Microfluidic-assisted manufacture of chemically-modified silk nanoparticles

• Κύριος συγγραφέας: Rezwan, Refaya
• Άλλοι συγγραφείς: Κλεπετσάνης, Παύλος
• Μορφή: Thesis
• Γλώσσα: English
• Έκδοση: 2020
• Θέματα: Nanoparticles; Silk; Chemical modification; Νανοσωματίδια; Μετάξι; Χημική τροποποίηση

Silk has gained renewed interest now as a drug delivery system. Liquid silk fibroin can be processed into many drug delivery systems, including nanoscale particles. Desolvation is a known technique for the production of silk nanoparticles that can be coupled with microfluidics. The aim of this study was to explore the manufacturing space using the NanoAssemblr™ microfluidics system. Here, both unmodified and chemically modified silks from Bombyx mori were used; chemical modifications were at the serine residue to include carboxyl, alcohol (propanol) and alkane (butane) functional groups. The influence of silk degumming time, flow rate ratios (i.e. aqueous to organic solvent) and silk solution concentration on silk nanoparticle characteristics was studied. Based on this insight, chemically modified silk nanoparticles were prepared using microfluidics at a total flow rate of 1 mL/min, 1:5 ratio of silk to organic solvent (isopropanol) and 3% w/v aqueous solution concentration. Dynamic light scattering indicated that carboxy-modified and propanol-modified silk, but not butyl-modified silk, produced nanoscale particles. However, the particles, especially those derived from propanol-modified silk, demonstrated high polydispersity with a tendency to aggregate upon storage at 4°C owing to low zeta potential. All samples were subjected to secondary structure analysis showing the transition of soluble silk I (rich in α-helix) to β-sheet rich silk II. Further studies are warranted to fine-tune the process parameters to produce more uniform and stable particles or to search an alternative strategy (e.g. PEGylation) to increase stability in aqueous and biological media.