HIF1α/VEGF Feedback Loop Contributes to 5-Fluorouracil Resistance.

5-Fluorouracil (5-Fu) is one of the basic drugs in colorectal cancer (CRC) chemotherapy, and its efficacy is mainly limited by the acquisition of drug resistance. However, the underlying mechanisms remain unclear. In this study, hypoxia inducible factor 1α (HIF1α) was screened for high expression in 5-Fu resistant HCT115 cells, which displayed epithelial-mesenchymal transition (EMT) phenotype. Suppression of HIF1α reversed EMT phenotype, reduced glucose transporter 1 (Glut1) expression, a key molecule mediated drug resistance. Moreover, we unveiled that vascular endothelial growth factor (VEGF) was regulated by HIF1α and mediated HIF1α-maintained malignant phenotype of 5-Fu resistant cells. Further studies verified that AKT/GSK3ß signaling was activated in resistant cells and controlled HIF1α expression. Interestingly, we demonstrated that VEGF could feedback up-regulate HIF1α via AKT/GSK3ß signaling. Clinically, HIF1α and VEGF were high expressed and associated with survival and prognosis in CRC patients. In conclusion, our findings proposed that HIF1α/VEGF feedback loop contributed to 5-Fu resistance, which might be potential therapeutic targets.

A Predictive Model for the Risk of Cognitive Impairment in Patients with Gallstones.

OBJECTIVES: Gallstones can cause malnutrition in patients and further lead to cognitive impairment. This study is aimed at constructing a validated clinical prediction model for evaluating the risk of developing cognitive impairment from gallstones. METHODS: The study was a single-centre crosssectional study. Four models or methods (SVM-RFE, random forest model, Lasso model, and logistics analysis) were analyzed and compared regarding their predictive performance. The model with the best classification performance and predictive power was selected. The AUC index, C-index, and calibration curves were applied to the chosen model to further evaluate its classification and prediction performance. Finally, the nomogram was plotted, and the clinical usability, efficacy, and safety of the nomogram were assessed using decision curve analysis (DCA). RESULTS: This study included a total of 294 patients with gallstones, of which 110 had cognitive impairment. Factors such as gender, age, education, place of birth, history of alcohol consumption, abdominal circumference, sarcopenia, diabetes, anaemia, depression, and Pittsburgh Sleep Quality Index (PSQI) were incorporated into the model for nomogram construction. The calibration curve showed that the nomogram had good classification performance. Furthermore, the C-index of the model was 0.778 (95% CI, 0.674-0.882) in the test group. The DCA curves indicated that the constructed model had strong clinical applicability, efficacy, and safety. CONCLUSIONS: This study constructed a cognitive impairment risk prediction model for patients with gallstones with good classification and predictive power. The constructed predictive model allows us to screen patients with gallstones and at high risk of cognitive impairment. These efforts might also help to further increase patient compliance, assist healthcare professionals to better manage patients with gallstones, and ultimately improve their overall health status and quality of life. Future clinical studies should further evaluate the accuracy and clinical usability of this model.

Application of functional microsphere in human hepatitis B virus surface antigen detection.

A novel and simple emulsifier-free emulsion polymerization technique was developed for preparation of mono-dispersed amino functionalized polymer microspheres with well defined diameters (about 400 nm). Various characterization methods demonstrated that the obtained amino microspheres had a uniform size and good dispersity which were confirmed by scanning electron microscope (SEM). Zeta potential and Fourier transform infrared spectrometer (FT-IR) demonstrated that amino groups have been successfully introduced to the microsphere surface. These functionalized microspheres have been shown to be efficient and controllable carriers capable of immobilizing and enriching monoclonal antibodies. Moreover, a newest chemiluminescent enzyme-linked immunoassay (ELISA) approach has been developed for human Hepatitis B virus surface antigen (HBsAg) detection. HBsAg was sandwiched between goat anti-HBsAg polyclonal antibody and mouse anti-HBsAg antibody. Alkaline phosphatase (ALP) conjugated horse anti-mouse immunnogloblin was used to bond with monoclonal antibody. Finally, chemiluminesent (CL) signals were recorded after adding 3-(2-spiroadamantane)-4-methoxy-4-(3-phosphoryloxy) phenyl-1,2-dioxetane (AMPPD) which was used as a chemiluminescent substrate reagent of ALP. This novel chemiluminescent ELISA assay was proved to be of excellent specificity and high sensitivity when using ALP and AMPPD luminescence systems for specific HBsAg detection.

