This invention relates to apparatus, systems and methods for virus detection. In particular, but not exclusively, embodiments of this invention relate to uses of nanotechnology and radio frequency techniques in identifying a type of virus.
It is widely known that many diseases are caused by viruses. It is therefore important to be able to detect viruses and identify a detected virus to be a particular type of virus as quickly as possible, since it could enable diagnosis at the earliest stages of replication within the host's system, and allow speedy medical decision-making. Moreover, accurate quantification of viruses is very essential for the development of their corresponding vaccines and it is desirable to be able to distinguish between different kinds of viruses presented in a sample.
Many studies are being conducted on developing sensing mechanisms that help speed up virus detection and identification. Most of the existing virus screening and quantifying techniques suffer from limitations, such as the need for extensive sample preparation and steps including viral isolation, extraction, and purification, or from the limitations that they are very costly and time consuming to carry out.
A first aspect of the present invention provides a method, comprising: obtaining a radio frequency response of a lab-on-chip based resonator with virus deposited within a recess of the resonator, determining at least one parameter of the radio frequency response, and identifying a type of the virus or a group to which the virus belongs based on the at least one parameter.
In one embodiment, said at least one parameter is an amplitude or a change of amplitude at a resonance frequency of the resonator with the virus deposited therein.
In one embodiment, the method further comprises measuring said at least one parameter of a radio frequency response when a different types of virus is deposited within the resonator, composing a lookup table containing at least said two types of viruses and their respective frequency response measurements.
In one embodiment, the lab-on-chip based resonator comprises nanotubes, and said depositing virus within the recess of the resonator comprises depositing virus between the gaps of the nanotubes.
In one embodiment, the virus is mixed with functionalized nanoparticles when being deposited within a recess of the resonator.
In one embodiment, the nanoparticles are antibodies and/or quantum dots.
In one embodiment, the said obtaining a radio frequency response of the resonator is performed by a Vector Network Analyser (VNA), which is configured to collect a set of scattering parameter measurements to determine the resonance frequency and a signal amplitude at the resonance frequency.
In one embodiment, said at least one parameter comprises at least one of: a resonance frequency, a change in resonance frequency, a phase at a particular frequency, and a phase shift at a particular frequency of the frequency response.
In one embodiment, said obtaining a radio frequency response is performed at a first temperature, and said determining determines said at least one parameter of the radio frequency response obtained at the first temperature, wherein the method further comprises obtaining, at a second temperature, a radio frequency response of the resonator with the virus deposited within the recess of the resonator, determining a second parameter of the radio frequency response obtained at the second temperature, and wherein said identifying a type of the virus or a group to which the virus belongs is performed based on a comparison between said first parameter and said second parameter.
In one embodiment, said the first temperature is 37° C., and the second temperature is 47° C.
In one embodiment, the method comprises identifying a type of the virus to be HIV if the first parameter and the second parameter are substantially identical, wherein the first parameter and the second parameter are both a magnitude of the frequency response at the resonance frequency.
In one embodiment, said determining a signal amplitude at a resonant frequency of the resonator at the first and the second temperatures is performed by a Vector Network Analyser, which is configured to collect a set of scattering parameter measurements to determine the resonant frequency and the signal amplitude.
A second aspect of the present invention provides an apparatus or a system, comprising: a device for obtaining a radio frequency response of a lab-on-chip based resonator with virus deposited within a recess of the resonator, a device for determining at least one parameter of the radio frequency response, at least one processor and at least one memory, causing the apparatus or the system to identify a type of the virus or a group to which the virus belongs based on said at least one parameter of the radio frequency response.
In one embodiment, said device for determining at least one parameter is configured to determine a magnitude or a change of magnitude at a resonance frequency of the resonator with the virus deposited therein.
In one embodiment, said device for obtaining a radio frequency response of the resonator is a Vector Network Analyser (VNA).
In one embodiment, wherein said device for obtaining a radio frequency response is configured to obtain a radio frequency response at both a first temperature and a second temperature, and wherein said device for determining at least one parameter is configured to determine a first parameter of the radio frequency response obtained at the first temperature and to determine a second parameter of the radio frequency response obtained at the second temperature, wherein said at least one processor and said at least one memory are configured to cause the apparatus or system to identify a type of the virus or a group to which the virus belongs based on a comparison between said first parameter and said second parameter.
In one embodiment, wherein the first temperature is 37° C., and the second temperature is 47° C.
