Brain heart infusion agar

Titanium(IV) isopropoxide (TTIP, Sigma–Aldrich, St. Louis, MO, USA, 97%) and anatase TiO₂ powder were purchased from Sigma–Aldrich Chemicals (St. Louis, MO, USA). HCl (35–38 wt.%), H₂SO₄ (96 wt.%), AgNO₃, SnCl₂, ammonia solution (25%), NaOH, Na₂HPO₄, and KH₂PO₄ were purchased from Avantor Performance Materials (Gliwice, Poland). NaBH₄ was supplied by Merck, (Darmstadt, Germany). 2-propanol, KCl, and NaCl were provided by Chempur (Piekary Śląskie, Poland).
Microbiological tests were carried out using Plate Count Agar (PCA) and Brain Heart Infusion (BHI) Agar (BIOMAXIMA, Lublin, Poland). Gram-negative Escherichia coli (strain K12, ATCC 29425, Manassas, VA, USA) and Gram-positive Staphylococcus epidermidis (ATCC 49461, Manassas, VA, USA) were used as model microorganisms. The initial concentration of bacteria suspension was set at 0.5 using McFarland scale (McFarland standards, bioMérieux, Marcy-l’Étoile, France).
In all experiments, pure (deionized) water (type 2, 0.066 µS cm⁻¹) from Elix 3 (Millipore, Burlington, MA, USA) was used, unless otherwise stated.

CSA-13, CSA-44, CSA-131, and CSA-255 were synthesized as described previously [67 (link)]. Cathelicidin LL-37 and omiganan were synthetized by Lipopharm.pl (Zblewo, Poland). Reagents for colorimetric, fluorescent-based, and microscopic analyses, namely, resazurin sodium salt, Hoechst 33342, and thiazolyl blue tetrazolium bromide (MTT) were purchased from Sigma Aldrich (St. Louis, MO, USA). Fluorescent-labeled phalloidin was from ThermoFisher Scientific (Waltham, MA, USA). Culture media, including Sabouraud 4% dextrose agar, Columbia agar +5% sheep blood, Brain Heart Infusion (BHI) agar, and Tryptic Soy Broth (TSB) were obtained from BioMaxima (Lublin, Poland). The VITEK 2R Fungal Susceptibility Cards (AST-YS07) were acquired from bioMerieux (Marcy-l’Etoile, France). Commercially available mouthwashes containing chlorhexidine digluconate, cetylpyridinium chloride, octenidine, or essential oils (with or without alcohol), were used to compare the antimicrobial activity of ceragenins to conventional products.