Photocrosslinked Chitosan Hydrogels Reinforced with Chitosan‐Derived Nano‐Graphene Oxide

Abstract

Chitosan and chitosan‐derived nano‐graphene oxide carbon dots are successfully methacrylated and utilized for the fabrication of photocurable hydrogels. The addition of the nano‐graphene oxide (nGO) does not significantly delay the polymer network build‐up, but significantly reduces the storage modulus of the crosslinked network, with important detrimental effects on the mechanical performance. By replacing nGO with methacrylated M‐nGO, the mechanical performance of the crosslinked polymer network is improved with an increase of the storage modulus as a function of increasing the M‐nGO content in the photocurable formulation.

Microwave-assisted methacrylation of chitosan for 3D printable hydrogels in tissue engineering

“…The highest DS level is reached at a ratio of 1:4 followed by a sort of plateau. The obtained value is similar to values reported in literature for traditional syntheses 37 , while the DS plateau can be attributed to steric hindrance limitations.…”

“…A representative 1 H-NMR spectrum of CHI-MA is also presented (Figure 2B, Spectre referred to other synthesis are reported in Figure S2, Supporting Info). The successful incorporation of methacrylate groups was confirmed by the presence of FTIR signal at 1620 cm -1 (C=C) 4 and by the shifting of the characteristic peak of amine I stretching at lower wavenumbers (1639 cm -1 ) 37 for all the samples. The coupling of MA with the hydroxyl group of chitosan was demonstrated by the formation of the ester band at 1710 cm -1 40 .…”

“…These peaks can be attributed to the methylene protons of acrylates. In particular, the peaks at 5.4 and 5.6 (yellow and green of Figure 2B) are assigned to the protons in C=CH 2 after methacrylation of amine-groups and those at 5.6 and 6 (green and blue on Figure 2B) indicated same protons after methacrylation of hydroxyl groups 34,37,44 . Integrating and normalizing these peaks and those of the potential reactive sites permits the calculation of the degree of substitution (DS) for methacrylation of the NH 2 and OH groups; the data collected for the samples prepared with different chitosan: MA ratios are illustrated in Figure 2C.…”

“…the amino groups and the primary and secondary hydroxyl groups) is shown in Figure 1 followed by methacrylation reaction scheme to produce CHI-MA. Based on previous research with traditional methacrylation, it is expected that the methacrylation can occur either on the hydroxyl or amine groups of chitosan 37 .…”

Light Processable Starch Hydrogels

“…They have many advantages with respect to the thermocuring processes such as absence of Volatile Organic Compound (VOC) emissions, high curing speed, reduced energy consumption, and no heat requirements [ 13 , 14 , 15 ]. Recently UV curable biopolymer-resins have gained increasing interest [ 16 , 17 ]. For example, cationic UV-curable starch-based coatings were created by grafting of glycidyl methacrylate (GMA) onto the starch structure [ 18 ].…”