Fuel cell-powered microfluidic platform for lab-on-a-chip applications: Integration into an autonomous amperometric sensing device{ J. P. Esquivel,* a J. Colomer-Farrarons, b M. Castellarnau, c M. Salleras, a F. J. del Campo, a J. Samitier, bde P. Miribel-Catala ` b and N. Sabate ´ a Received 17th August 2012, Accepted 29th August 2012 DOI: 10.1039/c2lc40946a The present paper reports for the first time the integration of a microfluidic system, electronics modules, amperometric sensor and display, all powered by a single micro direct methanol fuel cell. In addition to activating the electronic circuitry, the integrated power source also acts as a tuneable micropump. The electronics fulfil several functions. First, they regulate the micro fuel cell output power, which off-gas controls the flow rate of different solutions toward an electrochemical sensor through microfluidic channels. Secondly, as the fuel cell powers a three-electrode electrochemical cell, the electronics compare the working electrode output signal with a set reference value. Thirdly, if the concentration measured by the sensor exceeds this threshold value, the electronics switch on an integrated organic display. This integrated approach pushes forward the development of truly autonomous point-of-care devices relying on electrochemical detection. Introduction The advantages of microfluidics in life sciences applications have been widely discussed in an increasing number of papers published during the past decades. 1 This research has mainly focused on the development of central laboratory testing and point-of-care (POC) diagnostics, each having particular require- ments depending on the application. The most promising opportunities of POC diagnostics stem from their portability, short sample processing time and flexibility. Recently published reviews in this field agree on how the ideal POC device should be. This device should detect several analytes with high sensitivity and short response time. It should include microfluidics, sensors and electronics, all powered by a built-in energy source within a compact package. 2–4 Furthermore, the growing interest in paper- based devices for diagnostics will most probably re-define the concept of future developments. 5–7 However, current POC devices still require hand-held readers or bench top instruments to perform the measurements and display the results of the analytical test. 8 This peripheral equipment must also include active pumps to flow the sample. The dependence on external equipment limits portability and autonomy of the POC device. This work builds on our recently reported integration of a micro fuel cell into a micro fluidic platform. 9 As it was stated there, the potential implementation of this kind of power source within lab-on-a-chip systems would provide not only pumping capabilities but also high power density and long-time operation. This work turns that original idea into a reality, and reports for the first time the integration of a microfluidic system, electronics modules, an electrochemical sensor and a display, all powered by a single micro direct methanol fuel cell (mDMFC). The sensing is performed by amperometry, which measures the electric current flowing through a working electrode at a set electrode potential. Such current is directly proportional to the concentration of analyte. While optical detection methods predominate in lab on a chip devices due to their selectivity and sensitivity, ampero- metry offers similar sensitivities but compromises selectivity in favour of simpler and lower cost instrumentation, as well as allowing the measurement of turbid samples. The device presented here works as follows. The fuel cell powers the electronic module, which has three functions. First, it regulates the flow rates of different solutions pumped towards the amperometric sensor through microfluidic channels. Secondly, it acquires the signal of the sensor using a three- electrode configuration. Lastly, if the concentration measured by the sensor exceeds a set threshold value, it sends a signal to an organic display to provide a reading. a Instituto de Microelectro ´nica de Barcelona, IMB-CNM (CSIC) Campus UAB, 08193, Bellaterra, Barcelona, Spain. E-mail: juanpablo.esquivel@imb-cnm.csic.es; Tel: + 34 935947700 b Discrete to Integrate Lab (D2I), Department of Electronics, Bioelectronics and Nanobioengineering Research Group (SIC-BIO), University of Barcelona, Martı ´ i Franque `s 1, Planta 2, 08028 Barcelona, Spain c Research Laboratory of Electronics, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA d Institute for Bioengineering of Catalonia (IBEC), C/Baldiri Reixac 10-12, 08028 Barcelona, Spain e Centro de Investigacio ´n Biome ´dica en Red en Bioingenierı ´a Biomateriales y Nanomedicina (CIBER-BBN), C/Marı ´a de Luna 11, Edificio CEEI, 50018 Zaragoza, Spain { Electronic Supplementary Information (ESI) available: Details on the electronics module configuration. See DOI: 10.1039/c2lc40946a Lab on a Chip Dynamic Article Links Cite this: Lab Chip, 2012, 12, 4232–4235 www.rsc.org/loc TECHNICAL INNOVATION 4232 | Lab Chip, 2012, 12, 4232–4235 This journal is ß The Royal Society of Chemistry 2012 Downloaded by CNM. Instituto de Microelectrónica de Barcelona on 08 October 2012 Published on 31 August 2012 on http://pubs.rsc.org | doi:10.1039/C2LC40946A View Online / Journal Homepage / Table of Contents for this issue