Anti-microbial properties of hybrid sol-gel coatings

 
Common contact surfaces such as door handles or handrails play an important role in the spread of infections. Antimicrobial coatings can be used to minimize the pathogen load on such contact surfaces. The used coatings should have a high level of substrate compatibility so that they can be applied to as many materials as possible. Inorganic-organic sol-gel hybrid systems can be used for this purpose. This coating matrices are quick, inexpensive and easy to produce. They can be easily adapted to different tasks and are also easy to handle and non-toxic. By combining such a sol-gel matrix with an antimicrobial component, antimicrobially effective coatings can be created. As antimicrobial components silver doted zinc oxide nanoparticles can be used. The particles were synthesized in an ethanolic solution and immobilized in the sol-gel matrix. The chosen route of synthesis made it easy to incorporate the nanoparticles into the hardener of the coating mixture, without any undesirable effects for the resulting coating. The mixture was applied to the metal substrate using pipettes and the resulting coating was characterized using various tests. During analysis, it was found that the particle immobilization did not affect the drying of the sol-gel layer. Using contact angle measurements, it was determined that the sol-gel surfaces were hydrophobic and had approximately the same surface energies as the frequently used plastics PET or polypropylene. Accordingly, no problems were expected in the use of the coatings due to the surface behavior. Antimicrobial properties. The antibacterial properties were successfully tested using the disk diffusion test against the organisms Escherichia coli and Bacillus subtilis. For further development, the adhesive strength of the coating to the substrate is to be improved, for example by roughening the substrate before coating or using different application methods.