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Real-time multianalyte biosensors based on interference-free multichannel monolithic quartz crystal microbalance
(2015-05-05)
Jaruwongrungsee, Kata
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Waiwijit, Uraiwan
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Wisitsoraat, Anurat
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Sangworasil, Manas
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Pintavirooj, Chuchart
In this work, we design, fabricate and characterize a new interference-free multichannel monolithic quartz crystal microbalance (MQCM) platform for bio-sensing applications. Firstly, interference due to thickness-shear vibration mode coupling between channels in MQCM array is effectively suppressed by interposing a polydimethylsiloxane wall between adjacent QCM electrodes on a quartz substrate to form inverted-mesa-like structure. In addition, the electrical coupling due to the electrical impedance of solution is diminished by extending the flow path between them with an extended-design flow channel. The electrical testing results show that individual QCM signal is unaffected by those of adjacent channels under liquid loading, signifying the achievement of interference-free MQCM. The MQCM is applied for multi-analyte biosensing of IgG and HSA. The anti-IgG and anti-HSA are separately immobilized on two adjacent QCM electrodes, which are subsequently blocked with BSA to avoid unspecific binding. The MQCM biosensors are tested with single- and double-analyte solutions under continuous flow of buffer. The IgG and HSA QCM sensors only show frequency shift responses to their corresponding analytes and there are very small cross frequency shifts due to remnant unspecific binding. Moreover, MQCM sensors show approximately linear frequency shift response with analyte concentration. Therefore, the developed MQCM platform is promising for real-time interference-free label-free detection and quantification of multiple bio-analytes.
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Metamaterial-inspired microfluidic-based sensor for chemical discrimination
(2012-12-01)
Jaruwongrungsee, Kata
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Withayachumnankul, Withawat
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Wisitsoraat, Anurat
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Abbott, Derek
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Fumeaux, Christophe
This work proposes a metamaterial-inspired microfluidic-based chemical sensor. The sensor comprises a microwave split-ring resonator (SRR), an important building block of metamaterials, integrated with a disposable flow-channel made of a transparency film. The electromagnetic response of the sensor is observed in the presence of various analytes including glycerol, ethanol, and phosphate buffered saline. It is found that the resonance frequency in the transmission amplitude and the zero crossing in the reflection phase of the sensor are good features for discrimination of these analytes and for determining their concentrations. The developed metamaterial-inspired microfluidic-based chemical sensor has a potential for advanced chemical sensing applications. © 2012 IEEE.
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On-chip cell separation and manipulation using traveling wave dielectrophoretic force controlled by four-phase signal generator
(2011-12-01)
Jaruwongrangsee, Kata
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Maturos, Thitima
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Bunthawin, Sakshin
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Wisitsoraat, Anurat
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Sangworasil, Manas
In this work, we present a device for cell manipulation and separation using travelling wave dielectophoretic (twDEP) force. The device consists of microchamber and 16 parallel electrode array controlled by four-phase signal. The dielectrophoretic PDMS chamber and Cr/Au parallel electrode array were fabricated by standard microfabrication techniques. The driving signals for the twDEP system are produced by a specially designed four-phase signal generator. The signal generator can be operated in a fixed or±90° phase shift mode with varying frequency, applied voltage and shift interval. In addition, the signal conditions can be store to and retrieved from a built-in database. The twDEP system was tested with polystyrene microspheres suspension in de-ionized water and red blood cells in D-mannitol solution. Cells responded to the electric field in various mechanisms depending on the applied signals conditions. The results showed that the twDEP force occurred when the applied signals were 10 V (50 kHz-700 kHz) and 7V (30 kHz-1MHz) for 4.5 μm and 10 μm microspheres respectively. The mixed solution containing equal amount of 4.5 and 10 μm microspheres were used for separation test. Under the signal conditions for 10 μm microspheres, the microspheres were moved under twDEP force while the smaller microspheres were attached to the electrodes. Therefore, the twDEP device can successfully manipulate and separate the microspheres of different sizes, and it can be further applied for cells selection. © 2011 IEEE.
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High-sensitivity humidity sensor utilizing PEDOT/PSS printed quartz crystal microbalance
(2011-08-12)
Jaruwongrungsee, Kata
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Sriprachuabwong, Chakrit
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Sappat, Assawapong
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Wisitsoraat, Anurat
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Phasukkit, Pattarapong
In this work, quartz crystal microbalance humidity sensor was fabricated by inkjet printing technique. Poly (3, 4-ethylenedioxythiophene)/poly-styrene- sulfonic acid (PEDOT/PSS), one of the most widely used polymer composites, was printed on QCM electrode as sensing layer using Dimatrix material inkjet printer. The main advantage of this coating method is its high precision of solution coating with accurately controlled volume and area. The printed layer was varied from 1 to 20 layers. With 20 PEDOT/PSS printed layers, the humidity sensitivity is found increased by more than three orders of magnitude compared to uncoated QCM. In addition, the PEDOT/PSS coated QCM exhibits fast humidity detection with short response and recovery times. Thus, the PEDOT/PSS printed on the QCM electrode is an effective way to improve humidity-sensing characteristic of QCM. © 2011 IEEE.
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Symmetrical poly MUMPs-based piezoresistive microcantilever sensors with on-chip temperature compensation for microfluidics applications
(2008-05-01)
Tuantranont, Adisorn
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Lomas, Tanom
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Jaruwongrungsee, Kata
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Jomphoak, Apichai
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Wisitsoraat, Anurat
Microelectromechanical systems (MEMS)-based cantilever beam sensors for microfluidics applications with on-chip temperature sensors for temperature drift compensation were developed. The stress induced on gold surface with polysilicon piezoresistive sensing is demonstrated. In principle, adsorption of biochemical species on a functionalized surface of the microfabricated cantilever will cause surface stress and, consequently, cantilever bending. The sensing mechanism relies on the piezoresistive properties of the doped polysilicon wire encapsulated in the beam. The beam is constructed through multiusers MEMS Process (PolyMUMPs) foundry with postprocessing silicon etching. Bending analysis is performed so that the beam tip deflection can be predicted. The piezoresistor designs on the beams were varied, within certain constraints, so that the sensitivity of the sensing technique could be measured by external read-out circuit. The mass detection of 0.0058-0.0110 g is measured by the beam resistor series as a balanced Wheatstone bridge configuration. The voltage output of the bridge is directly proportional to the amount of bending in the MEMS cantilever. The temperature dependency and sensor performance have been characterized in experiments. Compensation by resisters on the substrate significantly reduces the temperature dependence. © 2008 IEEE.

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