Rheolution's Resources in Life Sciences

Exploring the frontier of 3D printing, Cornell University researchers have enhanced the Freeform Reversible Embedding of Suspended Hydrogels (FRESH) method. They introduced a computational approach for non-planar printing, enabling complex curved structures, improving printing accuracy and augmenting the mechanical properties of bioprints.

Researchers at the DWI – Leibniz-Institute for Interactive Materials, Aachen, Germany have developed injectable microgels that can be magnetically oriented within a larger hydrogel to regenerate various types of tissue. The team began by functionalizing a material called six-arm poly(ethylene oxide-stat-propylene oxide) with acrylate groups, which can be broken down and removed by the kidney. Superparamagnetic iron oxide nanoparticles, which can align to an applied magnetic field, were mixed into the functionalized material. The team then crosslinked this mixture with UV-light to form microgels. To increase the contact surface with cells, a peptide containing the RGD sequence, a focal adhesion point for cells, was grafted onto the microgels. This innovative strategy provides a promising tool for tissue regeneration.

The development of tissue engineering products faces challenges due to the variety of biomaterials available and their dynamic properties once implanted. A recent study used artificial intelligence (AI) to help address this problem. The researchers created a system that automates the prediction of gelation time (when a liquid solution becomes a hydrogel) for different formulations. The hydrogels were composed of silk, horseradish peroxidase (HRP), hydrogen peroxide, and bacterial cells. They utilized differential dynamic microscopy (DDM) to identify gelation time and machine learning (ML) to predict the gelation time of different hydrogel compositions. This allowed them to streamline the process of finding hydrogel formulations with specific properties.

4D-bioprinting introduces "time" into the printing process, allowing printed structures to evolve. Researchers from the University of Illinois Chicago used oxidized and methacrylated alginate (OMA) to develop a bioink for 4D bioprinting. They made OMA into precursor beads, then transformed them into a "microgel" that could be easily printed into stable 3D constructs. Mixed with cells, the microgel became a bioink, which was printed into complex structures. The printed constructs could be further crosslinked to create 3D scaffolds that could change shape due to differential swelling, adding the 4th dimension, "time," to the printing process.

Recent advancements in 3D-bioprinting have opened the possibility of creating engineered tissues mimicking human native tissues. However, reproducing the extracellular matrix (ECM) composition and microscopic architecture within the biomaterial ink remains challenging. To tackle this, a research group from the AO Research Institute Davos developed a bioink containing both collagen type 1 and tyramine derivative hyaluronan for tissue engineering. They used optimal concentrations of these two components, along with human bone marrow-derived mesenchymal stromal cells. Two crosslinking pathways were used to induce gelation and create a 3D scaffold that was then printed using the bioink's shear-thinning properties. They successfully printed an anisotropic hydrogel, achieving control over the microscopic organization of the matrix. This breakthrough could pave the way for better mimicry of native human tissues, especially anisotropic ones, in tissue engineering applications.

Scientists from Dalhousie University, led by Dr. Mark Joseph Filiaggi, investigated the sodium polyphosphate (NaPP) polymer as a potential hemostatic agent. They tested six formulations of the biomaterial, with varying degrees of polymerization and types of divalent cations. The hemostatic potential of these formulations was evaluated using various blood clotting assays. The biomaterial was mixed with coagulation reagents and recalcified blood or plasma in a tube, which was then shaken to visually assess blood or plasma flow. The clotting time was noted as the time required to achieve no flow. Surgifoam®, a commercial hemostatic agent, was used as a control.