Type of presentation: Oral

LS-1-O-1407 Imaging of oxygenation in 3D tissue models by means of cell-penetrating phosphorescent nanosensors

Papkovsky D. B.1, Dmitriev R. I.1
1University College Cork, Cork, Ireland
d.papkovsky@ucc.ie

Recently we have developed several cell-penetrating phosphorescent probes (small molecule and nanoparticle based structures [1,2]) which allow real-time, high-resolution imaging of O2 concentration in respiring cells and tissues and detailed metabolic and physiological studies with 3D tissue models. The probes can be used on standard imaging platforms and in different detection modalities, with preference to confocal microsecond FLIM/PLIM (i.e. phosphorescence lifetime based O2 sensing) or ratiometric intensity imaging, under one and two-photon excitation [1]. The utility and performance of these probes and O2 imaging method have been demonstrated with 2D cell cultures, multi-cellular spheroids (neurospheres from primary neurons and cancer cell spheroids), slices of brain and colon tissue and live animals [2-4].

In the talk we will describe different probe structures, their use and O2 sensing principles, mechanisms of cellular uptake, toxicity and safety aspects. This will be illustrated with examples of imaging experiments performed with different cell and tissue models, including multi-parametric and functional imaging of live tissue, effects of hypoxic environment, drug action and metabolic stimulation. These new chemistries and imaging methodologies provide powerful tools for life science and biomedical research with long-ranging applications.

References:

1. Kondrashina AV et al, A phosphorescent nanoparticle based probe for sensing and imaging of (intra)cellular oxygen in multiple detection modalities, Adv Funct Mater, 2012, 22: 4931.

2. Dmitriev RI et al, Imaging of neurosphere oxygenation with phosphorescent probes, Biomaterials, 2013, 34: 9307.

3. Dmitriev RI et al, Small molecule phosphorescent probes for O2 imaging in 3D tissue models, Biomater. Sci., DOI:10.1039/C3BM60272A.

4. Tsytsarev V et al, In vivo imaging of brain metabolic activity using a phosphorescent oxygen-sensitive probe, J. Neurosci Meth., 2013, 216(2): 146-51.

Science Foundation Ireland, Grants 12/RC/2276, 12/TIDA/B2413, and EC FP7 Program, grant FP7-HEALTH-2012-INNOVATION-304842-2.

Fig. 1: Fig. 1. 3D FLIM image of a respiring neurosphere showing heterogeneous distribution of probe lifetime and O2 (left), and phosphorescence decays for ROIs with high (green) and low (orange) O2 concentration (right).