Application of freeze-dried bead ball technique in in vitro diagnosis of pets

ADD TIME:2019-08-28 11:20:08

With the continuous improvement of people's living standards, the number of pets has also increased rapidly. According to statistics, in 2016, China's pet market consumption reached 122 billion, which has truly become a billion-dollar economy. As people pay more and more attention to the health of pets, the scale of detection and diagnosis of pet's conventional diseases is also growing rapidly in animal hospitals.

       In the current clinical work of pets, there are widespread problems in which some pathogens are difficult to diagnose or cannot be accurately diagnosed.

1 The existing diagnostic techniques have low sensitivity. For example, colloidal gold test papers can provide rapid diagnosis, but detection of pathogens from protein levels has certain cross-reactions and animal autoantibody interference, which leads to the diagnosis of clinical application. Quasi-results.

2 The use of traditional diagnostic techniques (colloidal gold test strips and ELISA assays) does not provide an accurate diagnostic basis for early diagnosis of disease (eg, incubation period) and diseases with high antigenic requirements. Such as clinical common canine distemper and parvovirus;

3 In the process of prevention and treatment of epidemics, it is difficult to distinguish whether the antibodies detected by serology are caused by vaccine immunization or viral infection. There are some cases in which there are some pathogens in the case of microdiagnosis, such as small Babesia.

       PCR (Polymerase chain reaction) polymerase chain reaction-in vitro nucleic acid amplification detection technology, has the outstanding advantages of specificity, sensitivity, high yield, fast, simple, reproducible and easy to automate; it can be studied in a test tube. The target gene or a DNA fragment is amplified to 100,000 or even a million times in a few hours, allowing the naked eye to directly observe and judge; a sufficient amount of DNA can be amplified from a hair, a drop of blood, or even a cell. Analytical research and test identification. Things that can only be done in the last few weeks can be done in a few hours with PCR. PCR technology is a revolutionary pioneering and milestone in the field of biomedicine. Whether it is in the field of pet diagnosis or human diagnosis, it has broad application prospects. Therefore, many biotechnology companies have begun to increase investment in research and development of PCR technology.

       PCR detection technology enables accurate detection of pathogens. PCR (especially real-time PCR) makes accurate diagnosis of these diseases a reality. Relevant regulations have clearly listed viral nucleic acid testing (rather than test card detection) as a diagnostic criterion for many animal diseases, which also indicates the importance of nucleic acid detection in the diagnosis of animal diseases. Choosing a suitable PCR is extremely important for the diagnosis of pets

       In clinical work, there are a lot of PCRs for veterinarians to choose. After the reagent components of PCR are mixed, the PCR reagents in liquid state will gradually degrade and fail at room temperature, so there is a short storage time, and high cost cold chain transportation is required. Inconvenient use of the problem.

       With the advent of freeze-dried bead pellet technology, PCR technology has developed rapidly. Liquid nitrogen, its excellent properties (inert - does not react with other substances), and reasonable price, determines that liquid nitrogen is an ideal low-temperature freezing medium. The test reagent is quickly frozen into a small ball by liquid nitrogen in a professional device, and the water inside the reagent pellet can be completely sublimated by the vacuum freeze-drying technique without destroying the active ingredient. After lyophilization, the reagent becomes a solid pellet state, which can be stored at room temperature in a solid state, without the need of cold chain transportation, the product storage period is greatly extended, and the logistics cost is greatly reduced. When used, the solid spheres are highly resolubilized, and the sample liquid can be dissolved quickly, and then used like a normal PCR reagent, which is the development trend of the current PCR reagent treatment. The United States IDEXX company is a well-known multinational biological diagnostic company that is at the forefront of the application of liquid nitrogen freeze-dried beads.

       With the increasing demand in the pet market, many pet diagnostic reagent companies are working to improve the convenience of in vitro diagnostic products. At present, many companies choose to make diagnostic reagents into freeze-dried bead pellets, freeze-dried and put into design. In the reagent tray, the operator can simply operate as required, which greatly facilitates the user's rapid diagnosis and use.

       But at this stage, it is a technical difficulty for the pet diagnostic reagent to freeze the bead pellets, how to accurately spot the liquid, the consistency of the product, and the production speed.

