Hepes n 2 hydroxyethyl piperazine n 2 ethanesulfonic acid

To obtain inflammatory peritoneal macrophages, 2.5 mL of 3% thioglycolate (Sigma, St. Louis, MO, United States) was injected into the peritoneal cavities of CBA mice, as previously described by Gomes et al. (2003) (link). After 96 h, mice were euthanized, and peritoneal cavities were washed twice using 10 mL of 0.9% NaCl with heparin (20 U.I./mL) (Cristália, Itapira, SP, BR). Next, macrophages were centrifuged at 300 × g under 4°C for 10 min and plated in complete DMEM (Dulbecco’s modified Eagle medium) (Gibco, Grand Island, NY, United States) supplemented with 25 mM HEPES (N-2-hydroxyethyl piperazine-N’-2-ethane-sulfonic acid) (Sigma, St Louis, MO, United States) adjusted to pH 7.4, 2 mM glutamin (Gibco, Grand Island, NY, United States), 20 g/mL ciprofloxacin (Isofarma, Precabura, CE, BR) and 10% inactivated fetal bovine serum (Gibco, Grand Island, NY, United States), then incubated overnight at 37°C under 5% CO₂ and 95% humidity.

Thionine acetate (dye content > 85%), DNA from salmon sperm (Na salt, low mol. weight, ~2000 bp, <5% protein, A_260/280 = 1.4), DNA from calf thymus (Na salt, A₂₆₀/₂₈₀ ≥ 1.8, mol. weight 15.4–17.4 MDa), bovine serum albumin (BSA, lyophilized powder, ≥96%), and HEPES (N-(2-Hydroxyethyl)piperazine-N′-(2-ethanesulfonic acid)) were purchased from Sigma-Aldrich (Darmstadt, Germany). Glucose, citric acid monohydrate, and epirubicin hydrochloride (purity 98.2%) were purchased from Alfa Aesar (Ward Hill, MA, USA). Other reagents were of analytical grade. Deionized Millipore Q^® water (Simplicity^® water purification system, Merck-Millipore, Mosheim, France) was used for the preparation of working solutions. Britton-Robinson buffer containing 0.04 M H₃BO₄, 0.04 M H₃BO₃, 0.04 M CH₃COOH, 0.05 M Na₂SO₄, and pH = 2.0–9.0 was used for the pH dependencies study. Other electrochemical investigations were performed in 0.1 M HEPES containing 0.03 M NaCl, pH 7.0. Electrochemical quartz crystal microbalance (EQCM) measurements were performed in 0.1 M HEPES buffer containing 0.03 M NaNO₃, pH 7.0.

Thionine acetate (dye content > 85%), DNA from salmon sperm (Na salt, low mol. weight, ~2000 bp, <5% protein, A_260/280 = 1.4), DNA from calf thymus (Na salt, A₂₆₀/₂₈₀ ≥ 1.8, mol. weight 15.4–17.4 MDa), bovine serum albumin (BSA, lyophilized powder, ≥96%), and HEPES (N-(2-Hydroxyethyl)piperazine-N′-(2-ethanesulfonic acid)) were purchased from Sigma-Aldrich (Darmstadt, Germany). Glucose, citric acid monohydrate, and epirubicin hydrochloride (purity 98.2%) were purchased from Alfa Aesar (Ward Hill, MA, USA). Other reagents were of analytical grade. Deionized Millipore Q^® water (Simplicity^® water purification system, Merck-Millipore, Mosheim, France) was used for the preparation of working solutions. Britton-Robinson buffer containing 0.04 M H₃BO₄, 0.04 M H₃BO₃, 0.04 M CH₃COOH, 0.05 M Na₂SO₄, and pH = 2.0–9.0 was used for the pH dependencies study. Other electrochemical investigations were performed in 0.1 M HEPES containing 0.03 M NaCl, pH 7.0. Electrochemical quartz crystal microbalance (EQCM) measurements were performed in 0.1 M HEPES buffer containing 0.03 M NaNO₃, pH 7.0.