As a "scientific research worker", how can I deal with reagents less?There is no shortage of toxic and harmful chemical reagents in the laboratory, which will affect personal safety if not properly operated. Today, Xiao Heng has taken stock of the common toxic reagents and protective measures in various biological experiments, and strives to be the first person responsible for the safety of his experiments.
Experimental safety
Dimethyl sulfoxide(Dimethyl sulfoxide, DMSO).
Use and Hazards: DMSO is a sulfur-containing organic compound, the molecular formula is (CH3)2SO, it is a colorless and odorless transparent liquid at room temperature, and it is a hygroscopic flammable liquid. It has the characteristics of high polarity, high boiling point, good thermal stability, aprotic, miscible with water, and can be soluble in most organic substances such as ethanol, propanol, benzene and chloroform, and is known as"All-purpose solvent", which is used in a wide range of applications. Because it can lower the freezing point of cells, reduce the formation of ice crystals, and reduce the damage of free radicals to cells, it is often used for cell cryopreservation. DMSO has a severe toxic effect, which interacts with protein hydrophobic groups, resulting in protein denaturation, which is vasotoxic and hepatorenal toxic.
Protective measures: to avoid its volatilization when using, you can prepare 1%-5% ammonia water for standby, ** can be rinsed with a large amount of water and dilute ammonia water after staining.
Polyethylene glycol(polyethylene glycol，peg)
Use and harm: It is often used for cell fusion, and can cause damage by inhalation, ingestion, and absorption.
Protective measures: Appropriate personal protective equipment, including lab coats, gloves, and goggles, must be worn to reduce the risk of exposure and inhalation.
Ultraviolet or ultraviolet light
Uses and hazards: Sterilization and disinfection, as well as observation of DNA. Commonly used UV light sources in laboratories include portable UV lamps and UV transilluminators. Ultraviolet or ultraviolet light can damage the retina of the eye. It can only be observed by means of a filter or safety glass that absorbs harmful wavelengths. Ultraviolet light triggers mutagenesis and carcinogenesis.
Protective measures: Never use the naked eye to observe ultraviolet light sources without protective devices. Wear appropriate prophylactic gloves when operating under UV light.
trizol
Uses and Hazards: Trizol is a reagent used for nucleic acid extraction, including RNA and DNA. Although it is not a direct carcinogen, the trizol reagent contains the toxic substance phenol, if you accidentally come into contact with trizol, you should immediately rinse with plenty of detergent and water, if you still feel unwell, you should consult and listen to your doctor.
Precautions: Safe operating procedures should be followed when used to reduce exposure and inhalation of chemicals. Make sure to operate in a fume hood.
Phenol(phenol，c6h6o）
Use and harm: It is mainly used to lyse cells, so that the depolymerization of proteins and nucleic acid substances in the cells is released. Highly toxic, can be absorbed through the respiratory tract, ** and digestive tract;Poisoning can cause headaches, dizziness, nausea, collapse, difficulty breathing, loss of consciousness and even death.
Protective measures: If it accidentally touches the eyes and**, rinse immediately with plenty of water and consult a doctor**.
Trichloroacetic acid(trichloroacetic acid，tca）
Use and harm: Macromolecular precipitant, which can be used for concentration or desalting of protein samples, has a slight special pungent odor. It is highly corrosive. TCA can also effectively disrupt cell and nuclear membranes and purify DNA, making it suitable for subsequent molecular biology experiments, such as PCR, restriction digestion, and sequencing. Inhalation and inhalation will be poisonous, strong irritation to ** and tissues, and extremely corrosive.
Protective measures: Operators must wear protective equipment to prevent contact with the human body. In case of accidental contact with eyes and**, rinse immediately with plenty of water and consult a doctor**.
Diethyl pyroate(Diethy Pyrocarbonate, or DEPC).
Uses and hazards: DEPC is used to dissolve RNA, can inactivate various proteins, is a strong inhibitor of RNA enzymes, and is a potential carcinogen. DEPC can react with amines and sulfhydryl groups, so reagents containing TRIS and DTT cannot be treated with DEPC.
