Highly fluorescent and superparamagnetic nanosystem for biomedical applications

Abstract

This work reports on highly fluorescent and superparamagnetic bimodal nanoparticles (BNPs) obtained by a simple and efficient method as probes for fluorescence analysis and/or contrast agents for MRI. These promising BNPs with small dimensions (ca. 17 nm) consist of superparamagnetic iron oxide nanoparticles (SPIONs) covalently bound with CdTe quantum dots (ca. 3 nm). The chemical structure of the magnetic part of BNPs is predominantly magnetite, with minor goethite and maghemite contributions, as shown by Mössbauer spectroscopy, which is compatible with the x-ray diffraction data. Their size evaluation by different techniques showed that the SPION derivatization process, in order to produce the BNPs, does not lead to a large size increase. The BNPs saturation magnetization, when corrected for the organic content of the sample, is ca. 68 emu g, which is only slightly reduced relative to the bare nanoparticles. This indicates that the SPION surface functionalization does not change considerably the magnetic properties. The BNP aqueous suspensions presented stability, high fluorescence, high relaxivity ratio (r /r equal to 25) and labeled efficiently HeLa cells as can be seen by fluorescence analysis. These BNP properties point to their applications as fluorescent probes as well as negative T -weighted MRI contrast agents. Moreover, their potential magnetic response could also be used for fast bioseparation applications.

Assessment of Charged AuNPs: From Synthesis to Innate Immune Recognition

“…In the dawn of a new era of biomedical advancements, nanotechnology has paved the way to manipulate and tailor matters at the nanometer scale, which permits the engineering of a wide array of nanomaterials [1,2]. Engineered nanoparticles (NPs), particularly gold nanoparticles (AuNPs), are one of the most commonly studied substances due to their widespread use in biomedical applications, cosmetics, and cancer treatment [3][4][5][6][7]. AuNPs exhibit attractive physicochemical and optical properties, fast biodistribution, and dosedependent cytotoxicity [8][9][10][11].…”

Gd- and Eu-Loaded Iron Oxide@Silica Core–Shell Nanocomposites as Trimodal Contrast Agents for Magnetic Resonance Imaging and Optical Imaging

“…30 The M S value of FS is smaller than the value of F, presumably because of induced spin canting at the core/silica coating interface. 31 The slight further reduction of M S for FSb-Gd and FSb-EuGd indicates that the diamagnetic contribution from the inserted complexes fully counterbalances the Gd 3+ and Eu 3+ paramagnetic contribution. This is confirmed by the absence of a paramagnetic contribution to their M(H) curves, which would be visible at very low and very high magnetic fields.…”

“…The M S value obtained for bare F at 298 K is lower than that of bulk maghemite (78 emu g –1 ) . The M S value of FS is smaller than the value of F, presumably because of induced spin canting at the core/silica coating interface . The slight further reduction of M S for FSb-Gd and FSb-EuGd indicates that the diamagnetic contribution from the inserted complexes fully counterbalances the Gd 3+ and Eu 3+ paramagnetic contribution.…”

Gold Nanoparticles Conjugated with Dendrigraft Poly-L-lysine and Folate-Targeted Poly(ethylene glycol) for siRNA Delivery to Prostate cancer

“…Due to enzymatic degradation, renal clearance, and electrostatic repulsion with the negatively charged phospholipidic membrane, unprotected siRNA exhibits a short plasma half-life 9 , 10 . Therefore, the complexation of siRNA with nanoparticles (NPs) has been recently exploited to improve siRNA-based therapeutic applications in cancer treatment 9 , 11 . In fact, it has been demonstrated that NPs-siRNA cargos can shield naked siRNA from degradation and can be further modified with a ligand to specifically recognize a tumor cell with targeted siRNA delivery 12 , 13 .…”