Fig 1.
Overview of the OpenIDS2 synthesizer and its major components.
Fig 2.
Photograph of the fully assembled OpenIDS2 synthesizer.
The system includes the inkjet printing module, amidite ink vials, camera, bulk reagent delivery system, enclosed synthesis chamber, substrate holder (inside chamber), and support jacks.
Fig 3.
Ink supply system and droplet characterization.
(a) Photograph of the ink supply and pressure control system. Each ink vial is connected to a dual-tube configuration: one tube delivers ink to the printhead, while the other is linked to a peristaltic pump and pressure sensor. The pump injects argon gas into the vial to control internal pressure and regulate ink flow. (b) Each droplet is successfully positioned with a 1.4 mm spacing, confirming compatibility of propylene carbonate-based reagents with the Xaar Irix printhead. Scale bar = 1 mm.
Fig 4.
Custom-built peristaltic pump for bulk solution delivery.
(a) Photograph of the assembled peristaltic pump used in OpenIDS2, consisting of a NEMA 23 stepper motor, a 3D-printed chemically resistant housing, and PP tubing. (b) Exploded CAD view showing the internal structure of the pump, including the modular housing, roller assembly, and bearing placement. The design enables easy assembly and maintenance while maintaining chemical resistance through the use of PTFE-wrapped bearings and LCD-printed resin parts.
Fig 5.
Localized sealing mechanism for a compact reaction environment.
(a) While the substrate holder moves along the guide rail attached to the top lid, the PP spring inside the holder remains compressed, exerting upward force. (b) When the holder’s bearings reach the bulk solution dispensing zone and the guide rail ends, the spring lifts the holder slightly, pressing it against the bulk solution nozzle holder to form a temporarily sealed reaction microchamber. (c) After the reaction microchamber is sealed, the bulk solution is dispensed onto the substrate and allowed to react for the designated duration. (d) Upon completion of the reaction, the residual bulk solution is aspirated through a suction inlet positioned below the reaction chamber. However, residual reagent may remain on the surface of the substrate. (e) After the chamber is unsealed, a directed stream of argon gas is blown across the substrate surface to remove residual bulk solution.
Fig 6.
PCB control system architecture and schematic.
(a) Block diagram of the control system architecture for OpenIDS2. The system consists of Arduino Nanos connected via I²C. The master controller manages the bulk solution pumps, solenoid valves, linear stage, and limit sensors. Ink supply controller manages pressure sensors and ink supply pumps, and printhead controllers manage printheads. The master controller communicates with the host PC via USB. (b) Complete circuit schematic designed in EasyEDA, showing modules for motor control, pump drivers, pressure sensor interfaces, printhead circuits, and communication.
Fig 7.
PCB layout and fabricated control board.
(a) Two-layer PCB layout illustrating the routing and placement of key components, including stepper motor drivers, solenoid control, and inkjet printhead interface. (b) Photograph of the assembled control PCB, with Arduino Nanos mounted via pin headers and external device ports connected. Terminal blocks allow quick and reproducible wiring. The board integrates all control functionalities in a compact and reproducible form.
Fig 8.
Oligonucleotides synthesis for functional evaluation of the OpenIDS2.
(a) Urea-PAGE analysis of the synthesized poly(dT) 15-mer. Lane 1: DNA ladder; Lane 2: control 15-mer; Lane 3: synthesized sample. (b) HPLC analysis of the synthesized poly(dT) 15-mer. The stepwise coupling efficiency was estimated to be approximately 96.1% based on the peak areas. Consistent with the PAGE, peaks corresponding to several shorter oligonucletides were also observed. The chromatogram is displayed from 6 minutes onward to exclude the solvent front.