Spect discovery 670

SPECT/CT imaging was performed using Inliview‐3000B (Novel Medical, China) with ^99mTcO₄ at dose of 0.5 mCi/20 g mouse body weight 30 min post intraperitoneal injection. Mice were injected via tail vein with ¹³¹I 0.5 mCi/20 g body weight and imaged 30 min later by SPECT Discovery 670 (GENERAL ELECTRIC, USA). Each group included both male and female at age of 5w. The resulting image data were normalised to the administered activity of the percentage of the injected dose per gram of mice (%ID/g) according to previous protocols.
²⁹ And the %ID/g was determined with same 3D volumes of interest in different mice.

To prepare ¹³¹I‐labelled nanoparticles (NPs), MSNs‐NH₂ and BSA were mixed with appropriate concentration of 1‐ethyl‐3‐(3‐dimethylaminopropyl) carbodiimide hydrochloride and N‐hydroxysuccinimide for 3 h. Then, miR‐31 antagomir was added to the MSNs‐BSA NPs to form the MSNs‐BSA‐Anta NPs. The ¹³¹I was then labelled with chloramine T method to form the MSNs‐BSA‐Anta‐¹³¹I NPs.
³⁰ NPs morphology was detected by transmission electron microscope (TEM) (HT7700; HITACHI). Particle‐size distribution and zeta (ζ)‐potential were analysed on a Malvern Nano‐ZS90 instrument (Malvern, UK). In the therapeutic model, mPTC mice including both male and female at age of 3w were injected with NPs at a dose of 50 mg/kg body weight and NPs labelled with ¹³¹I at a dose of 0.6 mCi/20 g body weight through tail vein twice a week, n = 8 per group. After five times of treatment, only n = 6 tumours each group were harvested due to animal deaths. SPECT/CT imaging was performed at different times with SPECT Discovery 670 (GENERAL ELECTRIC). And the tumours were then collected for further analyses.