Application of Nano TiO2 as Antimicrobial Agents

Megha R

ESBE Self Study

Nano TiO2

• Photocatalytic properties, high photoreactivity• Food grade• Antimicrobial properties• Strong oxidising power in UV light• Applications– White pigment in paint and food colouring– Effluent treatment– Coating on PV cells

Antimicrobial properties

• Act against Gram positive and gram negative strains of bacteria as well as fungi

• Non-toxic, environment friendly and possess non contact biocidal properties

• Inhibits reproduction ability of bacteria by arresting growth in lag phase

• Can also decompose phospholipid part of cell walls and completely degrade microbial cells

Antimicrobial properties

• Also decreases the expression of co-enzyme related activities

• Lowers the ability to transport iron and phosphorous

• Damages DNA with hydroxyl ions

Applications

Food Packaging Material• TiO2 nanoparticles coated on plastics can be used as

packaging material for foods and other sterile coverings• Due to antimicrobial and non contact properties• Successful in extending shelf, quality and safety assurance• Can be coated or adsorbed onto polymer films or used as

sachets

Applications

Coatings and Paints• Coated onto polymer films and tested for microbial activity• Tested for action against Escherichia coli (E. coli),

Staphylococcus aureus, and Pseudomonas putida

Applications

Coatings and Paints• Can be coated onto high and low density polyethylene (LDPE

and HDPE)• Forms stable nanocomposite without altering properties of

either polymer or nanomaterial• Can also be doped with metals such Ag and Cu to increase

bacteriocidal properties and wavelength range • New antimicrobial interior paints developed – coated on walls

and absorb light from fluorescent bulbs and undermines bacterial growth

Applications

Photoinduced hydrophilic coatings and self-cleaning devices

• High hydrophilcity - self cleaning effect• Photo-catalysis helps in breaking down accumulated dirt and

organic matter removing colouration and odour• Biocidal properties prevent build-up algae, fungus and mould• Gens Nano TiO2 coating - special coating developed for wall

exteriors• Used in self cleaning textiles

Photocatalytic Action

Photocatalytic Action

• Anatase TiO2 used which has a bandgap of 3.2eV

• On absorption of photons of that bandgap electron and hole pairs are generated

• Can either recombine or move to the surface • At the surface, react with adsorbed electron

acceptor and donor

Photocatalytic Action

• Water and oxygen act as electron donor and acceptor to produce hydroxyl ions and superoxide ions

• The products, combined with holes, are powerful oxidising agents

References

• Understanding the antimicrobial mechanism of TiO2-based nanocomposite films in a pathogenic bacterium

• http://www.mchnanosolutions.com/• http://www.sciencedirect.com/• Antimicrobial Activity of TiO2 Nanoparticle-

Coated Film for Potential Food Packaging Applications