Demand analysis and technology selection of biosafety cabinet use and maintenance
Bio-safety cabinets (BSCs) are technical products that use air purification technology to achieve the first physical isolation. When it is used to manipulate infectious materials such as primary cultures, bacterial strains, and diagnostic specimens, It is designed to protect the operator, the laboratory environment, and the laboratory materials from exposure to infectious aerosols and spills that may occur during the above operations. An aerosol may be produced when a liquid or semi-fluid is operated, such as shaking, pouring, stirring, or dropping a liquid onto a solid surface or another liquid. The agar plates were streaked, the cell culture flasks were inoculated with a pipette, and the suspension of the infectious agent was transferred to a microplate using a multi-channel applicator, and the infectious material was homogenized and vortexed to the infection. These laboratory procedures can produce infectious aerosols when the liquid is centrifuged and subjected to animal operations. Because the naked eye can not see the diameter is less than 5 p. The aerosol of m and the tiny droplets of diameter (5-1o0)pan, so laboratory workers are generally unaware of the formation of particles of this size and may inhale or cross-contaminate other materials on the work surface. Proper use of biosafety cabinets has been shown to reduce laboratory infections and cross-contamination of cultures due to aerosol exposure. Biosafety cabinets also protect the environment.
1 Basic status of biological safety cabinet
Before the SARS in 2003, only the Ministry of Agriculture, the Center for Disease Control, and the microbiology research institutes used biologically safe cabinets for institutions that contact strong pathogenic pathogens. The biosafety cabinets used were mainly imported from Europe, America or Singapore. Biosafety cabinet manufacturer.
After SARS, the use of biosafety cabinets has received great attention due to the WHO Laboratory Biosafety Manual, 3rd edition, CNAS-CL05-2006, Laboratory Biosafety Recognition Guidelines, WS 233-2002, Microbiology and Biomedicine. General Standards for Laboratory Biosafety, GB 19781-2005/ISO 15190:2003 "Safety Requirements for Medical Laboratories" and GB 19489-2004 "General Requirements for Laboratory Biosafety", YY0569-2005 "Biosafety Cabinet" and other standard requirements and With the introduction of the guidelines, in recent years, medical and health institutions and disease prevention and control institutions have paid more and more attention to biosafety protection facilities. As a biosafety cabinet for biosafety protection equipment, its demand Ft has gradually increased.
At present, domestic biosafety cabinets are widely used in medical and health, disease prevention and control, medical care, food hygiene and other laboratory and research institutions. They are also used in biopharmaceuticals, environmental monitoring, and scientific research institutions. Wantai. In the initial stage, the main solution was to fill in the gaps and meet the needs of users. It did not pay enough attention to the safety maintenance of users of biosafety cabinets. As the vast majority of manufacturers, their work focuses on production and market, and does not carry out on-site installation inspection and maintenance inspection during use; as a unit of use, due to lack of knowledge of product structure and protection principles, no installation acceptance and During the maintenance and inspection of the safety awareness, it is safe to use the safety cabinet once and for all.
In fact, in order to standardize the quality of biosafety cabinets, Beijing Medical Device Inspection Institute began to develop biosafety cabinet standards as early as 2004. YY 0569—2005 “Biosafety Cabinet†industry standard was released in 2005 and officially implemented on June 1, 2006. This standard draws on the requirements and testing methods of NSF/ANSI 49-2002 and EN12469:2000, such as The NSF/ANSI49-2002 standard for the classification of secondary biosafety cabinets is divided into four types: A1, A2, Bl, and B2. The characteristic test for personnel protection detection in EN 12469:2000 is used to test KI-Discus (potassium iodide) test. law. At the same time, according to the status quo of the Chinese market, some performance requirements are innovatively proposed with reference to the two standards, such as real-time airflow display, alarm system, three-sided forming of working area and negative pressure design; installation and annual maintenance inspection in the standard All have put forward clear technical requirements.
2 Biological safety cabinets (BSCs) characteristics, classification and application options
The basic design of biosafety cabinets has undergone several improvements over the years. The main change is the addition of HEPA filters to the exhaust system. For particles of 0.3 tan diameter, the HEPA filter can retain 99.9r7%, while for larger or smaller particles it can retain 99.99%. This property of the HEPA filter makes it possible to effectively trap all known infectious agents and ensure that the microbial free air is discharged from the safety cabinet. A second improvement in the design of biosafety cabinets is the delivery of HEPA-filtered air to the work surface to protect items on the work surface from contamination. Experimental object protection
(product protee.tion)o
The biological safety cabinet is a ventilation device that provides personnel protection and environmental protection during the microbial experiment. Some types of biological safety cabinets can also provide a clean local environment for the experiment to protect the experimental materials and prevent cross-contamination between the experimental materials. Biosafety cabinets are classified into three levels: Class I Biosafety Cabinet, Class II Biosafety Cabinet, and Class III Biosafety Cabinet according to their structure and ability to achieve protection.
