New metals are moldable like plastic

New forms of metal can be turned into complex shapes easily and inexpensively like

plastic but retain the metals' strength and durability, U.S. researchers say.



Materials scientists as Yale University say some recently developed bulk metallic

glasses—alloys with randomly arranged atoms rather than ordinary metals' rigid,

orderly structure—can be blow molded like plastics into complex shapes that can't be

achieved using regular metal but without sacrificing any of the metals' characteristic

strength.



"These alloys look like ordinary metal but can be blow molded just as cheaply and as

easily as plastic," says Yale scientist Jan Schroers, whose team has created a number

of complex shapes including seamless metallic bottles, watch cases, miniature

resonators and biomedical implants, molded in less than a minute and twice as strong

as typical steel, a Yale release reported.



The alloys—made up of different metals, including zirconium, nickel, titanium and

copper—cost about the same as high-end steel, Schroers says, but can be processed as

cheaply as plastic.



The team blow molded the alloys at low temperatures and low pressures, where the bulk

metallic glass softens dramatically and flows as easily as plastic.



To carefully control and maintain the ideal temperature for blow molding, the team

shaped the alloys in a vacuum or in fluid.



"The trick is to avoid friction typically present in other forming techniques,"

Schroers says. "Blow molding completely eliminates friction, allowing us to create any

number of complicated shapes."



In addition, the researchers say, blow molding combines three separate steps in

traditional metal processing—shaping, joining and finishing—into one step, making

previously cumbersome, time- and energy-intensive processing quick and easy.



"This could enable a whole new paradigm for shaping metals," Schroers says.

A three-dimensional tissue model of the human gut has been developed that will aid in

the study of gastrointestinal diseases.

Until now, scientists have had to rely on two-dimensional cultures or live animal

models, but the novel 3D hydrogel scaffold method will offer more realistic

physiological conditions.

The researchers are particularly interested how gut bacteria can be used to induce

intestinal cells to behave like insulin-producing beta cells — a project that could

result in a simple oral treatment of type 1 diabetes.

’We knew the flat models weren’t accurate. Cells behave differently in different 3D

environments …this will enable us to better study drug absorptions and interactions

between epithelia and bacteria in the intestine,’ said project lead Prof John March of

the Department of Biological and Environmental Engineering at Cornell University in the

US.

The team created a hard plastic mould, then covered it with a softer, so-called

sacrificial mould, made from calcium alginate that could be dissolved, leaving a

collagen scaffold upon which live cells could be grown.

The researchers tested the model by seeding it with human colon cells. After being

cultured for three weeks, it was covered with fingerlike structures mimicking the

intestinal villi, the threadlike projections covering the surface of the mucous

membrane in the small intestine where fluids and nutrients are absorbed.

In this way, they avoided damaging the delicate shapes during separation of the moulds.

Scientists had previously managed to fabricate models as small as 1 or 2 microns, but

slightly larger sizes have eluded them.

The artificial gut March and team created is around 1mm high and 200 microns across,

and is easily visible under a scanning electron microscope. They are in the process of

acquiring patents for the technology, which could be used in other areas of biomedical

research, such as tissue engineering, pharmaceutical sciences and cell biology.