Poly(hydroxy alkanoate)s in Medical Applications

Luef, Klaus Peter; Stelzer, Franz; Wiesbrock, Frank

doi:10.15255/cabeq.2014.2261

Cited by 66 publications

(32 citation statements)

References 90 publications

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“…All polymers produced demonstrated initial thermal degradation above 283 °C, with emphasis on the PHA synthetized by C. necator IPT 026, which exhibited the best thermal stability with an initial degradation temperature of 311.86 °C, a maximum decomposition temperature of 334.42 °C and a total weight loss of 99.35 %. Similarly to what was found for the last strain, Ribeiro et al 52 reported a PHA with initial degradation temperature of 316.7 °C in the bioconversion (Burkholderia cepacia IPT 438) of glycerol, and Campos et al 25 described a T onset of 306.8 °C for PHA produced by C. necator IPT 026 in consumption of crude glycerol.…”

Section: Biopolymers Characterizationsupporting

confidence: 58%

Impact of Different Bacterial Strains on the Production, Composition, and Properties of Novel Polyhydroxyalkanoates Using Crude Palm Oil as Substrate

Rodrigues¹

2018

Chem.Biochem.Eng.Q.

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Polyhydroxyalkanoates (PHAs) are a group of biodegradable polymers produced from renewable sources by prokaryotic biocatalysts, accumulated intracellularly for energy and carbon storage. In the present study, production and characterization of PHAs synthetized by Cupriavidus necator (IPT 026 and IPT 027) and Burkholderia cepacia (IPT 119 and IPT 400) were evaluated using crude palm oil (C 16:0 = 26.44 %, C 18:1 = 54.50 %, C 18:2 = 13.41 %) as substrate (15 g L-1 crude palm oil, pH 7.0, 180 rpm, 72 h). All strains were able to synthesize novel PHA copolymers (0.10-1.45 g L-1), and IPT 027 displayed the highest production. Copolymers monomeric composition (M w = 173.78-389.30 kDa) was comprised mostly of hydroxyhexadecanoate (41.43-53.15 %) and hydroxy-9-octadecenoate (14.91-29.61 %). PHAs were predominantly amorphous, showed low polydispersity, and good thermal stability (T onset ≥ 283 °C), which increased proportionally to crystallinity. Crude palm oil constitutes an emerging alternative for PHAs production, and microorganism strains strongly affect polymer accumulation, monomeric composition, molar mass, and properties.

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Section: Biopolymers Characterizationsupporting

confidence: 58%

Impact of Different Bacterial Strains on the Production, Composition, and Properties of Novel Polyhydroxyalkanoates Using Crude Palm Oil as Substrate

Rodrigues¹

2018

Chem.Biochem.Eng.Q.

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“…There has been an increasing interest in the use of natural materials as drug delivery vehicles due to their appealing properties. The natural origin, biodegradability, and biocompatibility of PHAs make them suitable for a variety of applications in the health industry [10,25,26]. Particularly because of their property of biodegradation, PHAs were studied as a matrix for the antibiotic and as a controlled drug delivery system.…”

Section: Resultsmentioning

confidence: 99%

“…Furthermore, the by-products of their hydrolytic degradation make it possible to obtain common blood constituents (a ketone body produced by the liver from fatty acids, ketogenesis) [8]. Pas have performed well in a number drug delivery applications due to their excellent biocompatibility, non-toxicity and biodegradability [3,9,10,11,12,13]. Metal-based drug eluting systems have received little attention in the literature in comparison to polymer-based systems.…”

Section: Introductionmentioning

confidence: 99%

Antibacterial PHAs coating for titanium implants

Rodríguez-Contreras

García

Manero

et al. 2017

European Polymer Journal

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Biomaterial-associated infection is a serious complication of modern implantation surgery.Thus, the improvement of implant surfaces is required to avoid the first stage for biofilm formation, bacterial adhesion. The current research addresses this issue by developing drug delivery systems (DDS) consisting of antibiotic-loaded polyhydroxyalkanoates (PHAs) coatings on titanium implants. Dip-coating technique was used to achieve optimal coatings with biodegradable biopolyesters, polyhydroxybutyrate (PHB) and its copolymer, polyhydroxybutyrate-co-hydroxyvalerate (PHBV). The coatings were completely characterized (wettability, topography, thickness and roughness), and studies of drug delivery, toxicity, antibacterial effect, and cell adhesion were performed. For both of biopolymers, surfaces were partially covered with 1 and 3 immersions, while with 6, they were completely covered. Although both antibiotic-loaded biopolymer coatings assure the protection against bacteria populations, PHBV coatings are closer to the desired release profile; its faster degradation provides for a greater and more stable drug release for a given period of time compared to PHB coatings. The use of coatings with different drug concentration per layer results in more controlled and homogeneous releases. The DDS designed not only assure toavoid the first stage of bacterial adhesion, but also their proliferation and biofilm formation, since the coatings degrade with time under physiological conditions, guaranteeing a prolonged drug release.

