Hybrid biocompatible silica nanoparticles as theranostic agent

Introduction: Hybrid silica nanoparticles have attracted much attention owing to their potential biomedical applications in diagnostic and precision drug delivery for cancer detection and treatment. The inorganic silica core... [ view full abstract ]

Introduction: Hybrid silica nanoparticles have attracted much attention owing to their potential biomedical applications in diagnostic and precision drug delivery for cancer detection and treatment. The inorganic silica core can be used to transport cargo and impart properties such as fluorescence, whereas the polymeric shell can be used to convey water solubility, biocompatibility, long blood circulation times, and bioconjugation. The goal of our work is to develop “smart” hybrid nanoparticles (NPs) with theranostic (therapeutic + diagnostic) functionalities that carry a fluorescent dye for traceability and imaging, feature a mechanism for release control, and are able to accommodate large drug loads and deliver their cargo to the desired location. Here we focus on the preparation of fluorescent silica nanoparticles (SiNPs) with a poly(lactide-co-glycolide) (PLGA) biocompatible and biodegradable copolymer shell.

Method: We prepared monodisperse fluorescent SiNPs incorporating a perylenediimide (PDI) derivative in the silica network, and from the SiNPs external surface, a dense polymer shell of PLGA was grown by ring-opening polymerization (ROP), with different monomers ratio to modulate the degradation rate of the shell. The biocompatibility of the NPs was tested against MCF-7 human breast carcinoma cells. Cell viability and confocal studies were performed to assess the efficacy of the hybrid NPs.

Result & Discussion: The synthesized SiNPs were spherical and homogenous with an average diameter of ~31 nm which was confirmed by Transmission electron microscopy (TEM) and Dynamic Light Scattering (DLS). The increased diameter of the Hybrid NPs due to the formation of a PLGA shell on the surface of the silica core has been established by TEM and DLS. The cell viability (MTT assay) showed a high level of biocompatibility, and confocal images confirmed the time-dependent internalization of hybrid NPs into the MCF7 cells.

Acknowledgments: This work was partially supported by Fundação para a Ciência e a Tecnologia (FCT-Portugal) and COMPETE (FEDER), projects RECI/CTM-POL/0342/2012, UID/NAN/50024/2013, and PTDC/CTM-POL/3698/2014. R.R. thanks, Erasmus Mundus Experts Sustain Ph.D. grant.