SERS and integrative imaging upon internalization of quantum dots into human oral epithelial cells.
CdTe quantum dots (QDs) are widely used in bio-applications due to their size and highly efficient optical properties. However internalization mechanisms thereof for the variety of freshly extracted, not cultivated human cells and their specific molecular interactions remains an open topic for discussion. In this study, we assess the internalization mechanism of CdTe quantum dots (3.3 nm) capped with thioglycolic acid using non cultivated oral epithelial cells obtained from healthy donors. Naked gold nanoparticles (40 nm) were successfully used as nanosensors for surface-enhanced Raman spectroscopy to efficiently identify characteristic Raman peaks, providing new evidence indicating that the first interactions of these QDs with epithelial cells occurred preferentially with aromatic rings and amine groups of amino acid residues and glycans from trans-membrane proteins and cytoskeleton. Using an integrative combination of advanced imaging techniques, including ultra-high resolution SEM, high resolution STEM coupled with EDX spectroscopy together with the results obtained by Raman spectroscopy, it was determined that thioglycolic acid capped CdTe QDs are efficiently internalized into freshly extracted oral epithelial cells only by facilitated diffusion, distributed into cytoplasm and even within the cell nucleus in three minutes.
Centro de Investigaciones en Óptica, León Gto, 37150, México.
Elisa
E
Cepeda-Pérez
Centro de Investigaciones en Óptica, León Gto, 37150, México. tzarara@cio.mx.
Tzarara
T
López-Luke
Department of Physics and Astronomy, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX 78249, USA.
Germán
G
Plascencia-Villa
Centro de Investigaciones en Óptica, León Gto, 37150, México.
Leonardo
L
Perez-Mayen
Centro de Investigaciones en Óptica, León Gto, 37150, México.
Andrea
A
Ceja-Fdez
Department of Physics and Astronomy, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX 78249, USA.
Arturo
A
Ponce
The University of North Carolina-Charlotte, Department of Chemistry, 9201 University City Blvd., Charlotte, NC 28223, USA.
Juan
J
Vivero-Escoto
Centro de Investigaciones en Óptica, León Gto, 37150, México.
Elder
E
de la Rosa
D002478:Cells, Cultured; D004847:Epithelial Cells / Q000378:metabolism*; D006046:Gold; D006801:Humans; D008855:Microscopy, Electron, Scanning; D053758:Nanoparticles; D045663:Quantum Dots; D013059:Spectrum Analysis, Raman
D006046:Gold
Raman spectroscopy; SERS; epithelial cells; internalization; quantum dots