scholarly journals The Degradation Properties of MgO Whiskers/PLLA Composite In Vitro

2018 ◽  
Vol 19 (9) ◽  
pp. 2740 ◽  
Author(s):  
Yun Zhao ◽  
Bei Liu ◽  
Hongwei Bi ◽  
Jinjun Yang ◽  
Wei Li ◽  
...  
Keyword(s):  
Ph Value ◽  
Composite Films ◽  
Phosphate Buffer Solution ◽  
Buffer Solution ◽  
In Vitro Degradation ◽  
Final Weight ◽  
Cell Affinity ◽  
Degradation Properties ◽  
Composite Samples

In this study, composite films of stearic acid–modified magnesium oxide whiskers (Sa–w-MgO)/poly-l-lactic acid (PLLA) were prepared through solution casting, and the in vitro degradation properties and cytocompatibility of the composites with different whisker contents were investigated. The results showed that the degradation behavior of the composite samples depended significantly on the whisker content, and the degradation rate increased with the addition of MgO content. Furthermore, the degradation of the composites with higher contents of whiskers was influenced more severely by the hydrophilicity and pH value, leading to more final weight loss, but the decomposition rate decreased gradually. Furthermore, the pH value of the phosphate buffer solution (PBS) was obviously regulated by the dissolution of MgO whiskers through neutralization of the acidic product of PLLA degradation. The cytocompatibility of the composites also increased remarkably, as determined from the cell viability results, and was higher than that of PLLA at the chosen whisker content. This was beneficial for the cell affinity of the material, as it notably led to an enhanced biocompatibility of the PLLA, in favor of promoting cell proliferation, which significantly improved its bioactivity, as well.

scholarly journals Effects of Magnesium Oxide (MgO) Shapes on In Vitro and In Vivo Degradation Behaviors of PLA/MgO Composites in Long Term

Polymers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1074 ◽  
Author(s):  
Yun Zhao ◽  
Hui Liang ◽  
Shiqiang Zhang ◽  
Shengwei Qu ◽  
Yue Jiang ◽  
...  
Keyword(s):  
Magnesium Oxide ◽  
Ph Value ◽  
Phosphate Buffer Solution ◽  
Buffer Solution ◽  
Biomedical Material ◽  
Degradation Behaviors ◽  
In Vivo Degradation

Biodegradable devices for medical applications should be with an appropriate degradation rate for satisfying the various requirements of bone healing. In this study, composite materials of polylactic acid (PLA)/stearic acid-modified magnesium oxide (MgO) with a 1 wt% were prepared through blending extrusion, and the effects of the MgO shapes on the composites’ properties in in vitro and in vivo degradation were investigated. The results showed that the long-term degradation behaviors of the composite samples depended significantly on the filler shape. The degradation of the composites is accelerated by the increase in the water uptake rate of the PLA matrix and the composite containing the MgO nanoparticles was influenced more severely by the enhanced hydrophilicity. Furthermore, the pH value of the phosphate buffer solution (PBS) was obviously regulated by the dissolution of MgO through the neutralization of the acidic product of the PLA degradation. In addition, the improvement of the in vivo degrading process of the composite illustrated that the PLA/MgO materials can effectively regulate the degradation of the PLA matrix as well as raise its bioactivity, indicating the composites for utilization as a biomedical material matching the different requirements for bone-related repair.

scholarly journals In Vitro Structural Changes of Nano-Bacterial Cellulose Immersed in Phosphate Buffer Solution

2011 ◽  
Vol 10 ◽  
pp. 55-66 ◽  
Author(s):  
Yan Mei Chen ◽  
Ting Fei Xi ◽  
Yu Feng Zheng ◽  
Liang Zhou ◽  
Yi Zao Wan
Keyword(s):  
Bacterial Cellulose ◽  
Phosphate Buffer ◽  
Structural Changes ◽  
Ph Value ◽  
Phosphate Buffer Solution ◽  
Buffer Solution ◽  
Potential Applications ◽  
Scaffold Materials

Nano-bacterial cellulose (nBC), secreted by Acetobacter xylinum, is expected to have potential applications in tissue engineering. In this paper, the in-vitro degradation performance and the corresponding mechanism of nBC immersed in phosphate buffer solution (PBS) for different time periods was investigated. The pH value variation of solution, material degradation, and the swelling and structural changes of nBC was analysed successively. The results indicate that water molecules attack the exposed nBC fibrils, weakening the bonding strength of inter- and intra-molecular chains and disconnecting partial C-O-C bonds. The disconnection of C-O-C bonds is considered the primary reason for the degradation of nBC large molecular chains after nBC is immersed in PBS. The present work is instructive for controlling the in-vivo degradation performance of nBC acting as bone tissue engineered scaffold materials.

