In vivo biodistribution studies and ex vivo lymph node imaging using heavy metal-free quantum dots

Abstract

Quantum dots (QDs) are attractive photoluminescence probes for biomedical imaging due to their unique photophysical properties. However, the potential toxicity of QDs has remained a major obstacle to their clinical use because they commonly incorporate the toxic heavy metal cadmium within the core of the QDs. In this work, we have evaluated a novel type of heavy metal-free/cadmium-free and biocompatible QD nanoparticles (bio CFQD® nanoparticles) with a good photoluminescence quantum yield. Sentinel lymph node mapping is an increasingly important treatment option in the management of breast cancer. We have demonstrated their potential for lymph node mapping by ex vivo imaging of regional lymph nodes after subcutaneous injection in the paw of rats. Using photoluminescence imaging and chemical extraction measurements based on elemental analysis by inductively coupled plasma mass spectroscopy, the quantum dots are shown to accumulate quickly and selectively in the axillary and thoracic regional lymph nodes. In addition, lifetime imaging microscopy of the QD photoluminescence indicates minimal perturbation to their photoluminescence properties in biological systems.

Labeling and in vivo visualization of transplanted adipose tissue-derived stem cells with safe cadmium-free aqueous ZnS coating of ZnS-AgInS2 nanoparticles

“…Thus, the development of novel QDs with extremely low cytotoxicity (especially Cd-free alternatives) is necessary for further advancement of QD technology15161718. There have been some reports about the cadmium-free QDs such as carbon or CuInS 2 /ZnS QDs192021. We previously reported the facile synthesis of ZnS-AgInS 2 (ZAIS) as a cadmium-free QD, and confirmed that ZAIS was useful as a color-adjustable fluorophore mainly for solar cells2223.…”

How can nanotechnology help the fight against breast cancer?

“…4A). 58,64,67,[73][74][75][120][121][122][123][124][125][126][127][128][129][130][131][132][133][134] Both of them have shown to be excellent imaging tools for many in vitro studies on murine and human cancer cells.…”

“…Thanks to their fluorescence properties upon excitation, their high brightness and photostability, they represent unique nanomaterials ideal for in vivo imaging in animal cancer models, as shown in the measurement of the receptor expression level of type I insulin-like growth factor receptor (IGFIR) involved in BC proliferation and metastasis. 122 QDs have been coated with polymer to enhance biocompatibility, 64,89,92,95,101,114,120,133,172 or conjugated with antibodies to detect overexpressed receptors. 85, 88, 90, 91, 98, 99, 107-110, 116, 122, 135 The fourth position is held by gold nanoparticles, used for tumor detection, diagnosis, and cancer therapy, due to the possibility of an easy surface modification.…”

“…In vitro / In vivo (CT26, 4T1, LLC, B16F10 cells) [118] Quantum Dots Metal-free/cadmiumfree (bio CFQD®) CLSM In vitro / Ex vivo (MCF-7 cells) [133] Polyamidoaminebased Silica Nanoparticles Antibody (anti-HER2) NIR…”

Quantum dots in imaging, drug delivery and sensor applications

“…Moreover, the lack of any Class A elements (Cd, Hg and Pb) in their structure makes suitable candidates for future biomedical applications. 13 Another interesting approach for biomedical imaging applications was reported by Yu et al, which developed gadolinium-doped carbon dots for fluorescence/magnetic resonance imaging (MRI) imaging. A one-pot hydrothermal method was employed in order to obtain bio-imaging nanoprobes (~5.5 nm in size, nearly spherical) from citric acid, with high spatial resolution for MRI and enhanced fluorescence compared to that of carbon dots alone.…”