A novel fiber dressing was fabricated by blending nano-silica or hydroxyapatite with alginate via microfluidic spinning, which demonstrated delayed degradation, greater mechanical performance and superior bioactivity due to the reinforcing alginate fibers. The prepared fibrous dressings exhibited higher surface area and porosity, which was conducive to cell growth. The addition of nano-silica and hydroxyapatite particles in the alginates improved the mechanical properties and biomineralization on the surface of the fibers. Besides, the degradation time scale and swelling behavior of the nanoparticle reinforced alginate fibers were delayed compared to the original alginate fibers, indicating a longer duration in contact with the wound. The prompt proliferation of fibroblast and keratinocyte cells suggested no significant cytotoxicity of the alginate containing silica and hydroxyapatite. Taken together, porous alginate fibers reinforced by nano-silica and/or hydroxyapatite showed high potential for wound dressing applications.