Improving Topical Skin Delivery of Monocrotaline Via Liposome Gel-based Nanosystems

2019 ◽  
Vol 16 (10) ◽  
pp. 940-950 ◽  
Author(s):  
Jiandong Yu ◽  
Zhi Chen ◽  
Yan-zhi Yin ◽  
Chaoyuan Tang ◽  
Enying Hu ◽  
...  
Keyword(s):  
Gradient Method ◽  
Encapsulation Efficiency ◽  
Ph Value ◽  
Topical Administration ◽  
Ph Gradient ◽  
Stability Factor ◽  
Buffer Solution ◽  
Skin Delivery ◽  
Skin Retention

Background: In this study, a liposomal gel based on a pH-gradient method was used to increase the skin-layer retention of monocrotaline (MCT) for topical administration. Methods: Using the Box-Behnken design, different formulations were designed to form liposome suspensions with optimal encapsulation efficiency (EE%) and stability factor (KE). In order to keep MCT in liposomes and accumulate in skin slowly and selectively, MCT liposome suspensions were engineered into gels. Results: A pH-gradient method was used to prepare liposome suspensions. The optimal formulation of liposome suspensions (encapsulation efficiency: 83.10 ± 0.21%) was as follows: MCT 12 mg, soybean phosphatidyl choline (sbPC) 200 mg, cholesterol (CH) 41 mg, vitamin E (VE) 5 mg, and citric acid buffer solution (CBS) 4.0 10 mL (pH 7.0). The final formulation of liposomal gels consisted of 32 mL liposome suspensions, 4.76 mL deionized water, 0.40 g Carbopol-940, 1.6 g glycerol, 0.04 g methylparaben, and a suitable amount of triethanolamine for pH value adjustment. The results of in vitro drug release showed that MCT in liposomal gels could be released in 12 h constantly in physiological saline as a Ritger-Peppas model. Compared with plain MCT in gel form, liposomal MCT in gel had higher skin retention in vitro. Conclusion: In this study, liposomal gels were formed for greater skin retention of MCT. It is potentially beneficial for reducing toxicities of MCT by topical administration with liposomal gel.

Bacterial chemotaxis to fungal propagules in vitro and in soil

1983 ◽  
Vol 29 (9) ◽  
pp. 1104-1109 ◽  
Author(s):  
D. K. Arora ◽  
A. B. Filonow ◽  
J. L. Lockwood
Keyword(s):  
Sandy Loam ◽  
Phosphate Buffer Solution ◽  
Bacterial Chemotaxis ◽  
Macrophomina Phaseolina ◽  
Buffer Solution ◽  
Erwinia Herbicola ◽  
Cochliobolus Victoriae ◽  
Fungal Propagules ◽  
Loam Soil

Erwinia herbicola, Pseudomonas fluorescens, and P. putida were strongly attracted in vitro to substances exuded by conidia of Cochliobolus victoriae and sclerotia of Macrophomina phaseolina, but not to phosphate buffer solution. Numbers of bacteria attracted to propagules of C. victoriae or M. phaseolina in an unsterilized sandy loam soil were significantly (P = 0.05) greater than background populations occurring in soil saturated with buffer. Chemotactic response was greater to C. victoriae than to M. phaseolina both in vitro and in soil. Results suggest that living fungal propagules may act as attractants for motile bacteria in soil.

Surface Morphological Changes Accompanying Dissolution of Bioactive Glass: Effect of Residual Stress

2008 ◽  
Vol 47-50 ◽  
pp. 1302-1306 ◽  
Author(s):  
John A. Nychka ◽  
Ding Li
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Bioactive Glass ◽  
Morphological Changes ◽  
Phosphate Buffer Solution ◽  
Buffer Solution ◽  
Mechanochemical Effect ◽  
Dissolution Behaviour ◽  
Glass Surfaces

We report our observations concerning the time evolution of surface morphology occurring during the in vitro immersion of bioactive glass surfaces in contact with phosphate buffer solution. We compare regions under intentionally produced residual stresses via micro-indentation to those where no indentation was performed. The sign of the residual stress is shown to be important for predicting dissolution behaviour; compression retards dissolution, whereas tension enhances dissolution. We analyze our results with a simple model for the work of bond dissociation. We report that a highly constrained residual compressive stress state, such as in an indent, leads to a work deficit in comparison to tension, which accounts for the slower dissolution rate of compressed bioactive glass. Such a mechanochemical effect suggests that the presence of residual stresses from the manufacture of biomedical implants and devices could lead to accelerated or delayed dissolution and that careful control of residual stresses should be sought for predictable performance in dissolvable materials.

