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Accueil > Séminaires > Archive des séminaires d’Utinam > 2015

Timothy Tan

Photo-Driven Upconversion Nanodevices as Theranostics : Bioimaging and Near-infrared Mediated Cancer Cell Killing

jeudi 29 janvier 2015, 14h30

salle 018N, bâtiment N

Attention : séminaire annulé

Timothy TAN, School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapour

Résumé :
This talk will focus on the various strategies to design and tailor upconversion nanostructures
for biomedical application. Using lanthanide elements, our lab has synthesized nanomaterials
of different morphologies and multiple functionalities, and demonstrated their potential
applications in simultaneous upconversion optical imaging (near-infrared (NIR) activated), X-ray Computed Tomography (CT) (Fig 1a) and magnetic resonance imaging (MRI) (Fig 1b). By encasing the lanthanide-based nanocrystals with a nitrogen-doped TiO2 photosensitizer and functionalizing with a cancer-targeting antibody (Fig 2), our lab has innovated a novel
photo-driven nanodevice which was conferred with targeted anti-tumor property, activated by NIR which is non-phototoxic and can penetrate deeper into tissues.

We are currently working with clinicians in Singapore National Skin Centre to demonstrate upconverted photodynamic therapy for squamous-cell carcinomas (SCC), and envision that the current lanthanide-based nanodevices are promising as a new type of theranostics for skin cancer.

Figure 1.
Figure 1. (a) CT images and (b) the measured CT values (Hounsfild units, HU) of the citric acid modified
NaYbF4:Tm (10%), Iohexol and NaYF4:Yb/Tm (20%/1%) with different concentrations. ( Chem. Mater. , 2014,
26 (18), pp 5183–5186). (c) T2-weighted image using spin echo sequence and (d) T1-weighted MR image using
spin echo sequence of NaDyF4:Yb3+/ NaGdF4:Yb3+,Er3+ NCs fixed 0.8 % agarose, injected subcutaneously in
mouse model. (i) represents control, 0.8% agarose. (ii) represents NC fixed in 0.8% agarose. The experimental
parameters for T1- and T2-weighted images are TR/TE/NEX = 400/8.9/16 and TR/TE/NEX =1500/41/16,
respectively.( Nanoscale , 2014, DOI : 10.1039/C4NR01717J)

Fig 2.
Fig 2. Schematic illustration of lanthanide-N-TiO2 nanocomposite activation by a 980 nm NIR laser for cancer
cells targeting and ablation ( Adv Healthcare Materials , 2012 1 4 p470)

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