Nanoheterojunction-Mediated Thermoelectric Strategy for Cancer Surgical Adjuvant Treatment and β-Elemene Combination Therapy

As an indispensable strategy for tumor treatment, surgery may cause two major challenges: tumor recurrence and wound infection. Here, a thermoelectric therapeutic strategy is provided as either an independent cancer therapy or surgical adjuvant treatment. Bi_0.5 Sb_1.5 Te₃ (BST) and Bi₂ Te_2.8 Se_0.2 (BTS) nanoplates composed of Z-scheme thermoelectric heterojunction (BST/BTS) are fabricated via a two-step hydrothermal processes. The contact between BST and BTS constructs an interfacial electric field due to Fermi energy level rearrangement, guiding electrons in the conductive band (CB) of BTS combine with the holes in the valance band (VB) of BST, leaving stronger reduction/oxidation potentials of electrons and holes in the CB of BST and the VB of BTS. Moreover, under a mild temperature gradient, another self-built-in electric field is formed facilitating the migration of electrons and holes to their surfaces. Based on the PEGylated BST/BTS heterojunction, a novel thermoelectric therapy platform is developed through intravenous injection of BST/BTS and external cooling of the tumors. This thermoelectric strategy is also proved effective for combination cancer therapy with β-elemene. Moreover, the combination of heterojunction and hydrogel is administrated on the wound after surgery, achieving efficient residual tumor treatment and antibacterial effects.