Electrospun Nanofibers: Recent Applications in Drug Delivery and Cancer Therapy

Abstract

Polymeric nanofibers (NFs) have been extensively reported as a biocompatible scaffold to be specifically applied in several researching fields, including biomedical applications. The principal researching lines cover the encapsulation of antitumor drugs for controlled drug delivery applications, scaffolds structures for tissue engineering and regenerative medicine, as well as magnetic or plasmonic hyperthermia to be applied in the reduction of cancer tumors. This makes NFs useful as therapeutic implantable patches or mats to be implemented in numerous biomedical researching fields. In this context, several biocompatible polymers with excellent biocompatibility and biodegradability including poly lactic-co-glycolic acid (PLGA), poly butylcyanoacrylate (PBCA), poly ethylenglycol (PEG), poly (ε-caprolactone) (PCL) or poly lactic acid (PLA) have been widely used for the synthesis of NFs using the electrospun technique. Indeed, other types of polymers with stimuli-responsive capabilities has have recently reported for the fabrication of polymeric NFs scaffolds with relevant biomedical applications. Importantly, colloidal nanoparticles used as nanocarriers and non-biodegradable structures have been also incorporated by electrospinning into polymeric NFs for drug delivery applications and cancer treatments. In this review, we focus on the incorporation of drugs into polymeric NFs for drug delivery and cancer treatment applications. However, the principal novelty compared with previously reported publications is that we also focus on recent investigations concerning new strategies that increase drug delivery and cancer treatments efficiencies, such as the incorporation of colloidal nanoparticles into polymeric NFs, the possibility to fabricate NFs with the capability to respond to external environments, and finally, the synthesis of hybrid polymeric NFs containing carbon nanotubes, magnetic and gold nanoparticles, with magnetic and plasmonic hyperthermia applicability.

Keywords: biocompatible polymers; cancer treatment; drug release; electrospun nanofibers; hyperthermia; nanomedicine.

Figure 1

Schematic representation of the coaxial electrospinning setup. In this example the core solution is composed by the PTX dissolved in 2,2,2-trifluoroethanol and the shell solution is the poly(L-lactic acid-co-ε-caprolactone) polymer. Reprinted with permission from reference [27]. Copyright Wiley Online Library, 2009.

Figure 2

Schematic representation of the preparation of hydrophilic/hydrophobic electrospun composite fibers. (A) Accumulation of the drug mixture into the vesicle and (B) incorporation into the NF by electrospinning and drug release. Reprinted with permission from reference [33]. Copyright American Chemical Society, 2015.

Figure 3

Schematic illustration for the process of fabrication of DOX@MSNs-IN-NFs electrospun composite NFs and the location of DOX in the fiber [40].

Figure 4

Stimuli-responsive NFs. Once NFs are synthesized by the electrospinning process and loaded with the antitumor drug, treatment may be applied in an experimental mouse model that carries a specific type of tumor. Once the treatment has been inoculated, an internal stimulus, such as the low pH present in the tumor tissues, or an external stimulus such as a temperature rise, stimulate the release of the drug at the specific site of the tumor, thus applying the treatment on tumor cells. Reprinted with permission from reference [62]. Copyright American Chemical Society, 2016.

Figure 5

Schematic illustration for the fabrication process of PLGA/DOX-IN-CNTs electrospun composite NFs. The morphology and diameter distributions of PLGA and PLGA/DOX@CNTs composite NFs [74].

Figure 6

SEM micrographs of PVA/(graphene foam and expanded graphite) NFs at 2 kV operating voltage for (A) solution with 0.02 g GF concentration, (B) solution with 0.08 g GF concentration, (C) solution with 0.02 g EG concentration and (D) solution with 0.08 g EG. Reprinted with permission from reference [77]. Copyright Elsevier, 2015.

Figure 7

(A) TEM image of the iron oxide NPs (the inset shows the corresponding selected-area electron diffraction pattern), (B,C) FESEM images of electrospun PLGA (poly lactic-co-glycolic acid) NFs and magnetic NF matrix, respectively, (D) TEM image of MNF. Reprinted with permission from reference [94]. Copyright Elsevier, 2016.

Figure 8

TEM images of (A) Au nanorods (AuNRs), (B) AuNRs/PNIPAM electrospun fibers and (C) photograph of AuNRs/PNIPAM composite film immersed in water. Reprinted with permission from reference [97]. Copyright ACS Publications, 2017.