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Polylactic Acid

Aubrey L Woern, Dennis J Byard, Robert B Oakley, Matthew J Fiedler, Samantha L Snabes, Joshua M Pearce
Fused particle fabrication (FPF) (or fused granular fabrication (FGF)) has potential for increasing recycled polymers in 3-D printing. Here, the open source Gigabot X is used to develop a new method to optimize FPF/FGF for recycled materials. Virgin polylactic acid (PLA) pellets and prints were analyzed and were then compared to four recycled polymers including the two most popular printing materials (PLA and acrylonitrile butadiene styrene (ABS)) as well as the two most common waste plastics (polyethylene terephthalate (PET) and polypropylene (PP))...
August 12, 2018: Materials
Mercedes Pérez, Gustavo Medina-Sánchez, Alberto García-Collado, Munish Gupta, Diego Carou
The present paper shows an experimental study on additive manufacturing for obtaining samples of polylactic acid (PLA). The process used for manufacturing these samples was fused deposition modeling (FDM). Little attention to the surface quality obtained in additive manufacturing processes has been paid by the research community. So, this paper aims at filling this gap. The goal of the study is the recognition of critical factors in FDM processes for reducing surface roughness. Two different types of experiments were carried out to analyze five printing parameters...
August 8, 2018: Materials
David Encinas-Basurto, Josue Juarez, Miguel A Valdez, Maria G Burboa, Silvia Barbosa, Pablo Taboada
In this study, allyl-isothiocyanate (AITC)-loaded polylactic-co-glycolic acid (PLGA) nanoparticles (NPs) were prepared for targeting epithelial squamous carcinoma cells using a specific antibody targeting the epidermal growth factor (EGF) receptor overexpressed on the cell membranes. AITC-loaded PLGA NPs showed more effective anticancer properties compared with free AITC, and their cytotoxicity was even more pronounced when the anti-EGFR antibody was covalently attached to the NPs surface. This targeting ability was additionally tested by co-culturing cervical HeLa cells, with very few EGFR on the membranes, and epithelial squamous carcinoma A431 cells, which largely overexpressed EFGR, being observed the specific localization of the antibody-functionalized AITC-loaded PLGA NPs solely in the latter types of cells, whereas non-functionalized NPs were distributed randomly in both cell types in much lesser extents...
August 10, 2018: Current Topics in Medicinal Chemistry
Hangxiang Wang, Liqian Zhou, Ke Xie, Jiaping Wu, Penghong Song, Haiyang Xie, Lin Zhou, Jialin Liu, Xiao Xu, Youqing Shen, Shusen Zheng
Nanomedicines have been extensively explored for cancer treatment, and their efficacies have arguably been proven in various cancer cell-derived xenograft (CDX) mouse models. However, they generally fail to show such therapeutic advantages in patients because of the huge pathological differences between human tumors and CDX models. Methods: In this study, we fabricated colloidal ultrastable nanomedicines from polymeric prodrugs and compared the therapeutic efficacies in hepatocellular carcinoma (HCC) CDX and clinically relevant patient-derived xenograft (PDX) mouse models, which closely mimic human tumor pathological properties...
2018: Theranostics
Zichao Wu, Ji Zhao, Wenzheng Wu, Peipei Wang, Bofan Wang, Guiwei Li, Shuo Zhang
Biodegradable stents offer the potential to reduce the in-stent restenosis by providing support long enough for the vessel to heal. The polylactic acid (PLA) vascular stents with negative Poisson's ratio (NPR) structure were manufactured by fused deposition modeling (FDM) 3D printing in this study. The effects of stent diameter, wall thickness and geometric parameters of arrowhead NPR structure on radial compressive property of 3D-printed PLA vascular stent were studied. The results showed that the decrease of stent diameter, the increase of wall thickness and the increase of the surface coverage could enhance the radial force (per unit length) of PLA stent...
August 6, 2018: Materials
Ping Ye, Haitao Yin, Xuelian Gu, Yuanyuan Ye, Qingxiao Zhao, Zhaohua Chang, Baosan Han, Xiaoxiang Chen, Peifeng Liu
AIM: Current cryoablation therapy easily induces a high tumor recurrence, it is therefore necessary to develop an effective method to enhance its antitumor efficacy. MATERIALS & METHODS: We solve the aforementioned problem by introducing doxorubicin (DOX) loading methoxy polyethylene glycol-polylactic-co-glycolic acid-poly-L-lysine-cyclic arginine-glycine-aspartic acid peptide nanoparticles (DOX nanoparticles) in the process of cryoablation. RESULTS: The combination of cryoablation and DOX nanoparticles greatly decreases the recurrence rate of breast cancer, which is owing to the specific targeting therapy of DOX nanoparticles for residuary breast cancer cells after cryoablation...
