Efficacy, bioavailability, and intracellular delivery of nanoparticle based drug encapsulated carbon for antiviral therapy.

Topical therapies with improved antiviral efficacy, bioavailability, and safety profiles are needed to combat blindness caused by herpes simplex virus type-1 (HSV-1) eye infections. Our previous work demonstrated that micron-sized high porosity activated carbon (HPAC) particles loaded with acyclovir (ACV), termed drug-encapsulated carbon (DECON), showed superior topical efficacy to ACV alone while reducing dosage frequency. Here, we advance our findings by utilizing a nanoparticle-based DECON (nanoDECON), which enhances cell permeability while maintaining DECON's nontoxic, cost-effective, and nonimmunogenic properties. Our assays demonstrate nanoDECON's low toxicity and nearly 100% loading of nucleoside analogs acyclovir, ganciclovir, and penciclovir. Drug release studies indicate that nanoDECON stably encapsulates these drugs with minimal passive release over 48 hours. Furthermore, antiviral studies with HSV-1-infected human corneal epithelial (HCE) cells show excellent antiviral activity at concentrations as low as 25 µg/mL. FITC-loaded nanoDECON illustrates a novel ability of this agent to deliver payloads into the cytoplasm and nucleus, as evidenced by confocal imaging. However, attempts to use nanoDECON for plasmid DNA delivery indicated poorer loading efficiency and a lack of GFP expression.