Additively Manufactured Plasmonic Platforms for Light-Triggered and Programmable Drug Release

Gold nanoparticles possess the capacity to convert incident radiation into thermal energy through plasmonic effects, a behavior modulated by both particle size and geometry. This intrinsic property enables the spatiotemporal orchestration of active payload release from polymer-based pharmaceutical carriers, thereby reducing undesirable side reactions and unintended leakage. Three-dimensional printing, specifically the vat photopolymerization modality, has emerged as a powerful fabrication route for incorporating nanoparticulate components into architecturally sophisticated dosage forms. The present investigation aimed to embed gold nanospheres (AuNSs) and nanorods (AuNRs) within photocrosslinked polymeric scaffolds via vat photopolymerization, enabling externally regulated drug elution upon irradiation with 532 nm and 1064 nm light. Niclosamide (Lot 0000122971), Polyethylene glycol diacrylate with a molecular weight of 250 (PEGDA 250), Polyethylene glycol with a molecular weight of 400 (PEG 400), as well as diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide (TPO) as the radical photoinitiator, were all purchased from Sigma-Aldrich (St. Louis, MO, USA). Milli-Q ultrapure water, with a resistivity of 18.2 MΩ at 25 °C and filtered through a 0.22 µm membrane, was used in all experimental procedures. Except for explicitly stated cases, all other reagents and solvents were of analytical-grade purity. Statistical evaluation and graphical representation were performed using GraphPad Prism version 7.0 (GraphPad Software, San Diego, CA, USA). The AuNSs (27 nm diameter) displayed photo-responsiveness to 532 nm, whereas the AuNRs (measuring 60 nm in length and 10 nm in width) were activated by 1064 nm. Niclosamide was employed as the model therapeutic payload. Ternary formulations consisting of Polyethylene Glycol Diacrylate 250 (PEGDA 250), Polyethylene Glycol 400 (PEG 400), and water were systematically refined through DesignExpert 11 software to achieve irradiation wavelength-selective release kinetics. Three printable matrices, shortlisted according to solubility and fabrication fidelity, were subjected to exhaustive physicochemical profiling. Of these, two compositions successfully demonstrated gated drug liberation tuned to specific optical wavelengths. Bilayer architectures integrating both AuNSs and AuNRs within discrete compartments exhibited wavelength-discriminating drug release behavior. A light-activatable pharmaceutical construct was successfully engineered, capable of modulating drug output in direct response to optical stimulation, with translational promise for therapeutic regimens where deferred or pulsatile administration is clinically indicated.