August 3, 2018: Nanomedicine
Byung Kyu Park, David J Hwang, Dong Eui Kwon, Tae Jun Yoon, Youn-Woo Lee
Multiscale structured polymers have been considered as a promising category of functional materials with unique properties. We combined rapid prototyping and gas foaming technologies to fabricate multiscale functional materials of superior mechanical and thermal insulation properties. Through scanning electron microscope based morphological characterization, formation of multiscale porous structure with nanoscale cellular pores was confirmed. Improvement in mechanical strength is attributed to rearrangement of crystals within CO₂ saturated grid sample...
July 27, 2018: Nanomaterials
Po-Kuei Wu, Yu-Chung Shih, Chao-Ming Chen, Geng Chen, Wei-Ming Chen, Li-Ying Huang, Yu-Cheng Hung, Te-Han Wang, Wen-Chan Yu, Chin-Kang Chang, Bao-Chi Chang, Pei-Hsin Lin, Shyh-Jen Wang
Three-dimensional (3D) printing technology can generate objects in almost any shape and geometry. This technique also has clinical applications, such as the fabrication of specific devices based on a patient's anatomy. A demonstration study is presented of a 54-year-old man who needed a thermoplastic splint to limit arm movement while a dehisced left shoulder wound healed. The patient's upper extremity was scanned using the appropriate noncontact scanner and 3D technology software, and the polylactic acid splint was printed over the course of 66 hours...
July 2018: Ostomy/wound Management
Sang-Ho Ye, Yingqi Chen, Zhongwei Mao, Xinzhu Gu, Venkat Shankarraman, Yi Hong, Vesselin Shanov, William R Wagner
Degradable metallic stents, most commonly comprised of Mg-based alloys, are of interest as an alternative to traditional metallic stents for application in the cardiac and peripheral vasculature. Two major design challenges with such stents are control of the corrosion rate and the acute presentation of a non-thrombogenic surface to passing blood. In this study, several types of sulfobetaine (SB)-bearing biodegradable polyurethanes were developed and assessed as physical, chemical and combination-type coatings for a model degradable Mg alloy, AZ31...
July 30, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
C H Tam, Y C Chan, Y Law, S W Cheng
BACKGROUND: Three-dimensional (3D) printing, also known as rapid prototyping or additive manufacturing, is a novel adjunct in the medical field. The aim of this systematic review is to evaluate the role of 3D printing technology in the field of contemporary vascular surgery in terms of its technical aspect, practicability and clinical outcome. METHODS: A systematic search of literatures published from 1st January 1980 to 15th July 2017 were identified from the EMBASE, MEDLINE and Cochrane library database with reference to the PRISMA guideline...
July 24, 2018: Annals of Vascular Surgery
Tolesa Fita Chala, Chang-Mou Wu, Min-Hui Chou, Zhen-Lin Guo
The development of efficient photothermal materials is the most important issue in solar water evaporation. In this work, melt electrospun reduced tungsten oxide/polylactic acid (WO2.72 /PLA) fiber membranes were successfully prepared with improved near-infrared (NIR) photothermal conversion properties owing to strong NIR photoabsorption by the metal oxide. WO2.72 powder nanoparticles were incorporated into PLA matrix by melt processing, following which the composites were extruded into wires using a single screw extruder...
August 14, 2018: ACS Applied Materials & Interfaces
Juan Carlos Alzate Marin, Sandra Rivero, Adriana Pinotti, Alejandro Horacio Caravelli, N E Zaritzky
Individual films of polyhydroxyalkanoates (PHA) or polylactic acid (PLA) and their blends were developed by solvent casting. PHA was obtained from activated sludges from a wastewater treatment system at laboratory-scale. This work was focused on analyzing the microstructural properties and thermal behavior of either, PHA or PLA individual films as well as their blends. The behavior against biodegradation process of individual films and blends was examined from the microstructural point of view. ATR-FTIR spectra indicated the existence of a weak molecular interaction between the polymers...
July 23, 2018: Journal of Agricultural and Food Chemistry
Sujun Wang, Yanfeng Luo, Jin Zhou, Mingxing Wang, Yuanliang Wang
In this paper, the micro-structure of amphiphilic copolymer Polylactic acid-Polyethylene glycol-Folate (PLA-PEG-FA) was studied firstly by a differential scanning calorimetry (DSC). During the process of nanoparticles (NPs) preparation, we found good inter-structure consistency of polymer was the precondition for forming into stable NPs, and those with micro-phase separation structure were prepared of NPs within limits. Hemolytic test and CCK-8 assay results demonstrated the biotoxicity of both NPs and whose leaching liquor was far below related toxicity standards...
October 1, 2018: Materials Science & Engineering. C, Materials for Biological Applications
Alixandra Wagner, Andrew P White, Man Chio Tang, Sushant Agarwal, Todd A Stueckle, Yon Rojanasakul, Rakesh K Gupta, Cerasela Zoica Dinu
Addition of nanoclays into a polymer matrix leads to nanocomposites with enhanced properties to be used in plastics for food packaging applications. Because of the plastics' high stored energy value, such nanocomposites make good candidates for disposal via municipal solid waste plants. However, upon disposal, increased concerns related to nanocomposites' byproducts potential toxicity arise, especially considering that such byproducts could escape disposal filters to cause inhalation hazards. Herein, we investigated the effects that byproducts of a polymer polylactic acid-based nanocomposite containing a functionalized montmorillonite nanoclay (Cloisite 30B) could pose to human lung epithelial cells, used as a model for inhalation exposure...
