1 pentanol

We used the following chemicals for synthesis and preparation of silica fibers: Poly(N-vinylpyrrolidone) (PVP; M_w 55,000 g mol^-1; Sigma-Aldrich, USA), 1-pentanol (98%; Carl Roth, Germany), ethanol (99%; Fisher Chemicals, USA), sodium citrate dihydrate (99%; Carl Roth), aqueous ammonia solution (30-33%; Carl Roth), tetraethoxysilane (TEOS; 98%; Sigma-Aldrich), and sodium hydroxide (Fisher Chemicals). UltraPure sterile nuclease-free water (Invitrogen, USA) was used for all fiber syntheses to ensure the microbiological purity of the samples, which was a necessary criterion for all biological studies. Autoclaved pure water (ELGA Purelab, UK) was used for all other purposes. Sterile disposable laboratory materials (Sarstedt, Germany) and chemically purified, heat-sterilized, and depyrogenated (250 °C, 1 h) laboratory glassware were used for syntheses and handling of the samples. The silica fibers and the reference samples were dispersed in Dulbecco's phosphate-buffered saline (DPBS; Gibco, USA) for solubility studies.

All dicarboxylic acids (oxalic, succinic, suberic, and sebacic), methanol, 1-decanol, and tetradecanol were acquired from Sigma Aldrich (St. Louis, MO, USA) with high purities (≥98%) as synthesis precursors. Dimethyl oxalate was purchased from Sigma Aldrich with purity ≥ 99% and was used for comparison with the self-synthesized one for validation of the synthesis procedure. 1-Pentanol was purchased by Roth GmbH (Karlsruhe, Germany) with purity ≥ 98%. The synthesis procedure was the same as reported by Ravotti et al. [18 (link)]; thus, concentrated sulfuric acid (H₂SO₄) was used as the acid catalyst (Sigma Aldrich, ≥99%), sodium sulfate anhydrous (Na₂SO₄) was used as a water-absorbing agent (Sigma Aldrich, ≥99%) for the elimination of water, and ethyl acetate (EtOAc) was used as the organic solvent for extraction (Sigma Aldrich, ≥99%). Cylohexane (Sigma Aldrich, GC quality, ≥99.9%) was used as the solvent for the Gas Chromatography coupled with Mass Spectrometry (GC-MS) analysis. All chemical materials listed above were used without any prior purification.