Scientific part:
We developed a strategy to prepare prototissues (or protocellular materials – PCMs) starting from binary populations of bio-orthogonally reactive protocells (proteinosomes) in oil. We developed the so-called "floating mould technique" allowing the bio-orthogonal ligation of the binary proteinosome population. With this technique it was possible to obtain PCM sheets that retain their compartmentalised structure and have a large (cm2) size. It was also possible to prepare PCMs patterned with different binary populations of proteinosomes within one layer of PCM by means of manual pipetting, and also stratified PCMs. Moreover, by encapsulating an established enzyme pair within the binary proteinosome population, we demonstrated and explored the protocell-protocell and protocell-environment communication within the same PCM and also in arrays of PCMs.
Subsequently, we developed a strategy to fabricate PCMs enhanced with a thermo- and photoresponsive polymer network enabling them to perform remotely controlled movements. The method consisted in the synthesis of two reactive copolymers capable to crosslink and form a network when mixed together. The two polymers were incapsulated and crosslinked in-situ in the aqueous lumen of the proteinosomes. The presence of the thermoresponsive polymer network significantly improved the mechanical properties of the PCM. These PCMs show thermoresponsive properties, reversibly shrinking to about 30 % of their initial area upon heating above 30 °C. Moreover, we also managed to encapsulate a light nano-absorber capable to convert visible light to heat, thus achieving a photo-contractile behaviour in the PCMs, observing a fast (within seconds) and reversible contraction upon shining light on them. Additionally, we developed non-thermoresponsive polymers allowing to make PCMs with patterns of photoresponsive and non-responsive protocells, thus achieving PCMs that could perform light-triggered anisotropic movements, such as bending.
We worked towards the implementation of emergent light-gated communication behaviours in PCMs. To do this, we encapsulate different enzymes within the thermo- and photoresponsive PCMs developed in the project. We demonstrated the possibility to obtain a thermally induced mechano-chemical transduction within the PCMs, following the observation of a reversible inhibition of the enzyme cascade reaction rate upon environmental temperature variation. Unfortunately, with the above-mentioned system it was not possible to successfully demonstrate the emergence of a photo-mechano-chemical transduction behaviour following a number of technical issues related to the light used to induce PCM movements. Nevertheless, research focussed at solving these issues is still ongoing within the Supervisor’s group and will hopefully lead to the expected results in the foreseeable future.
Communication, dissemination and exploitation of the results:
The key results of the project were disseminated using different channels. For the scientific audience, five scientific journal articles were published during the course of the fellowship. The publications were made open access. In addition to the above-mentioned publications, we expect to submit two more articles to top-tier scientific journals within the next few months, in order to disseminate the yet-unpublished findings obtained during the course of this fellowship. In addition to the publications, the results have been presented at two international scientific conferences. The results obtained from the research performed during this fellowship were also echoed and disseminated online through social media such as Facebook, Twitter and Instagram, or through the research group and the hosting institution’s websites.
