Fluorescence-based computation system
Inventors
Medintz, Igor L. • Ancona, Mario • Algar, W. Russ • Massey, Melissa M.
Assignees
Publication Number
US-11371079-B2
Publication Date
2022-06-28
Expiration Date
2037-03-24
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Abstract
Time-resolved nucleic acids include a long-lifetime FRET donor with an emission lifetime of at least one millisecond (such as a terbium complex), configured as a donor in a first FRET process, and at least one fluorescent dye with an emission lifetime of less than 100 nanoseconds configured as an acceptor in the FRET process. They can be configured as photonic wires, hybridization probes or beacons, and/or systems for computing logical operations.
Core Innovation
The invention describes time-resolved nucleic acids that utilize a long-lifetime FRET donor with an emission lifetime of at least one millisecond, exemplified by a terbium complex, configured as a donor in a first FRET process, and at least one fluorescent dye with an emission lifetime of less than 100 nanoseconds as an acceptor. These constructs are designed as photonic wires, hybridization probes or beacons, and systems for computing logical operations, enabling time-gated fluorescence measurements that improve signal detection by minimizing background fluorescence.
The problem addressed is the limitations in existing fluorescence-based nucleic acid detection and signal transduction methods, such as photobleaching, undesirable direct excitation of dyes, low FRET efficiencies, and interference from biological sample matrix fluorescence. Current DNA-organized FRET-based photonic wires are challenged by these issues, limiting their utility in applications like biosensing, photonic computing, and diagnostic assays. This invention seeks to overcome these challenges by using long-lifetime luminophores, like terbium complexes, in combination with short-lifetime fluorescent dyes to achieve improved time-gated FRET cascades with better signal-to-noise ratios and multiplexed detection capability.
The invention further identifies and exploits a "sweet spot" distance between the long-lifetime donor and the acceptor dye, balancing the FRET efficiency and measurement lag time to optimize the time-gated emission signal. The time-gated photonic wires include configurations with DNA and locked nucleic acid (LNA) segments to create thermally stable scaffolds, enabling multi-step FRET cascades initiating from the terbium donor. The system's design permits selective detection capabilities, multiplexing, operation in complex biological matrices, and photonic logic computation based on nucleic acid hybridization events.
Claims Coverage
The patent contains one independent claim that discloses a system for computing logical operations with several inventive features.
System configured for FRET-based logical computation
The system comprises a first oligonucleotide covalently attached to a long-lifetime luminophore with an emission lifetime of at least one millisecond serving as a FRET donor; at least a second oligonucleotide complementary to the first oligonucleotide; and at least one fluorescent dye with an emission lifetime of less than 100 nanoseconds as a FRET acceptor covalently attached to one of the oligonucleotides.
Optional inclusion of fluorescence quenchers
The system optionally comprises at least one quencher of fluorescence that quenches the FRET process, covalently attached to one of the oligonucleotides to modulate the emission signal.
Input-dependent FRET output
The system is configured so that an input condition based on the presence or absence of one or two oligonucleotide targets, complementary to but distinct from the oligonucleotides in the system, produces an output condition determined by the presence or absence of a FRET process between the long-lifetime luminophore and the fluorescent dye.
Optimization of donor-acceptor positioning
The long-lifetime luminophore and fluorescent dye are positioned at a "sweet spot" distance calculated to balance FRET efficiency and instrument lag time, optimizing the detectability of time-gated emission signals.
The claims encompass a DNA-based logical operation system leveraging time-resolved FRET with a long-lifetime donor and short-lifetime fluorescent acceptors, incorporating optional quenchers, input-driven FRET signal modulation, and spatial optimization of donor-acceptor distance to maximize time-gated emission for logic computations.
Stated Advantages
Time-gated measurements minimize unwanted background emission from direct excitation of fluorescent dyes, excess dye-labeled strands, or biological sample matrices.
The use of a long-lifetime luminophore such as a terbium complex improves FRET efficiency and allows multiplexing through multiple emission lines.
Incorporation of locked nucleic acid (LNA) increases the thermal stability of the nucleic acid structures.
The system provides improved signal-to-background ratios, enabling sensitive, selective, and multiplexed nucleic acid detection in complex matrices such as serum and blood.
Time-gated fluorescence-based logic operators enable molecular computation with photonic outputs in response to biochemical inputs, opening pathways to nanoscale information processing and diagnostic screening.
Documented Applications
Use as DNA/LNA-based photonic wires for efficient, multi-step FRET cascades with time-gated emission measurements.
Hybridization probes or nucleic acid beacons for selective and multiplexed detection of DNA targets, including in complex biological fluids like serum and blood.
Systems for computing logical operations (AND, OR, NAND, NOR) based on nucleic acid hybridization inputs that produce a photonic output via time-gated FRET signals.
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