Polydimethylsiloxane

PVDF-HFP pellets with (Mw ∼ 400,000 kg mol-1), indium tin oxide (ITO) coated polyethylene terephthalate (PET) electrodes with an average area of 20 mm × 10 mm, and polydimethylsiloxane (PDMS) were purchased from Sigma-Aldrich Chemical Co. (United States). CB particles with average diameter of 40 nm was purchased from Alfa Aesar (United States). Solutions were prepared using N, N-dimethylformamide (DMF) and acetone (ACE) both purchased from Sigma Aldrich.

Commercially available reagents were utilized for the synthesis of the AAP photomolecule and PDMS–AAP composite films. N-methylhydrazine, 1-bromo-6-hexanol, ethyl acetate, Na₂SO₄, K₂CO₃, acetone, potassium iodide, 4-aminophenol, 2,4-pentanedione, dichloromethane, and polydimethylsiloxane (elastomer and curer) were procured from Sigma–Aldrich, St. Louis, MO, USA and used as received.

CS (MW of 50–190 kDa, DA: 15–25%), DS (MW of 7–20 kDa), PEI (MW of 1.3 kDa), polysorbate 80, Leu, Mant, Mans, doxorubicin hydrochloride, polydimethylsiloxane (PDMS), o-phthaldialdehyde (OPA), 2-mercaptoethanol, acetonitrile, sodium bicarbonate, dimethyl sulfoxide (DMSO), fluorescein isothiocyanate isomer I (FITC), cellulose dialysis tubing with cutoff 12 kD MWCO, and benzoylated dialysis tubing with cutoff 2000 NMWCO were purchased from Sigma Chemical Co. (St. Louis, MO, USA). miRIDIAN microRNA Mimics for precursor hsa-mir-34a-5p was purchased from PerkinElmer. Non-small human adenocarcinoma epithelial cell line (A549) and mouse embryonic fibroblast cell line NIH/3T3 (ATCC CRL-1658TM) were obtained from the European Collection of Authenticated Cell Cultures (ECACC). Roswell Park Memorial Institute (RPMI) 1640 Medium, Dulbecco’s Modified Eagle Medium (DMEM), Trypsin-EDTA, and fetal bovine serum (FBS) were purchased from Biosera (France). Antibiotic–antimycotic and MTT were prepared from Biowest (USA) and Duchefa (Biochemie, Netherlands), respectively. All other chemicals used in the study were of analytical grade.

Human cardiac troponin I (cTnI, 98%), human cardiac troponin T (cTnT, 98%), sodium periodate (NaIO₄, 98%), sodium hydroxide (NaOH, 99%), hydrogen chloride (HCl, 12 N), (3-aminopropyl)triethoxysilane (APTES), glutaraldehyde, luteinizing hormone (LH, 98%), human chorionic gonadotropin (HCG, 98%), follicle stimulating hormone (FSH, 95%), thyroid stimulating hormone (TSH, 98%), and polydimethylsiloxane (PDMS, 99%) were purchased from Sigma Aldrich (MO, USA). All the other reagents and chemicals used in this study were of analytical grade and were used as received without any purification unless specified.

The CNTs were grown by chemical vapour deposition (CVD) following a previously described route66 . In short, a 1–5 nm thick iron catalyst film was deposited onto a silicon substrate bearing a thin silicon dioxide layer and a mixture of helium (95 wt%) and acetylene (5 wt%) was used as the CVD feedstock for growing CNT at a temperature between 650 and 750 °C67 . These CNTs typically have an outer diameter of ∼10–15 nm and a length of 150–300 μm. The CNT BP membranes were processed by vacuum filtration of CNTs dispersed in 99.8% pure propan-2-ol (Aldrich 99.9%)68 . Well-dispersed CNT suspensions were obtained by repeated sonication at intervals of 15 minutes and a power of 150 W. Vacuum filtration was performed using a 47 mm diameter Millipore filtration unit attached to line vacuum (dP = −95 kPa). The CNTs were filtered onto a poly (ether sulphone) 0.2-μm pore size Millipore membrane and then peeled off to form a self-supporting membrane. The thickness of the BPs were on the order of 20+/−2 μm. All other chemicals (polydimethylsiloxane, 2-methyl imidazole, zinc nitrate hexahydrate) and gases (Analytical air, O₂ in Ar, H₂ in Ar, CO₂) used in this study were purchased from Sigma Aldrich or BOC. The composition of the gas was 28 v% O₂ in Ar, Ar and CO₂ of analytical grade (purity >99.99%) or 2 v% H₂ in Ar.

All procedures were carried out according to animal welfare guidelines authorized by the Baylor College of Medicine IACUC committee. All surgeries were performed under general anesthesia with 1.5% isoflurane. The mouse head was fixed in a stereotactical stage (Kopf Instruments), and eyes were protected with a thin layer of polydimethylsiloxane (30,000 cst, Sigma-Aldrich). After removing the scalp, a custom-made titanium headplate was attached to the skull with dental acrylic (Lang Dental). A 3 mm wide circular craniotomy centered 2.5 mm lateral of the midline and 1.2 mm anterior of the lambda suture was made, targeting the middle of the monocular region of left V1. A coverglass with a hole for pipette access was placed on the brain and carefully anchored with vetbond glue (3M, Saint Paul, MN) and dental acrylic (Lang Dental).