scholarly journals 3D printing nanocomposite hydrogels with lattice vascular networks using stereolithography

2021 ◽  
Author(s):  
Livia M. Kalossaka ◽  
Ali A. Mohammed ◽  
Giovanni Sena ◽  
Laura Barter ◽  
Connor Myant
Keyword(s):  
Vascular Networks ◽  
Fabrication Technique ◽  
Polyethylene Glycol Diacrylate ◽  
Glycol Diacrylate ◽  
Nanocomposite Hydrogels ◽  
Structural And Functional Properties ◽  
Controlled Porosity ◽  
Optimisation Procedure ◽  
Advanced Applications

AbstractHydrogels have emerged as leading candidates to reproduce native extracellular matrix. To provide structures and functions similar to tissues in vivo, controlled porosity and vascular networks are required. However, fabrication techniques to introduce these are still limited. In this study we propose stereolithography as a fabrication technique to achieve 3D vascular networks using water-based solvents only. A 3D printable hydrogel is formulated based on available commercial chemicals such as acrylamide (AAm) and polyethylene glycol diacrylate 700 (PEGDA700), with nanocellulose crystals (CNC) as a nanofiller. An optimisation procedure to increase resolution, tune porosity as well as mechanical properties is developed. The results highlight the importance of photoabsorber addition to improve channel resolution. We demonstrate that with the adequate choice of chemicals and fillers for photocurable formulations, structural and functional properties of the fabricated scaffold can be tailored, opening the path for advanced applications. Graphic abstract

Altered phenotypic gene expression of 10T1/2 mesenchymal cells in nonuniformly stretched PEGDA hydrogels

2013 ◽  
Vol 305 (1) ◽  
pp. C100-C110 ◽  
Author(s):  
W. J. Richardson ◽  
E. Wilson ◽  
J. E. Moore
Keyword(s):  
Mechanical Loading ◽  
Three Dimensional ◽  
Cell Types ◽  
Vascular Wall ◽  
Mesenchymal Cells ◽  
Brdu Incorporation ◽  
Polyethylene Glycol Diacrylate ◽  
Glycol Diacrylate

Disease-related phenotype modulation of many cell types has been shown to be closely related to mechanical loading conditions; for example, vascular smooth muscle cell (SMC) phenotype shift from a mature, contractile state to a proliferative, synthetic state contributes to the formation of neointimal tissue during atherosclerosis and restenosis development and is related to SMC mechanical loading in vivo. The majority of past in vitro cell-stretching experiments have employed simplistic (uniform, uniaxial or biaxial) stretching environments to elucidate mechanobiological pathways involved in phenotypic shifts. However, the in vivo mechanics of the vascular wall consists of highly nonuniform stretch. Here we subjected 10T1/2 murine mesenchymal cells (an SMC precursor) to two- and three-dimensional nonuniform stretch environments. After 24 h of stretch, cells on an elastomeric membrane demonstrated varied proliferation [assessed by 5-bromo-2′-deoxyuridine (BrdU) incorporation] depending on location upon the membrane, with maximal proliferation occurring in a region of high, uniaxial stretch. Cells subjected to a nonuniform stretching regimen within three-dimensional polyethylene glycol diacrylate (PEGDA) hydrogel constructs demonstrated marked changes in mRNA expression of several phenotype-related proteins, indicating a sort of “hybrid” phenotype with contractile and synthetic markers being both upregulated and downregulated. Furthermore, expression levels of mRNAs were significantly different between various locations within the stretched gel. With the proliferation results, these data exhibit the capability of nonuniform stretching devices to induce heterogeneous cell responses, potentially indicative of spatial distributions of disease-related behaviors in vivo.

scholarly journals Elucidating the Molecular Mechanisms for the Interaction of Water with Polyethylene Glycol-Based Hydrogels: Influence of Ionic Strength and Gel Network Structure

Polymers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 845
Author(s):  
Xin Yang ◽  
Bronwin Dargaville ◽  
Dietmar Hutmacher
Keyword(s):  
Polyethylene Glycol ◽  
Ionic Strength ◽  
Molecular Mechanisms ◽  
Repeat Unit ◽  
Bound Water ◽  
Weight Fraction ◽  
Swelling Ratio ◽  
Polyethylene Glycol Diacrylate ◽  
Glycol Diacrylate ◽  
Hydrogel System

