Scheme 1.

Schematic representation of KLPPR liponanoparticles for kidney-targeted drug delivery. (A) KLPPR liponanoparticles consisted of a RH-loaded PCL-PEI nanoparticular core and a KTP-modified lipid layer were created, based on the principle of electrostatic interaction between the electropositive core and electronegative lipid layer. (B) The concept of the two-step nanoparticular cascade including size control and enhancement of renal cellular uptake. Maintaining the size in the range of 30 ~ 80 nm allowed KLPPR enter kidney by passing through the glomerular filtration membrane (1); KTP decoration promoted the renal cellular uptake and internalization via membrane fusion and improved the kidney retention of KLPPR (2).