Cancer Treatment using Electrospun fibers

Electrospinning is a highly versatile technique for producing small diameter fibers from various materials down to the nanometer scale. Its high surface area can be used for cancer treatment using different approaches. Anti-cancer drug may be incorporated into the fibers for controlled drug release. Fibers may also be imbued with heat generating capability for killing cancer cells due to their greater sensitivity to heat.

Hela cells on electrospun nanofibers.

Drugs can be incorporated into electrospun fibers via various means such as through simple blending or coaxial electrospinning. Blending is the most widely used method as it just involves mixing the drug into the polymer solution followed by electrospinning. Small amount of drugs may enhance the electrospinning process as they may contribute to the conductivity of the solution resulting in reduced fiber diameter [Li et al 2013]. However, there is limit on the amount of drugs that can be loaded into the solution without precipitation and adversely affect the quality of the electrospun fibers such as surface unevenness [Li et al 2013] and beads formation [Chen et al 2010]. Electrospun fibers may be organised hierarchically to build in different layers of drugs. Yang et al (2014) used a combination of blending micelle encapsulated circumin and hydrophilic doxorubicin hydrochloride (Dox) into polyvinyl alcohol (PVA) solution for electrospinning. The resultant fibers showed inhibitory effects on HeLa cells (Cervical cancer cells) which otherwise proliferate well on pure PVA fibers. Chen et al (2014) blended DOX loaded core-shell structured nanoparticles and indomethacin(MC) into a solution of poly(ε-caprolactone) and gelatin before electrospinning to form drug loaded fibrous mat. This mat is implanted on the tumor of rat tumour model. The study showed significant reduction in the tumor size with the multi-drug loaded nanofibrous mat after 18 days but the tumor size increases for rat that is injected with pure DOX and DOX loaded core-shell structured nanoparticles without the nanofiber carrier mat. This shows that the electrospun mat is very effective in localized and targeted delivery of the anti-cancer drugs.

Apart from drugs, other substances may also use electrospun fibers as delivery vehicles for cancer treatment. In cancer immunotherapy, the treatment involves the use of monoclonal antibodies, cancer vaccines or virus. Okada et al (2016) demonstrated the use of electrospun fibers as carriers for delivery of Hemagglutinating Virus of Japan Envelope (HVJ-E). This virus is rendered non-cytotoxic through UV irradiation which destroys its RNA but its cell fusion functionality remains and this has been shown to be able to induce cell selective tumor apoptosis. Layer-by-layer (LBL) technique was used for adsorption of HVJ-E on electrospun polycaprolactone (PCL) nanofibers layered with poly-L-Lysine (PLL) and Alginic acid (ALG). In vitro study showed that PCL nanofibers loaded with HVJ-E causes death of PC-3 (human prostate cancer) cells.

In cancer treatment, another approach is to use hyperthermia where localised heat is applied to the tumor as tumor cells are more sensitive to heat compared to normal tissue cells. Electrospun fibers may be embedded with magnetic particles for heat activation using an alternating magnetic field. Huang et al (2012) loaded polystyrene (PS) solution with iron oxide particles (IOP) before electrospinning to form a nanofibrous membrane. Up to 20wt% IOP may be added to the PS nanofiber without any apparent ill effect on the electrospinning process and fiber morphology. 282 mL of this composite fiber was able to heat 1 mL of water from 23 °C to 83 ° C within 3 minutes under an alternating magnetic field. Ovarian cancer cells attached to the membrane were killed when the membrane was heated to 45°C for 10 minutes.