1. Department of Chemistry, Faculty of ScienceChulalongkorn University Bangkok 10330 Thailand
2. Faculty of Chemistry, Materials and BioengineeringKansai University Osaka 564‐0836 Japan
3. Department of Microbiology and Research Unit on Oral Microbiology and Immunology, Faculty of DentistryChulalongkorn University Bangkok 10330 Thailand
4. Center of Excellence in Materials and Bio‐interfacesChulalongkorn University Bangkok 10330 Thailand