Confocal imaging experiments were conducted on an inverted Zeiss LSM 710 AxioObserver (Zeiss, Oberkochen, Germany). Images were acquired at room temperature using a 40× water objective (LD C-Apochromat 40×/1.1 NA W Corr M27, Zeiss) with the correction collar set for a No. 1 coverslip. Rhodamine-labeled PA gels were fabricated on No. 1 coverslips and imaged using a DPSS-561 laser at 0.25% power, using the MBS488/561/633 beam splitter and the Zen 2010 software (Zeiss). Z-stack images were acquired with a step size of 0.42 μm with line scanning at x = y=z = 0.42 μm pixel size.
Widefield epifluorescence images for microparticle imaging were obtained on an Olympus IX-71 inverted microscope with an Olympus LCPlanFI 40×/0.6 NA) objective and an EMCCD Camera iXon2 (Andor). For microparticle imaging, brightfield microscopy was first utilized to find the field of view including a microparticle in a microwell. Microparticles were then imaged with an exposure time of 50 ms using a Cy5 filter cube (Chroma, 49009) using a time series feature in MetaMorph (Molecular Devices). Images were collected every 1 s. For particle tracking, microparticles were imaged using an Olympus UPlanFi 10×/NA 0.3 objective at an exposure time of 500 ms and an EMCCD Camera iXon2 (Andor).
Widefield epifluorescence images for microparticle imaging were obtained on an Olympus IX-71 inverted microscope with an Olympus LCPlanFI 40×/0.6 NA) objective and an EMCCD Camera iXon2 (Andor). For microparticle imaging, brightfield microscopy was first utilized to find the field of view including a microparticle in a microwell. Microparticles were then imaged with an exposure time of 50 ms using a Cy5 filter cube (Chroma, 49009) using a time series feature in MetaMorph (Molecular Devices). Images were collected every 1 s. For particle tracking, microparticles were imaged using an Olympus UPlanFi 10×/NA 0.3 objective at an exposure time of 500 ms and an EMCCD Camera iXon2 (Andor).