Ultrasonic modification of polylactic acid and polyglycolic acid acupoint catgut embedding monofilaments for juvenile pseudomyopia

2018 ◽  
Vol 89 (17) ◽  
pp. 3556-3566 ◽  
Author(s):  
Shaoju Fu ◽  
Dongchao Yang ◽  
Cunyi Zhao ◽  
Peihua Zhang
Keyword(s):  
Mechanical Properties ◽  
Polylactic Acid ◽  
High Efficiency ◽  
Cell Attachment ◽  
Polyglycolic Acid ◽  
Molecular Structures ◽  
Ultrasonic Power ◽  
Mixed Solution ◽  
Ultrasonic Modification

Acupoint catgut embedding therapy (ACET) has become the most promising method for treatment of juvenile pseudomyopia due to its advantages of lasting effect, high efficiency, safety and no side effects. However, poor hydrophilicity and biocompatibility are the main disadvantages, preventing ACET materials from having wide applications. This work fabricated four types of polylactic acid (PLA) and polyglycolic acid (PGA) monofilaments from their polymer chips, and then the prepared monofilaments were treated ultrasonically by dipping them in a mixed solution composed of ethyl alcohol and H2O2(volume ratio 1:1) at 250 W ultrasonic power for 30 min. Afterwards, the PLA and PGA groups were fully characterized with respect to structure characterizations, mechanical properties and in vitro properties. The results showed that the surface roughness of the monofilaments had been greatly enhanced by ultrasonic modification. The PLA groups’ molecular structures changed little, while those of the PGA group emerged with some polar hydrophilic bonds. By deionized water measurement of contact angle values, the ultrasound modified PLA monofilaments (UMPLA1 = 87.2 ± 2.5°, UMPLA2 = 83.6 ± 3.5°) presented a decrease compared to that of untreated PLA ones (PLA1 =103.5 ± 3.4°, PLA2 = 108.4 ± 1.2°), while that of ultrasound modified PGA monofilaments (UMPGA1 = 75.6 ± 4.3°, UMPGA2 =70.5 ± 3.1°) was smaller than untreated PGA ones (PGA1 = 97.3 ± 1.7°, PGA2 = 95.8 ± 2.6°). Based on the measurement of the mechanical properties, the tensile properties and bending stiffness of the PLA and PGA groups changed little, and their swelling ratios were greatly improved after modification. All the prepared monofilaments presented non-toxicity with good cell viability (more than 75%), and samples UMPGA2 (81.4 ± 3.1%) and UMPLA2 (65.8 ± 0.8%) exhibited the largest cell attachment ratio values among their groups. In conclusion, these findings present important clinical implications regarding the ACET materials manufacturing process, which warrant further study.

Ammonium hydroxide modification of polylactic acid and polyglycolic acid monofilaments for acupoint catgut embedding therapy

2020 ◽  
Vol 90 (17-18) ◽  
pp. 2109-2119
Author(s):  
Shaoju Fu ◽  
Yao Lu ◽  
Peihua Zhang
Keyword(s):  
Surface Modification ◽  
Polylactic Acid ◽  
Cell Attachment ◽  
Ammonium Hydroxide ◽  
Polyglycolic Acid ◽  
Embedding Therapy ◽  
Surface Modified ◽  
Future Work ◽  
Wide Usage

Polylactic acid (PLA) and polyglycolic acid (PGA) monofilaments have attracted much attention for their wide usage in acupoint catgut embedding therapy (ACET). Their application is restricted, however, by their poor hydrophilicity and cell attachment properties. In this study, PLA and PGA monofilaments were produced from polymer chips, and then modified by the application of an ammonium hydroxide solution to the surface. The modified PLA and PGA monofilaments were fully characterized with respect to their structural, mechanical, and in-vitro properties. The results showed that the surface roughness and hydrophilicity of the materials were greatly increased; surface modified samples of both materials exhibited the smallest contact angle values: 79.2° ± 2.5° (sample PLA2) and 75.9° ± 1.4° (sample PGA2). The weights and diameters and the tensile and flexibility properties of the materials changed little with surface modification, but their swelling ratios increased significantly. All the prepared samples were non-toxic (more than 75% of cells being viable). Surface modification also enhanced cell attachment: PLA2 (48.15% ± 2.16%) and PGA2 (59.43% ± 3.18%) showed the largest cell attachment values (cultured for 48 h) among the samples. In summary, the study proves the feasibility of ammonium hydroxide modification of PLA and PGA, which is beneficial for guiding future work on developing functional PLA or PGA materials for ACET.

