Phasmon biosensor, device and application method based on polarization state modulation
Technical field
The present invention relates to phasmon biosensor, device and application methods, specially based on polarization state modulation etc.
From excimer biosensor, device and application method.
Background technique
In recent years, local surface plasmon resonance (LSPR) bio-sensing based on metal Nano structure obtains quickly
Development, local surface plasmon resonance bio-sensing is a kind of optical sensing technology, using in light and metal Nano structure from
The surface phasmon as caused by electronics coupled detects the micro- of metallic nanostructured surface as optical probe in high sensitivity
The variation of little refraction rate.By sensor chip, real-time, original position and dynamic measure various biomolecule such as polypeptide, protein, and
Virus, bacterium, cell, the interaction process between small molecule compound.In drug screening, clinical diagnosis, food and environment
Application in the fields such as monitoring and membrane biology is growing, and is expected to become a kind of important in life science and pharmacy research
Biological detection tool.The sensing principle of LSPR is through formant on monitoring LSPR Spectral Extinction, reflectance spectrum or transmission spectrum
Wavelength change determines the changes delta of structural outer environment (corresponding specific refractive index)n, the corresponding wave in the same terms low-resonance peak
Long variation is bigger, and the sensitivities of the micro-nano structure are better.Refractive index sensitivitySIt is exactly to change size for quantitatively characterizing formant
Physical quantity, i.e.,S=Δλ/Δn, wherein ΔλIt is the variable quantity of resonance peak.Influence another amount of sensor senses characteristic
It is the width of resonance spectrum, the spectrum the fine more is conducive to differentiate more small peak position offset, in order to express resonance spectral width pair
The influence of transducer sensitivity introduces quality factor (figure of merit, FoM) and is used as evaluation reference index.FoM can table
It is shown as refractive index sensitivitySWith the ratio of resonance spectrum halfwidth FWHM, that is, have FoM=S/FWHM。
Compared with other bio-sensing methods, local surface plasmon resonance biosensor has better characteristics.
In terms of being in particular in following three, first, local surface plasmon resonance is very quick for the minor change of ambient refractive index
Sense;Second, simple with the metal surface treatment process of liquid medium interaction, any substance for being attached to metal surface can all draw
Very strong signal intensity is played, so that the device is very suitable for measuring the combination of the compatibility between any target biological molecules sample
Reaction;Third, local surface plasmon resonance belong to the field that dies of declining, with the small advantage of ambient noise.
In existing research, carrying out biomolecule detection has following several method:
Using electric chemical formula biosensor technique, it is usually using some enzyme elements as probe.But this transducing signal is low,
Sensitivity is not high, and complicated for operation, therefore limits the universal of the technology.
There is research to be marked with fluorescent molecule to be detected, improves the sensitivity and accuracy of detection, but this technology exists
Need to carry out external label when detecting macromolecular, step is complicated cumbersome and is easily destroyed molecular structure, there are detection sensitivity by
The disadvantages of limit, structural instability.
Biomolecule is detected using local surface plasmon resonance technology, with traditional electric chemical formula, fluorescence
Method etc. is compared, it has the characteristics that real-time detection, sample is few, local area environment measuring can be achieved without marking, consuming.However due to office
Field surface phasmon structure causes local surface plasmon resonance spectral line width there are biggish radiation and radiationless loss
It is very big, so that generally not high (FoM < 50) based on local surface plasmon resonance biosensor quality factor FoM.Non- patent
Document Nicolo Maccaferri, Keith E. Gregorczyk1, Thales V.A.G. de Oliveira1 et
Al.Nature Communications, 2015,6:6150 DOI:10.1038ncomms7150 proposes newest detection
Technology is to carry out biomolecule detection to the regulation of light field polarization state using magnetic Nano antenna.This technology largely mentions
The high quality factor FoM(FoM ≈ 150 of sensor).But there is also some shortcoming and defect, for example, nano-antenna must be
Ferrimagnet, material property is unstable, is easily oxidized in air;Compared with noble metal, absorption of the ferrimagnet to light
Loss is bigger, limits the enhancing of local fields, is unfavorable for refractive index sensitivitySRaising;This method is imitated based on magneto-optic simultaneously
The modulation that should realize light field polarization state needs additional very big magnetic field, and sensing device is more complicated, these disadvantages are to a certain extent
Limit its application in terms of sensing.Therefore, it is raw to study the simple phasmon of a kind of stable structure, high sensitivity, device
Object sensor and application method be very it is necessary to.
