Technical Papers and Presentations

Currently, there is a great interest in the study of gels, especially their transport or release properties. Hydrogels have countless definitions, but generally speaking, they are hydrophilic systems with a three-dimensional structure that tend to swell and hold large amounts of water and physiological fluids in their structure, which ultimately leads to increased biodegradability and biocompatibility. These properties give them diversity and versatility in various fields of human activity, making them ideal candidates for various applications such as targeted drug delivery, tissue engineering, etc. [1]. Transport modeling, or release of a substance from a gel system into a biological environment using COMSOL Multiphysics® plays an important role in understanding the processes required for proper design and optimization of a suitable model [2]. This model should have the ability to accurately simulate transport, or release of substances from a gel three-dimensional structure in a certain biological environment (organism, soil). The goal of this work is to design a model corresponding to a real sample of fertilizer or gel balls containing a medicinal or bioactive substance, or is filled with a model dye (e.g. methylene blue) for determining release properties using appropriate experimental methods. Parameters such as geometry and material properties for individual parts of the model were first set in the COMSOL Multiphysics® software. The model represents the presence in the biological environment of a sphere containing a model substance with a concentration of 0.5 M and coated with a thin layer of polymer, enabling controlled release. The blank material for the sphere model was used to set the diffusion coefficient and porosity of the polymer membrane, where water, as a material from the material library, was chosen to define the biological environment. Simulations were performed using the Transport of Diluted Species interface, providing modeling of the diffusion of a substance across a membrane and tracking its release into the biological environment, and Laminar Flow, with gravity turned on and the flow rate being zero. Using COMSOL Multiphysics®, we were able to quantitatively evaluate the release process of a model substance through a polymer membrane into the biological environment and investigate the influence of various factors, including changes in the values of the diffusion coefficient and porosity of the polymer membrane. In the study devoted to time dependence, all the obtained data indicate that by changing the diffusion coefficient or porosity, the course of release of the model substance can be influenced, which makes it possible to change the transport or release properties of hydrogel systems according to the desired applications.