Systems and methods for controlling temperature of small volumes
Inventors
Kasianowicz, John J. • Reiner, Joseph E. • Balijepalli, III, Arvind K. • Robertson, Joseph W. • Burden, Daniel L. • Burden, Lisa
Assignees
National Institute of Standards and Technology NIST • United States Department of Commerce
Publication Number
US-9921174-B2
Publication Date
2018-03-20
Expiration Date
2033-11-06
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Abstract
Systems and methods for controlling the temperature of small volumes such as yoctoliter volumes, are described. The systems include one or more plasmonic nanostructures attached at or near a nanopore. Upon excitation of the plasmonic nanostructures, such as for example by exposure to laser light, the nanoparticles are rapidly heated thereby causing a change in the ionic conductance along the nanopore. The temperature change is determined from the ionic conductance. These temperature changes can be used to control rapid thermodynamic changes in molecular analytes as they interact with the nanopore.
Core Innovation
The invention provides systems and methods for controlling and measuring the temperature of extremely small volumes, such as yoctoliter volumes, by using plasmonic nanostructures attached proximate to a nanopore. Upon excitation with light, such as laser light, the plasmonic nanostructures rapidly heat, causing localized temperature changes that modify the ionic conductance through the nanopore. These changes in ionic conductance are measured to determine the temperature or temperature changes at the nanopore in real-time.
The system solves problems associated with prior temperature jump (T-jump) methods which required bulk heating of relatively large volumes and post-processing of optical signals to estimate temperature, limiting temporal resolution and control of complex temperature profiles. This invention enables precise control of temperature changes in volumes on the single-molecule scale and provides a direct electrical measurement of temperature using the nanopore’s ionic conductance as a thermometer.
By tethering metallic nanoparticles—usually gold nanoparticles—to nanopores such as protein ion channels formed by α-hemolysin, and exciting these nanoparticles with laser light at or near their surface plasmon resonance, the temperature within and near the nanopore can be rapidly increased and monitored. This localized heating affects the physical and chemical behavior of molecular analytes like polymers as they interact with the nanopore, thus enabling studies of single molecule thermodynamics and kinetics with unprecedented spatial and temporal resolution.
Claims Coverage
The patent includes one independent claim focusing on a method for analyzing polymers using plasmonic nanostructures associated with nanopores. The main inventive features encompass the arrangement, excitation, temperature control, and analytic use of temperature changes within the nanopore environment.
Method for analyzing polymers using plasmonic nanostructure-induced temperature changes at a nanopore
The method comprises providing plasmonic nanostructures; affixing them proximate to a nanopore on a surface; disposing a polymer in the nanopore; emitting light of sufficient intensity and wavelength to excite the plasmonic nanostructures and induce localized temperature changes; and analyzing the polymer by use of these temperature changes within the nanopore.
Analyzing polymers by assessing physical, chemical, thermodynamic, and kinetic changes induced by controlled temperature variation
The analyzing step includes assessing at least one of the physical changes to polymers, chemical changes to polymers, thermodynamic properties of polymers, and kinetic properties of polymers as affected by the induced localized temperature changes within the nanopore.
Use of plasmon resonance excitation to generate localized heating
During the light emission step, the light is absorbed at or near the surface plasmon resonance of the nanostructures, causing an increase in their temperature and heating the surrounding nanopore environment.
Attachment and configuration of metallic nanoparticles to biological layers defining nanopores
The method includes using metallic nanoparticles tethered to a biological layer that defines the nanopore, with tethering performed by oligomers such as oligonucleotides having 10 to 500 repeating units, to ensure proximity of plasmonic structures to the nanopore.
Utilization of various light sources to excite plasmonic nanostructures
The emitted light used to excite the nanostructures can come from lasers, incandescent light sources, light emitting diodes, or arc lamps, providing flexibility in excitation methods.
These inventive features collectively describe a method that combines the precise localized heating enabled by plasmonic nanostructures near nanopores, real-time measurement of temperature changes via ionic conductance, and the subsequent analysis of polymer behavior under these controlled thermal conditions.
Stated Advantages
Provides rapid and localized temperature control and measurement at the single molecule scale inside nanopores.
Enables direct, real-time electrical measurement of temperature changes via ionic conductance without the need for post-processing.
Allows precise temporal control of complex temperature profiles, overcoming limitations of previous bulk heating and optical estimation methods.
Facilitates enhanced sensitivity and specificity in single molecule thermodynamics and kinetic studies due to localized heating effects.
Improves nanopore-based sensors by adding temperature as a controllable variable for analyzing molecular interactions.
Documented Applications
Analyzing polymers by assessing their physical, chemical, thermodynamic, and kinetic properties within nanopores under controlled temperature changes.
Single molecule thermodynamics and kinetics studies using nanopores combined with localized plasmonic heating.
Use in nanopore sensors for detecting and characterizing molecular species including polymers by modulating temperature in the immediate nanopore environment.
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