Class I biological safety cabinet, the inlet air from the front window operation port (called inflow airflow) is not lower than O. The low-speed 40 m/s enters the biosafety cabinet. The air passes through the surface of the workbench and is discharged to the biosafety cabinet through the exhaust duct to provide personnel protection. The airflow polluted by the experiment is filtered through a high-efficiency filter and discharged from the laboratory to protect it. The laboratory environment is not contaminated with microbial factors. However, since the laboratory air directly enters the experimental operation area through the operating front window, the Class I biosafety cabinet cannot provide a clean environment for the experimental operation area, and has no function of protecting the experimental materials, so it has been rarely used at present.
Table 1 Differences between Class I, Class II, and Class III biosafety cabinets
Note: Work cabinets that flow out of the air in both horizontal and vertical directions ("Ultra Clean Workbench") are not part of the biosafety cabinet. Nor can it be applied to biosafety operations.
The Class II biosafety cabinet is similar to the Class I biosafety cabinet of the Laboratory Medicine Network. It provides personnel protection through the front window operation port of the biosafety cabinet. The airflow polluted by the experiment is filtered through the high efficiency filter and discharged from the laboratory to protect the environment. Not contaminated by microbial factors. However, since the inlet of the window operation port does not directly enter the experimental operation area, but is filtered in the biosafety cabinet through the high-efficiency filter at the top of the work area, it flows downward in a laminar flow to the operation area (referred to as a descending air flow). It not only provides a clean environment for the experimental operation area, but also protects the experimental materials from environmental pollution. At the same time, the laminar flow prevents cross-contamination of aerosols generated by materials in different areas of the operation area.
Class II biosafety cabinets are divided into four types, A1, A2, B1 and B2, according to their structural characteristics and airflow patterns. Among them, the airflow of the A1 and A2 biosafety cabinets is powered by a single fan in the safety cabinet. 70% of the fan air volume circulates in the safety cabinet to form a descending airflow, 30% is directly discharged into the laboratory, or is soft through the casing. The connecting tube is discharged outside the laboratory. This 30% of the air volume is supplemented by the flow of people. Since the exhaust passage of the A1 type biosafety cabinet is positive pressure, once it occurs, the polluted airflow leaks directly into the laboratory and has structural defects. It has now been basically replaced by the A2 type biosafety cabinet. 30% of the airflow of the B1 biosafety cabinet circulates in the biosafety cabinet to form a descending airflow, and 70% of the airflow is directly discharged from the laboratory through the fully enclosed hard-connected pipeline. The 70% of the airflow is supplemented by the flow of the flow, and its power is mainly Exhaust fans from outside the laboratory. The inflow and downflow of the B2 biosafety cabinet are completely exhausted from the outside by the laboratory's external fan through the closed hard-connected duct. The downdraft is powered by the fan in the biosafety cabinet, and the inflow airflow is caused by the difference in airflow provided by the two fans. Guarantee. From the perspective of the ability to prevent microbial aerosol contamination, the four types of biosafety cabinets Al, A2, Bl and B2 are identical. Since the B1 and B2 biosafety cabinets directly discharge airflow out of the laboratory, they show their advantages when generating toxic gases during the experiment. On the one hand, toxic gases can be completely discharged from the laboratory to prevent harm to the experimental personnel. In particular, the B2 type biosafety cabinet does not have gas circulating in the cabinet, and it can also avoid the circulation of gas that has an influence on the experiment generated in the experiment into the experimental area. Currently widely used are Class II A2 and B2 biosafety cabinets.
Class III biosafety cabinets are used to operate dangerous grade 4 microbiological materials and provide the best personal protection. All interfaces of the Class III biosafety cabinet are “sealedâ€, the air supply is filtered by HEPA, and the exhaust air passes through two HEPA filters, further enhancing the environmental protection. The Class III biosafety cabinet is controlled by an external, dedicated exhaust system that keeps the interior of the cabinet under negative pressure (not less than 120 Pa). Only by the strong rubber gloves attached to the biosafety cabinet can the hand reach the work surface. Class III biosafety cabinets should be equipped with a sterilizable transfer box with a HEPA filter exhaust. The Class III biosafety cabinet can be connected to a double-door autoclave and used to remove contamination from all items entering and leaving the biosafety cabinet. Several glove boxes can be joined together to increase the work area. Class III biosafety cabinets are suitable for laboratories with Class III and Class 4 biosafety levels.
3 The main problems in the use and maintenance of biological safety cabinets Biosafety cabinets have been widely used in medical institutions, disease prevention and control institutions, health care, food hygiene and laboratory-level research institutions, including hospitals and research laboratories. The amount accounts for a large proportion. Through research, we can find that there are three main aspects that directly or indirectly affect the safety and use of biological safety cabinets. One is the manufacturer, the other is the use unit, and the third is the third-party testing organization.
