**4. Conclusions**

Scaffolds entirely based on polysaccharides (pullulan and chitosan plus chondroitin sulfate or hyaluronic acid) were manufactured by means of electrospinning and norfloxacin was loaded as a free drug or as nanocomposite of montmorillonite. The scaffolds were characterized by their homogeneous structures, with fibers of 500 nm diameter when norfloxacin was loaded as a free drug, independent of drug concentration. On the contrary, the presence of nanocomposite caused a certain degree of surface roughness of the fibers with 1000 nm diameters, dramatically influenced by drug concentration. Moreover, this altered entanglement of polymer chains in the scaffolds and caused higher deformability and lower elasticity, compared to the scaffolds loaded with norfloxacin as a free drug, and decreased the mechanical resistance of the systems. The hydration of the scaffolds changed their mechanical properties and the scaffolds were more prone to deformation. This is an advantageous feature, considering their implantation in lesions. Moreover, scaffold degradation occurring via lysozyme secreted during the inflammatory phase of the healing process should ensure scaffold resorption and, simultaneously, drug release. All the scaffolds proved to be degraded via lysozyme and this sustained the drug release (from 50% to 100% in 3 days, depending on system composition), especially when the drug was loaded in the scaffolds as a nanocomposite at 1%. Moreover, the scaffolds were able to decrease the bioburden by at least 100-fold, proving that drug loading in the scaffolds did not impair the antimicrobial activity of norfloxacin. Chondroitin sulfate and montmorillonite in the scaffolds proved to possess a synergic performance in enhancing the fibroblast proliferation without impairing norfloxacin antimicrobial properties. The scaffold based on chondroitin sulfate and containing 1% norfloxacin in nanocomposite was demonstrated to possess adequate stiffness to support fibroblast proliferation and the capability to sustain antimicrobial properties to prevent/treat nonhealing wound infection during the healing process.

## **5. Patents**

Sandri, G., Bonferoni, M.C., Rossi, S., Ferrari, F., electrospun nanofibers and membranes, PCT/ IT2017/000160, 2017.

**Supplementary Materials:** The following are available online at http://www.mdpi.com/1999-4923/12/4/325/s1, Figure S1: FTIR spectra of all the components of the scaffolds, Figure S2: XRPD spectra of the components of the scaffolds presenting signals, Figure S3: Thermal analysis (TGA and DSC) of the components and the scaffolds containing the nanocomposite.

**Author Contributions:** Conceptualization, G.S.; methodology, G.S.; software, F.F. and M.C.B.; validation, C.V.; investigation, P.G., A.F., M.R.; B.V.; D.M.; data curation, C.A., G.S.; writing—original draft preparation, G.S., M.R., A.F.; writing—review and editing, G.S.; supervision, G.S.; project administration, G.S.; funding acquisition, C.V., G.S., S.R., F.F., M.C.B. All authors have read and agreed to the published version of the manuscript.

**Funding:** This work was partially supported by Horizon 2020 Research and Innovation Programme under Grant Agreement No 814607.

**Acknowledgments:** The authors wish to thank Giusto Faravelli SpA for suppling the polymers.

**Conflicts of Interest:** The authors declare no conflict of interest.