Influence of nanoparticle shape, size, and surface functionalization on cellular uptake.

With the rapid development of biotechnology and nanomedicine, extensive research has focused on the investigations of delivering large-cargo molecules using nanoparticles through the cell membrane for disease diagnosis and treatment. Various inorganic and polymeric nanoparticles with optimized surface properties have been developed to carry these active cargo molecules such as organic molecules, oligonucleotides and proteins. Phagocytosis and pinocytosis have been suggested as the two major uptake mechanisms for nanoparticles to enter into cellular interior, but such mechanisms are still under debate. In order to enhance the efficiency of cellular uptake of nanoparticles and further understand the physiological process, it is important to investigate detailed interaction mechanisms between nanoparticles and cell membranes. Here, we will review the recent advances of the effect of nanoparticle properties (e.g., nanoparticle shape, size, charge, surface modification, etc.) on cellular uptake mechanisms. These will aid in the future design and development of nanoparticles with improved surface properties for drug and biomolecule delivery. Up to now, novel analytical techniques have been used to examine nanoparticle-cell membrane interactions, but their detailed uptake mechanisms and pathways still need more in-depth research. It is suggested that developing appropriate analytical techniques to study cellular uptake mechanisms of nanoparticles in real time is urgently desired.

Chemiluminescence analysis for HBV-DNA hybridization detection with magnetic nanoparticles based DNA extraction from positive whole blood samples.

Molecular detection of HBV has a significant impact on prognosis and therapy of the disease. In this paper, a sensitive nucleic acid detection method of HBV was established taking advantage of magnetic nanoparticles (MNPs), chemiluminescence (CL) and polymerase chain reaction (PCR). HBV-DNA was extracted from hepatitis B positive human blood samples using MNPs adsorption method and biotin was labeled on the DNA segment after base insertion of bintin-dUTP in PCR. The biotinylated DNA segment was captured by amino probe immobilized on carboxyl MNPs and was detected by the chemiluminescence system of alkaline phosphatase catalyzing 3-(2'-spiroadamantane)-4-methoxy-4-(3"-phosphoryloxy) phenyl-1, 2-dioxetane. Different concentrations of HBV-DNA were detected under the optimized experiment conditions and the relevant CL intensity were obtained, which provided a novel research or clinic diagnosis method for the quantification detection of HBV-DNA.

Preparation of functional magnetic nanoparticles mediated with PEG-4000 and application in Pseudomonas aeruginosa rapid detection.

A rapid detection method of Pseudomonas aeruginosa based on magnetic separation and chemiluminescence was developed in this paper. Magnetic nanoparticles (MNPs) were prepared by solvothermal method with PEG-4000 as a surfactant, and then were modified. The prepared MNPs present a uniform morphology and good dispersion. The sizes of MNPs can be controlled by adjusting the dosage of FeCl3 x 6H2O. The obtained particles were characterized with Scanning electron microscope (SEM), Transmission electronic microscopy (TEM) and Fourier transform infrared (FTIR). The biotin-dUTP-labeled DNA fragments of gyrB gene were amplified by polymerase chain reaction (PCR), and Pseudomonas aeruginosa was successfully detected with detection limit as low as 7.5 fM of gyrB fragments.

Improvement on controllable fabrication of streptavidin-modified three-layer core-shell Fe3O4@SiO2@Au magnetic nanocomposites with low fluorescence background.

In present study, we put forward an approach to prepare three-layer core-shell Fe3O4@SiO2@Au magnetic nanocomposites via the combination of self-assembling, seed-mediated growing and multi-step chemical reduction. The Fe3O4@SiO2@Au magnetic nanocomposites were analyzed and characterized by transmission electron microscope (TEM), scanning electronic microscope (SEM), energy dispersive spectrometer analysis (EDS), Fourier transform infrared spectroscopy (FT-IR), vibrating sample magnetometer (VSM), and ultraviolet and visible spectrophotometer (UV-Vis). TEM and SEM characterizations showed that the FeO4@SiO2@Au nanocomposites were obtained successfully with three-layer structures, especially a layer of thin, smooth and continuous gold shell. The average diameter of Fe3O4@SiO2@Au nanocomposites was about 600 nm and an excellent dispersity was observed for the as-prepared nanoparticles. EDS characterizations demonstrated that the nanocomposites contained three elements of the precursors, Fe, Si, and Au. Furthermore, FT-IR showed that the silica and gold shell were coated successfully. UV-Vis and VSM characterizations showed that the Fe3O4@SiO2@Au nanocomposites exhibited good optical and magnetic property, and the saturation magnetization was 25.76 emu/g. In conclusion, the Fe3O4@SiO2@Au magnetic nanocomposites with three-layer core-shell structures were prepared. Furthermore, Fe3O4@SiO2@Au magnetic nanocomposites were modified with streptavidin (SA) successfully, and it was validated that they performed low fluorescence background, suggesting that they should have good applications especially in bioassay based on fluorescence detection through bonding the biotinylated fluorescent probes.

