Freeform, Reconfigurable Embedded Printing of All‐Aqueous 3D Architectures

Abstract

Aqueous microstructures are challenging to create, handle, and preserve since their surfaces tend to shrink into spherical shapes with minimum surface areas. The creation of freeform aqueous architectures will significantly advance the bioprinting of complex tissue‐like constructs, such as arteries, urinary catheters, and tracheae. The generation of complex, freeform, three‐dimensional (3D) all‐liquid architectures using formulated aqueous two‐phase systems (ATPSs) is demonstrated. These all‐liquid microconstructs are formed by printing aqueous bioinks in an immiscible aqueous environment, which functions as a biocompatible support and pregel solution. By exploiting the hydrogen bonding interaction between polymers in ATPS, the printed aqueous‐in‐aqueous reconfigurable 3D architectures can be stabilized for weeks by the noncovalent membrane at the interface. Different cells can be separately combined with compartmentalized bioinks and matrices to obtain tailor‐designed microconstructs with perfusable vascular networks. The freeform, reconfigurable embedded printing of all‐liquid architectures by ATPSs offers unique opportunities and powerful tools since limitless formulations can be designed from among a breadth of natural and synthetic hydrophilic polymers to mimic tissues. This printing approach may be useful to engineer biomimetic, dynamic tissue‐like constructs for potential applications in drug screening, in vitro tissue models, and regenerative medicine.

Non-associative phase separation in an evaporating droplet as a model for prebiotic compartmentalization

“…58 This provides great potential for various droplet-based bioinspired techniques in our model system. [59][60][61][62] Summarizing, our results present a robust NES for non-associative phase separation inside a sessile droplet. Due to the highly non-uniform evaporation flux, phase separation is triggered at the rim of the sessile droplet, exhibiting a self-organized pattern decided by both original composition and the concentration change due to the water loss, as demonstrated by the kinetic pathway of phase separation.…”

An open-source handheld extruder loaded with pore-forming bioink for in situ wound dressing

“…the aqueous two-phase emulsion system, when the two aqueous phases used are meticulously selected [ 41 , 42 ]. As such, it has been demonstrated that it was possible to directly write [ 43 ] or print [ 44 ] an aqueous pattern within another aqueous bath, or produce droplets using microfluidic devices [ [45] , [46] , [47] , [48] , [49] ]. The unique advantage of biocompatibility of the aqueous two-phase emulsion system allows it to be used in the presence of cells without exerting any toxicity otherwise imposed by the organic solvents in conventional emulsions.…”

Perspective: Ferromagnetic Liquids

“…A multi-responsive structured liquid system can be used to dynamically control droplet reactors [10]. It should be noted that the interfacial formation and jamming of the nanoparticle surfactants is not constrained to oil/water systems, aqueous/aqueous and oil/oil systems are possible (Figure 1e) [4,32].…”