Interfacial Supra-Assembly of Copolymer Nanoparticles Enables the Formation of Nanocomposite Crystals with a Tunable Internal Structure.

It is highly desirable but technically challenging to precisely control the spatial composition and internal structure of crystalline nanocomposite materials, especially in a one-pot synthetic route. Herein, we demonstrate a versatile pathway to tune the spatial distribution of guest species within a host inorganic crystal via an incorporation strategy. Specifically, well-defined block copolymer nanoparticles, poly(methacrylic acid)x-block-poly(styrene-alt-N-phenylmaleimide)y [PMAAx-P(St-alt-NMI)y], are synthesized by polymerization-induced self-assembly. Such anionic nanoparticles can supra-assemble onto the surface of larger cationic nanoparticles via an electrostatic interaction, forming colloidal nanocomposite particles (CNPs). Remarkably, such CNPs can be incorporated into calcite single crystals in a spatially controlled manner: the depth of CNPs incorporation into calcite is tunable. Systematic investigation indicates that this interesting phenomenon is governed by the colloidal stability of CNPs, which in turn is dictated by the PMAAx-P(St-alt-NMI)y adsorption density and calcium ion concentration. This study opens up a general and efficient route for the preparation of a wide range of crystalline nanocomposite materials with a controlled internal composition and structure.

A Sensitive Electrochemiluminescence Urea Sensor for Dynamic Monitoring of Urea Transport in Living Cells.

A multiple signal-amplified electrochemiluminescence (ECL) urea sensor was designed based on a self-enhanced probe and SiO2 photonic crystals for dynamic tracking of urea transmembrane transport. The self-enhanced probe (AuNR@Ru-LA) prepared by loading polyethyleneimine (PEI), lactobionic acid (LA), and Ru(dcbpy)32+ on gold nanorods (AuNRs) generated an initial ECL signal, and then the intensity was multiple-amplified by the enhanced light-scattering effect of SiO2 photonic crystals and the co-reaction with urea. The as-prepared sensor exhibited excellent performance for the detection of urea in the range of 1.0 × 10-10 to 1.0 × 10-4 M with a detection limit of 8.8 × 10-11 M at (3σ)/S. The AuNR@Ru-LA probes were labeled on HepG2 cells to construct a cytosensor with a detection range of 1.0 × 103 to 2.0 × 106 cells mL-1. In addition, the dynamic changes of the extracellular urea concentration were tracked by monitoring the ECL signal of the cytosensor to study urea transmembrane transport. The developed strategy realized the amplification of multiple ECL signals and the tracking of urea transmembrane transport, which provided a novel dynamic detection method for small biomolecules.

Multi-Analyte Discriminated ECL via Photonic Crystal-Enhanced Selectivity.

Electrochemiluminescence (ECL) has numerous merits such as high sensitivity and specificity for the detection applications on pharmacy, food safety, immunoassay, disease diagnosis, environmental monitoring, nucleic acid assay, and clinical treatment. However, the insufficiency of ECL luminescent reagents is restricting their adoption on complex systems or multi-analyte detections. In this work, to improve the selectivity and discrimination of ECL detection with one or less luminescent reagent, we employed multi-stopband photonic crystals (PCs) to enhance assigned ECL. The discrimination of ECL was well investigated to establish the quantitative description with PC stopbands. The multi-stopband PC electrode can facilely achieve 10 antibiotics qualitative and quantitative analysis with 100% accuracy and 0.44 µM LOD in PBS buffer and human serum. The selectivity of ECL detection for multi-analytes can be improved via designed PC luminescence amplifications. The exploration on PC selectivity for ECL enhancement will promote the realistic application of the ECL technique and contribute to the facile and efficient optical platform for clinical or health monitoring.

Morphology Dictated Immune Activation with Framework Nucleic Acids.

