Improved measurement of cellular uptake of gold nanorods based on flow cytometry

Gold nanoparticle-based Raman probes have the ability to significantly boost Raman spectra signals via Surface Enhanced Raman Scattering (SERS). However, accurately reflecting the precise localization and uptake of the metal probe within the intricate biological milieu becomes challenging as the probe remains within the system for an extended period. Therefore, there is a pressing need for an enhanced methodology to quantitatively assess the uptake of AuNPs in cellular environments. Flow cytometry emerges as a promising technique capable of evaluating intracellular AuNPs through efficient single-cell analysis of light scatter data obtained from a considerable population of live cells. In the conventional approach, the side scatter setting of flow cytometry is typically linked to the excitation light and employed for nanoparticle uptake detection. Nonetheless, this method presents limitations due to the suboptimal response of AuNPs to specific excitation wavelengths. To address this issue, a novel strategy is proposed. By aligning, to the fullest extent possible, the scattering absorption peak of the probe with the excitation light, achieved through the adjustment of the UV absorption peak position of the probe and selection of a red-shifted excitation light, the optical signal essential for flow cytometry based assessment of AuNPs uptake in HELA cells is markedly amplified. This innovative methodology facilitates accurate quantitative measurement of AuNPs uptake in instances where Raman molecular tracing proves inadequate. This study underlines the promising applications of flow cytometry in gauging AuNPs uptake within cancer cells and contributes valuable insights into advancing the comprehension of the mechanisms underpinning cellular uptake of AuNPs in SERS related investigations.