Biology subjects

Song, P.

Publications and source records attributed to Song, P..

At least 37 records · Page 2Linked to original sources

bioRxiv2025

Highly controllable co-delivery of siRNA and doxorubicin via cationic niosomes for synergistic anticancer effects

The combination of anticancer drugs and siRNA has emerged as a promising strategy for cancer therapy due to their synergistic effects. However, a major challenge is developing a co-delivery system with high controllability capable of simultaneously encapsulating both the chemical drug and siRNA. In this study, we developed a simple and highly controllable co-delivery system for delivering Doxorubicin (Dox) and siRNA. Co-encapsulation was achieved by intercalating Dox into duplex GC-rich oligodeoxynucleotides, (CGA)7/(TCG)7 (termed CGA-Dox), followed by mixing with siRNA and subsequent condensation using a cationic noisome (SPN) through electrostatic interactions. SPN/siRNA/Dox exhibited efficient cellular uptake and high gene silencing efficiency in both H1299 and MDA-MB-231 cells. Furthermore, co-delivery of Dox and siRNA targeting ribonucleotide reductase subunit M2 (RRM2) using this system significantly enhanced cellular apoptosis and antiproliferative effect in MDA-MB-231 cells compared to Dox alone. These results indicate that our co-delivery system constructed via Dox-DNA intercalation and electrostatic complexation, represents a promising strategy for synergistic anticancer therapy.

bioengineering↗

bioRxiv2025

Optimizing C14120-based LNPs for in vitro and in vivo mRNA delivery

Lipid nanoparticles (LNPs) have proven to be an effective delivery system for RNA therapeutics. The chemical composition of LNPs determines their functional delivery efficiency and targeting properties, which vary between in vitro and in vivo contexts. Here, we have systematically characterized and compared twenty-five novel C14120-based LNP formulations for mRNA delivery in vitro and assessed in vivo mRNA expression and biodistribution using deep sequencing of DNA barcodes in a pooled LNP-mRNA library. In vitro experiments showed correlations of lipid composition with particle size and mRNA transfection efficiency in 4 different cell lines of distinct tissue and species origin. In vivo experiments employed a pooled LNP delivery of luciferase mRNA in combination with a multiplexed barcode system, revealed strong mRNA expression after 6 hours and identified LNP compositions with organ-specific targeting properties. Individual validation of three selected LNP candidates based on mRNA expression analysis confirmed high specificity for the lung-targeting candidate, lower specificity for the liver-targeting candidate, and inconclusive results for the spleen-targeting candidate. These findings identify LNP formulations with promising potential for in vitro and in vivo organ-targeted delivery.

bioengineering↗

bioRxiv2025

Delivery and expression of mRNA therapeutics during ex vivo kidney perfusion: A feasibility study in porcine and human donor kidneys

Achieving efficient mRNA delivery and expression in intact solid organs beyond the liver remains a major challenge for advancing mRNA therapeutics. Normothermic machine perfusion (NMP) provides a clinically relevant ex vivo platform for targeted intervention during donor organ preservation, minimizing systemic exposure and enabling organ-confined mRNA delivery. Here, we demonstrate that intra-arterial infusion of lipid nanoparticles (LNPs) encapsulating reporter mRNAs during kidney NMP enables robust, organ-wide protein expression in human-sized porcine donor kidneys. Engineered LNP formulations were first evaluated for stability and efficacy in kidney cell lines, where LNPs pegylated with TPGS (D--tocopherol polyethylene glycol 1000 succinate) achieved the highest reporter protein expression levels. Next, the LNP-encapsulated mRNAs were introduced into porcine kidneys via a 5-minute infusion during NMP. mCherry and human erythropoietin (hEPO) mRNAs were delivered via the renal artery, serving as intracellular and secreted reporters, respectively. The perfusion was continued for 6-12h after LNP-mRNA infusion with the erythrocyte-based perfusate at 37 {degrees}C. LNP-mRNA administration resulted in widespread parenchymal mRNA uptake and rapid, robust reporter protein expression that continued to increase over the perfusion period. hEPO protein was detected in perfusate and urine, while mCherry expression localized to endothelial and tubular cells within the renal parenchyma. Consistent with the in vitro data, TPGS-LNPs produced the highest expression during NMP. Importantly, LNP-mediated mRNA delivery during NMP did not affect perfusion parameters or histological integrity. These findings demonstrate successful mRNA-driven protein expression in intact donor kidneys, establishing NMP as a clinically relevant route for organ-specific RNA delivery and protein expression modulation. One sentence summaryUsing a clinically compatible normothermic machine perfusion model, we demonstrate that lipid nanoparticle-mediated mRNA delivery enables rapid, organ-wide protein expression in human-sized porcine donor kidneys.

