Lysozyme-Responsive Spray-Dried Chitosan Particles for Early Detection of Wound Infection

Infections are a severe health issue, and the need for an early point-of-care diagnostic approach for wound infections is continuously growing. Lysozyme has shown a great potential as a biomarker for rapid detection of wound infection. In this study, spray-drying of labeled and derivatized chitosans was investigated for the production of small particles responsive to lysozyme. Therefore, various chitosans, differing in their origin (snow crab, Chionoecetes sp. , with medium and low molecular weight or shrimp) were N -acetylated, labeled with reactive black 5, and tested for solubility and spray-drying suitability. Reactive black-5-stained N -acetylated chitosan (low molecular weight, origin crab) was successfully spray-dried, and the obtained particles were characterized regarding size, ζ potential, and morphology. The particles showed an average hydrodynamic radius of 612.5 ± 132.8 nm. ζ potential was measured in the context of a later application as an infection detection system for wound infections in artificial wound fluid (-6.14 ± 0.16 mV) and infected wound fluid (-7.93 ± 1.35 mV). Furthermore, the aggregation behavior and surface structure were analyzed by using scanning electron microscopy and confocal laser scanning microscopy revealing spherical-shaped particles with explicit surface topologies. Spray-dried N -acetylated chitosan particles showed a 5-fold increase in lysozyme-responsive release of dyed chitosan fragments due to the enhanced surface area to volume ratio when compared to non-spray-dried N -acetylated chitosan flakes. On the basis of these results, the study showed the improved properties of N -acetylated spray-dried chitosan particles for future applications for early and rapid infection detection.