Yanchuan Guo

Bovine Collagen Peptides Compounds Promote the Proliferation and Differentiation of MC3T3-E1 Pre-Osteoblasts

Objective Collagen peptides (CP) compounds, as bone health supplements, are known to play a role in the treatment of osteoporosis. However, the molecular mechanisms of this process remain unclear. This study aimed to investigate the effects of bovine CP compounds on the proliferation and differentiation of MC3T3-E1 cells. Methods Mouse pre-osteoblast cell line MC3T3-E1 subclone 4 cells were treated with bovine CP compounds. Cell proliferation was analyzed by MTT assays and the cell cycle was evaluated by flow cytometry scanning. Furthermore, MC3T3-E1 cell differentiation was analyzed at the RNA level by real-time PCR and at the protein level by western blot analysis for runt-related transcription factor 2 (Runx2), a colorimetric p-nitrophenyl phosphate assay for alkaline phosphatase (ALP), and ELISA for osteocalcin (OC). Finally, alizarin red staining for mineralization was measured using Image Software Pro Plus 6.0. Results Cell proliferation was very efficient after treatment with different concentrations of bovine CP compounds, and the best concentration was 3 mg/mL. Bovine CP compounds significantly increased the percentage of MC3T3-E1 cells in G2/S phase. Runx2 expression, ALP activity, and OC production were significantly increased after treatment with bovine CP compounds for 7 or 14 days. Quantitative analyses with alizarin red staining showed significantly increased mineralization of MC3T3-E1 cells after treatment with bovine CP compounds for 14 or 21 days. Conclusions Bovine CP compounds increased osteoblast proliferation, and played positive roles in osteoblast differentiation and mineralized bone matrix formation. Taking all the experiments together, our study indicates a molecular mechanism for the potential treatment of osteoarthritis and osteoporosis.

Fabrication of ZnO composite microfibers for near-infrared light mediated photocatalysis

The fabrication of photocatalysts driven by near‐infrared (NIR) light is of great scientific and technological interest to make use of solar energy. NaYF4 codoped with Yb3+ and Tm3+ upconversion nanoparticles are important nanotransducers that transfer NIR photons to high‐energy photons (UV/Vis). In this work, we demonstrated an electrospinning technique to synthesize ZnO and porous ZnO composite microfibers embedded with a large amount of NaYF4:Yb/Tm@NaYF4 nanoparticles. The morphologies, chemical compositions, and phase of the as‐prepared composites were investigated carefully by using field‐emission scanning electron microscopy, TEM, X‐ray photoelectron spectroscopy, fluorescence spectroscopy, and XRD. Steady‐state and dynamic‐state fluorescence spectra were used to demonstrate that the embedded NaYF4:Yb/Tm@NaYF4 core–shell nanoparticles can activate the ZnO nanoparticles under IR irradiation. The ZnO composite microfibers can efficiently transfer the NIR photons to the excited state of ZnO and activate the semiconductor to produce reactive oxygen species to result in the degradation of rhodamine B dyes.

Novel nanoparticle-assembled Bi12GeO20 hierarchical structures: facile hydrothermal synthesis and excellent photocatalytic activity

The hydrothermal synthesis strategy is being widely applied to the preparation of various inorganic nano- or micro-structures due to its facile and mild reaction environment that allows effective control of the morphologies and phases of the products. Through careful modulation of the hydrothermal synthesis reaction conditions, we have successfully fabricated novel nanoparticle-assembled Bi12GeO20 hierarchical structures whose morphology, phase and size can be adjusted, confirmed with various testing techniques including powder X-ray diffraction (XRD), FT-IR spectrum, X-ray photoelectron spectrum (XPS), energy dispersive spectrometry (EDS), selected area electron diffraction (SAED), high resolution transmission electron microscopy (HRTEM) and scanning electron microscopy (SEM). Furthermore, the effect of some factors such as synthesis temperature, time, the mass of sodium carboxymethyl cellulose, the type and amount of mineralizing agent on the morphologies and phases of the samples are systematically studied. On the basis of abundant experimental facts, a probable formation process is presented. The photocatalytic activity of the as-obtained Bi12GeO20 hierarchical structures was also investigated, which exhibited remarkable photocatalytic performance for the degradation of rhodamine B (RhB).

