Abstract
Purpose :
Our new drug carrier platform based on lipid-modified DNA nanoparticles (NPs) was already presented in previous years. DNA-NPs are able to bind to the eye and can be used as carrier platforms for the enhanced delivery of eye medication. By binding the drugs to the NP using different methods, we create better adhesion and thereby a drug release system that can be used to tailor the liberation of the drug, resulting in an improved pharmacokinetic profile of the drug. First experiments of kanamycin conjugated DNA-NPs showed a prolonged adherence of kanamycin to ex-vivo human and in-vivo rat corneas.
Methods :
In this study, kanamycin was conjugated to DNA-based NPs via aptamers (Kan-NP). Loaded NPs and the kanamycin itself were used to treat infected pig corneas. In one approach Kan-NP were dropped on ex-vivo pig corneas, then washed and transferred to petrifilms. Afterwards, E.coli colonies were applied onto the corneas, incubated at 37°C for 48h and the amount of colonies were counted. In the second approach, infectious bacteria (P. aeruginosa) were applied. Corneas were incubated until an infection was detectable. Next, treatment with Kan-NP and free kanamycin was started. After 3 days, different dilutions of the homogenized cornea were incubated on PIA plates. Furthermore, kanamycin loaded NPs, as well as the free drug, were dropped on rat and pig corneas. After different incubation periods corneas were homogenized and evaluated by liquid chromatography–mass spectrometry (LC-MS).
Results :
Both kanamycin alone and the loaded Kan-NPs were able to significantly decrease the amount of E.coli colonies compared to the vehicle control treated corneas. Even more, after an incubation time and subsequent washing of 5 min the NP delivered kanamycin is significantly better than the free kanamycin. This effect lasts until 60 min after incubation after which the NP delivered Kanamycin also lost its function. Also in the second approach, we could see less bacterial growth in Kan-NP treated corneas compare to kanamycin.
Conclusions :
Our data proofs the functionality of our DNA-based NP carrier system. With these results, we confirmed that the drugs are released from the NP and are still functional. Furthermore, due to the better adhesion our constructs are more efficient than the pristine drug. These findings are an important step for the future use of our NP platform for ocular drug delivery.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.