Photosensitizer and chelating agent combinations for use as insecticides
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Solution Overview
Problem
Existing insecticides face issues such as toxicity to humans, limited efficacy, potential for insect resistance, high cost, and environmental harm, with some causing phytotoxicity when applied to plants.
Innovation Solution
Combining photosensitizer compounds, like porphyrins or chlorins, with chelating agents, particularly EDTA, to create a synergistic effect that increases insect mortality while minimizing phytotoxicity and reducing the amount of insecticide needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If common insecticides are applied to control insect pests, then insect mortality increases, but toxicity to humans and environmental harm increase
Solution Approach 1:
The patent uses photosensitizers as intermediary substances that require light activation to become toxic to insects. The photosensitizers themselves are non-toxic until activated by light, at which point they generate reactive oxygen species that kill insects. This intermediary mechanism allows selective toxicity - the substance is harmless during application and storage but becomes highly toxic only when activated by light on the insect host, thereby reducing human and environmental exposure to toxic chemicals.
Solution Approach 2:
The patent exploits parameter changes in the photosensitizer molecules when exposed to light. The photosensitizers undergo photochemical transformation when activated by light, changing from a stable, non-toxic state to an activated state that generates reactive oxygen species. This parameter change (from ground state to excited state) enables the substance to switch between toxic and non-toxic conditions, allowing safe application that only becomes harmful to insects upon light activation.
2Reliability
If photosensitizer compounds are used as insecticides, then insect mortality increases, but the amount of insecticide required is high
Solution Approach 1:
The patent combines photosensitizer compounds with chelating agents in a synergistic formulation. The chelating agents enhance the photosensitizer's ability to generate reactive oxygen species and improve its stability and uptake by insects. This combination allows the photosensitizer to be more effective at lower concentrations, reducing the total quantity of active ingredient needed while maintaining or improving insect mortality rates.
Solution Approach 2:
The patent creates a composite insecticide formulation consisting of photosensitizer compounds combined with chelating agents. This composite material leverages the complementary properties of both components - the photosensitizer's light-activated toxicity and the chelating agent's ability to enhance stability, solubility, and bioavailability. The composite formulation achieves superior efficacy at lower concentrations compared to using photosensitizers alone, thereby reducing the quantity of substance required.
3Reliability
If higher doses of photosensitizers are applied to increase insect mortality, then insect survival decreases, but phytotoxicity to plants increases
Solution Approach 1:
The patent employs light as an intermediary activation mechanism that provides selective toxicity. Photosensitizers applied to plants at doses that would be phytotoxic remain inactive in the dark. When insects feed on the treated plants, they concentrate the photosensitizer in their bodies, and subsequent light exposure activates the photosensitizer specifically within the insect, generating reactive oxygen species that kill the insect without harming the plant. This intermediary light-activation step enables high doses to be applied safely to plants while achieving high insect mortality.
Solution Approach 2:
The patent achieves selective toxicity through local quality differences between plants and insects. Plants possess enzymatic systems and cellular structures that can metabolize or compartmentalize photosensitizers, making them relatively resistant to photoactivation damage. Insects lack these protective mechanisms, making them highly susceptible to photosensitizer activation. This local quality difference allows the use of higher photosensitizer doses that selectively harm insects while leaving plants unharmed.
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 combination of photosensitizers and chelating agents effectively lowers insect survival rates with minimal impact on plants, offering a safer and more efficient pest control method.
Implementation Method 1
a photosensitizer compound, such as a porphyrin or a reduced porphyrin compound... that generates reactive oxygen species in the presence of light
Implementation Method 2
a chelating agent... which forms stable complexes with metal ions
Data Source
AI summary
A method for controlling insect pests on a plant is provided. The method includes applying to the plant and/or to the insect pests a combination comprising: a nitrogen-bearing macrocyclic compound which is a photosensitizer that generates reactive oxygen species in the presence of light, the photosensitizer being selected from the group consisting of a porphyrin, a reduced porphyrin and a mixture thereof; and a chelating agent which is an aminopolycarboxylic acid compound or an agriculturally acceptable salt thereof; and exposing the plant to light in the presence of the insect pests to activate the nitrogen-bearing macrocyclic compound and generate reactive oxygen species.