scholarly journals Ultrasound Doppler-guided real-time navigation of a magnetic microswarm for active endovascular delivery

2021 ◽  
Vol 7 (9) ◽  
pp. eabe5914 ◽  
Author(s):  
Qianqian Wang ◽  
Kai Fung Chan ◽  
Kathrin Schweizer ◽  
Xingzhou Du ◽  
Dongdong Jin ◽  
...  
Keyword(s):  
Blood Flow ◽  
Real Time ◽  
Targeted Delivery ◽  
Ex Vivo ◽  
Dynamic Environments ◽  
Doppler Imaging ◽  
Great Promise ◽  
Mean Velocity ◽  
Ultrasound Doppler ◽  
Flowing Blood

Swarming micro/nanorobots offer great promise in performing targeted delivery inside diverse hard-to-reach environments. However, swarm navigation in dynamic environments challenges delivery capability and real-time swarm localization. Here, we report a strategy to navigate a nanoparticle microswarm in real time under ultrasound Doppler imaging guidance for active endovascular delivery. A magnetic microswarm was formed and navigated near the boundary of vessels, where the reduced drag of blood flow and strong interactions between nanoparticles enable upstream and downstream navigation in flowing blood (mean velocity up to 40.8 mm/s). The microswarm-induced three-dimensional blood flow enables Doppler imaging from multiple viewing configurations and real-time tracking in different environments (i.e., stagnant, flowing blood, and pulsatile flow). We also demonstrate the ultrasound Doppler–guided swarm formation and navigation in the porcine coronary artery ex vivo. Our strategy presents a promising connection between swarm control and real-time imaging of microrobotic swarms for localized delivery in dynamic environments.

Pulpal Blood Flow Measurement with Ultrasound Doppler Imaging

2010 ◽  
Vol 36 (3) ◽  
pp. 419-422 ◽  
Author(s):  
Min-Jung Yoon ◽  
Euiseong Kim ◽  
Seoung-Jong Lee ◽  
Young-Min Bae ◽  
Sergey Kim ◽  
...  
Keyword(s):  
Blood Flow ◽  
Flow Measurement ◽  
Doppler Imaging ◽  
Blood Flow Measurement ◽  
Ultrasound Doppler ◽  
Pulpal Blood Flow

Correlation of γ-radioactivity and Scanning Electron Microscopy in measurement of retention of 111Indium-labeled canine endothelial cells on synthetic vascular grafts

1989 ◽  
Vol 47 ◽  
pp. 886-887
Author(s):  
E.J. Prendiville ◽  
S. Laliberté Verdon ◽  
K. E. Gould ◽  
K. Ramberg ◽  
R. J. Connolly ◽  
...  
Keyword(s):  
Blood Flow ◽  
Ex Vivo ◽  
Vascular Grafts ◽  
Retention Data ◽  
Vascular Prostheses ◽  
Group 4 ◽  
Human Fibronectin ◽  
Insufficient Time ◽  
Group 3 ◽  
Group 2

Endothelial cell (EC) seeding is postulated as a mechanism of improving patency in small caliber vascular grafts. However the majority of seeded EC are lost within 24 hours of restoration of blood flow in previous canine studies . We postulate that the cells have insufficient time to fully develop their attachment to the graft surface prior to exposure to hemodynamic stress. We allowed EC to incubate on fibronectin-coated ePTFE grafts for four different time periods after seeding and measured EC retention after perfusion in a canine ex vivo shunt circuit.Autologous canine EC, were enzymatically harvested, grown to confluence, and labeled with 30 μCi 111 Indium-oxine/80 cm 2 flask. Four groups of 5 cm x 4 mm ID ePTFE vascular prostheses were coated with 1.5 μg/cm.2 human fibronectin, and seeded with 1.5 x 105 EC/ cm.2. After seeding grafts in Group 1 were incubated in complete growth medium for 90 minutes, Group 2 were incubated for 24 hours, Group 3 for 72 hours and Group 4 for 6 days. Grafts were then placed in the canine ex vivo circuit, constructed between femoral artery and vein, and subjected to blood flow of 75 ml per minute for 6 hours. Continuous counting of γ-activity was made possible by placing the seeded graft inside the γ-counter detection crystal for the duration of perfusion. EC retention data after 30 minutes, 2 hours and 6 hours of flow are shown in the table.