Summary of the invention
It is unstable that the present invention solves the existing magnetic Nano antenna biosensor material property based on the modulation of light field polarization state
It is fixed, be easily oxidized, influenced by external magnetic field, the problem of sensing device complexity, provide a kind of grade modulated based on polarization state from
Excimer biosensor, device and application method.
The present invention is achieved by the following technical solutions: the phasmon biosensor based on polarization state modulation, packet
Substrate of glass is included, the size being made of noble metal nano particles of the same race is collectively aligned in the substrate of glass in nanoscale two dimension
The symmetry of structure, the two-dimensional structure belongs to CSOr C2VOr C∞VOr C2hOr D2hOr D∞hOne of point group.Such as branch shape
Structure belongs to CSPoint group, two branch sizes are not equal to 0 ° in nanoscale, angle between the two;L-shaped structure belongs to C2VPoint group,
Two-arm size is in nanoscale;Match rod-like structure belongs to C∞VPoint group, one end head are nanoscale disk, and the other end is along disk
The nanoscale straight-arm extended radially outward;X-shaped structure belongs to C2hPoint group, two nanoscale straight-arm angles are not equal to 0 °;Dumbbell shape structure
Belong to D2hPoint group, middle part are nanoscale straight-arm, and straight-arm both ends are separately connected the V-shaped nanoscale folding being made of two inclined arms
The V-shaped nanoscale folding arm of arm, the both ends is symmetrical along the length of middle part straight-arm, width direction perpendicular bisector;Nanoscale straight-arm knot
Structure belongs to D∞hPoint group.When linearly polarized light vertical irradiation medium, a reference axis is selected, can be always decomposed into incident electric fields
X, the component of y both direction, as shown in Fig. 1, selected axis make angle of polarization θ=45o, at this time both direction component amplitude phase
Deng, phase difference 0, phase difference is π when θ=135o: when by sensing chip, so that above-mentioned two direction electric field component amplitude ratio
Example, phase difference change, i.e. the modulation of realization light field polarization state.It is still linear polarization if only amplitude scale changes, but polarizes
Angle changes;When phase difference is not 0 or π, linear polarization variation is elliptical polarization.Light field polarization state is realized using metal nanoparticle
It is similar with incident ray polarized light when modulation, identical reference axis can be also selected, regards metal nanoparticle as the direction x, y two
Point, when two parts are symmetrically identical, amplitude and the phase variation having the same of the electric field component of x, y both direction, then
Output light field polarization state is constant;When structure two parts difference, vibration of the metal nanoparticle to the electric field component of x, y both direction
Width and phase-modulation effect are different, then output light field polarization state changes.D mentioned above∞h, C∞v, Cs, C2v, C2h, D2hPoint
The common trait of group structure is: without high secondary axes (i.e. symmetry axis of the axis time higher than 2 times), this feature to have above-mentioned symmetrical
Property structure can realize polarization state modulate, i.e., structure decomposes in a coordinate system after the direction x and y asymmetry.In addition, to realize that polarization is adjusted
System, incident light polarization direction should deviation structure symmetry axis or the plane of symmetry, this common sense being known to the skilled person.On
The size of single nanoparticle is stated tens between thousands of nanometers, and the two-dimensional structure size being made of nanoparticle arrangement is then
At several microns between several hundred microns, specific size should meet requirement of the ellipsometer to signal strength detection, and nano particle
Arrangement can be period or aperiodic arrangement, but each nano particle should ensure that identical orientation (being collectively aligned), nanometer
Intergranular is every being then maintained at tens between thousands of nanometers, and to realize the modulation to light field polarization state, this is those skilled in the art
Known common sense, details are not described herein.
Based on the phasmon biosensor arrangement of polarization state modulation, including wide spectrum light source, the hair of the wide spectrum light source
It penetrates end and is connected with polarizing film and y-type optical fiber in turn, the transmitting terminal of divergent ends one end connection wide spectrum light source of the y-type optical fiber divides
The other end of fork is connected with ellipsometer, and the common end of the y-type optical fiber is connected with fiber coupler, one end of fiber coupler
It is connected with the common end of y-type optical fiber, the other end of fiber coupler is connected with fibre-optical probe;Biosensor arrangement further includes sample
Product pond, the sample bottom of pond portion are equipped with the phasmon biosensor modulated based on polarization state.Wide spectrum light source provides for test
The steady and continuous light of fixed wave length range.The non-polarized light of light source is converted linearly polarized light by polarizing film, and polarization direction is deviateed
The symmetry axis or the plane of symmetry of sensor two-dimensional structure.Y-type optical fiber connects wide spectrum light source, ellipsometer and fiber coupler.Optical fiber coupling
Optical signal is allocated or is combined in y-type optical fiber by clutch.Fibre-optical probe sends and receives optical signal.Sample cell is for holding
Sample solution to be tested.The free electron in noble metal nano structure on local surface phasmon biosensor is in light
Under the action of the excitation light field that fibre probe issues, collective oscillation is generated, to excite local surface phasmon, and electricity occurs
Lotus transfer effect generates the transmission and reflected light of elliptical polarization (setting ellipticity as ε) so that light field polarization state changes,
Modulation of the middle ellipticity ε by local surface plasmon resonance (i.e. excitation wavelength).
Based on the phasmon biosensor arrangement application method of polarization state modulation, including following operating procedure:
A, wide spectrum light source is opened, fibre-optical probe is fixed on above sample cell, the light for enabling fibre-optical probe issue vertically shines
Penetrate the local surface phasmon biosensor surface in sample bottom of pond portion;
B, the light that fibre-optical probe issues receives again after the reflection of phasmon biosensor, and conducts to ellipsometer,
Ellipse inclined rate ε is obtained after analyzing by ellipsometer spectrum with the spectrum of excitation optical field wavelength variation, further calculating can obtain
The spectrum that ellipticity 1/ ε of inverse changes with excitation optical field wavelength;
C, testing sample solution is introduced in sample cell, repeats step b, is obtained light source and is irradiated to after solution to be measured refraction
Corresponding 1/ ε ' of polarization state spectrum that phasmon biosensor surface generates;
D, the offset for calculating both front and back polarization state spectrum 1/ ε and 1/ ε ' peak position, can be calculated by the size of offset
Out introduce testing sample solution caused by variations in refractive index, and then can analyze obtain introduce testing sample solution characteristic (such as to
Concentration, biomolecule type of sample solution etc.).
