One method of improving the water solubility, outlined by Farag et al. , is carboxymethylation of chitosan. Carboxymethylation introduces carboxymethyl groups (-CH 2 -COOH) into the structure of chitosan. The carboxymethyl groups improve the solubility because the groups are hydrophilic (water-attracting), meaning that the chitosan has a higher affinity for water, resulting in a higher solubility and better dispersion of the nanoparticles in stable environments. The newly enhanced carboxymethyl chitosan can be used in a variety of biomedical situations, especially drug delivery, with a better outcome than normal CSNPs. These carboxymethyl chitosan nanoparticles (CMCSNPs) were synthesized using the method indicated by Farag et al., where the carboxymethyl chitosan was combined with polyvinyl alcohol, forming nanogels. The nanogels formed with this procedure range in size from only a few nanometers to 1,000 nanometers and have a large surface area with good surface properties. Thus, with more optimal properties, the release of drugs can be better controlled with greater stability. With such a minuscule size, the nanogels can cross biological boundaries including cell membranes, to reach specific sites within cells, ultimately making the CMCSNPs more applicable to situations where a controlled release of drugs is necessary. Furthermore, the better release properties of CMCSNPs result in more effective performance in environments with varying pH levels throughout the body, highlighting their implications in the biomedical field.