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https://www.readbyqxmd.com/read/28636337/thermal-annealing-to-modulate-the-shape-memory-behavior-of-a-biobased-and-biocompatible-triblock-copolymer-scaffold-in-the-human-body-temperature-range
#1
Andrea Merlettini, Matteo Gigli, Martina Ramella, Chiara Gualandi, Michelina Soccio, Francesca Boccafoschi, Andrea Munari, Nadia Lotti, Maria Letizia Focarete
A biodegradable and biocompatible electrospun scaffold with shape memory behavior in the physiological temperature range is here presented. It was obtained starting from a specifically designed, biobased PLLA-based triblock copolymer, where the central block is poly(propylene azelate-co-propylene sebacate), (P(PAz60PSeb40)) random copolymer. Shape memory properties are determined by the contemporary presence of the low melting crystals of the P(PAz60PSeb40) block, acting as switching segment, and of the high melting crystal phase of PLLA blocks, acting as physical network...
June 21, 2017: Biomacromolecules
https://www.readbyqxmd.com/read/28636315/fabrication-of-hierarchical-macroporous-biocompatible-scaffolds-by-combining-pickering-high-internal-phase-emulsion-templates-with-three-dimensional-printing
#2
Ting Yang, Yang Hu, Chaoyang Wang, Bernard P Binks
Biocompatible and biodegradable porous scaffolds with adjustable pore structure have aroused increasing interest in bone tissue engineering. Here, we report a facile method to fabricate hierarchical macroporous biocompatible (HmPB) scaffolds by combining Pickering high internal phase emulsion (HIPE) templates with three-dimensional (3D) printing. HmPB scaffolds composed of a polymer matrix of poly(L-lactic acid), PLLA, and poly(ε-caprolactone), PCL, are readily fabricated by solvent evaporation of 3D printed Pickering HIPEs which are stabilized by hydrophobically modified silica nanoparticles (h-SiO2)...
June 21, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28635284/competing-stereocomplexation-and-homocrystallization-of-poly-l-lactic-acid-poly-d-lactic-acid-racemic-mixture-effects-of-miscible-blending-with-other-polymer
#3
Jianna Bao, Xiaojia Xue, Kai Li, Xiaohua Chang, Qing Xie, Chengtao Yu, Pengju Pan
Promoting the stereocomplexation ability of high-molecular-weight poly(L-lactic acid) (PLLA) and poly(D-lactic acid) (PDLA) is an efficient way to improve the thermal resistance of resulted materials. Herein, we studied the competing crystallization kinetics, polymorphic crystalline structure, and lamellae structure of PLLA/PDLA component in its miscible blends with poly(vinyl acetate) (PVAc) and proposed a method to improve the stereocomplexation ability of PLLA and PDLA through miscible blending with the other polymer...
June 21, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28631613/repairing-a-bone-defect-with-a-three-dimensional-cellular-construct-composed-of-a-multi-layered-cell-sheet-on-electrospun-mesh
#4
Zhiwei Ren, Shiqing Ma, Le Jin, Zihao Liu, Deping Liu, Xu Zhang, Qing Cai, Xiaoping Yang
In addition to providing maneuverability, electrospun nanofibrous meshes can make excellent supports for constructing flexible cell sheets to regulate cell behavior by nanofiber features. With the target of bone regeneration, herein composite nanofibers with two different fiber arrangements (nestlike, random) were electrospun from a blend solution containing poly(l-lactide) (PLLA) and gelatin (1:1 in weight ratio). Unlike the non-woven morphology in a random nanofibrous mesh, PLLA/gelatin composite nanofibers in the nestlike nanofibrous mesh displayed both non-woven and parallel morphologies...
June 20, 2017: Biofabrication
https://www.readbyqxmd.com/read/28629034/icariin-immobilized-electrospinning-poly-l-lactide-fibrous-membranes-via-polydopamine-adhesive-coating-with-enhanced-cytocompatibility-and-osteogenic-activity
#5
Hua Liu, Wenling Li, Binghong Luo, Xuexing Chen, Wei Wen, Changren Zhou
In this study, icariin (ICA), one of the main active ingredients of Herba Epimedii for osteogenesis, was applied to functionalize electrospinning poly(l-lactide) (PLLA) fibrous membrane via an intermediate layer of polydopamine (PDA) to obtain enhanced cytocompatibility and osteogenic activity. For this purpose, an array of PDA-coated PLLA fibrous membranes (PLLA-0.5PDA, PLLA-1PDA, PLLA-2PDA, PLLA-5PDA) and ICA-modified PLLA-2PDA fibrous membranes (PLLA-2PDA-10ICA, PLLA-2PDA-20ICA, PLLA-2PDA-40ICA) were successively prepared...
