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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]

[Display omitted] • Fe 3 O 4 /Cu 2 O-Ag nanocomposites (NCs) were designed and synthesized successfully. • We realized integration of SERS detection and photocatalytic degradation for PAHs. • Effect of Ag contents on SERS and catalytic activity of Fe 3 O 4 /Cu 2 O-Ag was studied. • SERS detection limit of Fe 3 O 4 /Cu 2 O-Ag towards PAHs was as low as 10-9 to 10-10 M. • Photocatalytic mechanism of PAHs degradation by Fe 3 O 4 /Cu 2 O-Ag was proposed. Polycyclic aromatic hydrocarbons (PAHs) with carcinogenic, teratogenic and mutagenic properties are persistent organic pollutants in the environment. Herein, the novel multifunctional Fe 3 O 4 /Cu 2 O-Ag nanocomposites (NCs) have been established for ultra-sensitive surface-enhanced Raman scattering (SERS) detection and visible light-driven photocatalytic degradation of PAHs. Fe 3 O 4 /Cu 2 O-Ag NCs with different amounts of Ag nanocrystals were synthesized, and the effect of Ag contents on SERS performance was studied by finite-difference time-domain (FDTD) algorithm. The synergistic interplay of electromagnetic and chemical enhancement was responsible for excellent SERS sensitivity of Fe 3 O 4 /Cu 2 O-Ag NCs. The limit of detection (LOD) of optimal SERS substrates (FCA-2 NCs) for Nap, BaP, Pyr and Ant was as low as 10-9, 10-9, 10-9 and 10-10 M, respectively. The SERS detection of PAHs in actual soil environment was also studied. Moreover, a simple SERS method was used to monitor the photocatalytic process of PAHs. The recovery and reuse of Fe 3 O 4 /Cu 2 O-Ag NCs were achieved through magnetic field, and the outstanding SERS and photocatalytic performance were still maintained even after eight cycles. This magnetic multifunctional NCs provide a unique idea for the integration of ultra-sensitive SERS detection and efficient photocatalytic degradation of PAHs, and thus will have more hopeful prospects in the field of environmental protection. [ABSTRACT FROM AUTHOR]

[Display omitted] • Fe 3 O 4 /Cu 2 O-Ag nanocomposites (NCs) were designed and synthesized successfully. • We realized integration of SERS detection and photocatalytic degradation for PAHs. • Effect of Ag contents on SERS and catalytic activity of Fe 3 O 4 /Cu 2 O-Ag was studied. • SERS detection limit of Fe 3 O 4 /Cu 2 O-Ag towards PAHs was as low as 10-9 to 10-10 M. • Photocatalytic mechanism of PAHs degradation by Fe 3 O 4 /Cu 2 O-Ag was proposed. Polycyclic aromatic hydrocarbons (PAHs) with carcinogenic, teratogenic and mutagenic properties are persistent organic pollutants in the environment. Herein, the novel multifunctional Fe 3 O 4 /Cu 2 O-Ag nanocomposites (NCs) have been established for ultra-sensitive surface-enhanced Raman scattering (SERS) detection and visible light-driven photocatalytic degradation of PAHs. Fe 3 O 4 /Cu 2 O-Ag NCs with different amounts of Ag nanocrystals were synthesized, and the effect of Ag contents on SERS performance was studied by finite-difference time-domain (FDTD) algorithm. The synergistic interplay of electromagnetic and chemical enhancement was responsible for excellent SERS sensitivity of Fe 3 O 4 /Cu 2 O-Ag NCs. The limit of detection (LOD) of optimal SERS substrates (FCA-2 NCs) for Nap, BaP, Pyr and Ant was as low as 10-9, 10-9, 10-9 and 10-10 M, respectively. The SERS detection of PAHs in actual soil environment was also studied. Moreover, a simple SERS method was used to monitor the photocatalytic process of PAHs. The recovery and reuse of Fe 3 O 4 /Cu 2 O-Ag NCs were achieved through magnetic field, and the outstanding SERS and photocatalytic performance were still maintained even after eight cycles. This magnetic multifunctional NCs provide a unique idea for the integration of ultra-sensitive SERS detection and efficient photocatalytic degradation of PAHs, and thus will have more hopeful prospects in the field of environmental protection. [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]