Framework nucleic acids (FNAs) of various morphologies, designed using the precise and programmable Watson-Crick base pairing, serve as carriers for biomolecule delivery in biology and biomedicine. However, the impact of their shape, size, concentration, and the spatial presentation of cytosine-phosphate-guanine oligodeoxynucleotides (CpG ODNs) on immune activation remains incompletely understood. In this study, representative FNAs with varying morphologies are synthesized to explore their immunological responses. Low concentrations (50 nM) of all FNAs elicited no immunostimulation, while high concentrations of elongated DNA nanostrings and tetrahedrons triggered strong activation due to their larger size and increased cellular uptake, indicating that the innate immune responses of FNAs depend on both dose and morphology. Notably, CpG ODNs' immune response can be programmed by FNAs through regulating the spatial distance, with optimal spacing of 7-8 nm eliciting the highest immunostimulation. These findings demonstrate FNAs' potential as a designable tool to study nucleic acid morphology's impact on biological responses and provide a strategy for future CpG-mediated immune activation carrier design.

QCM sensor provides insight into the role of pivotal ions in cellular regulatory volume decrease.

All vertebrate cells generally self-regulate for sustaining homeostasis and cell functions. As a major regulatory mechanism, regulatory volume decrease (RVD) occurs in hypotonicity-induced cell swelling, and then shrinking by the efflux of intracellular osmolytes and water, in which the ions K+, Cl-, and Ca2+ play a key role in the RVD process. We observed that these pivotal ions could result in novel RVD behaviors under repeatedly hypotonic stimulation. However, there is a lack of valid means for assessing the effect of pivotal ions on RVD. In this work, we proposed an effective measurement process based on a quartz crystal microbalance (QCM) combined with cell function of RVD for revealing acute variations in cell volume regulation induced by the pivotal ions. A QCM sensor was implemented by adhering MCF-7 cells to a poly-l-lysine-modified gold chip and cyclic stimulation with hypotonic NaCl medium, in which a frequency shift (Δf) showed the superior feasibility of the technique in exhibiting RVD behaviors. With the increase in the number of cycles, the RVD values decreased progressively under three stimulation cycles with hypotonic NaCl alone. Compared with the first cycle, the RVD level in the second and third cycles declined by 60.7±1.7% and 82.1±1.6% (n=3), respectively; conversely, it recovered in NaCl-KCl solution, but was significantly enhanced by 52.2±0.8% in NaCl-CaCl2 solution. Moreover, the inhibition of chloride channels to block Cl- efflux also decreased the RVD level by 56.2±3.0%. The results indicate that these ions (K+, Cl-, Ca2+) are all able to affect the function of RVD, among which intracellular Cl- depletion reduced RVD during measurement, but which recovered with K+ supplement, and Ca2+ enhanced RVD due to activation of ion channels. Therefore, this work provides a comprehensive assessment of cellular behavior and offers an innovative method for gaining insight into cellular functions and mechanisms. A novel strategy was conducted by integrating a quartz crystal microbalance (QCM) with the function of cell volume regulation for analyzing the role of the pivotal ions ( K+, Cl-, Ca2+) in NaCl media on the behaviors of regulatory cell volume decrease (RVD).

Ratiometric ECL sensor based on Apt-AuNS@Lu nanoprobe for analyzing cell swelling-induced ATP release.

