Exosomes were first discovered in the supernatant of sheep red blood cells cultured in vitro. They are vesicle-like bodies that are actively secreted by cells and are relatively uniform in size, with a diameter of 30-100 nm and a density of 1.10~1.18 g/ml. With the continuous development of molecular technology, the exploration of exosomes in the biological community has become increasingly deep. In 2013, three foreign scientists were awarded the Nobel Prize in Physiology or Medicine for their breakthrough in the study of cell membrane transport mechanisms. As a result, the study of exosomes has reached a new height.
In recent years, more and more evidence has shown the importance of exosomes for clinical treatment. Exosomes are intercellular messengers that provide strong evidence for further clinical diagnosis through changes in their numbers and biochemical composition. It carries a variety of proteins and miRNAs, is involved in cell signal transduction, cell migration, angiogenesis and tumor cell growth, and may become a natural carrier of drugs for tumor detection or clinical treatment.
However, at present, domestic experience in exosomes research is very limited. Whether it is centrifugation, filtration centrifugation or immunomagnetic beads, the content, purity and biological activity of exosomes cannot be guaranteed at the same time. This first restricts the production of exosomal samples, which in turn makes it difficult to characterize subsequent samples. The limitations of measurement techniques have also greatly hindered the research progress of exosomes in these fields.
In order to keep pace with the international advanced level and promote the development of China's medical industry, so that more Chinese patients can get a good opportunity for rehabilitation, a third-grade hospital in Guangzhou seized the opportunity of domestic and foreign body research and launched a campaign against myeloma this year. Exosome characterization work. But first, they made a difficult decision on the choice of research equipment.
In the current mainstream exosome characterization methods in the Chinese market, researchers generally choose electron microscopy, flow cytometry and dynamic light scattering. However, electron microscopy can only observe a limited number of particles at a time, and there are serious shortages in the representative. At the same time, due to the complicated preparation process of the electron microscope, it is easy to cause changes in the morphology and state of the sample; flow cytometry is currently recognized The lower limit of the measured particle size is about 300 nm, which greatly exceeds the upper limit of the size of the exosomes; while the dynamic light scattering technique is not suitable for the measurement of polydisperse complex exosomes, and the concentration of exosomes in the sample cannot be obtained.
Later, after careful analysis and comparison of the world's top research equipment, the hospital began to pay attention to the products of Malvern Instruments Ltd. (hereinafter referred to as "Malvern"). As a global leader in materials and biophysical characterization, Malvern has a reputation for providing high performance particle characterization solutions to a wide range of customers around the world. In particular, it adopts the NanoSight product line of the new generation of nanoparticle tracking and analysis technology (Malvin patented technology, hereinafter referred to as NTA), which can directly and in real-time observe the nanoparticles, collect the scattered light signals of the nanoparticles through optical microscope, and photograph them in solution. The image of Brownian motion is used to track and analyze the Brownian motion of each particle to calculate the hydrodynamic radius and concentration of the nanoparticle. This novel nanoparticle characterization approach immediately attracted the hospital. Sure enough, Malvern did not let them down.
Improve functionality and respond to customer needs in all aspects
From approaching to accepting NTA technology, the hospital decided to use the latest model of the Malvern NanoSight series, the NS 300 Nanoparticle Tracking Analyzer (hereafter referred to as "NS 300"), in just three months. For this cooperation, Malvern NanoSight product expert Mr. Mei Jie said: "It is not our experts who persuade customers, but Malvern's products themselves."
After providing detailed equipment training for the hospital, the Malvern NS 300 was immediately put into use in research. Soon, it was recognized by the customer research team for its superior performance and ease of operation.
Excellent quality control
The extraction of exosomes has always been a difficult problem for all relevant researchers. There are many types of vesicles in biological cells. How do you prove that the extracted particles must be exosomes? Electron microscopy is effective in identifying a certain number of particle properties, but as mentioned earlier, electron microscopy is not suitable for rapid analysis of large numbers of particles, while dynamic light scattering techniques can only detect relatively uniform distribution of sample particles, and Fluorescent function.
The Malvern NS 300, equipped with advanced NTA detection technology, has a powerful function at this time: it can perform strict quality control, and by analyzing and calculating all the observed particles, the sample size is given in detail at the first time. Specific information on distribution and concentration. At the same time, researchers can use fluorescence to calibrate specific exosome particles, select one of four different wavelengths - 405nm, 488nm, 532nm and 635nm - with corresponding filters to achieve The measurement of the fluorescent sample is then separately tested by NTA technology to protect it from the environment of complex samples (such as serum, urine, etc.). The ability to resolve complex samples is critical for subjects like exosomes.
