Btpe 50

Microfluidic mother machines allow straightforward, stable culture and observation of individual cells for hundreds of generations, in contrast to microscope culture techniques which do not actively remove progeny during growth. Our devices (23 µm × 1.3 µm × 1.3 µm (l, w, h) growth channels with 5 µm spacing along a split media trench, Supplementary Fig. 2) are fabricated by curing degassed polydimethylsiloxane (Sylgard 184, 1:10 catalyst:resin) against epoxy replicate master molds produced from primary wafer-molded devices^{54 ,55 (link)}. Cured PDMS bulk is peeled from the molds and trimmed as appropriate, input and output ports are punched with electropolished 18ga luer stubs. The PDMS bulk and a clean cover slip are rinsed with 100% isopropanol, blown dry, baked on a hotplate at ~125 °C for 15 min. They are then cooled, and the surfaces to be bonded exposed to air plasma (Harrick PDC-002 plasma cleaner, medium power) for 1 min, and then brought gently into contact. The bonded devices are left at room temperature for 15 min, post baked for 1–2 h at 80 °C, and then stored until use. Polyethylene tubing (Instech, BTPE-50) is press-fitted onto 22ga luer stubs and cannulae (Instech) on opposite ends for coupling to media supplies and waste, and to the devices, respectively.

Comparative PA studies of the different SiNC(1–4) dyes, IRDye800, and ICG were performed using a Vevo 2100 LAZR system (Visualsonics, FujiFilm, ON, Canada) equipped with a 21 MHz transducer (LZ250) and an Nd:YAG laser. Stock solutions (prepared in DMSO) of the different dyes were diluted in PBS at a concentration of 5 µM and loaded in polyethylene tubes (BTPE-50; Instech Laboratories Inc., Plymouth Meeting, PA, USA). Spectral PA measurements were performed in the wavelength range of 680 to 950 nm. PA signal intensity at the absorption maxima of the different dyes (mentioned elsewhere in the manuscript) was used to plot the PA signal intensity versus concentration graph post-adjustment of wavelength-dependent laser output energy. PA imaging parameters—PA gain, laser power, signal intensity, and persistence were kept constant across different measurements. The dye solutions placed inside a tube were also located at the same distance from the transducer to avoid variation in PA signal due to difference in fluence. Image analysis was performed using the built-in VevoLab 5.5.1 software.