Oligopeptide T2, a kind of PA (Peptide Amphiphile) molecule, which could build up nano-fiber by self-assembly was designed and synthesized in this study. And the double-diffusion gel system was applied on this molecule to investigate its biomineralization features in vitro. The results showed that T2 could obviously reduce the hydroxyapatite (HA) formation period. And HA was found to possess the characteristics of non-crystalline by analysis of X-ray diffraction (XRD) and scanning electronic microscopy (SEM). These findings point to the conclusion that the negatively charged zone in T2 might make this molecule have the function of promoting HA biomineralization in vitro. And the mechanism responsible for the procession of HA biomineralization needs further research.
Biocompatible Materials ; chemical synthesis ; chemistry ; Bone Substitutes ; chemistry ; Calcification, Physiologic ; Durapatite ; chemistry ; Oligopeptides ; chemical synthesis ; chemistry

Acetates ; chemistry ; Aminopyridines ; chemistry ; Angiogenesis Inhibitors ; chemistry ; Benzodiazepinones ; chemistry ; Humans ; Integrin alphaVbeta3 ; antagonists & inhibitors ; chemistry ; Ligands ; Molecular Structure ; Oligopeptides ; chemistry ; Peptides, Cyclic ; chemistry

In this study for exploring the effect of RGD peptide on adhesive stability of endothelial cells biomaterial surface, all materials were divided into three groups, RGD group (PET covalently grafted synthetic RGD peptides), control group (PET precoated with fibronectin) and blank group (Non-coated surface). Cultured human umbilical vein endothelial cells (HUVECs) were seeded on the materials, then adhesive stability of HUVECs on the varied PET surfaces was observed under steady flow condition, and effects of shear stress and shear time on adherent cells were compared. The results showed that the resistance adherent endothelial cells to detachment by flow was shear stress and shear time dependent. Comparison three groups under the same condition revealed that the ECs retention rates of RGD-grafted or fibronectin-coated group were much higher than that of the non-coated group. Under 8.19 dyne/cm2 shear stress after 4h, retention rates were 13.73% (blank group), 43.33% (RGD group) and 40.75% (control group) respectively. These data indicated that RGD peptide can improve the adhesive stability of endothelial cell on biomaterial and the effect of RGD in vivo needs further studies.
Biocompatible Materials ; chemistry ; Cell Adhesion ; Human Umbilical Vein Endothelial Cells ; cytology ; Humans ; Oligopeptides ; chemistry ; Polyethylene Terephthalates ; chemistry ; Stress, Mechanical

Based on the principle of non-covalent interactions between oligopeptides and paclitaxel for improving the solubility of paclitaxel, an oligopeptide, N terminal-W(L)-FFGREKD-C terminal (W8), was designed and the solubilization effect of W8 on paclitaxel was detected through experiments. The binding efficiency and the possible optimal conformation were optimized by molecular docking program. The solubilization effect of W8 on paclitaxel was determined by RP-HPLC. And the solubilization mechanism of oligopeptide to paclitaxel was proposed at molecular level. It was indicated from the docking result that there existed pi-pi interactions and several hydrogen-bond interactions between the oligopeptide and paclitaxel. After being solubilized by the oligopeptide, the aqueous solubility of paclitaxel was increased to 28 times. This study provided basis for further research of the solubilization of paclitaxel by oligopeptide and confirmed a novel approach for the design of safe oligopeptide solubilizing excipient.
Antineoplastic Agents, Phytogenic ; chemistry ; Drug Design ; Molecular Docking Simulation ; Oligopeptides ; chemistry ; Paclitaxel ; chemistry ; Protein Binding ; Solubility ; Temperature

Snake venom proteins,particularly from the viper and elapid families, have been known to contain a number of platelet active components including what cause platelet aggregation or inhibit platelet aggregation. Some of them have potential clinical usefulness for the treatment of human hemorrhagic or thrombotic disease. Agkistrodon halys pallas belonging to viper family is only growing in China. The aim of this study was to purify a human platelet aggregation inhibitor from venom of Agkistrodon halys pallas and determine its biochemical character. Whether a component could inhibit human platelet aggregation was act as a method to follow the tracks of the protein. Crude venom of Agkistrodon halys pallas was loaded onto a DEAE-Sepharose CL-6B chromatography column could gain 6 peaks. A platelet inhibitor with molecular mass of 65 kD on SDS-PAGE, was purified from peak 2 by Sephadex G-75 gel filtration and SP-Sepharose, Mono Q on FPLC. It could inhibit human platelet aggregation induced by ADP, collagen without activities of phospholipase A2, esterase, fibrinogenolytic. It is concluded that a platelet inhibitor can be isolated and purified from venom of Agkistrodon halys pallas and its inhibition of platelet aggregation is does-dependent.
Crotalid Venoms ; analysis ; Humans ; Oligopeptides ; chemistry ; Platelet Aggregation ; drug effects ; Platelet Aggregation Inhibitors ; isolation & purification

Objective: To analysis the biomechanical and biocompatible properties of calcium phosphate cement (CPC) enhanced by chitosan short nanofibers(CSNF) and Arg-Gly-Asp (RGD). Methods: Chitosan nanofibers were prepared by electrospinning, and cut into short fibers by high speed dispersion. CPC with calcium phosphorus ratio of 1.5:1 was prepared by Biocement D method. The composition and structure of CPC, CSNF, RGD modified CSNF (CSNF-RGD), CSNF enhanced CPC (CPC-CSNF), RGD modified CPC-CSNF (CPC-CSNF-RGD) were observed by infrared spectrum, X-ray diffraction (XRD) and scan electron microscopy (SEM). The mechanical properties were measured by universal mechanical testing instrument. The adhesion and proliferation of MC3T3 cells were assessed using immunofluorescence staining and MTT method. Results: The distribution of CSNF in the scaffold was homogeneous, and the porous structure between the nanofibers was observed by SEM. The infrared spectrum showed the characteristic peaks at 1633 nm and 1585 nm, indicating that RGD was successfully grafted on chitosan nanofibers. The XRD pattern showed that the bone cement had a certain curability. The stain-stress test showed that break strengths were (17.74±0.54) MPa for CPC-CSNF and (16.67±0.56) MPa for CPCP-CSNF-RGD, both were higher than that of CPC(all P<0.05). The immunofluorescence staining and MTT results indicated that MC3T3 cells grew better on CPC-CSNF-RGD after 240 min of culture(all P<0.05). Conclusion: CSNF-RGD can improve the biomechanical property and biocompatibility of CPC, indicating its potential application in bone tissue repair.
3T3 Cells ; Animals ; Biocompatible Materials ; Bone Cements ; chemistry ; metabolism ; pharmacology ; Calcium Phosphates ; metabolism ; Cell Proliferation ; drug effects ; Chitosan ; chemistry ; pharmacology ; Mice ; Nanofibers ; chemistry ; Oligopeptides ; chemistry

The RGD-containing peptide was used to modify the surface of porous PLGA-[ASP-PEG], and was incubated in the modified simulated body fluid (mSBF) for two weeks. The mineralization of PLGA-[ASP-PEG] was explored. The active peptide was used to modify PLGA-[ASP-PEG] through cross-linker (Sulfo-LC-SPDP), characterized by X-ray photoelectron spectroscopy (XPS) the peptide-modified PLGA-[ASP-PEG] (Experiment group, EG) and PLGA-[ASP-PEG] without modification (Control group, CG) were all incubated in mSBF for two weeks, confirmed by observation of Scanning electron microscope(SEM) and measurements of Energy dispersive analysis system of X-ray (EDS) and X-ray diffractometry (XRD). XPS indicated that the binding energy of sulphur in EG was 164eV, and the ratio of carbon to sulphur in EG was 99.746 : 0.1014, however, sulphur was not detected in CG; SEM analysis demonstrated that the mineralization layers were more consecutive and compact in EG than in CG. The results of EDS and XRD indicated that the main component of mineral was hydroxyapatite, and the ratio of Ca/P was 1.60 in EG, and 1.52 in CG. RGD-containing peptide provided enough functional groups for mineralization; the mineralized peptide- modified PLGA-[ASP-PEG] possessed the bonelike microstructure.
Biocompatible Materials ; chemistry ; Bone Substitutes ; Bone and Bones ; metabolism ; Calcification, Physiologic ; Lactic Acid ; chemistry ; Oligopeptides ; chemistry ; Osteogenesis ; drug effects ; Peptides ; chemical synthesis ; pharmacology ; Polyglycolic Acid ; chemistry ; Surface Properties

