Multifunctional chitosan–magnetic graphene quantum dot nanocomposites for the release of therapeutics from detachable and non-detachable biodegradable microneedle arrays

Biodegradable chitosan-magnetic graphene quantum dot (MGQD) nanocomposites were prepared and investigated for the release of small and large molecular weight (MWt) therapeutics from detachable and non-detachable biodegradable microneedle arrays. The presence of MGQDs in chitosan increased the electrical conductivity and biodegradation rate of chitosan while maintaining its mechanical properties. The detachable microneedle arrays were created by including a water-soluble ring of poly(ethylene glycol) (PEG) at the base of the microneedle, which enabled the rapid detachment of the microneedle shaft from the base. The PEG ring did not impede the microneedle array performance, with mechanical properties and a drug release profile of low MWt lidocaine hydrochloride similar to microneedle arrays without the ring. Without the PEG ring, the chitosan-MGQD microneedles were electrically conductive and allowed for electrically stimulated release of large MWt therapeutics which was challenging without the stimulation. These results demonstrate that chitosan nanocomposites containing MGQDs with intrinsic photoluminescent and supermagnetic properties are promising materials for developing multifunctional microneedles for targeted and tracked transdermal drug delivery.