Doxorubicin hydrochloride dox

Polyethylenimine (PEI, average M_w = 25 kDa), tannic acid (1700 Da), poly(N-vinylpyrrolidone) (average M_w = 1300 kDa, PVPON-1300; and 58 kDa, PVPON-58), 46 wt % hydrofluoric acid, fluorescein isothiocyanate (FITC)-dextran, and ethylenediaminetetraacetic acid (EDTA) were purchased from Sigma-Aldrich. Alexa Fluor 488 succinimidyl ester was from Invitrogen. Porous silica (5- and 3-µm average sizes) and solid silica (2.0 ± 0.1 µm) microspheres were obtained from Restek and Polysciences, Inc., respectively. Doxorubicin hydrochloride (DOX) was purchased from LC Laboratories. Ultrapure deionized water (18.2 MΩ cm) was used for solution preparation (Evoqua). NaH₂PO₄ and Na₂HPO₄ buffers of ACS grade (Sigma-Aldrich) were used. Definity (Perflutren Lipid Microspheres) were obtained from Lantheus Medical Imaging, Inc. Poly(methacrylic acid) (PMAA; average M_w = 100 kDa), calcium chloride (CaCl₂), and sodium carbonate (Na₂CO₃) were purchased from Fisher-Scientific. Fetal bovine serum (FBS, 10%) was purchased from Mediatech Inc.

Low-molecular-weight chitosan (85% maximum degree of deacetylation, 15 kDa) was obtained from Polysciences Inc. (Warrington, PA). Acetic anhydride, phosphate-buffered saline (PBS), potassium hydroxide, and the Kaiser Test kit were from Sigma Aldrich (St. Louis, MO). Doxorubicin hydrochloride (DOX) and Gemcitabine hydrochloride (GEM) were obtained from LC Laboratories (Woburn, MA). Triple negative breast cancer cells MDA-MB-231 were purchased from ATCC (Manassas, VA). Dulbecco’s Modified Eagle Medium (DMEM) and fetal bovine serum (FBS) were obtained from Genesee Scientific (San Diego, CA). Penicillin Streptomycin (Pen Strep) was obtained from Gibco (Gaithersburg, MD). 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), was purchased from Invitrogen (Carlsbad, CA). Corning Matrigel Growth Factor Reduced (GFR) Basement Membrane Matrix was purchased from Fisher Scientific (Hampton, NH). All other reagents were of reagent grade or higher.

Graphite powder (4827) was sourced from Asbury Graphite Mills (Lumberton, NC). Doxorubicin hydrochloride (DOX) and Gemcitabine hydrochloride (GEM) were obtained from LC Laboratories (Woburn, MA). The Max8 peptide (VKVKVKVK V^DPPTKVEVKVKV-NH₂),^{63 (link),74 (link),75 (link)} where ^DP represents d-Proline and −NH₂ indicates an amidated C-terminus, was obtained from Genscript (Nanjing, China) at >95% purity. 1,1-Carbonyldiimidazole (CDI), dimethylaminopyridine (DMAP), ethylenediamine (EDA), tris(2-aminoethyl) amine (TREN), acetic anhydride (Ac₂O), benzylamine (BA), succinic anhydride (SA), anhydrous tetrahydrofuran (THF), phosphate buffered saline (PBS), 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES), potassium permanganate (KMnO₄), and hydrogen peroxide (H₂O₂) were purchased from Sigma (St. Louis, MO). Triple negative breast cancer cells MDA-MB-231 were purchased from ATCC (Manassas, VA). Dulbecco’s Modified Eagle Medium (DMEM). Fetal bovine serum (FBS) was obtained from Genesee Scientific (San Diego, CA). Penicillin Streptomycin (Pen Strep) was obtained from Gibco (Gaithersburg, MD). 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), was purchased from Invitrogen (Carlsbad, CA). All other chemicals were of reagent grade or higher.

Doxorubicin hydrochloride (Dox) was purchased from LC Laboratories (Woburn, MA). Stock solutions of Dox were prepared at a concentration of 7 mM in sterile water and stored at 4 °C. Dox was diluted to 12.8 μM in complete growth media immediately prior to use. MCF-7 (wild type or Dox-resistant) cells were incubated through one inlet of the microfluidic device at a concentration of 1×106 cells/mL while Dox was incubated through a separate inlet to ensure that drug exposure occurred only in droplets. The droplets containing single cells were identified and imaged via time-lapse microscopy over 24 h. Dox uptake was assessed using a DsRed filter (Peak Ex/Em-577/602nm) as the excitation and emission wavelengths of Dox are 470 and 585 nm respectively.
Based on dose-dependent responses in microplates, 3.2 μM and 12.8 μM Dox were used for cytotoxicity analysis (Fig. S1). MCF-7 Dox-resistant cells were treated to an additional concentration of 30 μM of Dox. Control cells were incubated in droplets with only growth media (i.e., no Dox). Assessment of cell viability was carried out using a combination of chemical and morphological indicators (Supplementary Fig. S2).