Fluorogenic Probes for H2O2 via Boronate Deprotection
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Solution Overview
Problem
Current H2O2-responsive probes face challenges such as interfering background fluorescence, need for external activating enzymes, lack of water solubility, and excitation profiles that can damage biological samples, limiting their effectiveness in selectively detecting hydrogen peroxide in living cells.
Innovation Solution
Development of pro-fluorescent compounds that undergo chemoselective boronate deprotection to create highly selective and sensitive fluorescent probes for H2O2, allowing for biological compatibility and imaging of intracellular H2O2 concentrations with minimal photodamage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If current H2O2-responsive probes are used, then H2O2 detection is achieved, but interfering background fluorescence from competing ROS occurs
Solution Approach 1:
The probe uses a pro-fluorescent design where the fluorophore is masked before activation. The boronate group is pre-installed on the fluorophore to block fluorescence, and only after H2O2-triggered deprotection removes the boronate group does fluorescence activate. This preliminary masking action prevents background fluorescence from competing ROS while ensuring selective H2O2 response.
Solution Approach 2:
The boronate group serves as an intermediary protective element that selectively binds to the fluorophore in the presence of H2O2. This intermediary mechanism allows the probe to distinguish H2O2 from other ROS, as the boronate-deprotecting reaction is specifically triggered by H2O2 oxidation, thereby eliminating interference from competing ROS species.
2Measurement precision
If traditional fluorescent probes are used, then H2O2 detection is possible, but excitation profiles cause photodamage to biological samples
Solution Approach 1:
The probe is designed with visible excitation and emission profiles (excitation maximum around 405 nm, emission maximum around 520 nm), shifting from UV to visible light range. This parameter change in the optical spectrum reduces photodamage to biological samples while maintaining H2O2 detection capability, as visible light is less energetic and less damaging to cellular structures.
3Measurement precision
If existing H2O2 probes are used, then fluorescence signaling is achieved, but water solubility is insufficient requiring organic co-solvents
Solution Approach 1:
The probe incorporates a sulfonated coumarin fluorophore conjugated to a boronate-containing moiety, creating a composite molecular structure that combines hydrophilic sulfonate groups with the fluorescent coumarin core. This composite design enhances water solubility while maintaining fluorescence properties, eliminating the need for organic co-solvents and improving biocompatibility for intracellular imaging.
4Measurement precision
If current probes are used, then H2O2 detection is achieved, but external activating enzymes are required increasing system complexity
Solution Approach 1:
The probe employs a self-activating mechanism where H2O2 directly triggers the deprotection of the boronate group from the fluorophore without requiring external enzymes. The H2O2 molecule itself serves as the activating agent, oxidizing the boronate group to release the fluorophore and generate fluorescence. This self-service approach simplifies the system by eliminating the need for external activating enzymes or complex enzymatic systems.
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 probes provide excellent selectivity for H2O2 over competing ROS, enabling accurate imaging of micromolar changes in H2O2 concentrations in living cells, including hippocampal neurons, using confocal and two-photon microscopy, with visible excitation and emission profiles that avoid autofluorescence.
Implementation Method 1
conversion of a pro-fluorescent species into a fluorescent probe by chemoselective deprotection of the pro-fluorescent species
Implementation Method 2
fluorescent probes for reactive oxygen species
Data Source
AI summary
The present invention provides a novel class of fluorogenic probes for reactive oxygen species. Exemplary probes of the invention utilize a boronate deprotection mechanism to provide high selectivity and optical dynamic range for detecting H2O2 in aqueous solution over similar reactive oxygen species (ROS) including superoxide, nitric oxide, tert-butyl hydroperoxide, and hydroxyl radical; Peroxyresorufin-1 (PR1), Peroxyfluor-1 (PF1), and Peroxyxanthone-1 (PX1) are first-generation probes that respond to H2O2 by an increase in red, green, and blue fluorescence, respectively. The boronate dyes are cell-permeable and can detect micromolar changes in H2O2 concentrations in living cells, including hippocampal neurons, using confocal and two-photon microscopy. The unique combination of ROS selectivity, membrane permeability, and a range of available excitation/emission colors establishes the potential value of PR1, PF1, PX1, and related probes for interrogating the physiology and pathology of cellular H2O2.