Preparation and Formulation Screening of Hydrogels
The specific preparation process for the hydrogels is as follows: Accurately weigh 7 g of AAm, 6 mg of MBAA, 0.1 g of LAP, and 0.1 g of CMC-Na, and place them in a beaker. Add 10 g of ultrapure water and stir to mix uniformly. Subsequently, subject the precursor solution to ultrasonic treatment at room temperature for 5-10 minutes to remove bubbles. Finally, expose the precursor solution to a 405 nm light source (intensity: 1.22 mW/cm²) from a distance of 10 cm for 1 minute to induce photopolymerization crosslinking, resulting in the solidification of the hydrogel.
To systematically investigate the relationship between hydrogel properties and crosslinking degree (expressed as the molar ratio of MBAA to AAm, C(×10^-4)), this study prepared hydrogels with different monomer and crosslinker ratios, as detailed in Table 3. Additionally, to examine the changes in hydrogel properties after loading with radioactive isotopes, stable isotopic salts were used as substitutes for the target radioactive isotopes to characterize the materials. Specifically, Na2HPO4, YCl3, SrCl2, and NaI were added to the precursor solution, each at three concentration gradients: 0.1 mg/mL, 0.5 mg/mL, and 1.0 mg/mL. For ease of description, the resulting samples were sequentially named as follows: P-0.1, P-0.5, P-1; Y-0.1, Y-0.5, Y-1; Sr-0.1, Sr-0.5, Sr-1; and I-0.1, I-0.5, I-1.