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Poly-l-lactic acid

Jacob Barlow, Kevin Gozzi, Chase P Kelley, Benjamin M Geilich, Thomas J Webster, Yunrong Chai, Srinivas Sridhar, Anne L van de Ven
Encapsulating bacteria within constrained microenvironments can promote the manifestation of specialized behaviors. Using double-emulsion droplet-generating microfluidic synthesis, live Bacillus subtilis bacteria were encapsulated in a semi-permeable membrane composed of poly(ethylene glycol)-b-poly(D,L-lactic acid) (mPEG-PDLLA). This polymer membrane was sufficiently permeable to permit exponential bacterial growth, metabolite-induced gene expression, and rapid biofilm growth. The biodegradable microparticles retained structural integrity for several days and could be successfully degraded with time or sustained bacterial activity...
October 15, 2016: Applied Microbiology and Biotechnology
Neda Khameh Khorshid, Kaizheng Zhu, Kenneth D Knudsen, Sara Bekhradnia, Sverre Arne Sande, Bo Nyström
The thermoresponsive amphiphilic block copolymer poly(d,l-lactic acid-co-glycolic acid)-block-poly(ethylene glycol)-block-poly(d,l-lactic acid-co-glycolic acid) (PLGA-PEGn -PLGA), which exhibits a reversible temperature-induced sol-gel transition at higher polymer concentrations in aqueous solution has attached a great deal of interest because of its potential in biomedical applications. In the present work, the length of the hydrophobic PLGA blocks is kept constant, whereas the length of the hydrophilic PEG block is altered and this variation has a pronounced impact on the phase behavior of the aqueous samples and the structure of the polymer...
October 14, 2016: Macromolecular Bioscience
Tianyuan Ci, Yuning Shen, Shuquan Cui, Ruili Liu, Lin Yu, Jiandong Ding
Inadequate drug loading of hydrophobic drugs is a classic problem when hydrogels are utilized as sustained-release carriers of drugs. Herein, a strategy to load plenty of hydrophobic drugs is presented. The antitumor drug 10-hydroxycamptothecin in the thermogel of poly(d,l-lactic acid-co-glycolic acid)-b-poly(ethylene glycol)-b-poly(d,l-lactic acid-co-glycolic acid) is employed. The drug is soluble in an alkaline medium, yet insoluble in a neutral/acidic medium. The crystallization is triggered after adding an alkaline drug solution into an acidic copolymer solution...
October 14, 2016: Macromolecular Bioscience
Serban San-Marina, Ayushman Sharma, Stephen G Voss, Jeffrey R Janus, Grant S Hamilton
Importance: Nasal reconstruction in patients who are missing a significant amount of structural nasal support remains a difficult challenge. One challenge is the deficiency of cartilage left within the nose as a consequence of rhinectomy or a midline destructive disease. Historically, the standard donor source for large quantities of native cartilage has been costal cartilage. Objective: To enable the development of protocols for new mesenchymal stem cell technologies as alternative procedures with reduced donor site morbidity, risk of infection and extrusion...
October 13, 2016: JAMA Facial Plastic Surgery
Xin Wang, Alexandros Lamprou, Frantisek Svec, Yu Bai, Huwei Liu
A new approach to the preparation of enantioselective porous polymer monolithic columns with incorporated chiral metal-organic framework for nano-liquid chromatography has been developed. While no enantioseparation was achieved with monolithic poly(4-vinylpyridine-co-ethylene dimethacrylate) column, excellent separations of both enantiomers of (±)-methyl phenyl sulfoxide were achieved with its counterpart prepared after admixing the metal-organic framework [Zn2 (benzene dicarboxylate)(l-lactic acid)(dmf)](DMF), which is synthesized from zinc nitrate, l-lactic acid, and benzene dicarboxylic acid in the polymerization mixture...