In one embodiment, the apparatus or system comprises identifying a type of the virus to be HIV if the first parameter and the second parameter are substantially identical.
In one embodiment, said at least one parameter comprises at least one of: a resonance frequency, a change in resonance frequency, a phase at a particular frequency, and a phase shift at a particular frequency of the frequency response.
In one embodiment, said at least one processor and at least one memory are configured to cause the apparatus to identify a type of the virus or a group to which the virus belongs based on said at least one parameter of the radio frequency response and data stored in the memory.
Embodiments of the present invention will now be described by way of example with reference to the accompanying drawings:
Embodiments of this invention provide a method for comprising: obtaining a radio frequency response of a lab-on-chip based resonator with virus deposited within a recess of the resonator, determining at least one parameter of the radio frequency response, and identifying a type of the virus or a group to which the virus belongs based on the at least one parameter.
In the embodiment shown in
The resonator 102 behaves as a band pass filter to RF signals propagating through it and has a certain quality factor (Q factor). When RF signals propagate from input 108 to output 110, the resonator rejects or attenuates RF signals with frequencies not matching its mechanical resonance frequency. Therefore, most or all of these RF signals are reflected back and few of them at or very close to the resonance frequency of resonator 102 are transmitted through the nanotubes array. At a RF signal frequency that matches the mechanical resonance of the resonator 102, a substantial proportion of power is transmitted through although a small proportion of power is still reflected.
The nano-tubes array 112 may be isolated from the substrate by a dielectric layer (not shown in the drawings) in case that the tubes are metallic or made of semiconductor. The nano-tubes array 102 may be functionalized so that it provides an enhanced stickiness to virus and can more easily capture virus. The distances between the nano-tubes are large enough to host nanoparticles between them.
The mechanical resonance frequency of the nano-tubes array 112 and overall frequency performance of the device 102 depends on a number of design parameters: materials, diameter and length of the nano-tubes, distance between the nano-tubes and the properties of the dielectric materials that are used to decorate the array, and also the density of the nano-tubes in the array.
The virions 122 stick onto the nano-particles (or quantum dots) 120 more easily than directly onto nano-tubes. The nano-particles 120 may be coated with special materials to capture the virions 122 and make the virus 122 stick to them.
The resonator 302 has a certain quality factor (Q factor) and behaves like a band pass filter to RF signals propagating through it. When RF signals propagate from input 308 to output 310, the resonator rejects or attenuates RF signals with frequencies not matching its mechanical resonance frequency. Therefore, most or all of these RF signals are reflected back and few of them substantially at and near the resonance frequency are transmitted through the resonator 302. At a frequency that matches the resonance frequency of the resonator 302, a substantial proportion of power is transmitted through although a small proportion of power is still reflected.
The resonance frequency and overall frequency performance of the resonator 302 depends on a number of parameters: dietetic material or other materials that are deposited above the substrate, distance between the input and output, dimensions of the gap, etc.
The nanoparticles are dielectric materials and their insertion will change the effective dielectric constant of the cavity, the air gap capacitance and thus the resonant frequency and frequency response characteristics as a consequence of changing the gap capacitance.
These virus particles were used to monitor the specific radio frequency signatures for these retroviruses. In addition, these viral particles were also used to infect target cells resulting in the transduction of these cells with the marker gene present on the packaged RNA, thus allowing for monitoring the propagation of the transfer vector RNA, which could only take place if the virus particles are efficiently produced. The rationale behind pseudotyping different retroviral particles by a common VSV envelope glycoprotein (Env-gp) is based on the fact that all of these retroviral particles (HIV, FIV, MMTV, and MPMV) will be decorated by the similar Env-gp.
To ensure that equal amounts of viral particles are used for radio frequency signature analysis, each transfection was carried out in the presence of an independent DNA, pGL3 Control vector, expressing the luciferase gene. This allows monitoring the transfection efficiencies in our cell cultures as described previously. The amount of culture supernatant (virus particle) used for radio frequency signature analysis for each retrovirus was determined by following a normalization with the transfection efficiencies using the relative light units/μg of protein (RLU).
In one embodiment, each kind of virus is suspended into Dulbecco's Modified Eagle Medium (DMEM), and each mixture is exposed to a radio frequency signal with a power of 10 dBm and with a sweep from 10 MHz up to 13.6 GHz using the measurements setup which is shown in
In the embodiment shown in
A virus specimen is loaded into a hosting RF coaxial resonator structure. The self-resonance frequency of the coaxial cables is set to be above 30 GHz, and will not affect the measurements in the aforementioned frequency range, namely 10 MHz to 13.6 GHz. The system is calibrated using SLOT transmission line techniques for the network analyzer to ensure that the measurements are representations of the mixture solution, but not anything else. A typical calibration will move the measurement reference planes to the end of the test cables. Therefore, it will exclude the effect of losses and phase shifts that could add noise to the measured signal.
