Investigating histidinylated highly branched poly(lysine) for siRNA delivery

Area of Science:

• Biotechnology
• Gene Therapy
• Materials Science

Background:

• Short interfering RNA (siRNA) offers targeted gene silencing for genetic disorders.
• Current siRNA therapies often use lipid-based formulations with limited tunable properties.
• Non-viral vectors provide an alternative delivery system for siRNA therapeutics.

Purpose of the Study:

• To investigate the impact of molar mass and histidinylation on poly(lysine) based non-viral vectors for siRNA delivery.
• To optimize vector properties for enhanced stability, efficacy, and tissue selectivity.
• To evaluate the transfection efficiency and cytotoxicity of modified poly(lysine) vectors.

Main Methods:

• Synthesis of poly(lysine) derivatives via aqueous thermal condensation polymerization.
• Formulation of polyplexes with siRNA and characterization of size and N/P ratios.
• In vitro assessment of transfection efficiency, cellular internalisation, and cytotoxicity.

Main Results:

• Higher molar mass poly(lysine) vectors formed smaller polyplexes with enhanced siRNA affinity at lower N/P ratios.
• Increased molar mass correlated with greater transfection efficiency but also showed some cytotoxicity.
• Histidinylation slightly improved biocompatibility but did not significantly enhance gene silencing efficiency.
• Non-histidinylated vectors exhibited greater cellular internalisation, particularly at higher molar masses.

Conclusions:

• Molar mass is a critical parameter for tuning poly(lysine) vector performance in siRNA delivery.
• Higher molar mass poly(lysine) vectors show promise for improved siRNA transfection.
• Histidinylation offers limited benefits for gene silencing efficacy in this poly(lysine) system.
• Further optimization of poly(lysine) vectors is needed to balance efficacy, safety, and cellular uptake.