New biodegradable nanomotors for biomedical applications

By July 3, 2020January 4th, 2021IBEC

Researchers at the Institute for Bioengineering of Catalonia (IBEC), a BIST centre, are part of an international collaboration that has published a paper in Nano Letters describing the engineering and functionality of a biocompatible and biodegradable nanomotor. This hybrid structure, composed of an organic exterior, propels itself using inorganic nanoparticles acting as an engine.

The research was led by Jan van Hest and Laoi Abdelmohsen from the Institute of Complex Molecular Systems at TU/e (ICMS) in collaboration with Samuel Sánchez from the Institute for Bioengineering of Catalonia (IBEC, a BIST centre) in Barcelona, as well as researchers based in China and the UK.

An emerging area in biomedicine that is currently being explored is the use of motorised, biocompatible, and biodegradable particles that shuttle drugs to diseased tissue. Nanomotors are molecular or nanoscale devices that can move through a biological medium by converting chemical energy into motion and can be used for the delivery of pharmaceutical drugs to specific parts of the body. Now researchers from ICMS at Eindhoven University of Technology (TU/e) along with researchers from IBEC (a BIST centre), the Soochow University, and Swansea University have developed a new synthesis approach for biodegradable nanomotors where inorganic nanoparticles stored in the nanomotors help propel them. This study has been published in the journal Nano Letters.

Innovative nanomotor
The innovative hybrid nanomotor is composed of a structure called a stomatocyte, also known as poly(ethylene glycol)-block-poly(D,L-lactide) (PEG−PDLLA), which is loaded with manganese dioxide – the engine for the nanomotor. The PDLLA block copolymer stomatocytes are bowl-shaped cells and have a hollow inner cavity with a small opening to the external environment. Previous research had demonstrated the ability of these particles to confine and protect and engine or fuel within the cavity, which can then be catalysed to drive movement through complex biological environments. As a proof-of-principle, researchers demonstrated effective tumor penetration of the hybrid nanomotors, showing that these engineering nanomotors can retain their functionality within biological contexts and they show potential for biomedical applications.

Engine synthesised in the nanomotor
The present work offers a novel approach where the manganese dioxide engine is synthesised inside the stomatocyte nanomotor. When this inorganic-based engine reacts with hydrogen peroxide, it creates nanobubbles of oxygen that are expelled from the small opening of the stomatocyte, and thus propels the structure in the opposite direction. Hydrogen peroxide, which is toxic to cells, is highly expressed in tumor microenvironments. The stomatocytes can also be reused once the engine inside their cavity remains functional, and if not in use, the engine does not “escape” from the opening even after a period of three months.

The hybrid structure described is fully biocompatible and biodegradable, due to its organic exterior. Moreover, the nanomotors described could be employed as multimodal platforms and there is potential to control the particles remotely with external cues (for example magnetic fields or light). In other words, these new hybrid compounds exhibit the best features of inorganic and organic nano-architectures. This study paves the way for further exploration of autonomous nanomotors and their numerous potential applications in biomedicine.

More information can be found on the IBEC website