Sodium borohydride

Gold chloride trihydrate (HAuCl₄∙3H₂O), sodium borohydride (NaBH₄), chlorhydric acid (HCl), nitric acid (HNO₃), sodium chloride (NaCl), basic fuchsine (pararosaniline hydrochloride) and sodium metabisulfite were purchased from VWR International. Polyethylene glycol dithiol with a molecular weight of 1000 g.mol⁻¹ (referred to as PEG double thiol) and periodic acid were purchased from Sigma-Aldrich (St. Louis, MO). Polyethylene glycol methyl ether thiol with a molecular weight of 2000 g.mol⁻¹ (referred to as PEG 2000) was purchased from Laysan Bio (Arab, AL). Dichloromethane and methanol were purchased from Fisher Scientific, and mucins from bovine submaxillary gland were purchased from Cedarlane Laboratories (Burlington, ON). All the glassware used for the synthesis of AuNP was first thoroughly washed with aqua regia (3:1 HCl:HNO₃) and rinsed with nanopure water.

Silver nitrate, lysozyme (from chicken egg white, approximately 100,000 units/mg), sodium chloride, and sodium hydroxide were purchased from Sigma-Aldrich (St. Louis, MO, USA). Sodium borohydride was purchased from VWR International Limited (BDH Merck Limited, Poole Dorset, UK). Tryptone, yeast extract, and agar were purchased from MP Biomedicals (Solon, OH, USA). The pure microbial strains were collected from local hospital and were identified by biochemical tests. LB was used as growth media for cultivating microbial strains and consisted of 0.5% yeast extract and 1% tryptone and sodium chloride in water having a pH of 7. Ultrapure water with a resistivity of 18.2 MΩ cm was used as solvent in all preparations.

Berberine chloride hydrate (14050), potassium carbonate (P5833), sodium hydroxide (S8045) and chloroform (650498) were purchased from Sigma Aldrich. Pharmaceutical compounding grade isopropyl myristate (8170662500) and polysorbate-20 (8170721000) were purchased from EMD-Millipore. Simvastatin (SIM, S485000), simvastatin hydroxy acid (SHA, S485020), d₆-simvastatin (d6-SIM, S485002), d₆-simvastatin hydroxy acid (d6-SHA, S485022), and d₆-berberine hydrochloride (d6-BBR, B318152) were purchased from Toronto Research Chemicals. Methanol (MX0488-1), water (Millipore-HPLC grade), and sodium borohydride (71321) were purchased from VWR. The transdermal base cream DelivraSR (13750–2) is manufactured by Delivra Corp. and is available commercially for compounding purposes.

2 nm AuNPs were prepared using a method adapted from Brust et al.39 (link). Deionized (DI) water (resistivity 15 MΩcm) was used in all experiments. An aqueous solution of chloroauric acid trihydrate (VWR, UK) (6 mL, 30 mM) was mixed with tetraoctylammonium bromide (Sigma Aldrich, UK) (16 mL, 50 mM) in toluene (Fisher Scientific, UK). The mixture was vigorously stirred until the gold salt was completely transferred to the organic phase and 1-dodecanethiol (DDT) (Sigma Aldrich) (34 mg) was added. Freshly, prepared aqueous sodium borohydride (VWR, UK) (5 mL, 0.4 mM) was added dropwise and the solution was continuously stirred over a period of 3 h. The organic layer was subsequently extracted and evaporated to 2 mL. ethanol (80 mL) was added to the organic layer and stored for 4 h at −18 °C, after which the black precipitate was filtered off and washed with ethanol (Merck Millipore, UK). The freshly made nanoparticles were subsequently suspended in toluene for further use.

All phenolic acid standards, Trolox, 2,2-diphenyl−1-picrylhydrazyl radical (DPPH^•), 2,2′-azino-bis-3(ethylbenzthiazoline-6-sulphonic acid) (ABTS^•+), soybean 15-lipooxygenase, xanthine oxidase, linoleic acid, allopurinol, quercetin, α-glucosidase, p-nitrophenyl-α-D-glucopyranoside, α-amylase, starch solution, dinitrosalicylic acid, Rochelle salt, and acarbose were provided by Sigma-Aldrich Chemical Co. (St. Louis, MO, USA). Methanol, ethanol, chloroform, diethyl ether, sodium bicarbonate, hydrogen chloride, anhydrous sodium sulphate, sodium borohydride, sulphuric acid, sodium carbonate, sodium hydroxide, and phosphate buffer were purchased from Avantor Performance Materials Poland (Gliwice, Poland). All the chemicals were of analytical grade. LC grade Methanol and formic acid were purchased from J.T. Baker (Phillipsburg, NJ, USA). LC grade water was prepared using a Millipore Direct-Q3 purification system (Bedford, MA, USA).