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From Conventional Approaches to Sol-gel Chemistry and Strategies for the Design of 3D Additive Manufactured Scaffolds for Craniofacial Tissue Engineering
Published in Vincenzo Guarino, Marco Antonio Alvarez-Pérez, Current Advances in Oral and Craniofacial Tissue Engineering, 2020
A. Gloria, T. Russo, M. Martorelli, De Santis R.
Regarding synthetic polymers, polylactic acid (PLA), polyglycolide (PGA), poly(lactide-co-glycolide) (PLGA), poly(E-caprolactone) (PCL), polyhydroxyalkanoates (PHAs) and (propylene fumarate) (PPF). Such polymers have been developed to tailor the mechanical properties of the scaffolds by varying the degrees of cross-linking and concentration or by means of copolymerization strategies (Thrivikraman et al. 2017).
Packaging and Shelf-Life Evaluation of Shoots
Published in Nirmala Chongtham, Madho Singh Bisht, Bamboo Shoot, 2020
Nirmala Chongtham, Madho Singh Bisht
Some of the packaging materials mainly plastic-based are non-degradable, non-reusable and non-recyclable which augment environmental waste and there is also an issue of mobilization of low molecular weight constituents like stabilizers, plasticizers, monomers and oligomers from the packaging material to the food product. The use of biopolymers for packaging can overcome these drawbacks, like polyesters, which could either directly be extracted from proteins, lipids and polysaccharides or can be synthesized by polymerization e.g. aliphatic-aromatic copolymers, aliphatic polyesters, polylactic aliphatic copolymers. Bio-based polymers that are renewable like poly lactic acid, oil-based monomers such as polycaprolactone, micro-organisms generated material like polyhydroxyalkanoates can be used to prepare packaging material and thereafter their application on bamboo shoots can be studied. Application of nanocomposites has also been introduced for food packaging but there is limited scientific data on their toxicological effect on humans or migration of nanoparticles to food, which must further be explored.
Polymeric Colloidal Carriers for Natural Polyphenolic Compounds
Published in Madhu Gupta, Durgesh Nandini Chauhan, Vikas Sharma, Nagendra Singh Chauhan, Novel Drug Delivery Systems for Phytoconstituents, 2020
Maria Rosaria Lauro, Teresa Musumeci, Francesca Sansone, Giovanni Puglisi, Rosario Pignatello
In recent years, different authors have developed colloidal carriers to protect and control the release of polyphenols using aliphatic polyesters, which can be of microbial origin or obtained by chemical synthesis. They include poly-lactide (PLA), poly (lactide-co-glycolide) (PLGA), poly-ε-caprolactone (PCL), polyhydroxyalkanoates (PHAs), and their copolymers and derivatives. Due to their controlled delivery properties, biodegradability, and biocompatibility, their application is of great interest to the biomedical field. These polymers show ideal features for encapsulating lipophilic compounds. Biodegradable polyesters can be classified with regard to the mode of bonding of the constituent monomers: (i) poly (hydroxy acid)s with –O–R–CO– as repeating monomeric units, such as poly (3-hydroxybutyrate) [P (3HB)], PLA, poly (glycolic acid) (PGA), PCL, etc.; and (ii) poly (alkylenedicarboxylate)s, i.e., poly (ethylene succinate) (PESu), poly (butylene succinate) (PBSu), poly (ethylene adipate) (PEA), and poly (butylene adipate) (PBA). Biodegradable polyesters can be further split into two groups: (i) biomass-based polyesters (microbial origin), such as PLA, P (3HB), and their copolymers, and (ii) petroleum-based aliphatic polyesters such as PGA, PCL, PBA, poly (3-hydro propionate) (PHP), and PBSu. Synthetic polymers offer the advantage of higher purity and reproducibility with respect to natural polymers. Conversely, polyesters from microbial origin can be produced from renewable raw materials, thus playing a potential role in environmentally-friendly industry and green chemistry strategies (Chanprateep, 2010).
Nanomaterials in tuberculosis DNA vaccine delivery: historical perspective and current landscape
Published in Drug Delivery, 2022
Xing Luo, Xiaoqiang Zeng, Li Gong, Yan Ye, Cun Sun, Ting Chen, Zelong Zhang, Yikun Tao, Hao Zeng, Quanming Zou, Yun Yang, Jieping Li, Hongwu Sun
Polyhydroxy biopolyester nanoparticles include poly (3-hydroxybutyrate) (PHB) and polyhydroxyalkanoates (PHA); PHB is commonly extracted and purified from E. coli and Lactococcus lactis. Antigens carried on specific nanoparticles are preferentially recognized and presented, enhancing the ability of cells to respond to immunogens (Khader et al., 2007). TB DNA vaccines containing PHB nanoparticles with ESAT-6 or Ag85A (the dominant antigens of M. tuberculosis) on the surface of biological beads induce high levels of cytokines interleukin (IL)-2, IFN-γ, tumor necrosis factor (TNF)-α, IL-17A, and IL-6 on intramuscular injection. According to Parlane et al., these bovine-TB vaccines cause a high T-cell immune response, with both CD4+ and CD8+ involved in the induction of IFN-γ release (Parlane et al., 2014). In TB DNA vaccines, PHA nanoparticles have been produced using bacteria (via bioengineering) as intracellular contents when carbon sources are abundant (Grage et al., 2009).
Synthetic biodegradable polyesters for implantable controlled-release devices
Published in Expert Opinion on Drug Delivery, 2022
Jinal U. Pothupitiya, Christy Zheng, W. Mark Saltzman
Polymer degradation in implants occurs through a combination of events that include hydrolysis, oxidation, enzymatic degradation, and physical degradation. For most polyesters, physical changes to the matrix occur due to the penetration of water, which can cause matrix swelling. Water penetration induces hydrolysis of the polyester backbones, leading to polymer degradation and drug release. The pH of the implant environment influences the rate of polymer degradation and therefore the drug release profile. In general, strongly acidic and alkaline environments enhance the degradation process of polyesters [79,102]. For most aliphatic polyesters, such as PLA, PCL, and polyhydroxyalkanoates (PHA), polymer degradation can also be influenced by enzymatic hydrolysis by esterases [103]. The extent of enzymatic activity on the polyesters greatly depends on substrate specificity [104,105], flexibility of polymer chains [106], and hydrophilicity of the aliphatic polymer [107,108]. Additionally, polymer inherent properties such as pH sensitivity, molecular weight, polymer architecture, crystallinity, and hydrophilicity influence polymer degradation significantly [2], often by controlling the spatial or temporal pattern of water uptake.
Understanding the basis of medical use of poly-lactide-based resorbable polymers and composites – a review of the clinical and metabolic impact
Published in Drug Metabolism Reviews, 2019
Sergiu Vacaras, Mihaela Baciut, Ondine Lucaciu, Cristian Dinu, Grigore Baciut, Liana Crisan, Mihaela Hedesiu, Bogdan Crisan, Florin Onisor, Gabriel Armencea, Ileana Mitre, Ioan Barbur, Winfried Kretschmer, Simion Bran
Other biodegradable polyesters in use are:PHA – polyhydroxyalkanoatesPHH – polyydroxyhexanoatesPHB – polyhydroxybutyratePHV – polyhydroxyvaleratePCL – polycaprolactonePBS – polybutylene succinatePBSA – polybutylene succinate adipateAAC – aliphatic–aromatic copolyestersPET – polyethylene terephthalatePBAT – polybutylene adipate/terephthalatePTMAT – polymethylene adipate/terephthalate (Nampoothiri et al. 2010)