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Here we report a novel ultrasensitive surface-enhanced Raman scattering (SERS) immunosensor based on the flower-like gold nanoparticles (AuNFs) and magnetic bead separation for homogeneous detection of amantadine (AMD) in chicken just by one-step. The 5, 5′-dithiobis (2-nitrobenzoicacid) (DTNB) modified AuNFs and N-(1-adamantyl) ethylenediamine (AEDA) conjugated denatured BSA (AEDA-dBSA) was used as the SERS nanoprobe. And the capture probe was anti-AMD monoclonal antibody (mAbs)-functionalized magnetic beads (MNBs-mAbs). An immunoreaction occurred between free AMD and SERS nanoprobe for competing limited binding sites of MNBs-mAbs. This work combined inherent sensitive property of SERS with antibody-antigen highly specificity recognition for the AMD detection. The analytical results showed that the SERS-based immunosensor was sensitive, simple and reliable with a limit of detection (LOD) of 0.005 ng/mL for AMD, which were 2 orders of magnitude better than an enzyme-linked immunosorbent assay based on the same immunoreagents. Analysis of AMD-spiked chicken samples revealed that the developed immunosensor provided accepted recoveries ranging from 74.76%-89.34% with coefficient of variation less than 15.04%. This strategy represents a simple, reliable, and universal approach for detection of chemical contaminants in food samples. [ABSTRACT FROM AUTHOR]

Camptothecin, as an antitumor drug, has shown significant antitumor activity against various cancers through the inhibition of topoisomerase I. However, its poor solubility severely limits the clinical applications. Here, we report a camptothecin supramolecular vesicle based on the host–guest interactions, which can uniformly disperse camptothecin into water and greatly enhance camptothecin aqueous solubility. The camptothecin vesicles were identified by transmission electron microscopy (TEM), scanning electron microscopy (SEM), and dynamic light scattering (DLS). X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), UV–vis spectrum, 1 H NMR and 2D NMR ROESY were further employed to study the formation mechanism of the vesicles. Furthermore, camptothecin could be controllably released when the competitive guests were added into the vesicles system. Finally, the camptothecin vesicles in aqueous solution exhibited comparable antitumor activity in vitro as natural camptothecin in DMSO to HeLa cells under the same conditions. [ABSTRACT FROM AUTHOR]

Curcumin is a safe and nontoxic natural potential antitumor drug. However, its extremely low aqueous solubility severely limits its clinical application. We designed a supramolecular curcumin vesicle based on different curcumin-cyclodextrin amphiphiles, which could greatly enhance the aqueous solubility of curcumin up to 7000-fold. The vesicles can exist for about one month in aqueous solution at around 20 °C, showing a certain colloidal stability. The curcumin-β-cyclodextrin vesicles were identified by transmission electron microscopy (TEM), scanning electron microscopy (SEM), atomic force microscopy (AFM), and dynamic light scattering (DLS). X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), UV–vis spectrum and 1 H NMR were further employed to study the formation mechanism of the vesicles. Curcumin vesicles were also prepared when different host molecules were employed as the hydrophilic heads of the supramolecular amphiphiles. Finally, curcumin could be controllably released with the disruption of the vesicles when the external stimuli, including competitive guest molecules, enzymes and copper ions were added into the vesicles system. [ABSTRACT FROM AUTHOR]

Highlights: [•] The supramolecular vesicles constructed by cyclodextrin–ftorafur supramolecular amphiphiles are reported. [•] The mechanism of the vesicles formation was studied by various methods. [•] The effect of copper ions on the vesicles was discussed. [•] The antitumor effects of the ftorafur-loaded vesicles on human colon carcinoma cell lines HT-29 were studied in detail. [Copyright &y& Elsevier]

Abstract: Vesicles constructed by supramolecular amphiphiles are considered as more promising stimuli-responsive vehicles for carrying and delivering targeted molecules. In this research, novel supramolecular amphiphiles are directly assembled from UR-144, a general neuropathic drug, and a class of mono-diaminoalkane substituted β-cyclodextrins. In the aqueous solution, the supramolecular amphiphiles can assemble into vesicular particles, which were characterized in detail by transmission electron microscopy (TEM), atomic force microscopy (AFM), scanning electron microscopy (SEM) and dynamic light scattering (DLS). The mechanism was also suggested based on the NMR, Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) experimental results. The vesicular particles tend to be damaged upon the addition of Cu2+ and meanwhile release UR-144. [Copyright &y& Elsevier]

The donor-acceptor distance is a critical factor for the occurrence of chemiluminescent resonance energy transfer (CRET). We herein evaluate the donor-acceptor distance and transfer efficiency of CRET immunoassays of a series of donors which contain different sized antibody fragments, intact monoclonal antibody (IgG), antigen binding fragment (Fab), and single chain fragment antibody (scFv). Core/multishell quantum dots were used as the acceptor in three CRET systems. IgG is the maximum antibody fragment, leading to the longest donor-acceptor distance and the lowest transfer efficiency. Donors with Fab and scFv show significantly decreased distance and increased transfer efficiency. These results suggest an inverse correlation between donor size and transfer efficiency and can be used to provide guidance for the construction of controllable CRET. By combining the controllable CRET with immunoassay, we further develop a tunable sulfamethazine analytical system. Three different sized donors based CRET immunoassay show a markedly different sensitivity and dynamic range. Such adjustable detection provides greater flexibility for contaminant detection in different foodstuffs with different residue limits. This work not only illustrates the effect of donor-acceptor distance on regulating the energy transfer efficiency of CRET system, but also provides a guideline for the construction of a tunable immunoassay. Image 1 • We developed a CRET-based immunoassay with tunable sensitivity and dynamic range. • Controllable CRET was driven by antibody engineering. • Three antibody fragments with different sizes were used as donors in CRET system. • This work provides a guideline for the construction of a tunable immunoassay. [ABSTRACT FROM AUTHOR]

Highlights: [•] A fenspiride/β-CD complex was prepared and characterized in detail. [•] An enzyme-responsive assembly system was constructed. [•] The system included reversible control of formation and disruption of vesicles. [ABSTRACT FROM AUTHOR]