Autocad

The mechanical properties of the IJP PDMS-based sensor depend on the shape of the conductive pattern. Six different patterns were designed, fabricated, and evaluated where the evaluation is explained in details in Section 2.4. The horseshoe pattern sustains large amount of strains as reported in reference [16 (link)] that reached up to 25% depending on its dimensions, therefore, all the designs were based on the horseshoe shape. Figure 3 shows the six horseshoe designs based on the horseshoe arrays.
The patterns were designed using AutoCAD (2018, Autodesk, Autodesk, San Rafael, CA, USA) and then exported as dxf files to Eagle (2018, Autodesk, Autodesk, San Rafael, CA, USA). Eagle was used to convert the dxf files into images with a certain resolution. The images were then modified with GNU Image Manipulation (GIMP, Berkeley, CA, USA) and made suitable for the inkjet printer pattern editor.
In inkjet printing, different printheads and drop spacing (DS) were used for different patterns. The 10 pL printhead was used in this study for Patterns 4, 5, and 6. For Patterns 1, 2, and 3, the 1 pL printhead was used due to the small features with 500 and 720 µm line widths and distance between lines of less than 100 µm. For the 10 pL printhead, 30 $\mathrm{DS}$ was adopted as in existing studies [16 (link),38 (link)]. For the 1 pL printhead, 15 DS was selected after optimization.

The multi-level microchannel was designed in AutoCAD (AutoDesk, San Rafael, CA, USA) and exported to GDS format for maskless lithography using KLayout. The design consists of three layers: the first alignment mask layer, the flow channel layer, and the growth channel layer (Figure 1). The flow channel layer (for nutrient delivery and bacterial removal) was 15 $\mathsf{\mu }$ m in depth and the growth channel layer (for bacterial entrapment, outgrowth, and long-term imaging) was 1 $\mathsf{\mu }$ m in depth.
To create the microstructure mold, we developed a lithography approach using a single negative photoresist (mr-DWL-5, Micro Resist Technology GmbH, Berlin, Germany) and a maskless writer (DL-1000, Nanosystem Solutions, Okinawa, Japan). The hard baking temperature and exposure dosage protocol was based on the manufacture instructions. Briefly, after lithographic exposure, the wafer was hard baked and developed in propylene glycol methyl ether acetate (PGMEA, Sigma-Aldrich, Burlington, MA, USA), washed thoroughly with isopropanol, and dried with nitrogen air. The true depth of the microstructures was confirmed with a stylus profilometer (DektakXT, Bruker, Billerica, MA, USA).

The SATE animation was made in Adobe Inventor (Adobe Systems) using objects drawn in AutoCAD (Autodesk). Adobe Premiere Pro CC (Adobe Systems) was used for final editing and to add the music track, voice-over and subtitles.

Microchannel devices were based on previous designs (36 ) and were drawn using a computer-aided design software (AutoCAD; Autodesk, San Rafael, CA). Quartz-chrome photomasks containing the device patterns were produced from these designs using Minnesota Nano Center facilities and were used to create master molds for device designs on silicon wafers using standard photolithography techniques. Photolithography, PDMS replica molding, and device assembly are described in detail in the Supporting Materials and Methods.

Master template of nanowell array was designed using AutoCAD (2012, Autodesk, San Rafael, CA, USA) as described previously [2 (link),3 (link),6 (link)] and fabricated on a silicon wafer using soft lithography techniques. Nanowell array was fabricated by spinning silicon wafer poured with a Polydimethylphenylsiloxane (PDMS) mixture at 1000 rpm for 30 s and then baking at 80 °C for 3 h in an oven. The dimension of each nanowell was 50 $\mathsf{\mu }$ m × 50 $\mathsf{\mu }$ m. After detaching nanowell array from the master, it was air plasma oxidized and attached to the bottom of a 50-mm glass bottom petri dish. Nanowell array was plasma re-oxidized prior to use.