Battling bacteria with yellow spice and blue light – a matter of ammunition delivery
As the microbial resistance towards antibiotics increases, other methods are developed to combat localized infections in e.g. the oral cavity. A treatment consisting of a light-absorbing compound, curcumin, a substance found in curry, combined with blue light irradiation causes oxidative or other photodamage to the microbes. An efficient and clinically acceptable treatment requires drug formulation or carrier: curcumin must be “wrapped” and made available, or delivered, to the bacteria. Different types of nano-sized drug carriers were used to target and release curcumin to “free” and unattached (planktonic) bacteria and to a biofilm consisting of the same bacteria. While the photokilling effect on planktonic bacteria was dependent on the type of drug carrier and light dose to eradicate the bacteria, the biofilm was overall less sensitive. The two forms of bacteria must be attacked with different drug-formulation strategies.