High-energy ionizing radiation brings serious challenges to medical professionals, and it demands efficient and lightweight shielding materials depending on high-Z elements and structural supporting matrices. Herein, we have integrated multiple high-Z elements and multilayer structures into composite films with interlayer scattering effects for constructing high-energy X-ray shielding clothes. A series of composite films containing different combinations of X-ray shielding particles (SnO 2 , BaSO 4 , and Bi 2 O 3 ) were prepared in tightly connected two layers with each layer consisting of corresponding hybrid polyacrylonitrile (PAN) fibers-reinforced hybrid thermoplastic polyurethane (TPU) coating. The optimized composite film L Ba3.7 /L Bi3.7 avoids lead toxicity and has a tensile strength of 17.92 MPa and high flexibility due to the reinforcing effect of PAN hybrid fibers. The L Ba3.7 /L Bi3.7 with a density of ∼ 2.98 g cm −3 and a thickness of 2.24 mm exhibits 18 % lighter than the 0.5 mmPb lead apron. Owing to the combination of multiple particles and layer structures, the absorption and interlayer scattering effects of L Ba3.7 /L Bi3.7 are leveraged to confer a high X-ray shielding efficiency of 96.3 % at 100 keV, surpassing single-element films and closing to 0.5 mmPb lead apron. This work offers a viable strategy for developing flexible, lightweight, and efficient wearable materials for high-energy X-ray shielding.
Radiotherapy, as well as chemotherapy and surgery, occupies an essential position in tumor treatment. Nonetheless, insufficient radiation deposition and hypoxia-related radioresistance of cancer cells still are serious challenges in radiotherapy. Herein, we proposed a hollow PtCo nanosphere (PtCo NS)-based novel radiosensitizer with three advantages to sensitize tumor radiotherapy: (i) the high-Z element Pt ensured higher radiation absorption to cause more DNA damage, (ii) the platinum (Pt) and cobalt (Co) elements exhibited a dual catalase-like enzymatic activity to convert endogenic H2O2 to O2 efficiently, and (iii) the unique hollow nature of the PtCo NS provided a large specific surface area, which could amplify the catalytic reaction of H2O2 to induce reactive oxygen species and cancer cell apoptosis upon combination with radiation. Both in vivo and in vitro studies showed that the hollow PtCo NS could significantly inhibit tumor growth, simultaneously relieving tumor hypoxia with good biocompatibility and biosafety. This work presents a simple but multifunctional radiosensitizer with a unique hollow structure for radiotherapy enhancement.
Improving radiation effect and reducing radiation resistance is the key issue to boost the effectiveness of radiotherapy. Herein, we have developed a novel BiOBr 0.5 I 0.5 -BP heterojunction nanosheets (BOBI-BP NSs) for synergistic radiodynamic and photothermal therapy to enhance the efficacy of low-dose radiotherapy under hypoxic conditions. On one hand, this BOBI-BP heterojunction is rich in high-Z elements (Bi, I) and able to deposit high radiation doses into cancer cells, enhancing the radiotherapy effect. On the other hand, due to the heterojunction structure, a large number of electron-hole pairs can be generated and separated under X-ray trigger, which significantly improves the catalytic activity of catalyzing the overexpressed H 2 O 2 in cancer cells into highly toxic •OH, overcoming the oxygen dependence. 1 O 2 could be generated because of the unique sub-band structures of BP NSs and the synergistic effect between BOBI and BP, thereby improving the therapeutic utility of low-dose X-ray irradiation. The synergistic utility of BOBI-BP NSs as a combination of radiodynamic therapy, photothermal therapy agent and radiosensitizer was demonstrated both in vitro and in vivo. This work provides the idea to develop rational designed heterostructures as efficient therapeutic nanoplatform for cancer treatment.
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