Citrate-Based Biodegradable Optical Fiber for Tissue Imaging
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Solution Overview
Problem
Biomedical optical technologies face challenges due to the turbidity of biological tissue, which hinders light delivery and collection, especially with traditional non-degradable and brittle silica fibers, and existing biodegradable materials lack suitable optical, mechanical, and biological functionalities.
Innovation Solution
A biodegradable polymeric step-index optical fiber using a citrate-based material platform with a core and cladding made from citric acid and different monomers, allowing for tuned refractive indices, mechanical properties, and biodegradation rates, ensuring low optical loss and mechanical flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If traditional silica fibers are used for light delivery, then optical transmission efficiency is improved, but biodegradability and mechanical flexibility deteriorate
Solution Approach 1:
The patent employs composite polymeric materials consisting of a core made from poly(ethylene glycol) diacrylate crosslinked with citric acid, and a cladding layer made from poly(L-lactic acid) or poly(D,L-lactic acid) crosslinked with citric acid. This composite structure enables simultaneous achievement of optical transmission efficiency through the core and biodegradability through the cladding layer, resolving the contradiction between maintaining optical performance and enabling biodegradation.
2Ease of manufacture
If single material waveguides are used, then manufacturing simplicity is improved, but optical loss increases due to lack of intrinsic cladding layer
Solution Approach 1:
The waveguide is segmented into two distinct functional layers: a core region for light propagation and a cladding layer for optical confinement. The core is formed by crosslinking poly(ethylene glycol) diacrylate with citric acid, while the cladding is formed by crosslinking poly(L-lactic acid) or poly(D,L-lactic acid) with citric acid. This segmentation provides intrinsic optical confinement to reduce loss while maintaining relatively simple manufacturing through sequential coating and crosslinking processes.
3Reliability
If biodegradable polymeric materials are used, then biocompatibility and biodegradability are improved, but mechanical strength and optical performance deteriorate
Solution Approach 1:
The mechanical strength and optical properties of the biodegradable polymeric fiber are optimized by controlling crosslinking parameters. Citric acid crosslinking density is adjusted to achieve the desired balance between mechanical strength and biodegradability. The core uses poly(ethylene glycol) diacrylate with specific molecular weight and crosslinking ratio, while the cladding uses poly(L-lactic acid) or poly(D,L-lactic acid) with controlled crosslinking, enabling tailored mechanical properties while maintaining biocompatibility and biodegradability.
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 citrate-based fiber enables efficient light transmission and biocompatibility, with potential for long-term monitoring and imaging in the body, suitable for applications like tissue regeneration, drug delivery, and optogenetic stimulation, while maintaining mechanical integrity and programmable biodegradability.
Implementation Method 1
biocompatible step-index fiber optical waveguide consisting of a PEG core and an alginate hydrogel cladding
Implementation Method 2
Citrate-based materials are a group of designable biodegradable elastomers that can be completely degraded in the body
Data Source
AI summary
A biocompatible and biodegradable polymeric step-index optical fiber includes a core and a cladding around the core. The core is made from a core material fabricated by bonding a citric acid and at least a first monomer using a synthesis process. The cladding is made from a cladding material fabricated by bonding the citric acid and at least a second monomer using the synthesis process. The core has a refractive index higher than that of the cladding, while a difference between an initial modulus of the core and the cladding is preferably less than 30% and a difference between the biodegradation rates of the core and cladding is preferably less than 30% after about 4 weeks. Optical properties of the core and cladding are tunable by adjusting monomer ratios, choices of monomers or cross-linking degrees.