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66 The PCB Magazine • February 2017 After lunch, Prof. Jose Manuel Quero of the SOLAR MEMS Technologies unit at the University of Seville, Spain explained that now was the right time for deployment of PCB technologies in lab-on-chip applications. He considered mature PCB technologies to be a natural partner to LoC development. Examples of devices, including a pressure sensor using capacitance changes in adjacent copper layers, a fluid impulsion device, a flow meter and nebuliser, were explained. The flow meter utilised a tiny wheel produced in copper with an opto coupler to detect and measure air or fluid flow. Flow focussing was the key feature of the nebuliser, using PCB technology to produce the flow focussing elements which can produce a very consistent bubble size for drug delivery. The fluid impulsion device was novel in that it used a fusible element formed in copper as a single-use microfluidic valve. This device demonstrated that a fully integrated microfluidic circuit can be implemented within a PCB substrate without the need of complex interfaces to external impulsion actuation. Quero explained that this technology also brings outstanding advantages of the possibility of integration with sensing and auxiliary electronics and a significant reduction in fabrication cost. A series of microvalves has been characterized varying their parameters of fabrication, leading to a device that requires 0.35 J of electrical energy and supports a range of differential pressures from 50 to 400 kPa. Quero summed up by stating that PCB technology is a good candidate as a lab-on- chip substrate as its flexibility allows for a large diversity of devices and manufacturing techniques and was competitive as a mature technology for mass production of devices. In closing he emphasised the importance of technology transfer from academia to industry to take advantage of the synergies. Next, we learnt about the requirements for fluidic PCB MEMS devices from Prof. Stefan Gassmann, of Jade University of Applied Sciences, Wilhelmshaven, Germany. Gassmann explained the route from the laboratory to full scale production and chose the examples of bubble detectors, active valves, analytical systems, micropumps, static mixers, pressure sensors and a water sample treatment system with which to whet our appetite. He considered the use of PCB technologies as a low-cost route to fabricating MEMS, often utilising non-standard properties. Gassmann explained that, to achieve success in novel application of PCB technology, it was essential to find the right PCB fabricator who was innovative enough to find solutions. A 5 cm x 5 cm monolithic chip system for a miniaturised flow injected analysis system for ferrite ion detection was the next example. The channel structures were formed from four PCBs with a polyimide film forming the pumps. An example of the issues facing novel design was next expounded on a disposable device for genetic testing utilising 32 sensors for DNA detection on a 20μl sample. The device uses PCR for DNA amplification and it was very important that wetted parts should not inhibit the PCR process. It is known that many metals used in PCB fabrication can act as biocides and it was therefore decided to use gold-plated sensors which were known to be inert to the PCR process. However, after initial prototypes were built it was discovered that the standard gold plating was not pure enough with nickel and copper being detected at the EIPC WORKSHOP ON PCB BIOMEMS Prof. Manuel Quero Prof. Stefen Gassmann