Surface modification of polylactic acid (PLA) and polyglycolic acid (PGA) monofilaments via the cold plasma method for acupoint catgut-embedding therapy applications

2019 ◽  
Vol 89 (18) ◽  
pp. 3839-3849 ◽  
Author(s):  
Shaoju Fu ◽  
Peihua Zhang
Keyword(s):  
Surface Modification ◽  
Polylactic Acid ◽  
Cold Plasma ◽  
Cell Attachment ◽  
Polyglycolic Acid ◽  
Oxygen Plasma Treatment ◽  
Plasma Method ◽  
Embedding Therapy ◽  
Good Cell

Polylactic acid (PLA) and polyglycolic acid (PGA) monofilaments have been the most recently, widely used acupoint catgut-embedding therapy (ACET) biodegradable materials. However, their poor hydrophilicity and cell adhesion are common limitations during applications. To improve their surface properties, modification technologies should be generally applied. This paper firstly adapted polymer chips to produce four types of PLA and PGA monofilaments, and then attempted cold oxygen plasma treatment for surface modification. Afterwards, the modified monofilaments were fully characterized with respect to structure, mechanical and in vitro properties. The results showed that both the PLA and PGA monofilaments became coarser after modification, and their hydrophilicity was improved, while their weight and diameter sizes were slightly decreased. The tensile properties and flexibility of the modified samples changed little, and their swelling ratio increased sharply. All the prepared samples exhibited good cell viability, with more than 75% of cells being viable. Sample PM-PLA2 (plasma-modified PLA2) and sample PM-PGA2 (plasma-modified PGA2) presented the largest cell attachment ratio (cultured for 48 h) at 52.16% ± 1.05% and 58.39% ± 2.07%, respectively. In sum, this cold plasma method successfully improved the hydrophilicity and in vitro properties of PLA and PGA monofilaments, while retaining the other excellent properties, and warrants further study to develop new PLA and PGA-embedding materials with outstanding clinical efficacy.

scholarly journals Improved Bioactivity of 3D Printed Porous Titanium Alloy Scaffold with Chitosan/Magnesium-Calcium Silicate Composite for Orthopaedic Applications

Materials ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 203 ◽  
Author(s):  
Chun-Hao Tsai ◽  
Chih-Hung Hung ◽  
Che-Nan Kuo ◽  
Cheng-Yu Chen ◽  
Yu-Ning Peng ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Calcium Silicate ◽  
Cell Attachment ◽  
Three Dimensional ◽  
Bone Defects ◽  
Metal Alloys ◽  
Potential Candidate ◽  
Natural Bone

Recently, cases of bone defects have been increasing incrementally. Thus, repair or replacement of bone defects is gradually becoming a huge problem for orthopaedic surgeons. Three-dimensional (3D) scaffolds have since emerged as a potential candidate for bone replacement, of which titanium (Ti) alloys are one of the most promising candidates among the metal alloys due to their low cytotoxicity and mechanical properties. However, bioactivity remains a problem for metal alloys, which can be enhanced using simple immersion techniques to coat bioactive compounds onto the surface of Ti–6Al–4V scaffolds. In our study, we fabricated magnesium-calcium silicate (Mg–CS) and chitosan (CH) compounds onto Ti–6Al–4V scaffolds. Characterization of these surface-modified scaffolds involved an assessment of physicochemical properties as well as mechanical testing. Adhesion, proliferation, and growth of human Wharton’s Jelly mesenchymal stem cells (WJMSCs) were assessed in vitro. In addition, the cell attachment morphology was examined using scanning electron microscopy to assess adhesion qualities. Osteogenic and mineralization assays were conducted to assess osteogenic expression. In conclusion, the Mg–CS/CH coated Ti–6Al–4V scaffolds were able to exhibit and retain pore sizes and their original morphologies and architectures, which significantly affected subsequent hard tissue regeneration. In addition, the surface was shown to be hydrophilic after modification and showed mechanical strength comparable to natural bone. Not only were our modified scaffolds able to match the mechanical properties of natural bone, it was also found that such modifications enhanced cellular behavior such as adhesion, proliferation, and differentiation, which led to enhanced osteogenesis and mineralization downstream. In vivo results indicated that Mg–CS/CH coated Ti–6Al–4V enhances the bone regeneration and ingrowth at the critical size bone defects of rabbits. These results indicated that the proposed Mg–CS/CH coated Ti–6Al–4V scaffolds exhibited a favorable, inducive micro-environment that could serve as a promising modification for future bone tissue engineering scaffolds.

