Preparation and Testing of Polylactic Acid Ultra Thin Fiber Membrane as the Sustained Release Material

2012 ◽  
Vol 538-541 ◽  
pp. 68-71 ◽  
Author(s):  
Jian Xiang Yu ◽  
Tai Qi Liu
Keyword(s):  
Molecular Weight ◽  
Sustained Release ◽  
Polylactic Acid ◽  
Fiber Diameter ◽  
Phosphate Buffer Solution ◽  
Diameter Distribution ◽  
Fiber Membrane ◽  
Buffer Solution ◽  
Thin Fiber ◽  
Better Than

In his paper, polylactic acid ultra- thin fibers membrane carried rifampicin were prepared by electrospinning technology, and release experiment of polylactic acid super thin fiber membrane with rifampicin were carried out in PBS solution. The resulted ultra-fine fibers membrane of polylactic acid membrane were characterized through scanning electron microscopy to decided the morphology, the results showed that the drug-loaded polylactic acid membrane contained microfiber in a range of 1μm-8μm in diameter; polylactic acid fiber diameter distribution was affected by molecular weight of polylactic acid, concentration of polylactic acid, quantity of drug loaded and spinning parameters such as voltage, the average fiber diameter increased when improved the mass fraction of PLA solution, the diameter of PLA ultra-fine fibers loaded rifampicin was thiner than PLA ultra-fine fibers. The performance of controlled release in phosphate buffer solution (PBS) was detected by UV, and their delivery rate was calculated by the detected result. The sustained release effect of polylactic acid Molecular with weight of 150,000 loaded rifampicin was better than polylactic acid ultra-fine fibers with the molecular weight of 100,000, the addition of lipase can improve release rate of rifampicin.

scholarly journals Biological Compatibility of a Polylactic Acid Composite Reinforced with Natural Chitosan Obtained from Shrimp Waste

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1465 ◽  
Author(s):  
Yaret Torres-Hernández ◽  
Gloria Ortega-Díaz ◽  
Lucía Téllez-Jurado ◽  
Nayeli Castrejón-Jiménez ◽  
Alejandro Altamirano-Torres ◽  
...  
Keyword(s):  
Cell Viability ◽  
Polylactic Acid ◽  
Low Cost ◽  
Hydrolytic Degradation ◽  
Phosphate Buffer Solution ◽  
Morphological Characteristics ◽  
Buffer Solution ◽  
Composite Surface ◽  
Biological Compatibility

The aim of this work is to evaluate the effect of chitosan content (1, 3 and 5 wt %) dispersed in polylactic acid (PLA) on the structure and properties of composites. Also, the hydrolytic degradation, and the cell viability and adhesion of human MG-63 osteoblasts are analyzed to determine the composites’ suitability for use in tissue engineering. For the manufacture of the materials, natural chitosan was extracted chemically from shrimp exoskeleton. The composites were fabricated by extrusion, because it is a low-cost process, it is reproducible, and it does not compromise the biocompatibility of the materials. FT-IR and XRD show that the chitosan does not change the polymer structure, and interactions between the composite components are discarded. In vitro degradation tests show that the composites do not induce significant pH changes in phosphate buffer solution due to their low susceptibility to hydrolytic degradation. The adhesion and morphological characteristics of the osteoblasts are evaluated using confocal microscopy and scanning electron microscopy. The cell viability is determined by the MTT assay. Osteoblasts adhesion is observed on the surface of PLA and composites. A higher amount of chitosan, higher number of cells with osteoblastic morphology, and mineralized nodules are observed on the composite surface. The highest metabolic activity is evidenced at 21 days. The results suggest that the Polylactic acid/chitosan composites are potentially suitable for use as a biomaterial.

The Melt Electrospinning of Polycaprolactone (PCL) Ultrafine Fibers

2008 ◽  
Vol 1134 ◽  
Author(s):  
Chitrabala Subramanian ◽  
Samuel C. Ugbolue ◽  
Steven B. Warner ◽  
Prabir K. Patra
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
Process Parameters ◽  
Applied Voltage ◽  
Fiber Diameter ◽  
Diameter Distribution ◽  
Electrospun Fibers ◽  
Ultrafine Fibers ◽  
Melt Electrospinning ◽  
Fiber Diameter Distribution

AbstractElectrospinning is a technique of producing nanofibers from polymer solution/melt solely under the influence of electrostatic forces. In this research, we investigated the formation of nanofibers by melt electrospinning polycaprolactone (PCL). The effect of process parameters such as molecular weight, applied voltage, and electrode separation on the fiber diameter was investigated. Controlling the process parameters could help increase the proportion of ultrafine fibers in the melt electrospun nonwoven mat. The velocity of the straight jets was in the range of 0.2-1 m/s. The melt electrospun fibers were characterized with respect to fiber diameter, distribution, mechanical properties and birefringence. Melt electrospun polycaprolactone fibers had a diameter distribution of the order of 5 -20 μm. The birefringence of the melt electrospun fibers increased with decrease in fiber diameter.

