Dmem powder

Dulbecco’s modified Eagle’s medium (DMEM), calcium chloride dihydrate (CaCl₂·2H₂O), sodium bicarbonate (NaHCO₃), sodium phosphate monobasic monohydrate (NaH₂PO·H₂O), sodium chloride (NaCl), glucose, HEPES, dimethyl sulfoxide (DMSO) and thiazolyl blue tetrazolium bromide (MTT) were purchased from Sigma-Aldrich (St Louis, MO, USA). DMEM powder, fetal bovine serum (FBS), trypsin-ethylenediaminetetraacetate (trypsin-EDTA) and penicillin–streptomycin were obtained from Gibco BRL (Carlsbad, CA, USA). MS Grade Pierce Trypsin Protease was obtained from Thermo Fisher Scientific (Waltham, MA, USA). Allstars negative siRNA AF 488 (5 nmol) was purchased from QIAGEN. MCF7 and 4T1 cells were obtained from ATCC. Six to eight weeks old BALB/c female mice were bred and maintained at the Animal Facility Unit in Monash University (Sunway campus, Malaysia).

Dulbecco’s modified eagle medium (DMEM), calcium chloride dehydrate (CaCl₂.2H₂O), sodium bicarbonate (NaHCO₃), dimethyl sulphoxide (DMSO), thiazolyl blue tetrazolium bromide (MTT), and ethylene diamine tetraacetic acid (EDTA) were purchased from Sigma-Aldrich (St. Louis, MO). DMEM powder, fetal bovine serum (FBS), trypsin-ethylenediamine tetraacetate (trypsin-EDTA), and penicillin-streptomycin were obtained from Gibco BRL (CA). Caspase-glo 3/7 kit was purchased from Promega (Madison, WI). All siRNAs that have been used in this study and listed in Table 1 were obtained from Qiagen and dissolved in RNase-free water provided by the company to obtain 10 µM stock solution. MCF-7 and 4T1 cells were originally from ATCC.

All reagents and chemicals used were of analytical reagent grade. A glucose standard solution was prepared by dissolving D-(+)-glucose (C₆H₁₂O₆, Sigma-Aldrich, Saint Louis, MO, USA) in a phosphate buffered saline (PBS) pH 7.4 (Amresco Inc, Solon, OH, USA). A glucose-free Dulbecco’s Modified Eagle Medium (DMEM) (Gibco, Thermo Fisher Scientific, Waltham, MA, USA), DMEM powder (Gibco, Thermo Fisher Scientific, USA), fetal bovine serum (FBS) (Thermo Fisher Scientific, USA), and antibiotic-antimycotic (Thermo Fisher Scientific, USA) were used without further purification.
For electrode modification, a 1000 U mL⁻¹ glucose oxidase (GOD) stock solution was prepared by dissolving glucose oxidase (E.C.1.1.3.4) from Aspergillus niger, recombinant (269 U mg⁻¹, Merck, Darmstadt, Germany) in PBS and then diluted to final concentration. A single-walled carbon nanotube (SWCNT, dispersion in H₂O, Sigma-Aldrich, Saint Louis, MO, USA) and colloidal gold (20 nm, Kestrel Bio Science, Bangkok, Thailand) were sonicated for one hour before use. A 1% w/v chitosan solution was prepared by dissolving 1 g of chitosan oligomer (100 mesh, Taming Enterprise, Beijing, China) in 100 mL of 1% acetic acid solution and then purified by dialysis.

Dulbecco’s modified Eagle medium (DMEM) was purchased from BioWhittaker (Walkersville, MD, USA). DMEM powder, foetal bovine serum (FBS) and trypsin-ethylenediamine tetraacetate (trypsin-EDTA) were obtained from Gibco BRL (Carlsbad, CA, USA). Calcium chloride dihydrate (CaCl₂·2H₂O), sodium bicarbonate, dimethyl sulphoxide (DMSO) and thiazolyl blue tetrazolium bromide (MTT) were from Sigma-Aldrich (St. Louis, MO, USA). Streptavidin from Streptomyces avidinii, Poly(ethylene glycol) 2-aminoethyl ether biotin, and fibronectin (derived from human plasma) were obtained from Sigma Aldrich (St. Louis, MO, USA). The chemotherapy drugs, gemcitabine and anastrozole, were purchased from Sigma Aldrich (St. Louis, MO, USA).

Dulbecco’s modified Eagle medium (DMEM), DMEM powder, foetal bovine serum (FBS), TrypLE Express enzyme (1×) (trypsin-EDTA) and penicillin/streptomycin were obtained from Gibco BRL (Carlsbad, CA, USA). Calcium chloride dehydrate (CaCl₂·2H₂O), sodium bicarbonate, hepes, dimethyl sulphoxide (DMSO) and thiazolyl blue tetrazolium bromide (MTT) were from Sigma-Aldrich (St. Louis, MO, USA). Western blots were carried out by the antibodies purchased from Cell Signaling Technology^® (Danvers, MA): Estrogen Receptor α (D8H8) Rabbit mAb, Phospho-Estrogen Receptor α (Ser167) (D1A3) Rabbit mAb, p44/42 MAPK (Erk1/2) (137F5) Rabbit mAb, Phospho-p44/42 MAPK (Erk1/2) (Thr202/Tyr204) (D13.14.4E) XP^® Rabbit mAb, Akt (pan) (C67E7) Rabbit mAb, Phospho-Akt (Ser473) and GAPDH (14C10) Rabbit mAb.