bioengineering↗

bioRxiv2025

Microbubble Track-based Functional Ultrasound Localization Microscopy in Awake Mice

Functional neuroimaging with ultrafast ultrasound is an emerging neuroimaging tool for studying neural activities in the rodent brain. Existing methods, however, are challenged by the compromise between functional imaging sensitivity (i.e., sensitivity in detecting neural responses) and spatial resolution. For example, functional ultrasound (fUS) uses native red blood cells (RBCs) as imaging targets, which offers high functional imaging sensitivity but limited spatial resolution that is confined by the diffraction limit of ultrasound. On the other hand, functional ultrasound localization microscopy (fULM) employs intravenously injected microbubble (MB) as contrast agent to achieve super-resolved spatial resolution but at the cost of functional imaging sensitivity. This study aims to address this challenge by developing a novel, MB track-based hemodynamic activity estimation method to enhance the functional imaging sensitivity of fULM. Our approach involves conducting functional correlation analysis using the MB signals acquired from the entire MB movement track rather than individual MB centroid locations, which overcomes the signal sparsity issue in fULM. To further boost the functional sensitivity of fULM, we developed a novel approach based on indwelling jugular vein catheters to achieve fULM imaging in awake mice. The in vivo imaging results demonstrate that the proposed techniques successfully enhanced the functional imaging sensitivity of fULM without compromising its high spatial resolution. In the whisker stimulation experiments, the proposed technique enabled detection of significantly activated brain regions within fewer than five stimulation cycles (5 minutes of acquisition), reducing the required time by over 50% compared to conventional fULM.

bioengineering↗

bioRxiv2025

Comparison and Dynamic interaction between Auditory Cortex and Prefrontal Cortex of Behaving Monkeys during Novelty Detection

The ability to detect deviations from expected sensory input is fundamental for adaptive behavior. We recorded electrocorticographic activity from the auditory (AC) and prefrontal (PFC) cortices of behaving macaques during an auditory oddball task to probe the cortical dynamics of predictive processing. Repetition of standard stimuli evoked suppression and facilitation in AC and strong low-frequency (2 Hz) enhancement in PFC, accompanied by bidirectional delta-band coupling indicative of a shared predictive state. Deviant stimuli triggered early AC responses followed by PFC activation and increased feedforward and feedback connectivity across delta, theta, and gamma bands. Behavioral engagement amplified both prediction and prediction error signals, strengthening cortical network coordination. Together, these findings reveal a hierarchical predictive network in which the AC encodes sensory regularities and violations, while the PFC integrates predictive context in a behaviorally dependent manner.

neuroscience↗

bioRxiv2025

Multifunctional semiconducting polymer dots as a miRNA delivery system for osteogenic differentiation and stem cell tracking

Small interfering RNAs (siRNA) and microRNAs (miRNA) are potent gene regulators through RNA interference (RNAi). In this study, we developed a multifunctional theranostic carrier for small RNA delivery and cell tracking using a polymer based nanoparticle composed of the lipid-like material S14, Pluronic F127 and semiconducting polymer MEH-PPV (SPM-dots). The resulting SPM-dots showed efficient siRNA transfection and labeling of human mesenchymal stem cells (hMSCs). Delivery of miR-29b to hMSCs significantly enhanced osteogenic differentiation. Furthermore, hMSCs transfected with SPM-dots displayed strong fluorescent signals in vivo after subcutaneous transplantation. These findings indicate that SPM-dots hold great potential as carrier for gene delivery and cell tracking applications.

bioengineering↗

bioRxiv2025

Walking Selectively Modulates Behaviorally Relevant Auditory Responses According to Stride Cycle Phase

