Rational design of microfluidic templated HA-LPEI nanogels for the targeted delivery of doxorubicin

Hyaluronan-based nanomaterials represent an intriguing class of materials for drug delivery applications. In this scenario, continuous flow syntheses hold promise for superior control over process parameters, leading to more homogeneous and reproducible nanomaterials. However, the high sensitivity to parameter variation necessitates extensive and time-consuming experiments to ascertain the optimal process conditions. This study explores the implementation of a Response Surface Methodology (RSM) supporting the rational design of hyaluronic acid (HA) - linear polyethyleneimine (LPEI) nanogels (NGs) via droplet-based microfluidics for the intracellular delivery of doxorubicin. The RSM approach facilitated the development of an empirical model predicting NG physico-chemical properties and biological performance as a function of process parameters (namely, the flow rate ratio (FRR) between the internal and external phases and the LPEI/HA monomer molar ratio (MR) of the polymeric precursors) with high accuracy levels. Results indicate that FRR predominantly influences NG size, which ranges between 100 and 400 nm, and polydispersity (0.01-0.1), while MR affects composition, cytocompatibility, cellular uptake and NP-mediated drug effect. In particular, increased HA content resulted in improved cytocompatibility and enhanced cellular uptake. Overall, this work underscores the key role of RSM in advancing the synthesis of hyaluronan-based nanomaterials for drug delivery applications.