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.

scholarly journals Generation of Photopolymerized Microparticles Based on PEGDA Using Microfluidic Devices. Part 1. Initial Gelation Time and Mechanical Properties of the Material

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 ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Gelation Time ◽  
Mesh Size ◽  
Microfluidic Devices ◽  
Future Generation ◽  
Mechanical Tests ◽  
Continuous Systems ◽  
Polyethylene Glycol Diacrylate ◽  
Glycol Diacrylate ◽  
Close Relationship

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.

scholarly journals Fabrication of 3D-Printed Interpenetrating Hydrogel Scaffolds for Promoting Chondrogenic Differentiation

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2146
Author(s):  
Jian Guan ◽  
Fu-zhen Yuan ◽  
Zi-mu Mao ◽  
Hai-lin Zhu ◽  
Lin Lin ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Elastic Modulus ◽  
Chondrogenic Differentiation ◽  
Marker Genes ◽  
Self Healing ◽  
Polyethylene Glycol Diacrylate ◽  
3D Microenvironment ◽  
3D Printed

The limited self-healing ability of cartilage necessitates the application of alternative tissue engineering strategies for repairing the damaged tissue and restoring its normal function. Compared to conventional tissue engineering strategies, three-dimensional (3D) printing offers a greater potential for developing tissue-engineered scaffolds. Herein, we prepared a novel photocrosslinked printable cartilage ink comprising of polyethylene glycol diacrylate (PEGDA), gelatin methacryloyl (GelMA), and chondroitin sulfate methacrylate (CSMA). The PEGDA-GelMA-CSMA scaffolds possessed favorable compressive elastic modulus and degradation rate. In vitro experiments showed good adhesion, proliferation, and F-actin and chondrogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) on the scaffolds. When the CSMA concentration was increased, the compressive elastic modulus, GAG production, and expression of F-actin and cartilage-specific genes (COL2, ACAN, SOX9, PRG4) were significantly improved while the osteogenic marker genes of COL1 and ALP were decreased. The findings of the study indicate that the 3D-printed PEGDA-GelMA-CSMA scaffolds possessed not only adequate mechanical strength but also maintained a suitable 3D microenvironment for differentiation, proliferation, and extracellular matrix production of BMSCs, which suggested this customizable 3D-printed PEGDA-GelMA-CSMA scaffold may have great potential for cartilage repair and regeneration in vivo.

scholarly journals Shear Stress-Triggered Deformation of Microparticles in a Tapered Microchannel

Polymers ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 55
Author(s):  
Cheolheon Park ◽  
Junghyun Bae ◽  
Yeongjae Choi ◽  
Wook Park
Keyword(s):  
Shear Stress ◽  
Void Fraction ◽  
Applied Pressure ◽  
Microfluidic Channel ◽  
Volume Index ◽  
Effective Volume ◽  
Particle Deformation ◽  
Polyethylene Glycol Diacrylate ◽  
Glycol Diacrylate ◽  
Deformation Ratio

We demonstrate that it is possible to produce microparticles with high deformability while maintaining a high effective volume. For significant particle deformation, a particle must have a void region. The void fraction of the particle allows its deformation under shear stress. Owing to the importance of the void fraction in particle deformation, we defined an effective volume index (V*) that indicates the ratio of the particle’s total volume to the volumes of the void and material structures. We chose polyethylene glycol diacrylate (Mn ~ 700) for the fabrication of the microparticles and focused on the design of the particles rather than the intrinsic softness of the material (E). We fabricated microparticles with four distinct shapes: discotic, ring, horseshoe, and spiral, with various effective volume indexes. The microparticles were subjected to shear stress as they were pushed through a tapered microfluidic channel to measure their deformability. The deformation ratio R was introduced as R = 1−Wdeformed/Doriginal to compare the deformability of the microparticles. We measured the deformation ratio by increasing the applied pressure. The spiral-shaped microparticles showed a higher deformation ratio (0.901) than those of the other microparticles at the same effective volume index.