Perception in natural environments unfolds while the body is in motion, yet how locomotion shapes cortical computations for fine-grained and dynamic scene analysis remains unclear. Here, we combined over-ground walking with mobile EEG and a transitional click-train paradigm to test how natural locomotion influences auditory processing in humans. Participants listened to two-segment click trains in which a subtle inter-click-interval (ICI) change signaled a pitch shift and performed a task-engaged change-detection task while either sitting or walking; an independent cohort also completed a passive-listening version. Walking elevated behavioral detection thresholds and slowed responses, indicating reduced sensitivity to fine temporal changes. Neurally, locomotion produced a response-component-specific attenuation: activity time-locked to the ICI transition--the change response previously linked to temporally integrative updating of an ongoing auditory object--was strongly reduced, whereas the offset response was largely preserved and onset responses were only modestly affected. Critically, this modulation persisted during passive listening and was selectively amplified near the perceptual threshold during task-engaged detection, revealing an interaction between motor state and cognitive demand. Thus, natural locomotion does not uniformly degrade hearing; instead, it preferentially down-weights a behaviorally critical, temporally demanding stage of auditory processing, offering a framework for understanding how motor-cognitive state shapes auditory scene analysis in the moving brain.

neuroscience↗

bioRxiv2025

Role of DEPDC1 in Glioblastoma Malignant Phenotype and Radiosensitivity

Radiotherapy has significantly improved survival outcomes in glioblastoma (GBM) patients, particularly when combined with tumor resection and temozolomide chemotherapy. However, radioresistance remains a major obstacle, limiting further advances in prognosis and potential cure. DEPDC1, a gene implicated in various malignant phenotypes, has not yet been investigated for its role in GBM radioresistance, despite suggestive evidence from previous studies. In this study, analysis of the cancer database and GBM tissue microarrays revealed that DEPDC1 expression is significantly elevated in GBM tissues compared to normal brain tissues. Using GBM cell lines with DEPDC1 knockdown, we observed markedly reduced proliferation and motility. Notably, DEPDC1 downregulation significantly enhanced radiosensitivity, as demonstrated by increased radiation-induced apoptosis, G2/M phase arrest, DNA damage, and impaired DNA repair post-radiation, resulting in lower survival rates in clonogenic assays. Mechanistically, these effects may be mediated through DEPDC1-driven upregulation of NF-{kappa}B, supported by tumor sample analysis from our xenograft mouse model. Collectively, our findings suggest that DEPDC1 is not only involved in GBM malignancy but also represents a promising therapeutic target for overcoming radioresistance and developing effective radiosensitizers.

cancer biology↗

bioRxiv2025

Microbubble Backscattering Intensity Improves the Sensitivity of Three-dimensional (3D) Functional Ultrasound Localization Microscopy (fULM)

Functional ultrasound localization microscopy (fULM) enables brain-wide mapping of neural activity at micron-scale resolution but suffers from limited sensitivity due to sparse and noisy microbubble (MB) detections. Extending fULM into three dimensions (3D) further exacerbates these challenges because of low-frequency matrix arrays, reduced localization efficiency, and severe data sparsity. To address these limitations, we developed a statistical framework that models MB arrivals in 3D as a Poisson process accounting for localization efficiency, detection probability, and backscattered amplitude. This analysis predicts that integrating amplitude with count-based fULM improves functional sensitivity, particularly under high MB concentrations where localization saturates. Three-dimensional MB advection simulations confirmed these predictions, showing that backscattering fULM (B-fULM) maintains sensitivity at higher MB concentrations where conventional fULM fails. In rat brain experiments, B-fULM yielded stronger and more robust stimulus-evoked responses, with SNR gains of 18% in the somatosensory cortex and 61% in the thalamus, while preserving super-resolved spatial detail (33.4 m for B-fULM vs 35.7 m for fULM). These results establish B-fULM as a practical and sensitive approach for super-resolved 3D functional neuroimaging

bioengineering↗

bioRxiv2025

Light-field deep learning enables high-throughput, scattering-mitigated calcium imaging

Light field microscopy (LFM) enables volumetric, high throughput functional imaging. However, the computational burden and vulnerability to scattering limit LFMs application to neuroscience. We present a light-field strategy for volumetric, scattering-mitigated neural circuit activity monitoring. A physics-based deep neural network, LNet, is trained with two-photon volumes and one-photon light fields. A processing pipeline uses LNet to extract calcium activity from light-field videos of jGCaMP8f-expressing neurons in acute cortical slices. The extracted time series have high signal-to-noise ratios and reduced optical crosstalk compared to conventional volume reconstruction methods. Imaging 100 volumes per second, we observe putative spikes fired at up to 10 Hz and the spatial intermingling of putative ensembles throughout 530 x 530 x 100-micron volumes. Compared to iterative algorithms, LNet workflows reduce light-field video processing times by 2- to 12-fold, advancing the goal of real-time, scattering-robust volumetric neural circuit imaging for closed-loop and adaptive experimental paradigms.

