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https://www.readbyqxmd.com/read/28809474/a-nano-in-nano-approach-for-enzyme-immobilization-based-on-block-copolymers
#1
Finizia Auriemma, Claudio De Rosa, Anna Malafronte, Rocco Di Girolamo, Chiara Santillo, Yuri Gerelli, Giovanna Fragneto, Robert David Barker, Vincenzo Pavone, Ornella Maglio, Angela Lombardi
We have set-up a facile approach for fabrication of supports with tailored nanoporosity for immobilization of enzymes. To this aim block copolymers self-assembly has been used to prepare nanostructured thin films with well-defined architecture containing pores of tailorable size delimited by walls with tailorable degree of hydrophilicity. In particular, we have employed a mixture of polystyrene-block-poly(L-lactide) (PS-PLLA) and polystyrene-block-poly(ethylene oxide) (PS-PEO) diblock copolymers to generate thin films with a lamellar morphology consisting of PS lamellar do-mains alternating with mixed PEO/PLLA blocks lamellar domains...
August 15, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28803028/novel-poly-l-lactide-graphene-oxide-films-with-improved-mechanical-flexibility-and-antibacterial-activity
#2
Zhijun Yang, Chen Sun, Liang Wang, Huixin Chen, Ji He, Yuan Chen
Poly(l-lactic acid) (PLLA) is a biocompatible polyester derived from renewable sources. It is desirable to reduce its brittleness and introduce antibacterial activity for biomedical applications by using graphene oxide (GO) as a structural and antibacterial agent. However, commonly used polymer/GO composite synthesis methods, such as physical mixing and covalent functionalization, either cause phase segregation or compromise the intrinsic properties of GO. Here, a novel approach is demonstrated to synthesize PLLA/GO films...
August 5, 2017: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/28795778/time-dependent-effect-of-electrical-stimulation-on-osteogenic-differentiation-of-bone-mesenchymal-stromal-cells-cultured-on-conductive-nanofibers
#3
Siqi Zhu, Wei Jing, Xiaoqing Hu, Zirong Huang, Qing Cai, Yingfang Ao, Xiaoping Yang
Bone tissue engineering using bone mesenchymal stromal cells (BMSCs) is a multidisciplinary strategy that requires biodegradable scaffold, cell, various promoting cues to work simultaneously. Electrical stimulation (ES) is known able to promote osteogenic differentiation of BMSCs, but it is interesting to know how can it play the strongest promotion effect. To strengthen local ES on BMSCs, parallel-aligned conductive nanofibers were electrospun from the mixtures of poly(L-lactide) (PLLA) and multi-walled carbon nanotubes (MWCNTs), and used for cell culture...
August 10, 2017: Journal of Biomedical Materials Research. Part A
https://www.readbyqxmd.com/read/28782391/in-vitro-expansion-of-cd-133-cells-derived-from-umbilical-cord-blood-in-poly-l-lactic-acid-plla-scaffold-coated-with-fibronectin-and-collagen
#4
Maryam Islami, Yousef Mortazavi, Masoud Soleimani, Samad Nadri
CONTEXT: Due to their renewal and potency, umbilical cord blood (UCB) stem cells have the ability to proliferate and serve as an attractive alternative source for bone marrow transplantation. However, insufficient number of haematopoietic stem cells (HSCs) in UCB is still a major constraint in clinical applications. OBJECTIVE: In vitro expansion of stem cells on fibronectin (Fn)-coated poly-L-lactic acid (PLLA) scaffold can be a proper way to overcome this limitation...
August 6, 2017: Artificial Cells, Nanomedicine, and Biotechnology
https://www.readbyqxmd.com/read/28782240/electrophoretic-deposition-of-mgo-nanoparticles-imparts-antibacterial-properties-to-poly-l-lactic-acid-for-orthopedic-applications
#5
Daniel J Hickey, Divya Muthusamy, Thomas J Webster
Bacterial infection of implanted biomaterials is a serious problem that increases health care costs and negatively affects a considerable fraction of orthopedic procedures. In this field, magnesium oxide nanoparticles (MgO NPs) have emerged as a promising material to combat bacterial infection while maintaining or improving bone cell functions. Here, MgO NPs were electrophoretically deposited onto poly-L-lactic acid (PLLA) sheets to achieve a coating of highly exposed MgO NPs that directly influenced cell-substrate interactions at short time scales...
August 7, 2017: Journal of Biomedical Materials Research. Part A
https://www.readbyqxmd.com/read/28778112/-soft-tissue-fillers-state-of-the-art-and-future-perspectives
#6
Matthias M Aitzetmüller, Inesa Sukhova, Georg M Huemer, Hans-Guenther Machens, Jan-Thorsten Schantz, Dominik Duscher
In addition to cosmetic use, filler materials are frequently employed for reconstruction of contour defects. Scars and tissue defects after accidents, surgery and irradiation are also ideal indications for injectables. The ideal filler should be easy to inject, easy to form, and should remain in the body as long as possible. It should neither be allergenic or carcinogenic nor susceptible to infections or biofilms, but still potentially reversible, temperature-stable, and cheap. There is still no augmentation material that fulfils all of these criteria...