October 12, 2016: Journal of Separation Science
Sisi Zheng, Li Luo, Ruonan Bo, Zhenguang Liu, Jie Xing, Yale Niu, Yuanliang Hu, Jiaguo Liu, Deyun Wang
This study aimed to optimize the preparation conditions of pachyman (PHY)-loaded poly(d,l-lactic acid) (PLA) (PHYP) nanospheres by response surface methodology, explore their characteristics, and assess their effects on splenic lymphocytes. Double emulsion solvent evaporation was used to synthesize PHYP nanospheres, and the optimal preparation conditions were identified as a concentration of poloxamer 188 (F68) (w/v) of 0.33%, a concentration of PLA of 30 mg/mL, and a ratio of PLA to drug (w/w) of 10.25:1 required to reach the highest encapsulation efficiency, which was calculated to be 59...
2016: International Journal of Nanomedicine
Yuji Yamazaki, Naoki Watabe, Hiroaki Obata, Eri Hara, Masashi Ohmae, Shunsaku Kimura
Molecular assemblies varying morphologies in a wide range from spherical micelle, nanosheet, curved sheet, nanotube and vesicle were prepared and loaded with Lewis y (Le(y) ) tumor-associated carbohydrate antigen on the assembly surface. The molecular assemblies were composed of poly(sarcosine)m -block-poly(L-lactic acid)30 (m = 15 or 50, Lactosome), poly(sarcosine)m -block-(D/L-Leu-Aib)n (m = 22 or 30, n = 6 or 8) and their combinations. The molecular assemblies carrying Le(y) on the surface were administered in BALB/c nu/nu mice...
October 10, 2016: Journal of Peptide Science: An Official Publication of the European Peptide Society
Akshit Peer, Rabin Dhakal, Rana Biswas, Jaeyoun Kim
We compare the rates of drug release from nanopatterned and flat biodegradable polymer surfaces, and observe significantly lower release rates from the nanopatterned surfaces. Specifically, we nanopattern poly(l-lactic acid) (PLLA), a biodegradable polymer frequently used for fabricating drug-eluting coronary stents, through microtransfer molding and solvent casting and investigate the nanopattern's impact on the release of sirolimus, an immunosuppressant agent, coated on the PLLA surface using high performance liquid chromatography/mass spectrometry...
October 5, 2016: Nanoscale
Huihua Yuan, Jinbao Qin, Jing Xie, Biyun Li, Zhepao Yu, Zhiyou Peng, Bingcheng Yi, Xiangxin Lou, Xinwu Lu, Yanzhong Zhang
This study was designed to assess the efficacy of hyaluronan (HA) functionalized well-aligned nanofibers of poly-l-lactic acid (PLLA) in modulating the phenotypic expression of vascular smooth muscle cells (vSMCs) for blood vessel regeneration. Highly aligned HA/PLLA nanofibers in core-shell structure were prepared using a novel stable jet electrospinning approach. Formation of a thin HA-coating layer atop each PLLA nanofiber surface endowed the uni-directionally oriented fibrous mats with increased anisotropic wettability and mechanical compliance...
September 15, 2016: Nanoscale
Douglas R Marques, Luís A L Dos Santos, Marie A O'Brien, Sarah H Cartmell, Julie E Gough
The polymeric blend of poly (lactic-co-glycolic acid) (PLGA) and polyisoprene (PI) has recently been explored for application as stents for tracheal stenosis and spring for the treatment of craniosynostosis. From the positive results presented in other biomedical applications comes the possibility of investigating the application of this material as scaffold for tissue engineering (TE), acquiring a deeper knowledge about the polymeric blend by exploring a new processing technique while attending to the most fundamental demands of TE scaffolds...
