Compressive Evaluation of Polyethylene (Glycol) Diacrylate (PEGDA) for Scaffold Fabrication

Author(s):  
Ozlem Yasar ◽  
Serkan Inceoglu

In the field of tissue engineering, scaffold is the foundation structure that provides the desired mechanical support for the tissue being engineered, surface for cells to attach and spread, and access for nutrient transport crucial for cell viability. The scaffolds are 3D building blocks which are designed and fabricated precisely prior to its implantation to the host tissue. When scaffolds with desired shape and size are fabricated, they can be seeded with cells and appropriate growth factors. After cells show healthy growth within the scaffold, they are implanted into the body with the scaffold to allow full-scale tissue regeneration. In this research, photolithography is adapted as a fabrication method to generate PEGDA-based structures. In this method, ultra-violet (UV) light is reflected on PEGDA and as a result of the interaction between UV light and precursor solution, PEGDA turns into solid form. Despite the potential of PEGDA in scaffold applications, the mechanical properties have not been studied in a great extent. Therefore, in this project, the mechanical characterization of PEGDA was conducted for various polymer concentrations. Specimens with 20%, 40%, 60%, 80% and 100% PEGDA to water ratio were prepared for compression tests. Our preliminary experimental data results show that, mechanical properties of PEGDA can be controlled by changing the PEGDA to water ratio. Stronger and stiffer structures can be obtained with high PEGDA concentrations while softer structures can be fabricated with reduced PEGDA concentrations.

Author(s):  
Ozlem Yasar ◽  
Serkan Inceoglu ◽  
Ramesh Prashad

In recent years, tissue engineering has been utilized as an alternative approach for the organ transplantation. The success rate of tissue regeneration is influenced by the type of biomaterials, cell sources, growth factors and scaffold fabrication techniques used. The poly(ethylene glycol) diacrylate (PEGDA) is one of commonly used biomaterials because of its biocompatibility, ease of use, and porous microstructure. The mechanical properties of PEGDA have been studied to some extent by several research groups. However, the stability of the mechanical properties with time has not been investigated. In this research, we studied how the mechanical properties of different concentrations of PEGDA change with the post-fabrication ageing time. Cylindrical PEGDA samples were prepared 20%, 40%, 60%, 80%, and 100% concentrations and cured under the UV light. After the solidification process, weight of each sample was monitored in every 0, 2, 4, 6, and 24 hours post-fabrication ageing time until the mechanical testing. Compressive elastic modulus and strength were calculated and statistically analyzed. Our results indicated that the water content of each PEGDA group constantly decreased by time, however, this loss significantly affected the elastic modulus and strength only after 6 hours in some PEGDA concentration.


Micromachines ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 293
Author(s):  
José M. Acosta-Cuevas ◽  
José González-García ◽  
Mario García-Ramírez ◽  
Víctor H. Pérez-Luna ◽  
Erick Omar Cisneros-López ◽  
...  

Photopolymerized microparticles are made of biocompatible hydrogels like Polyethylene Glycol Diacrylate (PEGDA) by using microfluidic devices are a good option for encapsulation, transport and retention of biological or toxic agents. Due to the different applications of these microparticles, it is important to investigate the formulation and the mechanical properties of the material of which they are made of. Therefore, in the present study, mechanical tests were carried out to determine the swelling, drying, soluble fraction, compression, cross-linking density (Mc) and mesh size (ξ) properties of different hydrogel formulations. Tests provided sufficient data to select the best formulation for the future generation of microparticles using microfluidic devices. The initial gelation times of the hydrogels formulations were estimated for their use in the photopolymerization process inside a microfluidic device. Obtained results showed a close relationship between the amount of PEGDA used in the hydrogel and its mechanical properties as well as its initial gelation time. Consequently, it is of considerable importance to know the mechanical properties of the hydrogels made in this research for their proper manipulation and application. On the other hand, the initial gelation time is crucial in photopolymerizable hydrogels and their use in continuous systems such as microfluidic devices.


Materials ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 962 ◽  
Author(s):  
Liberata Guadagno ◽  
Carlo Naddeo ◽  
Marialuigia Raimondo ◽  
Vito Speranza ◽  
Roberto Pantani ◽  
...  

