6 Laboratory Sterilization Methods and How They Work

Learn why laboratory sterilization is essential for preventing environmental contamination of cell cultures and for safe disposal of cultures. The video introduces six common sterilization methods used in modern labs.

Use pressurized steam at 121°C to sterilize materials through protein hydrolysis and coagulation. Pressurized steam delivers heat 7 times more efficiently than regular water, allowing rapid heating and penetration of dense materials.

Sterilize materials using dry heat at temperatures up to 160°C, which kills microbes through oxidation rather than protein hydrolysis. This method requires higher temperatures and longer times compared to autoclaving.

Pass solutions through 0.2 micrometer membrane filters made from cellulose esters to remove bacteria without heating. Note that viruses and phages pass through these filters, so filtration alone cannot guarantee complete sterilization.

Use ethanol or isopropanol diluted to 60-90% with water to denature microbial proteins on surfaces. Remember these solvents are ineffective against bacterial spores.

Use UV light for small areas like laminar flow hoods, or X-rays and gamma rays for large-scale cold sterilization of heat-sensitive plastics like syringes. All radiation types damage DNA to eliminate microbes.

Apply ethylene oxide gas to sterilize heat or moisture-sensitive equipment such as medical catheters and stents by preventing cell metabolism through alkylation. Aerate equipment after sterilization to remove residue, as ethylene oxide is highly toxic.