bioengineering↗

bioRxiv2025

The TONSL-MMS22L complex and FANCM form an interdependent complex on chromatin to counter replication stress

FANCM is branchpoint DNA translocase essential for cellular response to replication stress. Here, we show that replication stress stimulates FANCM and the TONSL-MMS22L heterodimer bound to histones H3-H4 to form an interdependent complex on chromatin. TONSL-MMS22L recruits FANCM and Fanconi anemia (FA) core complex to stalled and collapsed forks, maintains FANCM on replication-stressed chromatin, promotes FANCD2 monoubiquitination, facilitates both repair and replication traverse of DNA interstrand crosslinks (ICLs), and suppresses sister chromatid exchanges, through its interactions with FANCM and H3-H4. Reciprocally, both DNA translocase activity and phosphorylation of FANCM facilitate recruitment of TONSL-MMS22L and RAD51 to perturbed forks. Moreover, TONSL-MMS22L and FANCM function together to promote activation of the FA pathway, ICL repair, homologous recombination and replication traverse. Cancer patients with tumors with wildtype FANCM and low expression of TONSL-MMS22L have a more favorable prognosis than those with high expression. Thus, FANCM-TONSL-MMS22L acts coordinately as a complex on chromatin that resolves replication stress, and this complex may present a therapeutic target for wildtype FANCM-linked cancer.

cell biology↗

bioRxiv2025

ZEB2 signaling is essential for ureteral smooth muscle cell differentiation and maintenance

Mowat-Wilson Syndrome (MWS) is a multiple congenital anomaly syndrome caused by mutations in the ZEB2, which plays a critical role in cell fate determination and differentiation during development. Congenital anomalies of the kidney and urinary tract (CAKUT) have been reported in MWS patients. However, the role of ZEB2 in urinary tract development and the cellular and molecular mechanism underlining the CAKUT phenotypes in MWS remains unknown. We performed ZEB2 protein expression analysis in the developing mouse ureter. We generated Zeb2 ureteral mesenchyme-specific conditional knockout mice by crossing Zeb2 floxed mice with Tbx18Cre mice (Zeb2 cKO) and analyzed the urinary tract phenotypes in Zeb2 cKO mice and wild-type littermate controls by gross and histological examination. Ureteral cellular and molecular phenotypes were studied using TAGLN, ACTA2, FOXD1, POSTN, CDH1, TBX18, and SOX9 ureteral cell-specific markers. We found that ZEB2 is expressed in TBX18+ ureteral mesenchymal cells during mouse ureter development. Deletion of Zeb2 in developing ureteral mesenchymal cells causes hydroureter and hydronephrosis phenotypes, leading to obstructive uropathy, kidney failure, and early mortality. Cellular and molecular marker analyses showed that the TAGLN+ACTA2+ ureteral smooth muscle cells (SMCs) layer is not formed in Zeb2 cKO mice at E15.5, but the FOXD1+ and POSTN+ tunica adventitia cells layer is significantly expanded compared to wild-type controls. CDH1+ urothelium cells are reduced considerably in the Zeb2 cKO ureters at E15.5. Mechanistically, we found that Zeb2 cKO mice have significantly decreased TBX18 expression but an increased SOX9 expression in the developing ureter at E14.5 and E15.5 compared to wild-type littermate controls. Our results show that ZEB2 is essential for ureter development by maintaining ureteral mesenchymal cell differentiation into normal ureteral SMCs. Our study also shed new light on the pathological mechanism underlying the developmental abnormalities of the urinary tract phenotypes in MWS patients. Author SummaryHydroureter and hydronephrosis are common congenital anomalies with high incidence (1:100 to 1:500) that can lead to obstructive uropathy and renal failure in the pediatric population. Mowat-Wilson Syndrome (MWS), caused by heterozygous mutations in the ZEB2 gene, is a genetic disease with multiple congenital developmental defects, including hydroureter and hydronephrosis. However, the molecular function of ZEB2 in ureter development and pathogenesis of hydroureter and hydronephrosis remains unknown. Here, we show that ZEB2 is expressed in the developing ureteral mesenchymal cells, and deletion of ZEB2 in ureteral mesenchymal cells leads to ureteral smooth muscle cell loss, which is replaced by tunica adventitia cells causing hydroureter and hydronephrosis phenotype. Hence, our work not only demonstrates the critical role of ZEB2 in ureter development but also provides molecular mechanisms of urinary tract anomalies in MWS patients.