Epoxy based coatings are susceptible to ultra violet (UV) damage and their durability can be significantly reduced in outdoor environments. This paper highlights a relevant property of graphene-based nanoparticles: Graphene Nanoplatelets (GNPs) incorporated in an epoxy-based free-standing film determine a strong decrease of the mechanical damages caused by UV irradiation. The effects of UV light on the morphology and mechanical properties of the solidified nanocharged epoxy films are investigated by Atomic Force Microscopy (AFM), in the acquisition mode “HarmoniX.” Nanometric-resolved maps of the mechanical properties of the multi-phase material evidence that the incorporation of low percentages, between 0.1% and 1.0% by weight, of graphene nanoplatelets (GNPs) in the polymeric film causes a relevant enhancement in the mechanical stability of the irradiated films. The beneficial effect progressively increases with increasing GNP percentage. The paper also highlights the potentiality of AFM microscopy, in the acquisition mode “HarmoniX” for studying multiphase polymeric systems.


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.


2021 ◽  
pp. 088532822110448
Author(s):  
Xiang Zhang ◽  
Zhenhao Yan ◽  
Guotao Guan ◽  
Zijing Lu ◽  
Shujie Yan ◽  
...  

Natural cartilage tissue has excellent mechanical properties and has certain cellular components. At this stage, it is a great challenge to produce cartilage scaffolds with excellent mechanical properties, biocompatibility, and biodegradability. Hydrogels are commonly used in tissue engineering because of their excellent biocompatibility; however, the mechanical properties of commonly used hydrogels are difficult to meet the requirements of making cartilage scaffolds. The mechanical properties of high concentration polyethylene glycol diacrylate (PEGDA) hydrogel are similar to those of natural cartilage, but its biocompatibility is poor. Low concentration hydrogel has better biocompatibility, but its mechanical properties are poor. In this study, two different hydrogels were combined to produce cartilage scaffolds with good mechanical properties and strong biocompatibility. First, the PEGDA grid scaffold was printed with light curing 3D printing technology, and then the low concentration GelMA/Alginate hydrogel with chondral cells was filled into the PEGDA grid scaffold. After a series of cell experiments, the filling hydrogel with the best biocompatibility was screened out, and finally the filled hydrogel with cells and excellent biocompatibility was obtained. Cartilage tissue engineering scaffolds with certain mechanical properties were found to have a tendency of cartilage formation in in vitro culture. Compared with the scaffold obtained by using a single hydrogel, this molding method can produce a tissue engineering scaffold with excellent mechanical properties on the premise of ensuring biocompatibility, which has a certain potential application value in the field of cartilage tissue engineering.


2011 ◽  
Vol 1312 ◽  
Author(s):  
Alessandro Chiolerio ◽  
Paolo Allia ◽  
Paola Tiberto ◽  
Lorenza Suber ◽  
Giada Marchegiani ◽  
...  

ABSTRACTAcrylic based films containing thermo-chemically synthesized magnetite nanoparticles (NPs) were prepared by UV-curing. A stable dispersion of Fe3O4 NPs in n-hexane was added to polyethylene glycol diacrylate (PEGDA) oligomer or to hexanediol diacrylate (HDDA) oligomer, producing a blend whose viscosity matches the processing requirements for inkjet printing technology. Morphologic characterization is provided by means of Field Effect SEM on a representative nanocomposite section.By real-time FT-IR analysis it was shown that Fe3O4 NPs are able to initiate radical chain-grown polymerization under UV light, for what concerns the HDDA matrix. Tight cross-linked transparent polymeric films were obtained after 1 minute of UV irradiation.The magnetic properties of the produced films were studied by means of an Alternating-Gradient Force Magnetometer (AGFM) in the temperature range 10 – 300 K and up to 18 kOe. The isothermal magnetization curves of both HDDA and PEGDA -based nanocomposites showed that these hybrid systems must be described as interacting superparamagnets (ISP) characterized by inter-particle magnetic interactions dominating over intra-particle effects.


