Carbon Dots-AS1411 Aptamer Nanoconjugate for Ultrasensitive Spectrofluorometric Detection of Cancer Cells

Abstract In the present study, a sensitive and selective signal-on method for aptamer based spectrofluorometric detection of cancer cells is introduced. AS1411, a nucleolin aptamer, is wrapped around water-soluble carbon dots and used as a probe for the detection of several types of cancer cells. Nucleolin, is overexpressed on the surface of cancer cells. Mouse breast 4T1, human breast MCF7, and human cervical HeLa cancer cells were selected as target cells, while human foreskin fibroblast cells HFFF-PI6 served as control cells. For the sensitive and selective spectrofluorimetric detection of target cancer cells in the presence of control cells, the cells were incubated in carbon dots-aptamer solutions, the cell suspensions were subsequently centrifuged and the fluorescence intensities were measured as an analytical signal. The specific targeting of cancer cells by AS1411 aptamers causes the release of carbon dots and enhances the fluorescence intensity. A calibration curve with a dynamic range between 10–4500 4T1 cells and detectability of roughly 7 cells was obtained. In addition, no significant change in the signal was detected by modifying the amount of human foreskin fibroblast control cells. Our results demonstrate similar responses to human MCF7 breast and cervical HeLa cancer cells

Preparation and Characterization of Spion-CDs as a Multifunctional Fluorescence/Magnetic Resonance Nanoparticle

A multifunctional nanoparticle, Super Paramagnetic Iron Oxide Nanoparticle-Carbon Dots (SPION-CDs), for fluorescence and magnetic resonance imaging is introduced. This nanoparticle possesses the magnetic properties of super-paramagnetic iron oxide (SPION) core as well as the fluorescence characteristics of carbon dots (CDs) coated in mesoporous structure. The SPION-CDs were synthesized using a high temperature facile single-pot hydrothermal method. The products were characterized by transmission electron microscopy (TEM), dynamic light scattering (DLS), X-ray diffraction (XRD), UV/vis absorption, vibrating sample magnetometer (VSM). The cytotoxic effect of SPION-CDs on OVCAR-3 cells was also evaluated. The synthesized nanoparticle possesses optimal size, low toxicity and excellent magnetic properties, including super-paramagnetic behavior (Ms = 42 emu g−1). Moreover, in the viewpoint of optical properties, the quantum yield of ~2.4% was obtained and the nanoparticle shows good fluorescence stability for cell-labeling studies. This multifunctional nanoparticle with appropriate characterization is a promising candidate for multimodal fluorescence/magnetic resonance imaging platform

Green and Facile Synthesis of Highly Photoluminescent Multicolor Carbon Nanocrystals for Cancer Therapy and Imaging

Carbon dots (CDs), as a new generation of fluorescent nanoparticles, have been greatly considered for different biomedical applications. In the present study, a one-pot hydrothermal method was developed for the synthesis of a series of carbon dots (CDs) for cancer imaging and therapy. Taxane diterpenoids were utilized as the carbon source, different diamines were used as the nitrogen source, and folic acid was used as a targeting agent. High-quality photostable and multicolor (blue and green) carbon nanocrystals with a hexagonal shape, a narrow size distribution of less than 20 nm, and high fluorescence quantum yield of up to 50.4% were obtained from taxanes in combination with m-phenylenediamine and folic acid to give the best results. The nanoparticles displayed a potent anticancer activity with IC50 values of 31.3 ± 2.7 and 34.1 ± 1.1 μg mL–1 for the human MCF-7 and HeLa cancer cell lines, respectively, and IC50 value of 120.5 ± 3.8 μg mL–1 on the normal human fibroblast cells. The flow cytometry studies determined apoptosis-mediated cell death as the main anticancer mechanism of CDs, and the molecular studies revealed the induction of both extrinsic and intrinsic apoptosis pathways. The overall results indicated the great potential of synthesized CDs for the simultaneous cancer imaging and therapy