Ada Raucci

Flexible electrochemical sensors have gained increasing attention due to their applicability in real-world analytical scenarios involving complex and non-planar surfaces. The influence of mechanical deformation on sensor performance has been previously reported; however, these effects are often evaluated under non-standardized conditions or after mechanical stress is applied, limiting a systematic and comparative understanding of sensor behavior under realistic operating conditions. In this context, 3D printing offers a versatile and accessible approach for fabricating customized platforms capable of applying controlled and reproducible mechanical deformation during electrochemical measurements. Herein, we present a strategy to evaluate the effect of mechanical stress on screen-printed electrochemical sensors (SPEs) fabricated on polyester, office paper, and Ecovio® biopolymeric substrates. While all sensors exhibited similar electrochemical behavior under flat conditions, significant differences emerged under bending, with substrate-dependent reductions in current and variations in signal stability. These effects were more pronounced for paper-based electrodes, whereas Ecovio-based devices showed greater robustness to deformation. The findings highlight the critical role of substrate mechanical properties in determining sensor performance under realistic operating conditions. The results show that controlled deformation reveals substrate-dependent performance differences not observable under flat conditions, enabling more consistent material evaluation. This versatile 3D-printed approach can be extended beyond electrochemical sensors, enabling reproducible testing and guided selection of flexible devices for optical and colorimetric applications.

This research presents an innovative all-in-one 3D-printed electrochemical biosensor for noninvasive detection of uric acid in saliva. Uric acid is a key biomarker for monitoring disorders such as gout and kidney disease as well as assessing the progression of metabolic conditions. The 3D-printed platform integrates a microwell, saliva collection module, and a three-electrode system, including carbon black and Prussian-blue-modified electrodes with immobilized uricase, into a single compact device, streamlining the sampling-to-detection workflow. Initial optimization using screen-printed electrodes on polyester films with differential pulse voltammetry established baseline performance, while the fully integrated 3D-printed system, with the incorporation of uricase, achieved detection limits of 0.09 μM in phosphate-buffered saline and 0.1 μM in 20% diluted saliva. Comparative analysis with high-performance liquid chromatography confirmed the accuracy and reliability of the measurements. By combining nanomaterial-enhanced electrodes, enzymatic recognition, and additive manufacturing, this platform offers a portable, user-friendly, and low-cost solution for point-of-care uric acid monitoring. The integrated design minimizes sample handling, prevents contamination, and enables hygienic, noninvasive collection. This approach facilitates rapid diagnostic testing and real-time health monitoring, providing actionable information for personalized patient care. Overall, the fully 3D-printed biosensing system represents a significant advance in electrochemical biosensors, demonstrating the potential to improve the clinical management of uric acid-related conditions while enabling scalable, accessible, and point-of-care diagnostics.

Locked nucleic acids (LNAs) are chemically modified oligonucleotides widely used in gene silencing and precision oncology, yet their clinical translation is limited by the absence of simple, rapid assays to quantify them directly in biological fluids for dose optimization and timely therapeutic feedback. Here, we report a paper-based electrochemical biosensor for the direct detection of antisense LNA oligonucleotides using LNA-anti-miR-155 as a clinically relevant model. The platform employs a methylene blue-labeled RNA probe that mimics the native miRNA target and yield a signal-off voltammetric response upon hybridization. The disposable, gold nanoparticle-modified paper electrodes support picomolar detection limits, high reproducibility, and reliable performance in undiluted human plasma without sample pretreatment. By combining portability, low cost, and rapid analysis in a single-use format, this biosensor advances point-of-care monitoring of LNA-based therapeutics and provides a versatile blueprint for future personalized treatment platforms targeting antisense oligonucleotides.

Locked nucleic acids (LNAs) are chemically modified oligonucleotides that play a central role in modern gene silencing strategies, particularly in precision oncology. However, their clinical application is limited by the absence of simple and rapid methods to monitor their concentration in biological fluids, which is essential for optimizing dosage and enabling real-time therapeutic feedback. In this study, we report the first electrochemical biosensor specifically designed for the detection of antisense LNA oligonucleotides. The platform employs a methylene blue-labelled probe that mimics the natural miRNA target, producing a clear signal-off response upon hybridization with LNA-anti-miR-155. The biosensor demonstrates excellent performance and achieves a detection limit in the picomole range, even in undiluted human plasma. Combining high sensitivity, rapid analysis, and direct operation in complex matrices, this device represents a concrete step toward point-of-care monitoring of LNA-based therapies, paving the way for truly personalized treatment regimens.

