In July 2015, 100 geneticists gathered at the New York Genome Center to discuss the yeast. The Saccharomyces cerevisiae gene, which contains 12 million base pairs, is the longest genome ever produced by scientists. Andrew Hessel, a researcher at Autodesk Software's Bio/Nano research group, was invited to speak at the conference. The audience asked him what kind of organisms would be synthesized next. “We are working on the most complex genetic engineering in the world,†Hesel said. “Why don’t you set your goals farther? Start with human genes.â€
The bold speech caused discussion among the participants. Soon after, Hesser contacted Harvard University's famous geneticist George Church to test his interest in the so-called Human Genome Project 2.0. "It seems obvious to me," Hesel recalls. "If we can read and analyze the human genome, then we should be able to write it."
A year later, Hesell’s vision came true. In May 2016, a number of scientists, lawyers, and government representatives gathered at Harvard University to discuss the HGP-Write program, which aims to synthesize the entire genome of humans from chemical components and let them Get function in living cells. Scientists have already launched the ambitious Human Genome Project (HGP), a $3 billion HGP program that hopes to measure the nucleotide sequences contained in human chromosomes, map the human genome, and ultimately decipher the genetic code. . As of 2005, the sequencing of the Human Genome Project has been largely completed (92%). This new HGP-Write program will be based on previous research.
Church is one of the main advocates of the Harvard workshop, and Church is working on the synthesis of 4.5 million base pairs of the E. coli genome. Another advocate is geneticist Jef Boeke, who led the New York University team to successfully synthesize Saccharomyces cerevisiae chromosomes for seven years. "I think we all realize that we both have done well enough on these two genomes, and we should move toward a bigger goal," Church said.
The scientific papers published after the conference formally proposed the seminar: vigorously develop DNA synthesis technology, making artificial production of genes easier, faster and cheaper. Currently, we can synthesize short-stranded DNA containing 200 base pairs, but the average number of base pairs on a natural gene can reach thousands. And the current methods of gene synthesis are also too inefficient and costly. In the biological sciences, DNA synthesis is the basis of all experiments. Cancer research and vaccine development depend on this. So, although the current methods are cumbersome, scientists have no choice.
The automatic biochemical analyzer is an instrument that measures a specific chemical composition in body fluids according to the principle of photoelectric colorimetry. Due to its fast measurement speed, high accuracy and small consumption of reagents, it has been widely used in hospitals, epidemic prevention stations and family planning service stations at all levels. The combined use can greatly improve the efficiency and benefits of routine biochemical testing.
principle
The automatic analyzer is to automatically run all or part of the steps of sampling, mixing, warm bath (37°C) detection, result calculation, judgment, display and printing results and cleaning in the original manual operation process. Today, biochemical tests are basically automated analysis, and there are fully automatic biochemical analysis systems designed for large or very large clinical laboratories and commercial laboratories, which can be arbitrarily configured according to the laboratory's testing volume.
Whether it is the fastest-running (9600Test/h) modular fully automatic biochemical analyzer today, or the original manual-operated photoelectric colorimeter for colorimetry, the principle is the use of absorption spectroscopy in spectroscopic technology. It is the most basic core of the biochemical instrument.
Optical system: is a key part of ACA. Older ACA systems used halogen tungsten lamps, lenses, color filters, and photocell assemblies. The optical part of the new ACA system has been greatly improved. ACA's beam splitting system can be divided into front splitting and rear splitting due to different light positions. The advanced optical components use a set of lenses between the light source and the cuvette to convert the original light source. The light projected by the lamp passes through the cuvette to bring the beam to the speed of light (unlike traditional wedge beams), so that the spot beam can pass through even the smallest cuvette. Compared with traditional methods, it can save reagent consumption by 40-60%. After the spot beam passes through the cuvette, the spot beam is restored to the original beam through this group of restoration lenses (wide difference correction system), and is divided into several fixed wavelengths (about 10 or more wavelengths) by the grating. The optical/digital signal direct conversion technology is used to directly convert the optical signal in the optical path into a digital signal. It completely eliminates the interference of electromagnetic waves to the signal and the attenuation in the process of signal transmission. At the same time, the optical fiber is used in the signal transmission process, so that the signal can achieve no attenuation, and the test accuracy is improved by nearly 100 times. The closed combination of the optical path system makes the optical path without any maintenance, and the light splitting is accurate and the service life is long.
Constant temperature system: Since the temperature of the biochemical reaction has a great influence on the reaction results, the sensitivity and accuracy of the constant temperature system directly affect the measurement results. The early biochemical instruments used the method of air bath, and later developed into a dry bath with constant temperature liquid circulation which combines the advantages of dry air bath and water bath. The principle is to design a constant temperature tank around the cuvette, and add a stable constant temperature liquid that is odorless, non-polluting, non-evaporating and non-deteriorating in the tank. The constant temperature liquid has a large capacity, good thermal stability and uniformity. The cuvette does not directly contact the constant temperature liquid, which overcomes the characteristics of the water bath type constant temperature being susceptible to pollution and the uneven and unstable air bath.
Sample reaction stirring technology and probe technology: The traditional reaction stirring technology adopts magnetic bead type and vortex stirring type. The current popular stirring technology is a stirring unit composed of multiple groups of stirring rods that imitate the manual cleaning process. When the first group of stirring rods is stirring the sample/reagent or mixed solution, the second group of stirring rods performs high-speed and high-efficiency cleaning at the same time. The set of stirring bars also undergoes a warm water washing and air drying process at the same time. In the design of a single stirring rod, a new type of spiral high-speed rotating stirring is adopted, and the rotation direction is opposite to the spiral direction, thereby increasing the stirring force, the stirred liquid does not foam, and reducing the scattering of light by microbubbles. Reagent and sample probes are based on the principle of early capacitive sensing, but slightly improved to increase the alarm of blood clots and protein clots, and re-test results according to the alarm level, reducing sample aspiration errors and improving the reliability of test results. . Large-scale biochemical instruments can detect more than 1,000 tests per hour, so automatic retesting is very important. Subjective evaluation of test results and manual retesting can no longer meet clinical needs.
Other aspects: barcode recognition of reagents and samples and computer login. Due to the lack of barcode recognition function of early biochemical instruments, there are more opportunities for errors. In recent years, both imported and domestic chemical instruments have adopted barcode detection. The use of this technology in biochemical instruments has provided technical support for the development of high-speed ACA, and also made the instrument quite supportive. The software development is simple and easy, therefore, barcode detection is the basis for the intelligence of the instrument. Open reagents, as an important factor for hospitals to choose models, whether the instrument supports open reagents is very important. After the reagents are opened, hospitals and scientific research units can choose their own reagent suppliers, and have a greater degree of freedom in measuring the price, the reliability of the test results, and the validity period of the reagents. Ion Selective Electrode Analysis Accessory (ISE), human serum and urine electrolyte indicators are very important, and hospitals can save money by adding ISE to the ACA system.
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