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An innovative modular approach for facile design and construction of flexible microfluidic biosensor platforms based on a dry manufacturing "craft-and-stick" approach is developed. The design and fabrication of the flexible graphene paper electrode (GPE) unit and polyethylene tetraphthalate sheet (PET)6/adhesive fluidic unit are completed by an economic and generic xurographic craft approach. The GPE widths and the microfluidic channels can be constructed down to 300 mu m and 200 mu m, respectively. Both units were assembled by simple double-sided adhesive tapes into a microfluidic integrated GPE (MF-iGPE) that are flexible, thin (<0.5 mm), and lightweight (0.4 g). We further functionalized the iGPE with Prussian blue and glucose oxidase for the fabrication of MF-iGPE glucose biosensors. With a closed-channel PET fluidic pattern, the MF-iGPE glucose biosensors were packaged and sealed to protect the integrated device from moisture for storage and could easily open with scissors for sample loading. Our glucose biosensors showed 2 linear dynamic regions of 0.05-1.0 and 1.0-5.5 mmol L-1 glucose. The MF-iGPE showed good reproducibility for glucose detection (RSD < 6.1%, n = 6) and required only 10 mu L of the analyte. This modular craft-and-stick manufacturing approach could potentially further develop along the concept of paper-crafted model assembly kits suitable for low-resource laboratories or classroom settings., Funding Agencies|Royal Golden Jubilee Ph.D. Scholarship from the Thailand Research Fund under the Office of the Prime Ministry, the Royal Thai Government [PHD/0213/2560]

The design of a smartphone imaging surface plasmon resonance (Smart-iSPR) system integrated with an affordable 3D-printed microfluidic SPR chip fabricated via a facile manufacturing approach could pave the way towards the development of miniaturized and integrated smartphone iSPR biosensors for emerging point-of-use applications. Conventional smartphone-based SPR systems using soft photolithography for the fabrication of microfluidics SPR chips are costly, labour-intensive and required a specially-equipped light-controlled environment, that is inadequate and mismatched with the consumer-based smartphone detection platform. Herein, we report the design, fabrication and testing of an innovative print-and-stick unibody microfluidics coupled SPR chip for smartphone iSPR. The 3Dprinted microfluidics (~V0.006) is assembled via an aptly-sized adhesive tape with the gold SPR sensing surface. Such a simple integrated microfluidic SPR chip with the print-and-stick configuration has a high resistance to fluid leakages at the channel-to-sensor interface with pressure up to 66.9 Pa and the tubingto-inset interfaces with pressure up to 86.9 Pa. The smartphone iSPR platform weighs 138 g and with a dimension of around 70 x 60 x 40 mm3, and its performance was characterized using a standard Biacore (R) 02-microglobulin calibration kit. The sensorgrams obtained by the smartphone iSPR show all the typical characteristics for surface functionalization, association and dissociation events. The smartphone iSPR responds linearly to 02-microglobulin within the range of 10-200 nM (R2 = 0.986) with a limit-ofdetection (LOD) of 1.5 nM. Given the miniaturized feature and simple camera-based imaging smartphone iSPR, the analytical performance is satisfactory when compared with the analytical dynamic range of 2 -32 nM described in the Biacore (R) protocol.(c) 2022 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/b, Funding Agencies|European UnionEuropean Commission [720325]

We present a low-cost, accessible, and rapid fabrication process for electrochemical microfluidic sensors. This work leverages the accessibility of consumer-grade electronic craft cutters as the primary tool for patterning of sensor electrodes and microfluidic circuits, while commodity materials such as gold leaf, silver ink pen, double-sided tape, plastic transparency films, and fabric adhesives are used as its base structural materials. The device consists of three layers, the silver reference electrode layer at the top, the PET fluidic circuits in the middle and the gold sensing electrodes at the bottom. Separation of the silver reference electrode from the gold sensing electrodes reduces the possibility of cross-contamination during surface modification. A novel approach in mesoscale patterning of gold leaf electrodes can produce generic designs with dimensions as small as 250 mu m. Silver electrodes with dimensions as small as 385 mu m were drawn using a plotter and a silver ink pen, and fluid microchannels as small as 300 mu m were fabricated using a sandwich of iron-on adhesives and PET. Device layers are then fused together using an office laminator. The integrated microfluidic electrochemical platform has electrode kinetics/performance of Delta E-p = 91.3 mV, I-pa/I-pc = 0.905, characterized by cyclic voltammetry using a standard ferrocyanide redox probe, and this was compared against a commercial screen-printed gold electrode (Delta E-p = 68.9 mV, I-pa/I-pc = 0.984). To validate the performance of the integrated microfluidic electrochemical platform, a catalytic hydrogen peroxide sensor and enzyme-coupled glucose biosensors were developed as demonstrators. Hydrogen peroxide quantitation achieves a limit of detection of 0.713 mM and sensitivity of 78.37 mu A mM(-1) cm(-2), while glucose has a limit of detection of 0.111 mM and sensitivity of 12.68 mu A mM(-1) cm(-2). This rapid process allows an iterative design-build-test cycle in under 2 hours. The upfron, Funding Agencies|Ministry of Higher Education, MalaysiaMinistry of Education, Malaysia [FRGS17-030-0596]; Asian Office of Aerospace Research and Development (AOARD) [FA23861814105, FA23861814048]