Biological semiconductors or semiconducting in biology?

Discussion in 'General Science & Technology' started by Glassbeadgame, Jan 30, 2017.

  1. Glassbeadgame Registered Member

    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

    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.
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  3. exchemist Valued Senior Member

    Fascinating. But a bit dense for the average reader. Can you explain a bit more about the photo-CDNIP effect in photosynthesis? I'm not sure I quite follow it.
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  5. Glassbeadgame Registered Member

    There are a number of articles on the solid state photo-CIDNP effect and photosynthesis out there e.g But you are right that this area of science needs to have some 'Plain English' techniques applied to it overall - there seems to be an expectation that readers will already been expert in what has been a very niche field. Perhaps materials scientists could help with that.

    Since writing the above post I found other articles (see links below) that seem related to what I have outlined - but for some reason seems to have missed some obvious links to findings in quantum biology - as set out in my initial post.

    - 'Quantum criticality in the origin of life'
    - A New Ab Initio Approach to the Development of High Temperature Superconducting Materials.
    - Towards room temperature solid state quantum devices at the edge of quantum chaos for long living quantum states.

    Maybe new articles covering all the above points are written by the same authors as this is a fast developing field.

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  7. rpenner Fully Wired Staff Member

    Since you are incapable of explaining about the photo-CDNIP effect in photosynthesis, should staff delete this thread as one empty of intellectual engagement and discussion?
  8. origin Trump is the best argument against a democracy. Valued Senior Member

    If the author does not supply an explanation after your nudge, then by all means lock the thread. The links are there if anyone wants them.
  9. exchemist Valued Senior Member

    Look, you have no business posting stuff here that you can't either explain or at least comment intelligently on in your own words. We can all look things up on the internet for ourselves. It looks to me as you are just cutting and pasting bits and pieces without understanding them. That is pretty useless on a discussion forum.
  10. Glassbeadgame Registered Member

    Sorry, I didn't realise this post would create so much criticism or that there was a requirement to explain all the concepts used in post in detail when that information exists elsewhere.
    Last edited: Feb 6, 2017
  11. Glassbeadgame Registered Member

    I am a non scientist who has asked a specific question and attempted to start an discussion on this - including adding some information and hyperlinks which I thought might be useful. I think I have annoyed some of the senior users who are assuming I should have more knowledge of this area of science. I would like the moderator to delete this post because I have not been clear enough, and do not what to create more upset. I realise that it is very difficult for a non scientist to generate discussion around such a complex area and I think I should stay away from science forums and as many people seem to feel that all science is the preserve of scientists. It has been difficult for me to understand this as in my field (s) everyone is allowed to join in discussions - but I have come to understand that science is operates in a very specific and disciplined way - even when it is just being 'chatty'. Sorry for causing any problems, and thank you for your understanding. I wont sign back on to this site, so I will leave this in the moderators capable hands.
  12. rpenner Fully Wired Staff Member

    We have several troublesome posters who troll the forum in various ways, including making deceitful claims to scientific understanding beyond their ken and only giving their posts a facade of actual fact-based discussion. Certain factors associated with your 3 posts seem to suggest you are similarly inclined and may be a recently banned-poster:
    • Time of registration.
    • Lack of a paragraph explaining a basis for conversation or motivation for exploration of the topic. What's your educational and research background? As presented you come across as a dilettante intent on cutting and pasting links followed on a science news aggregator. // Edit. Post #8 confirms this interpretation.
    • Facile summaries of the work of others replacing exposition of one's original thought.
    • Deflection when pressed for details of concepts and theories vital to talk intelligently on one's own choice of topic. Post #3 was a second chance to actually demonstrate your behavior was not just pretense to understanding the articles. // Edit. In Post #8 you admit you did not understand the material, rendering posts #1, #3, #7 as intellectually dishonest.
    • Deflection when called to account to common standards (norms) of behavior. This thread is your entire history here, unless you are a persistent plague on Sci Forums, so you should be cautious, as with any new social situation, to be certain you are abiding by local rules and norms.
    • Deflection when called to carry one's own burden. The fact that information exists doesn't mean it can be found or that it exists in a form suitable for this discussion and certainly doesn't mean you have that information which is required to make sense of the articles you cite. Your topic, your burden.
    • Private details captured by the forum software
    Last edited: Feb 6, 2017
  13. rpenner Fully Wired Staff Member

    What is your specific question? The thread title is about organic semiconductors. It has a question mark but is not a question. Many of your OP links are unrelated to the thread title.

    If you have no history here, why would you value our input? Why are there no questions in the body of the original post (OP)? Where are the hooks in the OP which would allow us to build on your understanding of the topic? Now we learn you have no background in the sciences so an answer in the jargon of material science, quantum chemistry, etc would not be useful to you.

    Your topic, your burden. To assume a posture of understanding the articles you cite is intellectually dishonest and kills any potential conversation.

    You admit it is a complex area, but did not carry your burden to 1) delineate the actual area and 2) write the background information on the topics of interest (possibly specific biological molecules and definitions of semiconductors, but not even you seem to know) 3) use that background information to formulate a specific question you wanted input on.

    What "field(s)" would that be? Every field of human thought has necessary background knowledge. One doesn't go to a Game of Thrones discussion board and ask "What's Game of Thrones and why doesn't my toy store carry it?" If you can't explain to trained professionals in physics and chemistry what a Photo-CDNIP is in context, then all of your links are exposed as deceitful shams, window dressing for your pretense to knowledge. Such a mean-spirited, intellectually dishonest approach is what murdered the discussion.

    Are these discussions that you refer to held online? This isn't twitter, this isn't live conversation. You had the time to compose your list of links, so you should have had the time to write a coherent paragraph giving your backstory and requesting help. The links do nothing to advance any conversation because none of them are used to support any of your positions. Now that we've established that you lack the background to read those articles, they are exposed as time-wasting digressions when wasting other people's time is an abuse of forum hospitality.

    This passive-aggressive deflection of criticism fails to take proper responsibility for your own tactless and possibly bad behavior.
    Last edited: Feb 6, 2017
  14. exchemist Valued Senior Member

    No, you have not asked a specific question. The only question mark I can see is in the title, which is not a sentence and does not contain a decipherable question. What you have done is post a load of highly technical guff, copied from elsewhere and which you now admit (much later) you don't yourself understand, with no question or useful comment of your own. What is the point of that?

    I'm quite sure there is an interesting discussion to be had about whether there are any parallels between some aspects of semiconductor behaviour and some of the electron transport processes in biochemistry. But we are not going to get that by your approach to the subject so far.

    Do you want to try again, with a clear question or issue this time and a link, say not more than one or two references, that you think relate to it?

    By the way, have you read much Hermann Hesse?
    Last edited: Feb 7, 2017

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