Xuewen Ma

Ractopamine (RAC) is universally known for improving lean meat percentage in livestock and thus is widely introduced as a feed additive. However, it is difficult to eliminate the RAC residue in animal tissues from the biological system and will inevitably harm human health. Hence, detecting RAC molecules in biological samples is extremely significant. Herein, a novel strategy of supramolecular recognition-enhanced electrochemical sensing is presented. This platform was constructed by coupling β-cyclodextrin (β-CD) with palladium nanoparticles (Pd NPs)-functionalized three-dimensional reduced graphene oxide (3D-rGO) to form a nanocomposite (3D-rGO/Pd/β-CD), which was further used to modify a glassy carbon electrode (GCE) for RAC detection. Benefiting from the attractive electrical conductivity and catalytic activity of 3D-rGO/Pd, as well as the unique small-molecule-recognition ability of β-CD demonstrated by ¹H NMR spectrum, which revealed the 1 : 2 binding mode of RAC with β-CD, increased peak current signals of RAC were observed in the cyclic voltammetry (CV) test. Under optimized conditions, the wide linear concentration range spanned 1–95 μM, along with a relatively low detection limit of 0.12 μM (S/N = 3), as evidenced by the differential pulse voltammetry (DPV) approach. The platform also exhibited satisfactory stability and fine reproducibility, as well as high selectivity and good anti-interference capability. Moreover, this as-obtained sensor was efficiently applied in pork samples with a high recovery rate (96.44–103.99%), which provides a promising view of its electrochemical biosensing ability in practical applications.

A multifunctional targeted drug delivery platform (CDHA–MGO) has been successfully constructed by grafting β-cyclodextrin–hyaluronic acid polymers (CDHA) to Fe₃O₄–graphene oxide (MGO). The obtained CDHA–MGO nanocomposite has good water-dispersibility, easy magnetic separation, high near-infrared (NIR) photothermal heating, and excellent biocompatibility. The β-cyclodextrin-hyaluronic acid polymers efficaciously enhance the doxorubicin (DOX) loading amount up to 485.43 mg·g⁻¹. Meanwhile, the Fe₃O₄–graphene oxide provides a facile photothermal response mechanism to handle the NIR-triggered release of DOX in weak acidic solvent environments. Significantly, the DOX-loaded nanocomposite (DOX@CDHA–MGO) has displayed CD44 receptor-mediated active targeting recognition and chemo-photothermal synergistic therapy of hepatoma cells. These findings suggest that the as-prepared drug delivery platform would be of valuable potential for cancer-targeted photo-chemotherapy.

Surface β-cyclodextrin polymer coated Fe₃O₄ magnetic nanoparticles (NPs) were prepared by anchoring pyromellitic dianhydride derivate-b-cyclodextrin polymer (b-CD-P) onto the surface of Fe₃O₄ magnetic NPs, which is generated in situ through a co-precipitation method. The transmission electron microscopy (TEM) result indicates that Fe₃O₄@β-CD-P NPs have an effective average size of 15 ± 2 nm. The surface coated layer β-CD-P was confirmed by Fourier-Transformed Infrared Spectroscopy, and the amount of which was determined to be 138.2 mg g^-1 by thermogravimetric analysis. To explore the potential application of such nanocomposites for organic pollutants adsorption, malachite green (MG), a typical cancer-causing water pollutant was evaluated by spectrophotometric method. It was finally learnt that, the adsorption rate of MG by Fe₃O₄@β-CD-P NPs follows pseudo-second-order kinetics with adsorption isotherm fitted by the Langmuir isotherm model well. The maximum adsorption capacity was measured to be 88.49 mg g^-1 at 25 °C. Additionally, a good recyclability of the Fe₃O₄@β-CD-P was observed over four usage cycles, with slight decrease of adsorption capability.