WNT16 and neoplasm: Utilizing a size-switching strategy controlled by MMP-2, which is present in high concentrations in the tumor microenvironment, the team was able to demonstrate enhanced accumulation of GA-loaded large particles (~88.0 ± 1.1 nm) around blood vessels to suppress Wnt16 expression in CAFs and penetration of gemcitabine conjugated small particles (~28.7 ± 4.1 nm) to deep tumor locations.