Alginic acid

All chemicals were purchased at reagent grade or better from the Sigma-Aldrich company (St. Louis, MO), unless otherwise noted. Iron (III) oxide nanopowder, less than 50 nm in size, was examined for hyperthermia applications, primarily as a low-cost, abundant nanomaterial. fluidMAG D with starch coating, and fluidMAG PAD with polyacrylamide coating were purchased from chemicell GmbH (Berlin, Germany), with a reported concentration of 100 mg/mL (which included the weight of the polymer coating). Both fluidMAG particles had a reported hydrodynamic radius of 50 nm. Additional iron oxide NPs dispersed in hexane were synthesized as described below, using iron(III) acetylacetonate 97%, 1,2-hexadecanediol 90%, oleic acid 90%, oleylamine 70% (Sigma-Aldrich, St. Louis, MO), benzyl ether 99% (Acros Organics, Fair Lawn, NJ), hexane, and ethyl alcohol. Table 1 lists the types, abbreviations, sizes, and concentrations of particles used for this study. alginic acid, sodium salt (Acros Organics, rated at 485 mPa-s for a 1% solution at 20 °C) was used to modify the viscosity of aqueous NP dispersions. Calcium chloride was purchased from Fisher Scientific (Fair Lawn, NJ) to cross-link alginic acid solutions.

To determine the viability of the ferromagnetic interface system to be used as a 360-degree interface system, the ability for waste and nutrients to diffuse through the interconnected micropores of the magnetic porous required investigation. Therefore, a diffusivity study of the composite interfaces was performed by developing a magnetic composite reservoir with a 5 x 5 mm cylinder well with 3 mm thick porous walls. The diffusivity would be measured by the absorbance of a 5% (w/w) alginate sol gel (Alginic acid, Fischer Scientific) with 15 mg/mL of aniline blue (Fischer Scientific) in the bulk fluid. The reservoirs were first submerged in 1 mL of PBS in 24 well plates and preconditioned via physical agitation to allow for PBS to enter the pores of magnetic porous composites. The alginate/ aniline blue sol gel was then loaded in a 1 mL syringe with a 26 G needle and 100 μL of solution was injected into each magnetic composite reservoir, followed by the addition of another 800 μL of DPBS. The cumulative mass transport out of the magnetic reservoir composites was measured by removing 200 μL for absorbance analysis of the well plate bulk solution outside the composite interface at specified time points (20, 40, 60, 80, 100, 120, and 150 min), 200 μL of PBS was added after each time point. Studies were completed in triplicates for both grid and gyroid reservoirs magnetic composites.