As illustrated in
Initially at 7° C. and as has been discussed, some virions exhibit negative differential DC resistance (MMTV, MPMV and FIV) and other exhibits positive differential DC resistance (HIV). As temperature increases, the liquid sample containing virus becomes less conductive, because the thermal vibrations in the lattice increase which causes more electron scattering and more collisions between electrons take place, slowing down flow of electrons. Consequently the rate of electric energy transfer by heating increases along with the electrical resistance causing the magnitude of the S11 parameter in the S-parameters measured by the VNA to shift up.
In one embodiment, the frequency responses can be used to classify viruses. Viruses are classified based on their morphology, capsid and nucleic acid. Both MMTV and MPMV are categorized as beta retroviruses and this explains their close frequency behaviors. Similarly, FIV and HIV belong to the lentivirus group, and their frequency responses are close to each other. The capsid surrounds the virus and it is composed of a finite number of proteins. The lipid bilayer has an average thickness of about 5 nm, with a typical dielectric constant of 2. The change in S11 parameter (one of the S parameters measured by the VNA) level is due to the associated intrinsic DC differential resistance of the virus itself. The increment in S11 parameter is interpreted as the HIV virus introducing losses which are added to the mixture, thus increasing the effective total DC resistance, causing the level to be shifted up by 0.75 dB. Hence the virus is considered as a lossy material that exhibits certain loss dispersion over frequency. On the other side, the decrement in S11 parameter can be attributed to viruses (MMTV and MPMV) exhibiting negative DC resistance. This will in turn reduce the total effective resistance of the mixture by subtracting the DMEM medium losses, thus causing the level to be shifted downward. Such a strategy streamlined the interpretation of the results in terms of specific radio frequency signatures for these different types of viruses, which could then be attributed solely to the specific nature of respective viral particles not due to the presence of different Env-gp.
As will be understood by a person of ordinary skill, profiles similar to those in
The above demonstrates the use of high frequency measurements at different temperatures for detection of retroviruses and lentiviruses in suspended DMEM based solutions. Among the label-free methods that may be used to directly detect viruses, the method according to embodiments of the present invention provides a combination of advantages, such as high sensitivity, quick response, low cost, high throughput, and ease of use.
In step 901, a virus medium, such as DMEM, is deposited on a lab-on-chip device, such as a device shown in
In step 903, a type of virus is mixed with the virus medium and the mixture is deposited within the lab-on-chip device. In step 904, a RF response is obtained for the lab-on-chip device with the mixture deposited therein at the same temperature, namely 37° C. in this embodiment. Measured parameters of the RF response, including a magnitude of the RF response at the resonance frequency, are recorded.
In step 905, steps 903 and 904 are repeated for different types of viruses at the first temperature, namely 37° C. in this embodiment. An equal amount of virus is used for the frequency response analysis for the different types of viruses.
In step 906, a lookup table is compiled. The table comprises the different types of viruses and their corresponding frequency response properties, including magnitudes (and/or changes in signal magnitudes compared to the medium response) at their resonance frequencies at the first temperature (37° C. in this embodiment). The following shows an example of a format of the lookup table.
In an optional step 907, steps 901-906 are repeated at a second temperature, e.g. 47° C. For each type of virus, the difference of signal magnitudes at the resonance frequency at the first and the second temperatures are calculated and recorded the change in the lookup table.
In step 1001, a specimen, such as a blood sample, is obtained. This may be obtained from a patient. In step 1002, a virus medium, e.g. DMEM or other functionalized nanoparticles, is added to the specimen. The virus medium helps increase sensitivity of the measurements and helps attaching the viral particles to the nanoparticles.
In step 1003, the modified specimen is deposited on a resonator, such as the lab-on-chip device illustrated in
In step 1005, the measurement results are used to determine RF frequency response parameters, such as a frequency shift and magnitude at the resonance frequency. In step 1006, a virus type is determined by checking at least one of the determined parameters against data in a pre-defined lookup table, e.g. a table obtained in step 906. For example, a magnitude at the resonance frequency of the device with virus deposited therein can be checked against the data in column 4 of table 1, and a type of virus can be determined if the magnitude corresponds to the data of any one of HIV, FIV, MMTV and MPMV in column 4 of table 1. This determination may be performed manually or automatically by a computer software program run on a computer.
