Presentation by Bello Hamza Abdullahi. Table of contents Introduction. Suspended microchannel...
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EEE529 MICROSYSTEM SUSPENDED MICROCHANNEL RESONATOR Presentation by Bello Hamza Abdullahi
Presentation by Bello Hamza Abdullahi. Table of contents Introduction. Suspended microchannel Resonator(SMR). Beam Model. SMR With Integrated Piezoresistive
Table of contents Introduction. Suspended microchannel
Resonator(SMR). Beam Model. SMR With Integrated Piezoresistive
Readout. Fabrication Of SMR. Performance Factors. Advantages.
Applications.
Slide 3
Introduction There are three commonly used devices in detecting
bio-molecules, these are; microcantilever-based biosensor. Surface
Plasmon Resonance (SPR) sensor and, Quartz Crystal Microbalance
(QCM) sensor. For micro-cantilever-based biosensors, there are two
working principles developed for the biodetection, namely, the
static mode and the dynamic mode.
Slide 4
Slide 5
Suspended Micro-channel Resonator(SMR) SMR is a biosensor that
falls under micro-cantilever based dynamic mode biosensor. This is
a hollow micro-cantilever that vibrate with a certain resonance
frequency. It resonates at a frequency proportional to its total
mass. This works base on the reduction of resonance frequency of
the hollow microcantilever induced by molecular adhesion, if an
analyte flow through the hollow cantilever.
Slide 6
Slide 7
SMR Since SMR is a cantilever it should have the following;
Since the tip end, is freely suspended it can easily vibrate. There
is low or even no effect of vibration at the fixed end. It
resonates at a frequency proportional to its total mass. Therefore
change in mass affect the resonance frequency. The vibration
intensity reduced as you move from the tip end to the fixed
end.
Slide 8
Slide 9
SMR Particles are weighed in real-time with the suspended
micro-channel resonator (SMR) as they flow through a hollow
cantilever. The micro-channel resonant frequency is determined by
the difference in mass of the particle with respect to that of the
displaced fluid. Thus, the particle's density is determined by
measuring its mass in two fluids of different densities.
Slide 10
Beam Model Of SMR As the fluid flows inside the SMR, we could
study how the relevant properties of the fluid affect its resonant
frequency. Derivation of the dynamic theory of the SMR is mainly
separated into two parts, namely: A structure element and, fluid
element.
Slide 11
Beam model of SMR The structural parts depends on the following
parameters; The cross sectional area of the internal rectangle
tube,(A); young modulus,(E); Moment of inertia, (I) Mass per unit
length of the empty rectangle tube,(m) Longitudinal tension applied
on the structure element,(T)
Slide 12
Beam Model of SMR Transverse shear force applied on the
structure element(Q), Bending moment applied on the structure
element(M), shear stress on the internal surface of the rectangle
tube(q), Inner perimeter of the rectangle tube(S),
Slide 13
Beam Model of SMR For the fluids, depends on: The flow
pressure(P), Density(), viscosity(), Shear stress induced by the
viscosity() and, The transverse force per unit length between tube
wall and fluid(F). Following the DAlemberts principle of dynamic
equilibrium, the equation of motion for the SMR is given in the
next slide.
Slide 14
A Sketch of the 1-D beam model. where v(x, t) is the deflection
of the beam. U is the average flow velocity. L,B and H is the
length, width, and height of the beam, respectively.
Slide 15
Beam Model of SMR
Slide 16
The solution of the above equation can be represented by Then
Eq. (2) can be rewritten as
Slide 17
Beam Model of SMR where n`s are the normal modes of the beam
without viscosity (i.e. = 0), n`s are the expansion coefficients,
and is the dimensionless circular frequency, where f is the
frequency. By orthogonality of n( ), one can obtain the following
equation from (4) and (5): See next slide.
Slide 18
Beam Model of SMR where the coefficient matrices [A] to [E] are
defined by
Slide 19
Beam Model of SMR To obtain nontrivial solutions, the
determinant of coefficient matrix must be zero, i.e., From the
above equation, one can determine the resonant frequencies of the
SMR as:
Slide 20
SMR with Integrated Piezoresistive Readout So far, the
frequency measurement of our device has relied on measuring the
deflection of a laser beam that is focused onto the tip of the
resonator. The optics used in our lab do not scale favorably for
large arrays and are not suitable for point of-use applications. On
the contrary, Suspended microchannel resonators with integrated
(I.e piezoresistive) readout can measure the mass density of
solutions with high precision.
