Combinatorial screening of nanoparticles for nose-to-brain RNA delivery to modulate neuroinflammation after traumatic brain injury

Traumatic brain injury (TBI)-induced neuroinflammation can evolve over weeks or months, contributing to ongoing secondary damage and worsening neurological recovery. RNA-based therapeutics hold great potential to regulate inflammatory signaling, but delivery to the brain remains challenging because of the blood brain barrier. Intranasal administration offers a direct non-invasive route for brain access but is often limited by low delivery efficiency. Here we constructed a combinatorial library of DNA-barcoded 103 lipid nanoparticles by varying lipid components with diverse headgroup chemistries and bioreactive moieties. A high throughput screening of these nanoparticles in vivo following intranasal administration led to the identification of top candidates with highest brain accumulation. Intranasal delivery of an antagomir targeting microRNA-9-5p loaded nanoparticle effectively reduced cerebral microRNA-9-5p levels, suppressed inflammatory markers, and improved neurological outcomes in TBI. These results demonstrate a systematic approach for optimizing intranasal lipid nanoparticle design and support the feasibility of RNA delivery to modulate neuroinflammation after brain injury.