Neonatal hypoxic-ischemic encephalopathy is the leading cause of permanent brain injury in term newborns and currently has no cure. Catalase, an antioxidant enzyme, is a promising therapeutic due to its ability to scavenge toxic reactive oxygen species and improve tissue oxygen status. However, upon in vivo administration, catalase is subject to a short half-life, rapid proteolytic degradation, immunogenicity, and an inability to penetrate the brain. Polymeric nanoparticles can improve pharmacokinetic properties of therapeutic cargo, although encapsulation of large proteins has been challenging. In this paper, we investigated hydrophobic ion pairing as a technique for increasing the hydrophobicity of catalase and driving its subsequent loading into a poly(lactic-co-glycolic acid)-poly(ethylene glycol) (PLGA-PEG) nanoparticle. We found improved formation of catalase-hydrophobic ion complexes with dextran sulfate (DS) compared to sodium dodecyl sulfate (SDS) or taurocholic acid (TA). Molecular dynamics simulations in a model system demonstrated retention of native protein structure after complexation with DS, but not SDS or TA. Using DS-catalase complexes, we developed catalase-loaded PLGA-PEG nanoparticles and evaluated their efficacy in the Vannucci model of unilateral hypoxic-ischemic brain injury in postnatal day 10 rats. Catalase-loaded nanoparticles retained enzymatic activity for at least 24 h in serum-like conditions, distributed through injured brain tissue, and delivered a significant neuroprotective effect compared to saline and blank nanoparticle controls. These results encourage further investigation of catalase and PLGA-PEG nanoparticle-mediated drug delivery for the treatment of neonatal brain injury. View Full-Text
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Metal–Organic Framework Induced Stabilization of Proteins in Polymeric Nanoparticles
Developing protein confinement platforms is an attractive research area that not only promotes protein delivery but also can result in artificial environment mimicking of the cellular one, impacting both the controlled release of proteins and the fundamental protein biophysics. Polymeric nanoparticles (PNPs) are attractive platforms to confine proteins due to their superior biocompatibility, low cytotoxicity, and controllable release under external stimuli. However, loading proteins into PNPs can be challenging due to the potential protein structural perturbation upon contacting the interior of PNPs. In this work, we developed a novel approach to encapsulate proteins in PNPs with the assistance of the zeolitic imidazolate framework (ZIF). Here, ZIF offers an additional protection layer to the target protein by forming the protein@ZIF composite via aqueous-phase cocrystallization. We demonstrated our platform using a model protein, lysozyme, and a widely studied PNP composed of poly(ethylene glycol)-poly(lactic-co-glycolic acid) (PEG–PLGA). A comprehensive study via standard loading and release tests as well as various spectroscopic techniques was carried out on lysozyme loaded onto PEG–PLGA with and without ZIF protection. As compared with the direct protein encapsulation, an additional layer with ZIF prior to loading offered enhanced loading capacity, reduced leaching, especially in the initial stage, led to slower release kinetics, and reduced secondary structural perturbation. Meanwhile, the function, cytotoxicity, and cellular uptake of proteins encapsulated within the ZIF-bound systems are decent. Our results demonstrated the use of ZIF in assisting in protein encapsulation in PNPs and established the basis for developing more sophisticated protein encapsulation platforms using a combination of materials of diverse molecular architectures and disciplines. As such, we anticipate that the protein-encapsulated ZIF systems will serve as future polymer protein confinement and delivery platforms for both fundamental biophysics and biochemistry research and biomedical applications where protein delivery is needed to support therapeutics and/or nutrients.
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- PAR ID:
- 10500910
- Publisher / Repository:
- American Chemical Society
- Date Published:
- Journal Name:
- ACS Applied Materials & Interfaces
- Volume:
- 16
- Issue:
- 12
- ISSN:
- 1944-8244
- Page Range / eLocation ID:
- 14405 to 14420
- Subject(s) / Keyword(s):
- polymeric nanoparticles lysozyme protein delivery metal−organic framework (MOF) zeolitic imidazolate framework (ZIF) encapsulation
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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