Tham khảo tài liệu 'biomedical engineering trends in materials science part 12', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 322 Biomedical Engineering Trends in Materials Science Fig. 2. Effect of w v PEG-DA in prepolymer on the thickness of GLP-1 functionalized PEG hydrogel membrane TEA 225 mM acrl-PEG-GLP-1 14. 8 pM 25 w v PEG Fig. 3. Effect of concentration changes of VP on the thickness of GLP-1 functionalized PEG hydrogel membrane TEA 225 mM acrl-PEG-GLP-1 14. 8 pM and 25 w v PEG-DA in prepolmer solution. For all the conditions studied the thickness of the hydrogel membrane increases rapidly with time during the early stages of photopolymerization and then saturates to the maximum value Figure 3 . Therefore once the saturation thickness is obtained longer photopolymerization times would not result in higher membrane wall thickness. This was explained by the limited diffusion of photoinitiator through the newly formed hydrogel membrane. Higher thicknesses achieved for higher photoinitiator concentrations condition is caused by the formation and diffusion of more radical fragment Rin through the hydrogel membrane which increases total amount of polymer hydrogel in the medium. Recent Advances in the Modeling of PEG Hydrogel Membranes for Biomedical Applications 323 In addition to the comparison of thicknesses of the model and experiments swelling experiments were used to confirm the capability of the model to capture dynamic features of experiments. Swelling ratios for 25 w v PEG-DA concentration acrl-PEG-GLP-1 14. 8 pM TEA 225 mM and VP concentrations within the range of 19-592 mM is compared with the dimensionless crosslink density of the model Figure 4 . Crosslink density is a physical property related to the permeability of hydrogel. Therefore high crosslink densities indicate that the permeability and swelling ratio of the hydrogel is low whereas hydrogels with higher permeabilities and swelling ratios have lower crosslink densities. As shown in Figure 4 inverse of the swelling ratio has similar trend with the dimensionless crosslink density versus VP concentration. Both .
