2024 AIChE Annual Meeting

Assembling Neural Endosome Targeted Nanoparticles for Pain Drug Delivery Via Flash Nanoprecipitation

Chronic pain, a neurological condition affecting one-third of the adult population, is inadequately treated with existing medications. Recent pharmacological research suggests that pain receptors within neuronal endosomes mediate pain. However, current medications only block cell surface protein receptors, while endocytosed receptors continue to release pain signals. Drug-loaded nanoparticles offer a potential solution by delivering drugs directly to endosomes.

In this work, we are designing and optimizing nanoparticle vehicles to deliver pain therapeutics by studying nano-neuro interactions and pain behavior in sensory neurons. We have assembled a tunable core-shell nanoparticle library composed of three polymeric surfaces: polyethylene glycol (PEG), poly(ethylene oxide-co-glycidyl methyl ether) (rPEG), and poly-2-ethyl-2-oxazoline (P2OX), using Flash NanoPrecipitation (FNP). Two fluorophores, Rubrene and Dioctadecyloxacarbocyanine (DiO), were encapsulated in the core to visualize nano-neuro interactions via confocal microscopy. We observed colocalization between endosomes and nanoparticles by transfecting cells with Rab5a-GFP. The association rates of the nanoparticles in immortalized dorsal root ganglion neurons (F11) were characterized using flow cytometry.

Importantly, we present the first use of the F11 cell line with nanoparticle delivery and support its validation as a sensory neuron model for pain research. FNP is validated as a successful approach for synthesizing tunable and modular fluorescent nanoparticles. Our findings show that PEG, rPEG, and P2OX each exhibit distinct uptake rates and trafficking patterns in F11 cells. Endosome colocalization signals indicate a decreasing level of overlap from PEG to rPEG to P2OX.

Our results suggest that rPEG and P2OX may serve as alternative nanoparticle surfaces to PEG. Nanoparticles observed in endosomes along axon regions indicate that the vehicles have entered cells at nerve endings and can potentially interfere with pain signaling. Evidence of retrograde transport of nanoparticles highlights their potential clinical efficacy. Future work will involve using endocytosis and inhibitors to study endosomal pathways and further substantiate nano-neuro interactions in vivo. With these findings, we are closer to achieving more efficient drug delivery for chronic pain and other neurological disorders.