Two-Photon Laser Microprinting (2PLP): All 3D microstructures were fabricated within a direct laser wri�ng setup (λ = 780 nm, Photonic Professional GT2, Nanoscribe GmbH & Co. KG). PDMS microscaffolds were printed in a dip-in laser lithography (DiLL) configura�on. A droplet of IP-PDMS was placed both at the center of the substrate, with the func�onalized side facing downwards, and on the lens of a 25× objec�ve (NA = 0.8; WD = 380 μm; Zeiss). All PDMS microscaffolds were printed with an op�mized profile, that a contour shell composed of 12 layers (contour distance: 0.2 µm) was first printed with a laser power of 30 mW and a scanning speed of 20 mm/s, and then followed by the filling of the interior (with a laser power of 40 mW, a scanning speed of 100 mm/s, and slicing and hatching distances of 0.3 µm) for each layer. A�er the prin�ng step, the excess of IP-PDMS was removed by placing the substrate horizontally, with the printed side facing downwards, in two separate 2-propanol baths (each containing 10 mL) consecu�vely for 10 minutes and 2 minutes each at room temperature.