Sulfo n hydroxysulfosuccinimide sulfo nhs

MccJ25 containing 21 amino acids was provided by our research team, Prof. Qiao’s lab. The peptide was prepared as previously described [28 (link)]; the sequence and molecular weight were GGAGHVPEYFVGIGTPISFYG and 2107 Da. Purified MccJ25 was 99.96%. The conjugation of CNs–MccJ25 (CNMs) was performed as follows: CNs were dissolved in 0.1 M sodium acetate (Thermo Fisher Scientific Inc., Waltham, MA, USA) buffer (pH 5.5) to 1% (w/v). MccJ25 was added to the solution (CN:MccJ25 ratio = 10:1, w/w). Then, 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC; 0.5 mM; Sigma-Aldrich, St. Louis, MO, USA) and sulfo-N-hydroxysulfosuccinimide (sulfo-NHS; 0.25 mM; Sigma-Aldrich, St. Louis, MO, USA) were immediately added to the mixture, stirred at 4 °C and left overnight. Conjugators, CNMs, were permeabilized by Mill-Q water (dialysis membrane molecular weight cutoff 12–14 kDa). Equal volumes of water were replaced every 1 h until 24 h. After dialysis, CNMs were freeze-dried overnight. CNMs lyophilized powder was dissolved in sterile Mill-Q water and stored at 4 °C until assayed [24 (link)].

1-Ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC, ≥99%), sulfo-N-hydroxysulfosuccinimide (sulfo-NHS, ≥98.5%), and SWCNTs were purchased from Sigma Aldrich. Ochratoxin A (OTA), Deoxynivalenol (DON), Fumonisin B1 (FB1), Patulin, Warfarin, Aflatoxin B1 and G1 from Aspergillus flavus ≥ 98.00% (HPLC), and Aflatoxins B2 and G2 ≥ 98.00% (TLC) standards were purchased from Sigma-Aldrich. Ochratoxin B (OTB) was purchased from Santa Cruz Biotechnology Canada. Carboxyl QDs 525 (Green CdSe/ZnS) and Carboxyl QD 655 (Red CdSeTe) were purchased from Life Technologies (Thermo Fisher Scientific), Burlington, ON Canada. All buffers were prepared with Millipore Milli-Q deionized water at 18 MΩ. All molecular biology grade electrophoresis chemicals were purchased from BioShop Canada (Burlington, Ontario). Reference samples (wheat, barley, corn, oats and malted barley) were provided from Trilogy Analytical laboratory. 5′NH₂ - modified A08min and 1.12.2 aptamers were purchased from Integrated DNA Technologies (IDT).