Enzyme-Triggered NO Hydrogel for Tumor Radiosensitization
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Solution Overview
Problem
Current NO donor materials for cancer radiotherapy lack precise control over the quantity and duration of NO release, leading to inefficient radiosensitization and potential damage to normal cells due to rapid NO release.
Innovation Solution
A nitric oxide hydrogel is developed, comprising a gel-forming polypeptide covalently linked with a β-galactose-protected NO donor molecule, which self-assembles to release NO only under β-galactosidase catalysis, allowing for controlled and sustained NO delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If NO donor materials are used for radiosensitization, then tumor radiosensitivity is improved, but NO releases rapidly causing damage to normal cells and losing control over dosage and duration
Solution Approach 1:
The patent uses β-galactose as a protective intermediary group that masks the NO donor molecule, preventing premature NO release. The β-galactose-protected NO donor serves as an intermediate form that only releases NO when the protective group is removed by β-galactosidase enzyme in the tumor microenvironment, thus mediating between the need for NO delivery and the need to prevent harmful side effects
Solution Approach 2:
The patent changes the chemical state of the NO donor from a free, rapidly-releasing form to a protected, stable form (β-galactose conjugate). This parameter change in molecular structure fundamentally alters the release kinetics, transforming the NO donor from one that releases NO immediately to one that releases NO in a controlled, enzyme-triggered manner, thereby extending duration and controlling dosage
2Productivity
If NO is released in large amounts for maximum cytotoxicity, then tumor cell killing is enhanced, but normal cells are damaged and therapeutic window is reduced
Solution Approach 1:
The patent creates local quality differentiation by designing the NO release system to be spatially and temporally selective. The β-galactose-protected NO donor remains inert in circulation and only activates locally in the tumor microenvironment where β-galactosidase is overexpressed. This ensures high NO concentration is achieved only where needed (tumor cells), maximizing productivity while minimizing harm to normal cells through precise localization of the therapeutic effect
Solution Approach 2:
The system utilizes the endogenous β-galactosidase enzyme that is naturally overexpressed in tumor cells as a self-activating mechanism. The tumor cells themselves provide the enzymatic service needed to activate the prodrug, creating a self-directed therapeutic effect that automatically concentrates NO where the disease is present without requiring external control mechanisms
3Duration of action of stationary object
If NO donor releases NO continuously at low dosage for vascular normalization, then tumor vasculature is normalized and oxygen supply improves, but insufficient NO is available for maximum radiosensitization effect
Solution Approach 1:
The patent implements periodic action through the enzyme-triggered release mechanism. Instead of continuous low-level release or single-dose bolus release, the β-galactose-protected NO donor provides rhythmic, sustained release of NO as the enzyme progressively deconjugates the protective groups. This periodic activation maintains therapeutic NO levels over an extended period, simultaneously achieving vascular normalization (requiring continuous exposure) and radiosensitization (requiring sufficient total dose)
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 hydrogel provides localized, sustained NO release, enhancing tumor vascular normalization and radiosensitization while minimizing harm to normal cells, with precise control over NO exposure and improved biocompatibility.
Implementation Method 1
the β-Gal removes a galactose group of SupraNO, liberates the NO donor, and then releases two molecules of NO
Implementation Method 2
the β-Gal removes a galactose group of SupraNO, liberates the NO donor
Implementation Method 3
A nitric oxide hydrogel is developed, comprising a gel-forming polypeptide covalently linked with a β-galactose-protected NO donor molecule, which self-assembles to release NO
Implementation Method 4
which self-assembles to release NO only under β-galactosidase catalysis
Implementation Method 5
NO has a similar electron affinity to oxygen and can bind to free radicals that damage DNA to fix the damages
Data Source
AI summary
The present disclosure provides a nitric oxide hydrogel for promoting tumor vascular normalization and radiosensitization and a preparation method thereof. The hydrogel includes a gel-forming polypeptide for forming a hydrogel and a β-galactose-protected NO donor molecule, where the gel-forming polypeptide and the β-galactose-protected NO donor molecule are covalently linked. In the present disclosure, the preparation method has a low synthesis cost, and adopts daily essential amino acid of the human body as raw materials, showing desirable biocompatibility. The hydrogel acts as a NO reservoir for continuous NO delivery on demand, which significantly solves the problem of a short half-life of NO molecules. Most importantly, the hydrogel releases NO only under the catalysis of β-galactosidase (β-Gal), with a release amount precisely controlled by an enzyme concentration.