Si-Rhodamine Dye Membrane Permeability for Living Cell Imaging
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Solution Overview
Problem
Current fluorophores with excitation and emission maxima above 600 nm are membrane-impermeable, making it difficult to achieve specific labeling of proteins in living cells, requiring invasive methods like microinjection or electroporation for biomolecular imaging.
Innovation Solution
Development of Si-rhodamine derivatives with a carboxyl group at the 2-position of the benzyl ring, enhancing membrane permeability and allowing for specific labeling of proteins like SNAP-tag fusion proteins without the need for invasive methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If fluorophores with excitation and emission maxima above 600 nm are used, then phototoxicity is minimized and tissue penetration is increased, but membrane permeability is lost requiring invasive introduction methods
Solution Approach 1:
The patent modifies the chemical structure of rhodamine dyes by replacing the oxygen atom in the xanthene ring with silicon (Si) or germanium (Ge), which induces a bathochromic shift to excitation and emission wavelengths above 600 nm while simultaneously introducing a carboxyl group at the 2-position of the benzyl ring to enhance membrane permeability, thus resolving the contradiction between reduced phototoxicity and maintained ease of cellular uptake
2Object-affected harmful factors
If fluorophores with excitation and emission maxima above 600 nm are used, then background autofluorescence is reduced, but invasive introduction methods such as microinjection or electroporation are required
Solution Approach 1:
The structural modification of replacing oxygen with silicon or germanium in the xanthene ring and adding a carboxyl group at the 2-position of the benzyl ring achieves a dual effect: shifting emission to above 600 nm to reduce background autofluorescence, and enhancing membrane permeability to enable simple diffusion-based cellular uptake, thereby eliminating the need for complex invasive introduction methods
3Ease of operation
If regular rhodamine derivatives are used, then membrane permeability is maintained, but excitation and emission wavelengths are below 600 nm causing increased phototoxicity and background fluorescence
Solution Approach 1:
The patent applies parameter changes by substituting the oxygen atom with silicon or germanium (changing atomic size and electronegativity) and adding a carboxyl group at a specific position, which simultaneously shifts the emission wavelength above 600 nm to reduce phototoxicity while preserving and even enhancing membrane permeability properties
4Length of moving object
If fluorophores with long wavelengths above 600 nm are used, then tissue penetration is increased, but membrane impermeability prevents specific labeling in living cells
Solution Approach 1:
The chemical structure modification of replacing oxygen with silicon or germanium and introducing a carboxyl group at the 2-position of the benzyl ring achieves a bathochromic shift to wavelengths above 600 nm for enhanced tissue penetration, while the carboxyl group confers membrane permeability that enables specific labeling of proteins in living cells through passive diffusion
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 Si-rhodamine derivatives enable efficient and specific labeling of proteins in living cells, demonstrating superior permeability and biocompatibility, and can be used for various biomolecular imaging applications beyond SNAP-tag fusion proteins.
Implementation Method 1
the fluorophore absorbs and admits light at long wavelengths, preferentially above 600 nm
Implementation Method 2
Synthetic fluorophores are important tools in chemistry and biology. One of the main applications is their use as molecular probes in biomolecular imaging
Implementation Method 3
An important feature of these fluorophores is the presence of a carboxyl group at the 2-position of the benzyl ring which dramatically increases membrane permeability
Data Source
AI summary
The invention pertains to a near-infrared fluorescent dye that is cell permeable and can be attached to selected proteins in living cells. The dye has the general formulaor its corresponding spirolactonewhereinY is chosen from the group consisting of Si, Ge and Sn;R0 is —COO− or COOH;R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11, R12, R13, R14, R15 and R16 are substituents, including hydrogen, independently from each other.The dye (i) absorbs and emits light at wavelengths above 600 nm; (ii) possesses high photostability; (iii) has high extinction coefficients and high quantum yields; (iv) can be derivatized with different molecules; and (v) is membrane-permeable and shows minimal background binding to biomolecules and biomolecular structures.