A novel ratiometric electrochemiluminescence (ECL) system based on gold nanostars (AuNSs) support was constructed for the determination of hypotonicity-induced ATP release from HepG2 cells. AuNS@Lu nanoprobe was used as anodic luminophore and K2S2O8 as cathodic luminophore as well as anodic co-reactant. AuNS with the large specific surface was adopted to adsorb plentiful luminol to form solid-state probe and as affinity support to immobilize ATP aptamer (Apt). The obtained nanocomposite (Apt-AuNS@Lu) generated a strong ECL signal at + 0.4 V (vs. Ag/AgCl) with co-reactant K2S2O8, because of excellent conductivity and catalytic activity of AuNS. Furthermore, graphene oxide was reduced onto indium tin oxide (ITO) electrodes to facilitate the electron transfer. Following, polydopamine (PDA) film was formed via self-polymerization, improving stability and adhesion of the electrode surface. To immobilize ATP capture aptamer (AptC), abounding AuNSs were attached to RGO/PDA surface. When the sensor was incubated in the mixture solution of Apt-AuNS@Lu and target ATP, the ECL signal of Apt-AuNS@Lu increased with the increase of ATP concentration, meanwhile, the signal of K2S2O8 declined. The ratio of the two luminophores was used for the quantitative determination of ATP. The linear range was 5 to 250 nM, and the limit of detection was 1.4 nM at (3σ)/S. The method was successfully applied to analyze ATP release from HepG2 cells stimulated by 0.45% NaCl hypotonic solution. The results showed that the release kinetics profile of ATP had a sigmoidal shape with rapid release within 10 min and then slowed. Compared to the isotonic groups, the intracellular ATP concentration was 3.7 ± 0.3 µM (n = 3) decreasing by 40.3% and the extracellular was 23.4 ± 1.2 nM (n = 3) increasing by 9.2 times in the hypotonicity for 10 min, which showed ATP release from cells and good agreement with commercial ELISA test. The proposed strategy would be beneficial to broadening application of ECL technology in studying cell biological functions.

Real-Time Monitoring of the Regulatory Volume Decrease of Cancer Cells: A Model for the Evaluation of Cell Migration.

Cell migration plays a vital role in carcinoma invasion and metastasis. Cell regulatory volume decrease (RVD), a mechanism of adjusting cell volume, is a basic physiological function of cells, which is closely related to cell migration. In this work, a quartz crystal microbalance (QCM) cytosensor was first developed for real-time monitoring of cell RVD to evaluate the migration of human breast cancer cells. While stimulating the immobilized cells on the chip with hypotonic solutions, the temporal dynamics of RVD can be tracked by QCM sensor via analyzing frequency shifts during the cell swelling and shrinkage. The results showed that, due to the difference in cell migration capability, the level of RVD for MCF-7 cells and MDA-MB-231 cells was 32.8 ± 2.9% and 49.7 ± 4.2% ( n = 3), respectively. Furthermore, tamoxifen, a chloride channel blocker, was used to suppress cell RVD, indicating concentration dependence and inhibition difference in both types of cells. Combining QCM measurement with cell migration assay, the results showed that the blockage of RVD was positively correlated to the inhibition of cell migration with tamoxifen concentration ranging from 5 to 60 µM, which revealed the relation between cell RVD and cell migration. The study provided a noninvasive and real-time strategy for monitoring cell RVD as well as assessing cell migration, which was expected to supply a new diagnostic tool for metastatic cancers.

Full-color emissive carbon-dots targeting cell walls of onion for in situ imaging of heavy metal pollution.

Plant cell walls (CWs) with complex macromolecular structures can surround and protect cells from a variety of harsh environmental conditions such as pathogens, herbivores, and trace metals. Here, a novel strategy for in situ imaging of plant cell walls was developed to evaluate heavy metal pollution via thiolated full-color emissive carbon-dots (F-CDs) targeting Pb(ii)-adsorbed onion cell walls. The thiolated F-CDs with excellent optical properties from red light to blue light were synthesized through a facile electrochemical approach using new precursors of luminol and l-tryptophan and further modified with l-cysteine. Based on a strong covalent interaction of Pb(ii) and thiolated F-CDs, we achieved in situ fluorescence imaging for the Pb(ii) adsorbed on CWs, which showed enhanced red, blue and green multi-color fluorescence (FL) on CWs with increased Pb(ii)-ion content. In contrast, multi-color fluorescence on cytoplasm diminished, attributed to F-CDs targeting and accumulating on the cytoskeleton which thus limited F-CD diffusion into protoplasm. Therefore, in situ fluorescent images for CWs can demonstrate heavy metal contamination degrees in plant cells. This facile and undamaging protocol will be beneficial for investigating heavy metal migration into the protoplast and fast evaluation of food quality and safety.

A quartz crystal microbalance modified with antibody-coated silver nanoparticles acting as mass signal amplifiers for real-time monitoring of three latent tuberculosis infection biomarkers.

