Device for collecting and enriching microbes

Abstract

In one aspect, devices for collecting and enriching microbes are described herein. In some embodiments, such a device comprises a shape memory gel and a plurality of nanoantennas dispersed in the gel. The nanoantennas can be non-uniformly dispersed in the gel. Additionally, the nanoantennas are operable to receive an external signal and thereby induce a local change in state of the gel, such as a local change in thermodynamic state of the gel.

Claims

1. A device for collecting and/or enriching one or more microbes, the device comprising: a shape memory gel; and a plurality of nanoantennas non-uniformly dispersed in the gel, wherein the nanoantennas are operable to receive an external signal and thereby induce a local change in state of the gel for retaining the one or more microbes in the gel.

2. The device of claim 1, wherein the local change in state is a local change in thermodynamic state of the gel.

3. The device of claim 1, wherein the gel is a crosslinked hydrogel.

4. The device of claim 1, wherein the gel comprises poly (N-isopropylacrylamide).

5. The device of claim 1, wherein the gel is a pH-responsive shape memory gel, a temperature-responsive shape memory gel, a pressure-responsive shape memory gel, a light-responsive shape memory gel, or an electrochemical-responsive shape memory gel.

6. The device of claim 1, wherein the local change in state induced by the nanoantennas is a local change in the internal energy, entropy, mass, chemical composition, fugacity, temperature, pH, pressure, and/or specific volume of the gel.

7. The device of claim 1, wherein the nanoantennas are formed from metal nanoparticles.

8. The device of claim 1, wherein the nanoantennas are present in the gel in a higher density in a peripheral region of the gel and in a lower density in an interior region of the gel.

9. The device of claim 8, wherein the peripheral region of the gel is adjacent one or more an intake side of the gel in fluid communication with a liquid analyte.

10. The device of claim 9, wherein the one or more microbes are dispersed in the liquid analyte.

11. The device of claim 1, wherein the gel is disposed in a container.

12. The device of claim 11, wherein the container is operable to place an intake side of the gel in fluid communication with a liquid analyte.

13. The device of claim 12, wherein the one or more microbes are dispersed in the liquid analyte.

14. The device of claim 1, wherein the local change comprises an increase in the density of the shape memory gel.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIGS. 1(a)-(f) illustrate steps of a method of collecting and enriching microbes according to one embodiment described herein.

DETAILED DESCRIPTION

(2) Embodiments described herein can be understood more readily by reference to the following detailed description, examples and drawings and their previous and following descriptions. Elements, apparatus and methods described herein, however, are not limited to the specific embodiments presented in the detailed description, examples and drawings. It should be recognized that these embodiments are merely illustrative of the principles of the present invention. Numerous modifications and adaptations will be readily apparent to those of skill in the art without departing from the spirit and scope of the invention.

(3) In addition, all ranges disclosed herein are to be understood to encompass any and all subranges subsumed therein. For example, a stated range of 1.0 to 10.0 should be considered to include any and all subranges beginning with a minimum value of 1.0 or more and ending with a maximum value of 10.0 or less, e.g., 1.0 to 5.3, or 4.7 to 10.0, or 3.6 to 7.9.

(4) All ranges disclosed herein are also to be considered to include the end points of the range, unless expressly stated otherwise. For example, a range of between 5 and 10, from 5 to 10, or 5-10 should generally be considered to include the end points 5 and 10.

(5) Further, when the phrase up to is used in connection with an amount or quantity, it is to be understood that the amount is at least a detectable amount or quantity. For example, a material present in an amount up to a specified amount can be present from a detectable amount and up to and including the specified amount.

(6) Some exemplary embodiments will now be further described, including with reference to the figures.

(7) Shape memory gels are among an emerging family of smart materials whose functionality is inducible by a change in thermodynamic state that results in altered physicochemical properties such as appearance, size, shape, flexibility, phase, chemistry, optoelectronic activity or other measurable attribute. The change in thermodynamic state (e.g., energy, entropy, mass, chemical composition, fugacity, specific volume, pressure, temperature) may be induced by one or more of a variety of means (e.g., mechanical, thermal, physicochemical, electromagnetic). Commonly used triggers are temperature, pH, pressure, light, or electrochemical stimuli. Poly(N-isopropylacrylamide), or PNIPAm, a crosslinked polymer hydrogel that changes phase when heated above thirty-two degrees Celsius, transitioning from a swollen hydrated state to a shrunken (up to ninety percent) dehydrated state, is an illustrative example. Applications considered for shape memory gels include switching, actuation, logic-gate operations, functional surfaces, sensing, microfluidic circuits, separations, and biomedical uses such as controlled drug release, engineered tissues or scaffolds, and imaging. However, utility of shape memory gel systems considered to date has been limited by the functionality, scale and interactivity of the gel, its supporting architecture, and corresponding trigger.

