Navigation Links
Researchers uncover secrets of a mollusk's unique bioceramic armor

CAMBRIDGE, Mass-- The shells of a sea creature, the mollusk Placuna placenta, are not only exceptionally tough, but also clear enough to read through. Now, researchers at MIT have analyzed these shells to determine exactly why they are so resistant to penetration and damage even though they are 99 percent calcite, a weak, brittle mineral.

The shells' unique properties emerge from a specialized nanostructure that allows optical clarity, as well as efficient energy dissipation and the ability to localize deformation, the researchers found. The results are published this week in the journal Nature Materials, in a paper co-authored by MIT graduate student Ling Li and professor Christine Ortiz.

Ortiz, the Morris Cohen Professor of Materials Science and Engineering (and MIT's dean for graduate education), has long analyzed the complex structures and properties of biological materials as possible models for new, even better synthetic analogs.

Engineered ceramic-based armor, while designed to resist penetration, often lacks the ability to withstand multiple blows, due to large-scale deformation and fracture that can compromise its structural integrity, Ortiz says. In transparent armor systems, such deformation can also obscure visibility.

Creatures that have evolved natural exoskeletons many of them ceramic-based have developed ingenious designs that can withstand multiple penetrating attacks from predators. The shells of a few species, such as Placuna placenta, are also optically clear.

To test exactly how the shells which combine calcite with about 1 percent organic material respond to penetration, the researchers subjected samples to indentation tests, using a sharp diamond tip in an experimental setup that could measure loads precisely. They then used high-resolution analysis methods, such as electron microscopy and diffraction, to examine the resulting damage.

The material initially isolates damage through an atomic-level process called "twinning" within the individual ceramic building blocks: Part of the crystal shifts its position in a predictable way, leaving two regions with the same orientation as before, but with one portion shifted relative to the other. This twinning process occurs all around the stressed region, helping to form a kind of boundary that keeps the damage from spreading outward.

The MIT researchers found that twinning then activates "a series of additional energy-dissipation mechanisms which preserve the mechanical and optical integrity of the surrounding material," Li says. This produces a material that is 10 times more efficient in dissipating energy than the pure mineral, Li adds.

The properties of this natural armor make it a promising template for the development of bio-inspired synthetic materials for both commercial and military applications such as eye and face protection for soldiers, windows and windshields, and blast shields, Ortiz says.


Contact: Andrew Carleen
Massachusetts Institute of Technology

Related biology news :

1. Scripps Florida scientists offer best practices nutrition measurement for researchers
2. Researchers identify new protein markers that may improve understanding of heart disease
3. Two researchers known for identifying and treating bubble boy disease honored by March of Dimes
4. Researchers at IRB discover a key regulator of colon cancer
5. Researchers reveal the dynamics behind Arctic ecosystems
6. IRCM researchers uncover a new function for an important player in the immune response
7. UGA researchers explore function of cancer-causing gene
8. Researchers present comprehensive roadmap of blood cells
9. UT Southwestern ob/gyn researchers studying genetic factors in premature births
10. Researchers issue state-of-the-state on genetic-based testing & treatment for breast cancer
11. Miscarriage clues identified in new DNA test according to researchers at Montefiore and Einstein
Post Your Comments:
(Date:11/17/2015)... Paris from 17 th until 19 th ... from 17 th until 19 th November 2015.   ... the first combined scanner in the world which scans both ... two different scanners were required: one for passports and one ... same surface. This innovation is an ideal solution for electronic ...
(Date:11/16/2015)... 2015  Synaptics Inc. (NASDAQ: SYNA ), ... announced expansion of its TDDI product portfolio with ... and display driver integration (TDDI) solutions designed to ... TDDI products add to the previously-announced TD4300 ... resolution), and TD4322 (FHD resolution) solutions. All four ...
(Date:11/11/2015)... 11, 2015   MedNet Solutions , an innovative SaaS-based ... research, is pleased to announce that it will be a ... event, to be held November 17-19 in ... live demonstrations of iMedNet , MedNet,s easy-to-use, ... iMedNet has been able to deliver time and cost ...
Breaking Biology News(10 mins):
(Date:11/30/2015)... ... November 30, 2015 , ... ... tighter software integration with MarkLogic, the Enterprise NoSQL database platform provider, creating ... drive change. , Smartlogic’s Content Intelligence capabilities provide a robust set of ...
(Date:11/27/2015)... ... November 27, 2015 , ... Pittcon is pleased to announce ... offered in symposia, oral sessions, workshops, awards, and posters. The core of ... applications such as, but not limited to, biotechnology, biomedical, drug discovery, environmental, food ...
(Date:11/25/2015)... --> ... 2020 report analyzes that automating biobanking workflow will ... long-term samples, minimizing manual errors, improving the workflow ... errors such as mislabeling or inaccurate sample barcoding ... a vital role in blood fractionation, DNA extraction, ...
(Date:11/25/2015)... HOLLISTON, Mass. , Nov. 25, 2015 ... HART ), a biotechnology company developing bioengineered organ implants ... McGorry will present at the LD Micro "Main ... 2:30 p.m. PT. The presentation will be webcast live ... Management will also be available at the conference for ...
Breaking Biology Technology: