Figure 2 AFM images and size distribution. (a) (c) MMT. (b) (d) SbQ-MMT. (c) SD = 20.2; (d) SD = 45. Figure 3 SEM images. (a) MMT. (b) SbQ-MMT. More detailed evidences are shown in Figure 4A. The pristine MMT showed a typical XRD pattern with the basal spacing of 1.24 nm and intercalation of SbQ led to a significant increase in interlayer spacing and a decrease in 2θ. The increased basal Sirolimus price spacing indicated that SbQ had been effectively intercalated into the interlayers of MMT. It could also be seen from the TEM image

(inset) that the MMT was comprised of many parallel silicate layers with about 1.5 to 2 nm interlayer spacing. The interlayer spacing was much larger than the original 1.24 nm of MMT, which gave direct evidence that the SbQ Wnt inhibitor molecules had been intercalated into MMT. From the TGA curves (Figure 4B), the amount of SbQ in the MMT interlayers was about 7.57% (35.71 meq/100 g) [12], which is less than the cation exchange capacity of the sodium MMT. Figure 4 XRD patterns and TEM image and TGA curves. (A) XRD patterns and TEM image: (a) MMT,

(b) SbQ-MMT, and TEM (inset) of SbQ-MMT. (B) TGA curves. Structural analysis Figure 5 shows the FTIR spectra of MMT, SbQ, and cross-linked SbQ-MMT. The peaks exhibited at 3,435, 1,639, and 1,163 to 500 cm−1 were − OH stretching, −OH bending, and oxide bands of metals like Si, Al, and Mg. The shoulders and broadness of the structural − OH band were mainly due to contributions of several structural − OH groups, occurring in the MMT. The overlaid absorption

peak at 1,640 cm−1 was attributed to − OH bending mode of adsorbed water. Peaks at Interleukin-2 receptor 935, 850, and 825 cm−1 could be attributed to AlAlOH, AlFeOH, and AlMgOH bending vibrations, respectively [18]. In the FTIR spectrum of cross-linked SbQ-MMT, characteristic bands belonging to MMT and SbQ appeared, indicating that the cross-linked SbQ had interacted with MMT. The band which appeared at 1,650 cm−1 indicated the aldehydic (−CHO) group of SbQ which could interact with the − NH2 groups present in protein for drug delivery. Figure 5 FTIR spectra of pristine MMT, SbQ, and cross-linked SbQ-MMT. UV-vis spectroscopy was utilized to trace the photo-cross-linking process of SbQ-MMT solution (Figure 6). When the solution was exposed to UV light, the absorbance intensity at around 340 nm decreased continuously with increased irradiation time, which indicated the dimerization of SbQ moieties [5]. SbQ moieties were completely cross-linked after 120 min. Figure 6 UV-vis spectra of the photo-cross-linking process of SbQ-MMT solution as a function of irradiation time. Conclusions In summary, SbQ was successfully intercalated into MMT via cationic exchange interactions and were irradiated under UV light to get the cross-linked SbQ-MMT.