Graphene oxide

The MUC1, EpCAM, BSA, PSA and VEGF were purchased from Cusabio Biotech Co. Ltd. (http://www.cusabio.cn/). Graphene oxide was purchased from XFNANO Co. Ltd. (Nanjing, China, http://www.xfnano.com). The deoxyribonuclease I (DNase I) were obtained from solarbio (Beijing, China, http://www.solarbio.com). The MUC1 (5′-FAM-CCCGTCTTCCAGACAAGAGTGCAGGG-3′) aptamer were synthesized by Sangon Biological Engineering Technology Co., Ltd. (Shanghai, China, http://www.sangon.com) and purified using high performance liquid chromatography. All of the reagents were diluted to the required concentration with working buffer (10 mM Tris, 100 mM NaNO₃ pH 7.4) before usage. Healthy human serum, urine and saliva were provided by Affiliated Dongfeng Hospital, Hubei University of Medicine, and approved by Hospital's Ethics Committee. The other reagents employed were of analytical grade and used without further purification. Ultrapure water obtained from a Millipore water purification system (18.2 MΩ cm resistivity, Milli-Q Direct 8) was used in all runs.

Graphene oxide (GO, made from graphite flake, GO’, small flakes and dry platelets) was obtained from XF NANO, INC and graphene supermarket, respectively. Hydrazine monohydrate (N₂H₄·H₂O, 80%) was purchased from Guangdong Guanghua Sci-Tech Co., Ltd (JHD). (NH₄)₂MoS₄, Polypyrrole (PPy,) and Pt/C (10% Pt) were obtained from Sigma-Aldrich. N, N-dimethylformamide (DMF, ≥99.5%) and KOH were purchased from Sinopharm Chemical Reagent Co., Ltd. Sulfuric acid (H₂SO₄, 95–98%) and ethanol (99.9%) was acquired from Beijing Chemical Works. All aqueous solutions were prepared with doubly distilled water.

Graphene oxide (GO, thickness, 0.8–1.2 nm) was purchased from Nanjing XFNANO Materials Tech. Co., Ltd and employed as the support. 1,10-Phenanthroline(C₁₂H₈N₂, 97.0%), Zeolite (Permutit) and γ-Al₂O₃ were all purchased from Aladdin. Carbon black VX 72 was bought from Cabot Corporation. Acetone, Cobalt(II) chloride hexahydrate (CoCl₂·6H₂O, 99.0%), Copper(II) chloride dihydrate (CuCl₂·2H₂O, 99.0%), Manganese(II) chloride tetrahydrate (MnCl₂·4H₂O, 99.0%), and Palladium(II) chloride (PdCl₂, 99.99%) were received from Sinopharm Chemical Reagent Co., Ltd. Rhodium(III) chloride trihydrate (RhCl₃·3H₂O, 98%), Chloroauric acid (HAuCl₄), and Chloroplatinic acid hexahydrate (H₂PtCl6·6H₂O, 99.99%) were purchased from Shanghai Macklin Biochemical Co., Ltd. Nickel chloride hexahydrate (NiCl₂·6H₂O, 99.999%), Stannic chloride hydrated (SnCl₄·5H₂O, 99.995%), and Iridium chloride (IrCl₃, 99.8%) were received from Aladdin. All the reagents were used without further purification. Ultrapure Milli-Q water (18.2 MΩ cm⁻¹) was used to prepare all the aqueous solutions and wash samples. Ethanol was received from Shanghai Lingfeng chemical regent Co., Ltd. Pt/C (20 wt%) was purchased from MACKLIN Biochemical Technology Co., Ltd.

All oligonucleotides used in this work (Table S1) were synthesized with high-performance liquid chromatography (HPLC) purification by hippo Biotech. Co., Ltd. (Zhejiang, China), which DNA with adasic sites was synthesized by Sangon Biotech. Co., Ltd. (Shanghai, China). Graphene oxide was obtained from XFNANO Materials Tech Co., LTD. (Nanjing, China) without any modification. All solutions were prepared with Milli-Q water (18.2 MΩ·cm) from a Milli-Q purification system (Millipore).

Sn2.5Ag0.5Cu0.1RE alloy powders (diameter 25–45 μm, TITD, Changsha, China) were used as matrix solder. The GNSs were produced via chemical reduction of graphene oxide (diameter 5–15 μm, thickness 5–25 nm, XFNANO, Nanjing, China) by hydrazine hydrate [23 (link)].

Graphene oxide was purchased from Nanjing XFNANO Materials Tech Co., Ltd., Nanjing, China. MAI and PbI₂ were purchased from Xi’an Polymer Light Technology Corporation, Xi’an, China. DMF and DMSO were purchased from Alfa Aesar, Shanghai, China and TiO₂ 10% soluble in ethanol (particle size ~30 nm) were purchased from InnoChem, Beijing, China. All prescribed materials were used as is (i.e., without any extra purification). Glass slides manufactured by SAIL BRAND, Hangzhou, China were used as substrate after three-step cleaning.