I have been reading research on biological semiconductors recently. Charge transport has been found in a variety of naturally-derived small molecule, semiconducting biological compounds e.g carotenoids (produced by plants and bacteria). There has been interest in such biological materials as the polyconjugated structure of this class of compounds suggests that the natural electronic activity of derivatives could be repurposed as an active semiconductor material for organic electron devices. Meredith Muskovich 2012. Semiconductors are also being used in technology aiming to mimic biology e.g artificial photosynthesis. The idea of biological semiconductors itself is not a new one. As far back as 1938 Jordan and in 1941 Szent-Györgyi suggested that proteins might possess the nature of semiconductors (L I Boguslavskii 1970). But there seems to have been no research into whether biological materials may be acting in a similar way to semiconductors, as part of biological function. So I have looked into this myself and here is a summary of what I have found. - PJ Hore has pointed out that certain organic semiconductors (OLEDs) exhibit magnetoelectroluminescence or magnetoconductance, the mechanism of which shares essentially identical physics with radical pairs in biology. If you want to see the full article on this click on https://phys.org/news/2016-06-radical-pair-analysis-hurdle-theory.html Radical pairs mechanisms in biology are theorised to be triggered by a flavoprotein called a cryptochrome. It is of interest then that organic molecules that serve as chromophores (of which flavins such as cryptochrome, are examples) consist of extended conjugated π-systems, which allow electronic excitation by sunlight and provide photochemical reactivity. Eukaryotic riboflavin-binding proteins typically bind riboflavin between the aromatic residues of mostly tryptophan- and tyrosine-built triads of stacked aromatic rings…Ultrafast electron transfer mechanisms from an aromatic moiety to a photoexcited flavin are not only observed for riboflavin-binding proteins but for other flavoproteins, like for BLUF (blue light sensing using FAD) domains, cryptochromes, and DNA photolyases. H Staudt 2012. Both cryptochromes and photolayses are flavoproteins that undergo ultrafast charge separation upon electron excitation of their flavin cofactors. In biology, evidence has also been found that the existence of central aromatic acids can serve as stepping stones to support an electron hopping mechanism (W Sun 2015) - including in flavins. And it has been evidenced that there are cases of semiconducting biological materials (e.g carotenoids) being utilised in natural photosynthesis, as well as evidence of photosynthetic reaction centres ultilising ultra-fast electron transfer, singlet and triplet states,and quantum coherence. N Lambert 2012 In photosynthetic reaction centres, it has been noted that there seems to be a link between the conditions of the unsurpassed efficient light-induced electron transfer in photosynthetic reaction centres and occurrence of a solid state photo-CIDNP (see J Matysik 2009 and I F Cespedes-Camacho and J Matysik 2014). And a solid state Photo-CIDNP effect has also been demonstrated on the photochemical yield of a flavin-tryptophan radical pair in Escherichia coli photolyase. K B Henbest 2008, and a mutant of the bluelight photoreceptor phototropin (LOV1-C57S from Chlamydomonas reinhardtii). S S Thamarath 2010. In the same way that photo-CIDNP MAS NMR has provided detailed insights into photosynthetic electron transport in reaction centres, it is anticipated in a variety of applications in mechanistic studies of other photoactive proteins. It may be possible to characterize the photoinduced electron transfer process in cryptochrome in detail. W Xiao-Jie12016. One of the main benefits such states seem to offer biology is protection against antioxidants. R Van Grondelle has suggested that during photosynthesis, plants use electronic coherence for ultrafast energy and electron transfer and have selected specific vibrations to sustain those coherences. In this way photosynthetic energy transfer and charge separation have achieved their amazing efficiency. At the same time these same interactions are used to photoprotect the system against unwanted byproducts of light harvesting and charge separation at high light intensities. Also see G S Orf 2015 and A Marais 2015. Freeman W Cope (1975) reviewed the evidence for solid state physical processes in diverse biological systems. He found that semiconduction of electrons across the enzyme particles as the rate-limiting process in cytochrome oxidase is suggested by the peculiar kinetic patterns of this enzyme and by microwave Hall effect measurements. He also found that: PN junction conduction of electrons was suggested by kinetics of photobiological free radicals in eye and photosynthesis; superconduction at physiological temperatures could be involved in growth and nerve; and phonons and polarons might be involved in mitochondrial phosphorylation. E D Giudice (1989) made the proposal of coherent electromagnetic processes as the engine for biological dynamics suggests that Josephson effects could be present in living cells and claimed that there was evidence for this. And it has been proposed that the quantum like transition that realizes the stable state of living matter at room temperature is similar to the non conventional BCS-like transition as seen in high Tc superconductors.(N Poccia 2009). Frohlich proposed a theory in which biomolecules with higher electric dipole moment lie up along the actin filaments immediately beneath the cell membrane, and electric dipole oscillators propagate along each filament as coherent waves without thermal loss – just as in the case of superconducting media. H Frohlich 1968, 1970 and 1975. The idea of biological superconductors operating in nature may seem even more far fetched than biological semiconductors being used within biology - but then it has been found that the quantum mechanical hydrogen tunnelling associated with enzymatic C-H bond cleavage provides a unique window into the necessity of protein dynamics for achieving optimal catalysis. Experimental findings support a hierarchy of thermodynamically equilibrated motions that control the H-donor and -acceptor distance and active-site electrostatics, creating an ensemble of conformations suitable for H-tunnelling. J P Klinman 2013. Maybe it is time researchers working on the field of quantum biology got together with materials scientists to discuss the possible implications of the above findings.