Synthesis of low-molecular weight protein (LMWP) lysozyme–curcumin conjugates for kidney drug targeting

The low-molecular weight protein (LMWP) lysozyme is a suitable drug carrier for renal drug targeting. Presented herein is a lysozyme–curcumin renal drug delivery system that possesses the potential to achieve a highly effective yet less toxic therapy. Briefly, the approach involves synthesis of the lysozyme–drug (curcumin) conjugates by coupling the drug to the activated functional groups on lysozyme via hydrolyzable ester linkages. The successful synthesis of LMWP lysozyme–curcumin (LZMC) conjugates was determined by Fourier transform infrared spectroscopy and 1H NMR. The cellular uptake of LZMC conjugates was tested against proximal tubular (HK-2) cells. Compared to free curcumin, the LZMC conjugates exhibited high-cellular uptake efficiency in HK-2 cells. Fluorescence image of mouse kidneys at different time points after free curcumin and LZMC conjugates tail vein injection shows that the kidney of mice injected with LZMC conjugates showed the strongest fluorescence signals, and the specific signals last for at least 26 h.