The isolation of circulating tumor cells is essential to diagnostics and metastasis studies. Since these cells are rare compared to the whole cell content of blood, the isolation process poses a challenge. There are several widespread methods of analysis and isolation of circulating tumour cells, from direct analysis of blood by marking tumor cells selectively, to blood processing through flow cytometry and magnetophoresis, that are based on EpCAM expression by tumor cells. However, circulating tumor cells from cancers of non-epithelial origin and cells that go through epithelial to mesenchymal transition do not have EpCAM. Therefore, these approaches have the tendency to lose rare cells.
Sepmag is yet again reaching new audiences by publishing the first of a two-article series about biomagnetic separation.
A team of scientist in Shanghai, China has placed magnetic nanoparticles into the thin-film realm. The group has created a flexible magnetic nanofibrous membrane by combining gelatin dip-coating methods with electrospun silica nanofibers. An external magnet can control the membrane flexion. The membrane also demonstrates selective wettability meaning that it is impervious to oil while easily allowing water to penetrate through.
Magnetic activated cell sorting: Description of the technique
Magnetic activated cell sorting (MACS) is a technique whereby specific cell populations are isolated from solution through the use of superparamagnetic iron-oxide nanoparticles and an external magnet. Describing the nanoparticles as superparamagnetic indicates that they are not intrinsically magnetic, but can become magnetized when influenced by a magnetic field from an external magnet. The nanoparticles are coated with polymers or polysaccharides and functional moieties to make them biocompatible and capable of binding to one cell population of interest. After an incubation period, during which the nanoparticles bind to the cells, an external magnet is applied and the nanoparticles move through the magnetic field gradient to be isolated from the solution. The unwanted cells and contaminants are washed away to produce a pure cell isolate. That cell isolate is often cultured or molecularly analyzed. It is important to avoid contamination, but recent research on splenic cell isolates has discovered that splenic red pulp macrophages are intrinsically superparamagnetic, and are separated out of solution along with the nanoparticle-bound cells.
Many people are not aware that magnetic nanoparticles used in cell separation techniques must be able to aggregate when a magnetic field gradient is applied. If the particles fail to aggregate they remain as single entities and are difficult to separate out of thesolution. An aggregation of magnetic nanoparticles is highly influenced by a magnetic field gradient and can be easily isolated and removed. Therefore, a thermally controlled reversible aggregation system is desirable.
The latest trends and concepts in the In-Vitro Diagnostic (IVD) products market will be presented by leading representatives of Merck Millipore.
Magnetic Activated cell sorting is a technique that uses small paramagnetic iron-oxide particles to separate cells or nucleotides from solution. These particles are often called magnetic nanoparticles due to their small sizes ranging from less than 100 nm to 5 μm. The technique requires and external magnet to create a magnetic field gradient. The magnetic particles are chemically altered to be biologically compatible and to specifically bind to a variety of different cell types. The cells of interest can be bound by the particles and isolated from solution (positive selection) or the unwanted cells can be bound and removed from solution (negative selection).
The chemiluminescent immunoassay is a technique used for disease diagnosis, drug development, chemical reaction monitoring, and many other applications. The protein or antigen to be identified in these assays is referred to as an analyte. As the name suggests, the assay works by measuring the light produced from a chemical reaction. This chemical reaction is between two reagents, typically a substrate and an oxidant. The reaction produces a product or an intermediate that is unstable and releases a photon as it changes to a lower energy state. One such commonly used system uses a streptavidin substrate that reacts with the oxidant enzyme horseradish peroxidase (HRP). When the HRP enzyme reacts with the streptavidin substrate light is released. This light is then quantified with a detection system.
Magnetic nanoparticles are interesting little tools. They are not magnetic themselves, butmagnets can control them. They are deemed safe for use in biological and medical applications, but they have a seemingly mysterious ability to “bind” to “anything” a scientist or doctor wants them to. They can isolate cells and DNA, destroy tumors, and deliver drugs to specific cells or tissues. How can all of this be so? As with most things, the answers to these mysterious properties can be found by examining the way magnetic nanoparticles are constructed.
The American Association for Clinical Chemistry (AACC) is holding its annual meeting in Atlanta, Georgia this year from Sunday, July 26th until Thursday, July 30th. The meeting is composed of two parts: the annual meeting conference and the clinical lab expo.
The annual meeting conference contains mini-tracks focusing work into eight areas of laboratory medicine practice, plenary sessions, symposia, brown bag sessions, and opportunities to speak with experts in the field. The clinical lab expo features representatives from more than 700 laboratory products and services companies. The representatives will have equipment on display to demonstrate the newest breakthroughs and improvements to their products. They will also be able to field any questions that may arise. Bryan Rittenberry of SEPMAG will be found at booth #4714 of our partner PERCORSO LIFE SCIENCES. Stop by and take a look at SEPMAG’s newest products!