The purpose of the study is to construct R8 peptide (RRRRRRRR) and pH sensitive polyethylene glycols (PEG) co-modified liposomes (Cl-Lip) and utilize them in breast cancer treatment. The co-modified liposomes were prepared with soybean phospholipid, cholesterol, DSPE-PEG2K-R8 and PEG5K-Hz-PE (pH sensitive PEG). The size and zeta potential of Cl-Lip were also characterized. The in vitro experiment demonstrated that the Cl-Lip had high serum stability in 50% fetal bovine serum. The cellular uptake of Cl-Lip under different pre-incubated conditions was evaluated on 4T1 cells. And the endocytosis pathway, lysosome escape ability and tumor spheroid penetration ability were also evaluated. The results showed the particle size of the Cl-Lip was (110.4 ± 5.2) nm, PDI of the Cl-Lip was 0.207 ± 0.039 and zeta potential of the Cl-Lip was (-3.46 ± 0.05) mV. The cellular uptake of Cl-Lip on 4T1 cells was pH sensitive, as the cellular uptake of Cl-Lip pre-incubated in pH 6.0 was higher than that of pH 7.4 under each time point. The main endocytosis pathways of Cl-Lip under pH 6.0 were micropinocytosis and energy-dependent pathway. At the same time, the Cl-Lip with pre-incubation in pH 6.0 had high lysosome escape ability and high tumor spheroid penetration ability. All the above results demonstrated that the Cl-Lip we constructed had high pH sensitivity and is a promising drug delivery system.
Animals ; Cell Line, Tumor ; Cell-Penetrating Peptides ; chemical synthesis ; chemistry ; Cholesterol ; chemistry ; Drug Delivery Systems ; Liposomes ; Mice ; Oligopeptides ; chemical synthesis ; chemistry ; Particle Size ; Phospholipids ; chemistry ; Polyethylene Glycols

Ubiquitin-proteasome pathway (UPP) is one of the ways utilized for selective degradation of many proteins in cells, and the 20S proteasome takes the functional machinery where hydrolysis of targeted proteins takes place. Based on existing peptide inhibitors, a series of novel tripeptidic tetrazoles have been designed, synthesized, and the structures have been confirmed with 1H NMR, MS and elemental analysis. Among them, three compounds (6b, 6d and 6h) showed inhibitory activities of ChT-L of 20S proteasome.
Biological Assay ; Drug Design ; Molecular Structure ; Oligopeptides ; chemical synthesis ; chemistry ; pharmacology ; Proteasome Endopeptidase Complex ; chemistry ; Proteasome Inhibitors ; chemical synthesis ; chemistry ; pharmacology ; Tetrazoles ; chemical synthesis ; chemistry ; pharmacology

Arg-Gly-Asp-(RGD) containing peptide characterized as the non-viral gene vector was synthesized to modify the surface of PLGA-(ASP-PEG). The Peptide (K16-GRGDSPC) was synthesized. PLGA-(ASP-PEG) was executed into chips A, B and C. Chip C was regarded as control. Chips A and B reacted with the cross-linker, then Chip A reacted with peptide. Mass spectrometry (MS) and high performance liquid chromatography (HPLC) detected the molecular weight and the purity of peptide. Sulphur in the surface of materials was detected by X-ray photoelectron spectrometry (XPS). The peptide content in the residual solution was detected by Spectrometer. HPLC showed the peptide purity was 94.13%; MS showed the molecular weight was 2741.26. XPS revealed the binding energy of the sulphur in reacted Chip A was 164 eV in reacted Chip B, 164eV and 162 eV; the ratios of carbon to sulphur in reacted Chip A and B were 99.746:0.1014 and 99.574:0.4255, respectively. There was no sulphur in Chip C. The optical density value (OD) of the resident solution was 0.069. The peptide density of reacted Chip A was 0.04 mg/mm2. The peptide was manufactured and linked to the surface of the biomimetic PLGA-(ASP-PEG) with the cross-linker.
Aspartic Acid ; chemistry ; Biocompatible Materials ; chemistry ; Cross-Linking Reagents ; chemistry ; Genetic Vectors ; chemical synthesis ; chemistry ; Humans ; Lactic Acid ; chemistry ; Oligopeptides ; chemistry ; Polyethylene Glycols ; chemistry ; Polyglycolic Acid ; chemistry ; Surface Properties ; Tissue Engineering