The top three news stories of the week, as chosen by our resident students. This week’s top stories include the UK joining (yep, JOINING) a pan-European atomic microscopy project, graphene hair dye and genetic engineering hop essence could make beer more environmentally friendly.

By Lindsay McGregor

The UK joins the European XFEL

This week the UK became the 12th country to join the European XFEL (X-ray Free Electron Laser) which is situated in Hamburg, Germany, at the DESY Campus. The UK will contribute around 26 million Euro to the budget, which roughly works out as 2% of the total construction budget, and an annual contribution of 2% to the operation budget. This is a great move for British science and will continue Britain’s contribution to world leading X-ray science.

XFELs are like a cross between an X-ray microscope and a laser. The beam is comprised of electrons which are accelerated by alternating magnetic fields (caused by undulators) down a very long straight tunnel(3.4 km in the case of the European XFEL!). The electrons then form ‘microbunches’ which are short powerful pulses of energy and these electrons emit X-rays which can hit the sample hundreds or thousands of times a second. The X-rays that are emitted can have a wavelength of between 0.05 – 4.7 nm, meaning that the atomic scale can be probed in detail. XFEL provides a complementary technique to the research that is currently conducted at synchrotrons. The short laser pulses that can be achieved mean it is now possible to measure chemical reactions previous unseen by current methods.

This will have implications in many research areas such as biology, chemistry, physics and materials science.

https://www.xfel.eu/news_and_events/news/index_eng.html?openDirectAnchor=1435&two_columns=0

XFEL

50 Shades of Graphene

You’ll all be familiar with the wonder material that is graphene. Applications of ultra-light, ultra-thin, and ultra-strong graphene sheets seem limitless – and researchers have shown that it may have more uses in a slightly more abstract area: hair dyes.

Most hair dyes contain toxic compounds which can cause allergic reactions, or have even more severe consequences. They operate using a base (ie, ammonia) which cause the hair’s cuticle scales to expand and open, allowing aromatic amines or phenol-based colourants to diffuse into the hair. The final hair colour comes from the reaction of an oxidant (commonly hydrogen peroxide) with colourants to produce the final dye compounds. This method can cause permanent damage to the hair’s mechanical structure, so weaker bases or neutral pHs can be used instead. However this limits the effectivity of the hair dye itself, with the colour disappearing after a few washes.

Graphene oxide (GO) and reduced graphene oxide (r-GO) have been shown to serve as a suitable alternative. Easily applied by spraying and combing through to give hair a coating, graphene was shown to neither to weaken the hair, nor react with it, and leaves permanent colour that lasts over 30 washes. The researchers achieved a range of colours on blonde hair from medium brown to black by altering the proportion of graphene in the dye, giving it great versatility.

In addition, there are other properties that are of interest not found in conventional hair dyes. GO can conduct electricity so can disperse the charge which gives hair that annoying static feel. The dye can also affect temperature with heat dissipation qualities.

The researchers also hope that in the future this could have implications for sensing devices or energy storage materials.

Luo et al., Multifunctional Graphene Hair Dye, Chem (2018), https://doi.org/10.1016/j.chempr.2018.02.021

Graphene

Don’t worry, be hoppy

Good news for beer enthusiasts (PhD students) everywhere! That bitter taste we all know and love in our sweet nectar that comes from hops has been successfully genetically engineered for production, giving hope that our strict taste demands can be satisfied.

It is the flowers of the Humulus lupulus L. (hop plant) that contribute to the bitter flavor and fragrance of beer, and these are added during the wort boil in the brewing process. However, hops are a relatively energy and water intensive crop to produce (~100 billion L of water is required for annual irrigation of domestic hops), as well as having a variation in oil content affecting that taste we all enjoy so much. This makes it difficult for brewers to achieve a consistent taste in their batches of beer.

In a recent study1, to meet the increasing demand for hoppy beer, the flavor molecules that are associated with the hoppy taste in beer have been reproduced using a yeast strain. Controlled concentrations of both linalool and geraniol have been produced from brewer’s yeast by tuning the expression of key genes in the biosynthetic pathway. This allows for more consistency of the hop flavor than traditional methods. The taste was tried and tested – with it being reported than the engineered batch being more hoppy than the norm – fantastic news!

Usually genetic engineering of food is met with suspicion, however when the sustainability of the production of hops is taken into account, consumers are generally more understanding. The fact it also makes the production of one of our favourite drinks easier may also have a slight influence…

1         C. M. Denby, R. A. Li, V. T. Vu, Z. Costello, W. Lin, L. J. G. Chan, J. Williams, B. Donaldson, C. W. Bamforth, C. J. Petzold, H. V Scheller, H. G. Martin and J. D. Keasling, Nat. Commun., 2018, 9, 965.

Beer