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The use of the smartphone is an ideal platform to realize the future point-of-care (POC) diagnostic system. Herein, we propose an integrated smartphone-based genetic analyzer. It consists of a smartphone and an integrated genetic analysis unit (i-Gene), in which the power of the smartphone was utilized for heating the gene amplification reaction, and the camera function was used for imaging the colorimetric change of the reaction for quantitative and multiplex foodborne pathogens. The housing of i-Gene was fabricated by using a 3D printer, which was equipped with a macro lens, white LEDs, a disposable microfluidic chip for loop-mediated isothermal amplification (LAMP), a thin-film heater, and a power booster. The i-Gene was installed on the iPhone in alignment with a camera. The LAMP mixture for Eriochrome Black T (EBT) colorimetric detection was injected into the LAMP chip to identify Escherichia coli O157:H7, Salmonella typhimurium, and Vibrio parahaemolyticus. The proportional–integral–derivative controller-embedded film heater was powered by a 5.0 V power bank to maintain 63 °C for the LAMP reaction. When the LAMP proceeded, the color was changed from violet to blue, which was real-time monitored by the smartphone complementary metal oxide semiconductor camera. The images were transported to the desktop computer via Wi-Fi. The quantitative LAMP profiles were obtained by plotting the ratio of green/red intensity versus the reaction time. We could identify E. coli O157:H7 with a limit of detection of 101 copies/μL within 60 min. Our proposed smartphone-based genetic analyzer offers a portable, simple, rapid, and cost-effective POC platform for future diagnostic markets.

We present a fully integrated portable centrifugal microsystem for multiplex detection of food poisoning bacteria with a large volume of sample up to 1 mL. The microsystem consists of a portable genetic analyzer and a fully integrated centrifugal microdevice. The centrifugal microdevice is designed with two units: a 3D printed solution-loading cartridge and a centrifugal microfluidic disc. All the essential solutions for loop-mediated isothermal amplification (LAMP) reaction are stored inside the cartridge, and orderly released into centrifugal microdevice by a rotation program. Each unit of the device is designed with 20 reaction chambers for simultaneous detection of food-borne bacteria in one test. To increase the amount of a sample to 1 mL, we incorporated the super absorbent polymer (SAP) in the waste chamber to absorb the sample and the washing solution during the device operation. The whole process was automatically conducted including designated solution release, bead-based DNA extraction, isothermal gene amplification by Eriochrome Black (EBT)-mediated LAMP reaction, and colorimetric and UV–visible detection of amplicons. The ratio between Abs640nm and Abs570nm was used as a criterion to confirm the positive result, and the result was positive upon the condition of Abs640/Abs570 ≥ 1.0. To demonstrate the pathogenic bacteria detection on our proposed microsystem, we targeted three kinds of bacteria (Escherichia coli O157:H7, Salmonella typhimurium, and Vibrio parahaemolyticus) for monoplex and multiplex detection. The whole process from sample to result was completed within 1 h with a low limit of detection (LOD) of 102 cells/mL.

Herein, we present a fully integrated portable centrifugal microsystem for multiplex detection of food poisoning bacteria with a large volume of sample up to 1 mL. The microsystem consists of a portable rotary genetic analyzer and a fully integrated lab-on-a-disc device. The portable rotary genetic analyzer is equipped with a couple of heating blocks, a motor and a UV-Vis optical detector. The device was designed with two units: a 3D printed solution-loading cartridge and a centrifugal microfluidic disc. All the essential solutions for the LAMP reaction (a sample, a washing, an elution and a LAMP cocktail solution) are stored inside the cartridge, and orderly released into centrifugal microdevice by a rotation program. Each unit of the device was designed with 20 reaction chambers for simultaneously detecting 19 kinds of food poisoning bacteria in one test. To increase the amount of a sample to 1 mL, we incorporated the super absorbent polymer (SAP) in the waste chamber to absorb the sample and washing solution during the device operation. The whole process was automatically conducted from bead-based DNA extraction to isothermal DNA amplification by LAMP reaction to colorimetric and UV-vis detection of amplicons in 60 min to identify three kinds of bacteria (Escherichia coli O157:H7, Salmonella Typhimurium, and Vibrio parahaemolyticus).

Due to the requirement of high-voltage power supply, on-chip micro-capillary electrophoresis (μCE) suffers from practical on-site bioapplications. In this paper, we introduced a smart phone based electric power system for μCE on a chip with simple electrical operations and improved portability of a μCE device. Since the power of the smart phone is limited to 5 V, we utilized a boost converter circuit to increase up to 250 V, which enables μCE on a chip. The typical μCE channel with a cross design was patterned on the PMMA substrate, and the sample, the waste, the anode and the cathode reservoirs were fabricated. Two steps of μCE consisting of the injection and the separation were performed to separate two amplicons (121 bp FliC gene of Escherichia coli and 161 bp InvA gene of Salmonella serovar Typhimurium). During the injection step, the voltages applied in the sample and waste reservoirs were 0 V and 250 V, respectively, and the amplicons were filled in the injection channel (6.8 mm length) in 50 s. We switched the power supply to the anode reservoir with 250 V and the cathode reservoir with 0 V. Two amplicons were successfully separated in the separation channel (17 mm length) in 4 min. In order to assign the peak in the electropherogram, we added two bracket ladders with the amplicon sample, so that we could accurately identify the target peak based on a relative migration time.

Herein, we present the fabrication of a novel vertical T-junction based droplet generator using a desktop 3D printer and the production of a variety of size of polymer particles by tuning the vertical T-junction gap height (hg) with ease. The droplet generator device consists of two main components: an internal thread nut with a vertical T-junction droplet generator unit, and a screw with an external thread for adjusting hg. The two components were fabricated by a 3D printer and assembled simply by a bolt-and-nut combination. The clockwise or counter-clockwise rotation of the screw is converted into the downward and upward linear motion of the screw, adjusting the hg value. The hg value can be tuned precisely from 0 to 750 μm by designing 75 control teeth on the top of the screw. The size of the produced droplets is proportional to the hg value. The size range of the droplets was 39–1404 μm, when hg changed from 20 to 200 μm. We synthesized poly(ethylene glycol) diacrylate (PEGDA) particles using the droplet as a reactor, and accordingly the PEGDA particle size could be controlled. Our proposed 3D printed droplet generator is rapid, simple and cost-effective to be fabricated without need of lithographic processes.