Step 1007 can be used as an alternative way of identifying a type of virus or an additional step to confirm the virus type determined in step 1006. In step 1007, steps 1004 and 1005 are repeated at a second temperature, e.g. 47° C. The change in signal magnitude at the resonance frequency when the temperature is changed from the first temperature to the second temperature is determined. By checking the change of magnitude at the resonance frequency against data in a pre-defined look-up table, e.g. data in column 4 and/or column 5 of table 1 obtained in step 907, it can be determined whether the virus is HIV, FIV, MMTV or MPMV. This determination may be performed manually or automatically by a computer software program run on a computer.
Methods according to various embodiments of the present invention may be performed by using a Vector Network Analyzer to measure parameters of the frequency responses of a lab-on-chip based resonator with virus deposited within. As set out above, a user may manually check the measured parameters against a pre-defined look-up table compiled according to method illustrated in
The advantages of adopting the RF technology and nano-technologies in virus detection include avoiding the use of biomarker and utilize the change in the frequency response caused by the present of the virus inside a sample, such as human blood. The RF detection based methodology according to various embodiments of the present invention provide following: 1) quick and fast initial screening: the time for determining the presence of virus being less than 1 minute; 2) the possibility of characterizing virus using a living cell rather than the conventional way of using dead cell; 3) quick identification of a type of virus after the initial screening by processing the RF response, extracting certain parameters and comparing with a Lookup table for virus properties using. e.g. a computer based software program; 4) Suitability for Emergency cases: fast and quick check; 5) compact size; and 6) ability to detect a variety of virus.
The present invention is not to be limited in scope by the specific aspects and embodiments described herein. Indeed, various modifications of the invention in addition to those described herein will become apparent to those skilled in the art from the foregoing description and accompanying figures. Such modifications are intended to fall within the scope of the appended claims. Moreover, all aspects and embodiments described herein are considered to be broadly applicable and combinable with any and all other consistent aspects and embodiments, as appropriate.
Number | Date | Country |
---|---|---|
02080361 | Oct 2002 | WO |
2009048695 | Apr 2009 | WO |
Entry |
---|
Patolsky et al. Electrical detection of single viruses. PNAS, 2004, vol. 101, pp. 14017-14022. |
Chen et al. An investigation of the mechanisms of electronic sensing of protein adsorption on carbon nanotube devices. Journal of the American Chemical Society, 2004, vol. 126, pp. 1563-1568. |
Tan et al. Controllable fabrication and electrical performance of single crystalline Cu2O nanowires with high aspect ratios. Nano Letters, 2007, vol. 7, pp. 3723-3728. |
Lieber CM. Integrated nanoscale nanowire correlated electronic nanosensing (INNOCENT), Jun. 20, 2006, 27 pages. |
Elsheakh, D. et al. “Novel rapid detection of different viruses in blood using microimmuno-sensor.” In: 2013 7th European Conference on Antennas and Propagation (EuCAP), Apr. 8-12, 2013, Gothenburg, pp. 1128-1131. IEEE. |
Lonappan, A. “Novel method of detecting H1N1 using microwaves.” Journal of Biomedical Science and Engineering, 2012, vol. 5, pp. 476-479. |
Gupta, A. et al. “Single virus particle mass detection using microresonators with nanoscale thickness.” Applied Physics Letters, 2004, vol. 84, No. 11, pp. 1976-1978. |
Barton, R.A. et al. “Fabrication of a nanomechanical mass sensor containing a nanofluidic channel” Nano Letters, 2010, vol. 10, pp. 2058-2063. |
Cui, Yan et al. “A simple, tunable, and highly sensitive radio-frequency sensor.” Applied Physics Letters, Aug. 8, 2013, vol. 103, pp. 062906-(1-3). |
Al Ahmad, M. et al. “RF Microalgal lipid content characterization.” Scientific Reports, May 29, 2014, vol. 4, pp. 5108-(1-6). |
International Search Report for International Application No. PCT/IB2014/065180 with a mailing date of Mar. 30, 2015. |
Written Opinion of the International Searching Authority for International Application No. PCT/IB2014/065180 with a mailing date of Mar. 30, 2015. |
Number | Date | Country | |
---|---|---|---|
20150104783 A1 | Apr 2015 | US |