Precautions: Operate in a fume hood and avoid contact**. DEPC is not very toxic, but it is the strongest after inhalation, and a mask must be worn when using it. If it gets on your hands, rinse immediately with plenty of water.
Ethidium bromide(Ethidium Bromide, abbreviated as EB).
Uses and hazards: Fluorescent dyes commonly used for nucleic acid staining in agarose gel electrophoresis to observe DNA in agarose and polyacrylamide gels. But EB is a strong mutagenage, highly carcinogenic, and evaporates at 60-70 degrees Celsius. Therefore, extreme care needs to be taken when using it and appropriate safety measures should be taken to reduce the risk of exposure.
Protective measures: Appropriate personal protective equipment, including a lab coat, gloves, and goggles, must be worn when handling EB to reduce the risk of exposure and inhalation. Due to the toxicity of ethidium bromide, after the experiment, the EB-containing solution should be purified and disposed of to avoid polluting the environment and endangering human health.
Bromophenol blue
Uses and hazards: 1% bromophenol blue is often used as an indicator dye in electrophoresis. **Absorption can cause damage.
Precautions: Handle in a fume hood and wear appropriate personal protective equipment, including gloves and goggles.
Dithiothreitol(Dithiothreitol, or DTT).
Uses and hazards: DTT is a small molecule reducing agent, often used for the reduction of disulfide bonds in proteins, which can be used to prevent the formation of intramolecular or intermolecular disulfide bonds between cysteines in proteins. It will emit an unpleasant odor. It can be harmful to health due to inhalation, ingestion, or absorption.
Precautions: When working with solid or highly concentrated stock liquids, gloves and goggles should be worn and operated in a fume hood.
Coomassie brilliant blue
Use and harm: It is proportional to the protein concentration within a certain range, so it can be used for the quantitative determination of protein. Inhalation, ingestion, and absorption can cause damage.
Precautions: Safe operating procedures should be followed when used to reduce exposure and inhalation of chemicals. Wear appropriate personal protective equipment, including gloves and goggles.
Acrylamide(acrylamide)
Uses and hazards: Acrylamide is a white crystalline chemical that is the raw material for the production of polyacrylamide. Acrylamide is a moderately toxic substance that can enter the human body through **absorption or respiratory tract. The harm of acrylamide is mainly to cause neurotoxicity, as well as reproductive and developmental toxicity. Neurotoxicity is characterized by degenerative changes in peripheral nerves and brain areas involved in Xi, memory, and other cognitive functions, and tests have also shown that acrylamide is a possible carcinogen, cumulative toxicity, and is not easily detoxified.
Precautions: During operation, avoid inhaling unpolymerized acrylamide vapors. Wear appropriate personal protective equipment, including respirators, and gloves to reduce the risk of exposure. Make sure to operate in a well-ventilated laboratory.
Tetramethylethylenediamine(n,n,n',n'-Tetramethylethylenediamine (TEMED).
Uses and hazards: Temed is a colorless and transparent liquid, with a slight fishy odor, is a strong nerve agent, can cause respiratory irritation and nervous system damage. In molecular biology, it can be used to formulate SDS-PAGE gels: catalyze the generation of free radicals by APS, thereby accelerating the polymerization of polyacrylamide gels and being used as a coagulant.
Protective measures: to avoid its volatilization when using, you can prepare 1%-5% ammonia for standby, ** can be rinsed with a large amount of water and dilute ammonia water after being stained Protective measures: avoid direct contact ** and eyes, wear suitable gloves and safety goggles. In addition, TEMED should be handled with care to reduce volatile exposure. Prevents aspiration, quick operation, sealed storage.
Sodium lauryl sulfate(Sodium Dodecyl Sulfate, SDS).
