Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Material bones up

23.11.2001


Molecular scaffolding makes for good bone structure.
© SPL


Programmed molecules build themselves into a bone-mimic.

Scientists in the United States have made self-assembling synthetic bone1. Carefully designed building-blocks join up to mimic bone’s complex molecular-scale architecture, bringing better prosthetics a step closer.

Materials engineers are keen to emulate the strength and toughness of biominerals such as bone, tooth and shell. Mollusc shells, for example, a composite of the mineral calcium carbonate and sheets of organic tissue, are much tougher than an equivalent slab of the mineral alone. So, like a biomineral, the bone-mimic is a blend of hard mineral-like substances and soft organic ones.



Bone is a composite of the calcium-containing mineral hydroxyapatite and the protein collagen, the tough fibrous component of tendons and ligaments. Collagen fibres provide a scaffold on which hydroxyapatite crystals gather, conferring hardness.

Each collagen fibre is itself a delicately wrought cable of several string-like protein molecules. The fibres assemble spontaneously like pre-programmed girders. These hold the hydroxyapatite crystals together and govern the orientation of the stacked sheets of atoms in the crystals, enhancing the material’s strength.

Sam Stupp and colleagues of Northwestern University in Illinois have tailor-made small protein-like molecules called peptides. To each peptide they attached a tail that was insoluble in water, encouraging them to assemble into cylindrical columns with their tails pointing inwards, shielded from water.

These long, flexible columns formed a tangle of worm-like fibres. Stupp’s team fixed the fibres in place by bonding adjacent peptides on their surfaces. Similar bonds link collagen fibres into the connective tissue between cells.

The team also included molecular groups such as those that promote hydroxyapatite crystal formation in natural proteins. Finally, they added groups that make proteins stick to cells. These, they reasoned, would allow the self-assembling web to harbour living cells.

The researchers put this matrix in a solution of ions - primarily calcium and phosphate. Hydroxyapatite crystals grew on the scaffold; their atomic layers aligned with the fibres, just as they do on the collagen scaffold of bone.

References


  1. Hartgerink, J. D., Beniash, E. & Stupp, S. I. Self-assembly and mineralization of peptide-amphiphile nanofibers. Science, Published online 22 November (2001).


PHILIP BALL | © Nature News Service
Further information:
http://www.nature.com/nsu/011129/011129-3.html

More articles from Materials Sciences:

nachricht New biomaterial could replace plastic laminates, greatly reduce pollution
21.09.2017 | Penn State

nachricht Stopping problem ice -- by cracking it
21.09.2017 | Norwegian University of Science and Technology

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: The fastest light-driven current source

Controlling electronic current is essential to modern electronics, as data and signals are transferred by streams of electrons which are controlled at high speed. Demands on transmission speeds are also increasing as technology develops. Scientists from the Chair of Laser Physics and the Chair of Applied Physics at Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) have succeeded in switching on a current with a desired direction in graphene using a single laser pulse within a femtosecond ¬¬ – a femtosecond corresponds to the millionth part of a billionth of a second. This is more than a thousand times faster compared to the most efficient transistors today.

Graphene is up to the job

Im Focus: LaserTAB: More efficient and precise contacts thanks to human-robot collaboration

At the productronica trade fair in Munich this November, the Fraunhofer Institute for Laser Technology ILT will be presenting Laser-Based Tape-Automated Bonding, LaserTAB for short. The experts from Aachen will be demonstrating how new battery cells and power electronics can be micro-welded more efficiently and precisely than ever before thanks to new optics and robot support.

Fraunhofer ILT from Aachen relies on a clever combination of robotics and a laser scanner with new optics as well as process monitoring, which it has developed...

Im Focus: The pyrenoid is a carbon-fixing liquid droplet

Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.

A warming planet

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Creative use of noise brings bio-inspired electronic improvement

26.09.2017 | Physics and Astronomy

Filter may be a match for fracking water

26.09.2017 | Power and Electrical Engineering

Bacterial Nanosized Speargun Works Like a Power Drill

26.09.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>