October 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
https://www.readbyqxmd.com/read/28629016/effect-of-stearic-acid-modified-hap-nanoparticles-in-different-solvents-on-the-properties-of-pickering-emulsions-and-hap-plla-composites
#6
Ming Zhang, Ai-Juan Wang, Jun-Ming Li, Na Song
Stearic acid (Sa) was used to modify the surface properties of hydroxyapatite (HAp) in different solvents (water, ethanol or dichloromethane(CH2Cl2)). Effect of different solvents on the properties of HAp particles (activation ratio, grafting ratio, chemical properties), emulsion properties (emulsion stability, emulsion type, droplet morphology) as well as the cured materials (morphology, average pore size) were studied. FT-IR and XPS results confirmed the interaction occurred between stearic acid and HAp particles...
October 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
https://www.readbyqxmd.com/read/28628686/off-face-usage-of-poly-l-lactic-acid-for-body-rejuvenation
#7
Ahmad Jabbar, Suleima Arruda, Neil Sadick
<p>Injectable soft-tissue augmentation agents have become popular alternatives to surgical procedures for the aging face and body. In contrast to temporary, space-occupying replacement fillers such as collagen-based and hyaluronic acid products, poly-l-lactic acid (PLLA) has been demonstrated to gradually promotes deposition of collagen via a biostimulatory response, with therapeutic effects lasting approximately two years. In 2004, the FDA approved its use for rejuvenation of facial contours secondary to lipoatrophy associated with antiretroviral therapy for HIV infection...
May 1, 2017: Journal of Drugs in Dermatology: JDD
https://www.readbyqxmd.com/read/28627315/bioabsorbable-fixation-screw-for-proximal-interphalangeal-arthrodesis-of-lesser-toe-deformities
#8
Jascha Armin Wendelstein, Peter Goger, Peter Bock, Reinhard Schuh, Priv Doz, Hans-Jörg Trnka
BACKGROUND: Although standard fixation of proximal interphalangeal (PIP) arthrodesis by K-wire is relatively inexpensive and well established, it does have some drawbacks, making newer fixation devices interesting. The aim of this study was to clinically and radiologically assess the operative correction of the lesser toe deformation in the form of a PIP arthrodesis using a bioabsorbable 2.7-mm fixation screw. METHODS: From January 2011 until October 2013, 34 patients underwent a PIP arthrodesis using the TRIM-IT (Arthrex) 2...
June 1, 2017: Foot & Ankle International
https://www.readbyqxmd.com/read/28621889/enhanced-skin-regeneration-by-herbal-extract-coated-poly-l-lactic-acid-nanofibrous-scaffold
#9
Aytak Jouybar, Ehsan Seyedjafari, Abdolreza Ardeshirylajimi, Ali Zandi-Karimi, Nikta Feizi, Mohammad-Mehdi Khani, Iraj Pousti
The wound healing process is directly related to the type of treatment. Existing methods of treatment are not responsive enough for severe wounds. The aim of this study was the potential capacity investigation of poly-L-lactic acid (PLLA) nanofibrous scaffolds coated by aloe vera gel for wound dressing applications. In this study, electrospinning method was used for preparing PLLA nanofibers, and after characterization by SEM and MTT, its influence on the wound healing process was investigated with and without aloe vera gel as a wound dressing in full-thickness skin defect in mice...
June 16, 2017: Artificial Organs
https://www.readbyqxmd.com/read/28617909/development-of-a-flow-evolution-network-model-for-the-stress-strain-behavior-of-poly-l-lactide
#10
Maureen L Dreher, Srinidhi Nagaraja, Jorgen Bergstrom, Danika Hayman
Computational modeling is critical to medical device development and has grown in its utility for predicting device performance. Additionally, there is an increasing trend to use absorbable polymers for the manufacturing of medical devices. However, computational modeling of absorbable devices is hampered by a lack of appropriate constitutive models that capture their viscoelasticity and post-yield behavior. The objective of this study was to develop a constitutive model that incorporated viscoplasticity for a common medical absorbable polymer...
June 15, 2017: Journal of Biomechanical Engineering
https://www.readbyqxmd.com/read/28611002/chondrogenesis-of-human-bone-marrow-mesenchymal-stem-cells-in-3-dimensional-photocrosslinked-hydrogel-constructs-effect-of-cell-seeding-density-and-material-stiffness
#11
Aaron X Sun, Hang Lin, Madalyn R Fritch, He Shen, Pete G Alexander, Michael DeHart, Rocky S Tuan
Three-dimensional hydrogel constructs incorporated with live stem cells that support chondrogenic differentiation and maintenance offer a promising regenerative route towards addressing the limited self-repair capabilities of articular cartilage. In particular, hydrogel scaffolds that augment chondrogenesis and recapitulate the native physical properties of cartilage, such as compressive strength, can potentially be applied in point-of-care procedures. We report here the synthesis of two new materials, [poly-l-lactic acid/polyethylene glycol/poly-l-lactic acid] (PLLA-PEG 1000) and [poly-d,l-lactic acid/polyethylene glycol/poly-d,l-lactic acid] (PDLLA-PEG 1000), that are biodegradable, biocompatible (>80% viability post fabrication), and possess high, physiologically relevant mechanical strength (∼1500 to 1800kPa)...
