Differing Affinities of Gold Nanostars and Nanospheres toward HeLa and HepG2 Cells: Implications for Cancer Therapy

Gold nanoparticles have potential applications for the diagnosis and treatment of diseases due to their optical, sensing, and biological properties. Gold nanoparticles can be used as nanocarriers for the delivery of therapeutic agents or as nanoprobes to detect and monitor intracellular events. Studying their localization and properties in cells is an essential step toward developing nanoparticle products for in vivo use. Raman spectroscopy is a powerful and noninvasive method that we used to investigate how two different morphologies of gold particles, namely, nanostars and nanospheres, interact with cervical cancer cells (HeLa) and liver cancer cells (HepG2). Gold nanoparticles with branched structures are more effective in enhancing the Raman spectra for cell-relevant bands compared to nanospheres. Moreover, we observed a higher level of Raman enhancement of nanostars and nanospheres in HeLa cells compared to HepG2 cells, suggesting HeLa could uptake a higher level of both types under the same condition. We also used scanning electron microscopy and light microscopy to study the distribution of both types of nanoparticles in cells. Our results highlight the importance of nanomorphology in mediating changes in affinity of gold nanoparticles to different chemical structures in cells, which is important for developing nanomedicines for cancer therapy.