1. Micro-dot: pet diagnostic reagents The freeze-dried bead pellets require a small amount of liquid. The common amount of liquid is from 1 microliter (1 mg) to tens of microliters. Pipettes that people are familiar with are difficult to continue to stabilize in such a small range and to ensure a consistent amount of liquid. Because the technical principle determines the accuracy is not high, the fluid control is not good, coupled with the human factors of the operating staff, it is easy to cause the shape of the ball to be different, the shape of the ball is not good, or the ball falls on the surface of the liquid nitrogen. Open into multiple microspheres.

2. Precision point liquid: pet diagnostic reagent freeze-dried ball with high precision and shape requirements. When the laboratory is operating, due to manual consistency problems and simple equipment, it is often difficult to control the accuracy and consistency of the ball. In the case of a small amount of liquid, when the amount of liquid is small, a spherical ball having a uniform shape cannot be formed, and when the amount is large, the freeze-dried ball is difficult to reconstitute. If the shape of the finished freeze-dried ball is inconsistent and the size is different, it will affect the subsequent detection process and test results.

3. Industrialization and low-cost mass production. Traditional manual production, due to low efficiency, human factors affect product consistency and stability, coupled with the increase in labor costs, it is difficult to achieve mass-market production at low cost.

       In order to solve the above problems, the technical team of Guangzhou Ascend Precision Machinery Co., Ltd. has been focusing on the development and manufacture of liquid nitrogen freeze-dried bead ball system since 2012, focusing on micro-upgrading other micro-point liquids and breaking through liquid nitrogen. The precision of the spotting process in the production process is not good, and the sphericity and uniformity are difficult. Based on solid microfluidic pump technology, Guangzhou Feisheng team has introduced DS228 desktop system and DS328 floor-standing system suitable for laboratory/small batch production and mass production of various liquid nitrogen freeze-dried beads. The quantity is as low as 1 microliter. It is used for semi-automatic and automated production of liquid nitrogen freeze-dried beads for well-known bioengineering companies and biological research laboratories in Taiwan, Shenzhen, Chengdu, Tianjin, Ningbo, Zhuhai and Xiamen. The ball's system solution has become a professional system supplier in the application field of liquid nitrogen freeze-dried beads.

Below is a brief introduction to two professional freeze-dried bead ball machines.


DS228Desktop liquid nitrogen freeze-dried beads production


DS328Floor-standing liquid nitrogen freeze-dried bead production system

The DS228 and DS328 liquid nitrogen freeze-dried bead systems use precision micro-ceramic pump technology with a liquid volume as low as 1 μl. The parts in contact with the liquid are medical grade sapphire grade ceramics, Teflon and 316 stainless steel materials. It does not react with diagnostic reagents, thus ensuring the activity, stability and contamination of the reagents. The DS228 and DS328 systems can quickly adjust the dispensing volume and the dispensing speed. In addition, the company can customize a variety of special needles to achieve high-efficiency spotting, no dripping of liquid, and does not blast when it is placed in liquid nitrogen. The freeze-dried bead ball has a good circular effect, uniform shape and volume, and uniform size, which effectively solves the problem that the freeze-dried bead ball that the customer generally faces is easy to hang or blast, the precision is not accurate, the ball formation effect is poor, and the consistency is poor. problem. Guangzhou Feisheng Co., Ltd. has a variety of micro-ceramic pumps to choose from, as low as 1 microliter to more than tens of microliters of liquid volume range can achieve high-precision liquid point, point liquid accuracy up to 0.5%, can meet The customer's various precise point requirements.

The DS228 and DS328 systems enable automated production. The parameters of the automated production can be easily set by two displays. Display 1 is a micro pump controller; it is mainly used to control various point parameters of the micro pump. Display 2 is the system operation panel and is mainly used to control the overall parameters of the entire liquid nitrogen freeze-dried bead system. Both the DS228 and DS328 systems can be configured with single or multi-channel micropump dispensing systems. Single channel micropump systems are suitable for laboratory or small batch production, and multichannel microsystems are suitable for mass production.

The DS228 and DS328 systems feature a unique mechanism designed to facilitate rapid collection and storage of freeze-dried beads. The system comes with an integrated liquid nitrogen tank and an optional safe addition liquid nitrogen unit.

The DS228 and DS328 systems have a small amount (1 μL), high precision (0.5%), high efficiency (100-200 PPM), high freeze-dried bead ball consistency, and the technical advantage of automated continuous production. The preferred system for beading balls.