A Novel Non-Invasive Intervention for Removing Occlusions From Shunts Using an Abrading Magnetic Microswarm.

OBJECTIVE: Shunts are often employed as internal medical devices for draining aberrant fluids from organs. However, depositions of calcification in the shunt walls lead to its failure, requiring frequent replacements. The current surgical procedures for implanting shunts are invasive. METHODS: This paper introduces a novel, non-invasive approach for eliminating shunt deposits. In this non-invasive intervention, a swarm of magnetic nanoparticles (MNPs) guided by an external magnetic field removes the shunt deposition. A prototype device was fabricated to provide a proof of concept. MNPs were steered within the shunt channel containing calcification layers and successfully abraded the deposition layer. The proof-of-concept experiments used a moving magnetic field ranging from 0.1 to 0.3 T and a velocity between 1 to 12 cm/s. The average nanoparticles size was 45 nm. Five diverse contact theories predicted the amount of wear and indentation depth created by the abrading microswarm. RESULTS: Experimental results confirm that MNPs under a moving magnetic field can abrade shunt deposits. Also, there is a direct relation between the intensity of the magnetic field, the speed of magnet movement, and the rate of abrading the calcification deposits. The simulation results showed that the Hoeprich model deviated 12.1% from the experimental results and was the most suitable model. Conclusion & significance: This research has introduced a novel minimally invasive approach to remove shunt depositions that can reduce the number of revision surgeries and prevent surgical complications.

Study the effect of static magnetic field intensity on drug delivery by magnetic nanoparticles.

Employing the magnets in therapy has a long history of treating diseases, and currently new applications such as drug delivery by magnetic nanoparticles are gaining more attention. This research tried to study the effect of static magnetic field intensity on drug delivery by magnetic nanoparticles carrying thrombolytic agents. In this research, Fe3O4@SiO2 nanoparticles carrying streptokinase were applied. The efficiency of thrombolysis and micro-CT-scan images are utilized to study the effect of different magnetic fields (0.1, 0.2, 0.3 and 0.5 T) on thrombolysis. The results confirm that increasing the static magnetic field intensity accelerated the thrombolysis. Increasing the intensity of the magnetic field from 0.1 to 0.3 T leads to an increase in clot dissolution rate from 55 to 89%, respectively. Moreover, micro-CT-scan images revealed that magnetic nanoparticles carrying a thrombolytic agent penetrated deeper into the mesh-like structure of clot as the magnetic field intensities increased, which could lead to further dissolution of the clot.

Noninvasive thrombectomy of graft by nano-magnetic ablating particles.

Artificial vascular treatment is an emerging interdisciplinary subject of medicine. Although the use of artificial vessels has led to many successful advancements, blood clotting remains a major challenge, especially in terms of mural clots created along the vessel wall that do not completely block the vessel. The main objective of this study is to present a method for declotting artificial vessels. This research introduces a novel thrombectomy technique in artificial vessels by employing nano-magnetic particles under a rotating magnetic field to remove mural clots in artificial vessels. A mathematical model describes the relationship between process parameters. In vitro tests confirm the feasibility of nano-magnetic thrombectomy in cleaning and declotting artificial vessels. The results show that the clot fragments are nano-sized, which eliminates the risk of distal emboli as a concern of using current atherectomy techniques. Meanwhile, no damage to the artificial vessels is observed. The results show that the frequency of rotating the magnetic field has the greatest effect on clot removal. The conceptual principles stated in this study also have the potential to be used in other vascular depositions, such as the accumulation of lipids, and calcification atherosclerosis.

In Vitro Evaluation of Capturing and Dissolving the Clot by Magnetic Nanoparticles Carrying a Thrombolytic Agents Instead of Temporary Inferior Vena Cava (IVC) Filter.

This study aims to evaluate the efficiency of a novel in vitro technique in clot capturing and dissolving them by applying magnetic force on magnetic nanoparticles (MNP) carrying thrombolytic agents. It is a quick and simple method to protect patients from a life-threatening pulmonary embolism in an emergency to provide time for the medical team. To analyze the in vitro efficiency of nano-magnetic capturing and dissolving of clots (NCDC), different levels of process parameter including strength magnetic field (0.1, 0.2 and 0.3 T) and fluid flow rate (2.5, 5 and 7 l/min) are exposed to different blood clots sizes from 5 × 10 to 20 × 10 mm² (length × diameter), in an in vitro flow model. The results show that by increasing the parameters to their maximum values, it is possible to immobilize 100% of the clots and dissolve around 61.4% of clots weight. In addition, the clot-dissolving is directly proportional to the magnetic field strength. NCDC is an efficient technique in immobilizing and dissolving the clots and its efficiency depends on process parameters especially the magnetic field.