October 6, 2016: Journal of Biomedical Materials Research. Part B, Applied Biomaterials
Christopher D L Johnson, Anthony R D'Amato, Ryan J Gilbert
There is currently no cure for individuals with spinal cord injury (SCI). While many promising approaches are being tested in clinical trials, the complexity of SCI limits several of these approaches from aiding complete functional recovery. Several different categories of biomaterials are investigated for their ability to guide axonal regeneration, to deliver proteins or small molecules locally, or to improve the viability of transplanted stem cells. The purpose of this study is to provide a brief overview of SCI, present the different categories of biomaterial scaffolds that direct and guide axonal regeneration, and then focus specifically on electrospun fiber guidance scaffolds...
2016: Cells, Tissues, Organs
Ezequiel Ernesto Zaidenberg, Pablo Roitman, Gerardo Luis Gallucci, Jorge Guillermo Boretto, Pablo De Carli
Background: In recent years the use of biodegradable suture anchors for treating tendon and ligament pathology in hand surgery became popular. These materials are biocompatible, radiolucent, and load sharing, as they incrementally transfer load to surrounding bone during the resorption process. Despite these numerous advantages, polyglycolic (PGA) and poly-L-lactic acid (PLLA) have become a problem because of the potential risk for foreign body reactions. Methods: This article presents a case of an intraosseous foreign body reaction and massive osteolysis of the proximal carpal after dorsal lunate dislocation repair with bioabsorbable suture anchors...
September 2016: Hand: Official Journal of the American Association for Hand Surgery
Yanping Cheng, Pawel Gasior, Masahiko Shibuya, Kamal Ramzipoor, Chang Lee, Edward A Estrada, Daniell Dokko, Jenn C McGregor, Gerard B Conditt, Greg L Kaluza, Juan F Granada
BACKGROUND: Clinically available bioresorbable scaffolds (BRS) rely on polymer crystallinity to achieve mechanical strength resulting in limited overexpansion capabilities and structural integrity when exposed to high-loading conditions. We aimed to evaluate the biomechanical behavior and vascular healing profile of a novel, sirolimus-eluting, high-molecular-weight, amorphous poly-l-lactic acid-based BRS (Amaranth BRS). METHODS AND RESULTS: In vitro biomechanical testing was performed under static and cyclic conditions...
October 2016: Circulation. Cardiovascular Interventions
Tadahisa Sugiura, Shuhei Tara, Hidetaka Nakayama, Tai Yi, Yong-Ung Lee, Toshihiro Shoji, Christopher K Breuer, Toshiharu Shinoka
OBJECTIVE: Bioresorbable vascular grafts are biologically active grafts that are entirely reconstituted by host-derived cells through an inflammation-mediated degradation process. Calcification is a detrimental condition that can severely affect graft performance. Therefore, prevention of calcification is of great importance to the success of bioresorbable arterial vascular grafts. The objective of this study was to test whether fast-degrading (FD) bioresorbable arterial grafts with high cellular infiltration will inhibit calcification of grafts...
September 26, 2016: Journal of Vascular Surgery
Hsin-I Hung, Oliver J Klein, Sam W Peterson, Sarah R Rokosh, Sam Osseiran, Nicholas H Nowell, Conor L Evans
Photodynamic therapy regimens, which use light-activated molecules known as photosensitizers, are highly selective against many malignancies and can bypass certain challenging therapeutic resistance mechanisms. Photosensitizers such as the small cationic molecule EtNBS (5-ethylamino-9-diethyl-aminobenzo[a]phenothiazinium chloride) have proven potent against cancer cells that reside within acidic and hypoxic tumour microenvironments. At higher doses, however, these photosensitizers induce "dark toxicity" through light-independent mechanisms...
September 30, 2016: Scientific Reports
Andrea G Galuppo, Pedro C Chagastelles, Douglas Gamba, Daikelly B Iglesias, Laura Sperling, Janine Machado, Joachim Wendorff, Cesar L Petzhold, Patricia Pranke
The aim of the study has been to evaluate the morphology, proliferation and pluripotency maintenance of mouse embryonic stem cells (mESCs) cultivated on poly(lactic-co-glycolic acid) scaffolds. The scaffolds were hydrolyzed with NaOH (treated) and non-hydrolyzed (untreated). Morphological and mechanical characterization of the scaffolds was performed. mESC were evaluated for cell viability, cytotoxicity, expression of pluripotency markers, colony morphology and overall distribution. The treatment generated a reduction in the hydrophobic characteristics of the scaffolds, leading to a higher wettability compared to the untreated group...