scholarly journals Mechanical and electrical properties of polylactic acid/carbon nanotube composites by rolling process

2018 ◽  
Vol 25 (5) ◽  
pp. 891-901 ◽  
Author(s):  
Lijun Wang ◽  
Jianhui Qiu ◽  
Eiichi Sakai
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotube ◽  
Electrical Properties ◽  
Polylactic Acid ◽  
Molecular Orientation ◽  
Rolling Direction ◽  
Rolling Process ◽  
Molecular Structures ◽  
Scanning Calorimetry ◽  
Mechanical And Electrical Properties

AbstractIn this work, the rolling process was employed to fabricate polylactic acid/multi-walled carbon nanotube (PLA/MWCNT) composites at room temperature. The effects of the rolling conditions on the mechanical and electrical properties of the fabricated composites were investigated. The evolution processes of the internal molecular structures, i.e. changes in molecular orientation and crystallinity, were examined by X-ray diffraction, differential scanning calorimetry, and density method. The results suggested that the molecular orientation improved; however, the crystallinity decreased when the rolling ratio increased. The analysis of the mechanical properties revealed that the rolled composites displayed anisotropy during the rolling process. In the rolling direction, after adding 1 wt.% MWCNTs, the tensile strength increased from 58.6 to 94.3 MPa with the rolling ratio, whereas the fracture strain sharply increased to 131.5% at the rolling ratio of 60%. In addition to the mechanical properties, electrical resistivity was also investigated; notably, this property was not significantly affected by the rolling process. Furthermore, the MWCNT dispersion and morphology were investigated by scanning electron microscopy. These findings offer a simple and effective method to fabricate conductive composites with excellent mechanical properties.

scholarly journals DEGRADASI POLIBLEND POLI(ASAMLAKTAT-KO-ASAMGLIKOLAT) DENGAN POLI(ε-KAPROLAKTON) SECARA IN VITRO

2015 ◽  
Vol 2 (2) ◽  
pp. 174
Author(s):  
Tetty Kemala ◽  
Achmad Sjahriza ◽  
Hendra Adijuwana ◽  
Mardiana Hardianti
Keyword(s):  
Lactic Acid ◽  
Polylactic Acid ◽  
Intrinsic Viscosity ◽  
Phosphate Buffer ◽  
Glycolic Acid ◽  
Incubation Temperature ◽  
Human Life ◽  
Polyglycolic Acid ◽  
Poly Lactic Acid

 ABSTRACT  Polymer has many applications in human life, one of them is in the field of health. Polymer synthetics like polylactic acid (PLA), polyglycolic acid (PGA), poly(ε-caprolactone) (PCL), and poly(lactic acid-co-glycolic acid) (PLGA) were kind of polyesters that is many used in field   of health. Many researchers have already made research about degradation of PLA, PGA, PCL, and PLGA. However, there is no one doing research about degradation of combination between this two polymers, one of them is polyblend of  PLGA and PCL. Polyblend were made of four compositions, that were PLGA(90:10):PCL 3:1, PLGA(75:25):PCL 3:1, PLGA(90:10):PCL 5:1, and PLGA(75:25):PCL 5:1. Degradation was carried out for eight weeks by using phosphate buffer pH 7.4 and incubation temperature of 37°C. Degradation of the polymer was observed by mass remained, and intrinsic viscosity. The result showed that composition PLGA(75:25):PCL 5:1 was the fastest in degradation compared to other compositions. It was showed by the decrease in mass until 89.06% and the change in intrinsic viscosity until 20.13%. Keywords: PLGA, PCL   

Polylactic Acid/Halloysite Nanotubes-Titanium Dioxide Nanocomposites: Antibacterial and Mechanical Properties

2021 ◽  
Vol 1021 ◽  
pp. 270-279
Author(s):  
Abdulkader M. Alakrach ◽  
Awad A. Al-Rashdi ◽  
Taha Alqadi ◽  
Mohammed Abdulhakim Al Saadi ◽  
Sam Sung Ting ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Polylactic Acid ◽  
High Efficiency ◽  
Antibacterial Effect ◽  
Control Sample ◽  
Antibacterial Properties ◽  
Halloysite Nanotubes ◽  
Solution Casting ◽  
Elapsed Time ◽  
Solution Casting Method

