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Cell Culture Environment. How to grow a plant ?. Water. Soil. Air (CO 2 and O 2 ). Nutrition. Water : Culture medium . Soil : substrate for cell growth . Air (CO 2 and O 2 ) : Air in incubation chamber. Nutrition : growth supplement. Culture Medium Functions of culture medium:
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How to grow a plant ? Water Soil Air (CO2 and O2 ) Nutrition
Water : Culture medium Soil : substrate for cell growth Air (CO2 and O2 ) : Air in incubation chamber Nutrition : growth supplement
Culture Medium • Functions of culture medium: • 1. Maintain the pH • 2. Maintain the osmolarity • 3. Provide nutrient • 4. Provide energy
Basic components of cell culture environment • The in vitro environment must meet the • fundamental physiological requirements of the cell • 1. Culture medium • 2 . Physiological factors • pH 7.27.5 • osmolarity 280320 mOsmol/kg • CO2 25% in air • temperature 35oC-37oC • 3. Stationary versus dynamic media • supply enough • replenish at proper time • vol. 0.20.3ml/cm2
A complete culture media: 1. A basal medium specifies for all cellular requirements 2. A set of components that specify other cellular requirements and permit growth of cells in the basal medium
Basic Energy source for cell growth Carbohydrate sugar starch
Basal Medium • Types of basal medium • 1.Eagles medium and derivative • e.g. BME, EMEM, AMEM, GMEM, JMEM • 2. Media designed at Roswell Park • Memorial Institute ( RPMI) • e.g.RPMI 1629, RPMI 1630, RPMI1640
3. Basal medium designed for use after serum supplement e.g. Fischer’s Lieboutz, Trowell, Will 4.Basal medium designed for serum-free formulation e.g. CMRL 1060 Ham’s F10 and derivatives TC199 and derivatives NCTC Waymouth
5. For insects culture • e.g. Grace’s medium • Schneider’s medium • Mitsuhashi and maramerosch medium • IPL-41 medium • Chiu and black medium • D-22 medium
Basic components of the culture medium 1.Buffer system ß - glycerophosphate organic components e.g. HEPES, Tes, Bes 2. Energy Source glucose, maltose, sucrose, fructose, galactose, mannose 3. Amino Acid essential amino acid
4. Vitamins precursor for the cofactors e.g. biotin, choline, folic acid, nicotinic acid… • 5 . Hormones and growth factor • e.g. insulin, hydrocortisone, NGF, EGF • 6. Proteins and Polypeptide supplement with: • fetuin,-globulin, fibronectin, albumin, transferrin…. 7. Fatty acid and Lipid 8. Accessory e.g. Zn,Cu,Se….
10. Antibiotics factors to be considered: absence of cytoxisity broad anti-microbial spectrum accepted cost minimum tendency to induce formation of resistant micro- organism e.g. penicillin, streptomycin gentamycin.
Buffer System Bicarbonate buffer Recommended CO2 concentration and gas phase to use with common basal media basal medium NaHCO3 % of CO2 concentration gas phase Eagle’s MEM(Hank's salt) 4 grace’s (Hank salt ) 4 atmospheric IPL-41 (Hank salt ) 4 atmospheric TC100 (Hank salt ) 4 atmospheric Schneider’s (Hank salt ) 4 atmospheric IMDM 36 5 TC199 26 5 DMEM/Ham’sF12 29 5 RPMI1640 24 5 Ham’sF12 14 5 DMEM 44 10
Choice of basal medium • from literature • e.g. BME: for HeLa, L-cells, BHK, • primary culture of human rodent and avian • fibroblast • e.g. RPMI: for human haemopoietic cells • e.g. Iscove’s modified Dulbecco’s medium( IMDM): • for haemopoietic origin, growth and • differentiation of human and murine primary • bone marrow culture • e.g. sf9,sf21: for Drosophilla and insect culture
Preparation of basal medium • Factors to be considered: • Avoid contamination • Use pure water • Use analytical chemicals • Glassware used must be cleaned
Equipment for preparation of media: • High purity chemicals and biologicals • Good analytical balance • Hot plate with magnetic stirrer Volumetric flasks of various volume pH meter • Osmometer • Autoclave and membrane filtrate • medium kept at 4oC • storage: • storage should not be over 3 months
Serum Why use serum ? Advantages of using serum • Serum represent a cocktail of most of the factors • Required for cell proliferation and maintenance. • 3. An universal growth supplement which is effective • with most cells. • 4. Serum buffers the cell culture system against a variety • of perturbation
Types of serum 1. FBS ( Fetal Bovine serum) from abattoir 2. Horse serum, calf serum from donor ) should pass virus test)
