Intelligent Systems
Note: This research group has relocated.


2021


Magnetic Micro-/Nanopropellers  for Biomedicine
Magnetic Micro-/Nanopropellers for Biomedicine

Qiu, T., Jeong, M., Goyal, R., Kadiri, V., Sachs, J., Fischer, P.

In Field-Driven Micro and Nanorobots for Biology and Medicine, pages: 389-410, 16, (Editors: Sun, Y. and Wang, X. and Yu, J.), Springer Nature, November 2021 (inbook)

Abstract
In nature, many bacteria swim by rotating their helical flagella. A particularly promising class of artificial micro- and nano-robots mimic this propeller-like propulsion mechanism to move through fluids and tissues for applications in minimally-invasive medicine. Several fundamental challenges have to be overcome in order to build micro-machines that move similar to bacteria for in vivo applications. Here, we review recent advances of magnetically-powered micro-/nano-propellers. Four important aspects of the propellers – the geometrical shape, the fabrication method, the generation of magnetic fields for actuation, and the choice of biocompatible magnetic materials – are highlighted. First, the fundamental requirements are elucidated that arise due to hydrodynamics at low Reynolds (Re) number. We discuss the role that the propellers’ shape and symmetry play in realizing effective propulsion at low Re. Second, the additive nano-fabrication method Glancing Angle Deposition is discussed as a versatile technique to quickly grow large numbers of designer nano-helices. Third, systems to generate rotating magnetic fields via permanent magnets or electromagnetic coils are presented. And finally, the biocompatibility of the magnetic materials is discussed. Iron-platinum is highlighted due to its biocompatibility and its superior magnetic properties, which is promising for targeted delivery, minimally-invasive magnetic nano-devices and biomedical applications.

link (url) DOI [BibTex]

2021

link (url) DOI [BibTex]


Slippery micropropellers penetrate the vitreous humor
Slippery micropropellers penetrate the vitreous humor

Wu, Z., Qiu, T., Fischer, P.

(US20210170056A1), 2021 (patent)

Abstract
Microparticles actively propel through the vitreous humour and reach the retina in porcine eyes. The slippery micro helical propellers are constructed by the combination of glancing angle deposition technique and the fusion of the slippery liquid layer. The magnetically propulsion in the vitreous humour relies on the matched size of the propeller to the collagen network of the vitreous, and the anti-adhesion coating of the collagen fiber bundles. Clinical optical coherence tomography observed the displacement of the slippery micropropellers through the vitreous to the macular area on the retina. The slippery micropropellers realize the controllable massive movements to the retina in 30 mins, while exerting the travelling distance of above one centimeter. The injection of the slippery micropropellers, the magnetically-powered controllable propulsion in the vitreous, and the optical coherence tomography imaging technique, constitute an intact method for rapid targeted ocular delivery, providing a promising approach towards ophthalmologic applications.

[BibTex]


Magnetic field generator
Magnetic field generator

Qiu, T., Fischer, P.

(US20210228298A1), 2021 (patent)

Abstract
A magnetic field generator that comprises at least three groups of magnets, the magnetic moment of each magnet being rotatable about a rotation axis, wherein each group comprises at least two magnets, and each group has an orientation in the sense that the rotation axes of the magnetic moments of the magnets of the same group extend in the group's orientation. The orientations of the different groups are linearly independent.

[BibTex]

[BibTex]

2020


Propeller and method in which a propeller is set into motion
Propeller and method in which a propeller is set into motion

Qui, T., Fischer, P.

(US20200031010A1), 2020 (patent)

Abstract
A method where a propeller is set into locomotion relative to a medium at least partially surrounding the propeller. An actuator induces a rotation of the propeller relative to the medium and about a rotational axis of the propeller, and the propeller converts its rotational movement into locomotion relative to the medium. The aspect ratio of at least one cross-section of the propeller is three or more. Also a helical or modifiedly helical propeller for converting rotational movement of the propeller into locomotion of the propeller relative to a medium at least partially surrounding the propeller, where the aspect ratio of at least one cross section of the propeller is three or more. And a method of producing a propeller, including the step of providing a plate extending along the helical axis, where the aspect ratio of at least one cross section of the plate is three or more.

[BibTex]


A conjugate complex facilitating the transport of a cargo through a medium
A conjugate complex facilitating the transport of a cargo through a medium

Rothenstein, D., Bill, J., Fischer, P.

(US20200215202A1), 2020 (patent)

Abstract
The present invention relates to conjugate complexes, comprising at least one biological entity, at least one cargo moiety, and at least one effector moiety that is capable of converting, degrading, and/or modifying a given medium, wherein the at least one cargo moiety and the at least one effector moiety are directly or indirectly coupled to the biological entity. The present invention further relates to uses thereof and methods for facilitating the transport of a cargo moiety through a given medium.

[BibTex]

[BibTex]


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Soft Microrobots Based on Photoresponsive Materials

Palagi, S.