Decoration of upconversion nanoparticles@mSiO2 core–shell nanostructures with CdS nanocrystals for excellent infrared light triggered photocatalysis

In this work, we demonstrate a facile process to synthesize upconversion nanoparticles (UCNPs)@mesoporous SiO2 (mSiO2) core–shell nanoparticles decorated with CdS nanoparticles. The size and morphology of the as-prepared products have been investigated carefully; which show that the UCNPs and CdS nanoparticles are ca. 50 and 5 nm in diameter, respectively, and the mesoporous silica layer is 10 nm in thickness. The fluorescence spectra of the as-prepared UCNPs@mSiO2/CdS nanoparticles show that the fluorescence emissions (380, 451 and 470 nm) have been greatly quenched via energy transitions from the UCNPs nanoparticles (donors) to the CdS nanoparticles (acceptors). CdS nanoparticles were activated by the UCNPs to produce photo-generated ˙OH radicals under irradiation of infrared (IR) light. Photodegradation towards RhB dyes was studied to demonstrate the photocatalytic properties for the as-prepared UCNPs@mSiO2/CdS nanoparticles under irradiation of near infrared light. The as-designed nanostructures of UCNPs@mSiO2/CdS nanoparticles show excellent photocatalytic performance on photodegradation towards RhB under irradiation of infrared light. This kind of nanostructure may find potential applications in photodynamic therapy of cancer cells, for use as nanotransducers, in dyed sensitized solar cells etc.

N-Doped biochar derived from co-hydrothermal carbonization of rice husk and Chlorella pyrenoidosa for enhancing copper ion adsorption

Biochar derived from rice husk was modified by microalgae Chlorella pyrenoidosa as a natural nitrogen-rich precursor in a hydrothermal environment for copper ion (Cu(II)) adsorption. Pristine biochar derived from hydrothermal carbonization of individual rice husks was included as a control. FTIR, SEM and BET analyses indicated that the modified biochar is more hydrophobic and basic than the pristine biochar due to the anchoring of surface nitrogenous functionalities. The adsorption of copper ions onto the pristine and modified biochar was investigated with respect to pH, adsorbent dosage, contact time, temperature, kinetics and isotherms. The results showed that modification of the biochar by nitrogen significantly increased the copper adsorption capacity from 13.12 mg g−1 for the pristine biochar to 29.11 mg g−1 for the modified biochar. Adsorption of copper ions by the modified biochar was dominated by surface complexation rather than through the electrostatic attractions that dominated adsorption for the pristine biochar.

The effect of different molecular weight collagen peptides on MC3T3-E1 cells differentiation

Our study aimed at investigating the effect of different molecular weight bovine collagen peptides, namely CH878, CH1370, CH2900, and CH7747 on the differentiation of MC3T3-E1 cells. Osteogenic differentiation of MC3T3-E1 cells was assessed by a series of specific assays, after culturing of cells in the presence of collagen peptides. Alkaline phosphatase activity (ALP) was evaluated by NBT/BCIP staining. Osteocalcin expression was determined by a radioimmunology method. Mineralization was quantified by Alizarin Red staining. ALP staining results demonstrated that the ALP staining of cells after culture in the presence of collagen peptides were significantly higher than the control group (P<0.05), indicating the promotion of ALP activity in MC3T3-E1 cells by these peptides. Radioimmunology results demonstrated that collagen peptides groups were all significantly higher than the control group (P<0.01). Alizarin Red staining results demonstrated that CH1370, CH2900, and CH7747 significantly promoted the formation of mineralized bone matrix. We therefore conclude that CH1370, CH2900, and CH7747 play an active role in the differentiation of MC3T3-E1 cells. Based on the above results, we provide molecular basis for further development of collagens with different molecular weight for the prevention and treatment of osteoporosis.

Combined oral administration of bovine collagen peptides with calcium citrate inhibits bone loss in ovariectomized rats.