scholarly journals Patterning Vascular Networks In Vivo for Tissue Engineering Applications

2015 ◽  
Vol 21 (5) ◽  
pp. 509-517 ◽  
Author(s):  
Ritika R. Chaturvedi ◽  
Kelly R. Stevens ◽  
Ricardo D. Solorzano ◽  
Robert E. Schwartz ◽  
Jeroen Eyckmans ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Vascular Networks ◽  
Engineering Applications

Drug-eluting microneedles for self-administered treatment of keloids

TECHNOLOGY ◽  
2014 ◽  
Vol 02 (02) ◽  
pp. 144-152 ◽  
Author(s):  
Peng Xue ◽  
David Chen Loong Yeo ◽  
Yon Jin Chuah ◽  
Hong Liang Tey ◽  
Yuejun Kang ◽  
...  
Keyword(s):  
Clinical Supervision ◽  
Fibrous Tissue ◽  
Polyethylene Glycol Diacrylate ◽  
Glycol Diacrylate ◽  
Keloid Fibroblast ◽  
Culture Models ◽  
Drug Eluting ◽  
Good Potential ◽  
Microneedle Patch

Keloid is a long-term dermatological scarring disease characterized by disfiguring lesions resulting from overgrowth of dense fibrous tissue. Current therapeutics are ineffective, require clinical supervision and can be costly. This study investigated the use of microneedle technology in the self-management of keloid lesions. Specifically, a microneedle patch comprising of polyethylene glycol diacrylate (PEGDA) and encapsulating 5-fluorouracil (5-FU) has been developed for transdermal delivery. The microneedle patches showed requisite mechanical strength (hardness 45 ± 11 MPa, elastic modulus 0.66 ± 0.16 GPa) and were able to puncture porcine epidermis. The choice of PEGDA substrate enabled conformability to non-planar anatomical regions (e.g. elbow), with about 50% of the loaded 5-FU released during the first 12 hours. Thereafter, the microneedle efficacy was evaluated on in vitro keloid fibroblast culture models, where 5-FU loaded microneedles effectively abolished keloid fibroblast proliferation activity. In summary, we have developed a microneedle device with a good potential as an effective, economical and self-applied therapy for keloid scars.

scholarly journals Photo-Crosslinked Polymeric Matrix with Antimicrobial Functions for Excisional Wound Healing in Mice

Nanomaterials ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 791 ◽  
Author(s):  
Ming-Hsiang Chang ◽  
Yu-Ping Hsiao ◽  
Chia-Yen Hsu ◽  
Ping-Shan Lai
Keyword(s):  
Wound Healing ◽  
Wound Infection ◽  
Polymer Solution ◽  
Wound Dressing ◽  
Glycol Diacrylate ◽  
Excisional Wound ◽  
Poly Ethylene ◽  
Systemic Infections

Wound infection extends the duration of wound healing and also causes systemic infections such as sepsis, and, in severe cases, may lead to death. Early prevention of wound infection and its appropriate treatment are important. A photoreactive modified gelatin (GE-BTHE) was synthesized by gelatin and a conjugate formed from the 3,3′,4,4′-benzophenone tetracarboxylic dianhydride (BTDA) and the 2-hydroxyethyl methacrylate (HEMA). Herein, we investigated the photocurable polymer solution (GE-BTHE mixture) containing GE-BTHE, poly(ethylene glycol) diacrylate (PEGDA), chitosan, and methylene blue (MB), with antimicrobial functions and photodynamic antimicrobial chemotherapy for wound dressing. This photocurable polymer solution was found to have fast film-forming property attributed to the photochemical reaction between GE-BTHE and PEGDA, as well as the antibacterial activity in vitro attributed to the ingredients of chitosan and MB. Our in vivo results also demonstrated that untreated wounds after 3 days had the same scab level as the GE-BTHE mixture-treated wounds after 20 s of irradiation, which indicates that the irradiated GE-BTHE mixture can be quickly transferred into artificial scabs to protect wounds from an infection that can serve as a convenient excisional wound dressing with antibacterial efficacy. Therefore, it has the potential to treat nonhealing wounds, deep burns, diabetic ulcers and a variety of mucosal wounds.

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