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Objective: Decellularizing solid organs is a promising top-down process to produce acellular bio-scaffolds for ‘de novo’ regrowth or application as tissue ‘patches’ that compensate, e.g., large volumetric muscle loss in reconstructive surgery. Therefore, generating standardized acellular muscle scaffolds marks a pressing area of need. Although animal muscle decellularization protocols were established, those are mostly manually performed and lack defined bioreactor environments and metrologies to assess decellularization quality in real-time. To close this gap, we engineered an automated bioreactor system to provide chemical decellularization solutions to immersed whole rat gastrocnemius medialis muscle through perfusion of the main feeding arteries. Results: Perfusion control is adjustable according to decellularization quality feedback. This was assessed both from (i) ex situ assessment of sarcomeres/nuclei through multiphoton fluorescence and label-free Second Harmonic Generation microscopy and DNA quantification, along with (ii) in situ within the bioreactor environment assessment of the sample’s passive mechanical elasticity. Conclusion: We find DNA and sarcomere-free constructs after 72 h of 0.1% SDS perfusion-decellularization. Furthermore, passive elasticity can be implemented as additional online decellularization quality measure, noting a threefold elasticity decrease in acellular constructs. Significance: Our MyoBio represents a novel and useful automated bioreactor environment for standardized and controlled generation of acellular whole muscle scaffolds as a valuable source for regenerative medicine. [ABSTRACT FROM AUTHOR]

Biomimetically designed medical-grade polycaprolactone (mPCL) dressings are 3D-printed with pore architecture and anisotropic mechanical characteristics that favor skin wound healing with reduced scarring. Melt electrowritten mPCL dressings are seeded with human gingival tissue multipotent mesenchymal stem/stromal cells and cryopreserved using a clinically approved method. The regenerative potential of fresh or frozen cell-seeded mPCL dressing is compared in a splinted full-thickness excisional wound in a rat model over six weeks. The application of 3D-printed mPCL dressings decreased wound contracture and significantly improved skin regeneration through granulation and re-epithelialization compared to control groups. Combining 3D-printed biomimetic wound dressings and precursor cell delivery enhances physiological wound closure with reduced scar tissue formation. Image 1 [ABSTRACT FROM AUTHOR]