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“…PHAs are a class of naturally occurring polyesters of various hydroxycarboxylic acids, which are produced and accumulated by many organisms in the form of intracellular granules to store carbon and energy when they are subjected to conditions of lack of nutrients [11]. Two main types of PHAs are generally distinguished, namely short-chain length PHAs (scl-PHAs), consisting of 4-5 carbon atoms per repetition unit, and medium-chain length PHAs (mcl-PHAs), with 6-14 carbon atoms per repetition unit [12]. Compared to the most extensively investigated biodegradable and biocompatible polyesters such as polylactic acid (PLA) [13], polyglycolic acid (PGA) [14], poly(caprolactone) (PCL) [15] and poly(lactic-co-glycolic) (PLGA) [16], PHAs are superior for the following reasons.…”

Section: Overviewmentioning

confidence: 99%

Enabling electrospinning of medium-chain length polyhydroxyalkanoates (PHAs) by blending with short-chain length PHAs

Çiçek

Liu

2018

International Journal of Polymeric Materials and Polymeric Biom

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Bacterial infection is a serious issue in wound healing. Extensive use of biocides in wound dressings have raised concerns like biocide resistance and unwanted harm to normal skin cells. In this thesis, I report a new approach to realize bacteria-triggered release of biocide to the sites of bacterial infections from core-shell polyhydroxyalkanoate (PHA)-based nanofibers prepared by coaxial electrospinning. The hydrophobic PHA-based shell can effectively prevent the biocide from undesirable payload release in physiological environments without pathogens. However, in the presence of pathogens, the PHA-based shell is degraded by pathogens, and the encapsulated biocide is released. The released biocide subsequently can impose targeted antimicrobial effects on the bacteria. Using Pseudomonas aeruginosa as a model bacterium and dodecyltrimethylammonium chloride as a model biocide, we demonstrated that the core-shell PHA-based nanofibers released encapsulated dodecyltrimethylammonium chloride in the presence of Pseudomonas aeruginosa, resulting in targeted inhibition of Pseudomonas aeruginosa growth. iii Acknowledgement Undertaking this master degree has been a challenging experience for me and I could not make it without the support and help received from many people. I would like to express my gratitude to my supervisor, Dr. Song Liu, for his support, guidance, and help during my M.Sc. program. I appreciate his vast knowledge, ideas, and encouragement to make my research experience motivational, productive, and enjoyable. It has been a great honour to work and learn from him. Thanks to his efforts, I have grown tremendously in both my academic and personal life. A special thanks goes to my co-advisor, Dr. Nazim Cicek, without whose financial support and encouragement I may not fully focus on my research program during my two-year M.Sc. program. I must also thank Dr. David B. Levin for all the guidance and assistance throughout my graduate studies. It has been such a valuable experience for me to cooperate with different students in Dr. Levin's group. I am also greatly thankful to Dr. Sarvesh Logsetty for his valuable comments in my committee meetings. I also want to thank all my friends who helped me get through my M.Sc. program. Some friends, like Seungil Kim and Dr. Hardev Singh, were kind and tolerant enough to teach me chemistry laboratory technique and professionalism. Sadegh Ghanbar, Zahra Abdali, Mohammad Reza Kazemian, Jie Li, and Lucy Wang, were good enough not to throw me overboard while at sea. And I would like to send my thanks out to Dr. Levin's PhD students Christopher Dartiailh and Warren Blunt, for their help in all aspects of our collaboration. I thank with love to my wife, Xing Xie, for her continuous support, understanding, and encouragement. She has made countless sacrifices to help me get to this point. This thesis has been written during my stay at the Department of Biosystems Engineering of the University of Manitoba. I would like to thank the University of Manitoba Faculty of Graduate Studies f...

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Poly(hydroxy alkanoate)s in Medical Applications

Cited by 66 publications

References 90 publications

Impact of Different Bacterial Strains on the Production, Composition, and Properties of Novel Polyhydroxyalkanoates Using Crude Palm Oil as Substrate

Impact of Different Bacterial Strains on the Production, Composition, and Properties of Novel Polyhydroxyalkanoates Using Crude Palm Oil as Substrate

Antibacterial PHAs coating for titanium implants

Enabling electrospinning of medium-chain length polyhydroxyalkanoates (PHAs) by blending with short-chain length PHAs

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