developmental biology↗

bioRxiv2025

AMPK- and cGAS-Mediated Dual Sensing of Glucose and dsDNA Synergizes to Enhance Antitumor Immunity

Intratumoral glucose availability is linked considerably to tumor growth, immune evasion, and metastasis. However, the precise molecular mechanisms by which glucose levels govern cellular and immune responses against tumors remain incompletely understood. Here, we explored the context of tumors of intersections between AMP-activated protein kinase (AMPK) and cGAS-STING signaling, a key pathway initiating antitumor immunity. We unexpectedly found that AMPK activation robustly enhances cGAS-STING signaling within cancer and immune cells, which potently impacts melanoma and colorectal cell senescence, organoid apoptosis, and the infiltration of CD4+ and CD8+ T lymphocytes. Using classic or newly developed AMPK agonist Aldometanib, TBK1S511E/S511E knock-in (KI) mice, glucose metabolic modulator, as well as AMPK1/2 dKO melanoma, we demonstrated that dual sensing of intratumoral glucose and dsDNA integrated by the AMPK-TBK1 cascade is essential for initiating antitumor immunity and suppressing cancer progressions. Notably, novel AMPK agonists or intervening in glucose glycolysis by Lonidamine synergized effectively with STING agonists, substantially inhibiting melanoma growth. Therefore, these findings unravel a concise mechanism integrating glucose metabolism and innate DNA sensing into cancer cell fate and propose an effective therapeutic strategy to enhance antitumor immunity. HIGHLIGHTSO_LIDual and synergistic sensing of glucose and dsDNA facilitates antitumor immunity in melanoma and colorectal cancer; C_LIO_LIAMPK substitutes intratumoral cGAS-STING-IRF3 signaling through TBK1 phosphorylation at S511; C_LIO_LIGlucose deficiency induces cancer cell senescence, apoptosis, and T lymphocyte infiltration via the AMPK-TBK1 cascade; C_LIO_LINewly developed AMPK agonists synergize with STING agonists to retrieve striking tumor suppression. C_LI

cancer biology↗

bioRxiv2025

Improved Microbubble Tracking for Super-Resolution Ultrasound Localization Microscopy using a Bi-Directional Long Short-term Memory Neural Network

Ultrasound localization microscopy (ULM) enabled high-accuracy measurements of microvessel flow beyond the resolution limit of conventional ultrasound imaging by utilizing contrast microbubbles (MBs) as point targets. Robust tracking of MBs is an essential task for fast and high-quality ULM image reconstruction. Existing MB tracking methods suffer from challenging imaging scenarios such as high-density MB distributions, fast blood flow, and complex flow dynamics. Here we present a deep learning-based MB pairing and tracking method based on a bi-directional long short-term memory neural network for ULM. The proposed method integrates multiparametric MB characteristics to facilitate more robust and accurate MB pairing and tracking. The method was validated on a simulation data set, a tissue-mimicking flow phantom, and in vivo on a mouse and rat brain.

bioengineering↗

bioRxiv2024

Temporal Configuration as a New Feature of Sound: Psychological and Neurophysiological Evidence, Cross-species Consistency and Underlying Neuronal Mechanisms

Natural sounds are defined not only by their spectral content but also by their fine temporal structure. Here we show that millisecond-scale temporal configuration--defined by the ordering of inter-click intervals (ICIs) within a click train--behaves as a distinct auditory feature, conserved across species and emerging hierarchically along the auditory pathway. Human listeners reliably discriminated click trains that shared the same average ICI but differed in temporal configuration, and these differences elicited robust mismatch negativity (MMN) responses in an oddball paradigm, indicating automatic cortical deviance detection. Awake rats showed analogous MMN-like ECoG responses to configuration changes, demonstrating cross-species generality. Neuropixels recordings along the inferior colliculus-medial geniculate body-primary auditory cortex (IC-MGB-A1) axis revealed minimal configuration sensitivity in IC, intermediate sensitivity in MGB, and strong stimulus-specific adaptation to temporal configuration in A1. Reversible cooling of auditory cortex reduced configuration sensitivity in MGB, implicating corticothalamic feedback in shaping thalamic representations. Layer-resolved analyses further showed that supragranular A1 neurons carry stronger configuration-specific adaptation than infragranular neurons. These findings identify temporal configuration as a feature-like dimension of sound and delineate a hierarchical, feedback-dependent IC-MGB-A1 circuit architecture for encoding fine temporal structure in the mammalian brain.

