Thioglycolic acid

ZnSO₄, Na₂S, MnCl₂, and ethanol were supplied by Tianjin Guangfu Chemical Reagent Co. Ltd. (Tianjin, People’s Republic of China). N,N-dimethyl formamide was purchased from Tianjin Chemical Reagent Co. Ltd. (Tianjin, People’s Republic of China). 1-Ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride was supplied by Shanghai GL Biochem Reagent Co Ltd. (Shanghai, People’s Republic of China). Thioglycolic acid and glutaraldehyde were purchased from Sinopharm Chemical Reagent Co. Ltd. (Shanghai, People’s Republic of China). PEG with hydroxy-terminal (PEG, Mw 2,000) was purchased from Alfa aesar (Tianjin, People’s Republic of China). Dimethylaminopyridine was obtained from Sigma-Aldrich (St Louis, MO, USA). Normal saline (NS, 0.9%) was supplied by Double-crane Pharmaceutical Co. Ltd (Beijing, People’s Republic of China). Deionized water was prepared from EMD Millipore (Billerica, MA, USA). Other reagents used were of analytical grade.

Thioglycolic acid (TGA), CuCl₂·2H₂O, sodium hydroxide (NaOH), anhydrous ethanol (AR), 1-ethyl-3-[3-dimethylaminopropyl]carbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS) were bought from Sinopharm Chemical Reagent Co. (Shanghai, China). NIR fluorescence probe MBA (MW = 768) was synthesized in our laboratory. CRGD was obtained from Nanjing Peptide Industry Biotechnology Co. (Nanjing, China). Thioacetamide (TAA) were purchased from Aladdin (Shanghai, China). 3-(4,5-Dimethylthialzol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), DMEM medium, fetal bovine serum (FBS), penicillin, streptomycin, dimethyl sulfoxide (DMSO), trypsin–EDTA, bovine serum albumin (BSA), and Hoechst 33342 were purchased from Jiangsu Kaiji Biotechnology Co. (Jiangsu China). Ultrapure millipore water (18.2 MU) was used. All other solvents and reagents used in this study were certified analytical reagent grade.