Optimizing Green Light Photoredox Catalyzed Polymerizations for 3D Printing of Cell-Laden Hydrogels.

3D bioprinting is a powerful tool for fabricating complex tissue-like constructs, with digital light processing (DLP) offering exceptional speed and precision. However, conventional DLP relies on harmful UV light, limiting its application for cell-laden structures. Here, we developed green light-reactive photosystems for high-resolution hydrogel 3D printing.

Tunable hydrogel networks by varying secondary structures of hydrophilic peptoids provide viable 3D cell culture platforms for hMSCs.

Hydrogels have excellent ability to mimic the extracellular matrix (ECM) during 3D cell culture, yet it remains difficult to tune their mechanical properties without also changing network connectivity. Previously, we developed 2D culture platforms based on tunable hydrogels crosslinked by peptoids with various secondary structures: helical, non-helical, and unstructured, which allowed control over hydrogel mechanics independent of network connectivity. Here, we extend our strategy to 3D matrices by modifying the peptoids with piperazine and homopiperazine residues to enhance water solubility without altering their secondary structure.

Transcriptional regulation of living materials via extracellular electron transfer.

Engineered living materials combine the advantages of biological and synthetic systems by leveraging genetic and metabolic programming to control material-wide properties. Here, we demonstrate that extracellular electron transfer (EET), a microbial respiration process, can serve as a tunable bridge between live cell metabolism and synthetic material properties. In this system, EET flux from Shewanella oneidensis to a copper catalyst controls hydrogel cross-linking via two distinct chemistries to form living synthetic polymer networks.

Rapid hydrogel formation via tandem visible light photouncaging and bioorthogonal ligation.

The formation of benign polymer scaffolds in water using green-light-reactive photocages is described. These efforts pave an avenue toward the fabrication of synthetic scaffolds that can facilitate the study of cellular events for disease diagnosis and treatment. First, a series of boron dipyrromethene (BODIPY) photocages with nitrogen-containing nucleophiles were examined to determine structure-reactivity relationships, which resulted in a >1,000× increase in uncaging yield.

Tackling the tumor microenvironment - how can complex tumor models aid oncology drug development?

Introduction: Identifying effective cancer drugs remains an inefficient process. Drug efficacy in traditional preclinical cancer models translates poorly into therapy in the clinic. Implementation of preclinical models that incorporate the tumor microenvironment (TME) is needed to improve selection of active drugs prior to clinical trials.

A strategy to quantify myofibroblast activation on a continuous spectrum.

Myofibroblasts are a highly secretory and contractile cell phenotype that are predominant in wound healing and fibrotic disease. Traditionally, myofibroblasts are identified by the de novo expression and assembly of alpha-smooth muscle actin stress fibers, leading to a binary classification: "activated" or "quiescent (non-activated)". More recently, however, myofibroblast activation has been considered on a continuous spectrum, but there is no established method to quantify the position of a cell on this spectrum.