Low-Molecular-Weight Dipeptide Nanogel Containing Plasmonic Gold Nanoparticles for Drug Release Applications

The control of the release behavior of a drug by an external stimulus, controllability from outside the body, reduced toxicity, and other side effects can provide benefits in delivery systems used in cancer treatment. However, the preparation and development of systems that control the dosage of the periodically released drug by an external stimulus are still a clinically needed approach. Here, we developed near-infrared (NIR) laser-enabled peptide nanogel systems by preparing Fmoc-diphenylalanine (Fmoc-FF) nanogels with a simple dispersion approach and preparing gold nanoparticles (AuNPs) decorated or gold nanostars (AuNSs) embedded in this system. The morphological properties and sizes of the prepared AuNS-embedded and AuNP-decorated Fmoc-FF nanogels were investigated by dynamic light scattering (DLS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) methods. Structural and thermal characterizations were performed with attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and differential scanning calorimetry (DSC), respectively. Epirubicin (EPI) release behaviors of the prepared AuNS-embedded and AuNP-decorated Fmoc-FF nanogels were investigated under 808 nm NIR laser irradiation. In vitro cytotoxicity and genotoxicity behaviors of the prepared particles were examined, and their effects on laser control release behaviors were also evaluated. It has been observed that EPI release can be controlled by laser irradiation in nanogels containing embedded or decorated plasmonic gold nanoparticles. In addition, it is understood from the in vitro results that the prepared nanogel systems are more effective synergistically under 808 NIR laser irradiation. Our results showed that Fmoc-FF peptide nanogel systems prepared as plasmonic AuNP embedded or decorated have great potential for controlled drug delivery systems.