Final Report Summary - CHIRALMICROBOTS (Chiral Nanostructured Surfaces and Colloidal Microbots)
The ERC project “Chiral Nanostructured Surfaces and Colloidal Microbots” (ChiralMicrobots) has achieved major results in the fabrication of nanostructured surfaces and nanocolloids, the actuation of micro- and nanostructures in fluids, including in biomedically-relevant fluids and tissues, and fundamental aspects of swimming at low Reynolds numbers.
A nanofabrication method has been developed that combines a fast, parallel nanopatterning method (block-copolymer micelle nanolithography) with the physical vapor glancing angle deposition (GLAD) method to grow unique, designer nanostructures on entire wafers. The work has been published in Nature Materials. This “nanoGLAD” method has allowed the growth of the smallest, uniform chiral 3D structures that have been grown to date. Sonication can be used to detach the nanostructures, which can be as small as 50nm (and as large as 4 microns) from the surface, such that they can be used as nanocolloids in solution. The nanostructures include chiral helical structures, which serve as propellers. The growth method is fast, as it is a parallel bottom-up technique, and in a few hours more than one hundred billion nanostructures can be grown. Cooling of the substrate permits the growth of 3D nanostructures with plasmonic metals. Remarkably, it could be shown in Nature Communication publication that the inclusion of non-precious metals, together with Ag, in combination with a chiral shape leads to structures that show record surface plasomon resonance (LSPR) signals – surpassing the results from all other LSPR sensing papers to date. The inclusion of a magnetic material during the growth permits the actuation of the chiral, plasmonic structures with a magnetic field and the spectroscopic observation of their orientation even in strongly absorbing blood samples. This permitted the use of the chiral nanopropellers for nanorheological measurements.
Much of the work under this ERC grant concerned the actuation and swimming of micro- and nanopropellers and structures at low Reynolds numbers. A particular focus were real tissues and biomedically important fluids. The fundamental modes of locomotion that can be used for swimming at low Reynolds number were studied. This allowed us to demonstrate the first microscallop that can swim with a reciprocal, symmetric motion, thereby circumventing limitations set by the scallop theorem. The work has been published in Nature Communications. It is an important, general result as it concerns the design of swimming structures in non-Newtonian fluids. Another achievement has been the realization of the smallest microswimmer that has been demonstrated to date, which has been published in Nature Materials.
The locomotion of ChiralMicrobots has been studied in detail. Several modes of propulsion including magnetic and chemically-propelled structures (chiral and achiral) have been made and studied as part of this ERC project. One focus has been the locomotion of the ChrialMicrobots through biomedical fluids and tissues. Propellers that are smaller than any swimming microorganism were grown using the nanoGLAD method and they could be steered through the macromolecular network of tissue-like gels. It was also demonstrated that the use of enzymes enables the penetration of the ChiralMicrobots through mucus. These results received much media attention and are, together with the microscallop and the smallest microswimmer to date, pioneering results in the field of microswimmers and microrobotics. Finally, the actuation of the ChiralMicrobots initiated a new research program on acoustic effects.
A nanofabrication method has been developed that combines a fast, parallel nanopatterning method (block-copolymer micelle nanolithography) with the physical vapor glancing angle deposition (GLAD) method to grow unique, designer nanostructures on entire wafers. The work has been published in Nature Materials. This “nanoGLAD” method has allowed the growth of the smallest, uniform chiral 3D structures that have been grown to date. Sonication can be used to detach the nanostructures, which can be as small as 50nm (and as large as 4 microns) from the surface, such that they can be used as nanocolloids in solution. The nanostructures include chiral helical structures, which serve as propellers. The growth method is fast, as it is a parallel bottom-up technique, and in a few hours more than one hundred billion nanostructures can be grown. Cooling of the substrate permits the growth of 3D nanostructures with plasmonic metals. Remarkably, it could be shown in Nature Communication publication that the inclusion of non-precious metals, together with Ag, in combination with a chiral shape leads to structures that show record surface plasomon resonance (LSPR) signals – surpassing the results from all other LSPR sensing papers to date. The inclusion of a magnetic material during the growth permits the actuation of the chiral, plasmonic structures with a magnetic field and the spectroscopic observation of their orientation even in strongly absorbing blood samples. This permitted the use of the chiral nanopropellers for nanorheological measurements.
Much of the work under this ERC grant concerned the actuation and swimming of micro- and nanopropellers and structures at low Reynolds numbers. A particular focus were real tissues and biomedically important fluids. The fundamental modes of locomotion that can be used for swimming at low Reynolds number were studied. This allowed us to demonstrate the first microscallop that can swim with a reciprocal, symmetric motion, thereby circumventing limitations set by the scallop theorem. The work has been published in Nature Communications. It is an important, general result as it concerns the design of swimming structures in non-Newtonian fluids. Another achievement has been the realization of the smallest microswimmer that has been demonstrated to date, which has been published in Nature Materials.
The locomotion of ChiralMicrobots has been studied in detail. Several modes of propulsion including magnetic and chemically-propelled structures (chiral and achiral) have been made and studied as part of this ERC project. One focus has been the locomotion of the ChrialMicrobots through biomedical fluids and tissues. Propellers that are smaller than any swimming microorganism were grown using the nanoGLAD method and they could be steered through the macromolecular network of tissue-like gels. It was also demonstrated that the use of enzymes enables the penetration of the ChiralMicrobots through mucus. These results received much media attention and are, together with the microscallop and the smallest microswimmer to date, pioneering results in the field of microswimmers and microrobotics. Finally, the actuation of the ChiralMicrobots initiated a new research program on acoustic effects.