(8) This disclosure describes integrating nanoantenna with tunable electromagnetic activity at subwavelength scales into gels in an architecture that supports collection and concentration of targeted microbe(s) via smart cycling of fluid intake, microbe retention, and fluid output. Retained microbe(s) may be analyzed in situ or upon discharge into a carrier fluid.

(9) Nanoantennas are designed to have tunable electromagnetic activity at subwavelength scales in the gel, its constituent fluid and analyte(s). In some cases, computer simulation of the nanoantenna-gel-fluid composite in an externally applied electromagnetic field may be used to select a specific nanoantenna structure. Such simulation tools are described, for example, in G. T. Forcherio, P. Blake, M. Seeram, D. DeJamette, D. K. Roper, Coupled dipole plasmonics of nanoantennas in discontinuous, complex dielectric environments, Journal of Quantitative Spectroscopy & Radiative Transfer (2015), 166, 93-101; D. DeJarnette, P. Blake, G. T. Forcherio, D. K. Roper, Far-field Fano resonance in nanoring lattices modeled from extracted, point dipole polarizability, Journal of Applied Physics (2014), 115, 024306. The suite of simulation tools, candidate architectures, and nanoantenna-polymer composites developed by the inventor has demonstrated the ability to trigger a measurable change in thermodynamic state by an external field that results in tunable polymer expansion, fluid intake, fluid output and pathogen retention across multiple cycles.

(10) Devices and methods described herein provide measurable enhancements in electromagnetic activity, fluid dynamics, and microbe accumulation relative to alternative approaches. Again not intending to be bound by theory, it is believed that enhancements accrue from one or more of the subwavelength scale of tunable electromagnetic activity, the composition and geometry of the nanoantenna, polymer and composite, and novel transport modes and sorption chemistries.

(11) Nanoantennas described herein enable local tunability of shape memory gel at nanometer scales. This supports precise spatiotemporal control of local state (e.g., density) to achieve dynamics that are not possible with current triggers which effect state changes at microscales or greater. A novel spatiotemporal dynamic to support microbe collection and enrichment identified in this disclosure is nanoantenna-enabled peristalsis. Peristalsis is a biological dynamic in which soft material is alternately constricted and relaxed to squeeze fluid through a channel. The peristaltic wavelike pulse provides smooth, localized, energy-efficient nearly unidirectional flow that can accommodate a high percentage of solids. It obviates the need for electrical contacts or mechanical parts that form a basis for conventional pump mechanisms. It minimizes shear and eliminates cavitation, both of which damage biological entities.

(12) In the present implementation, biomimetic peristalsis is effected by the geometry and composition of the nanoantenna-shape memory gel composite and its surrounding architecture as well as the energy dynamics of electromagnetic induction.

(13) Preferential retention of the microbe analyte(s) in the disclosed smart material system results from engineered transport of analyte to solid-fluid interfaces at which a sorptive interaction may occur. Examples of transport include bulk convection, diffusion, eddy flow, and dispersion. Examples of sorptive interactions include electrostatic, ionic, biospecific, hydrophilic, hydrophobic, and mixed mode. Effectiveness of transport and sorptive modes is highly dependent on the characteristics of the analyte (e.g., geometry, physicochemistry, composition) and the carrier fluid and matrix (e.g., physicochemical properties and composition of fluid, solid, and fluid-solid interfaces.) Novel transport and sorptive interaction chemistries and modes are described that facilitate preferential retention of targeted microbe analyte(s). Such transport and sorptive interaction chemistries and modes, such as those described in D. K Roper, S. Nakra, Adenovirus type 5 intrinsic adsorption rates measured by surface plasmon resonance, Analytical Biochemistry (2006), 348, 75-83, can be used in devices and methods described herein.

(14) FIG. 1 illustrates an electromagnetically nanotunable shape memory gel system to collect microbes. As illustrated in FIG. 1(a), microbes (dark dots) are dispersed in a fluid adjacent to an architecture or container (cylinder) with shape memory gel (illustrated with cross-hatch) and uninduced nanoantenna (dark dots). In FIG. 1(b), an electromagnetic trigger induces (e.g., heats) nanoantenna which are concentrated at the gel periphery. In FIG. 1(c), nanoantenna induction densifies the shape memory gel in the peripheral region (darker cross-hatch), preventing backflow. In FIGS. 1(d) and 1(d), continued induction synergistically densifies the gel body, outputting microbe-free fluid above (at the output side of the gel) and inputting microbe-containing fluid below (at the intake side of the gel). In FIG. 1(f), the trigger is halted to relax the gel, retaining microbe at fluid-gel interface via inputting fluid. Then the cycle repeats to enrich microbe content. Enriched microbe is detected in situ or subsequent to discharge of retained microbes in carrier fluid.

(15) Various embodiments of the invention have been described in fulfillment of the various objects of the invention. It should be recognized that these embodiments are merely illustrative of the principles of the present invention. Numerous modifications and adaptations thereof will be readily apparent to those skilled in the art without departing from the spirit and scope of the invention.