pH/Reduction Responsive Polyamino Acid Zwitterionic Nanoparticles
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Solution Overview
Problem
Current zwitterionic polymers used in drug delivery are non-biodegradable, lack pH/reductive responsiveness, and have issues with incomplete drug release and adverse side effects due to residual polymer degradation, and existing methods for preparing polyamino acid nanoparticles are complex and difficult to control.
Innovation Solution
A method involving ring-opening polymerization of polyglutamic acid, introduction of L-lysine to form zwitterionic ions, and cross-linking with cysteamine to create pH/reduction responsive polyamino acid zwitterionic nanoparticles, which are biocompatible and controllable in size and molecular weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If non-biodegradable zwitterionic polymers are used as drug carriers, then circulation time and EPR effect are improved, but incomplete drug release and adverse side effects occur due to residual polymer degradation
Solution Approach 1:
The patent changes the chemical composition parameters of the polymer by incorporating biodegradable units (polyglutamic acid, polylysine) alongside zwitterionic components, transforming the polymer from non-biodegradable to biodegradable while maintaining the desired circulation properties and eliminating harmful residual degradation
Solution Approach 2:
The patent creates composite polymer structures combining biodegradable polymers (polyglutamic acid, polylysine) with zwitterionic components, achieving a material that possesses both the circulation enhancement properties of zwitterionic polymers and the biocompatibility of biodegradable materials
2Reliability
If existing zwitterionic polymers are used, then hydration ability and bacterial adhesion resistance are improved, but pH/reductive responsiveness is lost making drug release control difficult
Solution Approach 1:
The patent introduces disulfide bonds at specific locations within the polymer structure (through cystamine crosslinking), creating localized reduction-responsive sites that enable controlled drug release while maintaining the overall zwitterionic properties for hydration and anti-adhesion
3Productivity
If direct amination of polyglutamic acid with cysteamine is used, then nano microgels are formed quickly, but molecular weight and particle size are difficult to control
Solution Approach 1:
The patent performs preliminary actions by first synthesizing polyglutamic acid and polylysine with controlled molecular weights through ring-opening polymerization, and pre-functionalizing them with appropriate side chain groups before the crosslinking step, thereby enabling better control over final nanoparticle size and properties
Solution Approach 2:
The patent segments the synthesis process into distinct stages: polymerization of controlled molecular weight, side chain functionalization, and crosslinking, allowing independent optimization and control of each step to achieve both high productivity and manufacturing precision
4Reliability
If complex preparation methods are used for polyamino acid nanoparticles, then zwitterionic structure is achieved, but preparation time and process complexity increase
Solution Approach 1:
The patent merges multiple functions into a single crosslinking step: cystamine crosslinking simultaneously forms the nanoparticle structure, introduces disulfide bonds for reduction responsiveness, and creates zwitterionic ions through reaction with carboxyl groups, thereby simplifying the overall preparation process while achieving multiple desired properties
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 method produces nanoparticles that are pH and reduction sensitive, allowing for controlled drug release at tumor sites with improved biocompatibility and reduced side effects, enhancing the effectiveness of anticancer drug delivery.
Implementation Method 1
Ring-opening polymerization of γ-benzyl-L-glutamate-N-carboxylic anhydride is initiated by an aliphatic amine and performed, giving poly(γ-benzyl-L-glutamate)
Implementation Method 2
L-lysine is introduced into the side chain through a group reaction to form zwitterionic ions
Implementation Method 3
The zwitterionic polymer is crosslinked with cysteamine and is purified to obtain pH/reduction responsive polyamino acid zwitterionic nanoparticles
Implementation Method 4
The nanoparticles are also reduction sensitive since disulfide bonds are involved in the crosslinking structure
Implementation Method 5
The concentration of glutathione in tumor cells is 100 to 1000 times higher than that in body fluids or other tissues. It has a strong reductive effect on disulfide bonds
Data Source
AI summary
The invention discloses a preparation method of pH/reduction responsive polyamino acid zwitterionic nanoparticles, which belongs to the technical field of polymer synthesis and biomedical materials. In the invention aliphatic amines are used to initiate ring-opening polymerization of γ-benzyl-L-glutamate-N-carboxylic anhydride, and the obtained poly(γ-benzyl-L-glutamate) reacts with L-lysine to form azwitterionic polymer. The zwitterionic polymer is crosslinked by cysteamine, producing pH/reduction responsive polyamino acid zwitterionic nanoparticles after purification. The nanoparticles are pH responsive and resistant to non-specific protein adsorption. Because cysteamine contains disulfide bonds, the nanoparticles have sensitive reductive responsiveness and can load anticancer drugs for controlled release at the target site of cancer.