A Granular Hydrogel-Enabled Wearable Electrochemical Biosensing Platform for Continuous Non-Invasive Sweat Lactate Detection.

Although continuous and non-invasive measurements of sweat biomarkers may provide vital health information, sweat collection often involves intense physical activities or chemical/thermal stimuli. The natural body sweat during endogenous metabolic or stress processes, secreted at much lower rates at rest, may be continuously analyzed using microfluidic devices integrated with hydrophilic rigid fillers; however, the sweat uptake and accumulation in thermoregulatory processes take too long for near-real-time measurements. This work provides an innovative body fluid collection strategy using a granular hydrogel scaffold (GHS), facilitating osmotic and capillary effects to uptake and transfer an ultralow amount of sweat into a microfluidic device at rest.

Generalizing Gelatin Methacryloyl Granular Hydrogel Fabrication Using Stable Microgels with Predictable Stiffness.

Gelatin methacryloyl (GelMA) granular hydrogel scaffolds (GHS) outperform their bulk, nanoporous hydrogel counterparts in regenerative engineering as a result of cell-scale tunable interconnected void spaces among assembled microgel building blocks. Conventional GelMA GHS fabrication is based on jamming physically crosslinked GelMA microgels below the sol-gel transition temperature, followed by chemical crosslinking to form inter- and intra-microgel covalent bonds. Thus, the in situ formation of GelMA GHS on tissues is impaired by the phase transition (dissolution) of physically crosslinked microgels at the physiological temperature.

Gelatin methacryloyl granular hydrogel scaffolds for skin wound healing.

The pore size and structure of hydrogel scaffolds play a key role in regulating host-scaffold interactions. Incorporating macropores within bulk hydrogels may increase cell ingrowth and modulate scaffold-induced inflammation. To this end, granular hydrogel scaffolds (GHS) have been developed assembling hydrogel microparticles (microgels).

Engineering Microgel Packing to Tailor the Physical and Biological Properties of Gelatin Methacryloyl Granular Hydrogel Scaffolds.

Granular hydrogel scaffolds (GHS) are fabricated via placing hydrogel microparticles (HMP) in close contact (packing), followed by physical and/or chemical interparticle bond formation. Gelatin methacryloyl (GelMA) GHS have recently emerged as a promising platform for biomedical applications; however, little is known about how the packing of building blocks, physically crosslinked soft GelMA HMP, affects the physical (pore microarchitecture and mechanical/rheological properties) and biological (in vitro and in vivo) attributes of GHS. Here, the GHS pore microarchitecture is engineered via the external (centrifugal) force-induced packing and deformation of GelMA HMP to regulate GHS mechanical and rheological properties, as well as biological responses in vitro and in vivo.

Multifunctional self-healing hydrogels via nanoengineering of colloidal and polymeric cellulose.

The unique features of self-healing hydrogels hold great potential for biomedical applications including injectable hydrogels for cancer treatment, procedures for tumor removal or resection. However, the fabrication of durable and multifunctional self-healing hydrogels composed of biocompatible, green building blocks via versatile synthetic methodology continues to pose a significant challenge. Here, we engineered dialdehyde cellulose (DAC, as a macromolecular bio-crosslinker), and electrosterically stabilized nanocrystalline cellulose (ENCC, as a ligand-targeted drug carrier) to facilitate a strategy for the construction of self-healing hydrogels.

Iron inhibits glioblastoma cell migration and polarization.

Glioblastoma is one of the deadliest malignancies facing modern oncology today. The ability of glioblastoma cells to diffusely spread into neighboring healthy brain makes complete surgical resection nearly impossible and contributes to the recurrent disease faced by most patients. Although research into the impact of iron on glioblastoma has addressed proliferation, there has been little investigation into how cellular iron impacts the ability of glioblastoma cells to migrate-a key question, especially in the context of the diffuse spread observed in these tumors.

Accelerating Patterned Vascularization Using Granular Hydrogel Scaffolds and Surgical Micropuncture.

Bulk hydrogel scaffolds are common in reconstructive surgery. They allow for the staged repair of soft tissue loss by providing a base for revascularization. Unfortunately, they are limited by both slow and random vascularization, which may manifest as treatment failure or suboptimal repair.

Dynein-Powered Cell Locomotion Guides Metastasis of Breast Cancer.

The principal cause of death in cancer patients is metastasis, which remains an unresolved problem. Conventionally, metastatic dissemination is linked to actomyosin-driven cell locomotion. However, the locomotion of cancer cells often does not strictly line up with the measured actomyosin forces.

Dynein-Powered Cell Locomotion Guides Metastasis of Breast Cancer.

Metastasis is a principal cause of death in cancer patients, which remains an unresolved fundamental and clinical problem. Conventionally, metastatic dissemination is linked to the actomyosin-driven cell locomotion. However, locomotion of cancer cells often does not strictly line up with the measured actomyosin forces.

Gelatin Methacryloyl Granular Hydrogel Scaffolds: High-throughput Microgel Fabrication, Lyophilization, Chemical Assembly, and 3D Bioprinting.

The emergence of granular hydrogel scaffolds (GHS), fabricated via assembling hydrogel microparticles (HMPs), has enabled microporous scaffold formation in situ. Unlike conventional bulk hydrogels, interconnected microscale pores in GHS facilitate degradation-independent cell infiltration as well as oxygen, nutrient, and cellular byproduct transfer. Methacryloyl-modified gelatin (GelMA), a (photo)chemically crosslinkable, protein-based biopolymer containing cell adhesive and biodegradable moieties, has widely been used as a cell-responsive/instructive biomaterial.

Nanoengineered Granular Hydrogel Bioinks with Preserved Interconnected Microporosity for Extrusion Bioprinting.

3D bioprinting of granular hydrogels comprising discrete hydrogel microparticles (microgels) may overcome the intrinsic structural limitations of bulk (nanoporous) hydrogel bioinks, enabling the fabrication of modular thick tissue constructs. The additive manufacturing of granular scaffolds has predominantly relied on highly jammed microgels to render the particulate suspensions shear yielding and extrudable. This inevitably compromises void spaces between microgels (microporosity), defeating rapid cell penetration, facile metabolite and oxygen transfer, and cell viability.

3D bioprinting for reconstituting the cancer microenvironment.

The cancer microenvironment is known for its complexity, both in its content as well as its dynamic nature, which is difficult to study using two-dimensional (2D) cell culture models. Several advances in tissue engineering have allowed more physiologically relevant three-dimensional (3D) in vitro cancer models, such as spheroid cultures, biopolymer scaffolds, and cancer-on-a-chip devices. Although these models serve as powerful tools for dissecting the roles of various biochemical and biophysical cues in carcinoma initiation and progression, they lack the ability to control the organization of multiple cell types in a complex dynamic 3D architecture.