Browsing by Author "Chen, Chih-Lin"

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Dual robotic arm "production line" mass spectrometry assay guided by multiple Arduino-type microcontrollers
(2017-02)
Chen, Chih-Lin
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Chen, Ting-Ru
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Chiu, Shih-Hao
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Urban, Pawel L.
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應用化學系
Chemistry-related procedures often involve a substantial investment of manual work. Automated procedures have been developed to reduce the burden of sample processing and analysis. Here, we demonstrate an automated system for sequential sample processing and delivery to a mass spectrometer. This new platform referred to as RAMSAY-2 incorporates two robotic arms. The arms are guided by several inexpensive, open-source, electronic modules. RAMSAY-2 performs various operations on the samples. Two robotic arms work synchronously to process multiple samples. The system recognizes the delivered samples, aliquots solutions (e.g., substrates of biochemical reactions, diluents), incubates the samples with the reagents, delivers the processed samples to the ion source of the mass spectrometer, and initiates data acquisition. The increased efficiency and versatility are due to implementation of two arms, several microfluidic pumps, fast servos, and the modular design of the control unit. RAMSAY-2 handles multiple sample processing workflows encoded in radio frequency identification tags attached to the samples and can easily be reprogrammed according to the specific requirements of sample processing before mass spectrometric detection. As an example, we demonstrate that RAMSAY-2 can autonomously collect data to evaluate enzymatic activities in enzyme samples supplied by the user. (C) 2016 Elsevier B.V. All rights reserved.
Facile multi-dimensional profiling of chemical gradients at the millimetre scale
(2016-01-01)
Chen, Chih-Lin
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Hsieh, Kai-Ta
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Hsu, Ching-Fong
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Urban, Pawel L.
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應用化學系
A vast number of conventional physicochemical methods are suitable for the analysis of homogeneous samples. However, in various cases, the samples exhibit intrinsic heterogeneity. Tomography allows one to record approximate distributions of chemical species in the three-dimensional space. Here we develop a simple optical tomography system which enables performing scans of non-homogeneous samples at different wavelengths. It takes advantage of inexpensive open-source electronics and simple algorithms. The analysed samples are illuminated by a miniature LCD/LED screen which emits light at three wavelengths (598, 547 and 455 nm, corresponding to the R, G, and B channels, respectively). On presentation of every wavelength, the sample vial is rotated by similar to 180 degrees, and videoed at 30 frames per s. The RGB values of pixels in the obtained digital snapshots are subsequently collated, and processed to produce sinograms. Following the inverse Radon transform, approximate quasi-three-dimensional images are reconstructed for each wavelength. Sample components with distinct visible light absorption spectra (myoglobin, methylene blue) can be resolved. The system was used to follow dynamic changes in non-homogeneous samples in real time, to visualize binary mixtures, to reconstruct reaction-diffusion fronts formed during the reduction of 2,6-dichlorophenolindophenol by ascorbic acid, and to visualize the distribution of fungal mycelium grown in a semi-solid medium.
Nucleotide-Dependent Bioautocatalytic Timer Reaction
(2016-09)
Chen, Ting-Ru
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Hsu, Ching-Fong
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Chen, Chih-Lin
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Witek, Henryk A.
;
Urban, Pawel L.
We describe a biochemical timer composed of three biocatalytic reactions involving three types of adenylate nucleotides: adenosine triphosphate (ATP), adenosine diphosphate (ADP), and adenosine monophosphate (AMP). The timer is triggered by a small amount of ATP or ADP. An abrupt increase in the ATP concentration (following numerous amplification cycles) leads to a sudden increase of luminescence from the reaction mixture. The time point when the luminescence appears is found to be a function of the initial concentration of the triggering nucleotide (5.0 X 10(-8)-1.0 X 10(-6) M), even in the presence of a complex biological matrix. The mechanism of the observed dependence of the time of luminescence increase on the concentration has been confirmed with simple kinetic models. Due to the biocompatibility of the proposed trienzymatic reaction scheme (sensitivity to common nucleotides and occurrence in a neutral pH aqueous environment), the scheme can be used in bioengineered systems that require modulation of the response time (light emission) by concentration.