▎ 摘　　要

NOVELTY - Preparing heterojunction photothermal reagent comprises (a) dispersing tungsten sulfide powder in an excess sulfuric acid solution and reacting, centrifuging reaction solution and washing the collected product with deionized water to remove residual sulfuric acid and dispersing washed product in deionized water for ultrasonic treatment and (b) adding 1,3,6-trinitroguanidine and polyethyleneimine to water and mixing evenly, heating the mixed suspension, cooling, filtering cooled suspension by microporous membrane to remove insoluble residues and dialyzing the obtained filtrate against dialysis bag and (c) stirring the tungsten sulfide nanosheet prepared in the step (a) and near-infrared two-region-responsive graphene quantum dot prepared in the step (b) vigorously in phosphate buffered saline solution, centrifuging mixture to remove unbound graphene quantum dots to obtain the near-infrared two-region response graphene quantum dot/sulfur tungsten heterojunction photothermal reagent. USE - The reagent is useful for preparing a medicine for photothermal therapy of osteosarcoma and for promoting osteogenic differentiation of mesenchymal stem cells (claimed). ADVANTAGE - The reagent: has high biocompatibility, no toxicity and no pollution. The method is simple, economical, suitable for scale production and clinical medical use. DETAILED DESCRIPTION - Preparing heterojunction photothermal reagent comprises (a) preparing tungsten sulfide nanosheets by, (a.1) dispersing tungsten sulfide powder in an excess sulfuric acid solution and reacting at 80-100 degrees C for 15-30 hours, (a.2) centrifuging the reaction solution and washing the collected product with deionized water to remove residual sulfuric acid and dispersing the washed product in deionized water for ultrasonic treatment for 1-3 hours and centrifuging the dispersion and collecting tungsten sulfide nanosheets and (a.3) dispersing the collected tungsten sulfide nanosheets in 20 ml deionized water, (b) preparing near-infrared two-region response graphene quantum dots by (b.1) adding 1,3,6-trinitroguanidine and polyethyleneimine to water and mixing evenly, (b.2) heating the mixed suspension at 220-250 degrees C for 5 minutes, cooling to room temperature, (b.2) filtering the cooled suspension by microporous membrane to remove insoluble residues and (b.3) dialyzing the obtained filtrate against dialysis bag having a molecular weight of 3500 for two days to obtain a near-infrared two-region response graphene quantum dot and (c) preparing of near-infrared two-zone response graphene quantum dots/tungsten sulfide heterojunction by (c.1) stirring the tungsten sulfide nanosheet prepared in the step (a) and the near-infrared two-region-responsive graphene quantum dot prepared in the step (b) vigorously in phosphate buffered saline solution (pH=8.0) for 24 hours, depositing the responsive graphene quantum dots on the surface of the tungsten sulfide nanosheet, (c.2) centrifuging the mixture to remove the unbound graphene quantum dots to obtain the near-infrared two-region response graphene quantum dot/sulfur tungsten heterojunction photothermal reagent.