Pdms sylgard 184

The uniaxial stretcher was fabricated by 3D printing (Yale Center for Engineering Innovation and Design, New Haven, CT) as shown in Fig. 1, A and B. Membranes were made from PDMS Sylgard 184 (Dow Corning) by thoroughly mixing the base and curing agent in a 10:1 ratio. Thin (∼400 µm) membranes used ∼7.5 g in a 15-cm Petri plate; thick rings for creating wells used ∼45 g in a 10-cm Petri plate. PDMS was polymerized at 80°C for 3 h for curing. Membranes (29 mm × 44 mm) were cut and attached to the stretcher. Thick PDMS rings with inner diameters of 19 mm was kept on the membranes to create wells to hold the cells and culture medium. The devices were UV sterilized for 20 min in a tissue culture hood and then coated with 10 µg/ml fibronectin. Cells were plated on the membrane at low density for 6 h before stretching. The thick PDMS ring was removed, stretch was applied, and cells were immediately fixed using 4% paraformaldehyde in PBS. Cells were washed four or five times with PBS. The PDMS membranes (in their stretched or unstretched state) were glued to a plastic slide, which was then glued to a glass slide for stability. Cells were mounted using Prolong Gold mounting medium, and the PDMS membranes were cut from the stretcher and imaged within 2–3 d.

Sodium chloride (NaCl), calcium chloride dihydrate (CaCl₂·2H₂O), barium chloride dihydrate (BaCl₂·2H₂O), calcium sulfate dihydrate (CaSO₄·2H₂O), lithium carbonate (Li₂CO₃), and d-glucose were purchased from Sigma-Aldrich. Lithium peroxide (Li₂O₂) was purchased from Alfa Aesar. PFC oil (Krytox GPL103) was purchased from DuPont. PDMS (Sylgard 184) was purchased from Dow Corning. Ultrapure sodium alginate (Pronova SLG100) was purchased from NovaMatrix. The Dental LT Clear resin and flexible resin for 3D printing were purchased from Formlabs. Water was deionized to 18.2 MΩ·cm with the Synergy Ultraviolet Purification System (Millipore Sigma).

InP/ZnS QDs in toluene (5 mg/mL, emission wavelength 610 nm) were purchased from Mesolight (People’s Republic of China). Polystyrene/divinyl benzene beads (diameter 30 µm) were purchased from GE Healthcare (Seoul, South Korea). SU-8 2050 and SU-8 developers were purchased from Micro Chem (Newton, MA, USA). PDMS (Sylgard 184) and a curing agent were purchased from Dow Corning (Midland, MI, USA). MPA, MUA, l-dopamine hydrochloride, adenosine, EDC, NHS, ZnSO₄, and n-hexane were purchased from Sigma-Aldrich (St Louis, MO, USA). Ethanol was purchased from Duksan Pure Chemicals.
Fluorescence emission spectra of the QDs were obtained using a fluoroluminescence spectrometer (Quanta Master, Photon Technology International, NJ, USA) equipped with a xenon lamp (Arc Lamp Housing, A-1010B™), monochromator, and power supply (Brytexbox). Fourier-transform infrared (FTIR) spectra were recorded using a Bruker Vortex 70 FTIR spectrometer. Sonication was performed using a Branson 8510 sonicator. Fluorescence images were obtained using a fluorescence microscope (Nikon, Melville, NY, USA). O₂ plasma treatment was performed using plasma cleaner (Harrick Scientific Co., Germany).