Citric acid monohydrate

Iron sulfate heptahydrate (FeSO₄·7H₂O, ≥99.0%), anhydrous sodium sulfate (Na₂SO₄, ≥99.0%), ascorbic acid (C₆H₆O₆, ≥99.7%), and citric acid monohydrate (C₆H₁₀O₈, ≥99.5%) were bought from Sinopharm Chemical Reagent Co., Ltd. without further purification. Graphene oxide (GO) sheet powder was bought from Shenghui’s New carbon material store on the Taobao website. Ethylene carbonate (EC, 99.95%), propylene carbonate (PC, 99.99%), FEC (99.9%), and NaClO₄ salt (99.99%) was bought from the Aladdin website. Conductive carbon (super P, TIMICAL, >98.5% purity, D₅₀ = 40 nm), polyvinylidene fluoride (PVDF, Solvay5130), Whatman GF/D microfiber filter paper (~200-μm-thick, average pores size of 2.7 µm, Cytiva), Al foil (Al >99.999%, 20 µm), and copper foil (9 µm) were bought from Canrd New Energy Technology Co., Ltd. Na metal (99.7%) was bought from Beijing Yinokai Technology Co., Ltd.

Type A gelatin (from porcine skin), Tris(hydroxymethyl)aminomethane Hydrochloride (Tris-HCl), citric acid monohydrate, Iron(III) nitrate nonahydrate, nitric acid, sodium hydroxide, and sodium chloride were purchased from Sinopharm Chemical Reagent Co. Ltd. (Shanghai, China). PBS, MA, dopamine hydrochloride, and 2-Hydroxy-4′-(2-hydroxyethoxy)-2-methylpropiophenone (photoinitiator I2959) were supplied by Aladdin Scientific Corp. (Shanghai, China). The pancreatic stents (SPSOF-5-10, batch number C1783145) were obtained from Cook Ireland Limited (Limerick, Ireland). The pancreatic duct calculi were supplied by Changhai Hospital, Naval Military Medical University. The Cell Counting Kit (CCK-8, CK04, Lot. VG533) was obtained from Dojindo Laboratories (Kumamoto, Japan). The Calcein/PI Live/Dead Viability/Cytotoxicity Assay Kit (C2015M, Lot. 121522230328) was purchased from Beyotime Biotech. Inc. (Shanghai, China).

Waste cow leather (CL) was supplied by a local tannery in Zhejiang Province, China. Acetic acid (HAC), sodium hydrogen phosphate (Na₂HPO₄·12H₂O), citric acid monohydrate (C₄H₂O₇·H₂O), Sodium hypochlorite (NaClO), and absolute ethanol were purchased from Sinopharm Chemical Reagent Co. Ltd., Shanghai, China. The RR120, RY167, and RB222 dyes were kindly supplied by Luthai Textile Co. Ltd., Shandong, China, and the chemical structures of the dyes are shown in Figure 1. Deionized water was employed throughout the experiments. All chemicals were of analytical grade and used as received.

All the chemicals are of analytical reagent grade and used without further purification. Citric acid monohydrate, ethylenediamine, dimethylsulfoxide (DMSO), copper chlorophyllin, 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC), N-hydroxysulfosuccinimide sodium salt (S-NHS), ethanol and silver nitrate (AgNO₃) were purchased from Sinopharm Chemical Reagent Co. Ltd.
The UV-Vis absorptions were measured with a Cary-60 UV-Vis spectrophotometer (Agilent, USA). The FL spectra of the samples in quartz cells were measured on a Cary Eclipse fluorescence spectrophotometer (Agilent, USA) using a Xe lamp as the excitation source in the same condition of measurements. The transmission electron microscope (TEM) images were captured on a Tecnai F30 instrument (FEI, USA). The X-ray powder diffraction (XRD) analysis was performed on an AXS-D2 diffractometer (Bruker, Germany) with Cu Kα radiation (λ = 1.5406 Å). The Cu²⁺ content in CCPh-CDs was measured by an Agilent-7900cx inductively coupled plasma mass spectrometer (ICP-MS). The decay lifetimes of the samples were measured at room temperature using an FLS920 lifetime spectrofluorophotometer.

Most of the chemicals were purchased from the following manufacturers: Aladdin (PrCl₃, 99.9%; TbCl₃·6H₂O, 99.9%; HoCl₃·6H₂O, 99.9%; LuCl₃·6H₂O, 99.9%; citric acid monohydrate, 99.5%; trimethylsilycyanide, 96%), Energy chemical [NdCl₃·6H₂O, 99.99%; SmCl₃·6H₂O, 99.99%; EuCl₃·6H₂O, 99.99%; GdCl₃·6H₂O, 99.99%; DyCl₃·6H₂O, 99.99%; ErCl₃·6H₂O, 99.99%; TmCl₃·6H₂O, 99.99%; dimethylamine hydrochloride, 98%; α-(trimethylsilyloxy)phenylacetonitrile, 97%], Alfa Aesar (YbCl₃·6H₂O, 99.9%), and Sinopharm Chemical Reagent Co., Ltd. (Na₂WO₄·2H₂O, AR; LaCl₃·nH₂O, AR; CeCl₃·6H₂O, 99%; benzaldehyde, AR; acetophenone, AR). These reagents were used without further purification, except benzaldehyde. The Anderson-type tungstotellurates(VI), Na₆TeW₆O₂₄·22H₂O, was prepared according to the literature (Shah et al., 2014 (link)).

Ferric trichloride, sodium acetate, citric acid monohydrate, diethylenetriamine, N-(3-dimethylaminopropyl)-Nethylcarbodiimide hydrochloride (EDC), N-hydroxysuccinimide (NHS), 4-aminobutyric acid (GABA) and o-phenylenediamine (OPD) were purchased from Sinopharm Chemical Reagent Co., Ltd. (Shanghai, China). Recombinant Protein Tyrosine Kinase 7 (PTK 7) was obtained from Wuhan USCN Business Co., Ltd. (Wuhan, China). The base sequences of the DNA oligonucleotides were provided as follows: aptamer of PTK7 (APT, ATC TAA CTG CTG CGC CGC CGG GAA AAT ACT GTA CGG TTA GA), cDNA (complementary to part of the PTK7 aptamer, TCT AAC CGT ACA GTA TTT TCC CGG CGG CG), and all of them were purchased from Shanghai Sangon Biotechnology Co., Ltd. (Shanghai, China). E. coli exonuclease I (DNase I, > 10 U μL⁻¹) was also provided by Shanghai Sangon Biotechnology. The purified water was prepared using a water purification system that was obtained from the Thermo Scientific technology Co., Ltd. (Shanghai, China). All other chemicals that did not have special specifications but were used in this paper were of analytical grade and used without further purification.