Lysine-based dendrimer with double arginine residues

Area of Science:

• Nanotechnology
• Polymer Chemistry
• Biomaterials Science

Background:

• Lysine dendrimers are promising nanocarriers for drug and gene delivery due to their favorable properties.
• Modification with arginine (Arg) residues is a strategy to enhance gene delivery efficiency.

Purpose of the Study:

• To synthesize and characterize a novel second-generation poly-l-lysine dendrimer incorporating arginine residues (Lys-2Arg).
• To investigate the physicochemical properties and structural changes upon arginine incorporation.

Main Methods:

• Synthesis of the Lys-2Arg dendrimer.
• Structural confirmation using 1D and 2D ¹H and ¹³C NMR spectroscopy.
• Analysis of molecular dynamics using T_1H relaxation measurements.

Main Results:

• The structure of the Lys-2Arg dendrimer was successfully confirmed.
• Arginine incorporation led to a significant decrease in the mobility of methylene groups in both side chains and the main chain.
• This reduction in mobility was attributed to guanidine-guanidine pairing in aqueous solution, causing inter-branch entanglements.

Conclusions:

• The synthesized Lys-2Arg dendrimer exhibits altered physicochemical properties compared to lysine-only dendrimers.
• Guanidine-guanidine pairing is proposed as a mechanism for reduced mobility and potential for enhanced gene delivery applications.