Beckman 8000 gamma counter

Biodistribution and clearance studies were performed using female wild type C57BL/6 mice (Charles River Laboratory, Wilmington, MA), as previously reported.^{26 (link)} Typically, ⁶⁴Cu-CuNCs or ⁶⁴Cu-CuNCs-FC131 (approximately 740 kBq/100 μL saline (APP pharmaceuticals, Schaumburg, IL)) was injected into mice anesthetized with inhaled isoflurane through tail vein. At 1, 4, 24 and 48 h post injection, mice were euthanatized by cervical dislocation (n = 4 / time point) and organs of interest were collected, weighed, and counted in a Beckman 8000 gamma counter (Beckman, Fullterton, CA). To measure the clearance of the two nanoclusters, a group of mice (n=4) was housed in a metabolism study cage to collect urine and feces at 4, 24, and 48 h post injection. Standards for each nanocluster were prepared and counted with the biodistribution samples together to calculate percentage of the injected dose per gram of tissue (%ID g⁻¹).

The U87MG tumor-bearing mice were anesthetized with isoflurane and were injected with 100 μL 7.4 MBq (200 μCi) ⁶⁴Cu-doped AuNCs intravenously. All PET scans were performed on an Inveon small-animal PET scanner (Siemens, Erlangen, Germany) at indicated time point post injection. The images were collected for 10 min. For each PET scan, 3-dimensional volumes of interest (VOIs) were drawn over the tumor and muscle on decay-corrected whole-body coronal images and analyzed by Inveon Research Workplace (Siemens). At the endpoint of experiment, the mice were sacrificed and interested organs were harvested, weighted and the radioactivity was measured in a Beckman 8000 gamma counter (Beckman, Brea, CA). Standards were prepared and the organ uptake was calculated as percent of injected dose/gram of tissue (%ID/g).

All animal experiments were carried out in compliance with IACUC guidelines of the Washington University. Biodistribution studies were performed using female wild type C57BL/6 mice (Charles River Laboratories, Wilmington, MA). All the mice were anesthetized with inhaled isoflurane and adminstrated with about 370 kBq of ⁶⁴Cu-Cu@CuO_x-ECL1i or ⁶⁴Cu-Cu@CuO_x-ECL1i-Gem in 100 μL saline (APP pharmaceuticals, Schaumburg, IL) via the tail vein. At 1, 4, and 24 h post injection, the mice were re-anesthetized and euthanatized by cervical dislocation (n = 4/time point). Major Organs of interest from mice were harvested and weighed to acquire the weight of the organs. Then the organs were counted in a Beckman 8000 gamma counter (Beckman, Fullterton, CA) to obtain the radioactivity in these organs. The ⁶⁴Cu-Cu@CuO_x-ECL1i or ⁶⁴Cu-Cu@CuO_x-ECL1i-Gem standards were prepared and counted along with the samples to calculate percentage of the injected dose per gram of tissue (%ID/g). A nonlinear regression analysis was used to calculate the mean blood half-lives of the two nanoparticles (Prism, version 7.03, Graphpad).