Poly(amine-co-ester) Nanoparticles for siRNA Delivery
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Solution Overview
Problem
Current siRNA delivery platforms face challenges such as instability, rapid degradation, poor efficacy, high cytotoxicity, and inability to sustain gene silencing due to their size and negative charge, limiting their therapeutic potential.
Innovation Solution
Development of poly(amine-co-ester) or poly(amine-co-amide) polymers forming solid core nanoparticles, which stabilize siRNA and allow for sustained release by increasing the hydrophobic monomer content, reducing cytotoxicity, and enhancing encapsulation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If traditional siRNA delivery platforms are used, then siRNA can be delivered to cells, but the siRNA is rapidly degraded by serum enzymes and intracellular RNAses, resulting in poor stability and inability to sustain gene silencing
Solution Approach 1:
The patent uses poly(amine-co-ester) polymers as intermediary carriers to protect siRNA from degradation by enzymes. The polymer forms a protective complex with siRNA, preventing contact with degrading enzymes while maintaining siRNA functionality, thereby extending its circulation time and sustaining gene silencing effects
Solution Approach 2:
The invention creates composite nanoparticle systems combining poly(amine-co-ester) polymers with siRNA. This composite structure provides both the protective matrix of the polymer and the functional siRNA, resulting in enhanced stability and sustained release capabilities that neither component could achieve alone
2Duration of action of moving object
If siRNA is administered repeatedly to maintain gene silencing, then sustained silencing can be achieved, but the large size and negative charge of siRNA prevent it from diffusing readily across the cell plasma membrane
Solution Approach 1:
The cationic poly(amine-co-ester) polymer acts as a mediator that facilitates siRNA entry into cells. The positively charged polymer neutralizes the negative charge of siRNA and interacts with the cell membrane, enabling endocytosis and intracellular delivery that would otherwise be impossible for naked siRNA
Solution Approach 2:
The patent modifies the physical-chemical parameters of siRNA by complexing it with polymers of specific molecular weights and charge densities. This changes the effective size, charge, and surface properties of the siRNA complex, enabling it to interact with cell membranes and be internalized by cells
3Reliability
If existing delivery platforms are used to overcome delivery challenges, then some delivery efficacy can be achieved, but they exhibit high cytotoxicity
Solution Approach 1:
The patent optimizes parameters including polymer molecular weight (5,000-50,000 Da), lactone content (30-100%), and hydrophobic monomer content to achieve the optimal balance between delivery efficacy and cytotoxicity. These parameter optimizations result in reduced cellular toxicity while maintaining effective siRNA delivery
Solution Approach 2:
The use of biocompatible poly(amine-co-ester) polymers with specific compositions creates a safer composite material system compared to traditional cationic lipids or polymers. The composite structure provides effective delivery while the specific polymer composition minimizes cytotoxic effects
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The nanoparticles provide improved stability, increased siRNA loading, and sustained intracellular release of nucleic acids, achieving long-term gene silencing with reduced cytotoxicity and enhanced transfection efficiency compared to traditional platforms.
Implementation Method 1
the content of a hydrophobic monomer in the polymer is increased relative the content of the same hydrophobic monomer when forming polyplexes in order to form nanoparticles rather than polyplexes
Data Source
AI summary
Polymers including poly(amine-co-ester), poly(amine-co-amide), or a combination thereof, and nanoparticles, particularly solid core nanoparticles, formed therefrom are provided. Solid core nanoparticles fabricated from hydrophobic polymers often require the presence of cationic complexing agents to stabilize negatively charged active agents such as siRNA. However, complexing agents are optional in the disclosed formulations because the nanoparticles contain cationic amines to stabilize negatively charged nucleic acids and hydrophobic domains to condense the nucleic acid into the core of the formed nanoparticles, thus improving encapsulation efficiency. This increase in nucleic acid loading allows the disclosed solid core nanoparticles to deliver more nucleic acid per cell without increasing total polymer delivered, further reducing cytotoxicity. Pharmaceutical compositions including an effective amount of the nanoparticles are also provided, and be used, for example, for in vitro and in vivo delivery of nucleic acids.