September 29, 2016: Journal of Biomedical Materials Research. Part A
Adam E Jakus, Alexandra L Rutz, Sumanas W Jordan, Abhishek Kannan, Sean M Mitchell, Chawon Yun, Katie D Koube, Sung C Yoo, Herbert E Whiteley, Claus-Peter Richter, Robert D Galiano, Wellington K Hsu, Stuart R Stock, Erin L Hsu, Ramille N Shah
Despite substantial attention given to the development of osteoregenerative biomaterials, severe deficiencies remain in current products. These limitations include an inability to adequately, rapidly, and reproducibly regenerate new bone; high costs and limited manufacturing capacity; and lack of surgical ease of handling. To address these shortcomings, we generated a new, synthetic osteoregenerative biomaterial, hyperelastic "bone" (HB). HB, which is composed of 90 weight % (wt %) hydroxyapatite and 10 wt % polycaprolactone or poly(lactic-co-glycolic acid), could be rapidly three-dimensionally (3D) printed (up to 275 cm(3)/hour) from room temperature extruded liquid inks...
September 28, 2016: Science Translational Medicine
Rohit Bisht, Ilva D Rupenthal
Frequent intravitreal injections are currently used to overcome the ocular barriers and provide sufficient drug to the posterior eye segment. However, intravitreal injections have been associated with a number of complications and high treatment costs. To overcome these limitations, peptide-loaded poly(d,l-lactic-co-glycolic acid) nanoparticles (PLGA NPs) were developed using the nanoprecipitation technique and were optimized via Box-Behnken Design (BBD) and Response Surface Methodology (RSM). Developed NPs were evaluated for potential toxicity and cell apoptosis using the zebrafish embryo toxicity (ZET) model with titanium dioxide NPs and ethanol (1% v/v) serving as positive controls...
September 27, 2016: Pharmaceutical Development and Technology
N R Ravikumara, Mausumi Bharadwaj, Basavaraj Madhusudhan
The optimization of tamoxifen citrate entrapment and its release from biodegradable poly(d,l) lactic acid nanoparticles are prepared by modified spontaneous emulsification solvent diffusion method. Since the addition of tamoxifen citrate induces the formation of drug crystals from nanoparticle suspension the influence of several parameters on tamoxifen citrate encapsulation was investigated. In vitro studies for cytotoxicity, DNA ladder, and the expression of Bcl-2-Bax expression were also investigated for MCF-7 and MDA-MB-231 cells after the addition of tamoxifen citrate alone and tamoxifen citrate-poly(d,l) lactic acid-nanoparticles (encapsulated tamoxifen citrate)...
September 22, 2016: Journal of Biomaterials Applications
Xun Jin, Bingwen Zou, Li Luo, Chuanhong Zhong, Peilan Zhang, Hao Cheng, Yanfang Guo, Maling Gou
Cancer chemotherapy can benefit from the combination of different anticancer drugs. Here, we prepared doxorubicin (Dox)- and thioridazine (Thio)-coloaded methoxy poly(ethylene glycol)-poly(l-lactic acid) (MPEG-PLA) nanoparticles (NPs) for breast cancer therapy. These NPs have an average particle size of 27 nm. The drug loading efficiencies of Thio and Dox are 4.71% and 1.98%, respectively. Compared to the treatment of Thio or Dox alone, the combination of Thio and Dox exhibited a synergistic effect in inhibiting the growth of 4T1 breast cancer cells in vitro...
2016: International Journal of Nanomedicine
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