Acoustophoretic trapping of particles by bubbles in microfluidics

We present in this paper a simple method to produce strategic acoustic particle capture sites in microfluidic channels in a controlled way. Air bubbles are intermittently injected into a micro-capillary with rectangular cross section during a flow motion of liquid suspensions containing micron-sized particles or particles to create bubble-defined “micro-gaps” with size close to 200 µm and spheroidal geometry. The establishment of a 3D standing acoustic wave inside the capillary at a frequency close to 1 MHz produces different radiation forces on solid particles and bubbles, and acoustic streaming around the bubble. While the sample flows, part of the particles collect along the acoustic pressure node established near the central axis and continue circulating aligned through the capillary until reaching the end, where are released enriched. Meanwhile, the bubble travels very fast toward positions of maximum pressure amplitude beside the channel wall, driven by Bjerkness forces, and attach to it, remaining immovable during the acoustic actuation. Some particles adhere to its membrane trapped by the acoustic streaming generated around the oscillating bubble. Changes of frequency were applied to analyze the influence of this parameter on the bubble dynamics, which shows a complete stability once attached to the channel wall. Only increasing the flow motion induces the bubble displacements. Once reached the open air at the end of the capillary, the bubble disappears releasing the trapped particles separated from their initial host suspension with a purity degree. The device presents a very simple geometry and a low-cost fabrication.This work is financed by the Spanish National Plan project PID2021-128985OB-I00 funded by the Spanish Ministery of Science and Innovation MICINN and CSIC-Intramural project

Low-intensity continuous ultrasound to inhibit cancer cell migration

In recent years, it has been verified that collective cell migration is a fundamental step in tumor spreading and metastatic processes. In this paper, we demonstrate for the first time how low-intensity ultrasound produces long-term inhibition of collective migration of epithelial cancer cells in wound healing processes. In particular, we show how pancreatic tumor cells, PANC-1, grown as monolayers in vitro respond to these waves at frequencies close to 1 MHz and low intensities (< 100 mW cm(-2)) for 48-72 h of culture after some minutes of a single ultrasound irradiation. This new strategy opens a new line of action to block the spread of malignant cells in cancer processes. Despite relevant spatial variations of the acoustic pressure amplitude induced in the assay, the cells behave as a whole, showing a collective dynamic response to acoustic performance. Experiments carried out with samples without previous starving showed remarkable effects of the LICUs from the first hours of culture, more prominent than those with experiments with monolayers subjected to fasting prior to the experiments. This new strategy to control cell migration demonstrating the effectiveness of LICUS on not starved cells opens a new line of action to study effects of in vivo ultrasonic actuation on tumor tissues with malignant cells. This is a proof-of-concept study to demonstrate the physical effects of ultrasound stimulation on tumor cell migration. An in-depth biological study of the effects of ultrasounds and underlying biological mechanisms is on-going but out of the scope of this article.This work is financed by the Spanish National Plan projects PID 2021-128985OB-I00: "New Non-invasive technology to inhibit growth of solid tumors by low intensity ultrasounds", DPI 2017-90147-R and intramural research project IRYCIS (2018/0240)

SALMANTICOR study. Rationale and design of a population-based study to identify structural heart disease abnormalities: a spatial and machine learning analysis

[EN]Introduction: This study aims to obtain data on the prevalence and incidence of structural heart disease in a population setting and, to analyse and present those data on the application of spatial and machine learning methods that, although known to geography and statistics, need to become used for healthcare research and for political commitment to obtain resources and support effective public health programme implementation. Methods and analysis: We will perform a cross-sectional survey of randomly selected residents of Salamanca (Spain). 2400 individuals stratified by age and sex and by place of residence (rural and urban) will be studied. The variables to analyse will be obtained from the clinical history, different surveys including social status, Mediterranean diet, functional capacity, ECG, echocardiogram, VASERA and biochemical as well as genetic analysis. Ethics and dissemination: The study has been approved by the ethical committee of the healthcare community. All study participants will sign an informed consent for participation in the study. The results of this study will allow the understanding of the relationship between the different influencing factors and their relative importance weights in the development of structural heart disease

