Tag Archives: Advanced Materials

aerogel

Turning jeans into joints: artificial cartilage from denim aerogel

This aerogel, which is synthesised from recycled denim, shares the material properties of joint cartilage. Image credit: Deakin University.

The team, which includes Deakin scientist Dr Nolene Byrne and PhD candidate Beini Zeng, have been pioneering advanced textile recycling methods in a joint project with Deakin’s Institute for Frontier Materials (IFM) and the School of Engineering.

One of their developments has been the use of recycled textiles to form aerogels.  Aerogels are a class of low density materials with a range of applications, which include water filtration and separators in advanced battery technologies.

Denim is an excellent candidate for forming aerogels because the cotton it is woven from is composed of a natural polymer, cellulose. “Cellulose is a versatile renewable material, so we can use liquid solvents on waste denim to allow it to be dissolved and regenerated into an aerogel,” explains Dr Byrne. The process is known as sol gel synthesis.

Aerogels have highly porous structures and extremely low densities. Dr Byrne describes the synthesis of the artificial cartilage aerogel as an unexpected discovery. “It has a unique porous structure and nanoscopic tunnels running through the sample. That’s exactly what cartilage looks like,” she said.

This surprising finding is particularly exciting because of the challenges involved with trying to control the properties of artificial cartilage in tissue engineering. “You can’t 3D print that material,” says Dr Byrne. “Now we can shape and tune the aerogel to manipulate the size and distribution of the tunnels to make the ideal shape.” The pores of the aerogel can be manipulated based on the drying technique – for example, supercritical CO2 drying is used to obtain an aerogel in the form of nanospheres.

The aerogels are now being tested to optimise their mechanical properties. “We are now entering pilot-scale trials and look to be at commercial scale within 3 to 5 years with industry support.”

This unique method of recycling denim will also help contribute to minimising textile waste, says Dr Byrne. “Textile waste is a global challenge with significant environmental implications, and we’ve been working for more than four years to address this problem with a viable textile recycling solution,” she said.

Textile recycling involves the use of chemicals, which can be both expensive and environmentally unfriendly. “We use environmentally-friendly chemicals, and by upcycling our approach to create a more advanced material we can address the limitations affecting other less cost-effective methods,” says Dr Byrne.

For more information, visit the Deakin Institute for Frontier Materials and the ARC Research Hub for Future Fibres.

– Larissa Fedunik

Researchers ride new sound wave to health discovery

Researchers ride new sound wave to health discovery

Feature image: RMIT researcher Dr Amgad Rezk

Acoustics experts at RMIT University have created a new class of sound wave – the first in more than half a century – in a breakthrough they hope could lead to a revolution in stem cell therapy.

The RMIT team combined two different types of acoustic sound waves called bulk waves and surface waves to create a new hybrid: “surface reflected bulk waves”.

The first new class of sound wave discovered in decades, the powerful waves are gentle enough to use in biomedical devices to manipulate highly fragile stem cells without causing damage or affecting their integrity, opening new possibilities in stem cell treatment.

Dr Amgad Rezk, from RMIT’s Micro/Nano Research Laboratory, said the team was already using the discovery to dramatically improve the efficiency of an innovative new “nebuliser” that could deliver vaccines and other drugs directly to the lung.

“We have used the new sound waves to slash the time required for inhaling vaccines through the nebuliser device, from 30 minutes to as little as 30 seconds,” Rezk says.

“But our work also opens up the possibility of using stem cells more efficiently for treating lung disease, enabling us to nebulise stem cells straight into a specific site within the lung to repair damaged tissue.

“This is a real game changer for stem cell treatment in the lungs.”

The researchers are using the “surface reflected bulk waves” in a breakthrough device, dubbed HYDRA, which converts electricity passing through a piezoelectric chip into mechanical vibration, or sound waves, which in turn break liquid into a spray.

“It’s basically ‘yelling’ at the liquid so it vibrates, breaking it down into vapour,” Rezk says.

Bulk sound waves operate similar to a carpet being held at one end and shaken, resulting in the whole substrate vibrating as one entity. Surface sound waves on the other hand operate more like ocean waves rolling above a swimmer’s head.

“The combination of surface and bulk wave means they work in harmony and produce a much more powerful wave,” says Rezk, who co-authored the study with PhD researcher James Tan.

“As a result, instead of administering or nebulising medicine at around 0.2 ml per minute, we did up to 5 ml per minute. That’s a huge difference.”

The breakthrough HYDRA device is improving the effectiveness of a revolutionary new type of nebuliser developed at RMIT called Respite. Cheap, lightweight and portable, the advanced Respitenebuliser can deliver everything from precise drug doses to patients with asthma and cystic fibrosis, to insulin for diabetes patients, and needle-free vaccinations to infants.

The HYDRA research has been published in the scientific journal Advanced Materials.

This article was first shared by RMIT University on 8 January 2016. Read the original article here.