Cellulose Nanofiber-Coated Perfluoropentane Droplets: Fabrication and Biocompatibility Study

A Novel Nanoscale Phase-Change Contrast Agent Evaluates the Hepatic Fibrosis Through Targeting Hepatic Stellate Cell Platelet-Derived Factor Beta Receptor by Ultrasound in Vitro

OBJECTIVE

As a reversible condition at its early stages, liver fibrosis can progress to cirrhosis and hepatocellular carcinoma, underscoring the importance of early detection for preventing severe outcomes and improving prognosis. To address this issue, we developed a platelet-derived growth factor receptor β (PDGFRβ)-targeted nanoscale phase-change contrast agent to target activated hepatic stellate cells (aHSC) and enable ultrasound imaging as a foundation for the early evaluation of liver fibrosis.

METHODS

PDGFR-β antibody-modified phase-change contrast agents (PPCAs) were synthesized utilizing film hydration and ultrasonic emulsification with perfluoropentane (PFP) encapsulated. PPCAs were specifically conjugated to aHSC with high PDGFR-β expression, whose targeting ability was evaluated using fluorescence confocal microscopy and flow cytometry. Phase transition at different temperatures and mechanical indices (MIs), as well as contrast-enhanced ultrasound imaging were analyzed.

RESULTS

PPCAs had an average diameter of 283.6 ± 11.3 nm with good dispersibility and relative stability, and the echo intensity increased correspondingly with increasing MIs. PPCAs exhibited both excellent biocompatibility and imaging ability when excited by high-frequency ultrasound set to an MI of 1.0 at 37°C, and simultaneously showed strong specific targeting ability to aHSC, with cellular uptake reaching 56.67 ± 5.96%.

CONCLUSION

As a new imaging avenue, PPCAs have the potential to enhance ultrasound imaging and establish the basis for diagnosis by targeting aHSC specifically with good biocompatibility and stability.

Acoustic Droplet Vaporization Efficiency and Oxygen Scavenging in Whole Blood

OBJECTIVE

Acoustic droplet vaporization (ADV) is the liquid-to-gas phase transition of perfluorocarbon (PFC) droplets to microbubbles upon ultrasound insonation. After ADV, gases dissolved in the surrounding fluid diffuse into microbubbles, enabling oxygen scavenging. Characterization of oxygen scavenging and transition efficiency (TE) in whole blood has so far been limited. In this work, oxygen scavenging and perfluorocarbon droplet TE in a saline buffer and whole bovine blood were evaluated using blood-gas analysis and flow cytometry.

METHODS

Oxygen scavenging from whole blood via ADV was determined using an in vitro flow phantom with droplets comprising a phospholipid shell and either a decafluorobutane (DFB) or a perfluoropentane (PFP) core. Fluorescent droplets were used to determine ADV TE in whole blood via flow cytometry. Finally, a mathematical model predicting oxygen scavenging from whole blood was developed based on the experimental TE values.

RESULTS

DFB droplets enabled greater oxygen scavenging and higher TE when compared with perfluoropentane droplets in both buffer and whole blood. Increasing the droplet concentration resulted in a greater amount of hemoglobin-bound and dissolved oxygen scavenging from whole blood. ADV of DFB droplets at a concentration of 5 × 10-4 mL/mL yielded a total oxygen reduction of 913 μM. The TE decreased with increasing droplet concentration in both buffer and whole blood. Experimental oxygen scavenging data in whole blood aligned with the predicted values from the mathematical model.

CONCLUSION

Increased oxygen scavenging and TE were achieved with DFB droplets relative to perfluoropentane droplets.

Novel perfluorocarbon-based oxygenation therapy alleviates Post-SAH hypoxic brain injury by inhibiting HIF-1α

In comparison to other stroke types, subarachnoid hemorrhage (SAH) is characterized by an early age of onset and often results in poor prognosis. The inadequate blood flow at the site of the lesion leads to localized oxygen deprivation, increased level of hypoxia-inducible factor-1α (HIF-1α), and triggers inflammatory responses and oxidative stress, ultimately causing hypoxic brain damage. Despite the potential benefits of oxygen (O2) administration, there is currently a lack of efficient focal site O2 delivery following SAH. Conventional clinical O2 supply methods, such as transnasal oxygenation and hyperbaric oxygen therapy, do not show the ideal therapeutic effect in severe SAH patients. The perfluorocarbon oxygen carrier (PFOC) demonstrates efficacy in transporting O2 and responding to elevated levels of CO2 at the lesion site. Through cellular experiments, we determined that PFOC oxygenation serves as an effective therapeutic approach in inhibiting hypoxia. Furthermore, our animal experiments showed that PFOC oxygenation outperforms O2 breathing, leading to microglia phenotypic switching and the suppression of inflammatory response via the inhibition of HIF-1α. Therefore, as a new type of O2 therapy after SAH, PFOC oxygenation can effectively reduce hypoxic brain injury and improve neurological function.