CuS nanodots-loaded biohybrid magnetic helical microrobots with enhanced photothermal performance

Magnetic helical microrobots swimming at low Reynolds numbers have attracted much interest because of their great potentials for biomedical applications. However, to endow them with sophisticated function integration toward targeted disease treatment still remains a major challenge. Here, we proposed a novel strategy of using Spirulina scaffolds to fabricate biohybrid magnetic helical microrobot (BMHM) with enhanced photothermal performance to fight against cancer cells and pathogenic bacteria. For the first time, CuS nanodots were densely and uniformly loaded intracellularly inside Spirulina cells after permeabilization, and Fe₃O₄ nanoparticles were subsequently deposited on the cell walls for magnetization. The BMHMs could be actuated forward at a high velocity and flexibly steered under rotating magnetic fields. Rapid and great photothermal temperature raise with robust cycling stability was achieved under 808 nm near-infrared laser irradiation. The BMHMs showed good biocompatibility with minor toxicity to HeLa cancer cells and Escherichia coli bacteria. Moreover, significant photothermal performance was further verified via a series of experiments for anticancer therapy and bacteria killing. Because of the remarkable features and facile cost-effective fabrication, the BMHMs demonstrated great potentials as an integrated microrobot platform for future anticancer and antibacteria applications.     

富勒烯衍生物纳米颗粒水悬液对细菌生长的抑制作用

富勒烯纳米颗粒的生物学效应受到了广泛关注。本文首次测定了二加成亚甲基富勒烯[60]二膦酸四乙酯(bis-methanophosphonate fullerene, BMPF)的纳米水悬液（nano-BMPF）和富勒醇纳米水悬液（nano-fullerol）对细菌生长的影响。结果显示,nano-BMPF和nano-fullerol在黑暗条件下可抑制革兰氏阳性菌金黄色葡萄球菌的生长,且呈现浓度梯度依赖性,半抑制浓度IC50值分别为9.1 μM和4.2 μM;nano-fullerol对金黄色葡萄球菌生长的抑制可能与活性氧无关, nano-BMPF对金黄色葡萄球菌生长的抑制则可能与超氧阴离子自由基(O2.-)有关。在黑暗条件下二者对革兰氏阴性菌大肠杆菌的生长无影响。以上结果表明,这2种富勒烯衍生物纳米颗粒作为抗生素在生物医用领域具有潜在的应用前景。     

Biochemical activities and electronic spectra of different cobalt phenanthroline complexes

A series of octahedral phenanthroline cobalt chlorides, aqua and carbonates complexes have been prepared, characterized, and their antibacterial activity was studied in detail in terms of zone inhibition and minimum inhibitory concentrations. Their antioxidant activities were studied by measuring DPPH, SOD and ABTS radical scavenging activity. It was found that cobalt phenanthroline carbonate complex possessed highest antibacterial activity, antioxidant activity, degradation effect on DNA and showed moderate cytotoxicity against Hepatocellular carcinoma (HEPG-2), Mammary gland (MCF-7) and Colorectal carcinoma (HCT-116) cells.The complexes were studied with UV spectroscopy to observe the solvents effect on the electronic spectra. Equation that relates peak position λ max to solvent parameters are solved by computerized analysis using multiple regression techniques, and the correlation and regression coefficients were evaluated. The independent solvent parameters used are H-bonding ability, refractive index and dielectric constant. The FTIR spectrum was interpreted according to the actual structure.     

Preparation of Cu–Ag core–shell particles with their anti-oxidation and antibacterial properties

Cu–Ag core–shell particles were fabricated from Cu particles and silver sulphate with the environmental-friendly TA (tartaric acid, C₄H₆O₆) as reducing and chelating agent in an aqueous system. The influences of [TA]/[Ag] and [Ag]/[Cu] molar ratios on the formation of Ag coatings on the Cu particles were investigated. The SEM images and SEM–EDS analyses showed that [TA]/[Ag] = 0.5 and [Ag]/[Cu] ≥0.2, the Cu particles were coated with uniform Ag nanoparticles. XRD analyses revealed that for these Cu–Ag particles heated at 250 °C, the oxidation of Cu was significantly reduced. Both anti-Staphylococcus aureus (Gram-positive) and anti-Escherichia coli (Gram-negative) characteristics of this Cu–Ag composite particles showed satisfactory antibacterial ability. The characteristics of the composite Cu–Ag particles were discussed in detail.