Slide 21
Slide 22
Basic Operations of piezoresistive SMR Readout of the
resistance change is amplified through a Wheatstone bridge.
Potentiometers are incorporated in order to balance the amplifier
as well as compensate for capacitive coupling of the electrostatic
drive signal. Figure 1 shows the frequency response which
corresponds to superposition of the signal from the resistor and
the drive signal feed through. Measurements of resistance change as
the entire device is heated in a convection oven suggest that a
reasonable bias voltage of 1V on the bridge will result in
biocompatible temperatures of less than 40C.
Slide 23
Slide 24
Slide 25
Fabrication of SMR Hard fabrication techniques used to
mass-produce silicon portion of device. Usually the material use in
this fabrication is silicon. Device is fabricated in two
components, then glass frit-bonding is used. Silicon
cantilever/functional portion Pyrex capping portion, chosen for
transparency.
Slide 26
Silicon Fabrication a. RIE to form channel. b. Structural
material, low-stress SixNy, placed then sacrificial layer of
poly-Si (LPCVP). Removal of poly-Si performed by
chemical-mechanical planarization. c. Another layer of SixNy
deposited, and poly-Si dissolved. d. Chromium placed by ion beam
deposition (provides reflectivity). e. Chromium and SixNy removed
where fluid is in contact with device. f. Bulk micromachining with
TMAH.
Slide 27
Slide 28
Pyrex Fabrication Silicon mask bound to mask and patterned by
DRIE. Deep glass etching performed. Mask patterned by DRIE again.
Gold film deposited. Gold film patterned. Glass fritting printed
onto Pyrex.
Slide 29
Slide 30
Performance factors Selectivity Sensitivity Accuracy Response
time Recovery time Lifetime Reliability Resolution Precision
Slide 31
Advantages of SMR Ability to measure mass density with a
resolution up to 10g/mL. High Precision frequency detection has
enabled the suspended micro-channel resonator (SMR) to weigh single
living cells, single nano-particles, and adsorbed protein layers in
fluid.(I.e Weighing particles with femtogram precision.)
Slide 32
Applications SMR is used as: Bio-molecular detector. Monitoring
cells growth.
Slide 33
Biomolecular Detection
Slide 34
Bio-molecular Detection Since the surface area to volume ratio
of the suspended micro-channel resonator (SMR) is very large,
surface adsorption is an effective mechanism for bio- molecular
mass sensing. The exact mass of an absorbed layer can be quantified
by measuring the difference in resonance frequency before, during
(i.e. in real time) and after each injection. At the surface of the
hollow site, biological recognition agents, can be use to absorbed
the analyte.
Slide 35
Biomolecular Detection
Slide 36
Biological systems the major selective elements They must
attach themselves to one particular substrate, but not to others.
They comprises of the following; Enzymes, Antibodies, Nucleic acids
and, Receptors.
Slide 37
Monitoring Cell Growth G1-synchronized cells have a negative
buoyant mass (positive frequency shift). This cell passes through
the channel floating on the surface of the fluid. This undergoes a
circulation through the channel. The cells entering S phase at a
later time point have a positive buoyant mass (negative frequency
shift). This implies that the cell increases in size since it sink
in the fluid.(I.e implies cell growth)
Slide 38
Monitoring Cell Growth
Slide 39
Slide 40
References 1. Beam model and three dimensional numerical
simulations on suspended microchannel resonators Kuan-Rong Huang,
Jeng-Shian Chang, Sheng D. Chao, and Kuang-Chong Wu 2. Proc Natl
Acad Sci U S A. 2010 January 19; 107(3): 9991004. Published online
2009 December 23. doi: 10.1073/pnas.0901851107 PMCID: PMC2824314
Engineering, Cell Biology.10.1073/pnas.0901851107 3. Suspended
microchannel resonator for improved PSA monitoring. Luke Albares,
griffin, Andy guan, Dillon Achendal, Alex Shepler 4. SUSPENDED
MICROCHANNEL RESONATORS WITH INTEGRATED ELECTRONIC READOUT FOR
BIOMOLECULAR AND SINGLE CELL ANALYSIS R. Chunara1, T.P. Burg2, K.
Payer3, P. Dextras2, S.R. Manalis2 1Harvard-MIT Division of Health
Sciences and Technology, USA 2Department of Biological Engineering,
MIT, USA 3Microsystems Technology Laboratories, MIT, USA