The extracellular matrix (ECM) forms through hierarchical assembly of small and larger polymeric molecules into a transient, hydrogel‐like fibrous network that provides mechanical support and biochemical cues to cells. Synthetic, fibrous supramolecular networks formed via non‐covalent assembly of various molecules are therefore potential candidates as synthetic mimics of the natural ECM, provided that functionalization with biochemical cues is effective. Here, combinations of slow and fast exchanging molecules that self‐assemble into supramolecular fibers are employed to form transient hydrogel networks with tunable dynamic behavior. Obtained results prove that modulating the ratio between these molecules dictates the extent of dynamic behavior of the hydrogels at both the molecular and the network level, which is proposed to enable effective incorporation of cell‐adhesive functionalities in these materials. Excitingly, the dynamic nature of the supramolecular components in this system can be conveniently employed to formulate multicomponent supramolecular hydrogels for easy culturing and encapsulation of single cells, spheroids, and organoids. Importantly, these findings highlight the significance of molecular design and exchange dynamics for the application of supramolecular hydrogels as synthetic ECM mimics.

A bis-urea biomaterial additive library was generated via a DoE approach. Comparison with a protein coating library revealed that simple catechol additives can replace a complex coating to create a living membrane for a bio-artificial kidney.

Human immune cells intrinsically exist as heterogenous populations. To understand cellular heterogeneity, both cell culture and analysis should be executed with single-cell resolution to eliminate juxtacrine and paracrine interactions, as these can lead to a homogenized cell response, obscuring unique cellular behavior. Droplet microfluidics has emerged as a potent tool to culture and stimulate single cells at high throughput. However, when studying adherent cells at single-cell level, it is imperative to provide a substrate for the cells to adhere to, as suspension culture conditions can negatively affect biological function and behavior. Therefore, we combined a droplet-based microfluidic platform with a thermo-reversible polyisocyanide (PIC) hydrogel, which allowed for robust droplet formation at low temperatures, whilst ensuring catalyzer-free droplet gelation and easy cell recovery after culture for downstream analysis. With this approach, we probed the heterogeneity of highly adherent human macrophages under both pro-inflammatory M1 and anti-inflammatory M2 polarization conditions. We showed that co-encapsulation of multiple cells enhanced cell polarization compared to single cells, indicating that cellular communication is a potent driver of macrophage polarization. Additionally, we highlight that culturing single macrophages in PIC hydrogel droplets displayed higher cell viability and enhanced M2 polarization compared to single macrophages cultured in suspension. Remarkably, combining phenotypical and functional analysis on single cultured macrophages revealed a subset of cells in a persistent M1 state, which were undetectable in conventional bulk cultures. Taken together, combining droplet-based microfluidics with hydrogels is a versatile and powerful tool to study the biological function of adherent cell types at single-cell resolution with high throughput.

A variety of biomedical applications requires tailored membranes; fabrication through a mix‐and‐match approach is simple and desired. Polymers based on supramolecular bis‐urea (BU) moieties are capable of modular integration through directed non‐covalent stacking. Here, it is proposed that non‐cell adhesive properties can be introduced in polycaprolactone‐BU‐based membranes by the addition of poly(ethylene glycol) (PEG)‐BU during immersion precipitation membrane fabrication, while unmodified PEG is not retained in the membrane. PEG‐BU addition results in denser membranes with a similar pore size compared to pristine membranes, while PEG addition induces defect formation. Infrared spectroscopy and surface hydrophobicity measurements indicate that PEG‐BU is retained during membrane processing. Additionally, PEG‐BU incorporation successfully leads to poor cell adhesive surfaces. No evidence is observed to indicate PEG retention. The results obtained indicate that the BU system enables intimate mixing of BU‐modified polymers after processing. Collectively, the results provide the first steps toward BU‐based immersion precipitated supramolecular membranes for biomedical applications.