Polyanhydride-based Nanomedicine Platform for Combating Neurodegeneration Benjamin W. Schlichtmann1, Shivani Ghaisas2, Vellareddy Anantharam2, Anumantha Kanthasamy2, Surya Mallapragada1, and Balaji Narasimhan1. 1Chemical & Biological Engineering and 2Biomedical Sciences, Iowa State University, Ames, IA 50011 Statement of Purpose: Treatment for exposure to (blue arrows). The average NP size of NF-NPs and CPTP- chemical toxins such as pesticides has resulted in an NPs was 397 ± 143 nm and 287 ± 99 nm, respectively, estimated annual cost of $200 million in recent years [1]. which is in agreement with previous work [4]. Surface Exposure to these toxins leads to neurodegeneration, zeta potential measurements demonstrated a negligible including development of chronic conditions such as effect of functionalization on surface charge, as expected. Parkinson’s and Alzheimer’s diseases. Drugs that combat Non-functionalized neurodegeneration, such as antioxidants, must effectively pass through the blood-brain barrier (BBB), and then target diseased neurons and their mitochondria. The efficacy of drugs administered alone to do so is significantly hindered by drug metabolism and limited CPTP bulk-functionalized localization. Polyanhydride nanoparticles (NPs) have several favorable characteristics for drug delivery to overcome these issues and improve treatment of neurodegeneration [2]. Localization can be further Pre-CPTP (control) improved using targeting ligands by directly functionalizing the polyanhydrides to ensure that the ligand persists throughout NP degradation. The lipophilic cationic ligand triphenylphosphonium (TPP) has recently shown enhanced targeting of the BBB and mitochondria Figure 1. FTIR of functionalized and non-functionalized [3]. In this work, a derivative of TPP, (3-carboxypropyl) polymer showing functionalization by the relative triphenylphosphonium (CPTP) was used to functionalize decrease (red) of non-functionalized polymer end-group polyanhydrides. CPTP-functionalized NPs were then peaks and appearance (blue) of CPTP peaks. prepared and the biocompatibility of both non- functionalized and CPTP-functionalized NPs (NF-NP and Cytotoxicity testing on neurons showed a loss in viability CPTP-NP, respectively) was tested. at concentrations greater than 100 µg/mL, and no loss of viability at concentrations of 30 µg/mL or lower (Fig. 2). Methods: CPTP was conjugated to a polyanhydride There was a negligible effect on the amount of the copolymer made of sebacic anhydride and 1,6-bis(p- cationic CPTP on viability (Fig 2 mid, right). Preliminary carboxyphenoxy)hexane via an anhydride interchange viability studies using a toxicity model encapsulating the mechanism under high vacuum and temperature. Fourier antioxidant Mito-Apocynin indicated that this transform infrared spectroscopy (FTIR) and 1H nuclear nanomedicine platform provides efficacy. magnetic resonance (NMR; 400 MHz, CHCl3-d1) of functionalized polymer were used to evaluate functionalization. NPs were synthesized using a flash nanoprecipitation double emulsion method. NP morphology and size was evaluated with electron microscopy. A Malvern Zetasizer instrument was used to compare surface zeta potential between functionalized and non-functionalized NPs. Figure 2. Viability of NF-NP (left) and CPTP-NP (mid, right) formulations Cytotoxicity in rat N27 neurons was performed using an MTS assay to evaluate NP biocompatibility. NF-NPs and Conclusions: The synthesized CPTP-NP platform has CPTP-NPs were incubated with cells and absorbance was potential to enhance the delivery of drugs to the brain to measured using an MTS assay. treat neurodegeneration. The novel functionalization method developed is versatile and allows for rational Results: 1H NMR demonstrated functionalization by a design of a nanoscale delivery platform. Future studies significant decrease in the relative height of the non- will be conducted to further evaluate this platform for functionalized acyl end group in functionalized polymer. efficacy and brain localization. End-group analysis gave a percent functionalization of 50%. FTIR (Fig 1) demonstrated a replacement of methyl References: end groups with CPTP as well as relative reduction in [1] Langley RL. J Agromed. 2012;17:300-315. polymer-polymer anhydride bonds correlated with an [2] Binnebose AM. PLoS Negl. Trop. Dis. 2015;9:1-18. increase in the number of polymer-CPTP bonds (red [3] Ghosh A. J. Neuroimm. Pharmacol. 2016;11:259-278. arrows), and the appearance of CPTP-correlated peaks [4] Ulery BD. Pharm. Res. 2009;26:683-690. .