1) Problems with manufacturers
(1) The technical foundation is weak
The technical conditions of the manufacturer's production process are uneven. From the perspective of product registration and inspection, most of the production enterprises were originally engaged in the production of purification equipment. The production of biosafety cabinets has seen a broad market development prospect, even in the production of products, despite manufacturing. The enterprise standard of the business is based on YY 0569-2005 "Biosafety Cabinet", but the manufacturer does not have many testing conditions such as microbial protection. It is generally difficult to pass the inspection once the product is inspected, and it is often in the process of rectification to recovery. The repeated state of the test makes the test a verification design. Moreover, since the biosafety cabinet standard is based on the NSF/ANSI 49-2002 and EN 12469:2000 standards, domestic manufacturers have very limited knowledge of the standard, so there are often defects in product design that do not pass through microorganisms. Protection and other related tests are difficult to find. In the registration inspection, we also found that the first registered biosafety cabinet product has the most prominent and most problematic problems; even if the manufacturer who obtained the registration certificate uses the new process to design and produce the new model biosafety cabinet product, it will face some technical problems. Need to rectify, the design concept of various safety performance can not be effectively reflected in the overall performance operation of the product, of course, also affects the role of the biosafety cabinet safety barrier.
(2) Lack of self-regulatory awareness and technical service capabilities
The biosafety cabinet is still in the stage of registration inspection before the product enters the market and the stable stage of product quality. It is not in the stage of installation inspection, maintenance inspection and cycle inspection.
If the biosafety cabinet is not professionally installed, cycled, and maintained, the operating parameters are difficult to ensure that under normal conditions, the safety barrier of the biosafety cabinet is not functioned, and the operator, laboratory environment, and experimental materials cannot be guaranteed. Safety. Although the VI biosafety cabinet manufacturer started earlier and has extensive experience in testing and maintenance of biosafety cabinets, the imported biosafety cabinets are mainly agency systems, and are not mandatory for sales service costs and Chinese policies and regulations. The factors of installation and periodic inspection have resulted in the import manufacturer's biosafety cabinet not carrying out comprehensive installation inspection and routine maintenance inspection for domestic customers in accordance with the safety regulations of the country in which it is located. What's more, the products of the eliminated models and the products that do not meet the requirements of YY O569-2005 "Biosafety Cabinet" are sold in China. The lack of effective supervision in the later period, coupled with the lack of attention of foreign manufacturers on follow-up services, has serious security risks.
Domestic manufacturers are carefully prepared in type inspection. Subsequently, in order to bidding, market competition and other factors, the production cost is lowered, and the key components of the product (such as fans and filters) are randomly changed, resulting in loss or reduction of safety barrier performance; Technical investment, low profit, and low enthusiasm of manufacturers, and most domestic companies do not have on-site inspection capabilities to meet customer needs. These have seriously affected the quality of biosafety cabinets in China and also destroyed the environment for the sale of biosafety cabinets.
Most manufacturers, when selling biosafety cabinets, promised to install and debug and check the biosafety cabinet parameters after the biosafety cabinets were in place. They also promised a one-year warranty. However, in fact, due to the lack of corresponding follow-up supervision, and the lack of technical monitoring and maintenance methods by institutions and laboratories, most manufacturers do not provide effective training for after-sales installation and maintenance engineers, and the actual inspection operations of installation and maintenance engineers. The capacity is generally low, and the capacity is uneven. There is no professional equipment for installation and maintenance inspection. The installation and commissioning inspection is not in place. The installed equipment is tangible and cannot guarantee normal operation.
2) Use unit problem
(1) The use department pays attention to the degree of difference
The monitoring of the installation position, use status, maintenance and periodic inspection of the biosafety cabinet is an important part of the safe use of the operating agencies and laboratory operators and the safety of the test operation. It is also the health of the environment and other personnel. An effective means of security assurance. However, due to the fact that the use of the safety department is still in its infancy, the importance and necessity of installation, commissioning, maintenance and cycle inspection are not enough. This is mainly due to the lack of communication with the manufacturer before the site installation. Mismatches and prior defects in the placement, placement, and related configuration of the biosafety cabinet result in reduced life of the biosafety cabinet and unsafe operation.
I don’t know the technical indicators of product installation inspection, maintenance inspection and cycle inspection, and I have no confirmation ability, and I have not entrusted the third party to have the qualification of testing by qualified inspection agencies.
