Can nanoparticles and nano‒protein interactions bring a bright future for insulin delivery?

Insulin therapy plays an essential role in the treatment of diabetes mellitus. However, frequent injections required to effectively control the glycemic levels lead to substantial inconvenience and low patient compliance. In order to improve insulin delivery, many efforts have been made, such as developing the nanoparticles (NPs)-based release systems and oral insulin. Although some improvements have been achieved, the ultimate results are still unsatisfying and none of insulin-loaded NPs systems have been approved for clinical use so far. Recently, nano‒protein interactions and protein corona formation have drawn much attention due to their negative influence on the

Effect of three kinds of medium molecular weight proteins on the corrosion resistance of Ni-Ti and stainless steel arch wires / 口腔疾病防治

Objective @#To explore the influence and mechanism of different types of proteins on the corrosion resistance of alloy to provide a reference for the safe application and surface modification of nickel-titanium (Ni-Ti) and stainless steel bow wires in the clinic.@*Methods@#The effects of fibrinogen, IgG and mucin on the electrochemical corrosion resistance of Ni-Ti and stainless steel arch wires were tested by the potentiodynamic polarization method, and the repair ability of passive films on surfaces treated with the three proteins were tested by the cyclic polarization method. Inductively coupled plasma optical emission spectrometry (ICP-OES) was used to determine the types of corrosion products, and the surface morphology after corrosion was analyzed by scanning electron microscopy (SEM) and atomic force microscopy (AFM).@*Results @#The addition of fibrinogen, IgG or mucin to an alloy has different effects on its corrosion resistance. Adding protein can reduce the corrosion resistance of stainless steel alloys and slow the corrosion process of Ni-Ti alloys. The addition of mucin can improve the corrosion resistance of Ni-Ti alloy and the repair ability of passive film. Compared with mucin and IgG, fibrinogen can reduce the pitting resistance of Ni-Ti and stainless steel alloys.@*Conclusion @#Different types of proteins interact differently with the arch wire, form different deposition morphologies on the surface, and participate differently in the corrosion process of the alloy.

Evolution of lubricating adsorption films with protein aqueous solution under impact loads / 医用生物力学

Objective To study the dynamic growth of adsorption films on solid surfaces in point contacts with aqueous protein aqueous solutions and investigate the dominating factors. Methods The formation of the adsorption films within a ball-on-disc contact was measured using optical interference technique. The effects of impact loads, impact times and surface properties of the materials on the adsorption of BSA aqueous solution were also studied. Results Under dynamic conditions, the thickness of the adsorption film was much higher than that under static condition. The adsorption film was growing with increasing impact times and finally the stable thickness could be achieved. Small loads and hydrophobic materials were favorable for the growth of the adsorption film. The BSA adsorption film was easy to grow on the steel surface, but on the ceramic surface the adsorption film thickness was low. Conclusions The research about adsorbed lubricating films evolution of protein aqueous solution under impact loads is of clinical significance for treating and preventing of artificial prosthesis.

Evolution of lubricating adsorption films with protein aqueous solution under impact loads / 医用生物力学

Objective To study the dynamic growth of adsorption films on solid surfaces in point contacts with aqueous protein aqueous solutions and investigate the dominating factors.Methods The formation of the adsorption films within a ball-on-disc contact was measured using optical interference technique.The effects of impact loads,impact times and surface properties of the materials on the adsorption of BSA aqueous solution were also studied.Results Under dynamic conditions,the thickness of the adsorption film was much higher than that under static condition.The adsorption film was growing with increasing impact times and finally the stable thickness could be achieved.Small loads and hydrophobic materials were favorable for the growth of the adsorption film.The BSA adsorption film was easy to grow on the steel surface,but on the ceramic surface the adsorption film thickness was low.Conclusions The research about adsorbed lubricating films evolution of protein aqueous solution under impact loads is of clinical significance for treating and preventing of artificial prosthesis.

Preparation and properties of polydopamine coating on the surface of C/C composites / 军事医学

Objective Carbon/carbon ( C/C) composites are a potential material for bone repair .To improve the hydrophilicity and biological activity of C/C composites , polydopamine coating was prepared on the surface of C /C composites.Methods By changing the coating time and coating environment ( oxygen or air atmosphere ), a series of polydopamine coating samples were prepared . The water contact angle test , scanning electron microscope , energy dispersive spectrometer , atomic force microscope and protein adsorption test were used to characterize the properties of different samples.Then, the data were analyzed to optimize preparation conditions .Results When the concentration of dopamine was 2.0 g/L,and the coating time was 30 min (oxygen atmosphere) +11.5 h (air atmosphere), the water contact angle was decreased from 64.0°(blank sample) to 25.9°, suggesting that the hydrophilicity was improved greatly . The results of the scanning electron microscope , energy dispersive spectrometer and atomic force microscope showed that the coating was uniform and dense .The amount of protein adsorption per sample was 0.2817 mg.Conclusion The polydopamine coating on the C/C composites improves its hydrophilicity and biological activity , which indicates that the polydopamine coated C/C composites will be a new potential material for bone tissue repair .

