1. LSPR based Plasmonic Multi-sensor
for Quantitative Analysis of Ionic
Liquids-water binary mixtures
Simitha S, a Shinto M Francis, b Jesly Jacob*b and Vibin Ipe Thomas*a
a Department of Chemistry, CMS College, Kottayam-686001, Kerala, India
b Department of Physics, Assumption College, Changanacherry, Kottayam-
686101, Kerala, India
2. INTRODUCTION
Plasmonic sensors are devices that are capable of providing quantitative or semiquantitative
analytical information using dependency of surface plasmon resonance on permittivity of
embedded medium come in direct contact.
WHY? Rapid, label-free, real-time Monitoring, High detection Sensitivity And Excellent
Performance
Parameters (FOM,Q-factor, resolution)
HOW?
Biosensors
- Antigen-antibody binding [1] - Cancer diagnostics[3]
- Glucose level monitoring [2] - Hemoglobin-blood group
analysis[4,5]
- Protein interactions
Temperature and concentration analysis[6] etc.
Electromagn
etic wave
Plasmonic materials
(size, shape,
surrounding medium
permittivity)
(1) Chu S, Nakkeeran K, Abobaker AM, et al (2020) A Surface Plasmon Resonance Bio-Sensor based on Dual Core D-Shaped Photonic Crystal Fibre Embedded with Silver Nanowires for Multi-Sensing. IEEE Sens J PP:1–1. https://doi.org/10.110
(2) Rakhshani MR, Tavousi A, Mansouri-Birjandi MA (2018) Design of a plasmonic sensor based on a square array of nanorods and two slot cavities with a high figure of merit for glucose concentration monitoring. Appl Opt 57:7798. https://
(3) Jabin MA, Ahmed K, Rana MJ, et al (2019) Surface Plasmon Resonance Based Titanium Coated Biosensor for Cancer Cell Detection. IEEE Photonics J 11:. https://doi.org/10.1109/JPHOT.2019.2924825
(4) Heidarzadeh H (2020) Analysis and simulation of a plasmonic biosensor for hemoglobin concentration detection using noble metal nano-particles resonances. Opt Commun 459:. https://doi.org/10.1016/j.optcom.2019.124940
(5) Rakhshani MR, Mansouri-Birjandi MA (2018) Engineering Hexagonal Array of Nanoholes for High Sensitivity Biosensor and Application for Human Blood Group Detection. IEEE Trans Nanotechnol 17:475–481. https://doi.org/10.1109/TNA
(6) Akter S, Ahmed K, El-Naggar SA, et al (2020) Highly Sensitive Refractive Index Sensor for Temperature and Salinity Measurement of Seawater. Optik (Stuttg) 216:164901. https://doi.org/https://doi.org/10.1016/j.ijleo.2020.164901
(7) https://nicoyalife.com/nicoya-surface-plasmon-resonance-resources/what-is-spr/lspr-vs-spr-2/
Shift in
λres
APPLICATIONS
Excitation surface
plasmons at the
vicinity of sensor
platform
Representation of resonance shift with
ligand-analyte interaction. Adopted from
[7]
3. OBJECTIVES
Theoretical designing and performance optimization of a cavity based
LSPR structure for
Simultaneous multi-analyte composition analysis
Repeated confirmation of single analyte with added possibility of
optional duel short band electromagnetic wave usage
Performance enhancement via position-wise asymmetry introduction
NOVELTY OF THE WORK
Synchronized multi-parameter analysis
Broad Refractive index (RI) sensing (0.5-
1.8 RIU) across visible-near IR region
Ability of Single/multiple analyte
prediction in single simulation
Compositional study of single/dual ILs-water binary
mixture aiding possible protein denaturation
analysis
Green alternatives to organic solvents
due to
low vapour pressure, Thermal
stability, non flammable, high
ability to dissolve and stabilize
enzymes, protein, DNA and RNA
Possibility of tuning stability,
crystallization and aggregation of protein
via salt composition in hydrated ionic
liquids[8]
Why Ionic Liquid(ILs)-
water binary mixtures?
(8) Kohno, Yuki; Ohno, Hiroyuki (2012). Ionic liquid/water mixtures: from hostility to conciliation. Chemical Communications, 48(57), 7119–
. doi:10.1039/c2cc31638b
4. FEM
Finite Element Method
Solving differential equations, together with boundary
condition, over the domain of complex structures
Governing
Equation: L(φ ) + f =
0
+
Boundary
Conditions: B(φ ) + g
= 0
A set of simultaneous
FEM algebraic
equations
[K]{u} = {F}
FEM
You know all the equations, but you
cannot solve it by hand
Approximate!
Property
(Dielectric Permittivity)
Behaviour
(Electrical Potential)
Action
(Charge)
FEM cuts
a
structur
e into
several
element
s
•Then
reconne
cts
element
s at
“nodes”
•This process
results in a set
of
simultaneous
algebraic
equations
(9) J. N. Reddy, Ph.D. Introduction to the Finite Element Method, Fourth Edition (McGraw-Hill Education: New York, Chicago, San Francisco, Athens, London, Madrid, Mexico City, Milan, New Delhi,
Singapore, Sydney, Toronto, 2019, 2006, 1993, 1984). https://www.accessengineeringlibrary.com/content/book/9781259861901
CH1 CH2
Design of the proposed
structure
5. SENSOR DESIGN
Aspect ratio- a:1.39a,
a=175nm
Cavity size- w
Materials used- Ag, Si
Direction of wave propagation - y
direction
Wavelength range- 1.2 µm to 2.2
µm
Direction of polarization- x
Solved for Scattered Field
Ionic liquid
mole
fraction
( 𝜒1)
n[bmim]
[BF4] +
water
Ionic liquid
mole
fraction
( 𝜒1)
n[omim]
[BF4] +
water
0.0000 1.3335 0.000 1.3335
0.2002 1.3825 0.3005 1.4165
0.4003 1.3980 0.4006 1.4205
0.5999 1.4045 0.6001 1.4265
0.8004 1.4085 0.8004 1.4305
1.0000 1.4150 1.000 1.4325
Values of refractive index, n, of binary
mixtures of [bmim][BF4] + water, with Ionic
Liquid mole fractions, 𝜒1 , at temperatures
293.15 used for computation. Adopted from
[10]
(10) Carissimi, Guzmán; Montalbán, Mercedes G.; Díaz Baños, F. Guillermo; Víllora, Gloria (2019). Density, Refractive Index and
Volumetric Properties of Water–Ionic Liquid Binary Systems with Imidazolium-Based Cations and Tetrafluoroborate, Triflate and
Octylsulfate Anions at <i>T</i> = 293 to 343 K and <i>p</i> = 0.1 MPa. Journal of Chemical &
Engineering Data, (), acs.jced.8b00854–. doi:10.1021/acs.jced.8b00854
Performance Evaluation Parameters
Geometric Parameter
Sensitivity (S)=
∆λ
∆n FOM =
S
FWHM
Qfactor =
λres
FWHM
∆𝜆 = shift in resonance wavelength
∆n = change in refractive index
FWHM = full width at half maximum
6. COMPLETE SYMMETRY IN STRUCTURE
Normalized scattering cross section of designed nano
structure with channel 1 loaded with [bmim][BF4] -water
mixture having refractive index (1.3335 RIU) and
channel 2 varying across n = (1.3825 RIU), (1.3980 RIU),
(1.4045 RIU), (1.4085 RIU) and (1.4150 RIU).
Swapping of RI in the channels
Symmetry in structure
Similar scattering/absorption profile
3 dimensional plot of electric field distribution
across sensor channels for respective resonant
wavelengths
7. POSITION WISE
ASYMMETRY IN STRUCTURE
Normalized scattering cross section while channel 1
and channel 2 loaded with same [bmim][BF4] -water
composition, i.e., χIL =0.4003 before and after
introduction of position-wise asymmetry in
designed structure.