Magnetic nanoparticles-based extraction and verification of nucleic acids from different sources.

In many molecule biology and genetic technology studies, the amount of available DNA can be one of the important criteria for selecting the samples from different sources. Compared with those genomic DNA methods using organic solvents or other traditional commercial kits, the method based on magnetic nanoparticles (MNPs) and adsorption technology has many remarkable advantages like being time-saving and cost effective without the laborious centrifugation or precipitation steps, and more importantly it has the great potential and especially suitable for automated DNA extraction and up-scaling. In this paper, the extraction efficiency of genomic nucleic acids based on magnetic nanoparticles from four different sources including bacteria, yeast, human blood and virus samples are compared and verified. After measurement and verification of the extracted genomic nucleic acids, it was shown that all these genomic nucleic acids extracted using the MNPs method can be of high yield and be available for next molecule biological steps.

Preparation and characterization of monodisperse core-shell Fe3O4@SiO2 microspheres and its application for magnetic separation of nucleic acids from E. coli BL21.

In this article, we present an easy route to prepare monodisperse core-shell Fe3O4@SiO2 microspheres with uniform size and shape. Their structures and properties were studied by transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared spectrometry (FT-IR), and vibrating sample magnetometer (VSM), respectively. The results showed that spherical Fe3O4 microspheres with well dispersion have a rough surface and an average diameter (about 500 nm). After the modification with silica, the particles have a well-defined core-shell structure and a much smoother surface and larger particle diameter (about 600 nm). Furthermore, VSM measurements indicated that the as-prepared Fe3O4 and Fe3O4@SiO2 microspheres were superparamagnetic at room temperature and the saturation magnetization (M(s)) were 58.110 emu/g and 33.479 emu/g, respectively. And then, the prepared monodisperse core-shell Fe3O4@SiO2 microspheres were subsequently applied to separate nucleic acids from the bacteria (E. coli BL21) and verified the great application prospects for bioseparation technology of the biomoleculars.

Preparation and biomedical applications of core-shell silica/magnetic nanoparticle composites.

Core-shell structured silica/magnetic nanoparticle composites have recently been subjected to extensive research since the shells could offer protection to the cores and introduce new properties to the hybrid structures, which endue them with great application potentials in various fields. Several approaches have been studied for the synthesis of SiO2 coated on magnetic nanoparticles. These approaches include Stöber process, microemulsion, sodium silicate and tetraethoxysilane hydrolysis, aerosol pyrolysis, layer-by-layer strategy, polymer-templating and sonochemical deposition. This review is focused on describing state-of-the-art synthetic routes and methods for the preparation of silica/magnetic nanoparticle composites. Furthermore, we also introduce main applications of these nanoparticle composites in biomedical scopes and address some challenges in the synthesis of high-quality magnetic nanoparticles.

Chemiluminescence molecular detection of sequence-specific HBV-DNA using magnetic nanoparticles.

Hepatitis B virus is a kind of DNA virus which can cause serious epidemic disease. The analysis and detection of sequence-specific DNA have great significance in forensic analysis, early-stage identification and treatment of genetic disorders. Chemiluminescent detection of DNA has been applied in many fields, such as biological technology and molecular biology, due to its simple operation and high sensitivity. On the other hand, owing to possessing easy magnetic separation and large surface properties, magnetic nanoparticles have also been employed as special carriers to immobilize biomolecules. In this paper, the magnetic nanoparticles are prepared by soft-template method with uniform shape and good dispersion. Then a detection method of hepatitis B virus DNA is established taking advantages of both chemilumiescence with the system of alkaline phosphatase catalyzing 3-(2'-spiroadamantane)- 4-methoxy-4-(3"-phosphoryloxy) phenyl-1, 2-dioxetane and magnetic nanoparticles. The optimization of conditions affecting the hybridization reaction and the chemilumiescence detection are also investigated to promise a high sensitivity.