Response surface methodology for the synthesis of an Auricularia auriculajudae polysaccharides-CDDP complex

A self-assembly method was used to synthesize the Auricularia auriculajudae polysaccharides (AAPs)-cisplatin (cis-dichlorodiammine platinum (II), CDDP) complexes. Response surface methodology (RSM) was used to optimize the synthesis conditions. The effects of four independent factors: pH (X₁: 1-9), time (X₂: 0.5-3h), temperature (X₃: 20-70°C), and amount of CDDP (X₄: 2-22mg) on the platinum content in AAPs-CDDP complexes were evaluated. The RSM results showed that the optimal synthesis conditions were: X₁: 7.7, X₂: 1.83h, X₃: 56.93°C, and X₄: 6.02mg. Verification tests showed no significant differences between the practical and the predictive values for each response. Under the optimal conditions, platinum content was 47.0mg/g, without significant differences with the predicted value (47.1mg/g). The FT-IR analysis and ¹H NMR spectra of AAPs-CDDP complexes showed that the AAPs combined with CDDP using the hydroxyl group on the polysaccharide's chains. In addition, the microphotograph of the AAPs and AAPs-CDDP complexes suggested that an AAPs-CDDP complex was formed. The MTT assay in vitro indicated that AAPs-CDDP complexes exhibited significant anti-tumor activity against Hela and LoVo cells.