Precision cell delivery in biphasic polymer systems enhances growth of keratinocytes in culture and promotes their attachment on acellular dermal matrices

Abstract

Current approaches for precision deposition of cells are not optimized for moist environments or for substrates with complex surface topographic features, for example, the surface of dermal matrices and other biomaterials. To overcome these challenges, an approach is presented that utilizes cell confinement in phase‐separating polymer solutions of polyethylene glycol and dextran to precisely deliver keratinocytes in well‐defined colonies. Using this approach, keratinocyte colonies are produced with superior viability, proliferative capacity, and barrier formation compared with the same number of cells dispersedly seeded across substrate surfaces. It is further demonstrated that keratinocytes delivered in colonies to the surface of acellular dermal matrices form an intact epidermal basal layer more rapidly and more completely than cells delivered by conventional dispersed seeding. These findings demonstrate that delivery of keratinocytes in phase‐separating polymer solutions holds potential for enhancing growth of keratinocytes in culture and production of functional skin equivalents.

Nonspecific characteristics of macromolecules create specific effects in living cells

“…Moderate crowding generated by dextran in the exterior provides an opportunity for rearrangement through which cell-cell association in the assembly can be reinforced. For highly organized cell spheroids, droplets in ATPSs are good containers for culturing cells (Atefi et al 2015;Han et al 2015;Agarwal et al 2019). Interestingly, without external manipulation, and instead by simply adjusting the PEG/DEX ratio, it is possible to modulate the arrangement of cells in microdroplets (Fig.…”

Characterization of polymer‐polymer aqueous two‐phase system droplets for 3D culture future applications

“…Their main advantage is that they can be rapidly adapted to any research focused on droplet generation saving complex and laborious procedures. Furthermore, the specific cell patterns generated in ATPS‐3D are influenced mainly by the geometry of ATPS droplets 11,28 . These ATPS droplets play the role of determining the size and shape of adherent cell colonies based on the dispersity, self‐assembly and adherence of cells within the ATPS droplet.…”

“…Furthermore, the specific cell patterns generated in ATPS-3D are influenced mainly by the geometry of ATPS droplets. 11,28 These ATPS droplets play the role of determining the size and shape of adherent cell colonies based on the dispersity, self-assembly and adherence of cells within the ATPS droplet. Therefore, the characterization of ATPS droplets remains crucial as a step before cell encapsulation in ATPS-3D.…”

Microfluidic Control of Coexisting Chemical Microenvironments within Multiphase Water-in-Fluorocarbon Droplets

“…The physical chemistry governing bulk aqueous phase separation has been explored for decades, particularly as a means of using neutral polymer or polymer/salt aqueous two phase systems (ATPS) in biological separations, as included solutes typically demonstrate preferential partitioning among the phases present. − Given an arbitrary two phase system, a phase diagram maps the total polymer compositions that result in either single phase or phase-separated solutions. For any composition within the phase-separated region, there exists a tie line connecting it to two points on the binodal line, which give the polymer composition of the individual phases (Figure B). ,,, The tie line length (TLL) reflects the disparity in composition between the two phases; longer tie lines indicate more distinct phases, and lead to stronger solute partitioning. ,,− Solute localization within distinct coexisting aqueous phases, both as a bulk system and as droplets, has been extensively studied for use in applications such as biomolecular purification and extraction, ,− bioengineering, ,− modeling of membraneless organelles, ,− and reactant localization. − , Such phase-separated systems have also been studied in the form of emulsions, recently in conjunction with microfluidic technologies, resulting in the production of both all-aqueous ,,,− and water-in-oil − emulsions with controllable morphologies, surface chemistry, and encapsulated components. However, while TLL has long been used as a means of controlling local solute concentration within bulk ATPS, ,,,,, such efforts have generally not been undertaken for droplet-based systems, due to the difficulty in selecting specific phase compositions on an individual droplet level.…”