Tetracycline (TC) is widely distributed in environment and a significant environmental pollutant. It has been challenging to rapidly identify and effectively remove TC contaminants. This work produced a multifunctional Fe 3 O 4 -Cu 2 O-Au-MIPs nanocomposite (FCAu-MIPs NCs) based on molecular imprinting technology for selective SERS detection and photocatalytic degradation of TC. We synthesized FCAu NCs with various Au contents and analyzed the relationship between Au content and SERS performance using finite-difference time-domain (FDTD) technique. Exceptional SERS performance could be attributed to the dense distribution of multiple hotspots on the SERS substrate. The photocatalytic mechanism of FCAu-MIPs NCs towards TC was also discussed. The combination of the narrow-bandgap semiconductor Cu 2 O and noble metal Au with localized surface plasmon resonance (LSPR) effect facilitated efficient light absorption and enhanced charge carrier transfer efficiency. Both SERS detection limits as low as 10−9 M and selective photocatalytic degradation of TC in soil were achieved. Furthermore, FCAu-MIPs NCs were successfully recovered and reused with assistance of external magnetic field. After six cycles, outstanding SERS and photocatalytic capacities from FCAu-MIPs NCs could still be maintained. The FCAu-MIPs NCs with selective recognition ability to TC should thus hold tremendous applicative possibilities for highly sensitive detection and efficient degradation of TC. [Display omitted] • A novel Fe 3 O 4 -Cu 2 O-Au-MIPs was successfully constructed. • The effect of gold content on SERS performance was simulated by FDTD method. • Integration of targeted degradation and specific SERS detection by FCAu-MIPs. • Electron transfer mechanism between Cu 2 O and Au nanocrystals was analyzed. • Limit of detection of FCAu-MIPs NCs for TC was as low as 10−9 M. [ABSTRACT FROM AUTHOR]

Human health is greatly threatened by bacterial infection, which raises the risk of serious illness and death in humans. For early screening and accurate treatment of bacterial infection, there is a strong desire to undertake ultrasensitive detection and effective killing of pathogenic bacteria. Herein, a novel surface-enhanced Raman scattering (SERS) biosensor based on sandwich structure consisting of capture probes/bacteria/SERS tags was established for specific identification, capture and photothermal killing of Escherichia coli (E. coli). Finite-difference time-domain (FDTD) technique was used to simulate the electromagnetic field distribution of capture probes, SERS tags and sandwich-type SERS substrate, and a possible SERS enhancement mechanism based on sandwich structure was presented and discussed. Sandwich-type SERS biosensor successfully achieved distinctive identification and magnetic beneficiation of E. coli. In addition, a single SERS substrate, including capture probes and SERS tags, could also achieve outstanding photothermal effects as a consequence of localized surface plasmon resonance (LSPR) effect. Intriguingly, sandwich-type SERS biosensor demonstrated a higher photothermal conversion efficiency (50.03 %) than the single substrate, which might be attributed to the formation of target bacterial clusters. The superior biocompatibility and the low toxicity of the sandwich-type biosensor were confirmed. Our approach offers a fresh method for constructing sandwich-type biosensor with multiple SERS hotspots based on extremely effective hybrid plasmonic nanoparticles, and has a wide range of potential applications in the recognition and treatment of bacteria. [Display omitted] • SERS platform for simultaneous detection and inactivation of E. coli was developed. • A dual SERS enhancement strategy based on sandwich-type structure was applied. • The limit of detection for E. coli was as low as 10 cfu/mL. • Photothermal conversion efficiency of the SERS platform was as high as 50.03 %. • SERS biosensor had an excellent photothermal performance for killing of E. coli. [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]