In this lab we will be working with hazardous chemicals, cryogenic solutions, pathogenic and genetically modified organisms. These substances pose hazards to you, other people and the environment. We will therefore discuss the precautions necessary for handling these materials.
Eating, drinking, smoking and storing food and drinks are not permitted in the laboratory. Do not wear jewelry or a watch and keep your hands clean and your nails short at all times.
Wearing a lab coat is compulsory and it should be worn in the lab exclusively to confine possible contamination. The lab coat must be long sleeved and buttoned up to fully protect skin and street clothes from spills. The lab coat should also be laundered on-site or by a laundering service.
Gloves should always be worn when handling bio-hazardous materials or hazardous chemicals. Disposable latex gloves can provide an adequate barrier between the lab employee and most hazardous materials. However, when handling organic solvents and corrosive chemicals one should use nitrile gloves. Even though nitrile gloves are twice as expensive as latex gloves, many labs have chosen to use nitrile gloves exclusively because increasing numbers of people are developing allergies to latex.
Liquid nitrogen boils at −196 °C at atmospheric pressure, therefore it causes rapid freezing of any living tissue. Goggles are compulsory when working with liquid nitrogen. Liquid nitrogen can boil violently and splash cryogenic droplets upon contact with lab equipment, which may seriously harm the eyes. Due to its expansion rate of 1:694 only a minute volume of liquid nitrogen in a sample tube is necessary to break the tube. Hence, extra care should be taken when sampling plant material ground in liquid nitrogen.
A centrifuge is a device used for separating particles from a solution according to density. The centrifuge spins the samples around an axis to produce centrifugal forces; hence, increasing the magnitude of the gravitational field. The radial force generated by the spinning rotor is expressed relative to the earth's gravitational force and is therefore known as the relative centrifugal force (RCF) or the g force.
Rotors from different manufacturers can have different standards therefore, instead of using revolution per minute (rpm), we use relative centrifugal forces (RCF) to measurethe centrifugation force.
It is important to ensure that loads are evenly balanced before running centrifugation to avoid malfunctions of the centrifuge machine.
When evaluating the risks of working with genetically modified organisms (GMOs) one should consider all the risks associated with any non-GMO. Genetically modified plants do not pose any additional hazard to the scientist, however special care should be taken to avoid introducing GMOs into the environment. GMOs with novel traits could establish themselves in the wild and potentially disrupt the ecological balance. The following Safe Microbiological Techniques should be followed for work conducted with GMOs without pathogenic properties.
Inactivate biological waste:
Wash your hands with disinfecting soap after the experiment and before leaving the laboratory.
A biosafety cabinet(BSC) — also called a biological safety cabinet or microbiological safety cabinet — is an enclosed, ventilated laboratory workspace. A BSC protects the operator and the environment from pathogenic materials and volatile chemicals. There are three types of biosafety cabinets:
When working with pathogenic organisms the risks of infection and spreading must be assessed carefully. Organisms are divided into four categories of risk corresponding to the Biosafety levels (BSL):
Organisms in Risk Group 1 include several kinds of bacteria and viruses such as non-pathogenicEscherichia coliand canine hepatitis. BSL-1 can be used to conduct work on an open bench using Safe Microbiological Techniques.
Risk Group 2 includes various bacteria and viruses that cause only mild disease to humans, such as influenza A, or are difficult to contract via aerosols such as Malaria or沙门氏菌. In addition to BSL-1 work: - Laboratory personnel need specific training in handling pathogenic agents and are supervised by scientists with advanced training. - Only authorized personal can enter the laboratory. - Extreme caution must be taken for conducting work with sharp materials to avoid infection through injuries. - Procedures that yield infectious aerosols or splashes must be conducted in a safety cabinet, Class I or higher.
Potentially lethal pathogens that require BSL-3 could include yellow fever virus, rabies virus or the SARS coronavirus. In addition to the specific training required for working with lethal pathogens, all work must be conducted in biological safety cabinets while the laboratory must be built and designed with special engineering and safety features.
BSL-4 is required when working with pathogens such as Ebola virus and Smallpox. Personnel must use positive pressure personnel suits with segregated air supply. The laboratory must be completely isolated and have the following features: only accessible through multiple airlocks, contains multiple showers, a vacuum room, an ultraviolet light room and other safety precautions to destroy any trace of hazardous material. There are only a few dozens BSL-4 labs around the world.