eng Oriental Scientific Publishing Company Biosciences Biotechnology Research Asia 0973-1245 2016-06-16 12 Spl.Edn.1 131 140 10.13005/bbra/1615 12658 article Yadollahpour Ali 1 Rezaee Zohre 1 Jalilifar Mostafa 1 Rashidi Samaneh 1 Department of Medical Physics, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Golestan Blvd., Ahvaz, Iran. Molecular imaging (MI) is visualization and characterization of biological processes at the sub-cellular level. Early diagnosis and monitoring of treatment procedure are main advantages of this approach. Molecular probe with high affinity is one of the important requirements of MI. Within the extensive group of nanoparticles, upconversion nanoparticles that play a prominent role in optical MI cab be used as an MI probe. Upconversion phosphors are ceramic materials in which rare earth atoms are embedded in a crystalline matrix structure. The materials absorb light in the near infrared region and emit in the visible region via several mechanisms. This agent can be used for optical imaging, gene or drug delivery and photodynamic therapy. The present study reviews the recent development in synthesis and modulating the characteristics of upconversion nanoparticles and their applications in MI. Furthermore, recent research approaches and future opportunities regarding the development of these nanoparticles are discussed. https://www.biotech-asia.org/vol12_nospl_edn1/applications-of-upconversion-nanoparticles-in-molecular-imaging-a-review-of-recent-advances-and-future-opportunities/ Molecular Imaging; Fluorescent Nanoparticles; Upconversion Nanoparticles; Contrast Agents