A strategy is described for continuous monitoring of multiple latent tuberculosis infection (LTBI) biomarkers, specifically of interferon-gamma (IFN-γ), tumor necrosis factor-alpha (TNF-α) and interleukin-2 (IL-2). Silver nanoparticles acting as mass signal amplifiers were linked to respective antibodies to form mass nanoprobes for increasing the mass loaded on the surface of the quartz crystal microbalance (QCM). This results in enhanced sensitivity. The mass nanoprobes can be oxidatively dissolved by hydrogen peroxide that avoided the steric hindrance caused by the scale effect of mass nanoprobes. This offers the option of signal recovery monitoring. By using this method, IFN-γ, TNF-α and IL-2 can be monitored serially. The frequency shifts caused by TNF-α, IFN-γ and IL-2, respectively, are reversible. Hence, the biomarkers can be continuously quantified. Compared to multichannel QCM sensing, the new method avoids acoustic interference and has a simplified instrumental setup. The assay is simple, accurate, sensitive, and inexpensive. Graphical abstract Silver nanoparticles as the mass signal amplifiers were linked with the antibodies to form mass nanoprobes for enhancing the monitoring sensitivity. With the introduction of H2O2 to dissolve the mass nanoprobes attached on sensing interface, a signal recovery QCM strategy is established for real-time and continuous monitoring of three LTBI biomarkers.

Single molecule force spectroscopy for in-situ probing oridonin inhibited ROS-mediated EGF-EGFR interactions in living KYSE-150 cells.

As the active anticancer component of Rabdosia Rubescens, oridonin has been proved to show strong anticancer activity in cancer cells, which is also found to be closely related to its specific inhibition effects on the EGFR tyrosine kinase activity. In this study, atomic force microscopy based single molecule force spectroscopy (AFM-SMFS) was used for real-time and in-situ detection of EGF-EGFR interactions in living esophageal cancer KYSE-150 cells to evaluate the anticancer activity of oridonin for the first time. Oridonin was found to induce apoptosis and also reduce EGFR expression in KYSE-150 cells. AFM-SMFS results demonstrated that oridonin could inhibit the binding between EGF and EGFR in KYSE-150 cells by decreasing the unbinding force and binding probability for EGF-EGFR complexes, which was further proved to be closely associated with the intracellular ROS level. More precise mechanism studies based on AFM-SMFS demonstrated that oridonin treatment could decrease the energy barrier width, increase the dissociation off rate constant and decrease the activation energy of EGF-EGFR complexes in ROS dependent way, suggesting oridonin as a strong anticancer agent targeting EGF-EGFR interactions in cancer cells through ROS dependent mechanism. Our results not only suggested oridonin as a strong anticancer agent targeting EGF-EGFR interactions in ROS dependent mechanism, but also highlighted AFM-SMFS as a powerful technique for pharmacodynamic studies by detecting ligand-receptor interactions, which was also expected to be developed into a promising tool for the screening and mechanism studies of drugs.

Erythrocytes-based quartz crystal microbalance cytosensor for in situ detection of cell surface sialic acid.

An erythrocytes (RBCs) cytosensor was first fabricated for in situ analysis of sialic acid (SA) on the cell surface based on a quartz crystal microbalance (QCM). RBCs, as a recognition element, were immobilized on a concanavalin A (ConA)-modified gold chip through the specific recognition between ConA and mannose on the cell surface. 4-Aminobenzeneboronic acid (APBA)-functionalized gold nanoparticles (AuNPs/APBA) were used as a signal amplification nanoprobe for labeling SA on the surface of RBCs. Compared to that of APBA, the frequency response of the cytosensor could be significantly enhanced 18-fold by using a AuNPs/APBA nanoprobe. RBCs can be detected in the range of 2.6 × 103 to 7.2 × 106 cells per mL with a detection limit of 1.1 × 103 cells per mL. The proposed cytosensor was further applied to detect the expression level of SA on normal and diabetic RBCs in situ, which showed that the average number of SA expressed on single normal and diabetic RBC surfaces were 2.1 ± 0.2 × 108 and 8.2 ± 0.7 × 107 with a relative standard deviation of 4.3% and 3.6%, respectively. The strategy shows an in situ and high sensitivity method for the quantitative evaluation of SA expression on RBC surface and provides a new alternative methodology to analyze glycan expression at the cell surface.