Polylactic acid (PLA) nanocomposite samples with different properties like mechanical, thermal, barrier and antibacterial properties are good candidates as packaging biomaterials. Unique PLA/TiO2 and PLA/HNTs-TiO2 nanocomposite samples were fabricated by solution casting method. The mechanical and antibacterial properties of PLA/TiO2 and PLA/HNTs-TiO2 samples were investigated with comparing to the pristine PLA film as a control sample. PLA nanocomposite samples with TiO2 nanofillers showed poorer mechanical properties while PLA films with PLA/HNTs-TiO2 showed unique developments, which tensile strength improved by 46% with the incorporation of 5 wt%. The PLA nanocomposites showed a high efficiency to both Gram positive and Gram negative bacteria, significant antibacterial effect being proved after first week elapsed time by comparing to the control sample (presenting no antibacterial effect). By considering the multifunctional characteristics of PLA/TiO2 and PLA/HNTs-TiO2 nanocomposites, the samples produced by solution casting can be considered a favourable alternative as environmental-friendly packaging materials.

Fabrication and evaluation of polylactic acid/pectin composite scaffold via freeze extraction for tissue engineering

2020 ◽  
Vol 40 (5) ◽  
pp. 421-431
Author(s):  
Mohd Syahir Anwar Hamzah ◽  
Saiful Izwan Abd Razak ◽  
Mohammed Rafiq Abdul Kadir ◽  
Siti Pauliena Mohd Bohari ◽  
Nadirul Hasraf Mat Nayan ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Polylactic Acid ◽  
Cell Attachment ◽  
Porous Scaffold ◽  
Composite Scaffold ◽  
Engineering Material ◽  
Water Contact ◽  
Good Biocompatibility ◽  
Proliferation In Vitro

AbstractThis work reports the fabrication and characterizations of porous scaffold made up of polylactic acid (PLA) with the inclusion of pectin (1, 3, 5, 7, 9, 11 wt%) for potential tissue engineering material. The composite scaffold was prepared using a facile method of freeze extraction. Based on the physical evaluations, the scaffold was suggested to be optimum at 5 wt% of pectin loading. Water contact angle of the scaffold was significantly reduced to 46.5o with the inclusion of 5 wt% of pectin. Morphological and topographic of the PLA scaffold revealed that the pectin induced more porous structure and its surface became rougher which was suitable for cell attachment and proliferation. In vitro studies of the PLA/pectin composite scaffold using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromidelt (MTT) assay revealed good biocompatibility whereas Live-Dead kit assay resulted in 91% cell viability after 7 days of incubation.

scholarly journals Biocompatibility of electrospinning polycaprolactone, polylactic acid, their blends and copolymers scaffolds in in vitro tests if mesenchyme stem cells

2021 ◽  
Vol 8 (5) ◽  
pp. 38-49
Author(s):  
A. I. Mishanin ◽  
A. N. Panina ◽  
E. N. Bolbasov ◽  
S. I. Tverdokhlebov ◽  
A. S. Golovkin
Keyword(s):  
Stem Cells ◽  
Polylactic Acid ◽  
Biodegradable Polymers ◽  
In Vitro Study ◽  
Polyglycolic Acid ◽  
In Vitro Tests ◽  
Adhesion Properties ◽  
Acid Copolymer ◽  
Mesenchyme Stem Cells

Background. Biodegradable polymers are one of the most promising groups of materials suitable for creating tissue-engineered scaffolds. The high interest in biopolymers is associated with the possibility of creating scaffolds with desired properties, through the use of mixtures and copolymers. The determination of the key parameters of biocompatibility is the basic purpose for testing created materials.Objective. To perform the comparative in vitro study of biocompatibility properties of biopolymer scaffolds produced using polycaprolactone, polylactic acid, their mixtures and copolymers by electrospinning technology.Design and methods. The adhesion properties and cytotoxicity of scaffolds made from polycaprolactone, polylactic acid, copolymer of L- and D-isoforms of lactic acid, their mixtures and co-polymers with the addition of polyglycolic acid were investigated after scaffolds co-cultivation with human mesenchyme stem cells (MSC).Results. The largest number of spread spindle-shaped MSCs was on the surface of polymers containing polyglycolic acid. Besides, the cells on the surface of the copolymer with polyglycolic acid had the morphology closest to the control. The lowest number of living cells was found on the surface of polylactic acid scaffolds, and the highest on the surface of samples from of polycaprolactone and polylactic acid blend.Conclusion. Thus, all tested polymers had good adhesion properties in experiments with human mesenchyme stem cells were possessed by biodegradable polymers with the addition of polyglycolic acid. 

