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Preparation and Characterization of Individual and Multi-drug Loaded Physically Entrapped Polymeric Micelles
Published on: August 28, 2015
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Blended Block Polycation Micelles Enhance Antisense Oligonucleotide Delivery
Mckenna G Hanson1, Christian J Grimme2, Nicholas W Kreofsky1
1Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States.
Bioconjugate Chemistry
|July 12, 2023
Summary
Mixing diblock polymers enhances delivery of antisense oligonucleotides (ASOs). Blending morpholino ethyl acrylamide (M) with dimethyl amino ethyl acrylamide (D) significantly increased transfection efficacy, offering a facile method for optimizing genetic medicine delivery systems.
Area of Science:
- Polymer chemistry
- Nanotechnology
- Genetic medicine
Background:
- Antisense oligonucleotides (ASOs) are crucial genetic medicines for downregulating protein production.
- Effective cellular delivery of ASOs requires specialized vehicles, as they cannot enter cells independently.
- Diblock polymers form self-assembled micelles that improve ASO delivery compared to linear variants, but optimization is hindered by synthetic bottlenecks.
Purpose of the Study:
- To develop a high-throughput method for discovering new micelle systems by mixing diblock polymers.
- To accelerate the screening and optimization of polymeric delivery vehicles for nucleic acid-based therapeutics.
- To investigate the impact of polymer blending on micelle formulation and antisense oligonucleotide (ASO) delivery efficiency.
Main Methods:
- Synthesized diblock polymers with varying cationic moieties: amino ethyl acrylamide (A), dimethyl amino ethyl acrylamide (D), and morpholino ethyl acrylamide (M).
- Created homomicelles, mixed micelles (mixing two homomicelles), and blended diblock micelles (blending two diblocks).
- Tested micelle formulations for ASO delivery efficiency and evaluated cellular mechanisms using Bafilomycin-A1 (Baf-A1).
Main Results:
- Mixing or blending M with A did not improve transfection efficiency over A100 homomicelles.
- Mixed micelles of M and D (MixD50+M50) showed significantly increased transfection efficacy compared to D100 homomicelles.
- Blended diblock micelles (BldD20M80) demonstrated a substantial increase in transfection and minimal toxicity, outperforming D100 and MixD20+M80.
- Formulations containing D showed reduced performance with Baf-A1, indicating reliance on the proton sponge effect for endosomal escape.
Conclusions:
- Polymer blending offers a facile and high-throughput approach to identify optimal polymeric delivery systems for nucleic acid therapeutics.
- The combination of morpholino ethyl acrylamide (M) and dimethyl amino ethyl acrylamide (D) in blended micelles significantly enhances ASO transfection efficiency.
- Micelles containing D utilize the proton sponge effect for endosomal escape, a mechanism modulated by the inclusion of M.
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