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54 PCB007 MAGAZINE I JANUARY 2024 now focuses on paper, its use is only just begin- ning. Table 1 lists several characteristics of each of these materials. Operating Sequences It is quite remarkable what can be accom- plished on a miniaturized scale. Once the technology of MEMS was perfected on sili- con wafers using the photolithography, etch- ing, metallization, and lamination processes, it became possible to miniaturize chemical anal- ysis. But it was discovered that certain activi- ties could be achieved in the micro and fluidic arena that did not have an equivalent in the larger real-world, such as electrophoresis (fluid movement by surface tension and applied volt- ages). Once a sample has been deposited on the inlet port to a LoC or LoPCB, electro-osmotic fluid movement takes over and various actions are accomplished; the sample can be heated, passed over a stationary bed of reagents, and additional fluids can be added by the external device and mixed. e sample can be reacted in reaction chambers, and then passed to vari- ous sensors for analysis. One of the unique variations is in the Agilent DNA and RNA Analyzer that, aer the LoC cell (Figure 3e) has prepared the sample, it is fed into a nano-inkjet cartridge that deposits thousands of nano-drops on a prepared optical slide with thousands of micro-spots to react to the prepared sample. Aer incubation, a laser scanner records the results and prints out a final report (Figure 3f ). Figure 3 shows several of these sequences and sensors that today offer medical diagno- sis in a few minutes. is used to take clinical laboratories weeks to perform, and new tech- niques like DNA and RNA analysis were not even dreamt about a few years ago. Examples In Figure 4, University of Bath researchers started with LoC experiments then progressed to using PCBs. Now LoPCB components are available, like DNA sensors and heater-on-a- PCB (Figures 4a–c). e process is fabricat- ing fluidic channels and sensors/activators and bonding biosensor chip before final seal- ing (Figure 4d). e performance and illustra- tion of lactose and glucose PCB plated sensors is shown in Figure 4e. Figure 4f shows a poly- imide (PI) flexible PCB with copper- (Cu) and gold- (Au) plated sensors, coated with a gel of EDOT on a graphene carrier of AuNPs and GOx (WE). Figure 5 shows the microfluidic elements of which fluidics/osmatic fluid movement is par- amount. e use of photosensitive dry film sol- der mask is used for forming fluidic networks, as seen in Figure 5a. Figure 5b shows CAD design Table 1: Base materials for LoC and LoPCB formations 1