A 3D graphene foam made of interconnected multilayer graphene flakes was produced on optical fibres (OF) by laser-induced transformation of a polyimide (PI) film coated on the OF cladding. This material, known as la-ser-induced graphene (LIG), was explored in the electrochemical detection and quantification of dopamine (DA) at physiologically relevant concentrations in the presence of the most relevant interfering molecules in biological fluids, ascorbic acid (AA) and uric acid (UA). The measured limit of detection is 100 nM, the linear range is 0.1 to 5 μM and a maximum sensitivity of 5.0 µA µM−1 cm−2 was obtained for LIG decorated with Pt nanoparticles (NPs). Moreover, immunity to AA and UA interference and to fouling was attained by decorating the LIG elec-trode with Pt NPs and coating with Nafion. These figures of merit underlines the potential of these sensors for the quantification of physiologically relevant concentrations of DA in biological fluids, paving the way for the development of hybrid electrochemical/optical sensing actuating platforms in a lab-on-fibre configuration, with relevant applications in biomedical engineering. The advantages of this hybrid arrangement include the possi-bility of in-situ counterproofing, extended measuring ranges, photoelectrochemical detection and the probing of inaccessible places. This elegant approach can also provide a simple and cost-effective way to fabricate biomed-ical devices with extended functionality, such as medical optical probes with added electrochemical capabilities, optogenetics combined with local electrochemical detection, among others.

The saltmarsh plant Halimione portulacoides was shortly exposed to realistic levels of inorganic mercury (iHg), aiming to investigate adaptative processes of the roots and leaves regarding re-dox homeostasis, physiology, and Hg accumulation. Plants were collected at a contaminated (CONT) and a reference (REF) site, addressing the interference of contamination background. The influence of major abiotic variables (i.e., temperature and light) was also examined. Total Hg lev-els, antioxidant enzymes, lipid peroxidation (LPO), and photosynthetic activity were analyzed after 2 and 4 hours of exposure. Accumulation of iHg in the roots was noticed poorly, and no translocation to stems and leaves was found, but plants from CONT seemed more prone to iHg uptake (in winter). Despite that, antioxidant modulation in roots and leaves was found, disclos-ing, in winter, higher thresholds for the induction of enzymatic antioxidants in CONT leaves compared to REF, denoting that the former are better prepared to cope with iHg redox pressure. Consistently, CONT leaves exposed to iHg had remarkably lower LPO levels. Exposure did not impair the photosynthetic activity, pinpointing H. portulacoides ability to cope with iHg toxicity under a very short-term exposure. Biochemical changes were noticed before enhancements in ac-cumulation, reinforcing the relevance of these responses in precociously signaling iHg toxicity.