Constituents of serum • 1.Growth factors ; 5—30 kDa polypeptide • 2.Albumin • a. a carrier protein • b. carry thyroxin and metal • c. pH buffering 3. Transferrin-ion transport protein • 4. Anti-protease: prevent cell from proteolytic damage • a1-trypsin • b2-macroglobulin
Nutritional and protective factors which may be supplied by serum • 1.Specific growth factors-- • EGF,PDGF,IGF,FGF, IL-1,IL-6 • 2.Trace elements-- • Iron, Zinc, Selenium • ( Co,Cu,I,Mn,Mo,Cr,Ni,V,As,Si,F,Sn) • 3. Lipids-- cholesterol, linoleic acid, steroids • 4. Polyamines--putrescine, ornithin, spermidine
5. Attachment factors-- fibronectin, fetuin, Laminin • 6. Mechanical protection– albumin • 7. Buffering capacity– albumin • 8. Neutralization of toxic factors– albumin • 9. Transport of metals • transferrin/Fe+3, • ceruloplasmin/Cu+2 • 10.Protease inhibitors– antitrypsin,1macroglobulin
Potential problems with the use of serum • 1. Lack of reproducibility • Serum batches varies considerably • The presence of specific antibodies may • also affect the results • Serum may vary during the process of collection • Sterity
2. Risk of contamination • To prevent viral infection: • -propiolactone • -irradiation • heat inactivation( 56oC, 1hr) • 3. Availability and cost • 4. Influence of downstream process • difficulties in purifying proteins • serum protein 4—8 mg/ml, • recombinant protein---- 0.1ug/ml • difficulties in purifying monoclone antibody
Sourcing and selection of serum sourcing: dealing with reputable supplier selection: test the capability for growth on cheaper serum type test different batches of serum for growth performance test of cell growth from very low seeding test of cloning efficiency
Serum storage and use kept frozen, -20oC thaw rapidly, mix gently kept at 4oC once thawed
Replacement of serum in medium Replace by Controlled Process Serum Replacement ( CPSR) CPSR: derived from bovine plasma, lower endotoxin lower protein Replace by supplement or fortified serum fortified serum: supplement with mitogen, growth factor, hormones, proteins, protein stabilizer, trace elements
Serum Free medium A properly designed serum free medium is reproducible is not reliant on economics of the world cattle market simplifies down stream purification has no unknown factors e.g. viruses, growth inhibitors
The most common requirement of serum free medium e.g. polypeptide hormone, insulin, iron transport protein, transferrin • Supplement of serum free medium • e.g. steroid growth factors, trace elements reducing • agents, diamines, vitamins albumin complexes with • unsaturated fatty acid
Design of serum free media • Reduce serum gradually • Adding other components • Growth assay study in the presence of added • supplements for basal medium • Add components singly or in combination to a basal • medium in a step wise manner
Mechanical stabilizers and adhesion factors For suspension culture: To prevent shear damage: damage by air bubble, stirrer, shaker… improved by increase viscosity of the medium by adding: carboxy methyl cellulose ( viscosity modifier) and prolyvinylpyrrolidone( PVP), pluronic-F68 principles: formation of an interfacial structure of adsorbed molecule on cell surface)
Considerations : Energy source of basal medium Carrier of lipids Proper environment for metabolism Growth function of cells ( good buffering capacity) Good maintenance of electrolyte balance Fe+2---Zn+2----Cu+2trace elements: Na+,K+, Ca+2,Mg+2,Cl-,HPO4-2…..
For anchorage dependent cells • substrate treat with adhesive glycoprotein, fibronectin, laminin, chondrotin, serum spreading factors
Difficulties that may encountered with serum free medium • a. Design of a dedicated medium for each cell type • b. Culture condition become more critical • c. Serum free medium has a reduced capacity to inactivate • or absorb toxic materials
Selection of components e.g. transport protein,stabilizing proteins growth regulators, growth factors, attachment proteins, crude extracts, essential nutrient Practical hints on solubilizing specific components e.g. riboflavin, folic acid, tyrosine, cystein dissolve in NaOH e.g. fatty acid, lipids, fat soluble vitamins in alcohol solutions e.g. pluoronic F-68 soluble in cold water e.g. hypoxanthine heat to dissolve