Preparation and characterization of tunable oil-encapsulated alginate microfibers

A single-step microfluidic approach was developed which allowed a wide range of oil-loaded calcium-alginate microfibers to be fabricated at the same compositions but with different morphologies. A framework for characterization of wavy fibers was developed which linked the fiber morphology and tensile strength to the encapsulation type and geometry. The geometry of oil encapsulates as well as the fibers surface morphology were conveniently tuned via the gelation reaction dynamics and phase flow rates. A 2D mathematical reconstruction of the fiber's surface revealed that fibers having spherical and ellipsoid encapsulates enjoyed the highest surface roughness. Tubular fibers endured the highest tensile force before failure, compared to fibers with other encapsulate geometries at a fixed alginate phase ratio (ϕalg). Fibers with increased ϕalg withstood a higher tensile force. However, the strength of fibers reduced if the increase in ϕalg altered the encapsulate geometry from tubular to discrete oil segments. Tubular fibers also underwent maximum elastic and plastic deformation prior to failure, among all fibers.