The Study of Albumin Release from Silica/Albumin as a Potential Drug Delivery Carrier

2014 ◽  
Vol 69 (5) ◽  
Author(s):  
Shafiyah Pondi ◽  
Jon Efendi ◽  
Ho Chin Siong ◽  
Lai Sin Yuan ◽  
Sheela Chandren ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Fumed Silica ◽  
In Vitro Release ◽  
Phosphate Buffer Solution ◽  
Buffer Solution ◽  
Solution Ph ◽  
Drug Delivery Carrier ◽  
High Interaction ◽  
Uv Visible

The drug-delivery field has been an attractive as well as challenging area for research. With the emerging of new formulated drugs and pharmaceutical compounds, development of good drug-delivery system (DDS) is crucially required. This study aims to utilize albumin as the drug template in silica/albumin/drug (S/A/D) system. Prior to designing this system, the interaction between silica and albumin was investigated. It is hypothesized that high interaction between silica and albumin may result in slower drug release over time, which is preferred for a good DDS. Silica and albumin (S/A) materials were prepared by using fumed silica and tetraethyl orthosilicate (TEOS) as the silica precursors. Three different S/A samples were prepared; fumed silica with albumin (FS/A), fumed silica with pre-treated albumin by sodium borohydrate (FS/A-N), and silica sol (TEOS) with albumin (SS/A). In-vitro release of albumin in phosphate buffer solution (pH 7) was carried out to examine the interaction between albumin and silica. The concentration of albumin was detected at 280 nm by UV-visible spectrophotometer. All samples were characterized by diffuse reflectance-UV-visible spectrophotometer (DR-UV), Fourier transform infrared spectrophotometer (FTIR) dan thermogravimetric-differential thermal analysis (TG-DTA). DR-UV results show that SS/A exhibited the lowest absorption intensity at 280 nm, which indicates better interaction between silica and albumin. This result was supported by the presence of Si-O stretching band of silanol at 952 cm-1 from the FTIR spectrum. Release study of albumin demonstrated that the release of albumin from SS/A was slowest compared to those of FS/A and FS/A-N. 

Drug-loaded ultrafine poly(vinyl alcohol) fibre mats prepared by electrospinning

e-Polymers ◽  
2005 ◽  
Vol 5 (1) ◽  
Author(s):  
Chunxue Zhang ◽  
Xiaoyan Yuan ◽  
Lili Wu ◽  
Jing Sheng
Keyword(s):  
Drug Release ◽  
Photoelectron Spectroscopy ◽  
Vinyl Alcohol ◽  
Phosphate Buffer Solution ◽  
Poly Vinyl Alcohol ◽  
High Porosity ◽  
Buffer Solution ◽  
Drug Molecules ◽  
Alcohol Fibre

AbstractSubmicron poly(vinyl alcohol) (PVA) fibre mats embedded with Aspirin and bovine serum albumin (BSA) were prepared by electrospinning of their aqueous solutions. Fibre morphology was investigated by scanning electron microscopy. The composition of the fibre mats was characterized by Fourier transform IR spectroscopy and X-ray photoelectron spectroscopy. The in vitro drug release was investigated by immersing the fibre mats in phosphate buffer solution at 37°C. Results indicated that the morphology of fibre mats was influenced by the amount of drug, and more beaded and irregularly shaped fibres were found with increasing drug amounts. There were drug molecules distributed on the surface of the PVA fibres. Studies of in vitro drug release showed that both Aspirin and BSA were released more quickly from PVA fibre mats than from PVA films because of the large surface area and high porosity of the fibre mats.

scholarly journals Drug Leaching Properties of Vancomycin Loaded Mesoporous Hydroxyapatite as Bone Substitutes

Processes ◽  
2019 ◽  
Vol 7 (11) ◽  
pp. 826 ◽  
Author(s):  
Jayasingh Anita Lett ◽  
Suresh Sagadevan ◽  
Joseph Joyce Prabhakar ◽  
Nor Aliya Hamizi ◽  
Irfan Anjum Badruddin ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Pore Size ◽  
In Vitro Release ◽  
Phosphate Buffer Solution ◽  
Bone Substitutes ◽  
Organic Modifiers ◽  
Buffer Solution ◽  
Modern Health Care ◽  
Impregnation Technique

