Synthesis and characterization of functional chitosan-based microspheres as biodegradable yttrium-90 delivery system...

Transarterial radioembolization (TARE) using yttrium-90 (⁹⁰Y)-labeled glass and resin microspheres is an emerging therapeutic technique for hepatocellular carcinoma (HCC). However, the non-biodegradability and rapid settlement of current commercial microspheres might hinder their even distribution and repetitive administration thus causing unsatisfactory therapeutic effects. In this context, novel functional chitosan-based microspheres (CPIs) that can efficiently label Y as a favorable TARE material were developed for the first time by successive grafting poly (glycidyl methacrylate) (PGMA) and iminodiacetic acid (IDA) onto chitosan microspheres (CMs). The results confirmed that the CPIs had desirable spherical shapes with average diameters of around 20.9 microm, an ideal settlement rate within 5 min, and considerable biodegradability at 10th weeks. It reached Y adsorption equilibrium within 30 min and maintained the maximum adsorption capacity up to 14.95 mg g^-1 at pH 6.0 following pseudo-second-order kinetic and Langmuir models. Additionally, Y-labeled CPIs were rather stable in vitro, for which Y would firmly interact with the sodium carboxylate group and tertiary amine nitrogen atoms on IDA, and its leakage when shaken in phosphate-buffered saline for 24 h was barely detected. Altogether, these properties of the as-developed CPIs hold great potential as promising radioembolization microspheres for TARE therapy against liver cancer.