How To Track Blood Flow In Tiny Vessels

Scientists have designed gold nanoparticles, no bigger than 100 nanometres, which can be coated and used to track blood flow in the smallest blood vessels in the body. By improving our understanding of blood flow in vivo the nanoprobes represent an opportunity to help in the early diagnosis of diseaseLight microscopy is a rapidly evolving field for understanding in vivo systems where high resolution is required. It is particularly crucial for cardiovascular research, where clinical studies are based on ultrasound technologies which inherently have lower resolution and provide limited information.

The ability to monitor blood flow in the sophisticated vascular tree (notably in the smallest elements of the microvasculaturecapillaries) can provide invaluable information to understand disease processes such as thrombosis and vascular inflammation. There are further applications for the improved delivery of therapeutics, such as targeting tumours.

Currently, blood flow in the microvasculature is poorly understood. Nanoscience is uniquely placed to help understand the processes happening in the micron-dimensioned vessels. Designing probes to monitor blood flow is challenging because of the environment; the high protein levels in plasma and the high red blood cell concentrations are detrimental to optical imaging. Conventional techniques rely on staining red blood cells, using organic dyes with short-lived usage due to photobleaching, as the tracking motif. The relatively large size of the red blood cells (7-8 micrometres), which are effectively the probes, limits the resolution in imaging and analysis of flow dynamics of the smallest vessels which are of a similar width. Therefore, to have more detailed resolution and information about the blood flow in the microvasculature, even smaller probes are required.

The key to these iridium-coated nanoparticles lies in both their small size, and in the characteristic luminescent properties. The iridium gives a luminescent signal in the visible spectrum, providing an optical window which can be detected in blood. It is also long-lived compared to organic fluorophores, while the tiny gold particles are shown to be ideal for tracking flow and detect clearly in tissues“, explains Professor Zoe Pikramenou, from the School of Chemistry at  the University of Birmingham.

The findings have been published in the journal Nanomedicine.

Source: https://www.birmingham.ac.uk/

SiO2 Nanoparticles Cause Cardiovascular Disease

Nanoparticles, extremely tiny particles measured in billionths of a meter, are increasingly everywhere, and especially in biomedical products. Their toxicity has been researched in general terms, but now a team of Israeli scientists has for the first time found that exposure nanoparticles> (NPs) of silicon dioxide (SiO2) can play a major role in the development of cardiovascular diseases when the nanoparticles cross tissue and cellular barriers and also find their way into the circulatory system.
heart
Environmental exposure to nanoparticles is becoming unavoidable due to the rapid expansion of nanotechnology,” says the study’s lead author, Prof. Michael Aviram, of the Technion Faculty of Medicine, “This exposure may be especially chronic for those employed in research laboratories and in high tech industry where workers handle, manufacture, use and dispose of nanoparticles. Products that use silica-based nanoparticles for biomedical uses, such as various chips, drug or gene delivery and tracking, imaging, ultrasound therapy, and diagnostics, may also pose an increased cardiovascular risk for consumers as well.”

The study has been published in the December 2014 issue of Environmental Toxicology.
The research team was comprised of scientists from the Technion Rappaport Faculty of Medicine, Rambam Medical Center, and the Center of Excellence in Exposure Science and Environmental Health (TCEEH).
Source: http://www.ats.org/

Nano Pacemaker To Extend Cardiac Patients Life

A new type of pacemaker develped by a research team from the University of Bath and the Univerity of Bristol – U.K. – could revolutionise the lives of millions people who live with heart failure in the world. The British Heart Foundation (BHF) is awarding funding to researchers developing a new type of heart pacemaker that modulates its pulses to match breathing rates. Currently, the pulses from pacemakers are set at a constant rate when fitted which doesn’t replicate the natural beating of the human heart. The normal healthy variation in heart rate during breathing is lost in cardiovascular disease and is an indicator for sleep apnoea, cardiac arrhythmia, hypertension, heart failure and sudden cardiac death.
The device works by saving the heart energy, improving its pumping efficiency and enhancing blood flow to the heart muscle itself. Pre-clinical trials suggest the device gives a 25 per cent increase in the pumping ability, which is expected to extend the life of patients with heart failure.


This is a multidisciplinary project with strong translational value. By combining fundamental science and nanotechnology we will be able to deliver a unique treatment for heart failure which is not currently addressed by mainstream cardiac rhythm management devices,” explains Dr Alain Nogaret, Senior Lecturer in Physics at the University of Bath.
One aim of the project is to miniaturise the pacemaker device to the size of a postage stamp and to develop an implant that could be used in humans within five years.
The findings of the research have been published recently in the Journal of Neuroscience Methods.

Source: http://www.bath.ac.uk/

How To Map Your Blood System

A new method allows calcified and constricted blood vessels to be visualized with micrometer (one thousandth of a millimeter) precision, and can be used to design containers for targeted drug delivery. Within the project “NO-stress”, materials scientists from the Medical Faculty of the University of Basel combined cutting-edge-imaging techniques to visualize and quantify the constrictions caused by atherosclerosis. Cardiovascular diseases, including atherosclerosis, are associated with plaque formation and the most prevalent cause of death worldwide. Unlike vessels and other soft tissues, the plaque formed provides strong contrast in X-rays, as known from bone. So far, it has therefore been difficult or even impossible to identify soft tissues in the direct neighborhood of calcifications using X-rays.

A team of researchers from laboratories in three European countries, led by Bert Müller (Biomaterials Science Center at University of Basel), has developed a protocol that is based on the combination of hard X-ray tomography and established histology methods, to visualize the vessels constricted by atherosclerosis.

The data about the morphology of the constricted vessels is used to simulate blood flow and determine related shear stresses. The shear stress is significantly enhanced at the constrictions and forms the basis for the development of specialized nano-containers for the targeted and local delivery of vasodilation drugs

Source: http://unibas.ch/

Mimic ‘Good Cholesterol’ To Heal Cardiovascular

A new type of “good cholesterol,” made in the lab, could one day deliver drugs to where they are needed in the body to treat disease or be used in medical imaging, according to scientists. Their report on the high-density lipoprotein (HDL) mimic, which is easy to make in large amounts, appears in the journal ACS Nano.

Zahi A. Fayad, Robert Langer, YongTae (Tony) Kim, Francois Fay, Willem Mulder and colleagues explain that HDL is a natural nanoparticle that carries cholesterol throughout the body. Because it acts like a scavenger, collecting cholesterol and taking it to the liver for breakdown, HDL has emerged from being simply a marker for cardiovascular disease — the number one killer of men and women in America — to being a therapeutic agent. Clinical trials are testing its potential to combat atherosclerosis, the build-up of plaques in blood vessels that can lead to heart attacks or strokes. Scientists are also exploring new ways to use it for drug delivery. Fayad and Langer’s groups devised a new and improved method for making HDL-like particles.
Lipoprotein
High-density lipoprotein (HDL) is a natural nanoparticle that transports peripheral cholesterol to the liver. Reconstituted high-density lipoprotein (rHDL) exhibits antiatherothrombotic properties and is being considered as a natural treatment for cardiovascular diseases
The scientists showed that microfluidics — the same technology that enabled the invention of inkjet printers — allowed them to make material called µHDL that looks and acts like HDL in a single, rapid step. Not only does this material offer a possible, easy new way to treat cardiovascular disease, but the researchers also attached drug compounds, as well as dyes and nanocrystals used in medical imaging (such as those used for MRIs and CT scans), to the particles.
Source: http://pubs.acs.org/
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