In Mechanically Responsive Materials for Soft Robotics, pages: 327-362, (Editors: Koshima, Hideko), Wiley-VCH, Weinheim, 2020 (incollection)

DOI [BibTex]

DOI [BibTex]


Method of producing a phantom and phantom
Method of producing a phantom and phantom

Qiu, T., Fischer, P.

(US10573201B2), 2020 (patent)

Abstract
The present invention relates to a method of producing a phantom resembling a human or animal organ or tissue, the phantom comprising at least one first region having at least one tissue like property and at least one cavity having a plurality of hollow branches connected thereto, with at least some of the plurality of hollow branches being formed such that they project into the first region having tissue like properties. The invention further relates to a method of making the first structure and to a corresponding phantom.

[BibTex]

2019


Method and apparatus for fabricating a component
Method and apparatus for fabricating a component

Melde, K., Fischer, P.

(EP3034281B1), 2019 (patent)

Abstract
The invention relates to a method of fabricating a component having a one-, two- or three-dimensional geometry, wherein the shape of the component is obtained by utilizing an acoustic field and the effect of acoustic forces and by fixating a shape that forms in the acoustic field. This may be achieved by accumulating a material, like e. g. discrete particles in the pressure nodes formed by the acoustic field. Furthermore, the invention relates to an apparatus for fabricating a component, including an acoustic source device for forming an acoustic field that gives rise to a shape, including shapes formed by a particle distribution by acoustic forces, and a fixation device for fixating a shape of the particle distribution. Applications of the invention are available in the fields of fabricating materials with arbitrary shapes, e.g. for rapid prototyping purposes, and the assembly of materials.

[BibTex]


Method of assessing the performance of a human or robot carrying out a medical procedure and assessment tool
Method of assessing the performance of a human or robot carrying out a medical procedure and assessment tool

Qiu, T., Adams, F., Miernik, A., Fischer, P.

(US20190130791A1), 2019 (patent)

Abstract
The present invention relates to method of assessing the performance of a human or robot carrying out a medical procedure by using a phantom resembling a human or animal organ or tissue and to an assessment tool comprising such a phantom.

[BibTex]

2018


Nanoscale robotic agents in biological fluids and tissues
Nanoscale robotic agents in biological fluids and tissues

Palagi, S., Walker, D. Q. T., Fischer, P.

In The Encyclopedia of Medical Robotics, 2, pages: 19-42, 2, (Editors: Desai, J. P. and Ferreira, A.), World Scientific, October 2018 (inbook)

Abstract
Nanorobots are untethered structures of sub-micron size that can be controlled in a non-trivial way. Such nanoscale robotic agents are envisioned to revolutionize medicine by enabling minimally invasive diagnostic and therapeutic procedures. To be useful, nanorobots must be operated in complex biological fluids and tissues, which are often difficult to penetrate. In this chapter, we first discuss potential medical applications of motile nanorobots. We briefly present the challenges related to swimming at such small scales and we survey the rheological properties of some biological fluids and tissues. We then review recent experimental results in the development of nanorobots and in particular their design, fabrication, actuation, and propulsion in complex biological fluids and tissues. Recent work shows that their nanoscale dimension is a clear asset for operation in biological tissues, since many biological tissues consist of networks of macromolecules that prevent the passage of larger micron-scale structures, but contain dynamic pores through which nanorobots can move.

link (url) DOI [BibTex]

2018

link (url) DOI [BibTex]


Ultrasonic actuator device and applications thereof
Ultrasonic actuator device and applications thereof

Qiu, T., Fischer, P.

(US10008960B2), 2018 (patent)

Abstract
ltrasonic actuator device (100) includes actuator arm arrangement (10) including first and second actuator sections (11,12), wherein the first section is arranged for coupling with support structure (50) and the second section is movable relative to the first section, and ultrasonic driver device (20) including at least one ultrasonic driver unit (21-28) coupled with at least one of first and second sections for driving actuator arm arrangement (10) and for providing movement of the second section relative to the first section, and wherein actuator arm arrangement (10) is movable with at least two degrees of freedom and the at least one ultrasonic driver unit includes an array of oscillating elements being arranged for creating an acoustic stream in an adjacent medium in response to application of ultrasound. Furthermore, an operational instrument including at least one ultrasonic actuator device (100) and a method of using the device are described.

Project Page [BibTex]


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Nanorobots propel through the eye

Wu, Z., Troll, J., Jeong, H., Qiang, W., Stang, M., Ziemssen, F., Wang, Z., Dong, M., Schnichels, S., Qiu, T., Fischer, P.

Max Planck Society, 2018 (mpi_year_book)

Abstract
Scientists at the Max Planck Institute for Intelligent Systems in Stuttgart developed specially coated nanometer-sized robots that could be moved actively through dense tissue like the vitreous of the eye. So far, the transport of such nano-vehicles has only been demonstrated in model systems or biological fluids, but not in real tissue. Our work constitutes one step further towards nanorobots becoming minimally-invasive tools for precisely delivering medicine to where it is needed.

link (url) [BibTex]

link (url) [BibTex]


Apparatus and method for creating a holographic ultrasound field in an object
Apparatus and method for creating a holographic ultrasound field in an object

Melde, K., Weber, P., Fischer, P.

