Many bioengineering laboratories are actively researching how to produce synthetic or natural scaffolds seeded with human mesenchymal stem cells (MSCs). The aim of this work is to implant the structures into diseased or damaged sites and encourage healing by introducing a healthy pluripotent cell population on an anatomically correct form. Current research is particularly focused on including small molecules within the scaffold in order to steer MSCs to differentiate to a desired cell type. The number of possible combinations of scaffold material, biomolecular cues, and fabrication methods is vast and holds a lot of therapeutic potential.
Percutaneous transluminal angioplasty is a common procedure to clear blocked arteries. This is often accomplished by inserting a balloon catheter. At the site of the blockage the balloon is inflated and pushes against the arterial wall for a few minutes before being removed. In many cases this is sufficient to open the artery. However, the balloon often damages the arterial wall and it is important that the endothelium repairs itself quickly in order to prevent blood clots and excessive proliferation of smooth muscle (hyperplasia). A common method to stimulate endothelial growth is to introduce vascular endothelial growth factor (VEGF) locally or through the bloodstream. Unfortunately, the half-life of VEGF is short and the large amount needed for efficacy is expensive. This motivated researchers from the Harbin Medical University in the Heilongjiang Province of China to develop a way to locally deliver the VEGF gene to the site of a ballon-injured artery.
The goal of the series of posts from the last weeks was to review the state-of-the-art of magnetic beads coatings. The contributors have reviewed the classical surfaces, but also the new approaches to improve and simplify the process. Last but not least, the physical aspects of the magnetic beads and the separation process were discussed, as they have a critical impact on the success of the coating process.
Researchers at the Shanghai Key Laboratory of Tuberculosis have improved upon a tool for detecting mycobacterium tuberculosis (MTB) in human samples of deep-lung mucus. The tool combines magnetic, fluorescent, and immunologic sorting techniques to increase test sensitivity and portability. Tuberculosis-specific antibodies and proteins are conjugated to the surfaces of quantum dots (QDs) and magnetic microspheres (MMSs). In this functionalized state the quantum dots and microspheres can freely bind to the mycobacterium. At optimal concentrations, along with sufficient incubation time, the QDs and MMSs each serve as a slice of bread in a QD-MTP-MMS sandwich. The sample is magnetically sorted to collect the MMSs before quantifying the amount of QD fluorescence with a spectrofluorometer.
Bioengineers at the University of California, Los Angeles have developed a new technique for patterning magnetic material onto polydimethyl-siloxane (PDMS), a flexible polymer known as an elastomer. The resulting product has promising biotechnical applications. Its flexibility allows it to conform to many different shapes, and its magnetic field can be tuned by the application of an external magnet.
Coating your magnetic beads with biomarkers is the most critical step during the development and production of Chemiluminescence Immunoassays (CLIA). Attaching the antibody (or any other protein) to the bead’s surface requires incubating both materials together, using the right buffer and temperature, gently mix and homogenize the suspension. Once the process is completed, it is necessary to separate the solid phase (the magnetic beads with the attached biomolecule) from the rest of the suspension and, once washed, re-suspend the reagent in a new buffer for avoid biomarker reaction and beads aggregation.
Although magnetic particles have proven exceedingly useful in nanotherapy protocols, applications making use of external magnets have been limited to surface or shallow targets. The ability to use external magnets to focus on deeper targets has remained a challenge. To this end, a collaboration between researchers from the University of Maryland and Weinberg Medical Physics LLC has devised a way to use pulsed magnetic fields to direct particles to hard-to-reach targets.
During protein (or other kind of molecules) coating onto magnetic particles, there are two main parameters that govern the success of the process: the physical and chemical properties of the protein itself and the magnetic particle dispersions. For this reason, the correct selection of these components is the key for an excellent coating. In this article the importance of physical properties of magnetic dispersions is discussed.
Core/shell nanoparticles offer an additional degree of flexibility to nanoparticle-based applications. Comprised of an inorganic core and one or more shell layers, such particles enable a wider range of physical properties than would be possible for each of the component materials taken separately. In the case of bi-magnetic core/shell nanoparticles, the constituent materials exhibit distinct magnetic properties, yielding an extra layer of customization to the particle, based on the exchange interaction between the components.
Magnetic beads are available with a large variety of surface coatings. One of the coatings are the Tosyl activated beads. This post is describing the handling and advantages of the use of Tosyl activated magnetic beads in chemiluminescent immunoassays.
