Social programme: Fellows' research weekend on 'Smart Structures'

The study of insect sex pheromones has contributed many extremely powerful chemical tools for manipulating insect behaviour. Although this includes both pests and beneficial insects, there has been relatively limited practical value in terms of pest management or conservation. The lepidopterous sex pheromones, which have received most attention, are powerful attractants but only for the male insects. The first identification of aphid sex pheromones and the first sex related pheromones for haematophagous insects, including mosquitoes and sandflies, opened up new possibilities but practical value has still been difficult to realise. The chemical synthesis is complicated by very strict stereochemical requirements and sustained delivery is hampered by high volatility and chemical instability. It has long been considered possible to overcome such problems eventually by using GM to produce the pheromone, for example from a crop to be defended against insect attack, and this has been technically achieved for the aphid alarm pheromone in wheat. However, although the behavioural impact on aphids and their parasites was impressive in the lab, the precise conditions for response were not achieved in field trials. Another group of signal chemicals or semiochemicals, in addition to the pheromones, that is now showing promise relates to host recognition and location. Indeed, by delivery from companion plants in agricultural situations operating with low external inputs such as is necessary for small holder farming in sub-Saharan Africa, plant stress related semiochemicals can control insect pests including the fall armyworm currently causing havoc in the region. Similar stress related semiochemistry is now showing promise for protection of farm animals from insect-vectored pathogens. These host derived semiochemicals may also be developed more effectively by GM technologies in ongoing studies.

Nano to macro-scale, synthetic or natural; particles can have unique forms engineered by nature or humans, and yet their shapes are often determined by their environments. At one extreme synthetic particles comprising structures with hierarchical shells can be described as being coated by grass-like fats and trees, where their shapes are distorted by the phases of matter they exist. Nanosculpting can create new “Janus”, “Saturn” and “Boojum” supermolecules, which can have potential applications in optical filters and meta-materials. At the other extreme, nature provides us with a vast array of unique monodisperse and potentially anisotropic particles based on spores and pollen, with length scales of microns and above. When the biologically active content of such particles is removed the resulting deflated spheres and ellipsoids can be used as empty vesicles, and reflated for the transport materials, such as dyes, magnets, and insulin. In between the nano- and macro-structures of particles there exists a strange regime that is neither; where the molecules appear as molecular grains in the macroworld, and have properties similar to those of granular matter. The molecules are of unusual shape, densely pack together, and behave like polymers. They form helical and plaited macrostructures without the need for local chirality or even molecular interactions. They exhibit anisotropic flow properties, with the possibility of exhibiting anisotropic entropic behaviour. Thus, within the interfaces separating the sciences, and the regime between the macro and nano-worlds, there is much to explore.

All living cells are coated with a sugar-rich layer which is called the glycocalyx. Clusters of sugars (glycans), on the periphery of the glycocalyx serve as ligands for sugar-recognition proteins, called lectins, on partner cells. Glycan-lectin recognition can be exquisitely specific. Many important biological processes depend on the ability of cells to appropriately communicate with each other via these sugar-lectin interactions and to respond accordingly. For example, lectins on the surfaces of viruses and bacteria are known to recognise sugars on target cells and attach to them as the first step of infection. Conversely the adaptive immune system is triggered when sugars on the surfaces of pathogens bind to lectins expressed by cells of the host immune system. Although these examples of glycan-lectin recognition are now relatively well understood, many biological processes that are likely to be similarly controlled by glycan-lectin interactions remain enigmatic. For example, how do immune cells in the gut distinguish between beneficial and harmful microbes, how do cancer cells evade the immune system, and how does a developing foetus escape rejection by the mother despite expressing "foreign" antigens? This talk will provide insights into the roles of glycans and lectins as “smart” molecules in biological recognition.

In a 2016 report, Goldman Sachs said: “The rapid adaptation of LEDs in lighting marks one of the fastest technology shifts in human history.” In the near future LED lighting will move from being passive to active: to “smart lighting”. There is increasing evidence that sunlight (if not excessive!) is good for our health. Next generation smart LED lighting will mimic sunlight indoors and reproduce the changing spectrum of sunlight from dawn to dusk. Next generation smart lighting will be used for communications, called LiFi, which will mimic WiFi but have certain key advantages. Next generation smart lighting will be central to the Internet of Things (IoT) and to water purification. Recent research on optimising the structure of GaN LEDs using machine learning has been used to predict laboratory earthquakes one week in advance by analyzing the acoustic signals emitted, and this is looking promising for the prediction of real earthquakes. At present, the acoustic signals only reliably give ten seconds warning of an earthquake.