Ultraviolet (UV) radiation, particularly UV-C radiation (wavelength range: 200–280 nm), is widely used for sterilization and disinfection due to its powerful germicidal properties. It can effectively kill or inactivate microorganisms such as bacteria, viruses, fungi, and protozoa by damaging their genetic material.
Mechanism of Action:
- UV-C light penetrates microbial cells and is absorbed by DNA and RNA.
- It causes the formation of thymine dimers in DNA, which disrupt replication and transcription.
- This damage either kills the organism or prevents it from reproducing, effectively rendering it harmless.
Applications of UV Sterilization:
1. Medical and Laboratory Equipment
- Used to sterilize surgical tools, work surfaces, and laboratory instruments.
- UV chambers or cabinets expose items to UV-C for a specific duration.
2. Hospital Rooms and Air Purification
- UV-C lamps are installed in operating rooms, ICUs, or HVAC systems to reduce airborne and surface pathogens.
- Helps prevent hospital-acquired infections (HAIs).
3. Water Purification
- UV disinfection systems are used in drinking water treatment plants, bottled water production, and aquariums.
- UV-C light neutralizes harmful microbes without adding chemicals.
4. Food and Beverage Industry
- Used to disinfect surfaces, packaging, and liquids like juices and milk, especially in non-thermal pasteurization.
5. Public and Personal Use
- Portable UV sanitizers for phones, masks, toothbrushes, etc.
- UV lamps used in air purifiers, restrooms, and public transport for surface disinfection.
Advantages:
- Chemical-free: No residue or toxic byproducts.
- Fast and efficient: Acts within seconds to minutes.
- Broad-spectrum: Effective against bacteria, viruses, and spores.
Limitations and Safety:
- UV-C is harmful to skin and eyes—exposure must be avoided.
- Effectiveness depends on exposure time, distance, wavelength, and cleanliness of surfaces.
- Shadowed or dirty areas may not be fully disinfected.