Infections after bone reconstructive surgery become an authentic therapeutic and economic issue when it comes to a modern health care system. In general; infected bone defects are regarded as contraindications for bone grafting. Since the pathogens develop a biofilm on the inner surface of the bone; local delivery of antibiotics becomes more important. The present work focuses on the synthesis of Mesoporous Hydroxyapatite (MPHAP) loaded with drug Vancomycin (Van) and to investigate its loading and leaching ability in phosphate buffer solution (PBS), to be used for post-operative infections. The effect of pore size on MPHAP was analyzed using different fatty acids as organic modifiers. The impacts of various fatty acids chain length on the morphology and pore size were studied. A simple impregnation technique with optimized conditions ensured a high antibiotic loading (up to 0.476 + 0.0135 mg/mL), with a complete in vitro release obtained within 50 h.

A Comparative Study of the Corrosion Resistance of Stainless Steels Obtained by Powder Metallurgy Techniques for Application in Dental Prosthesis

2010 ◽  
Vol 660-661 ◽  
pp. 617-622 ◽  
Author(s):  
Rogério Albuquerque Marques ◽  
Adonis M. Saliba-Silva ◽  
Sizue Ota Rogero ◽  
Maria de Fátima Montemor ◽  
Isolda Costa
Keyword(s):  
Corrosion Resistance ◽  
Powder Metallurgy ◽  
Stainless Steels ◽  
Electrochemical Techniques ◽  
Phosphate Buffer Solution ◽  
Dental Prosthesis ◽  
Powder Injection ◽  
Potential Candidate ◽  
Buffer Solution

- Ferromagnetic stainless steels (SS) produced by powder metallurgy (PM) techniques have been investigated as potential candidates for dental prosthesis applications in replacement of magnetic attachments made of noble and expensive alloys. Two SS were investigated: SS 17-4 PH produced by powder injection (PIM) and SS PM2000 obtained by mechanical alloying. In vitro cytotoxicity analysis of the two SS showed no cytotoxic effects. The magnetic retention force of both tested SS was also evaluated and they were comparable to noble commercially available material that is in use at the moment. The corrosion resistance of both SS was evaluated by electrochemical techniques in sodium phosphate buffer solution (PBS) at 37°C. The AISI 316L SS was also tested under the same conditions for comparison reasons. SS samples tested showed passive behaviour in the electrolyte, but they also presented susceptibility to pitting. The best pitting resistance was associated to the PM2000 whereas the 17-4PH PIM showed the highest pitting susceptibility among the tested steels. The results pointed out that the PM2000 SS might be considered a potential candidate for substitution of high cost magnetic alloys used in dental prosthesis.

Preparation and Degradation Properties of Hydroxyethyl Chitosan-g-Poly(D,L-Lactide) Copolymers

2012 ◽  
Vol 457-458 ◽  
pp. 308-313
Author(s):  
Bing Hong Luo ◽  
Jian Hua Li ◽  
Wan Xu ◽  
Chang Ren Zhou
Keyword(s):  
Ring Opening ◽  
Ph Value ◽  
Saline Water ◽  
Feed Ratio ◽  
Casting Method ◽  
Composition And Structure ◽  
Solution Casting Method ◽  
Lactide Copolymers ◽  
Degradation Properties

The goal of the present study was to investigate the degradation of hydroxyethyl chitosan-g-poly(D,L-lactide) (HECS-g-PDLLA) copolymers in vitro. For this purpose, HECS-g-PDLLA copolymers were firstly synthesized by bulk ring-opening polymerization with different nD,L-lactide:naminoglucoside feed ratio. Then, a series of poly(D,L-lactide), chitosan and HECS-g-PDLLA copolymers films were prepared by solution casting method, and their degradation were carried out in vitro in saline water at 37 °C. The degradation properties were investigated by measurement of pH value, weight loss, and changes in the composition and structure of the HECS-g-PDLLA copolymers films with time. Results showed that the degradation of the HECS-g-PDLLA copolymers occurred firstly on the poly(D,L-lactide) side chains. The degradation rate of the graft copolymers obviously faster than that of CS, and can be controlled by changing the value of nD,L-lactide:naminoglucoside. Due to the alkalinity of CS, the pH value of saline water for HECS-g-PDLLA copolymers degradation higher than that of PDLLA.

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