The effect of urea on the corrosion behavior of different dental alloys.

Objective: Intraoral corrosion of dental alloys has biological, functional, and esthetic consequences. Since it is well known that the salivary urea concentrations undergo changes with various diseases, the present study was undertaken to determine the effect of salivary urea concentrations on the corrosion behavior of commonly used dental casting alloys. Materials and Methods: Three casting alloys were subjected to polarization scans in synthetic saliva with three different urea concentrations. Results: Cyclic polarization clearly showed that urea levels above 20 mg/100 ml decreased corrosion current densities, increased the corrosion potentials and, at much higher urea levels, the breakdown potentials. Conclusion: The data indicate that elevated urea levels reduced the corrosion susceptibility of all alloys, possibly through adsorption of organics onto the metal surface. This study indicates that corrosion testing performed in sterile saline or synthetic saliva without organic components could be misleading.

Investigation on the mechanisms for biocompatibility of chitosan using agarose/chitosan blended hydrogels as a model / 国际生物医学工程杂志

ObjectiveTo investigate the possible mechanisms for biocompatibility of chitosan material using agarose/chitosan blended hydrogels as a model.Methods A series of agarose/chitosan blended hydrogels with different chitosan content were prepared by the blending method.The chemical groups of the blended hydrogels were analyzed by the Fourier transform infrared (FTIR) spectroscopy.The blending compatibility between the agarose and chitosan was evaluated with the fluorescein-4-isothiocyanate (FITC) staining method.The charge of the blended hydrogels was determined by the zeta potential measurement.The adsorption of total fetal bovine serum (FBS) proteins and bovine serum albumin (BSA) on the blended hydrogels was measured by the bicinchoninic acid (BCA) method.The adsorption of fibronectin (FN) on the blended hydrogels was measured with ELISA.Cell culture experiment adopted human microvascular endothelial cell line (HMEC-1) as the model.The cytocompatibility was studied by evaluating adhesion,proliferation,and morphology of the cells on the blended hydrogels.Results Characteristic chemical groups of chitosan could be detected in the agarose/chitosan blended hydrogels.The chitosan had a good blending compatibility with the agarose.The amino groups of chitosan were uniformly distributed in the blended hydrogels.The blended hydrogels were strongly positively charged at acidic pH (pH 3.0),however,the zeta potentials of all the hydrogels were reduced to nearly 0 mV at neutral pH (pH 7.4).There were no significant differences in the adsorption of total FBS proteins and BSA between the blended hydrogel groups.However,the adsorption of FN on the hydrogels significantly increased with the increase of chitosan content.Cell culture experiment indicated that the cytocompatibihty of the blended hydrogels was significantly improved with the increase of chitosan content.The HMECs exhibited higher levels of adhesion,spreading,and proliferation on the hydrogels with higher chitosan content.ConclusionResults in this study indicated that the chitosan component preferentially adsorbed FN compared to the other serum proteins,leading to adhesion and spreading of the cells on the blended hydrogels.In contrast to prevailing views,it was found in the present study that the biocompatibility of chitosan did not relate to its positive charge.

A study of ion-exchange chromatography in an expanded bed for bovine albumin recovery

In the present work, the effect of bed expansion on BSA adsorption on Amberlite IRA 410 ion-exchange resin was studied. The hydrodynamic behavior of an expanded bed adsorption column on effects of the biomolecules and salt addition and temperature were studied to optimize the conditions for BSA recovery on ion-exchange resin. Residence time distribution showed that HEPT, axial dispersion and the Pecletl number increased with temperature and bed height, bed voidage and linear velocity. The binding capacity of the resin increased with bed height. The Amberlite IRA 410 ion-exchange showed an affinity for BSA with a recovery yield of 78.36 percent of total protein.

No presente trabalho foi estudado o efeito da expansão do leito sobre a adsorção de BSA na resina de troca iônica Amberlite IRA 410. O comportamento hidrodinâmico de uma coluna de adsorção em leito expandido sob efeito da adição de biomoléculas, sal e variação da temperatura também foi estudado para obter as condições ótimas de recuperação da BSA sob a resina de troca iônica. A distribuição do tempo de residência mostrou que a HEPT, a dispersão axial e o número de Pecletl aumentaram com a temperatura, altura do leito, porosidade do leito e velocidade linear. A capacidade de ligação da resina aumentou com a expansão do leito. A resina de troca iônica Amberlite IRA 410 mostrou ter afinidade pela BSA, com uma recuperação de 78,36 por cento da proteína total.