August 4, 2017: Handchirurgie, Mikrochirurgie, Plastische Chirurgie
https://www.readbyqxmd.com/read/28773109/thermomechanical-properties-of-polylactic-acid-graphene-composites-a-state-of-the-art-review-for-biomedical-applications
#7
REVIEW
Ilker S Bayer
Due to its biodegradable and bioabsorbable characteristics polylactic acid (PLA) has attracted considerable attention for numerous biomedical applications. Moreover, a number of tissue engineering problems for function restoration of impaired tissues have been addressed by using PLA and its copolymers due to their biocompatibility and distinctive mechanical properties. Recent studies on various stereocomplex formation between enantiomeric PLA, poly(l-lactide) (PLLA) and poly(d-lactide) (PDLA) indicated that stereocomplexation enhances the mechanical properties as well as the thermal- and hydrolysis-resistance of PLA polymers...
July 4, 2017: Materials
https://www.readbyqxmd.com/read/28770986/coffee-grounds-to-multifunctional-quantum-dots-extreme-nanoenhancers-of-polymer-biocomposites
#8
Huan Xu, Lan Xie, Jinlai Li, Minna Hakkarainen
Central to the design and execution of nanocomposite strategies is the invention of polymer-affinitive and multifunctional nanoreinforcements amenable to economically viable processing. Here, a microwave-assisted approach enabled gram-scale fabrication of polymer-affinitive luminescent quantum dots (QDs) from spent coffee grounds. The ultrasmall dimensions (approaching 20 nm), coupled with richness of diverse oxygen functional groups, conferred the zero-dimensional QDs with proper exfoliation and uniform dispersion in poly(l-lactic acid) (PLLA) matrix...
August 10, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28763771/taurine-grafting-and-collagen-adsorption-on-plla-films-improve-human-primary-chondrocyte-adhesion-and-growth
#9
Luca Pellegrino, Rossana Cocchiola, Iolanda Francolini, Mariangela Lopreiato, Antonella Piozzi, Robertino Zanoni, Anna Scotto d'Abusco, Andrea Martinelli
Biocompatible and degradable poly(α-hydroxy acids) are one of the most widely used materials in scaffolds for tissue engineering. Nevertheless, they often need surface modification to improve interaction with cells. Aminolysis is a common method to increase the polymer hydrophilicity and to introduce surface functional groups, able to covalently link or absorb, through electrostatic interaction, bioactive molecules or macromolecules. For this purpose, multi-functional amines, such as diethylenediamine or hexamethylenediamine are used...
July 23, 2017: Colloids and Surfaces. B, Biointerfaces
https://www.readbyqxmd.com/read/28763610/bone-regeneration-by-means-of-a-three-dimensional-printed-scaffold-in-a-rat-cranial-defect
#10
Doo Yeon Kwon, Ji Hoon Park, So Hee Jang, Joon Yeong Park, Ju Woong Jang, Byoung Hyun Min, Wan-Doo Kim, Hai Bang Lee, Junhee Lee, Moon Suk Kim
Recently, computer-designed three-dimensional (3D) printing techniques have emerged as an active research area with almost unlimited possibilities. In this study, we used a computer-designed 3D scaffold to drive new bone formation in a bone defect. Poly-L-lactide (PLLA) and bioactive β-tricalcium phosphate (TCP) were simply mixed to prepare ink. PLLA+TCP showed good printability from the micronozzle and solidification within few seconds, indicating that it was indeed printable ink for layer-by-layer printing...
August 1, 2017: Journal of Tissue Engineering and Regenerative Medicine
https://www.readbyqxmd.com/read/28742224/synthesis-of-unimolecular-micelles-with-incorporated-hyperbranched-boltorn-h30-polyester-modified-with-hyperbranched-helical-poly-phenyl-isocyanide-chains-and-their-enantioselective-crystallization-performance
#11
Zhi-Huang Zhang, Chen-Yang Qiao, Jian Zhang, Wen-Ming Zhang, Jun Yin, Zong-Quan Wu
Here, the fabrication of unimolecular micelles functionalized with helical polymeric chains as a chiral nucleating agent in enantioselective crystallization is reported. Starting from a fractionated hyperbranched polyester (Boltorn H30), the ring-opening polymerization of l-lactic acid (LLA) and subsequent terminal-group modification affords the alkyne-Pd(II)-anchored hyperbranched macroinitiator (H30-PLLA-Pd). By taking advantage of a Pd(II)-catalyzed living polymerization of chiral pendant modified l- or d-phenyl isocyanide (PI) monomers, well-defined chiral unimolecular micelles (H30-PLLA-PPI) grafted with radiating helical PPI coronas of one predominant screw sense are obtained...