1618: Real-Time Monitoring of Nitric Oxide and Blood Flow During Ischemia-Reperfusion in the Rat Testis

2006 ◽  
Vol 175 (4S) ◽  
pp. 521-521
Author(s):  
Motoaki Saito ◽  
Tomoharu Kono ◽  
Yukako Kinoshita ◽  
Itaru Satoh ◽  
Keisuke Satoh
Keyword(s):  
Nitric Oxide ◽  
Blood Flow ◽  
Real Time ◽  
Ischemia Reperfusion ◽  
Real Time Monitoring ◽  
Rat Testis

Lutein Complex Supplementation Increases Ocular Blood Flow Biomarkers in Healthy Subjects

2019 ◽  
Vol 89 (1-2) ◽  
pp. 5-12
Author(s):  
Alon Harris ◽  
Brent Siesky ◽  
Amelia Huang ◽  
Thai Do ◽  
Sunu Mathew ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Diastolic Blood Pressure ◽  
Healthy Subjects ◽  
Ocular Blood Flow ◽  
Capillary Blood ◽  
Post Treatment ◽  
Capillary Blood Flow ◽  
Doppler Imaging ◽  
Retinal Capillary

Abstract. Introduction: To investigate the effects of a lutein complex supplementation on ocular blood flow in healthy subjects. Materials and Methods: Sixteen healthy female patients (mean age 36.8 ± 12.1 years) were enrolled in this randomized, placebo-controlled, double-blinded, two-period crossover study. Subjects received daily an oral dose of the lutein with synergistic phytochemicals complex (lutein (10 mg), ascorbic acid (500 mg), tocopherols (364 mg), carnosic acid (2.5 mg), zeaxanthin (2 mg), copper (2 mg), with synergistic effects in reducing pro-inflammatory mediators and cytokines when administered together in combination) and placebo during administration periods. Measurements were taken before and after three-week supplementation periods, with crossover visits separated by a three-week washout period. Data analysis included blood pressure, heart rate, intraocular pressure, visual acuity, contrast sensitivity detection, ocular perfusion pressure, confocal scanning laser Doppler imaging of retinal capillary blood flow, and Doppler imaging of the retrobulbar blood vessels. Results: Lutein complex supplementation produced a statistically significant increase in mean superior retinal capillary blood flow, measured in arbitrary units (60, p = 0.0466) and a decrease in the percentage of avascular area in the superior (−0.029, p = 0.0491) and inferior (−0.023, p = 0.0477) retina, as well as reduced systolic (−4.06, p = 0.0295) and diastolic (−3.69, p = 0.0441) blood pressure measured in mmHg from baseline. Data comparison between the two supplement groups revealed a significant decrease in systemic diastolic blood pressure (change from pre- to post-treatment with lutein supplement (mean (SE)): −3.69 (1.68); change from pre- to post-treatment with placebo: 0.31 (2.57); p = 0.0357) and a significant increase in the peak systolic velocity (measured in cm/sec) in the central retinal artery (change from pre- to post-treatment with lutein supplement: 0.36 (0.19); change from pre- to post-treatment with placebo: −0.33 (0.21); p = 0.0384) with lutein complex supplement; data analyses from the placebo group were all non-significant. Discussion: In healthy participants, oral administration of a lutein phytochemicals complex for three weeks produced increased ocular blood flow biomarkers within retinal vascular beds and reduced diastolic blood pressure compared to placebo.

Development and Evaluation of Particulate Microcarriers of Adapalene as a Topical Delivery System

2019 ◽  
Vol 9 (3) ◽  
pp. 222-233
Author(s):  
Divya D. Jain ◽  
Namita D. Desai
Keyword(s):  
Patient Compliance ◽  
Targeted Delivery ◽  
Ex Vivo ◽  
Acne Vulgaris ◽  
Drug Loading ◽  
Topical Therapy ◽  
Skin Irritation ◽  
Topical Delivery ◽  
Diffusion Method ◽  
Topical Gel

Background: Adapalene is a promising third generation retinoid used in the topical treatment of acne vulgaris. However, the major drawback associated with conventional topical therapy of Adapalene is the ‘retinoid reaction’ which is dose-dependent and characterized by erythema, scaling and burning sensation at the application sites. Microparticulate drug delivery can play a major role in reducing side effects and providing better patient compliance due to targeted delivery. Methods: Adapalene microparticles were prepared using quasi emulsion solvent diffusion method. The effects of formulation variables including polymer ratios, amounts of emulsifier, drug loading and process variables such as stirring time and speed on the physical characteristics of microparticles were investigated. The developed microparticles were characterized by DSC and SEM. Adapalene microparticles were incorporated into Carbopol 971 NF gel for ease of topical delivery. Results: Adapalene microparticulate topical gel showed sustained drug release over 8 hours in in vitro studies. The amount of drug retained in the rat skin during ex vivo studies was higher in the microparticulate topical gel (227.43 ± 0.83 µg/cm2) as compared to the marketed formulation (81.4 ± 1.11 µg/cm2) after 8 hours indicating localized and sustained drug action that can be useful in treating acne vulgaris. The safety of optimized Adapalene gel determined by skin irritation studies performed on Sprague Dawley rats showed no irritation potential. Conclusion: Microparticles can provide promising carrier systems to deliver Adapalene, improving patient compliance due to enhanced skin deposition, localized and sustained action with reduced associated irritant effects.

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