Atomic force microscopy based investigations of anti-inflammatory effects in lipopolysaccharide-stimulated macrophages.

A new method based on atomic force microscopy (AFM) was developed to investigate the anti-inflammatory effects of drugs on lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. The LPS-stimulated RAW264.7 macrophage cell line is a widely used in vitro cell model for the screening of anti-inflammatory drugs or the study of anti-inflammatory mechanisms. In this work, the inhibitory effects of dexamethasone and quercetin on LPS-CD14 receptor binding in RAW264.7 macrophages was probed by LPS-functionalized tips for the first time. Both dexamethasone and quercetin were found to inhibit LPS-induced NO production, iNOS expression, IκBα phosphorylation, and IKKα/ß phosphorylation in RAW264.7 macrophages. The morphology and ultrastructure of RAW264.7 macrophages were determined by AFM, which indicated that dexamethasone and quercetin could inhibit LPS-induced cell surface particle size and roughness increase in RAW264.7 macrophages. The binding of LPS and its receptor in RAW264.7 macrophages was determined by LPS-functionalized AFM tips, which demonstrated that the binding force and binding probability between LPS and CD14 receptor on the surface of RAW264.7 macrophages were also inhibited by dexamethasone or quercetin treatment. The obtained results imply that AFM, which is very useful for the investigation of potential targets for anti-inflammatory drugs on native macrophages and the enhancement of our understanding of the anti-inflammatory effects of drugs, is expected to be developed into a promising tool for the study of anti-inflammatory drugs.

Label-free quartz crystal microbalance with dissipation monitoring of resveratrol effect on mechanical changes and folate receptor expression levels of living MCF-7 cells: a model for screening of drugs.

Quartz crystal microbalance with dissipation (QCM-D) monitoring was used for real-time and label-free detection of changes and folate receptor (FR) expression levels on living MCF-7 cells for evaluating the anticancer activity of resveratrol. Here, the mechanical changes of cellular responses to resveratrol were tracked by a poly(l-lysine) (PLL) modified QCM-D sensor, and the inhibition effect of resveratrol on FR expression levels on MCF-7 cells was monitored by chitosan-folic acid (CS-FA) composite membrane functionalized Au substrate for the first time. Changes in morphology and the cellular state of MCF-7 cells stimulated by resveratrol at different concentrations were detected by inverted fluorescence microscopy and flow cytometry. Atomic force microscopy confirmed that resveratrol influenced the cellular mechanical properties. The results indicated that the MCF-7 cells lose their original elasticity and increase their stiffness induced by resveratrol. It was further observed by confocal fluorescence imaging that resveratrol reduced the FR expression levels on the living cells surface. This study established a typical model of the QCM-D biosensor to evaluate the protein biomarker expression levels on the cells surface. QCM-D, which was used to investigate potential targets for an antitumor drug on living cells and realize a better understanding of the drug action mechanism, was expected to be developed into a promising tool for the screening of drugs.

In situ single molecule detection of insulin receptors on erythrocytes from a type 1 diabetes ketoacidosis patient by atomic force microscopy.

Type 1 diabetes is an insulin-dependent metabolic disorder always associated with ketoacidosis and a high morbidity rate in teenagers. The in situ single molecule detection of insulin receptors on healthy and diseased erythrocytes is helpful to understand the pathomechanism of type 1 diabetes ketoacidosis (T1-DKA), which would also benefit the diagnosis and treatment of T1-DKA. Here, we demonstrated, for the first time, the single molecule interaction between insulin and insulin receptor on erythrocytes from a healthy volunteer and a T1-DKA patient using high sensitivity atomic force microscopy (AFM) in PBS solution. The single molecule force results demonstrated the decreased binding force and binding probability between insulin and insulin receptor on T1-DKA erythrocytes, implying the deficit of insulin receptor functions in T1-DKA. The binding kinetic parameters calculated from dynamic force spectroscopy indicated that the insulin-insulin receptor complexes on T1-DKA erythrocytes were less stable than those from healthy volunteer. Using high resolution AFM imaging, a decreased roughness was found both in intact T1-DKA erythrocytes and in the purified membrane of T1-DKA erythrocytes, and an increased stiffness was also found in T1-DKA erythrocytes. Moreover, AFM, which was used to investigate the single molecule interactions between insulin-insulin receptor, cell surface ultrastructure and stiffness in healthy and diseased erythrocytes, was expected to develop into a potential nanotool for pathomechanism studies of clinical samples at the nanoscale.

