Fe3o4 nanoparticles

The precursor fiber was fabricated by the droplet-coating technique. In detail, 640 mg of Fe₃O₄ nanoparticles (50 to 100 nm particle size, Sigma-Aldrich company) and 63 mg of GO (Sigma-Aldrich company) were first added into 1.5 g of mixed Crystal Clear 202 resin [Smooth-On; the initial modulus (at ε = 1%) after annealing was measured to be 1.04 GPa, and the volume expansion ratio was 29.5% at 120°C]. Its base and curing agent (w/w 10:9) are stirred for 1 min. Next, the above mixture was degassed for 5 min. Then, a Nylon 6,6 fiber (Goodfellow) was immersed vertically into the above mixture and then drawn out of the uncured elastomer pool and cured by rapid heating at ~100°C. This step could be repeated multiple times to achieve the desired thickness (fig. S15). After drying at 30°C for 6 hours, the above fiber was then immersed vertically into a freshly mixed PDMS base and curing agent (w/w 10:1, Sylgard 184, Dow Corning). The fiber was then drawn out from the uncured PDMS pool and cured by heating at ~90°C. Last, after drying the above fiber at 30°C for 8 hours, the precursor fiber was obtained.

Sodium alginate (Sigma-Aldrich,
Cat. W201502), FeCl₃ (Sigma-Aldrich, Cat. 236489), Fe₃O₄ nanoparticles (Sigma-Aldrich, Cat. 637106),
glucose (Sigma-Aldrich, Cat. G8270), and potassium nitrate (Penta,
Cat. 12970) were employed as received. Dry yeast Saccharomyces
cerevisiae (Fermentis, SafAle S-04) and dried wort (Agra
group, a.s.) were used. All solutions were prepared in tap water if
not otherwise indicated.

A total of 50,000 SCC cells were grown on glass slides overnight. The next day, the cells were subsequently exposed to fluorescently labeled liposomes DSPC:SM:DOTAP:chol, molar% 20:30:20:30, respectively, labeled with Texas Red^® DHPE (0.5 molar%, ThermoFisher) for 30 min. Liposomes were loaded with Fe₃O₄ nanoparticles (0.3 mg/mL) and calcein (10 µM) (Sigma, Neustadt, Germany). Cells were also treated with SMase (0.4 U/mL, 30 min) or radiated (24 Gy) and further exposed to a temperature-controlled AMF (6 mT, 20 min). Controls were solely treated with liposomes or also exposed to an AMF (6 mT, 20 Min) or SMase (0.4 U/mL, 30 min), respectively. The final treatment time and microscopy imaging time (endpoint at 30 min) was the same for all the cell groups and done in RT. After the treatments, the cells were washed three times with PBS in order to wash out free drug and liposomes that were not associated with the cells and fixed with 4% PFA. The fluorescence of calcein (496 nm excitation and 508 nm emission) and liposomal Texas Red (589 nm excitation and 615 nm emission) was imaged with a Zeiss Axio observer Z1 using AxioVision SE64 software or confocal laser scanning microscope Leica SP5 (Objective: HCX PL APO CS 63x/1.4 OIL).

Fe₃O₄ nanoparticles (Sigma-Aldrich, USA) (30 wt% of PUU-PCL) were added to the PUU solution and the mixture was cast and dried on a metal wire to obtain 20 cm long PUU tubes with 2.5 mm diameter and 0.5 mm tube wall thickness. The tubes were expanded in diameter by passing a thicker metal wire through the tubes in 55 °C water and cooling the tubes back to room temperature while the metal wires were in the tubes. One end of the tubes was coiled by bending the tubes with the metal wire, generating PUU-PCL ureteral stents.
Porcine ureters were purchased from a butcher’s shop and washed with PBS. The PUU-PCL ureteral stents were inserted into the porcine ureters, leaving both the coiled end and the straight end outside the corresponding ends of the porcine ureters. The assembly of one porcine ureter and one PUU-PCL stent were fixed onto a universal mechanical testing machine, with the lower clamp fixing the straight end of the PUU-PCL stent, the upper clamp fixing the porcine ureter tissue adjacent to the coiled end of the PUU-PCL stent. The PUU-PCL stents were pulled from the porcine ureters and the resistance force was recorded (n = 3).

We used biotinylated microparticles with 1-dimensional (1D) magnetic nanoparticle chains. These biotinylated microparticles were fabricated via a conventional photolithography technique. The prepolymer solution was prepared by mixing 79% (v/v) poly(ethylene glycol) diacrylate (PEG-DA) (M_n = 700; Sigma-Aldrich), 4% (v/v) photoinitiator (2-hydroxy-2-methylpropiophenone 97%, Sigma-Aldrich), 17% (v/v) Deionized (D.I) water, 8 mg/mL Acrylate-PEG-Biotin (PEG M_n = 2000; CreativePEGWorks, Durham, NC, USA), and 4 mg/mL Fe₃O₄ nanoparticles (50 nm; Sigma-Aldrich, St. Louis, MO, USA). Here, Fe₃O₄ magnetic nanoparticles were used to make self-assembled 1D magnetic nanoparticle chains for magnetization patterning. Then, 15,225 microparticles with 1D magnetic chains were polymerized simultaneously with 5 s exposure of UV with a 18.6 mW/cm² intensity, under a 3000 Gauss neodymium magnet. The microparticles were 100 µm in diameter and 70 µm in height (more information described in Supplementary Material Figures S1–S5). The fabricated microparticles were stored in 1% bovine serum albumin (BSA)—phosphate buffered saline (PBS) solution to block the reactive functional group and to prevent nonspecific binding.