Structural and Morphological Features of Synthetic and Natural Polymers

1991 ◽  
Vol 255 ◽  
Author(s):  
Bernard Lotz
Keyword(s):  
Crystal Structures ◽  
Synthetic Polymers ◽  
Morphological Features ◽  
Natural Polymers ◽  
Two Systems ◽  
Synthetic And Natural Polymers ◽  
Cross Fertilization ◽  
Natural And Synthetic

AbstractThe crystal structures and crystalline morphologies of natural and synthetic polymers are briefly reviewed. Analogies and differences between these two systems are presented. Several examples of cross-fertilization of research in the two fields are presented, with emphasis, among natural polymers, on fibrous polypeptides and proteins.

Chitosan Based Nanoparticles in Drug Delivery

2009 ◽  
Vol 2 (2) ◽  
pp. 517-522 ◽  
Author(s):  
J. K. Patel ◽  
N. P. Jivani
Keyword(s):  
Drug Delivery ◽  
Drug Delivery Systems ◽  
Chitosan Nanoparticles ◽  
Synthetic Polymers ◽  
Delivery Systems ◽  
Natural Polymers ◽  
Different Characteristics ◽  
Hydrophilicity And Hydrophobicity ◽  
Nanoparticulate Systems ◽  
Natural And Synthetic

Nanoparticles have gained considerable attention in recent years as one of the most promising drug delivery systems owing to their unique potentials via combining the different characteristics of hydrophilicity and hydrophobicity with a nanoparticle (e.g., very small size). Several polymeric nanoparticulate systems have been prepared and characterized in recent years, based on both natural and synthetic polymers, each with its own advantages and drawbacks. Among the natural polymers, chitosan has been studied extensively for preparation of nanoparticles.  Chitosan nanoparticles have been reported with different characteristics with respect to drug delivery. This review presents various types of chitosan based nanoparticles in drug delivery.

scholarly journals Biodegradable polymers, current trends of research and their applications, a review

2020 ◽  
pp. 18-18
Author(s):  
Maja Colnik ◽  
Masa Knez-Hrncic ◽  
Mojca Skerget ◽  
Zeljko Knez
Keyword(s):  
Tissue Engineering ◽  
Biodegradable Polymers ◽  
Oil Prices ◽  
Synthetic Polymers ◽  
Hazardous Substances ◽  
Waste Plastics ◽  
Natural Polymers ◽  
Current Trends ◽  
Petroleum Resources ◽  
Synthetic And Natural Polymers

Biodegradable polymers have been developed rapidly in the last years and are widely used today in the fields of pharmacy, clinical biomedicine, cosmetic, medical, packing industries, tissue engineering, agriculture and other areas. The interest in biodegradable polymers has been increasing, mainly due to rising oil prices, which is the basic feedstock of plastic derived from petroleum, and also due to the problem of the removal of waste plastics that accumulate in the environment. Biodegradable polymers have many advantages in contrast to synthetic polymers and can be decomposed in the environment to non-hazardous substances. Biodegradable polymers are classified into two classes based on their synthesis i.e., synthetic and natural polymers. They are derived either from petroleum resources or from biological resources. The following review presents an overview of the different biodegradable polymers and their properties, current scientific research, applications, global production of bioplastic and replacement of conventional plastic.

scholarly journals Topographical and Biomechanical Guidance of Electrospun Fibers for Biomedical Applications

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2896
Author(s):  
Sara Ferraris ◽  
Silvia Spriano ◽  
Alessandro Calogero Scalia ◽  
Andrea Cochis ◽  
Lia Rimondini ◽  
...  
Keyword(s):  
Surface Modification ◽  
Biomedical Applications ◽  
Biomedical Application ◽  
Electrospun Fibers ◽  
Natural Polymers ◽  
Polymeric Fibers ◽  
Biological Phenomena ◽  
Proper Design ◽  
Synthetic And Natural Polymers ◽  
Selection Of

Electrospinning is gaining increasing interest in the biomedical field as an eco-friendly and economic technique for production of random and oriented polymeric fibers. The aim of this review was to give an overview of electrospinning potentialities in the production of fibers for biomedical applications with a focus on the possibility to combine biomechanical and topographical stimuli. In fact, selection of the polymer and the eventual surface modification of the fibers allow selection of the proper chemical/biological signal to be administered to the cells. Moreover, a proper design of fiber orientation, dimension, and topography can give the opportunity to drive cell growth also from a spatial standpoint. At this purpose, the review contains a first introduction on potentialities of electrospinning for the obtainment of random and oriented fibers both with synthetic and natural polymers. The biological phenomena which can be guided and promoted by fibers composition and topography are in depth investigated and discussed in the second section of the paper. Finally, the recent strategies developed in the scientific community for the realization of electrospun fibers and for their surface modification for biomedical application are presented and discussed in the last section.

