Poly(spermine acrylamide) Nanocarriers for siRNA Delivery
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Solution Overview
Problem
Current methods for delivering siRNA face challenges such as inefficient intracellular delivery, rapid chemical degradation, and immunological responses, particularly with viral vectors, which are associated with safety concerns and low transfection efficiencies of non-viral systems, necessitating the development of a non-toxic, biocompatible nanocarrier that can overcome extracellular and intracellular barriers.
Innovation Solution
The synthesis of poly(spermine acrylamide) and poly(spermine acrylamide-co-N-alkylacrylamide) polymers through free radical polymerization or reversible addition-fragmentation chain transfer polymerization, followed by treatment with tri-boc spermine, to create a nanocarrier with amphiphilic properties for targeted siRNA delivery, enhancing cellular uptake and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If viral vectors are used for siRNA delivery, then transfection efficiency is improved, but safety concerns arise due to immunogenicity and mutagenicity
Solution Approach 1:
The patent uses poly(spermine acrylamide) as an intermediary carrier between siRNA and cells. This polymer mediates the delivery process by forming polyplexes with siRNA, protecting them from degradation, and facilitating cellular uptake without the safety issues of viral vectors. The polymer acts as a safe intermediary that bridges the gap between siRNA and target cells.
Solution Approach 2:
The patent employs synthetic poly(spermine acrylamide) polymers as disposable, non-viral delivery vehicles. Unlike viral vectors that can integrate into genomes and cause long-term safety issues, these synthetic polymers are designed for single-use delivery without persistent biological effects, eliminating immunogenicity and mutagenicity concerns.
2Object-affected harmful factors
If non-viral vectors like PEI are used, then safety is improved, but transfection efficiency decreases
Solution Approach 1:
The patent modifies polymer parameters by using poly(spermine acrylamide) with specific molecular weights (10-100 kDa) and controlled amine densities. This optimization of physical and chemical parameters achieves the right balance between buffering capacity (for endosomal escape) and reduced cytotoxicity, overcoming the limitations of conventional PEI.
Solution Approach 2:
The patent creates composite polyplex structures by combining poly(spermine acrylamide) with siRNA. This composite material leverages the beneficial properties of both components: the polymer provides protection and cellular uptake enhancement, while siRNA delivers the therapeutic payload, achieving high transfection efficiency with low toxicity.
3Device complexity
If siRNA is administered naked, then simplicity is improved, but stability decreases due to rapid chemical degradation by serum nucleases
Solution Approach 1:
The patent uses a nested structure where siRNA is encapsulated within poly(spermine acrylamide) polyplexes. The polymer forms a protective shell around the siRNA, nesting the fragile nucleic acid within a stable polymeric matrix that shields it from serum nucleases and other degradation factors.
Solution Approach 2:
The poly(spermine acrylamide) polymer serves as an intermediary protective layer between siRNA and the harsh biological environment. This intermediary structure prevents direct contact between siRNA and degrading enzymes like serum nucleases, maintaining siRNA stability during circulation.
4Reliability
If high amine density polymers are used, then transfection efficiency is improved, but cytotoxicity increases
Solution Approach 1:
The patent optimizes the amine density parameter of poly(spermine acrylamide) to achieve the minimum necessary for effective transfection while minimizing cytotoxicity. By controlling the molecular weight and composition, the polymer provides sufficient buffering capacity for endosomal escape without excessive amine density that would cause cellular damage.
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 resulting nanocarriers exhibit improved biocompatibility, reduced cytotoxicity, and efficient siRNA encapsulation and delivery, outperforming commonly used polymers like PEI in terms of cellular uptake and stability, while maintaining low cytotoxicity and immunogenicity.
Implementation Method 1
synthesizing and employing N-acryloxysuccinimide and linear or branched N-alkylacrylamide that are reacted via free radical polymerization using a polymerization initiator
Implementation Method 2
synthesizing and employing N-acryloxysuccinimide and linear or branched N-alkylacrylamide that are reacted via reversible addition-fragmentation chain transfer polymerization using a chain-transfer agent and a polymerization initiator
Implementation Method 3
treating the obtained polymers and/or copolymers in step b) with at least 0.1 equivalent of tri-boc spermine per N-acryloxysuccinimide-repeating unit and obtaining poly(spermine acrylamide) and/or poly(spermine acrylamide-co-N-alkylacrylamide) polymers
Implementation Method 4
Especially cationic polymers are promising delivery systems due to their electrostatic interactions with siRNA resulting in polyplexes
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
The present invention relates to a process for the synthesis of poly(spermine acrylamide) and/or poly(spermine acrylamide-co-N-alkylacrylamide), the process comprising the following steps: a) Reacting a mixture of N-acryloxysuccinimide with N-alkylacrylamide, and b) Obtaining poly(N-acryloxysuccinimde) polymers, poly(N-alkylacrylamide) polymers and/or copolymers with varying ratios of N-acryloxysuccinimide and N-alkylacrylamide, and c) Treating the obtained polymers and/or copolymers of step b) with at least 0.1 equivalent of tri-boc spermine per N-acryloxysuccinimiderepeating unit and obtaining poly(spermine acrylamide) and/or poly(spermine acrylamide-co-N-alkylacrylamide) polymers.