Chitosan Protective Coating Sprayability and Stability
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Solution Overview
Problem
Chitosan solutions used for tissue repair or drug delivery often have high viscosity when crosslinked, making them unsuitable for spray application, and rapid crosslinking agents may be harmful or impractical.
Innovation Solution
A two-part composition comprising a partially crosslinked polysaccharide and a further crosslinker, which are mixed just before application to form a fluid that can be sprayed onto a body surface, allowing for the formation of a conformal protective layer without premature gelation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If chitosan is crosslinked prior to delivery to prevent premature disappearance, then the likelihood of premature disappearance is reduced, but the viscosity becomes too high for spray application
Solution Approach 1:
The crosslinking process is segmented into two stages: pre-crosslinking to form a stable polymer structure, and post-application crosslinking to achieve final stability at the treatment site. This allows the material to be sprayable during application while ultimately achieving the desired stability.
Solution Approach 2:
Partial crosslinking is performed in advance to create a pre-crosslinked chitosan that maintains sufficient fluidity for spray application while having reduced tendency to drain or resorb prematurely. The remaining crosslinking occurs after application to complete the stabilization process.
2Ease of operation
If chitosan is crosslinked in situ by combining with a crosslinker following delivery, then spray application is enabled, but the crosslinking reaction proceeds too slowly for practical use
Solution Approach 1:
The chitosan is pre-crosslinked to a controlled extent before application, which accelerates the overall process by reducing the amount of crosslinking needed after application. This preliminary crosslinking creates a structure that requires less additional crosslinking time to achieve practical stability.
Solution Approach 2:
The degree of pre-crosslinking is optimized to balance sprayability and crosslinking speed. By controlling the pre-crosslinking parameters, the material achieves sufficient stability while maintaining sprayable viscosity, and the remaining crosslinking proceeds at a practical rate.
3Productivity
If potentially harmful crosslinking agents are employed to achieve practical crosslinking speed, then crosslinking proceeds fast enough for practical use, but harmful effects are introduced
Solution Approach 1:
The harmful aspects of rapid crosslinking agents are extracted or avoided by using a two-stage crosslinking approach with biocompatible crosslinkers. The pre-crosslinking stage uses controlled conditions with safe agents, and the post-application stage completes the process without requiring harsh chemicals.
Solution Approach 2:
The need for rapid crosslinking is converted into a benefit by using the pre-crosslinked structure to accelerate the overall process while allowing the use of safer crosslinking agents. The pre-crosslinked chitosan provides a head start that makes the use of potentially harmful rapid crosslinkers unnecessary.
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
Enables the creation of a thin, adherent, and biocompatible protective layer on body tissues that reduces bacterial adhesion, promotes healing, and prevents premature runoff, while minimizing the use of harmful crosslinking agents.
Implementation Method 1
the first part comprising a partially crosslinked polysaccharide and the second part comprising a further crosslinker for the polysaccharide
Implementation Method 2
Hydration or dilution may occur once the spray-applied solution reaches an intended treatment site
Data Source
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AI summary
Body tissue and structures may be protected using a fluid containing a mixture of partially crosslinked polysaccharide and a further crosslinker. The mixture desirably is sprayable, forms a fluid protective layer via in situ crosslinking, desirably does not drip or run from a treatment site, and may avoid the use of more rapidly curing but potentially less bioacceptable crosslinkers at the treatment site.