N isopropylacrylamide nipam

N-isopropylacrylamide (NIPAM) (Sigma-Aldrich, St. Louis, MO, USA), purity 97%, and N,N′-methylene-bis-acrylamide (BIS) (Eastman Kodak, Rochester, NY, USA), electrophoresis grade, were purified by recrystallization from hexane and methanol, respectively, dried under reduced pressure (0.01 mmHg) at room temperature and stored at −20 °C. Sodium dodecyl sulphate (SDS), purity 98% and potassium persulfate (KPS), purity 98% were purchased from Sigma-Aldrich (St. Louis, MO, USA) and used as received. Ultrapure water (resistivity: 18.2 MW/cm at room temperature) was obtained with Millipore Direct-Q^® 3 UV purification system (Darmstadt, Germany). 3-(trimethoxysilyl)propyl methacrylate (TMSPMA) and trimethoxy(octyl)silane (TMOS) were purchased from Sigma-Aldrich. All the other solvents (Sigma Aldrich RP grade) were used as received. Dialysis membrane, SpectraPor^® 1, MWCO 6–8 kDa (Spectrum Laboratories, Inc., Piscataway, NJ, USA) was soaked in distilled water for 2 h and then thoroughly rinsed before use. Cover glasses, round with a diameter of 12 mm, were purchased from Heinz Herenz Medizinalbedarf GmbH (Hamburg, Germany) and used as support for the film deposition.

N-n-propylacrylamide (NNPAM) was synthesized via a Schotten–Baumann reaction published by Hirano et al. [61 (link)]. For this reaction, acryloylchloride (Sigma-Aldrich Chemie GmbH, Munich, Germany; purity 98%), n-propylamine (Fluka, Sigma-Aldrich Chemie GmbH, Munich, Germany; purity 99%), triethylamine (Grüssing GmbH Analytika, Filsum, Germany; purity 99%), and methylenechloride (p.a.) were used as received. The obtained monomer NNPAM was washed with $\mathrm{N}\mathrm{a}\mathrm{H}\mathrm{C}{\mathrm{O}}_3$ (10 wt%) and dried over $\mathrm{M}\mathrm{g}\mathrm{S}{\mathrm{O}}_4$ . After filtration, the solvent was evaporated and the product was distilled in vacuum (115 °C, 10 mbar). N-isopropylacrylamide (NIPAM; Sigma-Aldrich Chemie GmbH, Munich, Germany; purity 97%) and N-isopropylmethacrylamide (NIPMAM; Sigma-Aldrich Chemie GmbH, Munich, Germany; purity 97%) were purified by recrystallization from hexane. The cross-linker N,N’-methylenebisacrylamide (BIS; Sigma-Aldrich Chemie GmbH, Munich, Germany; purity 99%), the initiator ammonium persulfate (APS; Sigma-Aldrich Chemie GmbH, Munich, Germany; purity ≥98%), and pyrene (Sigma-Aldrich Chemie GmbH, Munich, Germany; purity ≥99%) were used without further purification. For all experiments, purified water from an Arium pro VF system (Sartorius AG, Göttingen, Germany) was used.

A Surfactant Free Emulsion Polymerisation (SFEP) technique was used for the preparation of p(NIPAM)-co-5%AA as described previously and in accordance with literature [27 (link),28 (link),29 (link),41 (link)]. Briefly, a three-neck lid was then fitted to the reaction vessel, which was placed onto a hot plate stirrer and heated to 70 °C with continuous stirring under N2 atmosphere. Potassium persulphate initiator (0.5 g) was dissolved in 800 mL of distilled water. The crosslinker N,N′-methylenebisacrylamide 99% (0.5 g) (BS, Sigma Aldrich, Gillingham, UK), N-isopropylacrylamide (NIPAM, Sigma Aldrich, Gillingham, UK) 97% monomer (4.75 g) and acrylic acid (AA, Sigma Aldrich, Gillingham, UK) co-monomer (0.25 g) were dissolved in 200 mL of distilled water while stirring gently with a magnetic stirrer. After all the reagents were dissolved, they were transferred into the reaction vessel containing the initiator. The reaction was run for 6 h with constant stirring and under nitrogen. After 6 h, the microgel dispersion was allowed to cool down to room temperature, then dialyzed (MW cut-off was 12–14,000 kDa) in fresh distilled water for 7 days.

Styrene (ST, Ukraine) of p.a. quality was purified via standard method directly before polymerization. N-isopropylacrylamide (NIPAM, Sigma-Aldrich Inc.), N,N′-methylenebisacrylamide (BIS, Sigma-Aldrich Inc.), potassium persulfate K₂S₂O₈ (KPS, Ukraine), sodium phosphate monobasic dihydrate NaH₂PO₄ × 2H₂O (KPS, Ukraine), were of reagent grade and used without further purification. HPPH (2-[1-hexyloxyethyl]-2-devinyl pyropheophorbide-alpha) was purchased from Raybiotech, China. Phosphate-buffered saline with pH 7.4 (PBS) was purchased from Gibco Life Technologies (AG, Switzerland). 9,10-anthracenediyl-bis(methylene)dimalonic acid (ABDA), anionic surfactant sodium dodecyl sulfate (SDS), chloroform, and dimethyl sulfoxide (DMSO) were purchased from Sigma Aldrich (Saint Louis, MO). Two 2-azaazulene polymethine dyes with different conjugation lengths (JB7-08 and JB17-08) were synthesized as described previously [25 (link)].

N-isopropylacrylamide (NIPAM) (97% purity), methylene-bis-acrylamide (MBA), chitosan from shrimp shell (molecular weight 190–310 kDa, deacetylation rate 75–85%), glacial acetic acid, ammonium persulfate (APS), and tetramethylethylenediamine (TEMED) were obtained from Sigma Aldrich (Overijse, Belgium). Calcein AM, ethidium homodimer, phosphate buffered saline (PBS), Gibco minimum essential alpha medium, gibco antibiotic-antimycotic, and Biowest fetal bovine serum (FBS) were obtained from ThermoFisher Scientific (Merelbeke, Belgium).