Excessive reactive oxygen species (ROS) under pathophysiological conditions primarily initiate oxidative stress, which contributes to the development of atherosclerosis and other cardiovascular diseases. Hydrogen peroxide (H2O2) is a crucial oxidative stress biomarker due to its stability and significant role in signaling pathways linked to cellular damage. Hence, H₂O₂ detection is crucial for early disease diagnosis, understanding oxidative stress mechanisms, and therapeutic intervention, especially in cardiac health, where oxidative damage is significant. However, efficient, highly selective & sensitive, quick, and accurate H₂O₂ detection remains a challenge in the protracted battle against oxidative stress-related diseases. The study presents a fast, portable, low-cost, and versatile oxidative stress detection platform using a rGO-Co₃O₄-Pt nanocomposites electrochemical sensor platform, which can be remotely controlled. The sensors offer ultrasensitive, versatile cardiac stress monitoring, with H2O2 detection up to 2.50 µM, low LOD (0.16 µM) and LOQ (0.50 µM), with anti-interference capability and biocompatibility, indicating the possibility of real-sample analysis. Furthermore, we conducted studies on doxorubicin (DOX)-induced cardiotoxicity in vitro (HL-1 cell lines) and in vivo (adult C57BL/6J mice model). The study indicates that the rGO-Co₃O₄-Pt nanocomposite electrochemical sensor platform can efficiently and accurately detect diseases. This work provides direct experimental evidence of ROS detection and offers an efficient electronic platform that is significantly lighter, cheaper, and smaller than alternatives.

Printed electrochemical strips are increasingly used in nucleic acid diagnostics due to their affordability portability, compactness, and ease of use. To respond to traditional electrochemical methods that require complex immobilization protocols, in this study, we introduce a simplified platform that combines a cost-effective electrode printed on a polyester substrate with a hybridization chain reaction (HCR) for DNA signal amplification. Unlike prior approaches that rely on nanomaterials or intricate modifications, our method places the target sequence and hairpins directly on the electrode surface, reducing both cost and preparation time while maintaining efficient signal amplification. Using DNA modified with methylene blue (MB) as a redox mediator, the system generates a "signal-off" response by suppressing electron transfer when MB intercalates into the DNA polymers formed by HCR. This approach eliminates the need for complex surface functionalization, enhancing ease of fabrication and consistency. Targeting miRNA-21, a known cancer biomarker, the sensor achieves picomolar sensitivity in both buffer and diluted human serum. This platform offers a cost-effective, sensitive, and portable solution for point-of-care diagnostics and real-time miRNA monitoring in clinical settings.

The dissemination of sensors is key to realizing a sustainable, ‘intelligent’ world, where everyday objects and environments are equipped with sensing capabilities to advance the sustainability and quality of our lives—e.g. via smart homes, smart cities, smart healthcare, smart logistics, Industry 4.0, and precision agriculture. The realization of the full potential of these applications critically depends on the availability of easy-to-make, low-cost sensor technologies. Sensors based on printable electronic materials offer the ideal platform: they can be fabricated through simple methods (e.g. printing and coating) and are compatible with high-throughput roll-to-roll processing. Moreover, printable electronic materials often allow the fabrication of sensors on flexible/stretchable/biodegradable substrates, thereby enabling the deployment of sensors in unconventional settings. Fulfilling the promise of printable electronic materials for sensing will require materials and device innovations to enhance their ability to transduce external stimuli—light, ionizing radiation, pressure, strain, force, temperature, gas, vapours, humidity, and other chemical and biological analytes. This Roadmap brings together the viewpoints of experts in various printable sensing materials—and devices thereof—to provide insights into the status and outlook of the field. Alongside recent materials and device innovations, the roadmap discusses the key outstanding challenges pertaining to each printable sensing technology. Finally, the Roadmap points to promising directions to overcome these challenges and thus enable ubiquitous sensing for a sustainable, ‘intelligent’ world.