Irgacure 2959

Dodecylglyceryl itaconate (DGI) as an amphiphilic
monomer was synthesized from scratch as described elsewhere.^{6 (link)} The crude product was purified by silica gel
column chromatography with a mixture of hexane and ethyl acetate as
the eluant (1:1 by volume). The obtained product was further recrystallized
twice from an acetone/hexane mixture (1:1 by weight). Acrylamide (AAm)
(Wako) as the monomer was recrystallized from chloroform and N,N′-methylenebisacrylamide (MBAA)
(Wako) as the crosslinker was recrystallized from ethanol. Irgacure
2959 (Wako) as the initiator and SDS (Wako), sodium stearate (SST)
(Wako), dodecyltriethylamine chloride (DTAC) (Wako), N-butylamine
(NBA) (Wako) as co-surfactants were used as received. MilliQ water
was used to prepare the precursor solutions and swell the hydrogels.
Paraffin oil (Wako) was used to preserve the hydrogels at the prepared
state in order to prevent any swelling or dehydration.

NIPAM was supplied by Sigma-Aldrich (St. Louis, MO, USA) and further purified by recrystallization from a mixed solution of toluene/n-hexane (6 : 1, v/v). OMAPOSS was purchased from Hybrid Plastics (Hattiesburg, MS, USA) and used as received. 1,4-Dioxane and ethanol were purchased from Titan Scientific (Shanghai, China). Irgacure 2959 was purchased from Wako Pure Chemical Industries (Osaka, Japan). Alpha-minimum essential medium (α-MEM) and phosphate buffer saline (PBS) were purchased from HyClone (South Logan, UT, USA). Fetal bovine serum (FBS), penicillin/streptomycin solution (100×) and trypsin was purchased from Gibco (Grand Island, NY, USA). Cell counting kit-8 (CCK-8) was purchased from Dojindo (Kumamoto, Japan). Ethylenediamine tetraacetic acid (EDTA), trypan blue, calcein-AM, propidium iodide (PI), N,N′-methylenebisacrylamide (MBA), OEGMA (M_n = 500 g mol⁻¹), rhodamine-phalloidin and 4′,6-diamidino-2-phenylindole (DAPI) were purchased from Sigma-Aldrich (St. Louis, MO, USA). Distilled water was prepared using a Milli-Q system (EMD Millipore, Billerica, MA, USA) and used in all experiments.