Yingpan Song

Fe(III)-based metal–organic framework-derived core–shell nanostructure: Sensitive electrochemical platform for high trace determination of heavy metal ions

A new core-shell nanostructured composite composed of Fe(III)-based metal-organic framework (Fe-MOF) and mesoporous Fe3O4@C nanocapsules (denoted as Fe-MOF@mFe3O4@mC) was synthesized and developed as a platform for determining trace heavy metal ions in aqueous solution. Herein, the mFe3O4@mC nanocapsules were prepared by calcining the hollow Fe3O4@C that was obtained using the SiO2 nanoparticles as the template, followed by composing the Fe-MOF. The Fe-MOF@mFe3O4@mC nanocomposite demonstrated excellent electrochemical activity, water stability and high specific surface area, consequently resulting in the strong biobinding with heavy-metal-ion-targeted aptamer strands. Furthermore, by combining the conformational transition interaction, which is caused by the formation of the G-quadruplex between a single-stranded aptamer and high adsorbed amounts of heavy metal ions, the developed aptasensor exhibited a good linear relationship with the logarithm of heavy metal ion (Pb2+ and As3+) concentration over the broad range from 0.01 to 10.0nM. The detection limits were estimated to be 2.27 and 6.73 pM toward detecting Pb2+ and As3+, respectively. The proposed aptasensor showed good regenerability, excellent selectivity, and acceptable reproducibility, suggesting promising applications in environment monitoring and biomedical fields.

Iron oxide@mesoporous carbon architectures derived from an Fe(II)-based metal organic framework for highly sensitive oxytetracycline determination

A series of nanocomposites comprised of iron oxide and mesoporous carbon (denoted as Fe3O4@mC) were derived from an Fe(II)-based metal–organic framework (525-MOF) by calcining at different temperatures. The advantages of chemical functionality, strong bioaffinity, and high stability of the Fe3O4@mC can be combined with the high specific surface area of 525-MOF leading to the formation of Fe3O4@mC nanocomposites as a scaffold for oxytetracycline (OTC) aptamer strands. The use of Fe3O4@mC nanocomposites reveals high OTC detection efficiency. The nanocomposite calcined at 900 °C (denoted as Fe3O4@mC900) is found to be the best candidate toward high-sensitivity and high-selectivity detection of OTC because of its excellent functionality, nanostructural properties, and high electrochemical performance. Accordingly, the Fe3O4@mC900-based electrochemical aptasensor displays high sensitivity with a low detection limit of 0.027 pg mL−1 within a broad linear range of OTC concentration from 0.005 to 1.0 ng mL−1. The aptasensor also exhibits high selectivity, reproducibility, stability, regenerability, and applicability in milk samples. All of these results indicate that the Fe3O4@mC nanocomposites that originated from 525-MOF can be applied in the fields of trace and fast antibiotic determination.

Aptasensor Based on Hierarchical Core–Shell Nanocomposites of Zirconium Hexacyanoferrate Nanoparticles and Mesoporous mFe3O4@mC: Electrochemical Quantitation of Epithelial Tumor Marker Mucin-1

A novel nanostructured hierarchical core–shell nanocomposite of zirconium hexacyanoferrate (ZrHCF) and a mesoporous nanomaterial composed of Fe3O4 and carbon nanospheres (denoted as ZrHCF@mFe3O4@mC) was prepared and used as a novel platform for an aptasensor to detect the epithelial tumor marker mucin-1 (MUC1) sensitively and selectively. The prepared ZrHCF@mFe3O4@mC nanocomposite exhibited good chemical functionality, water stability, and high specific surface area. Therefore, large amounts of aptamer molecules resulted in high sensitivity of the developed electrochemical aptasensor toward traces of MUC1. The constructed sensor also showed a good linear relationship with the logarithm of MUC1 concentration in the broad range of 0.01 ng·mL–1 to 1.0 μg·mL–1, with a low detection limit of 0.90 pg·mL–1. The fabricated ZrHCF@mFe3O4@mC-based aptasensor exhibited not only high selectivity because of the formation of aptamer–MUC1 complex but also good stability, acceptable reproducibility, and applicability. The proposed novel strategy based on a newly prepared hierarchical core–shell nanocomposite demonstrated outstanding biosensing performance and presents potential applications in biomedical fields.

Heterostructured Bi2S3@NH2-MIL-125(Ti) nanocomposite as a bifunctional photocatalyst for Cr(VI) reduction and rhodamine B degradation under visible light

A series of bismuth sulfide (Bi2S3) nanorods and amine-functionalized Ti-based metal–organic framework heterojunctions [denoted by Bi2S3@NH2-MIL-125(Ti)] were constructed and explored as bifunctional photocatalysts for Cr(VI) reduction and rhodamine B (RhB) degradation under visible light illumination. Compared with the individual NH2-MIL-125(Ti) and Bi2S3, the as-synthesized Bi2S3@NH2-MIL-125(Ti) photocatalyst exhibited an enhanced photocatalytic activity toward Cr(VI) and RhB owning to the synergetic effect between Bi2S3 and NH2-MIL-125(Ti). Moreover, the Bi2S3@NH2-MIL-125(Ti) heterojunctions showed increased Cr(VI) removal efficiency by adding RhB in the system. The photocatalytic mechanism was proposed based on the analysis of different scavenger for active species and electron spin resonance spectrometry. The introduction of Bi2S3 into NH2-MIL-125(Ti) can extend the light adsorption and improve the transfer and separation of photogenerated charge carriers through the Bi2S3@NH2-MIL-125(Ti) heterojunction with unique band gap structure. The synthesized Bi2S3@NH2-MIL-125(Ti) photocatalyst also exhibited good reusability and stability.

