▎ 摘　　要

NOVELTY - Fabricating graphene oxide-based immunochip involves mixing 0.62 g powdered graphite with 0.47 g sodium nitrate, adding 45 mL concentrated sulfuric acid gradually in flask at room temperature with the constant stirring, adding 1.88 g potassium permanganate in small increments with great care, and stirring continuously for 5 days, adding 5 wt.% sulfuric acid, heating to 98 °C for 2 hours followed by cooling to 60 °C, adding 30 wt.% hydrogen peroxide, keeping solution for 2 hours at 98 °C, centrifuging for 30 minutes to pellet down the nanoparticles, washing the pellet with 5% solution of sulfuric acid followed by washing with 5% solution of hydrochloric acid and distilled water until supernatant's pH reached neutrality. USE - Method for fabricating graphene oxide-based immunochip for detection of vitamin D3. No biological data given. ADVANTAGE - The developed immunosensor shows a sensitivity of 0.36 mA/mm2/pg and limit of detection 30.93 pg/microliters for electrochemical detection of vitamin D3. DETAILED DESCRIPTION - Fabricating graphene oxide-based immunochip involves mixing 0.62g powdered graphite with 0.47 g sodium nitrate, adding 45 mL concentrated sulfuric acid gradually in flask at room temperature with the constant stirring, adding 1.88 g potassium permanganate in small increments with great care, and stirring continuously for 5 days, adding 5 wt.% sulfuric acid, heating to 98 °C for 2 hours followed by cooling to 60 °C, adding 30 wt.% hydrogen peroxide, keeping solution for 2 hours at 98 °C, centrifuging for 30 minutes to pellet down the nanoparticles, washing the pellet with 5% solution of sulfuric acid followed by washing with 5% solution of hydrochloric acid and distilled water until supernatant's pH reached neutrality, drying the pellet of nanoparticles overnight in an oven to obtain the powdered graphene oxide nanoparticles (GONPs), cleaning the working electrode using 70% ethanol and distilled water to eliminate adsorbed contaminants, prior to drop-casting, preparing a solution of graphene oxide in ethanol and drop-casting onto electrode surface, followed by drying at room temperature, subjecting the modified SPPE to 25-hydroxyvitamin D3 antibody incubation, treating with 6 microliters of 10mM 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide:N-hydroxysuccinimide in the ratio of 1:1 primed in phosphate-buffered saline buffer solution (pH 7.2) and specifying onto the working electrode and later, washing with phosphate-buffered saline buffer, adding anti-25-hydroxyvitamin D3, and carrying out overnight incubation in a humid chamber, washing electrode multiple times with buffer solution, followed by the addition of 0.1 mg/mL bovine serum albumin for 60 minutes, and washing the electrode again with buffer solution.