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The rapid nucleic acid extraction is essential, particularly the communicable diseases pandemic. In this work, aluminum modified Fe3O4 (Fe3O4@Al3+) particles were successfully synthesized by solvthermal method, epoxidation, covalent binding of iminodiacetic acid and Al3+ ions coordination for DNA extraction. Fe3O4@Al3+ particles could greatly improve the efficiency of DNA extraction and the extraction could be totally completed within 15 minutes at the optimum condition. The simple and rapid method is mainly based on the Fe3O4@Al3+ particles, which have large specific surface area, superparamagnetism, and Al3+ ions affinity to DNA. Additionally, several characterizations were carried out to further investigate the features of Fe3O4@Al3+ particles. According to SEM image, the average dimension of monodispersed Fe3O4@Al3+ spheres was around 200 nm. XPS results showed the existence of Al3+ on the surface of Fe3O4 particles, which further demonstrated the success of metal chelation in this material synthesis. The XRD patterns indicated that the Fe3O4@Al3+ particles were the inverse spinel structure as the bare Fe3O4 particles. Good magnetism of Fe3O4@Al3+ particles determined by VSM indicated that this material could be easily separated from the reaction system. To summarize, Fe3O4@Al3+ particles is expected to play an important role in future DNA extraction due to remarkable performance. The DNA separation media Fe3O4@Al3+ particles were successfully synthesized. DNA adsorption was effectively achieved by Fe3O4@Al3+ particles based on metal chelation. DNA extraction was significantly boosted by Fe3O4@Al3+ particles. [ABSTRACT FROM AUTHOR]

An electrochemiluminescence (ECL) aptasensor was prepared to detect Pb2+ with nitrogen-doped carbon quantum dots (NCQDs) as ECL materials. To prepare the working electrode, NCQDs with carboxyl groups were loaded on a glassy carbon electrode (GCE) and then Pb2+ aptamers were covalently bound to the NCQDs to form a stable GCE/NCQDs/aptamers. On addition of Pb2+, the chain aptamers change to a pb2+ G-quadruplex conformation, which lead to a large decrease in the ECL intensity. The variation of intensity and the logarithm of the Pb2+ concentration had a good linear relationship (R2 = 0.998). The detection range was wide (50 pM to 387.9 nM) with a low detection limit (18.9 pM). In interference experiments, the ECL Pb2+ aptasensor did not suffer from interference and it had good stability. The NCQDs ECL aptasensor can detect Pb2+ quickly and accurately, and provides a fast and efficient method for detection of Pb2+. Compared with literatures, the Pb2+ aptasensor has simpler preparation process, lower cost; furthermore, it is more environmentally friendly. [ABSTRACT FROM AUTHOR]

Superparamagnetic Fe3O4hollow sub-microspheres (FHSM) with strong response to an external magnet were prepared via a solvothermal method, followed by acid etching. Lipase fromCandidasp. 99–125 was directly immobilized onto the amino-functional FHSM by simple adsorption, without glutaraldehyde linkage. The immobilized lipase was used to catalyze the esterification/transesterification of waste cooking oil with methanol to produce fatty acid methyl ester (FAME), a major source of biodiesel. FAME yield exceeded 93.4% over a wide range of temperatures from 10 to 40 °C. Notably, stability was clearly improved at the lower temperatures, in particular, giving a FAME yield of 89.6% after eight cycles of use at 10 °C. [ABSTRACT FROM PUBLISHER]