Figure 2.

Uniform attachment and characterization of a murine Class II MHC-specific targeting nanobody, VHH7, on GO nanosheets. a, Overview of sortase-mediated site-specific ligation of VHH7 onto GO nanosheets. VHH7 was C-terminally modified via a sortase-mediated ligation to install a TAMRA fluorophore and an azide. The GO nanosheet was functionalized with a DBCO handle for a “click” reaction with the azide-modified VHH7. b, AFM images of GO nanosheets and GO nanosheets with VHH7 immobilized on silicon substrates. The height difference between GO nanosheets with or without VHH7 immobilization was ~20–80 nm. The topography of the slide observed under the AFM is characteristic of protein bound to GO.[6] c, Whole blood analysis from Class II MHC-eGFP knock-in mice. A small volume of blood (30 μL) was loaded into the assembled chamber and incubated at 37°C for 10 min. The chamber was then disassembled and the cell-bearing substrate slide was gently washed 3x with PBS. After washing, cells were analyzed by fluorescence microscopy and quantitative image analysis.