scholarly journals Meltblown Fabrics from Biodegradable Polymers

2001 ◽  
Vol os-10 (1) ◽  
pp. 1558925001os-10 ◽  
Author(s):  
Dieter H. Müller ◽  
Andreas Krobjilowski
Keyword(s):  
Molecular Weight ◽  
Biodegradable Polymers ◽  
Fiber Diameter ◽  
Thermoplastic Starch ◽  
Diameter Distribution ◽  
Processing Conditions ◽  
Narrow Molecular Weight Distribution ◽  
Melt Flow Rate ◽  
Fine Fiber ◽  
Polymer Distribution

This paper describes the processing of biodegradable polymers in the meltblowing process. The processing of such materials is still in the development stages as their rheological behavior gives a strong restriction for such applications. Meltblowing experiments were carried out with different polymers, including polylactide, polyesteramide, polyvinylalcohol, cellulosediacetate and polycaprolactone/thermoplastic starch. The process of meltblowing requires lower molecular weight and narrow molecular weight distribution resins to produce uniform, fine-fiber webs. The polymer distribution is inversely proportional to the melt flow rate and directly related to the melt viscosity. The processing conditions and general observations will be explained. The physical properties and parameters such as fiber diameter, fiber diameter distribution and stress-strain properties of the webs were measured. Also, microscopical analysis of the meltblown fabric will be shown. These tests give first hints for the processability of such materials with the meltblown process.

Investigation of Crystallinity, Molecular Weight Change, and Mechanical Properties of PLA/PBG Bioresorbable Composites as Bone Fracture Fixation Plates

2010 ◽  
Vol 26 (7) ◽  
pp. 765-789 ◽  
Author(s):  
Reda M. Felfel ◽  
Ifty Ahmed ◽  
Andrew J. Parsons ◽  
Papia Haque ◽  
Gavin S. Walker ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Flexural Modulus ◽  
Phosphate Buffer Solution ◽  
Xrd Analysis ◽  
Chain Scission ◽  
Short Fiber ◽  
Poly Lactic Acid ◽  
Buffer Solution ◽  
Fiber Volume ◽  
Pull Out

In this study, bioresorbable phosphate-based glass (PBG) fibers were used to reinforce poly(lactic acid) (PLA). PLA/PBG random mat (RM) and unidirectional (UD) composites were prepared via laminate stacking and compression molding with fiber volume fractions between 14% and 18%, respectively. The percentage of water uptake and mass change for UD composites were higher than the RM composites and unreinforced PLA. The crystallinity of the unreinforced PLA and composites increased during the first few weeks and then a plateau was seen. XRD analysis detected a crystalline peak at 16.6° in the unreinforced PLA sample after 42 days of immersion in phosphate buffer solution (PBS) at 37°C. The initial flexural strength of RM and UD composites was ∼106 and ∼115 MPa, whilst the modulus was ∼6.7 and ∼9 GPa, respectively. After 95 days immersion in PBS at 37°C, the strength decreased to 48 and 52 MPa, respectively as a result of fiber–matrix interface degradation. There was no significant change in flexural modulus for the UD composites, whilst the RM composites saw a decrease of ∼45%. The molecular weight of PLA alone, RM, and UD composites decreased linearly with time during degradation due to chain scission of the matrix. Short fiber pull-out was seen from SEM micrographs for both RM and UD composites.

scholarly journals Noncovalent Sericin-Chitosan Scaffold: Physical Properties and Low Cytotoxicity Effect

2020 ◽  
Vol 21 (3) ◽  
pp. 775 ◽  
Author(s):  
Rungsima Chollakup ◽  
Pimporn Uttayarat ◽  
Arkadiusz Chworos ◽  
Wirasak Smitthipong
Keyword(s):  
Molecular Weight ◽  
Physical Properties ◽  
Textile Industry ◽  
Phosphate Buffer Solution ◽  
The Self ◽  
Buffer Solution ◽  
Chitosan Scaffold ◽  
Naoh Solution ◽  
Self Assembled ◽  
Low Cytotoxicity

