For potential applications in the biomedical domain, we report a comprehensive roadmap towards structural hierarchy and anisotropy in electrospun fibers based on scattering and diffraction studies.

Infiltration of cells and their controlled spatial distribution within fibrous electrospun membranes is a challenging task but allows for the development of functional highly organized 3D hybrid tissues. Combining polymer electrospinning and cell electrospraying in a layer-by-layer approach is expected to overcome current limitations of reduced cell infiltration after traditional static seeding. However, organic solvents, used during the electrospinning process, impede often major issues due to their high cytotoxicity. Utilizing microfluidic encapsulation as a mean to embed cells within a protective polymer casing enables the controlled deposition of viable cells without interfering with the cellular phenotype. The presented techniques allow for novel cell manipulation approaches being significant for enhanced 3D tissue engineering based on its versatility in terms of material and cell selection.

Monitoring of ammonia in the human breath is of paramount importance to monitor diseases link to liver and kidney mulfunctioning. The present paper describes a solid-state optical ammonia sensor based on Förster resonance energy transfer (FRET) between narrowly dispersed blue-emitting carbon nanodots (CNDs) as FRET donor and fluorescein as FRET acceptor. The fluorophores were physically entrapped in a close to superhydrophobic sol-gel matrix, in turn deposited on a PVDF-HFP electrospun fiber membrane. The sensor shows a linear calibration with a remarkably low limit of detection, i.e., 110 ppb, and adequate reproducibility up to six N2/NH3 cycles.