June 10, 2017: Acta Biomaterialia
https://www.readbyqxmd.com/read/28610487/establishment-of-novel-meniscal-scaffold-structures-using-polyglycolic-and-poly-l-lactic-acids
#12
Tomohiko Murakami, Shuhei Otsuki, Kosuke Nakagawa, Yoshinori Okamoto, Tae Inoue, Yuki Sakamoto, Hideki Sato, Masashi Neo
The purpose of this study was to evaluate various types of meniscus scaffolds that mimic the meniscus structure, and to establish a novel cell-free meniscus scaffold with polyglycolic acid or poly-l-lactic acid. Four types of scaffolds were implanted into Japanese white rabbits: poly-l-lactic acid sponge poly-l-lactic acid, PGA-coated PLLA sponge, PGA lamination, and film-coated PGA lamination. Samples were harvested at 8 and 12 weeks after implantation, and a compression stress test was performed. The meniscus size and Ishida scores were evaluated for regenerated tissue...
January 1, 2017: Journal of Biomaterials Applications
https://www.readbyqxmd.com/read/28603415/electroactive-batio3-nanoparticle-functionalized-fibrous-scaffolds-enhance-osteogenic-differentiation-of-mesenchymal-stem-cells
#13
Yiping Li, Xiaohan Dai, Yunyang Bai, Yun Liu, Yuehong Wang, Ousheng Liu, Fei Yan, Zhangui Tang, Xuehui Zhang, Xuliang Deng
It has been proven that the surface topographic cues of fiber arrangement can induce osteogenic differentiation of mesenchymal stem cells. However, this effect alone is weak and insufficient to meet the needs of regenerative medicine. In this work, electroactivity concept was introduced to enhance the osteoinductivity of fibrous scaffolds. The randomly oriented and aligned electroactive fibrous scaffolds of poly-(l-lactic acid) (PLLA) with incorporation of ferroelectric ceramic BaTiO3 (BTO) nanoparticles (NPs) were fabricated by electrospinning...
2017: International Journal of Nanomedicine
https://www.readbyqxmd.com/read/28589918/cryogenic-3d-printing-for-producing-hierarchical-porous-and-rhbmp-2-loaded-ca-p-plla-nanocomposite-scaffolds-for-bone-tissue-engineering
#14
Chong Wang, Qilong Zhao, Min Wang
The performance of bone tissue engineering scaffolds can be assessed through cell responses to scaffolds, including cell attachment, infiltration, morphogenesis, proliferation, differentiation, etc, which are determined or heavily influenced by the composition, structure, mechanical properties, and biological properties (e.g. osteoconductivity and osteoinductivity) of scaffolds. Although some promising 3D printing techniques such as fused deposition modeling and selective laser sintering could be employed to produce biodegradable bone tissue engineering scaffolds with customized shapes and tailored interconnected pores, effective methods for fabricating scaffolds with well-designed hierarchical porous structure (both interconnected macropores and surface micropores) and tunable osteoconductivity/osteoinductivity still need to be developed...
June 7, 2017: Biofabrication
https://www.readbyqxmd.com/read/28587466/tailor-made-dispersion-and-distribution-of-stereocomplex-crystallites-in-poly-l-lactide-elastomer-blends-toward-largely-enhanced-crystallization-rate-and-impact-toughness
#15
Yuanlin Luo, Yilong Ju, Hongwei Bai, Zhenwei Liu, Qin Zhang, Qiang Fu
Stereocomplex (SC) crystallites, formed between poly(l-lactide) (PLLA) and poly(d-lactide), exhibit great potential to substantially enhance crystallization rate of PLLA-based materials as an eco-friendly nucleating agent. However, the nucleation efficiency of the SC crystallites is still far below an expected level, mostly on account of their strong aggregation tendency in PLLA/PDLA melts. Herein, taking PLLA/poly(ethylene-methyl acrylate-glycidyl methacrylate) (E-MA-GMA) blends as an example, we report a unique and facile strategy to control the dispersion and distribution of SC crystallites within the PLLA matrix by using elastomeric E-MA-GMA as carrier for the incorporation of PDLA...
