Additional file 1 of Attention-deficit hyperactivity disorder in children is related to maternal screen time during early childhood in Taiwan: a national prospective cohort study

Supplementary Material

Facile Synthesis of Radial-Like Macroporous Superparamagnetic Chitosan Spheres with In-Situ Co-Precipitation and Gelation of Ferro-Gels

<div><p>Macroporous chitosan spheres encapsulating superparamagnetic iron oxide nanoparticles were synthesized by a facile and effective one-step fabrication process. Ferro-gels containing ferrous cations, ferric cations and chitosan were dropped into a sodium hydroxide solution through a syringe pump. In addition, a sodium hydroxide solution was employed for both gelation (chitosan) and co-precipitation (ferrous cations and ferric cations) of the ferro-gels. The results showed that the in-situ co-precipitation of ferro-ions gave rise to a radial morphology with non-spheroid macro pores (large cavities) inside the chitosan spheres. The particle size of iron oxide can be adjusted from 2.5 nm to 5.4 nm by tuning the concentration of the sodium hydroxide solution. Using Fourier Transform Infrared Spectroscopy and X-ray diffraction spectra, the synthesized nanoparticles were illustrated as Fe₃O₄ nanoparticles. In addition, the prepared macroporous chitosan spheres presented a super-paramagnetic behaviour at room temperature with a saturation magnetization value as high as ca. 18 emu/g. The cytotoxicity was estimated using cell viability by incubating doses (0∼1000 µg/mL) of the macroporous chitosan spheres. The result showed good viability (above 80%) with alginate chitosan particles below 1000 µg/mL, indicating that macroporous chitosan spheres were potentially useful for biomedical applications in the future.</p> </div

Morphologies of the synthesyzed chitosan spheres.

<p>(a) An optical image of the iron oxide nanoparticles loaded chitosan spheres. (b) SEM images of chitosan spheres without (left) and with (right) iron oxide nanoparticles. (c) and (d) show the cross-section images of chitosan spheres (without iron oxide nanoparticles). Inset in (c) shows the sliced hemispheres of chitosan sphere. Inset in (d) shows details of the internal structure. (e) and (f) show the cross-section images of iron oxide nanoparticles loaded chitosan spheres.</p

Characterization of the iron oxide-chitosan composite spheres.

<p>(a) FTIR spectra of chitosan spheres (gray line) and iron oxide nanoparticle-loaded chitosan spheres (black line). (b) X-ray diffraction pattern from iron oxides nanoparticle-loaded chitosan spheres prepared from the NaOH solutions with various concentrations.</p

Schematic of the formation process of macroporous chitosan spheres.

<p>Schematic of the formation process of macroporous chitosan spheres.</p