All‐Aqueous Freeform Fabrication of Perfusable Self‐Standing Soft Compartments

Abstract

Compartmentalized structures obtained in all‐aqueous settings have shown promising properties as cell encapsulation devices, as well as reactors for trans‐membrane chemical reactions. While most approaches focus on the preparation of spherical devices, advances on the production of complex architectures have been enabled by the interfacial stability conferred by emulsion systems, namely mild aqueous two‐phase systems (ATPS), or non‐equilibrated analogues. However, the application of non‐spherical structures has mostly been reported while keeping the fabricated materials at a stable interface, limiting the free‐standing character, mobility and transposition of the obtained structures to different setups. Here, the fabrication of self‐standing, malleable and perfusable tubular systems through all‐aqueous interfacial assembly is shown, culminating in the preparation of independent objects with stability and homogeneity after disruption of the polymer‐based aqueous separating system. Those hollow structures can be fabricated with a variety of widths, and rapidly printed as long structures at flow rates of 15 mm s−1. The materials are used as compartments for cell culture, showcasing high cytocompatibility, and can be tailored to promote cell adhesion. Such structures may find application in fields that benefit from freeform tubular structures, including the biomedical field with, for example, cell encapsulation, and benchtop preparation of microfluidic devices.

Ionic Strength-Dependent Assembly of Polyelectrolyte-Nanoparticle Membranes via Interfacial Complexation at a Water–Water Interface

“…The growth of membrane fronts into one phase is commonly observed in ATPS-based interfacial membranes and has been attributed to the affinity of one or both complexing agents for a particular phase. 16,21 PDADMAC has been reported to have a slight preference for the PEG phase. 17 Moreover, strong partitioning of SiO 2 NP indicates that they also have a high affinity for the PEG phase (Figure S2).…”

“…While interfacial complexation of two oppositely charged polyelectrolytes (PE) in ATPS was first studied to prepare microcapsules, ,, this approach has since been exploited to generate tubular and multicompartmental structures attractive for multicompartment reactions and transport of species. ,, In principle, interfacial complexation in ATPS requires only that the components be charged and water-soluble, allowing tremendous flexibility in the selection of complexing materials and additional degrees of freedom in design of membrane functionality. For example, by simply swapping a PE for a nanoparticle (NP), complexed membranes can be formed with very different properties .…”

Toward Artificial Cell‐Mediated Tissue Engineering: A New Perspective

“…[29] Gonçalves et al, on the other hand, have focused on developing a new technique to be able to use bioink combinations that have been considered non-printable, by following a phase separation approach in liquid-liquid systems (Figure 3). [30] By benefiting from the phase separation between oppositely charged polymers, they managed to eliminate the necessity for structural support materials for non-printable combinations. Similarly, Zhang et al reported a method that re-quired a single droplet to start a light-based fabrication process within a polyacrylate-based resin environment, resulting in shortened production times.…”

Recent progress in fabrications and applications of functional hydrogel films

“…Another powerful postcrosslinking is through physical strategy, which has received increasing attention in recent years. 61 For example, we prepared tough metallosupramolecular hydrogel films by spin-coating of P(AAc-co-AAm) solutions and subsequent gelation in FeCl 3 solution to form robust carboxyl-Fe 3+ coordination complexes (Figure 2B). 56 The obtained hydrogel films showed excellent mechanical properties and tunable thickness by changing the polymer composition, spinning conditions, and polymer concentration.…”