Especially critical, because NTA works by illuminating a sample (a solution of suspended particles) by passing a beam of concentrated laser light through a glass prism, and chrome plating on the glass surface minimizes the background signal, allowing researchers to pass The microscope directly observes the Brownian motion of the nanoparticles in solution, and images, and tracks and analyzes the Brownian motion of each particle to quickly and accurately calculate the hydrodynamic radius and concentration of the nanoparticles in the sample. Compared with other traditional technologies, NTA can fully characterize particles with particle size ranging from 10nm to 2000nm in suspension, and has extremely high resolution. It can still accurately analyze particles with similar particle size, especially suitable for external applications. Research on complex systems such as secretions, protein aggregation, drug delivery, nanoparticle toxicology, viruses and vaccines.
In addition, Malvern NanoSight can also determine the number of particles, accurately indicate the particle volume per unit volume and the number of particles in the sample solution, and conduct volume-based particle size testing and distribution testing. For research cases where the customer may have insufficient sample size, the Malvern NS 300 can also help achieve the established monitoring objectives by supporting low concentration tests (up to 300 microliters); under the same conditions, traditional electron microscopes are difficult to achieve. Statistical analysis.
Easy to operate and high efficiency
Often, large instruments (such as flow cytometers) require complex warm-up and calibration preparations before use. The Malvern NS 300 does not need to do this, it can be used directly as long as it is connected to a power source. And because the NTA technique uses the calculation of the Stokes-Einstein equation, which provides an irrelevant mass, refractive power, and hydrodynamic diameter of the granular material, the instrument can skip the cumbersome calibration and go directly into the research analysis. Save staff time before research.
As an instrument with a high level of integration and automation, the Malvern NS 300 combines hardware and software, camera and microscope to integrate particle detection and nanoparticle analysis to provide easy characterization of nanoparticles. A repeatable platform to use. The 40cm x 25cm device host integrates an ultra-high sensitivity scientific grade sCMOS photosensor, a temperature control unit and a laser with four selectable wavelengths. The sample cell and laser module can also be easily disassembled and assembled for easy movement and cleaning and for high throughput testing. The powerful software analysis capability allows the Malvern NS 300 to plot the particle size—corresponding to the quantity distribution intensity—the three-dimensional spectrum of the scattered light intensity in a very short time, and to obtain comprehensive information on the particle size of the particles. This not only reduces the probability of human error, but also greatly increases the efficiency of researchers.
According to the customer, before using the Malvern instrument NS 300, it would take an afternoon to use the flow cytometer to do four experimental projects. Now, with the Malvern NS 300, it can be easily done in an hour. The analysis results are comprehensive and reliable. For them, this not only saves a lot of time, accelerates the entire scientific research process, but also saves the hospital valuable labor costs.
"The common characterization instruments on the market often only have a single function and cannot meet our all-round requirements. The reason why we finally chose the Malvern NS 300 is to consider its functional perfection. It can be said that NS so far 300 has provided us with a lot of help," said a hospital doctor named Tang in the Department of Hematology.
Value-added service guarantees product best condition
As the market leader in particle characterization technology, Malvern continues to bring the best technology in the industry to China, allowing customers to buy more than just a hardware, but a complete solution. In addition to technological innovation, Malvern has always focused on customer service. Its technical team is three times as many as the sales team. It covers academic experts, application experts and service engineers. They will participate in customer research and gain an in-depth understanding of customer needs. It enhances product value.
In this cooperation, in addition to high-quality products, the professional application support provided by Malvern is also the key reason for the hospital to choose Malvern. In the communication phase of equipment procurement, Malvern provides customers with detailed product consultation to help them purchase equipment according to specific research needs. At the beginning of the use phase, Malvern also arranged professional guidance training, and gave many professional suggestions for the customer's experimental application environment, helping customers to quickly familiarize themselves with the equipment and meet the needs of specific experimental objectives, faster, better and more The technical characterization results are obtained in a targeted manner.
In the after-sales phase, Malvern engineers also provided comprehensive repair and maintenance services for the hospital, responding quickly to their requirements, helping them diagnose and solve problems encountered during use, ensuring that the instrument is always at its best. Work status and improve customer satisfaction.
Summary and outlook
With the help of Malvern NS 300, the hospital has made initial progress in exosome research characterization, with strong evidence to verify the concentration of normal tissue cells and tumor tissue cells in exosome size and particle size distribution. difference. At present, more experiments are still in progress, and I believe that there will be strong support from Malvern NS 300, and more research progress will be made in the near future.
Although the study of exosomes as biomarkers is still in its infancy in China, it has shown great potential for development in the field of clinical treatment. In clinical diagnosis, it is an essential requirement to measure exosome concentration and particle size in a complex biological background simply and quickly. The existing methods cannot solve this problem perfectly. As a new measurement technology, NTA has real-time observation and fluorescence measurement functions, which can accurately measure particle concentration with high resolution, thus providing new ideas for exosome size and concentration research. With the further disclosure of research institutes and research projects, the new generation of NTA technology represented by Malvern NanoSight will make greater contributions to the promotion of exosome research and even human health.
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