Strong and resilient synthetic tendons produced from hydrogels

Human tissues exhibit a remarkable range of properties. A human heart consists mostly of muscle that cyclically expands and contracts over a lifetime. Skin is soft and pliable while also being resilient and tough. And our tendons are highly elastic and strong and capable of repeatedly stretching thousands of times per day. While limited success has been achieved in producing man-made materials that can mimic some of the properties of natural tissues (for instance polymers used as synthetic skin for wound repair) scientists have failed to create artificial materials that can match all the outstanding features of tendons and many other natural tissues. An international team of researchers has transformed a standard hydrogel into an artificial tendon with properties that meet and even surpass those of natural tendons. This new material was examined via electron microscopy and x-ray scattering to reveal the microscopic structures responsible for its outstanding features. The x-ray measurements were gathered at the U.S. Department of Energy’s (DOE’s) Advanced Photon Source (APS). The researchers have shown that their new hydrogel-based material can be modified to mimic a variety of human tissues and could also potentially be adapted to non-biological roles. Their results were published in the journal Nature.

Read more on the APS website

Image: Fig. 1. SEM images (left) showing the deformation of the mesh-like nanofibril network during stretching and corresponding in situ SAXS patterns (right). Scale bars, 1 μm (SEM images); 0.025 Å−1 (SAXS images)

Credit: From M. Hua et al., Strong tough hydrogels via the synergy of freeze-casting and salting out,” Nature 590, 594 (25 February 2021). © 2021 Springer Nature Limited

Shedding light on the causes of arsenic contamination

An international team has used the Canadian Light Source at the University of Saskatchewan to uncover the elusive structure of two arsenic-containing compounds, information that can be used to prevent and predict arsenic contamination.

Arsenic occurs naturally in the environment, and it is present in ore deposits and the waste left behind by mining for gold, uranium, and other metals. The concern with arsenic-containing compounds, like yukonite and arseniosiderite, is that soil sources can find their way into waterways. Understanding how this happens on a structural level can help scientists — and industry — better understand how the two are formed and better protect the surrounding environment from potential arsenic contamination.

Discovered more than 100 years ago, yukonite and arseniosiderite, which are compounds of arsenic, calcium, iron and oxygen, have concealed their structure from scientists thanks to their low crystallinity. While it’s relatively easy to determine the structure of materials that have a high degree of crystallinity, because of the complexity in the way these minerals’ atoms are arranged, usual methods have come up short in painting a clear picture of their structure.

Using a special technique at the CLS called the pair distribution function (PDF), an international team of researchers from Canada, China, the USA, Italy, and Ireland was able to visualize for the first time how atoms are structured in samples of arseniosiderite, which is classified as semi-crystalline, and yukonite, which is considered a nano-crystalline mineral.

Read more on the CLS website

 Image: Specimen BM.62813 from the collections of the Natural History Museum, London 

Credit: © The Trustees of the Natural History Museum, London