Photosymbiosis for Biomedical Applications

Abstract

Without the sustained provision of adequate levels of oxygen by the cardiovascular system, the tissues of higher animals are incapable of maintaining normal metabolic activity, and hence cannot survive. The consequence of this evolutionarily suboptimal design is that humans are dependent on cardiovascular perfusion, and therefore highly susceptible to alterations in its normal function. However, hope may be at hand. “Photosynthetic strategies,” based on the recognition that photosynthesis is the source of all oxygen, offer a revolutionary and promising solution to pathologies related to tissue hypoxia. These approaches, which have been under development over the past 20 years, seek to harness photosynthetic microorganisms as a local and controllable source of oxygen to circumvent the need for blood perfusion to sustain tissue survival. To date, their applications extend from the in vitro creation of artificial human tissues to the photosynthetic maintenance of oxygen-deprived organs both in vivo and ex vivo , while their potential use in other medical approaches has just begun to be explored. This review provides an overview of the state of the art of photosynthetic technologies and its innovative applications, as well as an expert assessment of the major challenges and how they can be addressed.

Green oxygen power plants in the brain rescue neuronal activity

“…Although such a reaction appears to be inevitable in the case of pathogenic single-celled prokaryotes and eukaryotes, certain microorganisms such as C. reinhardtii or Synechocystis 6803 might form a favorable exception. For instance, a lack of systemic immune response has been demonstrated when transplanting an algae scaffold onto the skin of mice ( Chávez et al., 2020 ; Schenck et al., 2015 ). Moreover, injection of these green algae into zebrafish eggs formed chimeras that remained viable for several days and after subsequent extraction from the larvae, the algae continued to grow ( Alvarez et al., 2015 ).…”

“…In fact, natural symbiotic interactions between such microorganisms and animals are reported for members of the phyla Porifera (sponges), Cnidaria (corals, sea anemones; Venn et al., 2008 ) and also salamander species ( Burns et al., 2020 ; Kerney et al., 2011 ). By mimicking this natural principle, microalgae have occasionally been employed in biomedical science as efficient O 2 source, mostly to supplant absent blood perfusion of isolated tissue ( Chávez et al., 2020 ). This culminated in a tissue-engineered co-culture of the microalga Chlamydomonas reinhardtii and fibroblasts to form a dermal scaffold that facilitates healing of skin wounds in mice through photosynthetic O 2 production ( Hopfner et al., 2014 ) or in the case of Synechococcus elongatus in a photon-powered myocardium of the ischemic heart ( Cohen et al., 2017 ).…”

What can biofabrication do for space and what can space do for biofabrication?

“…Novel concepts and ideas are therefore awaited. Some of these ideas are the use of mesodermal progenitor cells [84], engineered human embryonic stem cells ectopically expressing human ETS variant 2 [85], modified lab-on-chip systems [86], or even using photosynthetic strategies [87]. Figure I depicts the overall process of mature organ generation from the building blocks (cell source, biomaterials, and scaffolds), through 3D bioprinting, vascularization, continuous monitoring, and, finally, organ maturation.…”

“…It is possible to fabricate ad hoc nutrients and currently efforts to engineer meat have gained a lot of momentum [66,67]. Beyond food, the use of vegetal forms of life with specific properties, such as production of energy and oxygen, has also been shown to be feasible [68,69]. Ultimately, we could also foresee the use of biofabrication technologies to make 3D in vitro models to study bacteria and virus infections in space, on one side to understand the risks of bringing Earth species on other planets and, on the other, serving as a possible testbed to be better prepared in the distant future for testing new viruses found on new planets (Figure 3).…”

A Photosynthetic Animal: A Sacoglossan Sea Slug that Steals Chloroplasts

“…The feasibility of constructing artificial photosynthetic animal cells is increased by using sequencing tools with high speed, low cost, and high throughput, and genome modification tools such as CRISPR-Cas9 systems. Artificial photosynthetic animal cells are expected to contribute to medical fields with applications in cancer treatment and photosynthetic therapy using oxygen evolution (Wang et al 2019, Chávez et al 2020.…”