Biology subjects

Stabenfeldt, S. E.

Publications and source records attributed to Stabenfeldt, S. E..

7 recordsLinked to original sources

bioRxiv2026

Solvent-free Nanoparticle Assembly Protocol (SNAP): one-pot formulation of drug loaded polyester nanoparticles and their vessel size-dependent perivascular transport

This work describes a new approach for rapid and reproducible formulation of drug loaded biodegradable nanoparticles based on polyester copolymers, including poly(lactic acid)-poly(ethylene glycol) (PLA-PEG) and poly(caprolactone)-poly(ethylene glycol) (PCL-PEG). The new approach, termed Solvent-free Nanoparticle Assembly Protocol (SNAP), carries several advantages over conventional polyester formulation strategies, including very rapid formulation (minutes) and the ability to use nanoparticles immediately without lengthy solvent evaporation or washing steps. Altering polyester molecular weight and concentration, alongside the introduction of specific functional groups yielded precise control of nanoparticle properties, including size, shape, surface charge, drug release and loading. We examined loading of multiple therapeutic compounds, including diclofenac, loperamide, bortezomib, CT179, panobinostat, docetaxel, methotrexate, and camptothecin. The SNAP protocol facilitated the rapid production of stable, drug-loaded nanoparticles with a narrow size distribution and generally good drug loading. Using Fluorescence Resonance Energy Transfer (FRET) and size exclusion chromatography (SEC) with a focus on the model agent Rhodamine B, we were able to carefully examine stability of the nanoparticle and assess the distribution of small molecules within the polymer as well as nanoparticle stability. In vivo evaluation of fluorescently labeled nanoparticles using real-time, intravital microscopy showed that, after direct administration to cerebrospinal fluid (CSF) via the intrathecal cisterna magna (IT-CM) route, the dynamic accumulation of nanoparticles within the perivascular space (PVS) depends on the size of the vessel that is imaged. Nanoparticles accumulated steadily within the PVS of large vessels, while accumulating more slowly and exhibiting clearance from medium-sized and smaller vessels over the course of several hours. In sum, these studies present a new platform for facile production of polyester nanoparticles, demonstrate their ability to encapsulate a variety of hydrophobic small molecules, and expand our knowledge on the development of nanocarriers for intrathecal administration. Taken together, these data open new opportunities for development safer and more effective nanoparticle-based therapies.

bioengineering↗

bioRxiv2026

Biomimetic MRI Nanoprobe for Mapping Cerebrovascular Inflammation After Traumatic Brain Injury

Cerebrovascular inflammation is a critical driver of secondary injury following traumatic brain injury (TBI), yet no noninvasive tool currently exists to map its spatial heterogeneity across the injured brain. Here, we report MoNP-SPION, a monocyte-mimetic nanoprobe that selectively targets activated cerebrovascular endothelium after TBI and enables quantitative MRI of spatiotemporally heterogeneous cerebrovascular inflammation. MoNP-SPION binding to inflamed brain endothelium scaled with activation state, enabling rapid, spatially heterogeneous targeting of injured cerebral vasculature. MoNP-SPION-enhanced MRI revealed dynamic reductions in T2* throughout the brain that extended beyond the injury penumbra and captured both subacute vascular injury and therapy-induced recovery. Importantly, spatiotemporal reductions in T2* strongly correlated with VCAM1 upregulation, supporting MoNP-SPION as a molecularly specific readout of endothelial activation. Together, these findings establish MoNP-SPION as a promising platform for longitudinal, noninvasive monitoring of cerebrovascular inflammation in TBI and other neurological disorders involving vascular dysfunction. TEASERCell-mimicking MRI nanoprobe maps cerebrovascular injury and recovery dynamics following brain trauma.

bioengineering↗

bioRxiv2026

Differential sex-dependent responses of circulating steroid hormones and cortical gene expression in a preclinical traumatic brain injury model

Accumulating evidence supports sex differences in traumatic brain injury (TBI) outcomes, however the underlying processes that lead to sex differences are not well understood. TBI results in the initiation of molecular and cellular responses that facilitate the progression of neurodegeneration. Importantly, little is known about how the circulating hormone profile is altered in response to TBI, and whether sex differences in endocrine responses might shape secondary injury pathologies. Using intact male and female mice in a preclinical TBI model, we assessed changes in plasma hormone concentrations and cortical gene expression at 24 and 72 hours after TBI. We demonstrate that males and females exhibit sex-specific alterations in circulating levels of progesterone, testosterone, androstenedione, estradiol and dehydroepiandrosterone (DHEA) in response to TBI. We also identified sex differences in the expression of genes that are involved in immune responses and tissue remodeling after injury. Moreover, we report divergent circulating hormone and gene expression correlations between sexes.

