Gepi based hetero-functional peptides for imaging of glioblastoma cancer stem cells

Gold nanoparticles (AuNPs) are proven to have high potentials in nano-medical fields. Due to their unique optical properties as well as high electron density, the hybrid gold nanoparticles can be efficiently used as targeting and contrast bioimaging and diagnostic nanoprobes. They also offer to be used to deliver thermal energy for therapeutic effects. However, functionalization of gold nanoparticles becomes critical for their stable and robust effects to be delivered in the biological systems. Recognition of biological entities requires coupling biological functions onto the gold nanoparticles, which has been done through multistep chemical and/or physical methods usually involving relatively stringent conditions and harsh reducing agents. Here, engineered peptide based self-assembly functionalization method was used to create functionalized AuNPs for glioblastoma cancer stem cell specific targeting. Designed peptide sequences included both glioma cell binding peptide and gold binding peptide which was able to self-assemble onto AuNP surfaces. The gold binding peptide sequence was previously selected using a combinatorial FliTrx peptide library. Peptides were tested for their effectiveness using 15nm AuNPs by localized surface plasmon resonance spectroscopy (LSPR). Spectral scanning data was evaluated by GraphPad Prism 6.0 software. The functionalized gold nanoparticles were delivered to NIH3T3, U-87 MG and GBM CSCs cells. AlamarBlue assays were used to show cytotoxicity effect of functionalized AuNP on cell lines. Cell spreading assay was used to test cell binding character of hetero-functional peptides with respect to cell lines. Results demonstrate that, stable, chimeric peptide-functionalized AuNPs were developed for specific cell targeting. It was also shown that hetero-functional peptides had cell selectivity for binding. Our developed hetero-functional peptide strategy is a promising approach not only for cellular imaging, but also for tumor site-specific drug delivery, potentially reducing the side effects for chemotherapeutics dependent upon on direct cellular uptake, as well as nanoparticle-mediated hyperthermia therapy for GBM cancer patients.