scholarly journals Azo-Dyes-Grafted Oligosaccharides—From Synthesis to Applications

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3063
Author(s):  
Estelle Léonard ◽  
Antoine Fayeulle

Azobenzenes are photochromic molecules that possess a large range of applications. Their syntheses are usually simple and fast, and their purifications can be easy to perform. Oligosaccharide is also a wide family of biopolymer constituted of linear chain of saccharides. It can be extracted from biomass, as for cellulose, being the principal constituent of plant cell wall, or it can be enzymatically produced as for cyclodextrins, having properties not far from cellulose. Combining these two materials families can afford interesting applications such as controlled drug-release systems, photochromic liquid crystals, photoresponsive films or even fluorescent indicators. This review will compile the different syntheses of azo-dyes-grafted oligosaccharides, and will show their various applications.

Author(s):  
D. Reis ◽  
B. Vian ◽  
J. C. Roland

Wall morphogenesis in higher plants is a problem still open to controversy. Until now the possibility of a transmembrane control and the involvement of microtubules were mostly envisaged. Self-assembly processes have been observed in the case of walls of Chlamydomonas and bacteria. Spontaneous gelling interactions between xanthan and galactomannan from Ceratonia have been analyzed very recently. The present work provides indications that some processes of spontaneous aggregation could occur in higher plants during the formation and expansion of cell wall.Observations were performed on hypocotyl of mung bean (Phaseolus aureus) for which growth characteristics and wall composition have been previously defined.In situ, the walls of actively growing cells (primary walls) show an ordered three-dimensional organization (fig. 1). The wall is typically polylamellate with multifibrillar layers alternately transverse and longitudinal. Between these layers intermediate strata exist in which the orientation of microfibrils progressively rotates. Thus a progressive change in the morphogenetic activity occurs.


2018 ◽  
Vol 68 (12) ◽  
pp. 2925-2918
Author(s):  
Gabriela Cioca ◽  
Maricel Agop ◽  
Marcel Popa ◽  
Simona Bungau ◽  
Irina Butuc

One of the main challenges in designing a release system is the possibility to control the release rate in order to maintain it at a constant value below a defined limit, to avoid exceeding the toxicity threshold. We propose a method of overcoming this difficulty by introducing the drug into liposomes, prior to its inclusion in the hydrogel. Furthermore, a natural cross linker (as is tannic acid) is used, instead of the toxic cross linkers commonly used, thus reducing the toxicity of the release system as a whole.


2018 ◽  
Vol 14 (5) ◽  
pp. 432-439 ◽  
Author(s):  
Juliana M. Juarez ◽  
Jorgelina Cussa ◽  
Marcos B. Gomez Costa ◽  
Oscar A. Anunziata

Background: Controlled drug delivery systems can maintain the concentration of drugs in the exact sites of the body within the optimum range and below the toxicity threshold, improving therapeutic efficacy and reducing toxicity. Mesostructured Cellular Foam (MCF) material is a new promising host for drug delivery systems due to high biocompatibility, in vivo biodegradability and low toxicity. Methods: Ketorolac-Tromethamine/MCF composite was synthesized. The material synthesis and loading of ketorolac-tromethamine into MCF pores were successful as shown by XRD, FTIR, TGA, TEM and textural analyses. Results: We obtained promising results for controlled drug release using the novel MCF material. The application of these materials in KETO release is innovative, achieving an initial high release rate and then maintaining a constant rate at high times. This allows keeping drug concentration within the range of therapeutic efficacy, being highly applicable for the treatment of diseases that need a rapid response. The release of KETO/MCF was compared with other containers of KETO (KETO/SBA-15) and commercial tablets. Conclusion: The best model to fit experimental data was Ritger-Peppas equation. Other models used in this work could not properly explain the controlled drug release of this material. The predominant release of KETO from MCF was non-Fickian diffusion.


Author(s):  
Venkatasubramanian Sivakumar

Background: In the growing environmental concern use of natural products, efficient processes and devices are necessary. Solid-Liquid extraction of active Ingredients from Plant materials is one of the important unit operations in Chemical Engineering and need to be enhanced. Objectives: Since, these active ingredients are firmly bound to the plant cell wall membrane, which pose mass-transfer resistance and need to get detached through the use of suitable process intensification tools such as ultrasound and suitable devices. Therefore, detailed analysis and review is essential on development made in this area through Publications and Patents. Hence, the present paper illustrates the development of ultrasound assisted device for solid-liquid extraction are presented in this paper. Methods: Advantages such as % Yield, Reduction in extraction time, use of ambient conditions, better process control, avoidance or minimizing multi stage extraction could be achieved due to the use of ultrasound in extraction as compared to conventional processes. Conclusions: Use of ultrasound to provide significant improvements in the extraction of Vegetable tannins, Natural dyes for application in Leather processing has been demonstrated and reported earlier. These enhancement could be possible through various effects of ultrasound such as better flow of solvents through micro-jet formation, mass transfer enhancement due to rupture of plant cell wall membranes through acoustic cavitation, better leaching due to micro-mixing and acoustic streaming effects. This approach would minimize material wastage; thereby, leading to eco-conservation of plant materials, which is very much essential for better environment. Hence, various methods and design for application of ultrasound assisted solid-liquid extractor device are necessary.


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