Ángel Ríos

Olaparib, a potent PARP-inhibitor, represents a breakthrough in advanced ovarian cancer therapy, yet its clinical management is often challenged by severe adverse effects and high inter-individual pharmacokinetic variability. Here, we report a portable and orthogonal spectroelectrochemical workflow coupling differential pulse voltammetry and surface-enhanced Raman spectroscopy (EC/SERS) for rapid screening and quantitative determination of olaparib in human serum samples. A high-performance nanostructured hybrid platform was fabricated using screen-printed carbon electrodes modified with carbon nanofibers and gold nanoparticles (AuNPs/CNFs-SPCE). Key experimental and instrumental parameters were systematically optimised using portable electrochemical and 785-nm Raman devices. Under optimised conditions, the irreversible 2e-/2H+ oxidation mechanism yielded oxidised olaparib in situ, which was then identified via SERS. The quantification of olaparib was achieved by both electrochemical and SERS techniques, providing an excellent linear response from 1.3 to 16.11 μM (R²=0.999 for EC and R²=0.998 for SERS) with low limits of detection and quantification and excellent accuracy and precision. The method was applied in human serum samples achieved by the standard addition method, showing remarkable accuracy and precision, with recoveries close to 100% after a simple protein precipitation protocol. Robust selectivity was demonstrated in the presence of ten common oncological co-medications and interferents, where the dual-verification mechanism effectively cross-checked potential matrix anomalies. Finally, the method's sustainability was audited using AGREE (0.69/1.00) and AGREEprep (0.67/1.00) metrics. Overall, this portable EC/SERS approach offers a practical, low-instrumentation, and green alternative for monitoring olaparib in human serum samples.

Cu2+ is an essential trace element for the proper biological function. However, its excess in drinking water poses significant risks to human and animal health. Accordingly, a regulatory limit of 2 µg mL⁻¹ has been established by Spanish and European authorities, highlighting the need for sensitive, rapid, and reliable monitoring strategies. Herein, we report a novel, cost-effective, and fully automated analytical platform based on magnetic micro-solid phase extraction coupled online with capillary zone electrophoresis (MMSPE–CZE), constituting the first fully integrated MMSPE–CZE system for copper determination in drinking water. This approach uniquely enables in-line preconcentration and separation within a single analytical run, significantly enhancing analytical throughput and operational simplicity. The system incorporates a custom-designed magnetic microcolumn packed with (3-aminopropyl)triethoxysilane-functionalized magnetic nanoparticles (MNPs-APTES), seamlessly integrated into the electrophoretic setup. Several extraction and instrumental parameters were selected for optimization using a combination of univariant and multivariant strategies. The proposed method aligned with Green Analytical Chemistry principles and demonstrated to be fast (4 samples h-1), precise (average intraday and interday RSD values 5.2 % and 8.8 %, respectively) and sensitive (EF = 112, LOD = 0.007 µg mL-1, LOQ = 0.03 µg mL-1) under optimum conditions. Importantly, the proposed methodology adheres to Green Analytical Chemistry principles by minimizing reagent consumption, waste generation, and energy demand. Its applicability and robustness were successfully demonstrated through the analysis of bottled water, tap water, and a certified reference material (CRM), with recoveries close to 100% in all cases. Overall, this work establishes a powerful and sustainable alternative to conventional methodologies, combining full automation of MMSPE, high sensitivity, and operational efficiency for routine copper monitoring in drinking water.