scholarly journals Suppression Technique of HeLa Cell Proliferation Using Ultrasonic Power Amplifiers Integrated with a Series-Diode Linearizer

Sensors ◽  
2018 ◽  
Vol 18 (12) ◽  
pp. 4248 ◽  
Author(s):  
Se-woon Choe ◽  
Hojong Choi
Keyword(s):  
Cell Density ◽  
Power Amplifier ◽  
Power Amplifiers ◽  
Cell Attachment ◽  
Statistical Significance ◽  
Control Group ◽  
Ultrasonic Power ◽  
Suppression Technique ◽  
Experimental Group

A series-diode linearizer scheme is developed, which can possibly generate higher voltage signals. To verify our proposed concept, ultrasonic power amplifiers with and without the linearizer were tested for HeLa cells proliferation in vitro. In general, ultrasonic stimulus initiates the process of cavitation which can cause cell lysis and disruption of cell attachment. The cavitation can also induce formation of free radicals so that a rigid membrane of malignant cancer cells have increased sensitivity to ultrasonic stimulus. The cell density of the control group increased up to almost 100% on Day 3. However, cell densities of the experimental group when using an isolated ultrasonic power amplifier, and ultrasonic power amplifiers integrated with the linearizer at 1 V and 5 V DC (direct current) bias could be suppressed more than that when using an ultrasonic power amplifier (90.7 ± 1.2%, 75.8 ± 3.5%, and 68.1 ± 1.1%, respectively). Additionally, the proliferation suppressing ratios of each experimental group confirmed that the cell density decrements of the experimental groups exhibited statistical significance compared to the control group (ultrasonic power amplifier = 8.87%, ultrasonic power amplifier with 1 V biased linearizer = 23.87%, and ultrasonic power amplifier with 5 V biased linearizer = 31.56%).

scholarly journals Development, Characterization and In Vitro Biological Properties of Scaffolds Fabricated From Calcium Phosphate Nanoparticles

2019 ◽  
Vol 20 (7) ◽  
pp. 1790 ◽  
Author(s):  
Lizette Morejón ◽  
José Angel Delgado ◽  
Alexandre Antunes Ribeiro ◽  
Marize Varella de Oliveira ◽  
Eduardo Mendizábal ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mineral Composition ◽  
Cell Attachment ◽  
Sintering Temperature ◽  
Calcium Phosphates ◽  
Total Porosity ◽  
Biological Properties ◽  
Solid Content ◽  
Native Bone

Ceramic materials mimic the mineral composition of native bone and feature osteoconductive properties; they are therefore used to regenerate bone tissue. Much research focuses on increasing the porosity and pore interconnectivity of ceramic scaffolds to increase osteoconductivity, cell migration and cell-cell interaction. We aimed to fabricate biocompatible 3D-scaffolds featuring macro- and microporous calcium phosphates with high pore interconnection. Nanoparticles of hydroxyapatite (HA) and calcium deficient hydroxyapatite (CDHA) were synthesized by wet chemical precipitation. Scaffolds were produced from them by the replication polymeric foam technique. Solid content and sintering temperature were varied. Nanoparticles and scaffolds were characterized regarding morphology, chemical and mineral composition, porosity and mechanical properties. Biocompatibility, cell attachment and distribution were evaluated in vitro with human adipose mesenchymal stem cells. Scaffolds with total porosity of 71%–87%, pores in the range of 280–550 µm and connectivity density up to 43 mm−3 were obtained. Smaller pore sizes were obtained at higher sintering temperature. High solid content resulted in a decrease of total porosity but increased interconnectivity. Scaffolds 50HA/50β-TCP featured superior interconnectivity and mechanical properties. They were bioactive and biocompatible. High HA solid content (40 wt.%) in the HA pure scaffolds was negative for cell viability and proliferation, while in the 50HA/50β-TCP composite scaffolds it resulted more biocompatible.

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