Small animal live imaging system

Mice were administrated with 500 ul ERFP-labeled genetic engineering E.coli solution (10⁹ CFU/ml) in PBS and were euthanized after 12 h, and liver, spleen and intestine were collected. Bruker Small Animal Live Imaging System was used to assess PE signal in these tissues, with radiant efficiency assessed via Bruker MI SE software.

The fluorescently labeled dye with an excitation wavelength of 550 nm (EFL-DYE-UF-ENE-R) was dissolved in LAP at 5 mg/ml to prepare fluorescent hydrogels. All samples were divided into SilMA, MSN/SilMA, Ag@MSN/SilMA and Ag@MSN-BMP-2/SilMA groups. The hydrogels were made into cylinders with a diameter of 1 cm and a height of 5 mm using a mold. Mice were anesthetized, then the backs of the mice were shaved and sterilized. The samples were implanted into the backs of the mice (n = 40, 10 mice per group). Photographs were taken immediately after the operation (day 0) and at weeks 1, 4 and 8 using a subcutaneously small-animal live imaging system (Bruker) to observe and record hydrogel degradation in different groups.
All samples in SilMA, MSN/SilMA, Ag@MSN/SilMA and Ag@MSN-BMP-2/SilMA groups were crosslinked to assess the biocompatibility of the composite hydrogels by UV light in vivo, and subcutaneously implanted into the back of rats (n = 40, 10 rats per group). The rats were anesthetized at 1, 4 and 8 weeks after implantation, and each implanted hydrogel scaffold was removed and weighed to plot the degradation curve. Skin tissue fixed, embedded in paraffin, and sectioned. Hematoxylin–eosin (H&E) staining and CD68 (DF7518, Affinity) immunofluorescence were subsequently performed to assess the in vivo biocompatibility of the hydrogels.