Tissue-mimetic hydrogels with tunable stiffness

The tissue-mimetic hydrogels were prepared as follows: Acrylamide, N, N methylene-bis-Acrylamide, ammonium persulphate (APS) and N, N, N′, N′-tetramethyl -ethylenediamine (TEMED) were purchased from Sigma-Aldrich. A solution containing Acrylamide monomers, crosslinker N, N methylene-bis-Acrylamide, ammonium persulphate and N, N, N′, N′- tetramethylethylenediamine (TEMED) was prepared. Then various concentrations of GNRs dispersed in PBS were added to the prepared solution and mixed thoroughly. The prepared solution was poured inside a micromachined glass mold to make the desired thickness (300 μm) of the PolyAcrylamide (PAAm) hydrogels. Hydrogels with different stiffness were prepared to investigate the effect of the stiffness on the heat generation. The ratio of Acrylamide%: bis-Acrylamide% was varied (6:0.06, 10:0.1 and 10:0.3) in the process of gel making to adjust the hydrogel stiffness and porosity as reported elsewhere^{70 (link),71 (link)}.