Alpelisib, a selective PI3Kα inhibitor, benefits from reliable quantitative measurements to support exposure assessment and dose individualization. Here, we report a portable surface-enhanced Raman spectroscopy (SERS) workflow for rapid urinary screening and quantification of alpelisib using shaped-controlled silver nanoparticles, with silver nanorods selected as the substrate providing the highest SERS response among spherical, cubic, and rod-like morphologies. Key substrate-preparation and instrumental parameters were systematically optimized using a portable 785-nm Raman device, and the analytical figures of merit were thoroughly assessed in urine following a sample clean-up by protein precipitation and liquid–liquid extraction. Under optimized conditions, the diagnostic band at 993 cm⁻¹ was adopted for quantification, and the method provided a linear response from 7.93 to 113.26 µM (R² = 0.9993), with limits of detection and quantification of 2.28 µM and 7.61 µM, respectively. Precision was suitable for a rapid SERS workflow (repeatability and reproducibility RSD ≤ 8.71% and ≤ 8.25%, respectively), with accuracy close to 100% across quality-control levels. A selectivity assessment was performed in urine using an equimolar alpelisib mixture with representative pharmaceutical interferents, and the method reliability was further supported by LC–MS benchmarking, with no statistically significant differences between SERS and LC–MS results for calibration and QC samples at the 95% confidence level (two-tailed t-test). An apparent enhancement factor up to 10³ was estimated for the 993 cm⁻¹ band under the selected conditions, consistent with a predominantly electromagnetic enhancement mechanism with a plausible interfacial chemical contribution. Finally, method sustainability was discussed using the AGREE metric (overall score 0.74/1.00) as a diagnostic tool to identify improvement hotspots. Overall, this portable SERS approach provides a practical, low-instrumentation option for rapid urinary screening and quantification of alpelisib, complementary to LC–MS-based methods for comprehensive bioanalysis. Graphical abstract The alternative text for this image may have been generated using AI.

Melanins are the most abundant skin chromophores. Before being transferred to the target tissues, melanins are synthesized in isolation within melanosomes in melanocytes. Some melanin fragments, however, may leak out of the melanosome. Extramelanosomal melanins interact with nuclear DNA and promote photochemical damage under UV exposure, while DNA–melanin complexes are formed. However, it is unknown how these complexes affect DNA independently of UV, and whether RNA can also form complexes with melanins. Here, we show that DNA–melanin and RNA–melanin complexes are formed under physiological conditions and improve the integrity of the nucleic acids with a high dependency on the melanin form (eumelanin or pheomelanin) involved. After inducing strand shear stress on complexes from chicken follicular melanocytes and comparing them with nucleic acids not bound to melanins, we found that eumelanin protects DNA from strand breaks, while pheomelanin protects RNA. Eumelanin also protects DNA from oxidative damage as revealed by a reduced formation of 8-hydroxy-2′-deoxyguanosine, and both eumelanin and pheomelanin protect RNA from oxidative damage. We provide unprecedented evidence of coexistence of DNA– and RNA–melanin complexes and resolve the long-discussed nature of the interaction as significantly protective. This helps in understanding pigmentation-related diseases and the synthesis of more resistant nucleic acid vectors.

This work describes a cost-effective, label-free electrochemical biosensor for the detection of 8-hydroxy-2′-deoxyguanosine (8OHdG), the most abundant biomarker to evaluate oxidative DNA damage and early cancer risk assessment. The sensor was fabricated by modifying screen-printed carbon electrodes (SPCEs) with a novel composite of magnetic multiwalled carbon nanotubes dispersed in a molecularly imprinted polypyrrole layer (OMMWCNTs@MIPy). This material was adequately characterized, providing enhanced electrocatalytic activity and selective recognition of 8OHdG. Analytical performance was evaluated by differential pulse voltammetry (DPV) after systematic optimization of synthesis and measurement parameters. The proposed method exhibited suitable sensitivity (LOD = 0.28 µM), and excellent repeatability (average intraday RSD 2.7%, and interday RSD 5.0%). High selectivity was also confirmed, with no interference from coexisting species in real samples. The device remained stable for at least 50 measurements and after three months of storage. Validation in spiked biological matrices yielded satisfactory recovery values close to 100% through external calibration. These results demonstrate that the proposed biosensor is a robust, sustainable, low-cost, and portable alternative to conventional immunoassays, suitable for sensitive and real-time monitoring of 8OHdG in nucleic acid samples.