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Topic Review
Chiral Monolithic Silica-Based HPLC Columns
Ultrahigh pressure HPLC is based on the use of small sub-2-µm non-porous particle packed columns that can provide large surface area than the classical particle packed stationary phase for more efficient separation thus allowing the use of shorter columns with equivalent resolution to save the analysis time. The accompanied high back pressure of the small particle packed columns is overcoming by running the column in an ultrahigh pressure HPLC instrument that can resist high back pressure of up to 15,000 psi or 10,000 psi for longer column lifetimes. This has been achieved by the introduction of UHPLC system to run the chromatographic process with the sub-2-µm particle packed columns. 
  • 539
  • 31 Aug 2021
Topic Review
Chiral Porous Organic Frameworks
Organocatalysis, the use of chiral organic molecules as catalysts, has emerged as a highly efficient alternative to traditional asymmetric catalysis methods. Chiral porous organic frameworks have emerged as candidates for heterogeneous asymmetric organocatalysis.
  • 240
  • 20 Jul 2023
Topic Review
Chitin
       Chitin, being the second most abundant biopolymer after next to cellulose, has been gaining popularity since its initial first discovery by Braconot in 1811. However, fundamental knowledge and literature on about chitin and its derivatives from insects are difficult to obtain. The most common and sought-after sources of chitin are shellfishes (especially crustaceans) and other aquatic invertebrates. The amount of shellfishes available is obviously restricted by the amount of food waste that is allowed; hence, it is a limited resource. Therefore,Hence, insects are the best choices since, out of 1.3 million species in the world, 900,000 are insects, making them the most abundant species in the world. In this review, a total of 82 samples from shellfishes—crustaceans and mollusks (n = 46), insects (n = 23), and others (n = 13)—have been collected and studied for their chemical extraction of chitin and its derivatives. The aim of this paper is to review the extraction method of chitin and chitosan for a comparison of the optimal demineralization and deproteinization processes with, so as to consideration of insects as alternative sources of chitin. The methods employed in this review are based on comprehensive bibliographic research. Based on previous data, chitin and chitosan yield contents of insects in their study favorably compares and competes with those of commercial chitin and chitosan—for example, 45% in Bombyx eri, 36.6% in Periostracum cicadae (cicada sloughs), and 26.2% in Chyrysomya megacephala. Therefore, according to the data reported by previous researchers, with comparable yield values to those of against crustacean chitin and the great interests of in insects as alternative sources, efforts towards comprehensive knowledge in this field are relevant.
  • 2.4K
  • 30 Oct 2020
Topic Review
Chitin and Chitosan
Chitin and its derivative chitosan are highly abundant polymers in nature, appearing in both the shells and exoskeletons of various marine and non-marine species. Since they possess favorable properties, such as biocompatibility, biodegradability, non-toxicity, and non-immunogenicity, they have gained recent attention due to their enormous potential biomedical applications. The polycationic surface of chitosan enables it to form hydrogenic and ionic bonds with drug molecules, which is one of its most useful properties. Because chitosan is biocompatible, it can therefore be used in drug delivery systems. The development of chitosan-based nanoparticles has also contributed to the significance of chitin as a drug delivery system that can deliver drugs topically. Furthermore, chitin can be used in cancer treatment as a vehicle for delivering cancer drugs to a specific site and has an antiproliferative effect by reducing the viability of cells. Finally, chitosan can be used as a wound dressing in order to promote the faster regeneration of skin epithelial cells and collagen production by fibroblasts.
  • 1.2K
  • 01 Aug 2022
Topic Review
Chitosan Adsorbent
Chitin is mentioned as the second most abundant and important natural biopolymer in worldwide scale. The main sources for the extraction and exploitation of this natural polysaccharide polymer are crabs and shrimps. Chitosan (poly-β-(1 → 4)-2-amino-2-deoxy-d-glucose) is the most important derivative of chitin and can be used in a wide variety of applications including cosmetics, pharmaceutical and biomedical applications, food, etc., giving this substance high value-added applications. Moreover, chitosan has applications in adsorption because it contains amino and hydroxyl groups in its molecules, and can thus contribute to many possible adsorption interactions between chitosan and pollutants (pharmaceuticals/drugs, metals, phenols, pesticides, etc.). However, it must be noted that one of the most important techniques of decontamination is considered to be adsorption because it is simple, low-cost, and fast. 
  • 1.3K
  • 01 Jun 2021
Topic Review
Chitosan and Chitosan Modified by Functionalization
The biomedical and therapeutic importance of chitosan and chitosan derivatives is the subject of interdisciplinary research. In this entry, researchers intended to consolidate some of the recent discoveries regarding the potential of chitosan and its derivatives to be used for biomedical and other purposes. Why chitosan? Because chitosan is a natural biopolymer that can be obtained from one of the most abundant polysaccharides in nature, which is chitin. Compared to other biopolymers, chitosan presents some advantages, such as accessibility, biocompatibility, biodegradability, and no toxicity, expressing significant antibacterial potential. In addition, through chemical processes, a high number of chitosan derivatives can be obtained with many possibilities for use. 
  • 1.4K
  • 02 Apr 2022
Topic Review
Chitosan and Fibroin
For the creation of tissue-engineered structures based on natural biopolymers with the necessary chemical, physical, adhesive, morphological, and regenerative properties, biocompatible materials based on polysaccharides and proteins are used.  This entry is devoted to a problem of the technology of polymeric materials for biomedical purposes: the creation of biopolymer tissue engineering matrix and the development of a methodology for studying morphology and functional properties of their surface to establish the prospects for using the material for contact with living objects.
  • 786
  • 12 Apr 2021
Topic Review
Chitosan and its Derivatives
Chitosan (CS) is a hemi-synthetic cationic linear polysaccharide produced by the deacetylation of chitin. CS is non-toxic, highly biocompatible, and biodegradable, and it has a low immunogenicity. Additionally, CS has inherent antibacterial properties and a mucoadhesive character and can disrupt epithelial tight junctions, thus acting as a permeability enhancer. As such, CS and its derivatives are well-suited for the challenging field of ocular drug delivery. In the present review article, we will discuss the properties of CS that contribute to its successful application in ocular delivery before reviewing the latest advances in the use of CS for the development of novel ophthalmic delivery systems. Colloidal nanocarriers (nanoparticles, micelles, liposomes) will be presented, followed by CS gels and lenses and ocular inserts. Finally, instances of CS coatings, aiming at conferring mucoadhesiveness to other matrixes, will be presented.
  • 1.0K
  • 31 Jul 2020
Topic Review
Chitosan and Its Derivatives in Promoting Drug Permeation
Chitosan is the product of N-deacetylation of chitin. Due to the simultaneous presence of amino, acetamido, and hydroxyl groups in the molecule, chitosan is quite active in nature and can be modified, activated, and coupled, showing rich functionality and modifiability in biological applications. As the only polycationic polymer of natural origin, chitosan is capable of interacting with negatively charged cell membranes to assist the loading of drugs across the cell membrane.
  • 550
  • 21 Apr 2022
Topic Review
Chitosan as a Biomaterial
Chitosan remarkable properties have aroused the interest of applying this material in several biomedical applications, such as tissue engineering, wound dressing, drug delivery, and cancer treatment, what has aroused the interest of this review to gather the state-of-the-art concerning this polysaccharide when used as a biomaterial, providing information about its characteristics, chemical modifications, and applications.
  • 654
  • 25 Nov 2020
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