This research aims to utilize sericin, which is the waste from boiling silk cocoon, for the supramolecular scaffold preparation with chitosan. A suitable method for the self-assembled scaffold formation of sericin and chitosan at 1:1 stoichiometry is presented and the morphological and physical properties of the scaffold are studied. The effect of an alcohol/NaOH solution on the secondary structure of sericin protein within the sericin-chitosan scaffold, with adjusted pH, was investigated. Additionally, the scaffold was tested in a native phosphate buffer solution (PBS). The results show that sericin increases the porosity of scaffold while chitosan increases the rigidity. The self-assembled sericin and chitosan material is nontoxic to human cells and which can adhere and spread well on such support. For the effect of the molecular weight of chitosan (15,000 and 100,000 g/mol), the scaffold made from lower molecular weight (MW) chitosan provides a somewhat smaller porosity, but a similar swelling ratio and water uptake. On the basis of this research, sericin, which is a silk waste from the textile industry, can be utilized to produce a self-assembled scaffold with chitosan in order to increase the porosity of the scaffold. This type of scaffold is not toxic and can be used for the adhesion of fibroblast cells.

scholarly journals Study of Ethyl Cellulose Based Sustained Release Microspheres of Naproxen Sodium

2012 ◽  
Vol 10 (2) ◽  
pp. 123-129 ◽  
Author(s):  
Kowshik Sarkar ◽  
Sams Mohammad Anowar Sadat ◽  
Md Saiful Islam ◽  
Reza-ul Jalil
Keyword(s):  
Surface Morphology ◽  
Sustained Release ◽  
Ethyl Cellulose ◽  
Naproxen Sodium ◽  
Drug Loading ◽  
Phosphate Buffer Solution ◽  
Buffer Solution ◽  
Peg 6000 ◽  
Peg 600 ◽  
Sustained Release Microspheres

The present study was conducted to prepare sustained release microspheres of naproxen sodium using ethyl cellulose (Ethocel 20 cps) polymer. Three different plasticizers namely polyethyleneglycol 600   (PEG 600), polyethyleneglycol 6000 (PEG 6000) and triethyl citrate (TEC) were used at 10% (wt/wt) and 40% (wt/wt) level of the drug content. Prepared microspheres were characterized with respect to drug loading,   microsphere particle size, microsphere surface morphology and release behavior. Surface morphology of the microspheres was examined in a scanning electron microscope. Drug release was observed in phosphate buffer   solution of pH 6.8 for 8 hours. At 10% level of the plasticizers, percent release was 93.36%, 93.02% and   92.67% for PEG 600, PEG 6000 and TEC respectively after 8 hours. On the other hand, at 40% level, percent   release was 81.12%, 70.06% and 51.12% for PEG 600, PEG 6000 and TEC respectively after the same   duration. Release mechanisms followed case I or fickian model   DOI: http://dx.doi.org/10.3329/dujps.v10i2.11792   Dhaka Univ. J. Pharm. Sci. 10(2): 123-129, 2011 (December)  

Τhe effect of silica nanoparticles on the thermomechanical properties and degradation behavior of polylactic acid

2014 ◽  
Vol 29 (5) ◽  
pp. 662-674 ◽  
Author(s):  
P Georgiopoulos ◽  
E Kontou ◽  
A Meristoudi ◽  
S Pispas ◽  
M Chatzinikolaidou
Keyword(s):  
Molecular Weight ◽  
Silica Nanoparticles ◽  
Polylactic Acid ◽  
Weight Reduction ◽  
Thermomechanical Properties ◽  
Size Exclusion ◽  
Degradation Behavior ◽  
Buffer Solution ◽  
Melt Mixing ◽  
Aging Conditions

In this work a series of polylactic acid/SiO2 nanocomposites have been prepared by a melt mixing procedure. The dispersion quality was examined by scanning electron microscopy. To study the degradation behavior of the polylactic acid/nanocomposites prepared, the samples were immersed in a buffer solution at a temperature of 37℃ with a pH of 7.4 for a time period of up to 23 weeks. These conditions simulate those in the human body, appropriate in medical applications. In order to assess their suitability in biomedical applications, we investigated the biocompatibility of these materials in terms of cell viability, growth, and morphology. A good initial cell adhesion has been detected, supporting their potential use in bone tissue engineering applications. The hydrolytic degradation of polylactic acid, under the prescribed conditions, was studied by the molecular weight reduction in terms of size exclusion chromatography, whereas the progress of thermal stability of polylactic acid and polylactic acid/nanocomposites during aging was tested by thermogravimetric analysis. The evolution of the materials’ thermomechanical properties during aging was studied by differential scanning calorimetry, dynamic mechanical analysis, and tensile testing. The crystallization behavior in polylactic acid and the way it is affected by the presence of nanofillers during degradation procedure has been studied and values of 44% crystallinity increment have been found. At the specific aging conditions studied, silica nanoparticles accelerate the degradability of polylactic acid, having a higher impact on Young’s modulus, under the specified aging conditions, for 7 weeks and hereafter this acceleration is retarded, due to the crystallinity increment, as a result of the molecular weight reduction.

