ROS-Response-Induced Zwitterionic Dendrimer for Gene Delivery

Area of Science:

• Biomaterials Science
• Nanotechnology
• Gene Therapy

Background:

• Gene therapy offers high therapeutic potential but faces challenges with intracellular gene release and toxicity.
• Nonviral gene vectors like dendrimers show promise but require improved efficiency and safety.
• Current gene delivery systems struggle to balance high transfection rates with low cytotoxicity.

Purpose of the Study:

• To design and synthesize a novel reactive oxygen species (ROS)-responsive dendrimer for enhanced gene delivery.
• To investigate the charge-transition properties of the dendrimer in response to elevated ROS levels in cancerous cells.
• To evaluate the gene transfection efficiency and cytotoxicity of the novel dendrimer compared to commercial standards.

Main Methods:

• Synthesis of a ROS-responsive dendrimer, poly(amido amine)- N-(4-boronobenzyl)- N, N-diethyl-2-(propionyloxy)ethan-1-aminium (PAMAM-(B-DEAEP)16).
• Characterization of zeta potential changes under varying hydrogen peroxide (H2O2) concentrations using dynamic light scattering.
• Assessment of DNA condensation and release using gel retardation assays and fluorescence-labeled DNA.
• Evaluation of cellular uptake and cytotoxicity compared to poly(ethyleneimine) (PEI).

Main Results:

• PAMAM-(B-DEAEP)16 demonstrated a tunable zeta potential, shifting from positive (+12.3 mV) to negative (-5 mV) in the presence of 80 mM H2O2.
• The dendrimer exhibited a transition to a zwitterionic state, facilitating sustained DNA release within approximately 6 hours.
• Complete cellular uptake was observed within 4 hours, with significantly higher gene transfection efficiency and lower cytotoxicity than commercial PEI.

Conclusions:

• The ROS-responsive dendrimer PAMAM-(B-DEAEP)16 offers a novel strategy for stimuli-triggered gene delivery.
• This approach overcomes the traditional compromise between transfection efficiency and toxicity by adapting charge properties to the cellular microenvironment.
• The study presents a new avenue for designing advanced gene carriers with improved performance and safety for clinical gene therapy applications.