Protocol for the synthesis and activation of hydrogels with photocaged oligonucleotides.

Hydrogels with spatial-temporal control over chemical and physical properties allow for the creation of cellular niches with controllable properties that better mimic tissue environments. Here, we present a protocol for synthesizing hydrogels incorporating photocaged oligonucleotides that can be activated with non-ultraviolet (UV) wavelengths. We detail the synthesis of bulk hydrogels and spatially defined hydrogels with different chemical functionalities that all share common photocaged DNA.

Targeting nanoparticles to lung cancer-derived A549 cells based on changes on interstitial stiffness in biomimetic models.

The mechanical properties and forces of the extracellular environment modulate alveolar epithelial cell behavior. To model cancer/fibrosis associated stiffening and dynamic stretch, a biomimetic device was developed that imitates the active forces in the alveolus, while allowing control over the interstitial matrix stiffness. Alveolar epithelial A549 cancer cells were cultured on the devices and their transcriptome was profiled with RNA sequencing.

Controlling Cell Interactions with DNA Directed Assembly.

The creation of complex cellular environments is critical to mimicking tissue environments that will play a critical role in next-generation tissue engineering, stem cell programming, and therapeutic screening. To address this growing need, techniques capable of manipulating cell-cell and cell-material interactions are required that span single-cell to 3D tissue architectures. DNA programmed assembly and placement of cells present a powerful technique for the bottom-up synthesis of living microtissues for probing key questions in cell-cell and cell-material-driven behaviors through its refined control over placement and architecture.

Multifunctional hydrogels with spatially controlled light activation with photocaged oligonucleotides.

Recreating tissue environments with precise control over mechanical, biochemical, and cellular organization is essential for next-generation tissue models for drug discovery, development studies, and the replication of disease environments. However, controlling these properties at cell-scale lengths remains challenging. Here, we report the development of printing approaches that leverage polyethylene glycol diacrylate (PEGDA) hydrogels containing photocaged oligonucleotides to spatially program material characteristics with non-destructive, non-ultraviolet light.

Light-Controlled Cell-Cell Assembly Using Photocaged Oligonucleotides.

The interactions between heterogeneous cell populations play important roles in dictating various cell behaviors. Cell-cell contact mediates communication through the exchange of signaling molecules, electrical coupling, and direct membrane-linked ligand-receptor interactions. In vitro culturing of multiple cell types with control over their specific arrangement is difficult, especially in three-dimensional (3D) systems.

Nanoparticle targeting of mechanically modulated glycocalyx.

The mechanical properties and forces in the extracellular environment surrounding alveolar epithelial cells have the potential to modulate their behavior. Particularly, breathing applies 3-dimensional cyclic stretches to the cells, while the stiffness of the interstitium changes in disease states, such as fibrosis and cancer. A platform was developed that effectively imitates the active forces in the alveolus, while allowing one to control the interstitium matrix stiffnesses to mimic fibrotic lung tumor microenvironments.