scholarly journals Preparation and Characterisation of Cellulose Nanocrystal/Alginate/Polyethylene Glycol Diacrylate (CNC/Alg/PEGDA) Hydrogel Using Double Network Crosslinking Technique for Bioprinting Application

2022 ◽  
Vol 12 (2) ◽  
pp. 771
Author(s):  
Anusha Wei Asohan ◽  
Rokiah Hashim ◽  
Ku Marsilla Ku Ishak ◽  
Zuratul Ain Abdul Hamid ◽  
Nurshafiqah Jasme ◽  
...  

In this study, we aimed to prepare and characterise hydrogel formulations using cellulose nanocrystals (CNCs), alginate (Alg), and polyethylene glycol diacrylate (PEGDA). The CNC/Alg/PEGDA formulations were formed using a double network crosslinking approach. Firstly, CNC was extracted from oil palm trunk, and the size and morphology of the CNCs were characterised using TEM analysis. Secondly, different formulations were prepared using CNCs, Alg, and PEGDA. The mixtures were crosslinked with Ca2+ ions and manually extruded using a syringe before being subjected to UV irradiation at 365 nm. The shear-thinning properties of the formulations were tested prior to any crosslinking, while the determination of storage and loss modulus was conducted post extrusion after the Ca2+ ion crosslink using a rheometer. For the analysis of swelling behaviour, the constructs treated with UV were immersed in PBS solution (pH 7.4) for 48 h. The morphology of the UV crosslinked construct was analysed using SEM imaging. The extracted CNC exhibited rod-like structures with an average diameter and length of around 7 ± 2.4 and 113 ± 20.7 nm, respectively. Almost all CNC/Alg/PEGDA formulations (pre-gel formulation) displayed shear-thinning behaviour with the power-law index η < 1, and the behaviour was more prominent in the 1% [w/v] Alg formulations. The CNC/Alg/PEGDA with 2.5% and 4% [w/v] Alg displayed a storage modulus dominance over loss modulus (G′ > G″) which suggests good shape fidelity. After the hydrogel constructs were subjected to UV treatment at 365 nm, only the F8 construct [4% CNC: 4% Alg: 40% PEGDA] demonstrated tough and flexible characteristics that possibly mimic the native articular cartilage property due to a similar water content percentage (79.5%). In addition, the small swelling ratio of 4.877 might contribute to a minimal change of the 3D construct’s geometry. The hydrogel revealed a rough and wavy surface, and the pore size ranged from 3 to 20 µm. Overall, the presence of CNCs in the double network hydrogel demonstrated importance and showed positive effects towards the fabrication of a potentially ideal 3D bioprinted scaffold.

Polymers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 845
Author(s):  
Xin Yang ◽  
Bronwin Dargaville ◽  
Dietmar Hutmacher

The interaction of water within synthetic and natural hydrogel systems is of fundamental importance in biomaterial science. A systematic study is presented on the swelling behavior and states of water for a polyethylene glycol-diacrylate (PEGDA)-based model neutral hydrogel system that goes beyond previous studies reported in the literature. Hydrogels with different network structures are crosslinked and swollen in different combinations of water and phosphate-buffered saline (PBS). Network variables, polyethylene glycol (PEG) molecular weight (MW), and weight fraction are positively correlated with swelling ratio, while “non-freezable bound water” content decreases with PEG MW. The presence of ions has the greatest influence on equilibrium water and “freezable” and “non-freezable” water, with all hydrogel formulations showing a decreased swelling ratio and increased bound water as ionic strength increases. Similarly, the number of “non-freezable bound water” molecules, calculated from DSC data, is greatest—up to six molecules per PEG repeat unit—for gels swollen in PBS. Fundamentally, the balance of osmotic pressure and non-covalent bonding is a major factor within the molecular structure of the hydrogel system. The proposed model explains the dynamic interaction of water within hydrogels in an osmotic environment. This study will point toward a better understanding of the molecular nature of the water interface in hydrogels.


2014 ◽  
Vol 2 (42) ◽  
pp. 7429-7439 ◽  
Author(s):  
Anuj Kumar ◽  
Sabindra K. Samal ◽  
Rupesh Dash ◽  
Umaprasana Ojha

The synthesis and characterization of a series of injectable and stimuli responsive hydrogels based on polyacryloyl hydrazide have been accomplished using dimethyl 2,2′-thiodiacetate, acrylic acid, diethyl malonate and polyethylene glycol diacrylate as cross-linkers through a chemical or dual cross-linking pathway.


2014 ◽  
Vol 941-944 ◽  
pp. 404-410 ◽  
Author(s):  
Young Ho Kim ◽  
Jeong Woo Sohn ◽  
Youngjae Woo ◽  
Joo Hyun Hong ◽  
Juyoung Park

Polyethylene glycol (PEG) hydrogel microstructures with various shapes and sizes on a glass chip were prepared by a simple and rapid ultraviolet (UV) irradiation method using a metal mask. Photocurable PEG solution prepared by mixing 95 wt.% polyethylene glycol diacrylate and 5 wt.% 2-hydroxy-2-methylpropiophenone as a photo-initiator was injected to the gap between bottom and upper glasses in a simply assembled glass chip. After a metal mask with line-and-space or complex patterns was placed on the glass chip, UV light from a spot UV irradiation device was exposed to the glass chip through the metal mask for 7 seconds at UV intensity of 26 mW/cm2. Then the PEG hydrogel micropatterns on the glass chip were obtained after removing unreacted PEG solution by air blowing. To prepare more rigid microstructure, the prepared PEG micropatterned chip was exposed under UV light for 20 seconds. Then the PEG hydrogel micropattern chip was fabricated by a simple and rapid procedure. Micropattern transferring was performed from the PEG hydrogel chip to polydimethyl siloxane (PDMS) replica by a solution casting. The prepared micropatterned PDMS replicas showed similar shape and size of microstructures compared to that of the corresponded PEG hydrogel chip. Thus the PEG hydrogel microstructures on a glass chip could be used as a mold to fabricate micropattern PDMS chips for nanobio-chip applications. Furthermore, the present method provides large scale chip fabrication, more than 4 cm-length and 4 cm-width in a single step, not only PEG hydrogel chips but also PDMS chips.


2011 ◽  
Vol 83 (16) ◽  
pp. 6418-6425 ◽  
Author(s):  
Chad I. Rogers ◽  
Jayson V. Pagaduan ◽  
Gregory P. Nordin ◽  
Adam T. Woolley

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