2006 ◽  
Vol 980 ◽  
Author(s):  
Hideki Hosoda ◽  
Tomonari Inamura ◽  
Kenji Wakashima

AbstractMechanical properties and phase constitution of an E21-type Ti3AlC-base alloy were investigated by compression tests in a temperature range from room temperature (RT) to 1273K, scanning electron microscopy (SEM) and X-ray diffraction analysis (XRD). The unit cell of E21 Ti3AlC is constructed by ¡§L12 Ti3Al¡¨ and a carbon atom occupying the body-center octahedral-interstitial-site surrounded by the Ti atoms. The nominal composition of the alloy was chosen to be the stoichiometric composition of 60mol%Ti-20mol%Al-20mol%C. The alloy was synthesized by mechanical alloying using high purity elemental powders followed by hot pressing at 1473K for 3hrs. It was found by XRD and SEM that the alloy was mainly composed of E21 Ti3AlC in addition to Cr2AlC-type Ti2AlC precipitates as a second phase. The density of Ti3AlC is calculated to be 4.29g/cm3 based on the lattice parameter of 0.4134nm of E21. The average grain size was 2μm by SEM. By the compression tests, the 0.2% flow stress at the temperature range from RT to 1073K exceeded 1GPa. The yield stress is comparably higher than those of other E21 intermetallic carbides: at 1073K, 1084MPa for Ti3AlC, 50MPa for Mn3AlC and 135MPa for Fe3AlC. Besides, a weak positive temperature dependence of strength was observed where the peak temperature was around 900K. This suggests that a Kear-Wilsdorf type dislocation pinning mechanism may be activated. It is concluded that E21 Ti3AlC-base alloy shows promise for a new high-temperature light-weight structural material.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Laura Zorzetto ◽  
Luca Andena ◽  
Francesco Briatico-Vangosa ◽  
Lorenzo De Noni ◽  
Jean-Michel Thomassin ◽  
...  

AbstractIn polyjet printing photopolymer droplets are deposited on a build tray, leveled off by a roller and cured by UV light. This technique is attractive to fabricate heterogeneous architectures combining compliant and stiff constituents. Considering the layer-by-layer nature, interfaces between different photopolymers can be formed either before or after UV curing. We analyzed the properties of interfaces in 3D printed composites combining experiments with computer simulations. To investigate photopolymer blending, we characterized the mechanical properties of the so-called digital materials, obtained by mixing compliant and stiff voxels according to different volume fractions. We then used nanoindentation to measure the spatial variation in mechanical properties across bimaterial interfaces at the micrometer level. Finally, to characterize the impact of finite-size interfaces, we fabricated and tested composites having compliant and stiff layers alternating along different directions. We found that interfaces formed by deposition after curing were sharp whereas those formed before curing showed blending of the two materials over a length scale bigger than individual droplet size. We found structural and functional differences of the layered composites depending on the printing orientation and corresponding interface characteristics, which influenced deformation mechanisms. With the wide dissemination of 3D printing techniques, our results should be considered in the development of architectured materials with tailored interfaces between building blocks.


Gels ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 160
Author(s):  
Erlin Arda Safitri ◽  
I Putu Mahendra ◽  
Anggi Eka Putra ◽  
M Alvien Ghifari ◽  
Demi Dama Yanti ◽  
...  

Colorimetric indicator gels were developed by incorporating anthocyanin (AC) obtained from red cabbage into poly (ethylene glycol) diacrylate (PEGDA)-based hydrogel containing lignocellulose nanofiber (LCNF). The PEGDA-based hydrogel was prepared by mixing all of the mentioned components at the specific composition, and the hydrogels were cured under UV light (245 nm) for 1 min. The pH-response, UV absorption, swelling ratio, and mechanical properties of PEGDA/LCNF were determined. It was further found that PEGDA and LCNF mount play an important role in adjusting the mechanical properties of PEGDA/LCNF. In general, the presence of LCNF improved the mechanical properties and swelling ratio of PEGDA. The incorporation of red cabbage anthocyanin into the PEGDA/LCNF film showed multicolor response when specific pH buffers were introduced. Based on the multicolor response of PEGDA/LCNF/CA, this gel film indicator can be developed as a food freshness indicator that focuses on the detection of ammonia and amine compound.


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