A novel strategy for real-time and in situ detection of cytochrome c and caspase-9 in Hela cells during apoptosis.

Cytochrome c (cyt c) and caspase-9 were critical biomarkers in mitochondria-mediated apoptosis. A novel electrochemical immunosensor was developed for in situ analysis of cyt c and caspase-9 in the cytosol. Gold nanoparticle-polydopamine (AuNP/PDA) composites were used to fabricate the interface of the sensor. The anti-cyt c or anti-caspase-9 functionalized-immunosensor provided a biomimetic interface for immunosensing of cyt c or caspase-9 in Hela cells during apoptosis. The changes in the expression level of cyt c and caspase-9 in the cytosol upon curcumin-induced apoptosis were detected by using the proposed method, and also the influence of different concentrations and incubation times of curcumin-induced Hela cells was investigated. This method achieved a linear range (0.1-100 µM) for standard cyt c and caspase-9, with a detection limit of 0.03 ± 0.01 µM for standard cyt c and 0.08 ± 0.02 µM for standard caspase-9. Moreover, this method was used to detect cells which could detect as low as 100 cells which expressed cyt c and caspase-9, and also the results are in good agreement with standard flow cytometry analysis. The developed electrochemical immunosensor offered a simple and rapid approach for sensitive evaluation of apoptosis markers with considerable specificity and reproducibility, and also the developed strategy could be of great importance in clinical diagnosis and therapeutic research.

A recyclable chitosan-based QCM biosensor for sensitive and selective detection of breast cancer cells in real time.

A highly sensitive and recyclable quartz crystal microbalance (QCM) biosensor was developed using chitosan (CS) and folic acid (FA), generating conjugates that are selectively recognized by MCF-7 cancer cell over-expressed folic acid receptors. The prepared CS-FA conjugate was characterized by UV-vis spectroscopy and Fourier transform infrared spectroscopy. Atomic force microscopy and scanning electron microscopy further presented the morphology of the CS-FA conjugate interface. The hydrophilicity of films was characterized by measuring the contact angle. The recognition of MCF-7 cancer cells was investigated in situ using QCM. Captured by FA, the concentration of the MCF-7 cell was determined on-line using a quartz crystal microbalance and a wide linear range of 4.5 × 10(2) to 1.01 × 10(5) cells per mL was obtained, with a detection limit of 430 cells per mL. The fluorescence microscope further confirmed the specificity and biocompatibility of the constructed biosensor. In addition, the regeneration of the QCM biosensor was studied by using lysozyme. This receptor-bound ligand based QCM biosensor also showed good selectivity, and repeatability in the cell mixture. For the first time, this simple, economical and label-free chitosan-based QCM sensing was demonstrated, and such design could provide a promising detection strategy for sensitive detection of cancer cell over-expressed folic acid receptors.

An efficient nanomaterial-based electrochemical biosensor for sensitive recognition of drug-resistant leukemia cells.