RI of both channel fix to 1.3980 (χIL =0.4003 )
λ res(symm) =1803 nm
symmetri
c
structure
uniform ring
disc
separation in
channels
uniform
ring-disc
coupling
across
sensor
channels
single
resonanc
e
position
λ res (asymm) = 1835nm and 1882 nm
multiple
resonance
position
different
ring disc
separation
in channels
asymmetric
channels
non-uniform
ring-disc
coupling
across
sensor
channels Continue..
10. CONCLUSION
Symmetric plasmonic sensor platform capable of predicting single/multiple
analytes in a fast, label free way
Sensor performance enhancement + multi-functionality is achieved via structural
asymmetry tuning
Performance optimized sensor exhibits multi-confirmation analysis of analytes
with optional short band EM wave usage
Possibility of Synchronous Multiple analyte RI and/or composition detection.
Compositional study of ILs-water binary mixtures aids effective protein
denaturation analysis
Spectral shift with wide range permittivity (RI 1- 1.8 RIU) of embedded medium
paves the possible applications in various chemical and biosensors
Polarization depended behaviour of array of the asymmetric system further
improves the performance versatility with added possibility of multi-purpose
multi-sensor.
![INTRODUCTION
Plasmonic sensors are devices that are capable of providing quantitative or semiquantitative
analytical information using dependency of surface plasmon resonance on permittivity of
embedded medium come in direct contact.
WHY? Rapid, label-free, real-time Monitoring, High detection Sensitivity And Excellent
Performance
Parameters (FOM,Q-factor, resolution)
HOW?
Biosensors
- Antigen-antibody binding [1] - Cancer diagnostics[3]
- Glucose level monitoring [2] - Hemoglobin-blood group
analysis[4,5]
- Protein interactions
Temperature and concentration analysis[6] etc.
Electromagn
etic wave
Plasmonic materials
(size, shape,
surrounding medium
permittivity)
(1) Chu S, Nakkeeran K, Abobaker AM, et al (2020) A Surface Plasmon Resonance Bio-Sensor based on Dual Core D-Shaped Photonic Crystal Fibre Embedded with Silver Nanowires for Multi-Sensing. IEEE Sens J PP:1–1. https://doi.org/10.110
(2) Rakhshani MR, Tavousi A, Mansouri-Birjandi MA (2018) Design of a plasmonic sensor based on a square array of nanorods and two slot cavities with a high figure of merit for glucose concentration monitoring. Appl Opt 57:7798. https://
(3) Jabin MA, Ahmed K, Rana MJ, et al (2019) Surface Plasmon Resonance Based Titanium Coated Biosensor for Cancer Cell Detection. IEEE Photonics J 11:. https://doi.org/10.1109/JPHOT.2019.2924825
(4) Heidarzadeh H (2020) Analysis and simulation of a plasmonic biosensor for hemoglobin concentration detection using noble metal nano-particles resonances. Opt Commun 459:. https://doi.org/10.1016/j.optcom.2019.124940
(5) Rakhshani MR, Mansouri-Birjandi MA (2018) Engineering Hexagonal Array of Nanoholes for High Sensitivity Biosensor and Application for Human Blood Group Detection. IEEE Trans Nanotechnol 17:475–481. https://doi.org/10.1109/TNA
(6) Akter S, Ahmed K, El-Naggar SA, et al (2020) Highly Sensitive Refractive Index Sensor for Temperature and Salinity Measurement of Seawater. Optik (Stuttg) 216:164901. https://doi.org/https://doi.org/10.1016/j.ijleo.2020.164901
(7) https://nicoyalife.com/nicoya-surface-plasmon-resonance-resources/what-is-spr/lspr-vs-spr-2/
Shift in
λres
APPLICATIONS
Excitation surface
plasmons at the
vicinity of sensor
platform
Representation of resonance shift with
ligand-analyte interaction. Adopted from
[7]](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)