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[Display omitted] • A novel BiOBr/ZnFe 2 O 4 -GO S-scheme heterojunction was successfully constructed. • The effect of GO content on catalytic activity of BOB/ZFO-GO NCs was investigated. • BOB/ZFO-GO NCs achieved photothermal synergistic catalysis for TC. • The mechanism of BOB/ZFO-GO NCs catalytic degradation for TC was analyzed. • Photothermal detection sensor has a detection limit as low as 10-4 ng/mL for TC. The threat of tetracycline (TC) to human health has become a significant issue that cannot be disregarded. Herein, in order to achieve effective degradation and high-sensitivity detection of TC, BiOBr/ZnFe 2 O 4 -GO (BOB/ZFO-GO) S-scheme heterojunction nanocomposites (NCs) have been prepared using hydrothermal method. GO with high light absorption capacity accelerated the electron transfer between BiOBr and ZnFe 2 O 4 nanocrystals and extended the light absorption region of BOB/ZFO NCs. The optimal GO addition of BOB/ZFO-GO NCs could degrade TC solution of 10 mg/L in 80 min and have a high reaction rate constant (k) of 0.072 min−1 under visible/NIR light. According to calculations, the non-metal photocatalyst (BOB/ZFO-GO(2)) with the best degradation performance had a photothermal conversion efficiency of up to 23%. Meanwhile, BOB/ZFO-GO NCs could be recycled by magnetic field. The excellent photocatalytic and photothermal performance could be maintained even after several cycles. In addition, a photothermal detection sensor based on a photothermal material/specific recognition element/tetracycline sandwich-type structure was constructed for the trace detection of TC concentration with a detection limit as low as 10-4 ng/mL. This research provides a unique idea for the multi-functionalization of photocatalysts and has a wide range of potential applications for the identification and treatment of organic wastewater. [ABSTRACT FROM AUTHOR]

The development and application in different fields of multifunctional plasmonic nanoparticles (NPs) have always been research hotspots. Herein, multi-tip Au nanostars (NSs) with an anisotropic structure were fabricated for the photothermal therapy (PTT) of bacteria and surface-enhanced Raman scattering (SERS) detection of pollutants. The size and localized surface plasmon resonance (LSPR) characteristics of Au NSs were adjusted by varying Au seed additions. In addition, photothermal conversion performance of Au NSs with various Au seed additions was evaluated. Photothermal conversion efficiency of Au NSs with optimal Au seed additions (50 μL) was as high as 28.75% under 808 nm laser irradiation, and the heat generated was sufficient to kill Staphylococcus aureus (S. aureus). Importantly, Au NSs also exhibited excellent SERS activity for the 4-mercaptobenzoic acid (4-MBA) probe molecule, and the local electromagnetic field distribution of Au NSs was explored through finite-difference time-domain (FDTD) simulation. As verified by experiments, Au NSs' SERS substrate could achieve a highly sensitive detection of a low concentration of potentially toxic pollutants such as methylene blue (MB) and bilirubin (BR). This work demonstrates a promising multifunctional nanoplatform with great potential for efficient photothermal inactivation and ultra-sensitive SERS detection. [ABSTRACT FROM AUTHOR]

Although simultaneous photothermal therapy (PTT) and photodynamic therapy (PDT) have been proven to be beneficial for cancer treatment, high-power laser light sources, shallow penetration depth of light and especially activation by two different light sources make it difficult to be popularized in clinical cancer therapy. Herein, the novel multifunctional Fe 3 O 4 @Au nanocomposites (NCs) have been designed and synthesized, which simultaneously act as photothermal conversion agents (PCAs) and photosensitizers (PSs) for PTT/PDT synergistic therapy of human cervical cancer (HeLa) cells using a single excitation light source. Under low-power 808 nm laser irradiation, photothermal conversion efficiency (PCE) of Fe 3 O 4 @Au NCs was as high as 39.22% and the cytotoxic singlet oxygen (1O 2) could be simultaneously generated. In addition, Fe 3 O 4 @Au NCs showed relatively good biocompatibility and low cytotoxicity, which were ideal alternatives for nanotherapeutic agents for treatment of HeLa cells. Meanwhile, PTT only and PTT/PDT dual-modal therapeutic effects of Fe 3 O 4 @Au NCs on HeLa cells were compared. The experimental results confirmed that the near-infrared (NIR)-triggered PDT/PTT synergistic therapy of HeLa cells was more efficient due to the synergistic effect. Interestingly, Fe 3 O 4 @Au NCs with saturation magnetization (Ms) value of 66.5 emu/g possessed good magnetic responsivity, which could be collected easily with a magnet. The magnetic targeting of Fe 3 O 4 @Au NCs could effectively promote their accumulation at tumor sites, thus further enhancing the efficacy of PTT/PDT synergistic therapy of HeLa cells. This study provides a feasible paradigm for magnetic targeting-assisted PTT/PDT synergistic therapy of cancer cells under a single-wavelength excitation and opens up a novel direction for clinical cancer therapy. [Display omitted] • Fe 3 O 4 @Au nanocomposites (NCs) were designed and synthesized successfully. • Fe 3 O 4 @Au NCs had good photothermal effect and ability to generate singlet oxygen. • Fe 3 O 4 @Au NCs achieved simultaneous triggering of PTT and PDT under single laser. • Effect of PTT/PDT dual-modality therapy on cell viability of HeLa cell was studied. • Effect of magnetic targeting on PTT/PDT treatment of HeLa cell was investigated. [ABSTRACT FROM AUTHOR]