Development and characterisation of co-axial electrosprayed curcumin-loaded mesoporous silica and polymer composite coated microneedles

The research presented adopts electrohydrodynamic atomisation (EHDA) technology to fabricate ideal nanocarriers incorporating curcumin to permeate across the skin strata. For the first time, we uncover the novel synthesis of curcumin-loaded mesoporous silica nanospheres (MSNs) surface functionalised by co-axial electrospraying (ES) and directly deposited onto microneedle (MN) devices. Curcumin was selected for its neuroprotective role however; its crystalline nature hampers its clinical application. To overcome this, the ES technique was utilised to encapsule poorly soluble curcumin when loaded into the silaceous network of MSNs. X-ray diffraction (XRD) and differential scanning calorimetry (DSC) data revealed the amorphous transformation of curcumin within the mesopores of the silica framework. In-silico docking analysis demonstrated stable properties of curcumin, PEG, PLGA and MSNs, offering insights into the drug-polymer interactions. Moreover, ES yielded nanoparticles below 150 nm with over 89 % encapsulation efficiency across all formulations, improving bioavailability and therapeutic effectivity of curcumin. For further potential therapeutic enhancement (and targeting efficacy), nanoparticles were engineered through co-axial technologies for sustained delivery aspects, forming core-shell coated MSNs (indicated by SEM, TEM and CLSM). Optimised formulations were electrosprayed onto solid MN devices for transdermal drug delivery systems (TDDS). Ex vivo studies utilising Franz cells achieved rapid permeation (74.72 ± 4.1 % in 40 min) for unencapsulated curcumin (F2) while Cur-loaded MSNs fabricated via coaxial electrospray (F8) provided sustained release (70.41 ± 3.8 % in 120 min). Furthermore, in vivo histopathological examination confirmed the successful piercing of MN shafts across the stratum corneum. The work herein establishes a foundation for the sustained delivery of curcumin-loaded MSNs, validating MN array patches as a treatment modality and paving the way for the development of advanced TDDS. Finally, coupled to what is known already, the outcomes shown provide a basis to explore opportunities for novel transdermal delivery systems.