Publications by authors named "Dedy H B Wicaksono"

4 Publications

  • Page 1 of 1

Cotton fabric-based electrochemical device for lactate measurement in saliva.

Analyst 2014 Jun 29;139(12):3009-16. Epub 2014 Apr 29.

Faculty of Biosciences and Medical Engineering (FBME), Universiti Teknologi Malaysia (UTM), 81310 Skudai, Johor, Malaysia.

Lactate measurement is vital in clinical diagnostics especially among trauma and sepsis patients. In recent years, it has been shown that saliva samples are an excellent applicable alternative for non-invasive measurement of lactate. In this study, we describe a method for the determination of lactate concentration in saliva samples by using a simple and low-cost cotton fabric-based electrochemical device (FED). The device was fabricated using template method for patterning the electrodes and wax-patterning technique for creating the sample placement/reaction zone. Lactate oxidase (LOx) enzyme was immobilised at the reaction zone using a simple entrapment method. The LOx enzymatic reaction product, hydrogen peroxide (H2O2) was measured using chronoamperometric measurements at the optimal detection potential (-0.2 V vs. Ag/AgCl), in which the device exhibited a linear working range between 0.1 to 5 mM, sensitivity (slope) of 0.3169 μA mM(-1) and detection limit of 0.3 mM. The low detection limit and wide linear range were suitable to measure salivary lactate (SL) concentration, thus saliva samples obtained under fasting conditions and after meals were evaluated using the FED. The measured SL varied among subjects and increased after meals randomly. The proposed device provides a suitable analytical alternative for rapid and non-invasive determination of lactate in saliva samples. The device can also be adapted to a variety of other assays that requires simplicity, low-cost, portability and flexibility.
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http://dx.doi.org/10.1039/c4an00201fDOI Listing
June 2014

Flexible microfluidic cloth-based analytical devices using a low-cost wax patterning technique.

Lab Chip 2012 Jan 17;12(1):209-18. Epub 2011 Nov 17.

Medical Device and Implant Technology Group (Mediteg), Dept. of Biomechanics and Biomedical Materials, Faculty of Health Science and Biomedical Engineering, Universiti Teknologi Malaysia, 81310, Johor, Malaysia.

This paper describes the fabrication of microfluidic cloth-based analytical devices (μCADs) using a simple wax patterning method on cotton cloth for performing colorimetric bioassays. Commercial cotton cloth fabric is proposed as a new inexpensive, lightweight, and flexible platform for fabricating two- (2D) and three-dimensional (3D) microfluidic systems. We demonstrated that the wicking property of the cotton microfluidic channel can be improved by scouring in soda ash (Na(2)CO(3)) solution which will remove the natural surface wax and expose the underlying texture of the cellulose fiber. After this treatment, we fabricated narrow hydrophilic channels with hydrophobic barriers made from patterned wax to define the 2D microfluidic devices. The designed pattern is carved on wax-impregnated paper, and subsequently transferred to attached cotton cloth by heat treatment. To further obtain 3D microfluidic devices having multiple layers of pattern, a single layer of wax patterned cloth can be folded along a predefined folding line and subsequently pressed using mechanical force. All the fabrication steps are simple and low cost since no special equipment is required. Diagnostic application of cloth-based devices is shown by the development of simple devices that wick and distribute microvolumes of simulated body fluids along the hydrophilic channels into reaction zones to react with analytical reagents. Colorimetric detection of bovine serum albumin (BSA) in artificial urine is carried out by direct visual observation of bromophenol blue (BPB) colour change in the reaction zones. Finally, we show the flexibility of the novel microfluidic platform by conducting a similar reaction in a bent pinned μCAD.
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http://dx.doi.org/10.1039/c1lc20764dDOI Listing
January 2012

Time-domain Optical Coherence Tomography system with integrated delay line for surgical guidance applications.

Annu Int Conf IEEE Eng Med Biol Soc 2010 ;2010:3017-20

Electronic Instrumentation Laboratory, Delft University of Technology, 2628CD, The Netherlands.

Optical Coherence Tomography is a high resolution imaging technique able to provide in-depth information about living tissue. Among all its applications, it can be argued that surgical guidance is one of the most demanding in terms of system reliability, footprint and cost. In order to enable faster adoption of this technology in that field, we had already developed and demonstrated a new type of scanning delay line based on the thermo-optic effect of silicon. By changing the temperature of an integrated waveguide, we are able to produce a variation in optical delay. In this paper, we demonstrate the inclusion of such a device in a complete system and the performance levels that can be achieved with this technique. In particular, we show a line scan rate of 2kHz with good linearity and a scan range of 0.95mm in air. These values meet the needs of most surgical guidance applications.
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http://dx.doi.org/10.1109/IEMBS.2010.5626164DOI Listing
March 2011

On-chip biosensing of estrogen receptor-alpha at single molecular level.

Biosens Bioelectron 2004 Jul;19(12):1573-9

Department of Biological Information, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8501, Japan.

A novel method for detecting interaction between DNA and DNA-binding protein at single molecular level has been proposed. In this study, estrogen receptor-alpha (ER-alpha) was used for biosensing as the proof-example. A 518 bp-long (ca. 176 nm) DNA probe labeled with streptavidin at its 5'-terminus was prepared by inserting a consensus oligonucleotide sequence that binds to ER-alpha. A solution containing ER-alpha was dropped onto the Ni-treated mica substrate on which the DNA prove was previously immobilized, and it was observed by AFM. Specific binding of ER-alpha could be observed by measuring the distance between the site where binding occur, to the streptavidin label.
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http://dx.doi.org/10.1016/j.bios.2003.12.028DOI Listing
July 2004