The Study of Using TiO2 Nanotube Arrays as a Drug Delivery for Alendronate

2011 ◽  
Vol 335-336 ◽  
pp. 1469-1472 ◽  
Author(s):  
Chun Yan Wang ◽  
Xiu Feng Xiao ◽  
Dan Mao ◽  
Hai Zhen Tang ◽  
Rong Fang Liu
Keyword(s):  
Sustained Release ◽  
Phosphate Buffer Solution ◽  
Hollow Structure ◽  
Titanium Substrate ◽  
Nanotube Arrays ◽  
Burst Release ◽  
X Ray Diffraction ◽  
Buffer Solution ◽  
Vertically Aligned ◽  
Two Stages

TiO2 nanotube arrays possess regular hollow structure, large specific surface area and good biocompatibility, which are good for filling with drugs. In this paper, a vertically aligned nanotube arrays of titanium oxide was fabricated on the surface of titanium substrate in fluoride-containing electrolytes by anodization. The TiO2 nanotube arrays were loaded with alendronate via vacuum drying method and the release of alendronate from the nanotubes were detected in phosphate buffer solution(PBS). The samples were characterized by scanning electronic microscope(SEM), X-ray diffraction(XRD), Fourier transform infrared(FTIR), Thermogravimetric analysis (TG) and visible ultraviolet spectrophotometer(UV-vis). The data showed that the release of alendronate from the nanotubes includes two stages: burst release and sustained release, the result indicated that the drug loaded in the TiO2 nanotubes has a certain amounts of sustained-release effect.

Reconstruction of Two-Dimensional Projections of GP 32*I

1981 ◽  
Vol 39 ◽  
pp. 38-39
Author(s):  
H.A. Cohen ◽  
W. Chiu ◽  
J. Hosoda
Keyword(s):  
Electron Microscopy ◽  
Molecular Weight ◽  
Uranyl Acetate ◽  
Distilled Water ◽  
Acetate Solution ◽  
Two Dimensional ◽  
Parent Molecule ◽  
T4 Bacteriophage ◽  
Electron Imaging ◽  
Better Than

GP 32 (molecular weight 35000) is a T4 bacteriophage protein that destabilizes the DNA helix. The fragment GP32*I (77% of the total weight), which destabilizes helices better than does the parent molecule, crystallizes as platelets thin enough for electron diffraction and electron imaging. In this paper we discuss the structure of this protein as revealed in images reconstructed from stained and unstained crystals.Crystals were prepared as previously described. Crystals for electron microscopy were pelleted from the buffer suspension, washed in distilled water, and resuspended in 1% glucose. Two lambda droplets were placed on grids over freshly evaporated carbon, allowed to sit for five minutes, and then were drained. Stained crystals were prepared the same way, except that prior to draining the droplet, two lambda of aqueous 1% uranyl acetate solution were applied for 20 seconds. Micrographs were produced using less than 2 e/Å2 for unstained crystals or less than 8 e/Å2 for stained crystals.

Detection of Hepatitis a Virus in Drinking Water by Enzyme -Immunoassay Using Ultracentrifugation for Virus Concentration

1985 ◽  
Vol 17 (10) ◽  
pp. 39-41 ◽  
Author(s):  
A. Schnattinger
Keyword(s):  
Membrane Filtration ◽  
Hepatitis A ◽  
Hepatitis A Virus ◽  
Solid Phase ◽  
Phosphate Buffer Solution ◽  
Enzyme Linked Immunosorbent Assay ◽  
Virus Concentration ◽  
Buffer Solution ◽  
Solution Ph ◽  
Two Stage

Ten litres of tapwater were seeded with 200 µl (8×108 HAV particles) of a commercial (Organon Teknika) suspension of hepatitis A virus. Following WALTER and RÜDIGER (1981), the contaminated tapwater was treated with a two-stage technique for concentration of viruses from solutions with low virus titers. The two-stage technique consists of aluminium hydroxideflocculation (200 mg/l Al2(SO4)3. 18 H2O, pH 5,4-5,6) as first stage, the second stage of a lysis of aluminium hydroxidegel with citric acid/sodium citrate-buffer (pH 4,7; 1 ml/l sample), separation of viruses from the lysate by ultracentrifugation and suspension in 1 ml phosphate buffer solution (pH 7,2). A commercial solid phase enzyme-linked immunosorbent assay (ELISA) was used for the detection of HAV. HAV was detecterl in the 10.000:1 concentrates, but not in the seeded 101 samples. Approximately 4×108 of the inoculated 8×108 HAV particles were found in the 1 ml concentrates. The efficiency of detection is about 50%, the virus concentration 5000-fold. Although the percentage loss of HAV in comparison with concentration by means of membrane filtration is similar, the ultracentrifugation method yields a larger sample/concentrate ratio, so that smaller amounts of HAV can be detected more efficiently because of the smaller end-volume.

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