Urea nh2 2co

2-Hydroxyethyl methacrylate monomer (HEMA), gelatin from porcine skin (G, Type B), sodium alginate (A), ethyleneglycol dimethacrylate (EGDMA), as well as crosslinker 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide hydrochloride (EDC), potassium persulfate (PPS), N,N,N′,N′-tetramethylene diamine (TEMED), Pluronic F-172, sodium bicarbonate (NaHCO₃) were purchased from Sigma-Aldrich, St. Louis, MO, USA. RPMI-1640 medium and supplements for cell proliferation as well as 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction assay components were purchased from Sigma-Aldrich. All syntheses were performed in deionized water. Materials used for the hydroxyapatite synthesis and doping were calcium nitrate pentahydrate (Ca(NO₃)₂×5H₂O) (Sigma-Aldrich), magnesium nitrate hexahydrate (Mg(NO₃)₂×6H₂O), strontium nitrate (Sr(NO₃)₂), gallium nitrate hydrate (Ga(NO₃)₃×H₂O), zinc nitrate hexahydrate (Zn(NO₃)₂×6H₂O), ammonium dihydrogen phosphate (NH₄H₂PO₄) were obtained from Sigma-Aldrich, and urea ((NH₂)₂CO) was purchased from Alfa Aesar (Haverhill, MA, USA), and all were of analytical grade. All experiments were performed using lab-produced, ultra-distilled water.

2-Hydroxyethyl methacrylate (HEMA, Sigma-Aldrich, St. Louis, MO, USA), ethyleneglycol dimethacrylate (EGDMA) (Aldrich), potassium persulfate (PPS) (Fluka), and N, N, N′, N′-tetramethylene diamine (TEMED) (Sigma-Aldrich) were used as a monomeric component, crosslinking agent, initiator, and activator, respectively. Natural origin polymeric components, gelatin (type B from bovine skin) (Sigma-Aldrich), and sodium alginate (Sigma-Aldrich), as well as crosslinker 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide hydrochloride (EDC) (Sigma-Aldrich) were used for hydrogel scaffolds syntheses. The deionized water was used as a solvent.
Materials used for the hydroxyapatite synthesis and doping were calcium nitrate pentahydrate (Ca(NO₃)₂ × 5H₂O) (Sigma-Aldrich), magnesium nitrate hexahydrate (Mg(NO₃)₂ × 6H₂O) (Sigma-Aldrich), strontium nitrate (Sr(NO₃)₂) (Sigma-Aldrich), gallium nitrate hydrate (Ga(NO₃)₃ × H₂O) (Sigma-Aldrich), zinc nitrate hexahydrate (Zn(NO₃)₂ × 6H₂O) (Sigma-Aldrich), ammonium dihydrogen phosphate (NH₄H₂PO₄) (Sigma-Aldrich), and urea ((NH₂)₂CO) (Alfa Aesar). All chemicals and reagents were of analytical grade. All experiments were performed using lab-produced, ultra-distilled water.

HEMA, piperazine (PIPz, 99%), di(ethylene glycol)diacrylate and gelatin (type A, porcine), potassium persulfate (PPS, anhydrous), N,N,N′,N′-tetraethylethylene diamine (TEMED), N-Ethyl-N′-(3-dimethyl aminopropyl)carbodiimide hydrochloride (EDC), sodium hydrogen carbonate (NaHCO₃), and polyethylene glycol sorbitan monolaurate (TWEEN 20) used in the cryogel and hydrogel synthesis were purchased from Sigma-Aldrich (St. Louis, MI, USA). All cryogel and hydrogel syntheses were performed in deionized water. Aqueous buffer solutions were prepared using potassium hydrogen phosphates (KH₂PO₄ and K₂HPO₄, Sigma-Aldrich) and deionized water. Materials used for the hydroxyapatite synthesis and doping were calcium nitrate pentahydrate (Ca(NO₃)₂ × 5H₂O) (Sigma-Aldrich), magnesium nitrate hexahydrate (Mg(NO₃)₂ × 6H₂O), strontium nitrate (Sr(NO₃)₂), gallium nitrate hydrate (Ga(NO₃)₃ × H₂O), zinc nitrate hexahydrate (Zn(NO₃)₂ × 6H₂O), and ammonium dihydrogen phosphate (NH₄H₂PO₄) were obtained from Sigma-Aldrich, and urea ((NH₂)₂CO) was purchased from Alfa Aesar (Haverhill, MA, USA), and all were of analytical grade. All experiments were performed using lab-produced, ultra-distilled water.