Dye-Conjugated Polycationic Polymer for Tissue Visualization
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Solution Overview
Problem
Current methods for visualizing tissue structures, particularly glomeruli in kidneys, face challenges such as denaturation and removal of lipid structures during the clearing process, leading to inaccurate counting and the need for expensive MRI equipment, which is problematic during proteinuria.
Innovation Solution
A chemical compound comprising a polycationic polymer, specifically polyethyleneimine, coupled with a dye, is used to visualize glycosamine-containing structures within biological samples, allowing for non-denaturing staining and deep penetration analysis without interfering with immunostaining, and enabling visualization using microscopy instead of MRI.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If clearing technologies are used to remove lipids from tissues, then optical transparency is improved for three-dimensional analysis, but target structures may be denatured or lipid structures like cell membranes are removed altogether
Solution Approach 1:
The polycationic polymer is applied to the tissue structures before the clearing process to establish protective binding. This preliminary staining with polycationic polymers (e.g., poly-L-lysine, chitosan, polyallamine) ensures that target structures are marked and protected before lipid removal, preventing denaturation and maintaining structural integrity during the clearing process
2Measurement precision
If cationic ferritin is used with MRI to count glomeruli, then glomerular visualization is achieved, but during proteinuria the ferritin passes the basal membrane causing false signals that cannot be overcome by segmentation
Solution Approach 1:
Instead of using MRI with cationic ferritin, the invention uses optical microscopy with polycationic polymer stains that create visible copies or representations of glomerular structures. The polycationic polymers bind to and highlight glomerular structures, allowing accurate counting and measurement through optical imaging without the penetration issues of ferritin during proteinuria
Solution Approach 2:
The invention replaces the MRI magnetic field detection system with an optical microscopy system. By substituting magnetic resonance imaging with optical imaging using polycationic polymer stains, the method achieves glomerular visualization and counting without the false signals caused by ferritin translocation during proteinuria
3Measurement precision
If fluorescently labeled antibodies or lipophilic dyes are used for labeling, then target structures can be visualized, but these methods may interfere with immunostaining or be removed during clearing
Solution Approach 1:
The polycationic polymers provide homogeneous staining of target structures through electrostatic binding, creating uniform labeling that does not interfere with subsequent immunostaining procedures. This homogeneous polycationic staining approach maintains compatibility with multiple imaging modalities and subsequent antibody-based labeling
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
This approach allows for high-resolution visualization of glycosamine-containing structures and glomeruli, overcoming the limitations of existing methods by providing a cost-effective and accurate means to determine glomerular number and size without denaturing the structures, and is effective even in cases of proteinuria.
Implementation Method 1
Polymers of ethyleneimine, in particular the various forms of polyethyleneimine (PEI), have various technical uses. In life sciences, PEI and its derivatives have in particular been used for precipitating nucleic acids and for transfecting cells with DNA
Data Source
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AI summary
The present invention relates to a chemical compound comprising (i) a polycationic polymer, coupled to (ii) a dye. The present invention further relates to a method for visualizing a glycosamine-containing structure in a biological sample comprising a) contacting an inner lumen of said biological sample with a dye-conjugated polycationic polymer, preferably with the chemical compound according to the present invention; b) tissue-clearing said biological sample; and, thereby, c) visualizing an internal glycosamine-containing structure in said biological sample. The present invention also relates to a method for determining the number and/or size of glomeruli in a kidney or a sample thereof making use of the method for visualizing a glycosamine-containing structure; and also relates to kits and uses related to said chemical compounds and said methods.