Towards imaging of medical microbots

Date

Mar 5, 2019

Time

1:00 PM - 2:00 PM

Speaker

Azaam Aziz

Affiliation

IFW Dresden

Language

en

Main Topic

Materialien

Other Topics

Materialien, Physik

Host

Kristina Krummer-Meier

Description

Miniature technologies, like medical microbots, could revolutionize many fields of medicine by enabling non-invasive diagnosis, drug-delivery and therapeutic procedures. As explained recently by our research group, microbots must clear two major hurdles to enter clinical trials: visualization and control inside the body [1]. Researchers are trying to improve microbot imaging strategies to achieve better resolution and sensitivity. For example, Bradley et al. demonstrated controlled swimming of a swarm of around 10.000 artificial bacterial flagella (ABFs) in a mouse using fluorescence imaging [2]. Sarthak et al. could track the trajectory of a trail of bubbles from fast-moving microjets using ultrasound in a water batch containing hydrogen peroxide [3], and Martel et al. reported the visualization of a cluster of magnetotactic bacteria (5X107 bacterial count per mL) using magnetic resonance imaging (MRI) in a 1.5 mL Progene microtube [4]. So far, different imaging techniques have been explored but they are still too coarse for single-microbot imaging. In radiology, nuclear medicine and X-rays employ hazardous radiation and contrast agents. Likewise, MRI can resolve structures with submillimeter resolution and in some cases offering temporal resolutions in the milliseconds range but demands expensive infrastructure and continuous presence of strong magnetic fields. To overcome some of these limitations, we explored the use of two types of optical imaging techniques. First, we developed a customized infrared imaging (IR) setup which operates in the first biological window to visualize mobile microstructures under phantom tissues using the principle of light reflection. The technique shows advantages such as the possibility to resolve microstructures down to 20 µm in diameter and their real time tracking under phantom tissues, without using any labels. The second optical approach combines the advantages of ultrasound such as penetration depth and real-time imaging with the molecular specificity of optical techniques, also called optoacoustic imaging. This technique was used to track conical microtubes with 100 µm length in three dimensions and in real time. With this technique we lose spatial resolution but gain on penetration depth This achievement is of great importance for the visualization of dynamic processes that occur at the microscale, and in particular, for the tracking and control of emerging technologies such as medical microbots, micro-catheters and in general of small medical tools. [1] M. Medina-Sánchez and O. G. Schmidt, Nature, vol. 545, no. 7655, pp. 406–408, (2017) [2] A. Servant et al., Adv. Mater., vol. 27, no. 19, pp. 2981–2988, (2015) [3] A. Sánchez et al., Proc. IEEE RAS EMBS Int. Conf. Biomed. Robot. Biomechatronics, pp. 169–174, (2014) [4] O. Felfoul et al., Annu. Int. Conf. IEEE Eng. Med. Biol. Soc. EMBC’10, vol. 1, pp. 4367–4370, (2010)

Links

• Seminars at the IFW

Last modified: Mar 5, 2019, 1:07:01 AM