Editorial for the Special Issue 'Synthetic Biology and Biomimicry'.

The Special Issue ‘Synthetic Biology and Biomimicry’ in Small features invited and contributed reports within this broad interdisciplinary field. This collection of original reports and reviews is a follow-up effort to the Special Issue ‘Artificial Biology: Molecular Design and Cell Mimicry',[1] which was published mid 2020 on the pages of this journal. Both of these Special Issues are publishing events to accompany the conference ‘ArtBio2022 – Artificial Biology: Molecular Design and Cell Mimicry', which was originally scheduled for 2020 at Aarhus University in Denmark, but only took place in 2022 due to the Covid-19 crisis. Many of the authors who contributed to the current Special Issue were also present at the conference. It was an event that highlighted the interdisciplinary nature of artificial biology (aka bottom-up synthetic biology, biomimicry), showcasing the current state-of-the-art in several sub-disciplines feeding this field while identifying new and largely unexplored avenues for future developments. The collection of articles in this special issue covers diverse subjects that cover length scales from atoms and molecules over nano-sized assemblies to artificial cells, discussing fundamental aspects and emerging applications for various nature-inspired mimics. On the molecular level, a research article from the Chandrawati lab discusses generation of an endogenous gasotransmitter, nitric oxide, using polymeric amines.[2] On the nanoscale, Wang, Liu, Wei et al. reviewed the treatment modalities for cardio- and cerebrovascular diseases enabled by nanozymes.[3] Bui, Haupt et al. provided an overview over molecularly imprinted polymers as synthetic antibodies.[4] Nucleic acids as a construction material and tool in nanotechnology are presented in several reports. Saccà et al. review the production and utility of self-assembled artificial DNA nanocompartments.[5] Further, Margulies et al. outline the possibilities to equip bacteria with new properties via the modification of the bacterial cell surfaces with DNA structures.[6] Ricci, Gothelf et al. present DNA-antibody conjugates that use biomolecular recognition to perform protein template reactions.[7] Zaburdaev, Göpfrich et al. approach the challenge of division of synthetic cells and investigate segregation of DNA within cellular mimics.[8] Andersen et al. report on the co-transcriptional assembly of RNA into nanostructures with stabilizing geometries.[9] Ryckelynck et al. develop innovative RNA-based biosensors.[10] Several reports pertain to the sub-field of artificial motion and in particular nano/micromotors, which are objects that exhibit self-propulsion outperforming Brownian motion. de Dios Andres and Städler report on the migration of keratinocytes in floating paper based cell culture chips assisted by micromotors.[11] Wan, Mao, Zhou et al. demonstrate nitric oxide powered nanomotors that are engineered for enhanced drug delivery and towards treatment of atherosclerosis.[12] The biomimicking behavior of colloidal microswimmers is reviewed by Simmchen et al.[13] Cho et al. outline the state-of-the-art, the production methods, and the biological applications of nano/microreactors as mimics to cellular life.[14] From a different perspective, mimicking motion at the micro- and millimeter scale is a core aim in soft robotics. In this context, Lagerwall et al. report the continuous flow microfluidic production of liquid crystal elastomer-based actuators.[15] Artificial cells was a subject of several reports addressing different challenges and opportunities. For instance, Han et al. develop artificial cells that contain cyanobacteria, to harvest energy from light and perform the synthesis of glucose using CO2 as a carbon source.[16] Housecroft, Palivan et al. assemble catalytic subcompartments to perform cascade enzymatic reactions, as a mimic of signaling cascades in natural cells.[17] Liu, Ha et al. develop a heterodimeric protein to engineer artificial interfaces between cells, synthetic or natural.[18] De Greef, Kostiainen et al. investigate protocells as scavengers for heparin.[19] Wegner et al.[20] report on light-dependent adhesion phenomena in artificial membranes and synthetic cells. As guest editors of this special issue and co-organizers of the ArtBio2022 conference, we sincerely hope that both the physical event and this collection of articles contribute to the development and promotion of the exciting, fundamentally important field of bottom-up synthetic biology. The authors declare no conflict of interest.