July 25, 2017: Macromolecular Rapid Communications
https://www.readbyqxmd.com/read/28722126/investigating-the-effect-of-poly-l-lactic-acid-nanoparticles-carrying-hypericin-on-the-flow-biased-diffusive-motion-of-hela-cell-organelles
#12
Rozhin Penjweini, Sarah Deville, Omid Haji Maghsoudi, Kristof Notelaers, Anitha Ethirajan, Marcel Ameloot
OBJECTIVES: In this study, we investigate in human cervical epithelial HeLa cells the intracellular dynamics and the mutual interaction with the organelles of the poly-l-lactic acid nanoparticles (PLLA NPs) carrying the naturally occurring hydrophobic photosensitizer hypericin. METHODS: Temporal and spatiotemporal image correlation spectroscopy was used for the assessment of the intracellular diffusion and directed motion of the nanocarriers by tracking the hypericin fluorescence...
July 19, 2017: Journal of Pharmacy and Pharmacology
https://www.readbyqxmd.com/read/28719857/in-situ-adjuvant-therapy-using-a-responsive-doxorubicin-loaded-fibrous-scaffold-after-tumor-resection
#13
Ziming Yuan, Wei Wu, Zhongwei Zhang, Zhiyong Sun, Ruoyu Cheng, Guoqin Pan, Xuemin Wang, Wenguo Cui
As tumor microenvironment becoming more and more important in tumor study, the acid pH around or in solid tumors drew lots of attentions. And the progress of drug delivery systems made the responsive-release possible. This time, we fabricated a new-type composite electrospun poly (L-lactide) (PLLA) fibrous scaffolds, that blent with the mesoporous silica particles (MSNs). Further more, we used sodium bicarbonate (SB) as acid sensitive agent which was wrapped inside the MSNs. And doxorubicin (DOX) was also wrapped into MSNs in order to achieve a sustained release to inhibit tumors in mice, which mimicked the remnant breast cancer with surgery...
July 1, 2017: Colloids and Surfaces. B, Biointerfaces
https://www.readbyqxmd.com/read/28701072/a-novel-biomimetic-composite-substitute-of-plla-gelatin-nanofiber-membrane-for-dura-repairing
#14
Kunxue Deng, Yaya Yang, Yiquan Ke, Chengyi Luo, Man Liu, Yuting Deng, Quan Tian, Yuyu Yuan, Tun Yuan, Tao Xu
OBJECTIVE: Biomimetic design will significantly improve growth and regeneration of dural cells and tissue for better repairing effects and fewer complications in repairing the native dura. This study designed a novel composite, biomimetic substitute based on the characteristics of native dura extracellular matrix. METHODS AND RESULTS: This substitute is expected to rapidly induce cell adhesion, migration, and fast regeneration of neotissue. The material characteristics (contact angle, surface charge, and zeta potential were evaluated), in vitro biological characteristics (cell stretch, connections between cells, cell proliferation) and in vivo tissue regeneration capability of this substitute were evaluated, compared to those of collagen dura substitute, the mostly used dura substitute...
July 12, 2017: Neurological Research
https://www.readbyqxmd.com/read/28685784/%C3%AE-pyridylenolate-zinc-catalysts-for-the-ring-opening-homo-and-copolymerization-of-%C3%AE%C2%B5-caprolactone-and-lactides
#15
Jianliang Bai, Xia Xiao, Yue Zhang, Jianbin Chao, Xia Chen
A family of zinc β-pyridylenolates with varying α,β-substituents has been synthesized. A direct reaction of β-pyridyl ketone ligands with ZnEt2 in toluene afforded dimeric [LZnEt]2 (L = (2-C5H4N)-C(R(1))[double bond, length as m-dash]C(R(2))-O-). X-ray structural data revealed that all the [LZnEt]2 complexes exist as μ-O-bridged dimers in the solid state, although they adopt a different geometry. Each of the [LZnEt]2 complexes is a highly active catalyst for the ring-opening polymerization (ROP) of ε-caprolactone (ε-CL) and racemic lactide (rac-LA), respectively...
