Cell Culture Techniques Flashcards
What is a cell/tissue culture?
Laboratory method (in vitro) by which cells are grown under controlled conditions outside their natural environment.
What are some advantages of cell cultures?
- Control physiochemical environment and physiological conditions
- Control micro-environment - Cells easily identified and visualised (staining and imaging techniques)
- Cells can be stored in liquid nitrogen for long periods
- Cells easily quantified
- Reduces use of animals in experiments
- Cheaper to maintain than growing mice
Give examples of physiochemical controls.
pH, temperature, osmolarity
Give examples of physiological factors
matrix, cell to cell interaction and cell substrate attachment
What is cryopreservation?
Storing cells in liquid nitrogen
What 2 types of cells can be cultured?
Primary tissue cells or immortalised cell lines
What are primary tissue cells?
Cells taken directly from patients/tissues and cultured in vitro to stimulate body environment
What are the characteristics of primary tissue cells?
- useful if directly from patient tissue - personalised medicine
- finite lifespan but retains cell identity
- cells carry out normal functions (as if still in tissue)
- varied donor (not just from one person)
What is immortalised cell lines?
Single donor cell line that has infinite lifespan
Advantages and disadvantages to immortalised cell lines
- infinite lifespan so can maintain for long but loses cell specificity
- from vial (not patient) with many mutations and clonal selections
- single donor studied repeatedly
What 2 ways can primary tissue cells be isolated by (how to extract cells)?
- Cells allowed to migrate out of explant naturally (only in some cells)
- Mechanical (biopsy) and/or enzymatic dissociation (purification via cell surface markers)
Give examples of mechanical dissociation
Mincing, sieving, pipetting
Give examples of enzymatic dissociation
Trypsin, collagenase, hyaluridanse, protease, DNAase
What is an explant
Transfer living cells/tissues to nutrient medium
Which primary tissue cell does not need to be disaggregated? and how is it isolated?
Haematopoietic cells - they are already individual cells circulating in blood.
Density centrifugation (specific cells separated into layers) followed by either immuno purification or FACS so cells of interest is separated
What are the disadvantages of primary tissue cells?
- Patient variation = difficult to reproduce results
- Limited number and high cost
- Finite lifespan and hard to maintain (due to specific medium)
- Difficult molecular manipulation (e.g. CRISPR to modify cells)
- Phenotypic instability (diff characteristics)
- Susceptible / variable contamination
Why might immortalised cell lines be better than primary tissue cells?
Good reproducibility Good model for basic science Phenotypically stable Easy to grow Limitless - available
Which 2 ways are “immortalised” cell lines are produced?
- Isolated from cancerous tissues (HeLa cells)
- Immortalisation of healthy primary cultures through genetic manipulation (transfection with either viral oncogenes that inhibit tumour suppressor genes or with telomerase gene introduction)