| Title: | Accurate dispensing of volatile reagents on demand for chemical reactions in EWOD chips |
| Author(s): | Ding H; Sadeghi S; Shah GJ; Chen S; Keng PY; Kim CJ; van Dam RM; |
| Address: | "Crump Institute for Molecular Imaging, University of California, Los Angeles, Los Angeles, CA, USA" |
| ISSN/ISBN: | 1473-0189 (Electronic) 1473-0197 (Print) 1473-0189 (Linking) |
| Abstract: | "Digital microfluidic chips provide a new platform for manipulating chemicals for multi-step chemical synthesis or assays at the microscale. The organic solvents and reagents needed for these applications are often volatile, sensitive to contamination, and wetting, i.e. have contact angles of <90 degrees even on the highly hydrophobic surfaces (e.g., Teflon(R) or Cytop(R)) typically used on digital microfluidic chips. Furthermore, often the applications dictate that the processes are performed in a gas environment, not allowing the use of a filler liquid (e.g., oil). These properties pose challenges for delivering controlled volumes of liquid to the chip. An automated, simple, accurate and reliable method of delivering reagents from sealed, off-chip reservoirs is presented here. This platform overcomes the issues of evaporative losses of volatile solvents, cross-contamination, and flooding of the chip by combining a syringe pump, a simple on-chip liquid detector and a robust interface design. The impedance-based liquid detection requires only minimal added hardware to provide a feedback signal to ensure accurate volumes of volatile solvents are introduced to the chip, independent of time delays between dispensing operations. On-demand dispensing of multiple droplets of acetonitrile, a frequently used but difficult to handle solvent due to its wetting properties and volatility, was demonstrated and used to synthesize the positron emission tomography (PET) probe [(18)F]FDG reliably" |
| Keywords: | Electrowetting Fluorodeoxyglucose F18/chemistry Hydrophobic and Hydrophilic Interactions Microfluidic Analytical Techniques/*instrumentation Positron-Emission Tomography Solvents/chemistry Volatile Organic Compounds/*chemistry; |
| Notes: | "MedlineDing, Huijiang Sadeghi, Saman Shah, Gaurav J Chen, Supin Keng, Pei Yuin Kim, Chang-Jin C J van Dam, R Michael eng U54 CA151819/CA/NCI NIH HHS/ U54CA151819/CA/NCI NIH HHS/ Research Support, N.I.H., Extramural Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, Non-P.H.S. England 2012/07/25 Lab Chip. 2012 Sep 21; 12(18):3331-40. doi: 10.1039/c2lc40244k. Epub 2012 Jul 23" |