August 14, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28672962/enhanced-regeneration-of-large-cortical-bone-defects-with-electrospun-nanofibrous-membranes-and-low-intensity-pulsed-ultrasound
#16
Leyi Huang, Youzhi Cai, Honghua Hu, Peng Guo, Zengfeng Xin
Poly-L-lactic acid (PLLA) nanofibrous membranes are widely utilized for tissue regeneration. Low intensity pulsed ultrasound (LIPUS) has been considered as a feasible modality for bone union. The aim of the present study was to investigate the potential synergistic effect of LIPUS and PLLA electrospun nanofibrous membranes on large cortical bone defects in rabbits in vivo. The bilateral rabbit tibia defect model was constructed using 18 adult NZ rabbits and the defect sites were treated with the nanofibrous membranes combined with LIPUS or nanofibrous membranes alone...
July 2017: Experimental and Therapeutic Medicine
https://www.readbyqxmd.com/read/28671263/small-cause-large-effect-structural-characterization-of-cutinases-from-thermobifida-cellulosilytica
#17
Doris Ribitsch, Altijana Hromic, Sabine Zitzenbacher, Barbara Zartl, Caroline Gamerith, Alessandro Pellis, Alois Jungbauer, Andrzej Łyskowski, Georg Steinkellner, Karl Gruber, Rupert Tscheliessnig, Enrique Herrero Acero, Georg M Guebitz
We have investigated the structures of two native cutinases from Thermobifida cellulosilytica, namely Thc_Cut1 and Thc_Cut2 as well as of two variants, Thc_Cut2_DM (Thc_Cut2_ Arg29Asn_Ala30Val) and Thc_Cut2_TM (Thc_Cut2_Arg19Ser_Arg29Asn_Ala30Val). The four enzymes showed different activities towards the aliphatic polyester poly(lactic acid) (PLLA). The crystal structures of the four enzymes were successfully solved and in combination with Small Angle X-Ray Scattering (SAXS) the structural features responsible for the selectivity difference were elucidated...
July 3, 2017: Biotechnology and Bioengineering
https://www.readbyqxmd.com/read/28666885/sandwich-type-plla-nanosheets-loaded-with-bmp-2-induce-bone-regeneration-in-critical-sized-mouse-calvarial-defects
#18
Kuo-Chin Huang, Fumiko Yano, Yasutaka Murahashi, Shuta Takano, Yoshiaki Kitaura, Song Ho Chang, Kazuhito Soma, Steve W N Ueng, Sakae Tanaka, Kazuhiko Ishihara, Yosuke Okamura, Toru Moro, Taku Saito
To overcome serious clinical problems caused by large bone defects, various approaches to bone regeneration have been researched, including tissue engineering, biomaterials, stem cells and drug screening. Previously, we developed a free-standing biodegradable polymer nanosheet composed of poly(L-lactic acid) (PLLA) using a simple fabrication process consisting of spin-coating and peeling techniques. Here, we loaded recombinant human bone morphogenetic protein-2 (rhBMP-2) between two 60-nm-thick PLLA nanosheets, and investigated these sandwich-type nanosheets in bone regeneration applications...
September 1, 2017: Acta Biomaterialia
https://www.readbyqxmd.com/read/28657452/tuning-of-the-surface-biological-behavior-of-poly-l-lactide-based-composites-by-the-incorporation-of-polyelectrolyte-complexes-for-bone-regeneration
#19
Xuehong Wang, Jie Wei, Jianding Chen, Songchao Tang
Poly(L-lactide)(PLLA)-based composites have been widely used for tissue regeneration. Novel polyelectrolyte complexes (PECs) consisted of carboxymethyl starch sodium (CMS) and chitosan oligosaccharide (COS) was fabricated and evaluated. The results suggested that the CMS/COS-PECs (CC-PECs) distinguished from the original polymers alone, presenting an amorphous structure. Then, the CC-PECs/PLLA composites were prepared by varying the relative amount of CC-PECs in the PLLA-matrix, demonstrated by means of the surface morphology, hydrophilicity, water uptake, in vitro degradability and primary cell responses...
July 6, 2017: Journal of Biomaterials Science. Polymer Edition
https://www.readbyqxmd.com/read/28653337/hardystonite-coated-poly-l-lactide-nanofibrous-scaffold-and-efficient-osteogenic-differentiation-of-adipose-derived-mesenchymal-stem-cells
#20
Banafsheh Tavangar, Shaghayegh Arasteh, Haleh Edalatkhah, Ali Salimi, Ali Doostmohammadi, Ehsan Seyedjafari
In this study, a ceramic-coated nanofibrous scaffold has been fabricated to biomimic the microstructure of natural extracellular matrix and the stiffening inorganic compartment of bone. Poly-l-lactic acid (PLLA) nanofibers were electrospun and exposed to oxygen plasma to induce hydrophilicity and promote ceramic adsorption. Hardystonite (HS), which possesses superior osteoinduction potential over hydroxyapatite, was coated on plasma-treated PLLA nanofibers by drenching the nanofibers in HS suspension. Pure and composite PLLA-based scaffolds were characterized in terms of physical and biological properties...
June 27, 2017: Artificial Organs
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