Browsing by Author "Yang, Tzu-Hsien"

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Facilitating chemical and biochemical experiments with electronic microcontrollers and single-board computers
(1970-01-01)
Prabhu, Gurpur Rakesh D.
;
Yang, Tzu-Hsien
;
Hsu, Chun-Yao
;
Shih, Chun-Pei
;
Chang, Chun-Ming
Since the advent of modern science, researchers have had to rely on their technical skills or the support of specialized workshops to construct analytical instruments. The notion of the 'fourth industrial revolution' promotes construction of customized systems by individuals using widely available, inexpensive electronic modules. This protocol shows how chemists and biochemists can utilize a broad range of microcontroller boards (MCBs) and single-board computers (SBCs) to improve experimental designs and address scientific questions. We provide seven example procedures for laboratory routines that can be expedited by implementing this technology: (i) injection of microliter-volume liquid plugs into microscale capillaries for low-volume assays; (ii) transfer of liquid extract to a mass spectrometer; (iii) liquid-gas extraction of volatile organic compounds (called 'fizzy extraction'), followed by mass spectrometric detection; (iv) monitoring of experimental conditions over the Internet cloud in real time; (v) transfer of analytes to a mass spectrometer via a liquid microjunction interface, data acquisition, and data deposition into the Internet cloud; (vi) feedback control of a biochemical reaction; and (vii) optimization of sample flow rate in direct-infusion mass spectrometry. The protocol constitutes a primer for chemists and biochemists who would like to take advantage of MCBs and SBCs in daily experimentation. It is assumed that the readers have not attended any courses related to electronics or programming. Using the instructions provided in this protocol and the cited material, readers should be able to assemble simple systems to facilitate various procedures performed in chemical and biochemical laboratories in 1-2 d. This protocol provides a set of seven customizable example procedures for using microcontroller boards (MCBs) and single-board computers (SBCs) for applications in chemical and biochemical research.
Microanalysis Using Acoustically Actuated Droplets Pinned Onto a Thread
(2019-01-01)
Yang, Tzu-Hsien
;
Yang, Hao-Chun
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Chang, Cheng-Hao
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Prabhu, Gurpur Rakesh D.
;
Urban, Pawel L.
An acoustic wave-assisted microscale assay platform is demonstrated. Liquid droplets containing samples and reagents are dispensed and pinned onto a hydrophobic thread, and actuated by sound waves. The transport of droplets is achieved by modulating sound emitted by two sources. The resulting sound intensity gradient pushes the droplets in one direction. The available distance of droplet actuation is related to droplet size. The moving droplets merge at the end of their actuation range, and the merged droplet travels further due to its greater size. Fluorometric analysis of the merged droplet is accomplished by positioning an excitation light source above a defined interrogation zone along the thread. The emitted light is analyzed by a miniature spectrometer positioned orthogonally to the excitation light beam. The sound sources and detection system are controlled by universal electronic modules (Raspberry Pi, Arduino). The system is operated automatically with the aid of a custom-developed graphical user interface. Here, we demonstrate its application in enzyme assays (trypsin, beta-galactosidase). In-droplet enzymatic reaction progress curves are readily obtained. The actuated droplets can be put in motion and stopped without a significant delay. Only microliter-range volumes of sample and reagent are consumed in every analysis, while sub-milliliter volumes of chemical waste are produced.