Synthesis of 99mTc(CO)3-deoxyuridine derivatives as potential HSV1-tk gene expression imaging agents.

In this study, we synthesized (99m)Tc(CO)(3)-2'-aminomethylpyridyl-2'-deoxyuridine ((99m)Tc(CO)(3)-AMPDU) and (99m)Tc(CO)(3)-aminoethylpyridyl-2'-deoxyuridine ((99m)Tc(CO)(3)-AEPDU) as potential agents for imaging the expression of the non-invasive herpes simplex virus type-1 thymidine kinase. AMPDU and AEPDU were synthesized from uridine in five chemical steps and then labeled with [(99m)Tc(CO)(3)(H(2)O)(3)](+) (370MBq/0.5 mL) at 100 degrees C for 10 min. Under optimal conditions (0.5 and 1.0mg for AMPDU and AEPDU and heating for 10 min), the labeling efficiency was 95.3+/-2.8% for AMPDU and 94.2+/-5.1% for AEPDU. To validate the chemical structure of (99m)Tc(CO)(3)-labeled compounds, we also synthesized ReBr(CO)(3)-AMPDU and ReBr(CO)(3)-AEPDU by reacting [Et(4)N][ReBr(3)(CO)(3)] and AMPDU or AEPDU in methanol at 25 degrees C for 6h. (99m)Tc(CO)(3)-AMPDU and (99m)Tc(CO)(3)-AEPDU had the same retention time on HPLC analysis as ReBr(CO)(3)-AMPDU and ReBr(CO)(3)-AEPDU. (99m)Tc(CO)(3)-AMPDU and (99m)Tc(CO)(3)-AEPDU had high radiochemical stabilities of 98.1+/-1.5% and 98.0+/-1.7% for 6h, respectively.

LiI-Doped Sulfide Solid Electrolyte: Enabling a High-Capacity Slurry-Cast Electrode by Low-Temperature Post-Sintering for Practical All-Solid-State Lithium Batteries.

All-solid-state lithium batteries (ASSLBs) based on sulfide solid electrolytes (SEs) have received great attention because of the high ionic conductivity of the SEs, intrinsic thermal safety, and higher energy density achievable with a Li metal anode. However, studies on practical slurry-cast composite electrodes show an extremely limited battery performance than the binder-free pelletized electrodes because of the poor interfacial robustness between the active materials and SEs by the presence of a polymeric binder. Here, we employ a low-temperature post-sintering process for the slurry-cast composite electrodes in order to overcome the binder-induced detrimental effects on the electrochemical performance. The LiI-doped Li3PS4 SEs are chosen because the addition of iodine not only improves the Li-ion conductivity and Li metal compatibility but also lowers the glass-transition and crystallization temperatures. Low-temperature post-sintering of composite cathodes consisting of a LiNi0.6Co0.2Mn0.2O2-active material, LiI-doped Li3PS4 SE, polymeric binder, and conducting agent shows a significantly improved electrochemical performance as compared to a conventional slurry-cast electrode containing pre-annealed SEs. Detailed analyses by electrochemical impedance spectroscopy and galvanostatic intermittent titration technique confirm that post-sintering effectively reduces the interfacial resistance and enhances the chemomechanical robustness at solid-solid interfaces, which enables the development of practical slurry-cast ASSLBs with sulfide SEs.