Controlled Electrospray Generation of Non-Spherical Aqueous Microparticles

Symposium SM5—Aqueous Cytomimetic Materials - Symposium SM5.1: Hydrodynamics of Aqueous Two-Phase Systems (ATPS) Droplets - paper no. SM5.1.05Production of aqueous polymeric microparticles has attracted increasing interest because they benefit a variety of new biomedical applications such as cell encapsulation. Here we present a technique based on the application of electrospray to generate aqueous non-spherical microparticles using sodium alginate as emulsion phase and calcium chloride for continues phase. This approach allows the formation of calcium alginate microbeads with tunable sizes and shapes. We use a high voltage power supply to form the electric field, we apply a charge to the alginate solution that flows through a glass capillary with a tapered tip, and we ground a metallic ring that is positioned beneath the capillary tip. We investigate the effects of changing various parameters such as voltage, flow rate, capillary tip size, reagent concentration, and the distance from the capillary tip to the free interface of the calcium chloride bath, and discover parameter spaces that yield a variety of different shape and size particles. This technique of aqueous microparticles may have applications in drug delivery, enzyme immobilization, cell encapsulation and drug screening and further investigation of this technique can lead to a simple but high throughput method for generation of three-dimensional culture system in cancer studies

Effect of different ECG leads on estimated R–R intervals and heart rate variability parameters

Abstract Heart rate and heart rate variability parameters provide important information on sympathetic and parasympathetic branches of autonomous nervous system. These parameters are usually extracted from electrocardiograms often measured between two electrodes and called an ECG lead. Besides systems intended only for heart rate measurement, ECG measurement devices employ several well-known lead systems including the standard 12-lead system, EASI lead system and Mason-Likar systems. Therefore, the first step is to select the appropriate lead for heart rate variability analysis. The appropriate electrode locations for single-lead measurement systems or the preferred measurement lead in multi-lead measurement are choices that the user needs to make when the heart rate variability is of interest. However, it has not been addressed in the literature, if the lead selection has an effect on the obtained HRV parameters. In this work, we characterized the amount of deviation of heart rate and heart rate variability parameters extracted from nine ECG leads, six from EASI leads and three modified limb leads. The results showed a deviation of 2.04, 2.88, 2.06 and 3.45 ms in SDNN, rMSSD, SD1 and SD2, respectively. A relative difference up to 10% was observed in HRV parameters for single signal frames. Additionally, the discrimination of the R-peaks by amplitudes was evaluated. The A-S lead appeared to have the best performance in all the tests

Electrode comparison for textile-integrated electrocardiogram and impedance pneumography measurement

Wearable electronics is a quickly broadening category in sports, wellbeing and entertainment products. Also, fully textile-integrated electronics is used increasingly to improve user experience. Medical industry is interested in exploiting, especially the latter sub-category of wearable electronics in long-term home care. In this study, we report a textile-integrated electrocardiography (ECG) and impedance pneumography (IP) measurement system. The performance of the system is evaluated by comparing the measurement accuracy for heart rate and respiration rate obtained with different electrode types and different measurement methods. Three electrode types: disposable, textile, and printed electrodes, are investigated and both, bipolar and tetrapolar measurement methods are compared by using a modified commercial evaluation board. Disposable electrodes provide the least noisy signal and the most stable results. However, the skin irritation caused by these electrodes prevents their use in long-term monitoring. The textile and printed electrodes did not seem to cause similar skin irritation. From the two measuring techniques, tetrapolar measuring method had higher noise levels, but heart rate and breathing were estimated with better accuracy compared to bipolar measuring method.submittedVersionPeer reviewe

Unobtrusive, low‐cost out‐of‐hospital, and in‐hospital measurement and monitoring system

Abstract Continuous monitoring of vital signs can be a life‐saving matter for different patient groups. The development is going toward more intelligent and unobtrusive systems to improve the usability of body‐worn monitoring devices. Body‐worn devices can be skin‐conformable, patch‐type monitoring systems that are comfortable to use even for prolonged periods of time. Herein, an intelligent and wearable, out‐of‐hospital, and in‐hospital four‐electrode electrocardiography (ECG) and respiration measurement and monitoring system is proposed. The system consists of a conformable screen‐printed disposable patch, a measurement unit, gateway unit, and cloud‐based analysis tools with reconfigurable signal processing pipelines. The performance of the ECG patch and the measurement unit was tested with cardiac patients and compared with a Holter monitoring device and discrete, single‐site electrodes