title: Aptamer-guided silver-gold bimetallic nanostructures with highly active surface-enhanced Raman scattering for specific detection and near-infrared photothermal therapy of human breast cancer cells.
abstract: The aptamer (S2.2)-guided Ag-Au nanostructures (aptamer-Ag-Au) have been synthesized by photoreduction and validated by ultraviolet-visible light (UV-vis) spectra and transmission electron microscopy (TEM) images. Differential interference contrast (DIC), fluorescence, and TEM images, and surface-enhanced Raman scattering (SERS) spectra indicated that the aptamer-Ag-Au nanostructures can target the surface of human breast cancer cells (MCF-7) with high affinity and specificity. This targeting is completed via the specific interaction between S2.2 aptamer (a 25-base oligonucleotide) and MUC1 mucin (a large transmembrane glycoprotein, whose expression increased at least 10-fold at MCF-7 cells in primary and metastatic breast cancers). However, the nanostructures cannot target HepG2 (human liver cancer cells) or MCF-10A cells (human normal breast epithelial cells), because these cells are MUC1-negative expressed. Moreover, the synthesized nanostructures exhibited a high SERS activity. Based on these results, a new assay for specifically detecting MCF-7 cells has been proposed. This assay can also discriminate MCF-7 cells from MCF-10A cells and different cancer cell lines, such as HepG2 cells. In addition, the aptamer-Ag-Au nanostructures have a high capability of adsorpting near-infrared (NIR) irradiation and are able to perform photothermal therapy of MCF-7 cells at a very low irradiation power density (0.25 W/cm(2)) without destroying the healthy cells and the surrounding normal tissue. Therefore, the proposed assay is significant for the diagnosis of tumors in their nascent stage. The synthesized nanostructures could offer a protocol to specifically recognize and sensitively detect the cancer cells, and would have great potential for application in the photothermal therapy of the cancers.
authors.affiliation: Jiangsu Key Laboratory of New Power Batteries, College of Chemistry and Materials Science, Nanjing Normal University, People's Republic of China.
authors.forename: Ping
authors.initials: P
authors.lastname: Wu
authors.forename: Yang
authors.initials: Y
authors.lastname: Gao
authors.forename: Hui
authors.initials: H
authors.lastname: Zhang
authors.forename: Chenxin
authors.initials: C
authors.lastname: Cai
mesh_terms: D052157:Aptamers, Nucleotide / Q000378:metabolism*; D001943:Breast Neoplasms / Q000473:pathology / Q000628:therapy; D005260:Female; D006046:Gold / Q000737:chemistry*; D056945:Hep G2 Cells; D006801:Humans; D007259:Infrared Rays; D061986:MCF-7 Cells; D018396:Mucin-1 / Q000378:metabolism; D043942:Nanotubes / Q000737:chemistry*; D010789:Phototherapy; D012235:Rhodamines / Q000737:chemistry; D012834:Silver / Q000737:chemistry*; D013059:Spectrum Analysis, Raman
chemical_list: D052157:Aptamers, Nucleotide; D018396:Mucin-1; D012235:Rhodamines; C026188:rhodamine 6G; D012834:Silver; D006046:Gold