In this study, a novel dual-emission ratiometric fluorescent nanoprobe (RFN) was synthesized and ultilized for highly sensitive determination of mercury ions. In this nanoprobe, fluorescein isothiocyanate (FITC) doped silica (SiO₂) served as a reference signal, FITC–SiO₂ microspheres were synthesized and modified with amino groups, and then Au Nanoclusters (AuNCs) were combined with the amino groups on the surface of the FITC–SiO₂ microspheres to obtain the RFN. The selectivity, stability, and pH of the RFN were then optimized, and the determination of mercury ions was performed under optimal conditions. The probe fluorescence intensity ratio (F₅₂₀ nm/F₆₈₀ nm) and Hg²⁺ concentration (1.0 × 10⁻¹⁰ mol/L to 1.0 × 10⁻⁸ mol/L) showed a good linear relationship, with a correlation coefficient of R² = 0.98802 and a detection limit of 1.0 × 10⁻¹⁰ mol/L, respectively. The probe was used for the determination of trace mercury ion in water samples, and the recovery rate was 98.15~100.45%, suggesting a wide range of applications in monitoring pollutants, such as heavy metal ion and in the area of environmental protection.

Aim: The development of new and efficient antibacterial agents is urgent to overcome emerging antimicrobial resistance. Materials & methods: Herein, we have presented a new-type of 3D antibacterial system to prompt bacteria to contact with the any plane of nanocomposites.Results: Comparing the antibacterial activity of graphene oxide, reduced graphene oxide and graphene-loaded nanoflower-like nickelous hydroxide (GN/Ni(OH)₂) nanocomposites; the GN/Ni(OH)₂ showed stronger bactericidal capability toward Gram-negative/-positive bacteria. Moreover, the GN/Ni(OH)₂ with low cytotoxicity can promote it as ‘green’ antimicrobial agents. And, the GN/Ni(OH)₂ presented long-term stable antibacterial effectiveness after 2-month storage. The antibacterial mechanisms of GN/Ni(OH)₂ were evidenced as the 3D contact and violent damage to the bacterial structure. Conclusion: The GN/Ni(OH)₂ provides new insights into the antibacterial properties of 3D nanocomposites for effectively fighting pathogen threats in biomedicine and public health.

In this work, we have fabricated a novel difunctional magnetic fluorescent nanohybrid (DMFN) for the determination of cadmium ions (Cd²⁺) in water samples, where the “off-on” model and “ion-imprinting” technique were incorporated simultaneously. The DMFN were composed of CdTe/CdS core-shell quantum dots (QD) covalently linked onto the surface of polystyrene magnetic microspheres (PMM) and characterized using ultraviolet-visible spectroscopy (UV-Vis), fluorescence spectroscopy, and transmission electron microscopy (TEM). Based on the favorable magnetic and fluorescent properties of the DMFN, the chemical etching of ethylene diamine tetraacetic acid (EDTA) at the surface produced specific Cd²⁺ recognition sites and quenched the red fluorescence of outer CdTe/CdS QD. Under optimal determination conditions, such as EDTA concentration, pH, and interfering ions, the working curve of determining Cd²⁺ was obtained; the equation was obtained Y = 34,759X + 254,894 (R = 0.9863) with a line range 0.05–8 μM, and the detection limit was 0.01 μM. Results showed that synthesized magnetic fluorescent microspheres had high sensitivity, selectivity, and reusability in detection. Moreover, they have significant potential value in fields such as biomedicine, analytical chemistry, ion detection, and fluorescence labeling.

Introduction: Combined multimodal therapy for breast cancer is a promising therapeutic approach to increase treatment efficacy and reduce systemic toxicity. The present study aimed to develop a novel multifunctional drug release nanoplatform based on RGD-conjugated hyaluronic acid (HA)-functionalized copper sulfide (CuS) for activatable dual-targeted synergetic therapy against cancer. Methods: The pH and NIR-responsive dual-targeting nanoplatform CuS:Ce6@HA:DOX@RGD was prepared, characterized, and evaluated for its stability and photodynamic and photothermal properties. The loading and release of the drug were measured at different pH values with or without laser radiation using the dialysis method. The cellular uptake of the platform specifically by the tumor cells treated with different formulations was investigated through fluorescence imaging. The in vitro and in vivo biosafety levels were assessed systematically. Finally, the antitumor efficiencies against breast cancer were assessed via in vitro and in vivo experiments. Results: The spheroid CuS:Ce6@HA:DOX@RGD exhibited remarkable stability and monodispersity in solution. The photosensitive CuS and Ce6 could simultaneously absorb the near-infrared light efficiently to convert NIR light to fatal heat and to generate reactive oxygen species. The CuS:Ce6@HA:DOX@RGD dissociated under an acid environment, causing the release of DOX into the tumor to accelerate upon laser irradiation. The CuS:Ce6@HA:DOX@RGD exhibited target-specific and strong binding ability via a synergic CD44/αvβ₃ receptor-mediated bimodal targeting, which led to improved therapeutic efficacy. The tumor growth was effectively inhibited using synergetic photodynamic/photothermal/chemo therapy. No evident systemic toxicity was noted during treatment. Conclusion: The newly prepared CuS:Ce6@HA:DOX@RGD has great potential as an activatable theranostic nanoplatform for efficient dual-targeted synergistic therapy against breast cancer.

A surface-enhanced Raman scattering (SERS) tag is proposed for high-sensitivity detection of gibberellin A₃ (GA₃). Silver nanoparticles (AgNPs) were synthesized using citrate reduction. 4-Mercaptobenzoic acid (MBA) was used for the Raman-labeled molecules, which were coupled to the surface of the AgNPs using sulfydryls. MBA was coated with silica using the Stöber method to prevent leakage. GA₃ antibodies were attached via the active functional groups N-Hydroxysuccinimide (NHS) and N-Ethyl-N’-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC) to construct a novel immuno-AgNPs@SiO₂ SERS tags. The captured SERS substrates were fabricated through Fe₃O₄ nanoparticles and gold nanoparticles (AuNPs) using chemical methods. These nanoparticles were characterized using ultraviolet-visible spectroscopy (UV–Vis), dynamic light scattering, Raman spectroscopy, transmission electron microscope (TEM), and X-ray diffraction (XRD). This immuno-AgNPs@SiO₂ SERS tags has a strong SERS signal based on characterizations via Raman spectroscopy. Based on antigen-antibody reaction, the immuno-Au@Fe₃O₄ nanoparticles can capture the GA₃ and AgNPs@SiO₂ SERS tags. Due to the increasing number of captured nanoprobes, the SERS signal from MBA was greatly enhanced, which favored the sensitive detection of GA₃. The linear equation for the SERS signal was y = −13635x + 202211 (R² = 0.9867), and the limit of detection (LOD) was 10⁻¹⁰ M. The proposed SERS tags are also applicable for the detection of other food risk factors.