A novel electrochemical cytosensor was developed for the fast and high-sensitivity recognition of drug-resistant leukemia K562/ADM cells based on the P-glycoprotein (P-gp) expression level on a cell membrane. The nanocomposite interface of the gold nanoparticles/polyaniline nanofibers (AuNPs/PANI-NF) was chosen to design the biosensor for electrochemical detection. Au/PANI-NF-based cytosensors coated with anti-P-glycoprotein (anti-P-gp) molecules could provide a biomimetic interface for the immunosensing of cell surface P-glycoprotein, and thus could capture the over-expression P-gp cells. Transmission electron microscopy (TEM) indicated that the gold nanoparticles were uniformly anchored along the structure of the PANI-NF surface, displaying fibrillar morphology with a diameter of ∼70 nm, and atomic force microscopy (AFM) further presented the morphology of the nanocomposite film. Owing to the high affinity of anti-P-gp for leukemia K562/ADM cells of the propounded sensing platform, the proposed biosensor exhibited excellent analytical performance for leukemia K562/ADM cells, ranging from 1.6 × 10(2) to 1.6 × 10(6) cells per mL with a detection limit of 80 cells per mL. Recovery experiments indicated that the sensitivity reported here is suitable for practical application. The cell surface P-gp expression level was analysed by flow cytometric experiments, which confirmed the above recognized result. This strategy is also a cost-effective and convenient operation, implying great promise for the sensitive recognition of cancer cells and cell surface receptors; thus, it is helpful in cancer diagnosis.

Synthesis and synergetic anti-tumor activity evaluation of dihydroartemisinin-organogermanium(IV) compound.

Dihydroartemisinin (DHA), a semi-synthetic derivative of the herb artemisinin, has shown commendable bioactivity. In this paper, a novel dihydroartemisinin-organogermanium (DHA-Ge) compound was synthesized, characterized and its potential anti-tumor activity was evaluated by various methods. MTT results demonstrated that DHA-Ge could effectively inhibit the proliferation of HepG2 cells and showed their dose-dependent properties. The IC50 value of inhibition effect on HepG2 cells of DHA-Ge was 10.23 µg/ml which was lower than 39.44 µg/ml of DHA. Flow cytometric results suggested that DHA-Ge could induce apoptosis of HepG2 cells and the apoptosis rate was 20.26% after 24h treatment with 56.8 µg/ml DHA-Ge concentration. Atomic force microscopy images showed that HepG2 cells were collapsed and the cell nucleus were fragmented after 24h treatment. All these results together showed that the DHA-Ge possessed desirable synergetic enhanced anti-tumor effects and could be developed as a suitable tumor therapeutic agent.

Synthesis and synergetic effects of chrysin-organogermanium (IV) complex as potential anti-oxidant.

Organogermanium(IV) (Ge) is considered to play an important role in the anti-oxidative activities of some Chinese medicines. Here, a new chrysin-organogermanium (Chry-Ge) complex was synthesized and investigated for its potential biological activities. The radicals-sensitive Ge-O bond was introduced to Chry-Ge complex to enhance bioactivities of organic Ge or Chry. Results showed that Chry-Ge complex possessed great anti-oxidative activities, showing stronger hydroxyl scavenging effects than their corresponding ligands. We also demonstrated Chry-Ge complex inhibited ROS-dependent oxidative damage in cells. Moreover, the morphological and biophysical recoveries in oxidation-damaged cells induced by Chry-Ge complex were characterized by atomic force microscopy. All these results collectively suggested that Chry-Ge complex has synergetic effect for radicals scavenging and could be served as promising pharmacologically active agent against anti-oxidative treatment.

Synthesis and biological evaluation of Germanium(IV)-polyphenol complexes as potential anti-cancer agents.

Germanium (Ge) is considered to play a key role in the pharmacological effects of some medicinal plants. Here, two new Ge(IV)-polyphenol complexes were synthesized and measured for their potential biological activities. The results indicated that these Ge(IV)-polyphenol complexes possessed great anti-oxidative activities, both showing stronger hydroxyl scavenging effects than their corresponding ligands. We also demonstrated the strong intercalating abilities of Ge(IV)-polyphenol complexes into calf thymus-DNA molecules. In addition, these two Ge(IV)-polyphenol complexes showed strong proliferative inhibition effect on HepG2 cancer cells. Moreover, the morphological changes in HepG2 cells induced by Ge(IV)-polyphenol complexes were detected by atomic force microscopy. All these results collectively suggested that Ge(IV)-polyphenol complexes could be served as promising pharmacologically active substances against cancer treatment.