(232h) Nanomagnetic Illuminators for In Vivo Optical Imaging of Osteoarthritic Knee Joints
AIChE Annual Meeting
Monday, October 29, 2018 - 4:06pm to 4:24pm
Magnetic nanoparticles synthesized by a high temperature synthesis method under aerobic conditions, block copolymer PEG5kDa_PDLLA6kDa, and lipophilic tracer 1,1'-Dioctadecyl-3,3,3',3'-tetramethylindotricarbocyanine iodide (DiR) were dissolved in the water miscible solvent THF. Rapid mixing of the solutes against water (anti-solvent) using a confined impingement jet mixer under high local supersaturation condition resulted in kinetically frozen structures of about 200 nm. The magnetic composite nanocarriers were purified via magnetic separation and dye encapsulation was confirmed using absorbance measurements and an in vivo imaging system.
Toxicity of the DiR loaded magnetic nanocarrier on fibroblast-like synoviocytes was tested using an MTS assay, a colorimetric assay used to analyse cell metabolism. Greater than 80% of the synoviocytes were found viable after 24 hours of particle exposure in the concentration range of 0.1 to 0.8 mg iron oxide/mL, suggesting negligible toxic effects of the nanocarrier under these conditions.
Biodistribution and particle retention studies were performed on 15-month old Lewis rats with healthy and OA induced knees. 60 ug of DiR loaded magnetic composite nanocarrier was injected and distribution of the nanomagnetic illuminator was tracked for 14 days. Further, the retention of the particles in organs of euthanized rats was visualized by IVIS imaging and quantified via EPR. IVIS images of the organs analyzed for radiant efficiency suggested that particles were predominantly retained in the knee joint and cleared faster in a healthy joint as compared to an osteoarthrtic knee. Based on the EPR measurements on the lyophilized organs, we found that ~60 % of the injected iron oxide nanoparticles remained in the joint space. Our studies involving both visualization and quantification of DiR loaded magnetic particle indicate that this carrier can be explored as a safe option to better understand transport of nanoparticles in tissues of joint space and also to deliver hydrophobic drugs for treatment.