Sodium poly 4 styrene sulfonate

Iron(II) sulfate, ammonium chloride, 25% ammonia solution, and o-phosphoric acid were purchased from Reakhim (Moscow, Russia). Sodium hydroxide was obtained from LenReaktiv (St. Petersburg, Russia). 1,2-Propylene glycol was the product of EKOS-1 (Moscow, Russia). D-Glucose monohydrate was obtained from LenReaktiv (St. Petersburg, Russia). Anhydrous sodium hydrogen phosphate (≥99.0%) and potassium dihydrogen phosphate (≥99.5%) used to prepare the buffer solutions were purchased from Sigma-Aldrich (St. Louis, MO, USA). All chemicals were of analytical grade and were used as received. Dextran ((C₆H₁₀O₅)_n M_r~40.000), sodium poly(4-styrenesulfonate) (PSS, M_r~70.000) and branched polyethylenimine (PEI, M_r~25,000) were obtained from Sigma-Aldrich, DOX (lyophilizate for solution for injection, 10 mg/ampoule) was obtained from Pharmachemie (Petah Tikva, Israel). All solutions were prepared using ultrapure water obtained from a Milli-Q system, Millipore Corporation (Millipore SAS, Molsheim, France).

Tetrachloroauric acid trihydrate (99.99%), sodium citrate dihydrate (≥ 99%), Triton X-100 (laboratory grade), sodium borohydride (≥ 98%), silver nitrate (> 99%), poly(Ethylene glycol) methyl ether thiol (mw 2000), poly(allylamine) hydrochloride (PAH, mw 50000), sodium poly(4-styrene sulfonate) (PSS, mw 70000), nitric acid (≥ 65%), nitric acid (1M), hydrochloric acid (≥ 37%), sulfuric acid (95.0–97.0%), hydrogen peroxyde (30% w/w), ethanol (≥ 99.8%), 2-propanol (99.5%), and ethyl cellulose (10 cP; 22 cP; 46 cP; 100 cP) were bought from Sigma Aldrich (Milano, Italy); α-mercapto,ω-carboxy poly(Ethylene glycol) (mw 3000), poly(Ethylene glycol) methyl ether thiol (mw 5000), poly(Ethylene glycol) methyl ether thiol (mw 10000), and poly(Ethylene glycol) methyl ether thiol (mw 20000) were bought RAPP Polymere (Tübingen, Germany); Ethylene glycol (99.5%) and ammonia solution in water (30% w/w) were bought from Carlo Erba Reagenti S.p.A. (Milano, Italy) Glass coverslides (22 × 26 mm, 0.14 mm thickness) were bought from Delchimica Scientific Gòassware (Napoli, Italy).

Diazabicycloundec‐7‐ene (DBU, 98%), concentrated hydrochloric acid (HCl, 37%, ACS reagent), azobisisobutyronitrile (AIBN, recrystallized from methanol), tetrahydrofuran (THF, HPLC grade), dichloromethane (DCM, ACS grade), hexanes (technical grade), 4,4′‐trimethylenedipiperidine (97%), sodium poly(4‐styrenesulfonate) (SPS, M_w = 70,000), and ethyl acetate (ACS grade, >99.5%) were purchased from Sigma‐Aldrich (Milwaukee, WI). 3‐Dimethylamino‐1‐propanol (99%) was purchased from Acros Organics (Morris Plains, NJ). 1,4‐Butanediol diacrylate was purchased from Alfa Aesar (Ward Hill, MA). Anhydrous THF was obtained from a Pure Process Technology solvent purification system (Nashua, NH). Linear poly(ethyleneimine) (LPEI, MW = 25000) was obtained from Polysciences, Inc. (Warrington, PA). Inhibitor Removal Resin was purchased from Alfa Aesar (Radnor, PA). 2‐Vinyl‐4,4‐dimethylazlactone (VDMA), a kind gift from Dr. Steven M. Heilmann (3M Corp., Minneapolis, MN) was fractionally distilled under vacuum (B.P. ∼22°C at ∼500 mTorr; clear mobile liquid at room temperature) and then stored with 500 ppm butylated hydroxytoluene (BHT) and 1000 ppm triethylamine at 0°C prior to use. Polymer 1 (M_n = 23.3 kDa, Ð = 2.39) was synthesized as previously described.36 Phosphate‐buffered saline (PBS, pH = 7.4, ionic strength = 154 mM) was prepared by dilution of commercially available concentrate (EM Science, Gibbstown, NJ). Plasmid DNA [pEGFP‐N1 (encoding enhanced green fluorescent protein; EGFP) and pDsRed2‐N1 (encoding red fluorescent protein; RFP; pRFP) (4.7 kb), >95% supercoiled] was obtained from Elim Biopharmaceuticals, Inc. (San Francisco, CA). Dulbecco's modified Eagle's medium (DMEM), fetal bovine serum (FBS; 10%), penicillin (100 units/mL), streptomycin (100 μg/mL), Opti‐MEM reduced serum medium, trypsin‐EDTA (0.25%), and Lipofectamine 2000 were purchased from Invitrogen (Carlsbad, CA). COS‐7 cells were obtained from the American Type Culture Collection (Manassas, VA). Expired stainless steel stents used for SEM studies (Abbott Vascular, Abbott Park, IL; Medtronic, Shoreview, MN) were obtained from the Cardiovascular Physiology Core Facility at the University of Wisconsin‐Madison. All stents had nominal diameters ranging from 2 to 5 mm and lengths ranging from 8 to 30 mm. Stent expansion was performed using a standard inflation device with deionized water as the expansion fluid. All buffers and polymer solutions were filtered through a 0.2 μm membrane syringe filter prior to use unless noted otherwise. Test‐grade n‐type silicon wafers were purchased from Silicon Inc. (Glenshaw, PA). Water with a resistivity of 18.2 MΩ was obtained from a Millipore filtration system. Materials were used as received unless otherwise noted.