neuroscience↗

bioRxiv2024

Vaccines for immunological defense against traumatic brain injury

Traumatic brain injury (TBI) and subsequent neurodegeneration is partially driven by chronic inflammation both locally and systemically. Yet, current clinical intervention strategies do not mitigate inflammation sequalae necessitating the development of innovative approaches to reduce inflammation and minimize deleterious effects of TBI. Herein, a subcutaneous formulation based on polymer of alpha-ketoglutarate (paKG) delivering glycolytic inhibitor PFK15 (PFKFB3 inhibitor, a rate limiting step in glycolysis), alpha-ketoglutarate (to fuel Krebs cycle) and peptide antigen from myelin proteolipid protein (PLP139-151) was utilized as the prophylactic immunosuppressive formulation in a mouse model of TBI. In vitro, the paKG(PFK15+PLP) vaccine formulation stimulated proliferation of immunosuppressive regulatory T cells and induced generation of T helper-2 cells. When given subcutaneously in the periphery to two weeks prior to mice sustaining a TBI, the active vaccine formulation increased frequency of immunosuppressive macrophages and dendritic cells in the periphery and the brain at day 7 post- TBI and by 28 days post-TBI enhanced PLP-specific immunosuppressive cells infiltrated the brain. While immunohistology measurements of neuroinflammation were not altered 28 days post-TBI, the vaccine formulation improved motor function and enhanced autophagy mediated genes in a spatial manner in the brain. Overall, these data suggest that the TBI vaccine formulation successfully induced an anti-inflammatory profile and decreased TBI-associated inflammation. TeaserIn this study, a vaccine formulation was generated to develop central nervous specific immunosuppressive responses for TBI.

bioengineering↗

bioRxiv2021

GdDO3NI allows imaging of hypoxia after brain injury

PurposeIn this study, we use the hypoxia targeting agent (GdDO3NI, a nitroimidazole-based T1 MRI contrast agent) for imaging hypoxia in the injured brain after experimental traumatic brain injury (TBI) using magnetic resonance imaging (MRI), and validate the results with immunohistochemistry (IHC) using pimonidazole. MethodsTBI induced mice (controlled cortical impact model) were imaged at 7T using a T2 weighted fast spin-echo sequence to estimate the extent of the injury. The mice were then were intravenously injected with either conventional T1 agent (gadoteridol) or GdDO3NI at 0.3 mmol/kg dose (n=5 for each cohort) along with pimonidazole (60 mg/kg). Mice were imaged pre- and post-contrast using a T1-weighted spin-echo sequence for three hours. Regions of interests were drawn on the brain injury region, the contralateral brain as well as on the cheek muscle region for comparison of contrast kinetics. Brains were harvested immediately post imaging for immunohistochemical analysis. ResultsGdDO3NI is retained in the injury region for up to 3 hours post-injection (p< 0.05 compared to gadoteridol) while it rapidly clears out of the muscle region. On the other hand, conventional MRI contrast agent gadoteridol clears out of both the injury region and muscle rapidly, although with a relatively more delayed wash out in the injury region. Minimal contrast enhancement was seen for both agents in the contralateral hemisphere. Pimonidazole staining confirms the presence of hypoxia in both gadoteridol and GdDO3NI cohorts, and the later cohort shows good agreement with MRI contrast enhancement. ConclusionGdDO3NI was successfully shown to visualize hypoxia in the brain post-TBI using T1-wt MRI.

bioengineering↗

bioRxiv2020

Uncovering temporally sensitive targeting motifs for traumatic brain injury via phage display

The heterogeneous injury pathophysiology of traumatic brain injury (TBI) is a barrier to developing highly sensitive and specific diagnostic tools. Embracing neural injury complexity is critical for the development and advancement of diagnostics and therapeutics. The current study employs a unique discovery pipeline to identify targeting motifs that recognize specific phases of TBI pathology. This pipeline entails in vivo biopanning with a domain antibody (dAb) phage display library, next generation sequencing (NGS) analysis, and peptide synthesis. Here, we identify targeting motifs based on the HCDR3 structure of dAbs for acute (1 day) and subacute (7 days) post-injury timepoints using a mouse controlled cortical impact model. Their bioreactivity was validated using immunohistochemistry and candidate target epitopes were identified via immunoprecipitation-mass spectrometry. The acute targeting motif recognizes targets associated with metabolic and mitochondrial dysfunction whereas the subacute motif was largely associated with neurodegenerative processes. This phage display biomarker discovery pipeline for TBI successfully achieved discovery of temporally specific TBI targeting motif/epitope pairs that will advance the TBI diagnostics and therapeutics.

bioengineering↗

bioRxiv2019

Sex-dependent macromolecule and nanoparticle delivery in experimental brain injury

Development of effective therapeutics for brain disorders is challenging, in particular, the blood-brain barrier (BBB) severely limits access of the therapeutics into the brain parenchyma. Traumatic brain injury (TBI) may lead to transient BBB permeability that affords a unique opportunity for therapeutic delivery via intravenous administration ranging from macromolecules to nanoparticles (NP) for developing precision therapeutics. In this regard, we address critical gaps in understanding the range/size of therapeutics, delivery window(s), and moreover the potential impact of biological factors for optimal delivery parameters. Here we show, for the first time, to the best of our knowledge, that 24 h post-focal TBI female mice exhibit a heightened macromolecular tracer and NP accumulation compared to male mice, indicating sex-dependent differences in BBB permeability. Furthermore, we report for the first time the potential to deliver NP-based therapeutics within 3 d after focal injury in both female and male mice. The delineation of injury-induced BBB permeability with respect to sex and temporal profile is essential to more accurately tailor time-dependent precision and personalized nanotherapeutics.

bioengineering↗