Drawbacks and Challenges

8 Current advancement of Chitosan-Based Polyelectrolyte Complexes with Natural Polysaccharides for Drug Delivery 

Polysaccharides Preparation method PEC forms Biomedical applications 

Hyaluronic acid Extrusion w/or w/o TPP layer-by-layer assembly Nanoparticles microparticles films/ membranes Drug delivery Tissue engineering 

Carrageenan Extrusion, w/or w/o TPP Composite with nanotubes Nanoparticles microparticles hydrogel beads fibers Drug delivery Enzyme immobilization 

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Leonard, W. J., Geracce, W. X Dufresne, R. X 2001. Questions first (Qlst) the challenges, benefhs, drawbacks, and results of asking students questions prior to formal instruction. Proceedings of the 2001 Physics Education Research Conference, 41-44. 

These factors have greatly hmited the widespread use of online instmmentation, especially for large-scale monitoring. It is a real challenge to develop novel schemes capable to overcome these drawbacks and limitations and at the same time turn on the classical methodologies in more environmentally friendly ones. Recent advances in materials science, microelectronics, miniaturization, electro-optics, and computer capabilities have made that possible, enabling better instrumentation developments which, combined with statistical tools, provide emerging techniques and novel applications. 

As shown above, a,o)-diynes are reactive substrates in [2 + 2 + 2]-cycloaddition chemistry. However, a limitation of the use of a,o)-diynes is the presence of a secondary fiised-ring system in the arene product. A more flexible synthetic strategy that does not need the tether is desired. [2 + 2 + 2] Cycloaddition of monoynes is a challenging target in the synthesis of polysubstituted benzenes. However, selectivity is a drawback, and the development of a highly selective catalyst is desired. 

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