Purpose Collagen peptides (CPs) and calcium citrate are commonly used as bone health supplements for treating osteoporosis. However, it remains unknown whether the combination of oral bovine CPs with calcium citrate is more effective than administration of either agent alone. Methods Forty 12-week-old Sprague-Dawley rats were randomly divided into five groups (n = 8) for once-daily intragastric administration of different treatments for 3 months at 3 months after ovariectomy (OVX) as follows: sham + vehicle; OVX + vehicle; OVX + 750 mg/kg CP; OVX + CP-calcium citrate (75 mg/kg); OVX + calcium citrate (75 mg/kg). After euthanasia, the femurs were removed and analyzed by dual energy X-ray absorptiometry and micro-computed tomography, and serum samples were analyzed for bone metabolic markers. Results OVX rats supplemented with CPs or CP-calcium citrate showed osteoprotective effects, with reductions in the OVX-induced decreases in their femoral bone mineral density. Moreover, CP-calcium citrate prevented trabecular bone loss, improved the microarchitecture of the distal femur, and significantly inhibited bone loss with increased bone volume, connectivity density, and trabecular number compared with OVX control rats. CP or CP-calcium citrate administration significantly increased serum procollagen type I N-terminal propeptide levels and reduced serum bone-specific alkaline phosphatase, osteocalcin, and C-telopeptide of type I collagen levels. Conclusions Our data indicate that combined oral administration of bovine CPs with calcium citrate inhibits bone loss in OVX rats. The present findings suggest that combined oral administration of bovine CPs with calcium citrate is a promising alternative for reducing bone loss in osteopenic postmenopausal women.

Selective protein complexation and coacervation by polyelectrolytes

This review discusses the possible relationship between protein charge anisotropy, protein binding affinity, polymer structure, and selective phase separation. We hope that a fundamental understanding of primarily electrostatically driven protein-polyelectrolyte (PE) interactions can enable the prediction of selective protein binding, and hence selective coacervation through non-specific electrostatics. Such research will partially challenge the assumption that specific binding has to be realized through specific binding sites with a variety of short-range interactions and some geometric match. More specifically, the recent studies on selective binding of proteins by polyelectrolytes were examined from different assemblies in addition to the electrostatic features of proteins and PEs. At the end, the optimization of phase separation based on binding affinity for selective coacervation and some considerations relevant to using PEs for protein purification were also overviewed.

Controlled synthesis of porous Co3O4 nanofibers by spiral electrospinning and their application for formaldehyde oxidation

Nanofiber mats have been widely used in various fields owing to their high porosity, high specific area and three-dimensional architecture. Porous cobaltosic oxide (Co3O4) nanofiber mats were mass-produced by spiral electrospinning and controlled calcination, after which the three-dimensional scaffold still existed and consisted of well-twisted continuous nanofibers. The nanofiber was composed of neat Co3O4 nanoparticles with a necklace-like arrangement. The mechanism for the formation of porous Co3O4 necklaces was proposed by investigating the structural evolution of the calcined fibers, their elemental composition, crystal structure and the presence or absence of different functional groups. Moreover, the porous Co3O4 nanofiber mats exhibited high catalytic activity (98 °C, 100% conversion) and catalytic stability (160 h, nearly 100% conversion) for the oxidation of formaldehyde, which was mostly attributed to the increases in the porosity and the specific area.

Biodegradable Gelatin/beta-Tricalcium Phosphate Composite Microspheres As Localized Delivery of Growth Factor- Velvet Antler Polypeptides by Water-in-Oil (W/O) Emulsion Process

This work introduce a new conventional method to prepare ternary composite moicrospheres nano beta-tricalcium phosphate/ gelatin/ velvet antler polypeptides by water-in-oil (W/O) emulsion process. The nano beta-tricalcium phosphate (TCP) and velvet antler polypeptides (VAP) are embedded into the gelatin spheres. SEM image indicates the composite spheres have a homogeneous microstructure, a perfect monodispersity and also a uniform size of about 45 mum. The optical microscopy picture shows the nano TCP granules are embedded inside the composite. From the SELDI-TOF-MS spectrum, it can be seen that the VAP is brought into the inside of the spheres by the same emulsion process. In the reaction, the growth factor through ion complex binds to the gelatin matrix by the different isoelectric point (IEP) of gelatin (8.5) and VAP (4.5). DSC-TGA image illustrates the 90% TCP is embedded inside the gelatin spheres through the emulsion process and strong interaction appeared between TCP and gelatin that come from the calcium ions from the TCP and the carboxyl ions from gelatin.