neuroscience↗

bioRxiv2024

A signal of temporal integration in the human auditory brain: psychological insights, EEG evidence, and clinical application

Temporal integration, the process by which the auditory system combines sound information over a curtain period to form a coherent auditory object, is essential for coherent auditory perception, yet its neural mechanisms remain underexplored. We use a "transitional click train" paradigm, which concatenates two click trains with slightly differing inter-click intervals (ICIs), to investigate temporal integration in the human cortex. Using a 64-channel electroencephalogram (EEG), we recorded responses from 42 healthy participants exposed to regular and irregular transitional click trains and conducted change detection tasks. Regular transitional click trains elicited significant change responses in the human cortex, indicative of temporal integration, whereas irregular trains did not. These neural responses were modulated by ICI length, ICI contrast, and regularity. Behavioral data mirrored EEG findings, showing enhanced detection for regular conditions compared to irregular conditions and pure tones. Furthermore, variations in change responses were associated with decision-making processes. Temporal continuity was critical, as introducing gaps between click trains diminished both behavioral and neural responses. In clinical assessments, 22 coma patients exhibited diminished or absent change responses, effectively distinguishing them from healthy individuals. Our findings identify distinct neural markers of temporal integration and highlight the potential of transitional click trains for clinical diagnostics.

neuroscience↗

bioRxiv2024

Advanced deep-tissue imaging and manipulation enabled by biliverdin reductase knockout.

We developed near-infrared (NIR) photoacoustic and fluorescence probes, as well as optogenetic tools from bacteriophytochromes, and enhanced their performance using biliverdin reductase-A knock-out model (Blvra-/-). Blvra-/- elevates endogenous heme-derived biliverdin chromophore for bacteriophytochrome-derived NIR constructs. Consequently, light-controlled transcription with IsPadC-based optogenetic tool improved up to 25-fold compared to wild-type cells, with 100-fold activation in Blvra-/- neurons. In vivo, light-induced insulin production in Blvra-/- reduced blood glucose in diabetes by [~]60%, indicating high potential for optogenetic therapy. Using 3D photoacoustic, ultrasound, and two-photon fluorescence imaging, we overcame depth limitations of recording NIR probes. We achieved simultaneous photoacoustic imaging of DrBphP in neurons and super-resolution ultrasound localization microscopy of blood vessels [~]7 mm deep in the brain, with intact scalp and skull. Two-photon microscopy provided cell-level resolution of miRFP720-expressing neurons [~]2.2 mm deep. Blvra-/- significantly enhances efficacy of biliverdin-dependent NIR systems, making it promising platform for interrogation and manipulation of biological processes.

cell biology↗

bioRxiv2024

Combined Nanodrops Imaging and Ultrasound Localization Microscopy for Detecting Intracerebral Hemorrhage

ObjectiveAdvanced imaging methods are crucial for understanding stroke mechanisms and discovering effective treatments to reduce bleeding and enhance recovery. In preclinical in vivo stroke imaging, MRI, CT, and optical imaging are commonly used to evaluate stroke outcomes in rodent models. However, MRI and CT have limited spatial resolution for rodent brains, and optical imaging is hindered by limited imaging depth of penetration. Here we introduce a novel contrast-enhanced ultrasound imaging method to overcome these challenges and characterize intracerebral hemorrhage with unique insights. MethodsWe combined microbubble (MB)-based ultrasound localization microscopy (ULM) and nanodrop (ND)- based vessel leakage imaging to achieve simultaneous microvascular imaging and hemorrhage detection. ULM maps brain-wide cerebral vasculature with high spatial resolution and identifies microvascular impairments around hemorrhagic areas. NDs are sub-micron liquid-core particles which can extravasate due to blood-brain barrier (BBB) breakdown, serving as positive contrast agents to detect hemorrhage sites. ResultsOur findings demonstrate that NDs could effectively accumulate in the hemorrhagic site and reveal the location of the bleeding areas upon activation by focused ultrasound beams. ULM further reveals the microvascular damage manifested in the form of reduced vascularity and decreased blood flow velocity across areas affected by the hemorrhagic stroke. ConclusionThe results demonstrate that sequential ULM combined with ND imaging is a useful imaging tool for basic in vivo research in stroke with rodent models where brain-wide detection of active bleeding and microvascular impairment are essential.

bioengineering↗