Medical institutions are the main body of biosafety cabinets. Due to the lack of safety protection system and lack of regulatory awareness, biosafety cabinets without medical device registration certificates will be used, not to mention the control of product technical indicators. Security. China Food and Drug Network has been exposed,
On November 5, Anqiu Food and Drug Administration seized two cases of biosafety cabinets using the registration certificate for non-medical device products. The instruments used by the two large medical institutions for AIDS testing did not have the "Medical Device Product Registration Certificate". After investigation, one hospital could not provide the "medical device product registration certificate" of the biological safety cabinet, and the "medical device product registration certificate" of the other hospital biological safety cabinet was forged. The Anqiu Food and Drug Administration has imposed penalties on two hospitals and conducted further investigations.
(2) Insufficient training
The training of relevant operators and maintenance monitoring personnel is not in place. The operator is unfamiliar with the correct operation and maintenance of the biological safety cabinet, which will lead to a significant reduction in the normal service life of the biological safety cabinet, burying safety hazards, and providing special equipment for safety barriers. Not safe.
3) Third-party testing agency issues
Due to the structural function of the biosafety cabinet and the special requirements of the use requirements, it is necessary to have a third-party testing agency with the qualification to conduct the test. However, so far, there are very few qualified third-party testing organizations. Due to the need for necessary bio-protection and the cooperation of manufacturers, the institutions and personnel who can carry out on-site inspection services are more scarce for the safety of inspectors.
4) Other issues
4 Ideas and technical requirements for solving the problem of using and maintaining biosafety cabinets
1) Solution ideas
We believe that the main ideas for solving the problem of using and maintaining biosafety cabinets are:
On the one hand, through policy support and third-party technical support, it helps agencies and laboratories to dynamically monitor and maintain biosafety cabinets that are about to be put into use and in use, improve the safety of biosafety cabinets, and reduce the occurrence of adverse events. . On the other hand, through the monitoring and evaluation of the installation, maintenance and cycle of the biosafety cabinet, the grounding causes the manufacturer to increase the input of personnel and technical services in product design verification, post-test and maintenance, and establish an effective quality management system to ensure The quality of after-sales products enhances the competitiveness of products and promotes the rational, effective and healthy development of the industry.
2) Technical demand focus
(1) Enhance the safety risk awareness of the use of biological safety cabinets and improve the ability of operators.
Strengthen the management of the biosafety cabinet equipment management department, increase investment, and make each operator clear operational skills and responsibilities through training;
Improve the awareness of safety risks in the equipment management department, perform their duties with due diligence, strictly follow the technical standards for installation, maintenance of problems, and annual cycle inspection;
To be correct and effective with medicine.
(2) Strengthen the service capabilities and awareness of manufacturers for biological safety cabinets.
To be strictly factory inspection, the factory safety cabinet should be tested by the platform and the platform should be qualified;
Actively communicate with users before installation, scientifically and rationally install biosafety cabinets;
The ability to install and maintain engineers should be actively upgraded, with the necessary special equipment to ensure the conditions for the installation of the biosafety cabinet.
(3) Play the role of a third-party testing agency
As soon as possible to improve policies and regulations, the implementation of the YY0569-2005 "Biosafety Cabinet" standard can be fully guaranteed to ensure the smooth implementation of installation, maintenance, and cycle inspection;
Third-party testing organizations should also continuously enhance their publicity, enhance their technical capabilities, quality, expand their influence, and establish a brand; third-party testing organizations should consider establishing a technology platform from contact to implementation to ensure the safe and effective use of biological safety cabinets. It also provides effective technical oversight for fair competition in the biosafety cabinet market.
5 Conclusions and recommendations
The administrative department can rely on the technical conditions of the third-party testing organization to implement on-site installation inspection of the biosafety cabinet, maintenance inspection during use, and annual cycle inspection to further effectively develop the biosafety cabinet manufacturer and the use organization. Supervise and manage so that:
To help improve the use and maintenance capacity of the biosafety cabinet of the institution, it can not only save equipment costs, but also improve the safety of the biosafety cabinet and reduce the occurrence of adverse events. Strengthen the management of the production source and terminal of the biosafety cabinet to improve its prevention. Sexual maintenance or maintenance awareness to ensure the safety of operators and other personnel;
Promote manufacturers to establish an effective quality management system, stabilize design processes, ensure product quality, enhance product competitiveness, promote technological innovation, and promote the healthy development of the industry.
The establishment of biosafety cabinet technology testing norms provides a technical basis for the effective control of biosafety cabinets nationwide, the safety effect is guaranteed, and the potential safety hazards existing in the use institutions are reduced, and the social benefits are enormous.
Due to the structural function and special requirements of the biological safety cabinet, the relevant testing personnel must undergo special training and use special equipment. Professionals from qualified institutions must conduct on-site installation inspection, maintenance inspection and periodic inspection of the biological safety cabinets in accordance with the W O569-2005 Biosafety Cabinet standard to ensure their safety and effectiveness.
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