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Light Driven Stomatocyte Nanomotors

Periodic Reporting for period 1 - LIMO (Light Driven Stomatocyte Nanomotors)

Reporting period: 2018-06-01 to 2020-05-31

The discovery of first centimeter-sized chemical motors has brought great interest in the field of catalytic micro/nanomotors fabrication. Nanomotors are mostly produced via top-down approaches, are micron sized and contain hard metal surfaces, which are not suitable for biomedical applications and soft robotics. Also, the bottleneck for such nanomotors is use of toxic fuels which are both not biocompatible and quest to gain control over the directional movement and speed of the nanomotors, hence, limiting its biomedical applications. To overcome aforementioned problems, their is a need to fabricate nanomotors that can use light as an energy source for driving nano-assemblies and to gain control over attributes like direction and speed that has not been explored before. Three main scientific objectives were proposed in the grant, the work carried out towards the achievement is listed below:
• Objective 1: Synthesis and assembly of stomatocytes using PEG-b-PS block copolymers functionalised with azocompounds.
• Objective 2: Fabricate thylakoid loaded nanomotor and compare its movement with azocompounds functionalised nanomotor.
• Objective 3: Combining azocompounds functionalised and thylakoid loaded stomatocytes into one system to use both UV and Visible light source.

During the fellowship objective 1 and 2 were met without any deviations, but due to stability issues objective 3 was not met and hence a new WP was designed and the objectives of those were met. In brief, for all the objectives polymers were synthesized and used as such to fabricate stomatocytes structures. In case of objective 1, the azobenzene molecules were grafted onto pre-formed stomatocytes with functional handles and tested for its motility in presence of UV-Vis light source and studied for its phototactic behaviour. For objective 2, the TNP were encapsulated into the stomach of stomatocytes during their shape transformation from polymersomes into stomatocytes and visible light was used to study the motion behaviour under different light intensities. In terms of the new objective 3, CaCO3 nanoparticles were grown in-situ by adding Na2CO3 to the pre-formed CaCl2 loaded stomatocytes and tested for its ability to power motion in presence of acidic pH, together with studying its pH tactic behaviour.

I envision, the as fabricated nanomotors to be optimised for biomedical applications like cargo delivery and tumor sensing with improved control on attributes like speed and directionality. They could also be advantageous in the field of soft robotics and sensing “hormone disruptors” that is toxic to human health. They can also play crucial role in formulation of self-healing materials.
In the fellowship, light and pH driven nanomotors were fabricated and exploited for biomedical applications for the latter nanomotor. The results from WP1 is currently under review in Nature Communications which is an open access journal. For WP2, the results have been published in Advanced Intelligent Systems (open access) and we were also able to secure inside cover for the same. In terms of modified WP3, the results are under review in Nanoscale. During the tenure I was also able to publish a review article in Journal of Materials Chemistry B, which is due to be accepted soon.

In terms of collaborative work, I was able to publish a second author paper in ACS Nano which has open access. All the publications resulting from this fellowship includes reference of the EU funding. Apart from this the results were also disseminated in conferences in FMS, DPD and in intra department Symposiums that involved both poster and oral presentation.

In terms of outreach activities, I was invited to give a lecture at UMC Utrecht for students who are looking for innovation internship projects which will also be a stepping stone for collaborative work between Radboud University and UMC Utrecht. Lab tours to Masters and Bachelor’s students was also given to enlighten them with the research activities being carried out in the department. Together with this, I also attended the MCAA General Assembly Annual Conference in Vienna to highlight the research activities of the host institution.
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