Advanced Binary Guanosine and Guanosine 5'-Monophosphate Cell-Laden Hydrogels for Soft Tissue Reconstruction by 3D Bioprinting

Abstract

Soft tissue defects or pathologies frequently necessitate the use of biomaterials that provide the volume required for subsequent vascularization and tissue formation as autrografts are not always a feasible alternative. Supramolecular hydrogels represent promising candidates because of their 3D structure, which resembles the native extracellular matrix, and their capacity to entrap and sustain living cells. Guanosine-based hydrogels have emerged as prime candidates in recent years since the nucleoside self-assembles into well-ordered structures like G-quadruplexes by coordinating K + ions and π−π stacking, ultimately forming an extensive nanofibrillar network. However, such compositions were frequently inappropriate for 3D printing due to material spreading and low shape stability over time. Thus, the present work aimed to develop a binary cell-laden hydrogel capable of ensuring cell survival while providing enough stability to ensure scaffold biointegration during soft tissue reconstruction. For that purpose, a binary hydrogel made of guanosine and guanosine 5'monophosphate was optimized, rat mesenchymal stem cells were entrapped, and the composition was bioprinted. To further increase stability, the printed structure was coated with hyperbranched polyethylenimine. Scanning electron microscopic studies demonstrated an extensive nanofibrillar network, indicating excellent G-quadruplex formation, and rheological analysis confirmed good printing and thixotropic qualities. Additionally, diffusion tests using fluorescein isothiocyanate labeled-dextran (70, 500, and 2000 kDa) showed that nutrients of various molecular weights may diffuse through the hydrogel scaffold. Finally, cells were evenly distributed throughout the printed scaffold, cell survival was 85% after 21 days, and lipid droplet formation was observed after 7 days under adipogenic conditions, indicating successful differentiation and proper cell functioning. To conclude, such hydrogels may enable the 3D bioprinting of customized scaffolds perfectly matching the respective soft tissue defect, thereby potentially improving the outcome of the tissue reconstruction intervention.

Mechanical, robust and conductive eco-friendly self-assembling hydrogel: a novel material for electromagnetic shielding

“…The size of the sample is dumbbell-shaped (tensile) or cylindrical (compression). 46,47 The four-probe tester (RK-YA, China) is a commonly used device for conductivity measurements, and is commissioned at 5 V with a spacing of 2.35 mm between each stylus, according to national standards. Samples are first cut into rectangular strips 10 mm long, 3.5 mm wide, and 1 mm thick, and then tested at room temperature, at least three times for each sample.…”

“…Samples are first cut into rectangular strips 10 mm long, 3.5 mm wide, and 1 mm thick, and then tested at room temperature, at least three times for each sample. 47,48 The EMI test instrument used is a vector network analyzer (N5225B, Keysight, China), and the test sample size is of length 10 mm, width 3.5 mm, and thickness 1 mm. The real ( ε ′) and imaginary ( ε ′′) parts of the dielectric constant of the sample in the X-band (8.2–12.4 GHz) are first tested and then analyzed and calculated.…”

Dancing with Nucleobases: Unveiling the Self-Assembly Properties of DNA and RNA Base-Containing Molecules for Gel Formation

“…Overall, modified oligonucleotides enable the creation of self-assembling materials with tailored properties and enhanced stability. As for the importance of the nucleobase's nature in the gel formation process, certain guanine derivatives and, particularly, guanosine-based small molecules and polymers have been explored for their ability to form guanosine-containing supramolecular structures and gels through hydrogen bonding and π-π stacking interactions [21][22][23][24]. Apart from the oligomeric structures of DNA and their analogs, the monomeric nucleosides or nucleotides modified with non-natural bases, including fluorinated nucleosides or other base analogs, or sugar modifications have also been explored for their gel-forming properties [25][26][27][28].…”

Guanosine-Based Multidrug Strategy Delivery for Synergistic Anti-Inflammation

“…Degradation assays in vitro in various conditions were evaluated due to the material residues, which could result in terrible foreign-body reactions Figure A displayed the results of the removal, freeze-drying, and weighing of the leftover hydrogel at the measured time intervals.…”