RT Journal Article SR Electronic T1 Evaluation of Upconverting nanoparticles towards heart theranostics JF bioRxiv FD Cold Spring Harbor Laboratory SP 721035 DO 10.1101/721035 A1 Kermorgant Marc A1 Ben Salem Jennifer A1 Santelli Julien A1 Calise Denis A1 Oster Anne-Cécile A1 Lairez Olivier A1 Coudret Christophe A1 Verelst Marc A1 Gales Céline A1 Senard Jean-Michel A1 Beaudry Francis A1 Pavy-Le Traon Anne A1 Roux Clément A1 Mauricot Robert A1 Dina N. Arvanitis YR 2019 UL http://biorxiv.org/content/early/2019/07/31/721035.abstract AB Restricted and controlled drug delivery to the heart remains a challenge giving frequent off-target effects as well as limited retention of drugs in the heart. There is a need to develop and optimize tools to allow for improved design of drug candidates for treatment of heart diseases. Over the last decade, novel drug platforms and nanomaterials were designed to confine bioactive materials to the heart. Yet, the research remains in its infancy, not only in the development of tools but also in the understanding of effects of these materials on cardiac function and tissue integrity. Upconverting nanoparticles are nanomaterials that recently accelerated interest in theranostic nanomedicine technologies. Their unique photophysical properties allow for sensitive in vivo imaging that can be combined with spatio-temporal control for targeted release of encapsulated drugs.Here we synthesized upconverting NaYF4:Yb,Tm nanoparticles and show for the first time their innocuity in the heart, when injected in the myocardium or in the pericardial space in mice. Nanoparticle retention and upconversion in the cardiac region did not alter heart rate variability, nor cardiac function as determined over a 15-day time course ensuing the sole injection. Altogether, our nanoparticles show innocuity primarily in the pericardial region and can be safely used for controlled spatiotemporal drug delivery.Our results support the use of upconverting nanoparticles as potential theranostics tools overcoming some of the key limitations associated with conventional experimental cardiology.