July 16, 2018: Scientific Reports
Lukas Raddatz, Marline Kirsch, Dominik Geier, Jörn Schaeske, Kevin Acreman, Rafael Gentsch, Scott Jones, Andreas Karau, Tommy Washington, Meike Stiesch, Thomas Becker, Sascha Beutel, Thomas Scheper, Antonina Lavrentieva
Biodegradable materials play a crucial role in both material and medical sciences and are frequently used as a primary commodity for implants generation. Due to their material inherent properties, they are supposed to be entirely resorbed by the patients' body after fulfilling their task as a scaffold. This makes a second intervention (e.g. for implant removal) redundant and significantly enhances a patient's post-operative life quality. At the moment, materials for resorbable and biodegradable implants (e...
January 1, 2018: Journal of Biomaterials Applications
Ye Xiaolong, Han Xiaoyan, Wei Bo, Huang Jianglong, Yang Xiaofeng, Tang Xiao, Zheng Zongheng, Luo Linbo, Zhan Zefeng, Wei Hongbo
AIM: In the present study, we combined a nanofibrous polylactic acid (PLA) scaffold fabricated by electrospinning with a polypropylene (PP) material to generate a new type of mesh for hernia repair. MATERIALS & METHODS: The PLA/PP mesh was tested with tensile testing, in vitro cytocompatibility and degradation. A total of 90 rats were randomly allocated to PLA/PP, PP and polyester (PE) mesh groups for the in vivo study to evaluate the properties of PLA/PP mesh...
July 12, 2018: Nanomedicine
Gianluca Cicala, Davide Giordano, Claudio Tosto, Giovanni Filippone, Antonino Recca, Ignazio Blanco
Three commercial filaments for Fused Deposition Modeling (FDM) were selected to study the influence of polymer formulation on the printing quality and mechanical properties of FDM specimens. The three filaments were all based on polylactic acid (PLA) as the matrix, and they are sold as PLA filaments. The printing quality was tested by printing one complex shape with overhang features. The marked shear thinning behavior for two filaments was observed by rheology. The filaments were also studied by scanning electron microscopy and thermogravimetric analysis (TGA) to unveil their composition...
July 11, 2018: Materials
Jingjunjiao Long, Ashveen V Nand, Sudip Ray, Sam Mayhew, David White, Craig R Bunt, Ali Seyfoddin
Customisation of sustained and controlled release of contraceptives plays a key role in veterinary applications. A biodegradable projectile containing different doses of contraceptive progesterone was prepared using fused deposition modelling 3D printing. Three concentrations of progesterone (2, 5 and 10% w/w) with polylactic acid was prepared as a 1.75 mm filament by hot melt extrusion. Solvent dissolution tests confirmed the successful incorporation of progesterone in the polymer while microscopic (SEM) studies indicated the drug was melted and thoroughly mixed with the polymer matrix and pore-formation after dissolution...
September 5, 2018: International Journal of Pharmaceutics
Xin Wan, Weiya Pei, Khawar Ali Shahzad, Lei Zhang, Shilong Song, Xiaoxiao Jin, Limin Wang, Chen Zhao, Chuanlai Shen
In this study, a tolerogenic artificial APC (TaAPC) was developed to directly and selectively modulate myelin-autoreactive CD4+ and CD8+ T cells in the myelin oligodendrocyte glycoprotein (MOG)35-55 peptide-induced experimental autoimmune encephalomyelitis in C57BL/6J mice. Cell-sized polylactic-coglycolic acid microparticles were generated to cocouple target Ags (MOG40-54 /H-2Db -Ig dimer, MOG35-55 /I-Ab multimer), regulatory molecules (anti-Fas and PD-L1-Fc), and "self-marker" CD47-Fc and encapsulate inhibitory cytokine (TGF-β1)...
July 9, 2018: Journal of Immunology: Official Journal of the American Association of Immunologists
Prajakta Kulkarni, Manas K Haldar, Fataneh Karandish, Matthew Confeld, Rayat Hossain, Pawel Borowicz, Kara Gange, Lang Xia, Kausik Sarkar, Sanku Mallik
Hypoxia in solid tumors facilitates the progression of the disease, develops resistance to chemo and radiotherapy, and contributes to relapse. Due to the lack of tumor penetration, most of the reported drug carriers are unable to reach the hypoxic niches of the solid tumors. We have developed tissue-penetrating, hypoxia-responsive echogenic polymersomes to deliver anticancer drugs to solid tumors. The polymersomes are composed of a hypoxia-responsive azobenzene conjugated and a tissue penetrating peptide functionalized polylactic acid-polyethylene glycol polymer...
July 2, 2018: Chemistry: a European Journal
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