(US20180341221A1), 2018 (patent)

Abstract
An ultrasonic apparatus (100) for creating a holographic ultrasound field (1) comprises an ultrasound source device (10) being adapted for creating an ultrasound wave, and a transmission hologram device (20) having a transmission hologram (21) and an exposed acoustic emitter surface (22), said transmission hologram device (20) being acoustically coupled with the ultrasound source device (10) and being arranged for transmitting the ultrasound wave through the acoustic emitter surface (22) and creating the holographic ultrasound field in a surrounding space, wherein the acoustic emitter surface (22) is a smooth surface which do not influence the field distribution of the ultrasound wave. Furthermore, a method of creating a holographic ultrasound field in an object (3), wherein the ultrasonic apparatus (100) is used, and applications of the ultrasonic apparatus (100) are described.

[BibTex]

2017


Chapter 8 - Micro- and nanorobots in Newtonian and biological viscoelastic fluids
Chapter 8 - Micro- and nanorobots in Newtonian and biological viscoelastic fluids

Palagi, S., (Walker) Schamel, D., Qiu, T., Fischer, P.

In Microbiorobotics, pages: 133 - 162, 8, Micro and Nano Technologies, Second edition, Elsevier, Boston, March 2017 (incollection)

Abstract
Swimming microorganisms are a source of inspiration for small scale robots that are intended to operate in fluidic environments including complex biomedical fluids. Nature has devised swimming strategies that are effective at small scales and at low Reynolds number. These include the rotary corkscrew motion that, for instance, propels a flagellated bacterial cell, as well as the asymmetric beat of appendages that sperm cells or ciliated protozoa use to move through fluids. These mechanisms can overcome the reciprocity that governs the hydrodynamics at small scale. The complex molecular structure of biologically important fluids presents an additional challenge for the effective propulsion of microrobots. In this chapter it is shown how physical and chemical approaches are essential in realizing engineered abiotic micro- and nanorobots that can move in biomedically important environments. Interestingly, we also describe a microswimmer that is effective in biological viscoelastic fluids that does not have a natural analogue.

link (url) DOI [BibTex]

2017

link (url) DOI [BibTex]

2016


Method for encapsulating a nanostructure, coated nanostructure and use of a coated nanostructure
Method for encapsulating a nanostructure, coated nanostructure and use of a coated nanostructure

Jeong, H. H., Lee, T. C., Fischer, P.

(WO2016156148A1), 2016 (patent)

Abstract
The present invention relates to a method for encapsulating a nanostructure, the method comprising the steps of: -providing a substrate; -forming a plug composed of plug material at said substrate; -forming a nanostructure (on or) at said plug; -forming a shell composed of at least one shell material on external surfaces of the nanostructure, with the at least one shell material covering said nanostructure and at least some of the plug material,whereby the shell and the plug encapsulate the nanostructure. The invention further relates to a coated nanostructure and to the use of a coated nanostructure.

link (url) [BibTex]

2014


Convertor
Convertor

Fischer, P., Mark, A.

May 2014 (patent)

[BibTex]

2014

[BibTex]

2010


Magnetic Nanostructured Propellers
Magnetic Nanostructured Propellers

Fischer, P., Ghosh, A.

July 2010 (patent)

[BibTex]

2010


NONLINEAR OPTICAL PROPERTIES OF CHIRAL LIQUIDS Electric-dipolar pseudoscalars in nonlinear optics
NONLINEAR OPTICAL PROPERTIES OF CHIRAL LIQUIDS Electric-dipolar pseudoscalars in nonlinear optics

Fischer, P., Champagne, B.

In NON-LINEAR OPTICAL PROPERTIES OF MATTER: FROM MOLECULES TO CONDENSED PHASES, 1, pages: 359-381, Challenges and Advances in Computational Chemistry and Physics, 2006 (incollection)

Abstract
We give all overview of linear and nonlinear optical processes that can be specific to chiral molecules in isotropic media. Specifically, we discuss the pseudoscalars that underlie nonlinear optical activity and chiral frequency conversion processes in fluids. We show that nonlinear optical techniques open entirely new ways of exploring chirality: Sum-frequency-generation (SFG) at second-order and BioCARS at fourth-order arise in the electric-dipole approximation and do not require circularly polarized light to detect chiral molecules in solution. Here the frequency conversion in itself is a measure of chirality. This is in contrast to natural optical activity phenomena which are based on the interference of radiation from induced oscillating electric and magnetic dipoles, and which are observed as a differential response to right and left circularly polarized light. We give examples from our SFG experiments in optically active solutions and show how the application of an additional static electric field to sum-frequency generation allows the absolute configuration of the chiral solute to be determined via all electric-dipolar process. Results from ab initio calculations of the SFG pseudoscalar are presented for a number of chiral molecules

[BibTex]

[BibTex]