Bimetallic NiFe oxide structures derived from hollow NiFe Prussian blue nanobox for label-free electrochemical biosensing adenosine triphosphate

We designed and constructed a novel aptasensor based on the porous nanostructured bimetallic NiFe-oxides embedded with the mesoporous carbon (represented by NiOxFeOy@mC) for sensitively detecting adenosine triphosphate (ATP), of which the porous NiOxFeOy@mC was derived from the hollow NiFe Prussian blue analogue (hollow NiFe PBA) by calcinating under high temperature. Owning to the excellent electrochemical activity originated from the metal oxides and mesoporous carbon and the strong binding interaction between the aptamer strands and the nanostructure hybrid, the formed porous NiOxFeOy@mC composite calcinated at 900 °C exhibited superior sensitivity toward ATP determination in comparison with other porous nanocubes obtained at 500 and 700 °C. The proposed aptasensor not only revealed a wide linear range from 5.0 fg·mL-1 to 5.0 ng mL-1 with a extremely low detection limit of 0.98 fg·mL-1 (1.62 fM) (S/N = 3), but also displayed high selectivity towards other interferences, good stability and reproducibility, and acceptable applicability. Therefore, this proposed approach provides a promising platform for ultra-sensitive detection of ATP, further having the potential applications on diagnosis of ATP-related diseases.

Novel nanoarchitecture of Co-MOF-on-TPN-COF hybrid: Ultralowly sensitive bioplatform of electrochemical aptasensor toward ampicillin

Owning to the misuse of the antibiotics in animal husbandry and agriculture, it is highly urgent to determine the quantification of antibiotics in biological systems by the simple, sensitive, and fast method. In this work, a novel nanoarchitecture of Co-based metal-organic frameworks (Co-MOF) and terephthalonitrile-based covalent organic framework (TPN-COF) was synthesized (represented by Co-MOF@TPN-COF), followed by the exploitation as the bioplatform of non-label aptasensor for detecting the most frequently used β-lactam antibiotics, ampicillin (AMP). The new porous hybrid material of Co-MOF@TPN-COF was synthesized by adding the as-prepared TPN-COF into the Co-MOF preparation system. The multilayered Co-MOF@TPN-COF nanosheets exhibit a high specific surface area (52.64 m2 g-1), nitrogen-rich groups and excellent electrochemical activity. As a result, large amounts of aptamer strands can be bound over the Co-MOF@TPN-COF nanosheets owning to the strong π-π stacking and hydrogen bonds. When detecting AMP by the electrochemical impedance spectroscopy, the fabricated Co-MOF@TPN-COF-based aptasensor exhibits an ultra-low detection limit of 0.217 fg mL-1 within the AMP concentration from 1.0 fg mL-1 to 2.0 ng mL-1, which was superior to those previously reported in literatures. In addition, this proposed aptasensor also shows high selectivity, good reproducibility and stability, acceptable regenerability, and favorable applicability in human serum, river water and milk. Therefore, the proposed Co-MOF@TPN-COF-based aptasensor has a great promise to be applied as a powerful tool in the fields of food safety.

Chemical structure of hollow carbon spheres and polyaniline nanocomposite

In this data article, the chemical data of hollow carbon spheres and polyaniline (HCS@PANI) nanocomposite are presented for the research article entitled “Novel electrochemical biosensor based on core-shell nanostructured composite of hollow carbon spheres and polyaniline for sensitively detecting malathion” (He et al., 2018) [1]. The data includes chemical structure and components obtained by Raman spectra, X-ray photoelectron spectroscopy (XPS), and nitrogen adsorption and desorption isotherms.

Core-shell heterostructured CuFe@FeFe Prussian blue analogue coupling with silver nanoclusters via a one-step bio-inspired approach: Efficiently non-label aptasensor for detecting bleomycin in various aqueous environments

We synthesized novel core-shell heterostructured Prussian blue analogue (PBA) nanospheres coupled with silver nanoclusters (AgNCs) via a one-step bioinspired approach and further exploited these as aptasensors for the detection of a trace antibiotic, bleomycin (BLM). Using FeFe Prussian blue (FeFe PB) as the core, a bimetallic CuFe@FeFe PBA layer was prepared by coupling with AgNCs synthesized by taking the BLM-targeted aptamer as a template (denoted by AgNCs/Apt@CuFe@FeFe). The coupling of AgNCs/Apt via a one-step bioinspired approach not only can improve the sensing performance of CuFe@FeFe-based aptasensors but also can shorten the aptasensor fabrication procedure. Due to the strong coordination interaction between abundant Fe(II) ions contained in CuFe@FeFe PBA nanospheres and BLM (represented by Fe(II)·BLM), the Fe(II)·BLM complex formed enables aptamer strands to undergo an irreversible cleavage event that can result in a significant change in electrochemical activity. Electrochemical results displayed that both CuFe@FeFe- and AgNCs/Apt@CuFe@FeFe-based aptasensors exhibited high sensitivity and selectivity, good stability and reproducibility, and acceptable applicability toward BLM. In comparison with the pristine CuFe@FeFe-based aptasensor (limit of detection (LOD) = 0.49 fg mL-1 within the BLM concentration from 1.0 to 2.0 ng mL-1), the as-prepared AgNCs/Apt@CuFe@FeFe-based aptasensor gave a extremely lower LOD value of 0.0082 fg mL-1 within a relatively narrow BLM concentration range (0.01 fg mL-1 to 0.1 pg mL-1). The proposed method can broaden the application of PBA nanomaterials in food safety and biosensing fields and provides a potential determination method for rapidly detecting BLM in various aqueous environments.