First, I developed a method for high throughput synthesis of cell-like hydrogel microparticles, which allows synthesis of microgels of any desired shape. The shape defines the structure of the self-assembly in a similar way as shapes of individual Lego brick defines the structure of an object one builds from those. I found conditions, under which the microgel particles self-assemble into ordered two dimensional structures (Figure1-left). I developed method to ‘glue’ the individual discs of the assembly together and form one sheet. By tuning the conditions of the gluing, the sheet either remains flat, or buckles to a bowl shape or a roll (Figure 1-right), thus sheets of various desired shapes can be easily produced to fulfill the requirements of a specific application. Because the assembled structure contains voids between individual discs, the resulting sheet contains also voids — pores. The developed method provides convenient synthesis of hydrogel sheets with defines pore sizes through self-assembly. In collaboration with researchers from the Department of Pharmaceutical Sciences we work on application of these highly defined porous membranes as supports for kidney cells with future application in the manufacture of artificial kidney. This collaboration already led to a joint publication on the SFL synthesis of biodegradable microgels.
Presented self-assembled membranes, constructed from responsive hydrogels, can work as actuators and are promising in soft-microrobotics, artificial muscle construction or hybrid hydrogel-living systems. Thanks to the self-assembly, such actuators can be built remotely for example in inaccessible areas.
The ability to build ordered structures through self-assembly of hydrogel microparticles opened a way to self-assembled organized hydrogel structures, however the complexity of available structures is limited. Therefore, I focused on alternative ways of organizing microscaled hydrogels. I developed hydrogel microrobots, that crawl over a solid surface and manipulate other microobjects in a controlled manner. The locomotion principle of the developed crawlers is fundamentally new, allowing simple driving and steering of the crawler with visible light. Due to their soft hydrogel nature, these robots can be used for precise manipulation with mechanically sensitive objects for example in single cell analysis or in-vitro fertilization techniques. I plan to use these crawlers as microscopic builders of organized hydrogel structures (Figure 2). I am convinced, that the combination of demonstrated self-assembly and directed assembly principles is the key for simple, affordable yet precise construction of hydrogel structures, organized on microscale, currently needed (among others) in tissue engineering applications.
Overview of the dissemination and explotation of the results:
List of conferences attended: CHAINS 2016 – Poster presentation, Soft Matter Meeting 2017 – Oral presentation, LIQUIDS 2017 – Poster presentation, Micromotors Dresden 2017 – Poster presentation, Utrecht Chemistry Days 2017 – Poster presentation (best poster award), IACIS 2018 – Oral presentation (confirmed)
The work on biodegradable microgels, acknowledging the EC funding was published in the Small journal (Jimp = 8.6).
Rehor, I.; van Vreeswijk, S.; Vermonden, T.; Hennink, W. E.; Kegel, W. K.; Eral, H. B. Biodegradable Microparticles for Simultaneous Detection of Counterfeit and Deteriorated Edible Products. Small 2017, 13 (39).
The fulltext can be find in the open repository of the Utrecht University: (
https://www.narcis.nl/publication/RecordID/oai%3Adspace.library.uu.nl%3A1874%2F358594/id/2/Language/EN/uquery/rehor/coll/publication(öffnet in neuem Fenster))
The research was highlighted on the cover of the journal and in the following media: Advanced Science, TU Delft website, De Ingenieur, NPT, University of Utrecht website
At least two more publications are planned, one on the soft microrobots (manuscript is almost ready and the submission is expected in several weeks) and one on self-assembled membranes (experimental work is ready). Separate publication on the coupling of translational-rotational motion of Brownian microgels is also expected (data analysis in progress).
