Electrospinning Stimuli-Responsive Fibers at the Nanoscale As Functional Drug Delivery Mats

Skin tissue engineering and drug delivery are very relevant fields of research in the health industry. Due to certain responses of the immune system, there has yet to be a development of proper skin tissue substitutes. A challenge that arises with this area of research is replicating a three-dimensional scaffold that has the same function and structures as the natural extracellular matrix. The scaffolds provide an alternative to the use of allografts and autografts and can be also used for bone repair.² A technique that has gained attention within this field of research in the last couple of decades is electrospinning. This new technology allows scaffolds to be created through electrospun nanoscale fibers with a large range of diameters, which produces a porous structure with a high surface area.¹ In addition to research of skin tissue engineering, drug delivery proves to be another promising application of electrospun fibers. The high loading capacity and localized Ð but time released Ð delivery of a large amount of therapies, along with the cost effective processing technique of electrospinning, make scaffold-facilitated drug delivery highly attractive. Dependent on whether degradable or non-degradable materials are use, the drug release can occur via diffusion or scaffold degradation.³ The delivery rate at which the drug is released can also be altered, allowing for a larger range of drugs able to be delivered such as antibiotics, anticancer drugs, proteins and DNA.³

The objective of this research is to create biodegradable mats with tunable characteristics such as fiber diameter and surface area. The functional drug delivery mats enable disease-tailored therapies with targeted delivery to reduce side effects in patients. Using a large electric potential to draw fibers from a solution flowing at a specific rate, the solution reaches a grounded target several inches away. The biodegradable controlled drug delivery polymer used was poly(lactic acid-co-glycolic acid) (PLGA). PLGA solutions of 11 Ð 14 wt.% were prepared by dissolving the block copolymer in a solvent mixture containing tetrahydrofuran (THF) and dimethylformamide (DMF) at a 3:1 volumetric ratio. They were then electrospun at distances of 7 and 18 cm and rates ranging from 0.8 to 4 mL/h at a voltage of 15 kV. The nanoscale fibers will be used as drug delivery mats and the kinetics of the peptideÕs release-time will be tuned to occur in the range of one hour to a week. In addition, solution rheology was performed on each PLGA solution to measure viscosity, which is directly correlated to the fiber diameter of the electrospun mats. Observing the impact of solvent on fiber spinning and fiber diameter brings about many positive results in developing fully characterized and well-understood fibrous mats for drug delivery.

Work Cited

¹Ru, C.; Wang, F.; Pang, M.; et. al; Suspended, shrinkage-free, electrospun PLGA nanofibrous scaffold for skin tissue engineering. American Chemical Society 2015, 10872-10977.

²Gentile, P.; Chiono, V.; Camagnola, I.; Hatton, P., An overview of PLGA-based biomaterials for bone tissue engineering. International Journal of Molecular Sciences 2014, 3640-3659.

³Sill, T.; Recum, H., Electrospinning: Applications in drug delivery and tissue engineering. Biomaterials 2008, 29.