Acoustophoretic particle manipulation in hybrid solid/gel resonators

10 páginas, 4 figuras, 1 tablaThis study presents a proof of concept to demonstrate the ability of ultrasounds to perform acoustophoretic processes in hybrid millifluidic resonators that include channels laterally embedded in extremely soft media with physical properties close to those of liquids. In our experiments, particles are driven by acoustic radiation forces toward hydrodynamic/acoustic equilibrium positions in a similar way to that produced in conventional microfluidic resonators with solid structures; 20 um-sized polystyrene beads immersed in deionized water flow channelized throughout an aqueous-based gel between an inlet and outlet in a resonant chamber while being exposed to ultrasounds at a frequency of 1.54 MHz. The liquid channel formed presents irregular walls and variable geometry defined by the sample injection pressure. Particles collect rapidly along a central line equidistant from the walls, regardless of whether they are parallel or not, as observed for different channel geometries and cross-sectional dimensions. Only when the flow stops, the particles collect in acoustic pressure nodes established with the 2D spatial distribution. These results break the paradigm of solid structures as essential physical elements to support acoustophoresis, demonstrating the ability to produce these processes in media without a consolidated structure. It opens a door to bioprinting applications.This research was supported and funded by the National Research Project DPI2017-90147-R of Spain and by the National Research Council of Spain CSIC through project i-COOPA20348. The trap device belonging to Bazou was used for the experiments

Spontaneous Variation of Ventriculo-Atrial Interval after Tachycardia Induction: Determinants and Usefulness in the Diagnosis of Supraventricular Tachycardias with Long Ventriculoatrial Interval

Background: Determining the mechanism of supraventricular tachycardias with prolongedP ventriculoatrial (VA) intervals is sometimes a challenge. Our objective is to analyse the determinants, time course and diagnostic accuracy (atypical atrioventricular nodal reentrant tachycardias [AVNRT] versus orthodromic reentrant tachycardias through an accessory pathway [ORT]) of spontaneous VA intervals variation in patients with narrow QRS tachycardias and prolonged VA. Methods: A total of 156 induced tachycardias were studied (44 with atypical AVNRT and 112 with ORT). Two sets of 10 measurements were performed for each patient—after tachycardia induction and one minute later. VA and VV intervals were determined. Results: The difference between the longest and the shortest VA interval (Dif-VA) correlates significantly with the diagnosis of atypical AVNRT (C coefficient = 0.95 and 0.85 after induction and at one minute, respectively; p p < 0.001 for both) but not in ORTs. Conclusions: The analysis of VA interval variability after induction and one minute later correctly discriminates atypical AVNRT from ORT in almost all cases

Update on ischemic heart disease and critical care cardiology

3.342 JCR (2013) Q2, 40/125 Cardiac & cardiovascular system

Outcome Analysis in Elective Electrical Cardioversion of Atrial Fibrillation Patients: Development and Validation of a Machine Learning Prognostic Model.

Background: The integrated approach to electrical cardioversion (EC) in atrial fibrillation (AF) is complex; candidates can resolve spontaneously while waiting for EC, and post-cardioversion recurrence is high. Thus, it is especially interesting to avoid the programming of EC in patients who would restore sinus rhythm (SR) spontaneously or present early recurrence. We have analyzed the whole elective EC of the AF process using machine-learning (ML) in order to enable a more realistic and detailed simulation of the patient flow for decision making purposes. Methods: The dataset consisted of electronic health records (EHRs) from 429 consecutive AF patients referred for EC. For analysis of the patient outcome, we considered five pathways according to restoring and maintaining SR: (i) spontaneous SR restoration, (ii) pharmacologic-cardioversion, (iii) direct-current cardioversion, (iv) 6-month AF recurrence, and (v) 6-month rhythm control. We applied ML classifiers for predicting outcomes at each pathway and compared them with the CHA2DS2-VASc and HATCH scores. Results: With the exception of pathway (iii), all ML models achieved improvements in comparison with CHA2DS2-VASc or HATCH scores (

La consulta telemática para el cardiólogo clínico en tiempos de la COVID-19: presente y futuro. Documento de consenso de la Sociedad Española de Cardiología.

The coronavirus disease 2019 (COVID-19) pandemic has changed how we view our consultations. To reduce the risk of spread in the most vulnerable patients (those with heart disease) and health personnel, most face-to-face consultations have been replaced by telemedicine consultations. Although this change has been rapidly introduced, it will most likely become a permanent feature of clinical practice. Nevertheless, there remain serious doubts about organizational and legal issues, as well as the possibilities for improvement etc. In this consensus document of the Spanish Society of Cardiology, we attempt to provide some keys to improve the quality of care in this new way of working, reviewing the most frequent heart diseases attended in the cardiology outpatient clinic and proposing some minimal conditions for this health care process. These heart diseases are ischemic heart disease, heart failure, and arrhythmias. In these 3 scenarios, we attempt to clarify the basic issues that must be checked during the telephone interview, describe the patients who should attend in person, and identify the criteria to refer patients for follow-up in primary care. This document also describes some improvements that can be introduced in telemedicine consultations to improve patient care