Wide spectrum light source issues continuous light, is converted into linearly polarized light after polarizing film, linearly polarized light by y-type optical fiber one end into
Enter optical fiber, after fiber coupler, fibre-optical probe vertical irradiation in surface phasmon biosensor surface (hereinafter referred to as
Sensor).The free electron in noble metal nano structure on sensor under the action of the excitation light field that fibre-optical probe issues,
Collective oscillation is generated, to excite local surface phasmon, and charge transfer effect occurs, so that light field polarization state occurs
Change, the reflection for generating elliptical polarization and transmitted light are (to receive transmitted light, then in sample cell bottom surface and top fibre-optical probe phase
One piece of fibre-optical probe is also fixed to position).Ellipsometer can carry out spectrum analysis processing to the reflection of elliptical polarization or transmitted light, obtain
To ellipticity with the spectrum of excitation optical field wavelength variation, ellipticity 1/ ε of inverse can be obtained by further calculating becomes with excitation optical field wavelength
The spectrum of change.After introducing testing sample solution, the refractive index of the noble metal nano structure periphery environment on sensor will become
Change, to influence modulation of the sensor to light field polarization state, and then changes reflection or transmitted light polarization state spectrum, thus obtain 1/
ε ' spectrum.Ideally, 1/ ε of ellipticity inverse will tend to be infinitely great at resonance peak;Under actual conditions, due to ellipsometer
The presence of resolution ratio and other experimental errors, 1/ ε of ellipticity inverse is a limited value at resonance peak, but existing experiment
The result shows that it still can be greater than 100000.The change of the ε ≈ 0 near resonance peak, ellipticity ε very little will also result in ellipse
The 1/ ε very big variation of rate inverse, thus the measurement based on 1/ ε of ellipticity inverse can obtain very delicate spectrum (halfwidth <
1nm).Therefore, when introducing testing sample solution, i.e. external environment refraction index changing, even the formant less than 1nm deviates,
It easily can also be resolved out.So this method largely improves the sensor mass factor (FoM >
1500), to substantially increase the sensitivity of sensor.
Compared with the prior art, the present invention has the following advantages: 1, with non-patent literature in based on magnetic metal nanometer plate
Method for sensing (realizing that polarization state is modulated using magneto-optic effect) is compared, and is imitated using electric charge transfer caused by noble metal nano structure
It answers, the modulation to transmission or reflection polarization state can be directly realized by, so there is no need to externally-applied magnetic field, whole device structure is simpler
It is single, and externally-applied magnetic field is avoided on the possible influence of sample to be tested;2, compared with the sensor based on magnetic metal material, your gold
Belonging to material has smaller absorption loss, therefore noble metal nano body structure surface can form bigger local fields increasing on sensor
By force, it is very beneficial for the absorption of sample to be tested (such as biomolecule), to improve sensing sensitivity;3, and based on dielectric or magnetic
Property metal material sensor compare, sensor uses precious metal material (as gold) in the present invention, and chemical property is more stable,
It is not easy to be oxidized, therefore sensing chip may be reused, while noble metal nano structure is directly contacted with sample to be tested, is conducive to
The raising of sensing sensitivity;4, compared with tradition is based on the sensor of intensity spectral line measurement (spectrum widening dozens to a few hundred nanometers,
50) sense quality factor FoM is generally less than, the present invention is based on the measurement of the polarization state of light, spectrum widening is smaller than 1nm, senses matter
1500 can be greater than by measuring factor FoM, substantially increase sensing sensitivity.
Detailed description of the invention
Fig. 1 is incident ray polarized light decomposition diagram;
Fig. 2 is detection polarization state schematic diagram;One incident ray of figure shows Fig. 2 shape after phasmon biosensor
State;(incident ray is known as detecting light after sensor reflects or reflects by the light that probe receives)
Fig. 3 is one structural schematic diagram of embodiment;
Fig. 4 is two structural schematic diagram of embodiment;
Fig. 5 is three structural schematic diagram of embodiment;
Fig. 6 is example IV structural schematic diagram;
Fig. 7 is five structural schematic diagram of embodiment;
Fig. 8 is six structural schematic diagram of embodiment;
Fig. 9 is seven structural schematic diagram of embodiment;
Figure 10 is surface phasmon biosensor arrangement structural schematic diagram.
1- wide spectrum light source in figure, 2- polarizing film, 3-Y type optical fiber, 4- ellipsometer, 5- fiber coupler, 6- fibre-optical probe, 7-
Sample cell, 8- phasmon biosensor, 9- substrate of glass, 10- noble metal nano particles.