Use and harm: SDS is an anionic surfactant, which has a strong destructive power, which can basically dissolve all proteins and destroy their natural conformational structure. SDS and protein molecules are combined with 1The ratio of 4:1 can effectively cover the charge of the protein itself. SDS is toxic and is an irritant that can cause serious damage to the eyes. It can damage the health of the body due to inhalation, ingestion, or absorption.
Precautions: Wear appropriate gloves and safety goggles. Operate in a chemical fume hood and avoid inhaling its powder.
Ammonium persulfate(Ammonium Persulphate, APS).
Use and harm: It is used to generate free radicals in WB glue, and free radicals trigger acrylamide polymerizationAPS is extremely harmful to mucous membranes and upper respiratory tract tissues, eyes and **, and can be fatal if inhaled.
Protective measures: Appropriate gloves, safety goggles and protective clothing should be worn during operation. Always operate in a fume hood and wash your hands promptly after operation.
Phenylmethylsulfonyl fluoride (PMSF).
Use and harm: PMSF is a highly toxic cholinesterase inhibitor, which can inhibit the activity of a variety of proteases. But it is very destructive to the mucous membranes of the respiratory tract, the eyes and **. Can be fatal by inhalation, ingestion, or absorption.
Precautions: Wear appropriate gloves and safety glasses and use them in a chemical fume hood at all times. Immediately after contact with the human body, rinse your eyes with plenty of water or**, and discard the contaminated work clothes.
Sodium azide(sodium azide，nan3）
Uses and Hazards: Sodium azide is very toxic, it can block the cytochrome electron transport system. Solutions containing sodium azide should be clearly labeled. It can be detrimental to health due to inhalation, ingestion, or absorption.
Precautions: Wear appropriate gloves and safety goggles, and take extra care when handling.
Silver nitrate(silver nitrate，agno3)
Use and harm: used for protein staining after electrophoresis (silver staining method);Silver nitrate is a strong oxidizing agent, corrosive (black spots will appear on contact) and polluting, which can cause ** and eye burns. Ingestion of silver nitrate can cause severe abdominal pain, vomiting, bloody stools, and even gastrointestinal perforation. The lethal dose in adults is about 10 grams. Half lethal dose (mouse, oral) 50 mg kg;Contact with alcohol produces**.
Precautions: Avoid inhalation, wear appropriate gloves and safety goggles, operate in a fume hood, away from heat, sparks and open flames. In case of accidental contact with eyes and**, rinse immediately with plenty of water and consult a doctor**.
Glacial acetic acid(aceticacid，ch3cooh)
Use and harm: Prepare protein fixative solution with ethanol in silver staining;Glacial acetic acid is a highly corrosive, flammable liquid that can be irritating to the nose, throat and respiratory tract if inhaled. It has a strong irritating effect on the eyes. **Contact, erythema appears in mild cases, and chemical burns in severe cases. Accidental ingestion of concentrated acetic acid can cause erosion in the oral cavity and digestive tract, and in severe cases, it can cause death due to shock. It is flammable, and its vapor is mixed with air to form a first-class mixture.
Precautions: Avoid inhalation, wear appropriate gloves and safety goggles, operate in a fume hood, away from heat, sparks and open flames. In case of accidental contact with eyes and**, rinse immediately with plenty of water and consult a doctor**.
Xylene
Use and hazard: flammable, high concentration has anesthetic effect. Inhalation, ingestion, and absorption can cause harm.
Precautions: Avoid inhalation, wear appropriate gloves and safety goggles, operate in a fume hood, away from heat, sparks and open flames.
Paraformaldehyde(paraformaldehyde，pom)
Use and harm: used for tissue fixation, volatile and highly toxic. It is easily absorbed through ** and has serious damage to **, eyes, mucous membranes and upper respiratory tract.
Precautions: Avoid inhalation, wear appropriate gloves and safety goggles, and operate in a fume hood.
Formaldehyde(formaldehyde，hcho)
Use and harm: Formaldehyde has antiseptic and sterilizing properties, which can be used to soak biological specimens, disinfect seeds, etc. Formaldehyde is highly toxic and volatile, and is also a carcinogenic agent. It is easily absorbed through ** and has an irritating and damaging effect on the eyes, mucous membranes and upper respiratory tract.
