Nano and submicrometric fibers of poly(D,L-lactide) (PDLLA or PLA) were spun from solutions using a solution blow spinning (SBS) apparatus. Fiber morphology and diameter were investigated by scanning electron microscopy as a function of polymer concentration, feed rate, and air pressure. A more systematic understanding of the SBS process parameters was obtained, and a quantitative relationship between these parameters and average fiber diameter was established by design of experiments and response surface methodology. It was observed that polymer concentration played an important role in fiber diameter, which ranges from 70 to 2000 nm, and its distribution. Lower polymer concentration tended to increase the formation of bead-on-string structures, whereas smooth fibers were formed at higher concentrations. Fiber diameter tended to increase with polymer concentration and decrease with feed rate. Based on these results, optimal conditions could be obtained for solution-blow spun fibers.

Blends of thermoplastic cornstarch (TPS) and chitosan (TPC) were obtained by melt extrusion. The effect of TPC incorporation in TPS matrix and polymer interaction on morphology and thermal and mechanical properties were investigated. Possible interactions between the starch molecules and thermoplastic chitosan were assessed by XRD and FTIR techniques. Scanning Electron Microscopy (SEM) analyses showed a homogeneous fracture surface without the presence of starch granules or chitosan aggregates. Although the incorporation of thermoplastic chitosan caused a decrease in both tensile strength and stiffness, films with better extensibility and thermal stability were produced.

Functional polymeric micro-/nanofibers have emerged as promising materials for the construction of structures potentially useful in biomedical fields. Among all kinds of technologies to produce polymer fibers, spinning methods have gained considerable attention. Herein, we provide a recent review on advances in the design of micro-and nanofibrous platforms via spinning techniques for biomedical applications. Specifically, we emphasize electrospinning, solution blow spinning, centrifugal spinning, and microfluidic spinning approaches. We first introduce the fundamentals of these spinning methods and then highlight the potential biomedical applications of such micro-and nanostructured fibers for drug delivery, tissue engineering, regenerative medicine, disease modeling, and sensing/biosensing. Finally, we outline the current challenges and future perspectives of spinning techniques for the practical applications of polymer fibers in the biomedical field.

. Roberto Ezequiel Heymann and Eduardo dos Santos Paiva received honorariums from Lilly, Janssen-Cilag, Boehringer, Apsen, and Pfizer for speeches and consulting services; Milton Helfenstein Junior received honorariums from Pfizer and Merck Sharp for speeches and consulting services; Daniel Feldman Pollak received honorariums from Lilly, Pfizer, and Merck Sharp; José Eduardo Martinez received honorariums from Sanofi Aventis, for speeches, and Pfizzer, for speeches and consulting services; José Roberto Provenza received honorariums from Roche, Bristol, Ache, and Pfizer to participate in clinical studies with new drugs at PUC-Campinas; Marcelo Cruz Rezende received honorariums from LillyBoehringer, to participate in symposiums, and from Pfizer, for speeches and to participate in sympostiums; valério valim Cristo received honorariums from Roche for presentations, conferences, or speeches, besides financing for studies, teaching organization, or to attend symposiums sponsored by Lilly, Genzyme, and Schering-Plough.