Green Chemistry is a relatively new emerging field that strives to work at the molecular level to achieve sustainability. The field has received widespread interest in the past decade due to its ability to harness chemical innovation to meet environmental and economic goals simultaneously. Green Chemistry has a framework of a cohesive set of Twelve Principles, which have been systematically surveyed in this critical review. This article covers the concepts of design and the scientific philosophy of Green Chemistry with a set of illustrative examples. Future trends in Green Chemistry are discussed with the challenge of using the Principles as a cohesive design system (93 references).

Green Chemistry: Principles and Practice

Chitosan-based biomaterials for tissue engineering

This review describes the most common methods for recovery of chitin from marine organisms. In depth, both enzymatic and chemical treatments for the step of deproteinization are compared, as well as different conditions for demineralization. The conditions of chitosan preparation are also discussed, since they significantly impact the synthesis of chitosan with varying degree of acetylation (DA) and molecular weight (MW). In addition, the main characterization techniques applied for chitin and chitosan are recalled, pointing out the role of their solubility in relation with the chemical structure (mainly the acetyl group distribution along the backbone). Biological activities are also presented, such as: antibacterial, antifungal, antitumor and antioxidant. Interestingly, the relationship between chemical structure and biological activity is demonstrated for chitosan molecules with different DA and MW and homogeneous distribution of acetyl groups for the first time. In the end, several selected pharmaceutical and biomedical applications are presented, in which chitin and chitosan are recognized as new biomaterials taking advantage of their biocompatibility and biodegradability.

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Chitin and Chitosan Preparation from Marine Sources. Structure, Properties and Applications

Design and functionalization strategies for multifunctional nanocarriers (e.g., nanoparticles, micelles, polymersomes) based on biodegradable/biocompatible polymers intended to be employed for active targeting and drug delivery are reviewed. This review will focus on the nature of the polymers involved in the preparation of targeted nanocarriers, the synthesis methods to achieve the desired macromolecular architecture, the selected coupling strategy, the choice of the homing molecules (vitamins, hormones, peptides, proteins, etc.), as well as the various strategies to display them at the surface of nanocarriers. The resulting morphologies and the main colloidal features will be given as well as an overview of the biological activities, with a special focus on the main in vivo achievements.

Design, functionalization strategies and biomedical applications of targeted biodegradable/biocompatible polymer-based nanocarriers for drug delivery

Novel chitin and chitosan nanofibers in biomedical applications.

http://www.mtdna.or.kr/neowiz/board/up_files/files_17/Chitin_Chitosan_polymers_chemistrySolubilityFiberFormation.pdf

Chitin and chitosan polymers: Chemistry, solubility and fiber formation

Among biomaterials used as implants in human body, sutures constitute the largest groups of materials having a huge market exceeding $1.3 billion annually. Sutures are the most widely used materials in wound closure and have been in use for many centuries. With the development of the synthetic absorbable polymer, poly(glycolic acid) (PGA) in the early 1970s, a new chapter has opened on absorbable polymeric sutures that got unprecedented commercial successes. Although several comparative evaluations of suture materials have been published, there were no serious attempts of late on a comprehensive review of production, properties, biodegradability, and performance of suture materials. This review proposes to bring to focus scattered data on chemistry, properties, biodegradability, and performance of absorbable polymeric sutures.

Review Paper: Absorbable Polymeric Surgical Sutures: Chemistry, Production, Properties, Biodegradability, and Performance

The electrospinning technique is a versatile method to spin polymers into continuous fibers with diameters ranging from a few micrometers to a few nanometers. Electrospinning creates seemingly endless ultra fine fibers that collect in a random pattern. These nanofibers can form non-woven textile mats, oriented fibrous bundles and even three-dimensional structured scaffolds, all with large surface areas and high porosity. It is, thus, the most extensively used fabrication method that offers vast opportunities for control of the morphology of the electrospun fibers. Due to their intrinsic features, polymeric nanofibers are attractive for biomedical and biotechnological applications such as tissue engineering, nanocomposites for dental application, controlled drug delivery, medical implants, wound dressings, biosensors and filtration. The applications of chitin and chitosan (CS) nanofibers in these areas are reviewed in this paper. Because of the inherent biodegradability, biofunctionality and biocompatibility of the biopolymer, electrospun chitin and CS fibers have special advantages whereby properties such as cytocompatibility, tissue responses etc. could be controlled in critical applications.

Electrospinning of Chitin and Chitosan Nanofibres

Ligand-conjugated delivery vectors that target over-expressed cell surface receptors have a potential impact on gene therapy. In the study reported, high-molecular-weight chitosan was depolymerized to medium and low molecular weight and trimethylated to render the polymer soluble over a wider pH range. Folate conjugation was introduced to the quarternized derivative to improve gene transfection efficiency. Complexes of the folic acid-conjugated trimethylated depolymerized chitosan (FTMC) with plasmid DNA (pDNA) formed core–shell nanostructured particles. Gel electrophoretic band retardation showed efficient condensation of DNA. These derivatives and their complexes with pDNA were tested for toxicity and haemocompatibility and were found to be significantly less toxic and haemocompatible than polyethyleneimine. Transfection efficiency and nuclear uptake properties were tested in the human KB oral epidermoid cell line, which over-expresses the folate receptor in the presence of 10% serum. Among the four FTMC derivatives investigated, folic acid-conjugated chitosan having low molecular weight and medium folate conjugation was found to be a potential vector for gene delivery applications with good transfection and nuclear uptake properties, as proved by YOYO labelling of pDNA. Copyright © 2011 Society of Chemical Industry

C.K.S. Pillai

Papers

Chitin and chitosan polymers: Chemistry, solubility and fiber formation

Review Paper: Absorbable Polymeric Surgical Sutures: Chemistry, Production, Properties, Biodegradability, and Performance

Electrospinning of Chitin and Chitosan Nanofibres

Folic acid‐conjugated depolymerized quaternized chitosan as potential targeted gene delivery vector

Enhanced Cytotoxicity and Cellular Internalization of Hemocompatible Curcumin Loaded Pluronic Linolenate Micelles in Cancer Cells