Protective measures: Avoid inhaling its volatile vapor mist. Wear appropriate gloves and safety glasses. Always operate inside a chemical fume hood. Keep away from heat, sparks and open flames.
Chloroform(trichloromethane，chcl3)
Uses and Hazards: Chloroform can be used as an extractant for the separation and extraction of organic matter from biological samplesIt can also be used as an inhibitor to inhibit the activity of certain enzymes in biological reactions. Chloroform is a volatile organic solvent that can be a health hazard when exposed to long-term or high concentrations. It is toxic to the central nervous system. Chloroform has an irritating effect on **, eyes, mucous membranes and respiratory tract. It is a carcinogen that can damage the liver and kidneys. Volatile, chloroform should avoid inhaling volatile gases.
Precautions: When using, it is necessary to take appropriate safety measures, wear appropriate gloves and safety goggles, and operate in a fume hood.
triton x-100
Uses and Hazards: Triton X-100 is a mild detergent that is often used as an additive to stabilize proteins, especially membrane proteins. It can improve the permeability of eukaryotic cell membranes. Causes severe eye irritation and burns. Inhalation, ingestion,** can cause harm.
Protective measures: Appropriate safety measures need to be taken, appropriate gloves and safety goggles should be worn, and operation in a fume hood.
Giemsa(giemsa)
Uses and hazards: Giemsa stain solution is suitable for staining blood smear specimens, blood cells, malaria parasites, rickettsia, bone marrow cells, spinal cord cells, etc. Giemsa stain is toxic and can cause blindness and even death if inhaled by the human body.
Precautions: Wear appropriate gloves and safety goggles. Operate in a chemical fume hood and avoid inhaling its powder.
Isotopes
Uses and hazards: Isotope labeling is also called isotope tracing;It can be used to track the movement and change of substances. Isotopes can be divided into stable isotopes and radioactive isotopes. Stable isotopes do not decay, are not radioactive, and do not cause adverse effects on health;Radioactive isotopes have a certain half-life and are unstable isotopes that are radioactive and harmful to the human body.
Protective measures: take necessary radioprotective measures and safety measures, and try to avoid violent reactions such as high temperature and high pressure.
In addition to the chemical reagents introduced above, contact with microorganisms in daily scientific research work is also unavoidable, and when using these microorganisms for experimental research, it is necessary to operate in accordance with relevant regulations to ensure the safety of experimenters and the environment.
1) Escherichia coli.
Commonly known as Escherichia coli, it can be a conditional pathogen such as the presence of a foreign body (e.g., a urinary catheter), host injury, or breakage of a normally sterile site that causes fecal invasion or high concentrations of mixed bacteria, which can cause extraintestinal infection. Certain strains can cause diarrhea. The agar plates inoculated and cultured by microbial testing should be sterilized by pressure for 30min, and the agar should be discarded while hot.
2) Staphylococcus aureus.
Gram-negative bacteria are an important pathogenic bacteria in humans, mainly causing purulent inflammation, and can also cause pneumonia, pseudomembranous enteritis, pericarditis, etc., and even systemic infections such as sepsis and sepsis. The agar plates inoculated and cultured by microbial testing should be sterilized by pressure for 30min, and the agar should be discarded while hot.
In addition, the state divides pathogenic microbiology laboratories into Level 1, Level 2, and Level 4 on the basis of the level of biosecurity protection of pathogenic microbiology laboratories and in accordance with the provisions of the national standards for laboratory biosecurity. Among them, the level 1 biosafety laboratory has the lowest requirements for biosafety isolation, and the fourth level is the highest.
When entering the pathogenic microbiology laboratory, you should do a good job of personal protection, such as wearing masks, eye protection, work clothes, protective clothing, etc.
