▎ 摘　　要

NOVELTY - Preparing small interfering RNA (siRNA) targeting pH-responsive drug-loaded photothermotherapy nanoparticles by (a) selecting graphene quantum dot and doxorubicin hydrochloride, (b) dissolving polylactic acid-glycolic acid copolymer in dichloroethylene, (c) dissolving water-soluble carboxymethyl chitosan in water, (d) dissolving small interfering siRNA in a phosphate buffer solution, (e) mixing graphene quantum dot and doxorubicin hydrochloride, adding PLGA organic solution and ultrasonically emulsifying solution, (f) transferring W/O initial emulsion to carboxymethyl chitosan and ultrasonically treating, (g) adding deionized water, magnetically stirring, centrifuging, collecting microparticles, washing with deionized water and lyophilizing nanoparticles, (h) dispersing nanoparticles in phosphate buffer and stirring well, (i) adding homogeneous solution to dispersion, stirring material and (j) centrifuging solution, washing cells with phosphate buffer and collecting microparticles. USE - The method is useful for preparing siRNA targeting pH-responsive drug-loaded photothermotherapy nanoparticles. ADVANTAGE - The polymer nanoparticles prolongs the release of drug and increases the stability of polymer particles, enhances the treatment of cancer cells and does not have significant impact on cells in the later experimental process, and is non-toxic and environmentally-friendly. DETAILED DESCRIPTION - Method for preparing small interfering RNA (siRNA) targeting pH-responsive drug-loaded photothermotherapy nanoparticles involves (a) selecting 1 mg/ml graphene quantum dot and anticancer drug aqueous solution of doxorubicin hydrochloride and pre-cooling at 4 degrees C, (b) dissolving polylactic acid-glycolic acid (PLGA) copolymer in dichloroethylene to prepare a PLGA organic solution having a concentration of 2-4%, preferably 3%, and pre-cooling at 4 degrees C, (c) dissolving water-soluble carboxymethyl chitosan in water to prepare a carboxymethyl chitosan aqueous solution having a concentration of 3-5%, preferably 4%, and pre-cooling at 4 degrees C, (d) dissolving small interfering siRNA in a phosphate buffer solution to prepare uniform solution having a concentration of 20-40 mu mol/l, preferably 30 mu mol/l, and pre-cooling at 4 degrees C, (e) mixing 1-2 ml, preferably 1.5 ml graphene quantum dot aqueous solution and 1-2 ml, preferably 1.5 ml anticancer drug aqueous solution of doxorubicin hydrochloride, adding 8-12 ml, preferably 10 ml PLGA organic solution and ultrasonically emulsifying at amplitude of 30 for 1-2 minutes, preferably 1.5 ml to prepare water-in-oil (W/O) primary emulsion, (f) transferring the W/O initial emulsion to 18-24 ml, preferably 21 ml aqueous solution of carboxymethyl chitosan, and ultrasonically treating for 1-2 minutes, preferably 1.5 minutes to prepare water-in-oil-in water (W/O/W) multiple emulsion, (g) adding 60-80 ml, preferably 70 ml deionized water to W/O/W double emulsion in dropwise, magnetically stirring, aging for 30-60 minutes, preferably 45 minutes, evaporating, centrifuging at 14000 revolutions per minute for 5-10 minutes, preferably 7.5 minutes, collecting the microparticles, washing 2-3 times, preferably 2 times with deionized water to remove residual dispersant, and finally freeze-preserving nanoparticles, (h) dispersing 40-50 mg, preferably 45 mg nanoparticles in 40-50 ml, preferably 45 ml phosphate buffer and stirring well, (i) taking 10-20 ml, preferably 15 ml homogeneous solution, adding dropwise to dispersion obtained in step (h) at room temperature, stirring evenly for 2 hours and standing for 20-30 minutes, preferably 25 minutes and (j) centrifuging the solution at 14000 revolutions per minute for 5-10 minutes, preferably 7.5 minutes, washing the cells for 2-3 times with phosphate buffer, and collecting the microparticles.