Marta Pacheco

A paper-based electrochemical aptasensor (PEA) is reported for the simultaneous detection of extracellular dopamine (DA) and serotonin (SE) in human brain samples, enabling the assessment of neurotransmitter imbalances associated with Alzheimer's disease (AD). The PEA integrates a dual-selectivity strategy that combines aptamer-mediated molecular recognition with potential-resolved electrochemical neurotransmitters discrimination, allowing reliable differentiation between healthy and AD-diagnosed left prefrontal cortex tissues based on altered dopaminergic and serotonergic levels. Thiolated aptamers immobilized onto gold nanoparticles (AuNPs) at the paper electrode interface provide selective neurotransmitter biorecognition, while the distinct oxidation potentials of DA (+ 0.10 V) and SE (+ 0.25 V vs. Ag/AgCl) enable their label-free, simultaneous quantification on a single disposable electrode. The PEA read biologically meaningful concentration shifts across a clinically relevant dynamic range, spanning levels characteristic of healthy tissue to those observed in advanced pathological stages. The PEA approach highlights its potential for liquid biopsy-oriented neurochemical monitoring and supports its application in multiplexed biosensing within organ-on-a-chip systems, enabling early diagnostic strategies for neurodegenerative diseases.

Indane and phenylpropyl derivatives are interesting precursors for the synthesis of bioactive compounds, including those with antifungal or anti-inflammatory properties. In light of the increasing interest in the biocatalytic potential of marine-derived fungi, a study was conducted in which the substrates indene (1), indanone (2), 5-chloroindanone (2a), 1-phenylpropyl acetate (3), and 1-(4′-chlorophenyl)propyl acetate (3a) were biotransformed by the marine sediment-derived fungal strains Purpureocillium lilacinum BC17-2 and Emericellopsis maritima BC17. Fermentations led to the isolation of sixteen derivatives, which exhibited noteworthy stereoselectivities. The absolute configurations of the optically active indane and phenylpropyl derivatives isolated were determined through electronic circular dichroism and optical rotation dispersion computational calculations. Furthermore, given the known biocatalytic potential of the phytopathogenic fungus Botrytis cinerea to modify the structures of certain antifungal phenylpropyl derivatives, substrates 3 and 3a were also subjected to biotransformation by the strain B. cinerea UCA992. The antifungal activities of the biotransformation products (R)-5, (S)-6, syn-(1S,2R)-7, anti-(1R,2R)-7, (R)-8, (R)-9, threo-(1R,2R)-11, and erythro-(1R,2S)-11 were evaluated against B. cinerea UCA992 using a resazurin-based microdilution method.

A novel microfluidic paper-based analytical device with dual colorimetric and electrochemical detection (dual µPAD) was developed for the assessment of transferrin saturation (TSAT) in samples from ischemic stroke patients. TSAT was calculated by the ratio between transferrin-bound iron, which was colorimetrically measured, and total iron-binding capacity, which was electrochemically measured. To this end, a µPAD was smartly designed with integrated both colorimetric and electrochemical detection reservoirs communicated with and microchannel acting as a chemical reactor and with preloading/storing capabilities (reagent-free device). This approach allowed the dual and simultaneous determination of both parameters, providing an improvement in the reliability and precision of the results benefiting an independent signal principle and processing. µPADs were validated by analyzing a certified reference material showing excellent accuracy (E_r ≤ 5 %) and precision (RSD ≤ 2 %) and then they were applied to the analysis of diagnosed serum samples from ischemic stroke patients. The results were compared to those provided by a free-interference method (urea-PAGE). Impressively, both methods exhibited a good correlation (r = 0.96, p < 0.05), and no significant differences were found between both (slope 1.0 ± 0.1 and the intercept 1 ± 4, p < 0.05), demonstrating the excellent accuracy of our approach during the analysis of complex samples from ischemic stroke patients, using just 90 μL of clinical samples and taking less than 90 min in comparison with the 18 hours required by the urea-PAGE approach. The developed fully integrated colorimetric-electrochemical µPAD is a promising ready to be used reagent-free device for the point-of-care testing of TSAT, which can be used to assist physicians in the fast diagnosis and prognosis of ischemic stroke, where the time to decide is crucial for patient’s survival.

Herein we report the coating of visible light-driven polycaprolactone (PCL) based micromotors with an anti-biofouling poly lactic- co -glycolic acid (PLGA) layer for effective navigation and detoxification in blood samples.

Micro‐ and nanomotors are micro‐ and nanostructures capable of autonomous movement and collective behavior, mimicking natural counterparts. This review aims to give a recent perspective on micro‐ and nanomotors driven by intelligent mechanisms in action under the cooperative effect of the swarm of micromotors as their distinctive feature. Different energy sources and the factors that can influence cooperative micromotor motion are comprehensively covered, along with the underlying phenomena and related applications. The motion ability of micro/nanomotors, along with capabilities to reach a targeted destination, holds considerable promise to address remaining challenges in the environmental and biomedical fields.

A light‐driven multifunctional Janus micromotor for the removal of bacterial endotoxins and heavy metals is described. The micromotor was assembled by using the biocompatible polymer polycaprolactone for the encapsulation of CdTe or CdSe@ZnS quantum dots (QDs) as photoactive materials and an asymmetric Fe₃O₄ patch for propulsion. The micromotors can be activated with visible light (470–490 nm) to propel in peroxide or glucose media by a diffusiophoretic mechanism. Efficient propulsion was observed for the first time in complex samples such as human blood serum. These properties were exploited for efficient endotoxin removal using lipopolysaccharides from Escherichia coli O111:B4 as a model toxin. The micromotors were also used for mercury removal by cationic exchange with the CdSe@ZnS core–shell QDs. Cytotoxicity assays in HeLa cell lines demonstrated the high biocompatibility of the micromotors for future detoxification applications.

A light‐driven multifunctional Janus micromotor for the removal of bacterial endotoxins and heavy metals is described. The micromotor was assembled by using the biocompatible polymer polycaprolactone for the encapsulation of CdTe or CdSe@ZnS quantum dots (QDs) as photoactive materials and an asymmetric Fe₃O₄ patch for propulsion. The micromotors can be activated with visible light (470–490 nm) to propel in peroxide or glucose media by a diffusiophoretic mechanism. Efficient propulsion was observed for the first time in complex samples such as human blood serum. These properties were exploited for efficient endotoxin removal using lipopolysaccharides from Escherichia coli O111:B4 as a model toxin. The micromotors were also used for mercury removal by cationic exchange with the CdSe@ZnS core–shell QDs. Cytotoxicity assays in HeLa cell lines demonstrated the high biocompatibility of the micromotors for future detoxification applications.