In addition, in order to achieve efficient gene expression and regulation, a class of expression tools - medical pseudoviruses are often used when conducting gene function research, which is modified from wild viruses to remove the pathogenic elements of wild viruses to ensure their safety, and their genomes are split to retain their ability to infect cells. The most commonly used medical pseudovirus tools in laboratories are lentivirus, adenovirus, and adeno-associated virus, and these tools should also be used in strict accordance with the relevant standards.
Lentiviral vector is a single-stranded RNA virus, which is a gene vector developed on the basis of human immunodeficiency virus (HIV), which is capable of infecting ** cells and non** cells. Lentiviral vectors commonly used in laboratories are artificially modified to remove all genes containing coat proteins from the genetic material, thus ensuring that the exogenous genes are integrated into the genome without the elements required to express the viral coat. Theoretically harmless to humans, but the virus is still potentially biologically hazardous, and we recommend that lentivirus-related experiments should be performed in a biosafety cabinet (BL-2 class).
It is recommended that you use lentivirus for experiments in strict accordance with the following standards:
1) Wear a lab coat, mask and gloves when handling the virus, and try not to expose your hands and arms
2) Be careful of virus splashing when handling viruses, if there is virus contamination on the ultra-clean workbench during operation, please wipe it with 70% ethanol and 1% SDS solution immediately. Pipette heads, centrifuge tubes, culture plates, and culture mediums that have been exposed to the virus should be soaked in 84 disinfectant solution and disposed of uniformly.
3) If centrifugation is required, use a well-sealed centrifuge tube, and if necessary, seal with parafilm and centrifuge.
4) Virus-related wastes need to be specially collected and treated after high temperature sterilization.
5) Wash your hands with soap after the experiment.
Adenoviral vectors are non-enveloped, linear double-stranded DNA viruses that are capable of infecting both differentiated and undifferentiated cells without integration into the host genome. The first-generation adenoviral vector deletes the E1 and E3 regions, which are essential for viral replication, and therefore requires transformation of 293 cells that can constitutively express the E1 region protein. In addition, because infection usually causes only mild illness, adenovirus is considered a safe viral vector and is widely used in genetic**, oncolytic virus, and vector virus vaccines. Considering that viruses are still potentially biologically dangerous, it is recommended that you use adenovirus in your experiments with strict reference to the following criteria:
1) Wear a lab coat, mask and gloves when handling the virus, and try not to expose your hands and arms
2) Be careful of virus splashing when handling viruses, if there is virus contamination on the ultra-clean workbench during operation, please wipe it with 70% ethanol and 1% SDS solution immediately. Pipette heads, centrifuge tubes, culture plates, and culture mediums that have been exposed to the virus should be soaked in 84 disinfectant solution and disposed of uniformly.
3) If centrifugation is required, use a well-sealed centrifuge tube, and if necessary, seal with parafilm and centrifuge.
4) Virus-related wastes need to be specially collected and treated after high temperature sterilization.
5) Wash your hands with soap after the experiment.
Adeno-associated virus is the simplest, non-enveloped single-stranded DNA virus ever discovered. a**It cannot replicate on its own, and must rely on other viruses for replication. Recombinant adeno-associated virus is an engineered A** vector, which rejects all the encoding protein REP or CAP gene sequences of the A** genome, and only retains the trans DNA sequence (i.e., ITR) as a packaging signal at both ends. More than 80% of people carry a**, which has not been found to be associated with any disease, and has very low immunogenicity.
In addition, according to the Biosafety Management Regulations of the National Institutes of Health, DNA and gene vectors used for genes are divided into four risk grades based on their relative pathogenicity to health**.
Adeno-associated virus (A**) type 1-4, replication-defective recombinant A** (the infected body neither encodes an underlying oncogene nor produces a toxin molecule), is currently the only viral vector belonging to the RG1 class. Other commonly used adenoviruses, lentiviruses, herpes viruses, and poxviruses belong to the RG2 category, and retroviruses belong to the RG3 category.
Finally, Xiao Heng once again reminded everyone: the road of scientific research is long, and I will seek safety first!