value remains fragmented. This narrative review synthesizes physiological, biochemical, and transcriptomic studies (2016–2026) on marine micro- and macroalgae exposed to thermal, saline, light/oxidative, nutrient, heavy-metal, and acidification stress; a few non-marine extremophile taxa are included and flagged as mechanistic comparators. Across taxa, algae rely on recurrent strategies—osmolyte accumulation, antioxidant/photoprotective pigments, fatty-acid desaturation, metal chelation, and phytohormone-mediated (ABA, SA, MeJA) signalling coupled to ribosome-biogenesis upregulation—that appear to restore redox and osmotic homeostasis. These phenotypes underpin biofuel, bioremediation, blue-carbon, and bioplastic applications, ranked on a Technology Readiness Level scale from wastewater bioremediation and aquaculture co-culture (TRL 6–7) to biodiesel and blue-carbon crediting (TRL 3) and photoprotection-trait transfer (TRL 2). We propose a reaction-level conceptual framework in which ribosome-biogenesis control and ABA/SA/MeJA signalling act as a testable stress-integration hub, presented explicitly as a hypothesis rather than an established mechanism. Stress tolerance and circular-economy value may be mechanistically linked, but most evidence derives from short-term, single-species laboratory exposures, remains taxonomically narrow, and macroalga-specific comparative laboratory data are scarce.

Postoperative infections in orthopedic implants remain a major complication, particularly in open fractures, where early bacterial colonization and the limited bioactivity of titanium alloys hinder osseointegration. This study reports a hierarchical coating synthesized in situ on Ti-407 alloy, integrating bioactive and antibacterial functions. TiO₂ nanotube arrays were formed by anodization and subsequently functionalized by sequential electrodeposition of Ag nanoparticles and doped hydroxyapatite (HA) (Ca, P, Mg, Zn). SEM/EDS confirmed uniform coatings with a Ca/P ratio near stoichiometric HA (1.61). Agar diffusion assays against E. coli ATCC® 25922™ revealed well-defined inhibition zones, confirming the antibacterial efficacy of the coatings. These findings highlight the potential of hierarchical coatings to enhance bone integration while reducing infection risk in orthopedic implants.