Specific embodiment
Based on the phasmon biosensor arrangement of polarization state modulation, including wide spectrum light source 1, the wide spectrum light source 1
Transmitting terminal is sequentially connected by polarizing film 2 and y-type optical fiber 3, the hair of divergent ends one end connection wide spectrum light source 1 of the y-type optical fiber 3
End is penetrated, the other end of divergent ends is connected with ellipsometer 4, and the common end of the y-type optical fiber 3 is connected with fiber coupler 5, optical fiber coupling
One end of clutch 5 and the common end of y-type optical fiber 3 connect, and the other end of fiber coupler 5 is connected with fibre-optical probe 6;Bio-sensing
Device device further includes sample cell 7, and 7 bottom of sample cell is equipped with the phasmon biosensor 8 modulated based on polarization state.
When it is implemented, the wide spectrum light source 1 is halogen lamp or Light-emitting diode LED.
Embodiment one: the phasmon biosensor based on polarization state modulation, including substrate of glass, the substrate of glass
On be collectively aligned gold nano grain composition size in nanoscale two-dimensional structure, the symmetry of the two-dimensional structure belongs to CS
Point group, specific size be the long 150nm of horizontal branch, tilt the long 120nm of branch, 30 ° of the two angle, each branch width 40nm,
Thickness 30nm, each interparticle spacings 250nm.
Embodiment two: the phasmon biosensor based on polarization state modulation, including substrate of glass, the substrate of glass
On be collectively aligned silver nano-grain composition size in nanoscale two-dimensional structure, the symmetry of the two-dimensional structure belongs to C2V
Point group, specific size are brachium 150nm, width 40nm, thickness 30nm, each interparticle spacings 250nm.
Embodiment three: the phasmon biosensor based on polarization state modulation, including substrate of glass, the substrate of glass
On be collectively aligned Pt nanoparticle composition size in nanoscale two-dimensional structure, the symmetry of the two-dimensional structure belongs to
C∞VPoint group, specific size are the long 150nm of straight-arm, disk diameter 60nm, thickness 40nm, each interparticle spacings 250nm.
Example IV: the phasmon biosensor based on polarization state modulation, including substrate of glass, the substrate of glass
On be collectively aligned gold nano grain composition size in nanoscale two-dimensional structure, the symmetry of the two-dimensional structure belongs to C2h
Point group, specific size are wherein brachium 120nm, another long 200nm of straight-arm always, 60 ° of angle, width 40nm, thickness 30nm,
Each interparticle spacings 150nm.
Embodiment five: the phasmon biosensor based on polarization state modulation, including substrate of glass, the substrate of glass
On be collectively aligned silver nano-grain composition size in nanoscale two-dimensional structure, the symmetry of the two-dimensional structure belongs to D2h
Point group, specific size are the long 50nm of middle part straight-arm, and both ends tilt brachium 100nm, width 40nm, thickness 30nm, between each particle
It is spaced 150nm.
Embodiment six: the phasmon biosensor based on polarization state modulation, including substrate of glass, the substrate of glass
On be collectively aligned Pt nanoparticle composition size in nanoscale two-dimensional structure, the symmetry of the two-dimensional structure belongs to
D∞hPoint group, specific size are the long 300nm of straight-arm, width 40nm, thickness 30nm, each interparticle spacings 150nm.
Embodiment seven: the phasmon biosensor based on polarization state modulation, including substrate of glass, the substrate of glass
On be collectively aligned gold nano grain composition size in nanoscale two-dimensional structure, the symmetry of the two-dimensional structure belongs to
D∞hPoint group, the nano particle two-dimensional structure are dimer, and the symmetry of the dimer still belongs to D∞hPoint group, it is specific
Having a size of the long 300nm of single straight-arm, width 40nm, thickness 30nm, notch 20nm, each interparticle spacings 150nm between two straight-arms.Two
Dimeric structure can improve the sensitivity of sensor using the effect of surface phasmon coupling local area field enhancing.