N 3 dimethylaminopropyl n ethylcarbodiimide hydrochloride edc

First, 2 g gelatin was dissolved in 200 mL Morpholine ethanesulfonic acid (MES, J&K Scientific) solution (0.5 w/v%, pH 6.5). Then, 2.3012 g of Adipic acid dihydrazide (ADH, J&K Scientific) was added to the gelatin solution and stirred at 37 °C or 2 h. After returning to room temperature, 0.5066 g of N-(3-Dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (EDC, J&K Scientific) and 0.357 g of 1-Hydroxybenzotriazole (HOBT, J&K Scientific) was added to the solution and stirred at room temperature for 22 h. The resulting solution was purified by dialysis (MWCO 8–14 kDa) against DI water for five days. Then, the dialyzed solution was freeze dried under vacuum to obtain yield purified product Gel-ADH.

All reagents were commercially available. MNPs were synthesized by Materials Science and Engineering Laboratory at Southeast University (Nanjing, China). The manufacturer details of the reagents are listed as follows: EMO was purchased from Shanghai YuanYe Biotechnology Ltd (Shanghai, China); Cy7-NHS ester, N-(3-dimethylaminopropyl)-N-ethylcarbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS) were purchased from J&K Chemical Ltd (Shanghai, China). Dimethyl sulfoxide (DMSO), Annexin V-fluorescein isothiocyanate (FITC)/propidium iodide (PI) apoptosis detection agents and Matrigel, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) were purchased from Sangon Biological Engineering Technology & Services Ltd (Shanghai, China). Bovine serum albumin (BSA) was purchased from Sigma-Aldrich (MO, USA); Human pancreatic cell line BxPC-3 was purchased from the Chinese Academy of Sciences Shanghai Branch Cell Bank (Shanghai, China); The hTERT-HPNE (Human Pancreatic Nestin Expressing) cell line was purchased from Shanghai BoQuaner Biological Science and Technology Ltd (Shanghai, China).