Anhydrous acetonitrile

Sodium hyaluronate (100–150 kDa) was purchased from Lifecore Biomedical. Dialysis membranes Spectra/Por (MW cut off 3.5 kDa) were purchased from SpectrumLabs. Tetrahydrofuran dry, hydrochloric acid (HCl) 37%, Dulbelco’s phosphate buffer saline (DPBS) and sodium chloride were purchased from Fischer Scientific. 3-(Trimethoxysilyl)propyl methacrylate, N-Boc-ethylenediamine, triethylamine anhydrous, acryloyl chloride, dioxane, N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride, 1-hydroxybenzotriazole hydrate, acetonitrile anhydrous, sodium hydrogen carbonate and photo-initiator Irgacure 2959 were purchased from Sigma Aldrich. Calcein AM, propidium iodide, minimum essential medium (MEM) without phenol red, Dulbecco’s modified Eagle medium (DMEM), high glucose Glutamax and fetal bovine serum (FBS) were purchased from Fisher Scientific. RGDSC, 5FAM-RGDSC, GCGYRGDSPG and 5FAM-GCGYRGDSPG peptides were purchased from Innovagen AB. Glass coverslips and absolute ethanol were purchased from VWR. Plus One Repel-Silane ES was purchased from GE Healthcare Life Sciences.

PLGA (Resomer^® RG 504 H, 50:50 lactide:glycolide, acid terminal, MW 38,000–54,000 g/mol), paclitaxel (PTX, MW 853.91 g/mol), rhodamine B (RhB, MW 479.01 g/mol); polyvinlyl alcohol (PVA, MW 9000–10,000 g/mol, 80% hydrolyzed); N,N′-dicyclohexylcarbodiimide (DCC, MW 206.33 g/mol, 99%); N-hydroxysuccinimide (NHS, MW 115.09 g/mol, 98%); dimethylamino pyridine (DMAP, MW 122.17 g/mol, 99%); ninhydrin (MW 178.14 g/mol); ethanolamine (MW 61.08 g/mol, ≥98%); dichloromethane (DCM, ≥99.8%); dimethyl sulfoxide (DMSO, ≥99.9%); acetonitrile anhydrous (ACN, 99.8%); methanol (MeOH, ≥99.9%) were purchased from Sigma–Aldrich Co (St Louis, MO, USA). Chloroform (≥99.8%) was purchased from Honeywell Riedel-de-Haën™ (Charlotte, NC, USA)). Poly (ethylene glycol) diamine (NH₂-PEG-NH₂, 6000 Da) was obtained from Rapp Polymer GmbH, (Tuebingen, Germany).

A solid polymer electrolyte (PEO:CsClO₄) is used for ionic gating. The preparation of the polymer electrolyte is similar to previously published procedures^{45 (link)} with the exception that the electrolyte is prepared and deposited in an argon-filled glovebox where the concentrations of H₂O and O₂ are maintained to be <0.1 part-per-million (ppm). Poly(ethylene-oxide) (PEO) (molecular weight 95,000 g/mol, Polymer Standards Service) and anhydrous CsClO₄ (99.9%, Sigma-Aldrich) are dissolved in anhydrous acetonitrile (Sigma-Aldrich) with an ether oxygen to Cs molar ratio of 76:1 to make a 1 wt% solution. The solid polymer electrolyte is deposited on the sample by drop-casting 25 µL onto the ∼1 × 1 cm² sample. After a 15-minute wait time to allow the majority of the solvent to evaporate, the sample is annealed on a hotplate at 80 °C for 3 mins to drive off remaining solvent. The sample is then transferred from the glovebox to the probe station through an Ar-filled load lock. The entire process of electrolyte preparation, deposition, transfer to the probe station, and measurement are completed under an inert gas environment with no sample exposure to ambient. Electrical measurements are performed on a Lake Shore cryogenic vacuum probe station (CRX-VF) under ∼10⁻⁶ Torr at room temperature using a Keysight B1500A semiconductor parameter analyzer.

Anhydrous acetonitrile (CH₃CN, 99.99 %), sodium acetate (CH₃COONa ⋅ 3H₂O, >99 %), tetrabutyl ammonium hexafluorophosphate ([TBA][PF₆], >99 %), tetrabutyl ammonium tetrafluoroborate ([TBA][BF₄], >99 %), and 2,2′‐bipyridyl (≥99 %) were all purchased from Sigma‐Aldrich. Acetic acid (CH₃COOH, >99.5 %) was purchased from TCI chemicals. Complex [1] precursor dichloro(pentamethylcyclopentadienyl)rhodium(III) dimer [Rh(Cp*)Cl₂]₂ (99 %) was purchased from Strem Chemicals. ILs: 1‐ethyl‐3‐methylimidazolium hexafluorophosphate ([ΕΜΙΜ][PF₆]) (99 %), 1‐ethyl‐3‐methylimidazolium tetrafluoroborate ([ΕΜΙΜ][BF₄]) (>98 %), 1‐butyl‐3‐methylimidazolium hexafluorophosphate ([ΒΜΙΜ][PF₆]) (99 %), and 1‐butyl‐1‐methylpyrrolidinium hexafluorophosphate ([ΒΜΡyrr][PF₆]) (99 %) were all purchased from Io‐li‐tec (Germany). Ferrocene (98 %) was purchased from Merck. All reactants were used without any further purification. All aqueous solutions were prepared with ultrapure water (18.2 MΩ cm, Millipore).