(368bu) Polymeric Hydrogels for Mitochondria Transplantation and Delivery

Mitochondria transplantation (MT) presents a promising approach for treating diseases associated with mitochondrial dysfunction, including neurodegenerative diseases, metabolic disorders, and conditions requiring tissue regeneration like spinal cord injuries (SCI). The ability to augment or replace damaged mitochondria with functional ones offers a novel therapeutic pathway, potentially circumventing the limitations of traditional treatments that merely alleviate symptoms without addressing underlying cellular energetics and dysfunction. Nonetheless, challenges such as maintaining mitochondrial viability in adverse environments and ensuring efficient cellular uptake hinder its efficacy. Our research addresses these obstacles by investigating the potential of thermoresponsive hydrogels in combination with hyaluronic acid (HA) as an effective delivery vehicle. HA is recognized for its unique biocompatibility and anti-inflammatory properties, existing in many parts of biological systems across the human body including central nervous system. On the other hand, the thermoresponsive polymers provide mechanical and drug release properties essential for efficient MT. This combination of co-polymers constitutes an ideal pairing to facilitate sustained and controlled mitochondrial delivery. For the purpose of the study, we investigated methylcellulose (MC) and Poly(N-isopropylacrylamide) (PNIPAm) for their unique phase separation properties at relatively low lower critical solution temperature (LCST), that is close to human body temperature. MC was blended with HA at various ratios and all thermoresponsive and mechanical properties has been studied in light of efficient delivery of mitochondria to SCI. PNIPAm was grafted onto HA (HA-PNIPAm) to make hydrogels that has unique release profiles and high MT efficacy. We synthesized various compositions and grafted hydrogels, evaluating their phase transition and gelation properties using ultraviolet-visible spectroscopy and dynamic scanning calorimetry. Hydrogels erosion and mitochondrial release over time were studied using a closed system drug dissolution module and a fluorescence microplate reader. Lastly, seahorse assay was used to study released mitochondria respiration and viability after incubation in HA-PNIPAm hydrogel.