Melt-electrowriting with novel milk protein/PCL biomaterials for skin regeneration

Abstract

Demand for skin replacements is rapidly increasing as burn and full-thickness wounds are difficult to repair due to the low regeneration capability of innate tissues, as well as the physical drawbacks associated with currently available substitutes. To address this need, an emerging 3D printing technique, melt-electrowriting (MEW) was used to create novel bioactive scaffolds to promote skin regeneration. Polycaprolactone (PCL), a bioresorbable and biocompatible, synthetic polymer with Food and Drug Administration approval for use in the human body was selected as scaffold material due to its mechanical stability, flexibility, and superior melt processing properties. In order to increase PCL’s biological functionality bioactive milk proteins (MPs) were blended with PCL. To date, this is the first study of its kind detailing the tissue regenerative capacity of PCL containing MPs as bioactive additives for skin regeneration using MEW. The aim of this study was to MEW MP/PCL tissue engineered constructs (TEC) and assess their suitability for generating tissue in vitro. The MPs, lactoferrin (LF) and whey protein (WP), were mixed with PCL individually at varying concentrations (0.05%, 0.1%, 0.25%), and in combination (COMB) at concentrations of 0.25% each. TECs were characterised chemically, physically, and their biological activity assessed in vitro. Physical characterisation of MEW MP/PCL scaffolds showed that reproducible, layered micron range scaffolds could be fabricated; displaying high porosity, low degradation, and rapid protein release. Biological activity, determined via an in vitro skin model using human keratinocytes (HaCaTs) and normal human dermal fibroblasts cells, showed significantly increased cell growth, spreading, and infiltration into LF (0.25%) containing scaffolds and COMB scaffolds when compared to PCL alone (p ≤ 0.05). These findings demonstrated that the combined addition of LF and WP increased the biological activity of MEW PCL scaffolds and could be potentially used as a TEC for deep tissue dermal regeneration.

Polymers for Melt Electrowriting

“…PCL is a semicrystalline, biodegradable polyester that is readily processable via MEW due to its low melting temperature [5,27] and rapid solidification. [28] It is favorable from the biomedical perspective as it is approved by the U.S. Food and Drug Administration (FDA) for certain clinical purposes [29] and offers a slow degradation rate up to several years. [18,27,30] PCL is also wellstudied in biomedical engineering as part of many other manufacturing technologies, such as SES, phase separation, and dipcoating.…”

“…M w = 45.6 × 10 3 [ 67,68] M w = 50 kDa [64] [ 5,67,68,64,15] Capa 6500C High clarity grade when molten M w = 50 × 10 3 a) [69] MFI = 7 b) [ 69,70] Capa 6506 Medical grade M w = 50 kDa [29] [29]…”

A mini review on the generation of crimped ultrathin fibers via electrospinning: Materials, strategies, and applications

“…On the other hand, when MEW is performed at collector speeds that are lower than the electrified jet speed, a buckling phenomenon of the jet occurs, similar to a column of honey falling onto toast . This technique allows such design principles for manufacturing new and orderly microstructures …”

3D Printing of Metal/Metal Oxide Incorporated Thermoplastic Nanocomposites With Antimicrobial Properties

“…and melt electrowriting (MEW) can also be used to print the thermoplastic nanocomposites (Hewitt et al, 2019;Nonato et al, 2019). However, regardless of the printing approach and method of nanocomposite preparation much research remains to be done.…”

“…In final step the polymerization is effectuated by UV or other light sources ( Weng et al, 2016 ). In addition, liquid deposition molding (LDM), solvent-cast 3D printing (SCP) and melt electrowriting (MEW) can also be used to print the thermoplastic nanocomposites ( Hewitt et al, 2019 ; Nonato et al, 2019 ). However, regardless of the printing approach and method of nanocomposite preparation much research remains to be done.…”