scholarly journals Polymeric Bioinks for 3D Hepatic Printing

Chemistry ◽  
2021 ◽  
Vol 3 (1) ◽  
pp. 164-181
Author(s):  
Joyita Sarkar ◽  
Swapnil C. Kamble ◽  
Nilambari C. Kashikar
Keyword(s):  
Tissue Engineering ◽  
3D Printing ◽  
Soft Tissues ◽  
Three Dimensional ◽  
Stem Cell Differentiation ◽  
Synthetic Polymers ◽  
Bioactive Molecules ◽  
Complex Geometries ◽  
Printing Techniques ◽  
Natural And Synthetic

Three-dimensional (3D) printing techniques have revolutionized the field of tissue engineering. This is especially favorable to construct intricate tissues such as liver, as 3D printing allows for the precise delivery of biomaterials, cells and bioactive molecules in complex geometries. Bioinks made of polymers, of both natural and synthetic origin, have been very beneficial to printing soft tissues such as liver. Using polymeric bioinks, 3D hepatic structures are printed with or without cells and biomolecules, and have been used for different tissue engineering applications. In this review, with the introduction to basic 3D printing techniques, we discuss different natural and synthetic polymers including decellularized matrices that have been employed for the 3D bioprinting of hepatic structures. Finally, we focus on recent advances in polymeric bioinks for 3D hepatic printing and their applications. The studies indicate that much work has been devoted to improvising the design, stability and longevity of the printed structures. Others focus on the printing of tissue engineered hepatic structures for applications in drug screening, regenerative medicine and disease models. More attention must now be diverted to developing personalized structures and stem cell differentiation to hepatic lineage.

An Overview of the Interdiffusion Studies in Mo-Si and W-Si Systems

2014 ◽  
Vol 354 ◽  
pp. 79-83
Author(s):  
Soumitra Roy ◽  
Soma Prasad ◽  
Aloke Paul
Keyword(s):  
Crystal Structures ◽  
Atomic Number ◽  
Diffusion Coefficients ◽  
Relative Increase ◽  
The Other ◽  
Reactive Diffusion ◽  
Refractory Elements ◽  
Other Hand ◽  
Two Systems ◽  
Diffusion Rates

The growth of phases by reactive diffusion in Mo-Si and W-Si systems are compared. The crystal structures of MSi2 and M5Si3 phases (M = Mo, W) are similar in these two systems. However, the diffusion rates of the components change systematically with a change in the atomic number. Integrated diffusion coefficients in both phases increase with an increasing atomic number of refractory elements i.e. from Mo to W. On the other hand, the ratio of diffusivities of the components decreases. This indicates a relative increase in the diffusion rates of the metal components with increasing atomic number and a difference in defects concentrations in these two systems.

Natural Polymers in Fast Dissolving Tablets

2021 ◽  
pp. 2859-2866
Author(s):  
Ratnaparkhi M.P. ◽  
Karnawat G.R. ◽  
Andhale R.S.
Keyword(s):  
Geriatric Patients ◽  
Nutritional Supplement ◽  
Synthetic Polymers ◽  
Oral Route ◽  
Water Soluble ◽  
Natural Polymers ◽  
Disintegration Time ◽  
Water Soluble Drug ◽  
Poorly Water Soluble ◽  
Poorly Water Soluble Drug

Oral route is most preferable route of administration for various drugs, because it is convenient, economical, safest route. Fast dissolving tablets are popular nowadays, as they disintegrated in mouth within a few seconds without using water for swallow. Problems like Dysphagia in pediatric and geriatric patients have been overcome by formulating Fast dissolving tablet. Natural polymers are preferable because they are chemically inert, nontoxic, less expensive, biodegradable, and available easily than synthetic polymers. Natural polymers are obtained from the natural origin so they are devoid of any side effect. It is proved from the previous studies that Natural polymers are more-safe and effective than the synthetic polymers. Natural polymers improve the properties of tablet and they are used as binder, diluent, superdisintegrant, they also enhance the solubility of poorly water-soluble drug, decrease the disintegration time and provide nutritional supplement. The aim of the present article is to study various natural polymers used in fast dissolving tablets.

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