Taofeng Zhu

Anticancer Activity and DNA‐Binding Investigations of the Cu(II) and Ni(II) Complexes with Coumarin Derivative

Two new copper(II) (2) and nickel(II) (3) complexes with a new coumarin derivative have been synthesized and structurally characterized. The DNA‐binding activities of the two complexes have been investigated by spectrometric titrations, ethidium bromide displacement experiments, CD (circular dichroism) spectral analysis, and viscosity measurements. The results indicate that the two complexes, especially the complex 2, can strongly bind to calf‐thymus DNA (CT‐–DNA). The intrinsic binding constants Kb of the complexes with CT‐DNA are 2.99 × 105 and 0.61 × 105 for 2 and 3, respectively. Comparative cytotoxic activities of the two complexes are also determined by MTT assay. The results show that the drugs designed here have significant cytotoxic activity against the human hepatic (HepG2), human promyelocytic leukemia (HL60), and human prostate (PC3) cell lines. Cell apoptosis was detected by Annexin V/PI flow cytometry, and the results show that the two copper complexes can induce apoptosis of the three human tumor cells. In conclusions, the two complexes show considerable cytotoxic activity against the three human cancer and induce apoptosis of the threes.

Visible light-induced lanthanide polymer nanocomposites based on clays for bioimaging applications

Lanthanide complexes have attracted increased attention in recent years for their unique photophysical properties such as large Stokes shifts, narrow bandwidth, long radiative lifetimes, and high luminescence quantum yield. However, low photochemical stability and poor mechanical properties limit the technological applicability of lanthanide complexes. Two natural clay minerals, fibrillar palygorskite (Pal) and tubular halloysite nanotubes (HNTs), are known for their extreme stabilities and high surface area and show promise as new carriers of luminescent lanthanide complexes for further applications. In this report, clay-based lanthanide polymer nanocomposites clay–polyethyleneimine (PEI)–MPTP–Eu(DBM)3 have been fabricated by attaching a lanthanide complex onto the surface of PEI-modified Pal or HNTs. The formed nanocomposites display visible light-excitable features with a wide excitation wavelength range from UV to visible light, a long luminescence lifetime, and improved photoluminescence stability. Their excellent luminescence, high suspension stability, and low cytotoxicity in cell studies result in the potential applications of the as-prepared nanocomposites for cell imaging in biological systems.

Multifunctional nanocomposite based on halloysite nanotubes for efficient luminescent bioimaging and magnetic resonance imaging

A novel multifunctional halloysite nanotube (HNT)-based Fe3O4@HNT-polyethyleneimine-Tip-Eu(dibenzoylmethane)3 nanocomposite (Fe-HNT-Eu NC) with both photoluminescent and magnetic properties was fabricated by a simple one-step hydrothermal process combined with the coupling grafting method, which exhibited high suspension stability and excellent photophysical behavior. The as-prepared multifunctional Fe-HNT-Eu NC was characterized using various techniques. The results of cell viability assay, cell morphological observation, and in vivo toxicity assay indicated that the NC exhibited excellent biocompatibility over the studied concentration range, suggesting that the obtained Fe-HNT-Eu NC was a suitable material for bioimaging and biological applications in human hepatic adenocarcinoma cells. Furthermore, the biocompatible Fe-HNT-Eu NC displayed superparamagnetic behavior with high saturation magnetization and also functioned as a magnetic resonance imaging (MRI) contrast agent in vitro and in vivo. The results of the MRI tests indicated that the Fe-HNT-Eu NC can significantly decrease the T2 signal intensity values of the normal liver tissue and thus make the boundary between the normal liver and transplanted cancer more distinct, thus effectively improving the diagnosis effect of cancers.

Ternary Dinuclear Copper(II) Complexes of a Reduced Schiff Base Ligand with Diimine Coligands: DNA Binding, Cytotoxic Cell Apoptosis, and Apoptotic Mechanism.

A serial of mixed‐ligand Cu(II) complexes of the type [Cu(phens)(H2PDILeu)]H2O (1‐4) containing phens as 2,2′‐bipyridyl (bpy, 1), 1,10‐phenanthroline (phen, 2), dipyrido[3,2‐d:2′,3′‐f]quinoxaline (dpq, 3), and dipyrido[3,2‐a:2′,3′‐c]phenazine (dppz, 4) have been isolated and characterized. The interaction of the complexes with calf‐thymus DNA has been explored by physical methods to propose modes of DNA binding of the complexes, which indicate that 4 interacts with DNA more strongly than all of the other complexes through intercalation interaction. Furthermore, cell apoptosis was detected by AnnexinV/PI flow cytometry and TUNEL assay and by Western blotting to detect the protein expression of p53, Bax, and Bcl‐2. All the three copper complexes can effectively induce apoptosis of the three human tumor cells, which was accompanied with upregulation of the expression of p53 and Bax, while Bcl‐2 decreased.

DNA damage in peripheral blood lymphocytes from patients with OSAHS

PurposeObstructive sleep apnea hypopnea syndrome (OSAHS) is characterized by intermittent hypoxia during sleep time, followed by oxidative stress. Hypoxia-induced oxidative stress can lead to DNA damage, which is related to chromosome aberrations and micronuclei. The purpose of this study is to investigate the level of DNA damage in peripheral blood of patients with OSAHS.MethodsThirty patients with OSAHS diagnosed by polysomnography and 28 healthy volunteers were assessed by the Epworth sleepiness scale. The levels of DNA damage were investigated through the cytokinesis-blocked micronucleus assay.ResultsIn the group of patients with OSAHS, the mean frequency of binucleated cells with micronuclei were significantly higher than that in the control group (P < 0.01), and the frequency of micronuclei among the patients in mild, moderate, and severe stages differed significantly (P < 0.05). The mean frequency of nucleoplasmic bridge in OSAHS group was also higher than that in the control group (P < 0.05). Nasal continuous positive airway pressure treatment decreased the frequencies of binucleated cells with micronuclei, nucleoplasmic bridge, and nuclear buds.ConclusionsOxidative DNA damage increased in peripheral blood lymphocytes of OSAHS patients. It may be related to oxidative stress induced by intermittent hypoxia and may be involved in the pathogenesis of cardiovascular and other target organ injuries.

A novel visual ratiometric fluorescent sensing platform for highly-sensitive visual detection of tetracyclines by a lanthanide- functionalized palygorskite nanomaterial

A palygorskite (Pal)-based ratiometric fluorescent nanoprobe is designed in order to establish a real time, on-site visual, and highly sensitive detection method for tetracyclines (TCs). The nanoprobe comprises the green emissive dye molecules embedded in the natural Pal, which serve as the internal reference signal. The potential red-emissive seed-europium (Eu3+) ions are covalently bound on the surface of modified Pal, and they can act as the specific recognition element. The emission intensity of Eu3+ ions significantly increases upon TC addition. The nanoprobe fluorescence changes from green to yellow, orange, or red, thereby accomplishing the visual ratiometric fluorescent detection. This nanoprobe exhibits a high sensitivity with a detection limit of 7.1nM and an excellent selectivity in monitoring the levels of TCs in milk samples. In addition, this nanoprobe is useful for quantitative determination of TCs, and it is not affected with intensity fluctuations due to instrumental or environmental factors. The nanoprobe-immobilized test paper realizes real-time TCs analysis by using a smartphone with an easy-to-access color-scanning APP as the detection platform. Moreover, the reported construction of visual ratiometric detection system follows the sustainable development idea, that is, from nature, for nature, and into the nature.