Effect of Bubbling on the Potential of Reference Electrode

The method for the examination of gas/water interface electrokinetic behavior is developed. "Bubbling potential", i.e. the difference in the potential of the indicator electrode in the absence and presence of gas bubbles was measured. The indicator electrode is a reference electrode with the porous plug exposed to gas bubbles. The charged bubble in contact with the porous plug would affect the potential of the indicator electrode. However, electrodes, whose potential depends on the reversible interfacial reaction, would be relaxed due to the interfacial ionic equilibration and their potential will not be affected by the presence of bubbles. Measured Bubbling potentials are directly related to electrokinetic - potentials. The proposed method is fast, accurate and reproducible so that it can be used for the examination of gas/water interfaces in different conditions. The isoelectric point of argon bubbles in the aqueous NaCl solution was obtained as pHiep = 3.9 and pHiep = 3.4 at ionic strength of 10–3 and 10–2 mol dm–3, respectively. (doi: 10.5562/cca2235

Real-time volumetric lipid imaging in vivo by intravascular photoacoustics at 20 frames per second

Lipid deposition can be assessed with combined intravascular photoacoustic/ultrasound (IVPA/US) imaging. To date, the clinical translation of IVPA/US imaging has been stalled by a low imaging speed and catheter complexity. In this paper, we demonstrate imaging of lipid targets in swine coronary arteries in vivo, at a clinically useful frame rate of 20 s−1. We confirmed image contrast for atherosclerotic plaque in human samples ex vivo. The system is on a mobile platform and provides real-time data visualization during acquisition. We achieved an IVPA signal-to-noise ratio of 20 dB. These data show that clinical translation of IVPA is possible in principle

Effect of Bubbling on the Potential of Reference Electrode

The method for the examination of gas/water interface electrokinetic behavior is developed. "Bubbling potential", i.e. the difference in the potential of the indicator electrode in the absence and presence of gas bubbles was measured. The indicator electrode is a reference electrode with the porous plug exposed to gas bubbles. The charged bubble in contact with the porous plug would affect the potential of the indicator electrode. However, electrodes, whose potential depends on the reversible interfacial reaction, would be relaxed due to the interfacial ionic equilibration and their potential will not be affected by the presence of bubbles. Measured Bubbling potentials are directly related to electrokinetic - potentials. The proposed method is fast, accurate and reproducible so that it can be used for the examination of gas/water interfaces in different conditions. The isoelectric point of argon bubbles in the aqueous NaCl solution was obtained as pHiep = 3.9 and pHiep = 3.4 at ionic strength of 10–3 and 10–2 mol dm–3, respectively. (doi: 10.5562/cca2235

An Implantable Artificial Atherosclerotic Plaque as a Novel Approach for Drug Transport Studies on Drug-Eluting Stents

Atherosclerotic arteries are commonly treated using drug-eluting stents (DES). However, it remains unclear whether and how the properties of atherosclerotic plaque affect drug transport in the arterial wall. A limitation of the currently used atherosclerotic animal models to study arterial drug distribution is the unpredictability of plaque size, composition, and location. In the present study, the aim is to create an artificial atherosclerotic plaque—of reproducible and controllable complexity and implantable at specific locations—to enable systematic studies on transport phenomena of drugs in stented atherosclerosis-mimicking arteries. For this purpose, mixtures of relevant lipids at concentrations mimicking atherosclerotic plaque are incorporated in gelatin/alginate hydrogels. Lipid-free (control) and lipid-rich hydrogels (artificial plaque) are created, mounted on DES and successfully implanted in porcine coronary arteries ex-vivo. Matrix-assisted laser desorption ionization mass spectrometry imaging (MALDI-MSI) is used to measure local drug distribution in the arterial wall behind the prepared hydrogels, showing that the lipid-rich hydrogel significantly hampers drug transport as compared to the lipid-free hydrogel. This observation confirms the importance of studying drug transport phenomena in the presence of lipids and of having an experimental model in which lipids and other plaque constituents can be precisely controlled and systematically studied

Visualization 2: Real-time volumetric lipid imaging in vivo by intravascular photoacoustics at 20 frames per second

in vivo IVPA/US pullback recording on a swine coronary artery with artificial plaque Originally published in Biomedical Optics Express on 01 February 2017 (boe-8-2-943

Visualization 2: Real-time volumetric lipid imaging in vivo by intravascular photoacoustics at 20 frames per second

in vivo IVPA/US pullback recording on a swine coronary artery with artificial plaque Originally published in Biomedical Optics Express on 01 February 2017 (boe-8-2-943

Real-time volumetric lipid imaging in vivo by intravascular photoacoustics at 20 frames per second

Lipid deposition can be assessed with combined intravascular photoacoustic/ultrasound (IVPA/US) imaging. To date, the clinical translation of IVPA/US imaging has been stalled by a low imaging speed and catheter complexity. In this paper, we demonstrate imaging of lipid targets in swine coronary arteries in vivo, at a clinically useful frame rate of 20 s−1. We confirmed image contrast for atherosclerotic plaque in human samples ex vivo. The system is on a mobile platform and provides real-time data visualization during acquisition. We achieved an IVPA signal-to-noise ratio of 20 dB. These data show that clinical translation of IVPA is possible in principle