Functionalized diamond nanoparticles as a drug delivery system: Loading and release study

Abstract

AbstractUrinary tract infections (UTIs) are the second most common infectious disease in the United States, costing about $ 3.5 billion annually in treatment. As resistance to antibiotics becomes more common, a greater need for alternative treatments, including low‐dosage and cellular‐targeted antibiotic for treating UTIs, is required. Nanodiamond particles (NDPs) are attractive drug delivery platforms because of their stable, inert core and reactive but functionalizable surfaces. In addition, diamond nanoparticles show multiplicity of stable optical emission wavelengths offering a strong possibility that one or more of optical emissions can be used for optical transduction based biosensing applications. Recently and for the first time, a stable amoxicillin loading on purified and polyethyleneimine (PEI)‐functionalized NDPs has been demonstrated through our research. This research paper describes further study on the amoxicillin‐loaded NDPs by quantifying the amoxicillin loading on 6 and 25 nm NDPs and study of amoxicillin release at different pH as well as investigation of PEI release if any from these NDPs. As PEI is not detectable by UV–Vis spectrophotometer, we developed a technique of attaching copper ions to PEI polymer so that PEI can be traced and detected in the presence of amoxicillin by UV–Vis spectroscopy. The results showed that 1 g PEI‐functionalized 6 or 25 nm NDPs produced successful loading of 19 and 48 mg amoxicillin, respectively, as demonstrated by FTIR, dynamic light scattering (DLS) and UV–Vis characterization. The mechanism of drug release with respect to PEI is explained, and results show almost 85% of the drug is released in 20 hr in pH 4 at the body temperature. The results also demonstrated that there is no PEI release from the 25 nm NDPs, when the amoxicillin is released, which can be a therapeutic benefit property for drug delivery.