June 16, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28587314/cellular-morphology-mediated-proliferation-and-drug-sensitivity-of-breast-cancer-cells
#16
Ryota Domura, Rie Sasaki, Yuma Ishikawa, Masami Okamoto
The interpretation of the local microenvironment of the extracellular matrix for malignant tumor cells is in intimate relation with metastatic spread of cancer cells involving the associated issues of cellular proliferation and drug responsiveness. This study was aimed to assess the combination of both surface topographies (fiber alignments) and different stiffness of the polymeric substrates (poly(l-lactic acid) and poly(ε-caprolactone), PLLA and PCL, respectively) as well as collagen substrates (coat and gel) to elucidate the effect of the cellular morphology on cellular proliferation and drug sensitivities of two different types of breast cancer cells (MDA-MB-231 and MCF-7)...
June 6, 2017: Journal of Functional Biomaterials
https://www.readbyqxmd.com/read/28575994/plla-microcapsules-combined-with-silver-nanoparticles-and-chlorhexidine-acetate-showing-improved-antibacterial-effect
#17
Yuwei Zhou, Ke Hu, Zhaobin Guo, Kun Fang, Xing Wang, Fang Yang, Ning Gu
In this study, composite antibacterial microcapsules combining of two antibacterial agents: chlorhexidine acetate and silver nanoparticle were prepared. The chlorhexidine acetate was encapsulated inside of the microcapsules and nano-sized silver particles were modified on the surface of microcapsules by electrostatic adsorption methods. Results show that this method decreases the silver usage dramatically, and promises a sustained antibacterial effect >30days. These microcapsules can also be modified on the surface of polymer films easily, which demonstrated the potential in functionalizing the implanted materials with antibacterial property...
September 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
https://www.readbyqxmd.com/read/28575950/in-vitro-proliferation-and-differentiation-of-human-bone-marrow-mesenchymal-stem-cells-into-osteoblasts-on-nanocomposite-scaffolds-based-on-bioactive-glass-64sio2-31cao-5p2o5-poly-l-lactic-acid-nanofibers-fabricated-by-electrospinning-method
#18
M Shamsi, M Karimi, M Ghollasi, N Nezafati, M Shahrousvand, M Kamali, A Salimi
Electrospinning method was employed for fabrication of SiO2-CaO-P2O5 bioactive glass (BG) nanofibers, poly-l-lactic acid (PLLA) nanofibers and nanocomposite scaffolds fabricated from as-prepared nanofibers. Characterization of the prepared nanofibers and scaffolds by XRD, FTIR, and SEM techniques revealed the formation of nanofibers with mean diameter of about 500nm and fully fibrous scaffolds with porous structure and interconnected pores. The growth, viability and proliferation of cultured human bone marrow mesenchymal stem cells in the fabricated nanofibers and bioactive glass-poly-l-lactic acid (BG-PLLA) nanocomposite scaffolds were studied using various biological assays including MTT, ALP activity, calcium deposit content, Alizarin red staining, and RT-PCR test...
September 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
https://www.readbyqxmd.com/read/28574571/roles-of-macrophage-migration-inhibitory-factor-in-cartilage-tissue-engineering
#19
Yuko Fujihara, Atsuhiko Hikita, Tsuyoshi Takato, Kazuto Hoshi
To obtain stable outcomes in regenerative medicine, understanding and controlling immunological responses in transplanted tissues are of great importance. In our previous study, auricular chondrocytes in tissue-engineered cartilage transplanted in mice were shown to express immunological factors, including macrophage migration inhibitory factor (MIF). Since MIF exerts pleiotropic functions, in this study, we examined the roles of MIF in cartilage regenerative medicine. We made tissue-engineered cartilage consisting of auricular chondrocytes of C57BL/6J mouse, atellocollagen gel and a PLLA scaffold, and transplanted the construct subcutaneously in a syngeneic manner...
June 2, 2017: Journal of Cellular Physiology
https://www.readbyqxmd.com/read/28570687/intervention-using-a-novel-biodegradable-hollow-stent-containing-polylactic-acid-polyprolactone-polyethylene-glycol-complexes-against-lacrimal-duct-obstruction-disease
#20
Xinyuan Zhan, Xin Guo, Rong Liu, Weikun Hu, Lei Zhang, Nan Xiang
Lacrimal duct obstruction disease (LDOD) is a common ophthalmologic disease. Stent implantation surgery is one of the most effective therapies. In this study, we intended to find out the satisfactory biodegradable stents containing poly-L-lactic acid-polycaprolactone-polyethylene glycol (PLLA- PCL- PEG) complexes for therapeutic application in LDOD. Stents made of PLLA- PCL- PEG complexes in various ratios, were prepared and used in vitro to determine stents with appropriate mechanical properties and shorter range of bio-degradation for study in vivo...
2017: PloS One
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