This study presents the design and development of an ultrasonic sensor as a fundamental tool for characterizing the properties of fluids and biofluids. The analysis primarily focuses on measuring the electrical parameters of the system, which correlate with the density and viscosity of the solutions, in sample volumes of microliters and with high temporal resolution (up to 1 data point per second). The use of this sensor allows the fast and non-destructive evaluation of the viscosity and density of fluids deposited on its free surface. The measurements are based on obtaining the impedance versus frequency curve and the phase difference curve (between current and voltage) versus frequency. In this way, characteristic parameters of the transducer, such as the resonance frequency, phase, minimum impedance, and the quality factor of the resonant system, can characterize variations in density and viscosity in the fluid under study. The results obtained revealed the sensor’s ability to identify two parameters sensitive to viscosity and two parameters sensitive to density. As a proof of concept, the unfolding of the bovine albumin protein was studied, resulting in a curve that reflects its unfolding kinetics in the presence of urea.

Silver ions (Ag+) are known to interact with DNA through nonspecific and specific mechanisms, inducing conformational and mechanical changes in the double helix. In this study, we investigate how varying Ag+ concentrations affect the mechanical properties of DNA, in particular, contour length, persistence length, end-to-end distance, and area of occupation, using atomic force microscopy. At low Ag+ concentrations, we observe localized stiffening and shortening of DNA molecules, which we attribute to the formation of monoadducts and biadducts with specific DNA bases. These interactions promote the emergence of secondary structures that contribute to DNA compaction and a reduction in contour length. At intermediate concentrations, accumulation of torsional stress and the formation of multiple metal-mediated contacts lead to a global conformational collapse, as evidenced by a significant decrease in the effective persistence length. At the highest Ag+ concentration tested (1.5 mM), the uniform distribution of molecular area suggests a widespread structural collapse of DNA. These findings support previous reports of Ag+-induced DNA condensation and reveal a progressive structural transition from extended to globular conformations. The observed behavior provides insights into the biophysical consequences of metal–DNA interactions and may have implications for understanding the molecular basis of the antimicrobial activity of silver ions.

We investigated the interaction between the monocationic aromatic drug propranolol (PPL) and double-stranded DNA (dsDNA) to elucidate how small molecules c

El desarrollo de sistemas rápidos y precisos para la caracterización de biofluidos es cada vez más relevante debido a la complejidad de sus cinéticas y las dinámicas moleculares que ocurren en su interior. Estas interacciones reflejan los cambios estructurales de los biopolímeros al interactuar con otros agentes. Monitorear estos procesos es fundamental para comprender los mecanismos subyacentes de dichas interacciones. Este estudio presenta una solución de software de código abierto diseñada para controlar y monitorear transductores ultrasónicos para la medición en tiempo real de las propiedades de los biofluidos. El software, desarrollado en Python, se integra con hardware personalizado para realizar barridos de frecuencia 650 % más rápidos que los dispositivos comerciales como el LCR-8101G, reduciendo el tiempo de adquisición de datos a 0.169 segundos por muestra. Esta mejora significativa permite estudios cinéticos detallados de biofluidos, como se demuestra en la caracterización de las interacciones entre Albúmina Bovina (BSA) y urea. El diseño modular del sistema permite la fácil integración de sensores adicionales, como sondas de temperatura, que pueden mejorar el proceso de caracterización al proporcionar datos más completos. Además, la compatibilidad del software con modelos de aprendizaje automático abre la posibilidad de capacidades predictivas avanzadas lo que, potencialmente, permite la identificación en tiempo real de las propiedades de los biofluidos basándose en la respuesta ultrasónica. Los resultados de este estudio, en términos de tiempo de ejecución, validan la eficacia del software para acelerar la adquisición de datos sin comprometer la sensibilidad, convirtiéndolo en una herramienta valiosa para los investigadores que estudian fenómenos evolutivos en biofluidos. El trabajo futuro se centrará en expandir aún más las capacidades del sistema, estandarizar el software para una adopción más amplia y explorar su aplicación en diversos escenarios experimentales con el propósito de mejorar la comprensión del comportamiento de los biofluidos bajo diferentes condiciones.

Introduction: A significant portion of the population still lacks access to drinking water and relies on non-conventional sources such as wells and springs. In these cases, information on water quality and availability is difficult and expensive to obtain. The solutions available in the local market do not offer equitable access to tools that effectively address these needs.Objective: This work describes the development of an autonomous system composed of hardware and software, designed to monitor in real time the physical-chemical parameters of water, as well as to visualize and interpret the data in a way that is accessible and understandable for the community.Methodology: An IoT-WQMS-based device is presented, which uses five sensors to measure in real time key water parameters, such as pH, conductivity, turbidity, flow rate, temperature and humidity. The data is transmitted via GSM signal using the MQTT protocol, and is processed and visualized through easy-to-use software, designed to be accessible to the community.Results: The results include the graphical interface and visualization of water quality data in a laboratory prototype, both instantaneously and averaged over defined time intervals.Conclusions: The IoT-WQMS system presents advantages in terms of cost and accessibility for obtaining and interpreting water quality data in low-flow sources, in a laboratory environment. Future challenges include the transition to renewable energy and the integration of additional communication protocols, such as LoRaWAN.