▎ 摘　　要

NOVELTY - Method for synthesizing performing reduced graphene oxide (rGO) silica (SiO2) nanocomposite, involves mixing soot of Nigella sativa in an acid, adding first oxidant into the solution and stirring first suspension, adding N.sativa seed extract and second oxidant, isolating the formed reduced graphene oxide nanoparticles, suspending the reduced graphene oxide nanoparticles in water, ultrasonicating and centrifuging the second suspension, adding solution containing tetraethyl orthosilicate, and isolating the reduced nanocomposite. USE - The method is useful for synthesizing reduced graphene oxide silica nanocomposite, which is used to inhibit growth or proliferation of cancer cell, preferably breast carcinoma cell (all claimed). ADVANTAGE - The method enables to synthesize reduced graphene oxide silica nanocomposite in a environmentally-friendly manner. DETAILED DESCRIPTION - Method for synthesizing reduced graphene oxide (rGO) silica (SiO2) nanocomposite, involves (a) mixing quantity of soot of Nigella sativa in an acid while stirring to obtain a solution, (b) adding first oxidant gradually into the solution to oxidize the soot and obtain first suspension, (c) stirring the first suspension while maintaining a temperature of suspension at 35 degrees C, (d) adding N.sativa seed extract to the first suspension while raising the temperature of suspension to 60 degrees C, (e) adding second oxidant to the suspension to form reduced graphene oxide nanoparticles, (f) isolating the formed reduced graphene oxide nanoparticles by centrifugation, (g) suspending the reduced graphene oxide nanoparticles in water to form a second suspension, (h) ultrasonicating the second suspension for 60 minutes, (i) centrifuging the second suspension at 3000 revolutions per minute (rpm) to remove any aggregates, (i) adding solution comprising tetraethyl orthosilicate (TEOS), concentrated aqueous ammonia solution and N.sativa seed extract under ultrasonication conditions to obtain a third suspension, (j) increasing the temperature of third suspension to 90 degrees C while stirring gradually for 3 hours to form reduced graphene oxide-silicon dioxide nanocomposite suspension, and (k) isolating the reduced graphene oxide-silicon dioxide nanocomposite by filtration. An INDEPENDENT CLAIM is included for reduced graphene oxide silica nanocomposite produced by the method.