Microfluidics-based synthesized ZIF-8 nanoparticles embedded inside a natural scaffold for sustained-release of cargo in drug delivery purposes

Introduction: The growing field of nanotechnology requires the use of scalable devices such as microfluidic-based channels. These reproducible setups ensure time and labor-saving methods for nanoparticle synthesis. Synthesis of porous ZIF-8 nanoparticles can result in better loading and more controlled release, as well as pH-responsiveness, which are important in cancers and inflammatory diseases alike. Embedding the drug-loaded nanomaterials inside a natural scaffold such as wood adds to the mechanical and controlled-release effects needed in multiple drug delivery aspects.

Methods: The synthesis of drug@ZIF-8 nanoparticles was facilitated through microfluidic tubes. Five different flow rate combinations, 2 different solvents, and 2 different ligand/metal molar ratios were chosen based on the literature in order to reach the optimal size and polydispersity index (PDI) for ZIF-8 nanoparticles. Characterization of the drug/ZIF-8/wood scaffold was performed using scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) to assess its structural integrity. Loading and release tests were also conducted.

Results: Morphology and characterization results were assessed. SEM showed a uniform rhombic dodecahedron structure, presenting successful ZIF-8 synthesis with low PDI and less than 200 nm size. Loading capacity (LC%) was 11.68%, with encapsulation efficiency (EE%) of around 76%. The release of statin from ZIF-8 nanoparticles was evaluated in phosphate-buffered saline (PBS) with 2 pH values, revealing a burst profile, while a sustained release profile was observed from the scaffold, taking two months to reach full release. pH-responsive behavior was observed, which is beneficial for drug delivery towards inflamed areas.

Conclusion: This study presents the construction and evaluation of a novel wood-based scaffold integrated with microfluidics-synthesized ZIF-8 nanoparticles aimed at promoting drug delivery aspects such as loading and release profile.

The scaffold represents a promising strategy for tissue regeneration, a field that may benefit from slow and pH-triggered release for better outcomes.