Succinic anhydride 99

Silver nitrate (AgNO₃), sodium borohydride (NaBH₄), succinic anhydride 99% (C₄H₄O₃), and N, N-diisopropylethylamine (DIPEA) were acquired from Acros Organics (Morris, NJ, USA). Ammonium hydroxide solution 30% (NH₄OH) was purchased from Honeywell Fluka^TM (Loughborough, UK). Gold (III) chloride trihydrate (HAuCl₄·3H₂O) was purchased from Alfa Aesar (Haverhill, MA, USA). D-glucose, sodium hydroxide (NaOH), dimethylformamide (DMF, 99.5%), SYTOX green, and polysine substrates (2.5 cm × 7.5 cm × 0.1 cm) were purchased from Thermo Fisher Scientific (Waltham, MA, USA). Hoechst 33342 was purchased from Bio-genesis Technologies, Inc. (Taipei, Taiwan). Paraformaldehyde (PFA) was purchased from Sigma-Aldrich (St. Louis, MO, USA). Trypticase Soy Broth (TSB) Medium was purchased from Condalab (Madrid, Spain).

Betulin disuccinate (obtained in the laboratory according to the procedure described earlier [10 (link)]), succinic anhydride 99% (ACROS Organics, Geel, Belgium), toluene (STANLAB, Lublin, Poland), acetic anhydride (POCh S.A., Gliwice, Poland), glycerol ethoxylate (average M_n~1000) (Sigma Aldrich, St. Louis, MO, USA), DMSO (Chempur, Piekary Śl., Poland), trichloroacetic acid (Chempur, Piekary Śl., Poland), acetic acid (Chempur, Piekary Śl., Poland), Tris buffer, sulforhodamine, tetrahydrofuran (Chempur, Piekary Śl., Poland), and methylene chloride (Chempur, Piekary Śl., Poland) were used as supplied.