Breaking News
February 18, 2019 - Breast cancer screening age should be lowered to 35
February 18, 2019 - Brain synchronization depends on the language of communication
February 18, 2019 - Drug Company Payments Over Time May Influence Rx Practices
February 18, 2019 - Despite socioeconomic gains, black-white ‘health gap’ remains
February 18, 2019 - Researchers report progress in the treatment of aggressive brain tumors
February 18, 2019 - Scientists discover trigger that turns strep infections into devastating disease
February 18, 2019 - Scanning children’s teeth may predict future mental health issues
February 18, 2019 - Health Highlights: Feb. 14, 2019
February 18, 2019 - New knowledge could help predict and prevent depression
February 18, 2019 - More primary care physicians leads to longer life spans | News Center
February 18, 2019 - Patented IU discovery to treat ARDS has been optioned to Theratome Bio
February 18, 2019 - Male Y chromosomes not ‘genetic wastelands’
February 18, 2019 - Hormone therapy during gender transition may increase risk for cardiovascular events
February 18, 2019 - NICE renews accreditation for Advanced
February 18, 2019 - FDA Grants Orphan Drug Designation to Amplyx Pharmaceuticals for APX001 for Treatment of Cryptococcosis
February 18, 2019 - Molecule effective in killing tuberculosis bacteria
February 18, 2019 - Columbia researchers unravel why some glioblastomas respond to immunotherapy
February 18, 2019 - Men who are able to do ten push-ups are less likely to have a stroke
February 18, 2019 - Blood-brain barrier disruption could lead to age-related cognitive decline
February 18, 2019 - Combination of PARP inhibitor and immunotherapy results in tumor regression in SCLC mouse models
February 18, 2019 - Heavy smoking could lead to vision loss, study finds
February 18, 2019 - New diagnostic test for malaria uses spit, not blood
February 18, 2019 - New therapeutic molecules show promise in reversing memory loss related to depression, aging
February 18, 2019 - Darla Shine joins anti-vaccination campaigners
February 18, 2019 - New study outlines sex-specific issues in ischemic heart disease
February 18, 2019 - Drug combinations could become first-line treatment for metastatic kidney cancer
February 18, 2019 - Lifetime adversity, increased neural processing during trauma combine to intensify core PTSD symptoms
February 18, 2019 - HRQoL Scores Decrease With Treatment Line in Multiple Myeloma
February 18, 2019 - Convincing evidence that type 2 diabetes is a cause of erectile dysfunction
February 18, 2019 - Study offers implications of advanced age in evaluation, management of ischemic heart disease
February 18, 2019 - Children from homes with flame-retardant sofa have high SVOC concentration in their blood
February 18, 2019 - Art Institute of Chicago announces results of research on five terracotta sculptures
February 18, 2019 - New PET/CT tracer shows high detection rate for diagnosis of acute venous thromboembolism
February 18, 2019 - Smoking may blight immune response against melanoma and reduce survival
February 18, 2019 - How Inactivity and Junk Food Can Harm Your Brain
February 18, 2019 - Diabetes tops common conditions for frequent geriatric emergency patients
February 18, 2019 - Longer-lived sperm produces offspring with healthier lifespans
February 18, 2019 - New dental adhesive prevents tooth decay around orthodontic brackets
February 18, 2019 - New eHealth tool shows potential to improve quality of asthma care
February 18, 2019 - New Australian initiative helps emergency clinicians to improve patient care
February 17, 2019 - Apellis Pharmaceuticals’ APL-2 Receives Fast Track Designation from the FDA for the Treatment of Patients with Paroxysmal Nocturnal Hemoglobinuria
February 17, 2019 - Researchers identify faulty ‘brake’ that interferes with heart muscle’s ability to contract and relax
February 17, 2019 - Support from trusted adults can reduce risk of dying in suicidal teens, finds study
February 17, 2019 - Heart attack awareness improved since 2008
February 17, 2019 - Exercise gives a better brain boost to older men than women
February 17, 2019 - New research disproves previous assumptions of how looks influence personality
February 17, 2019 - Cannabis use as a teenager linked to depression later in life
February 17, 2019 - Sinks by Toilets in ICU Patient Rooms Harbor Harmful Bacteria
February 17, 2019 - Cancer cells’ plasticity makes them harder to stop
February 17, 2019 - Young cannabis users have increased risk of depression and suicidal behavior
February 17, 2019 - Tasmanian Devils Likely to Survive Cancer Scourge
February 17, 2019 - Neoadjuvant PD-1 blockade seems effective in glioblastoma
February 17, 2019 - Personal, social factors play role in enabling sustainable return to work after ill health
February 17, 2019 - Mouse studies show ‘inhibition’ theory of autism wrong
February 17, 2019 - Study shows how neuroactive steroids inhibit activity of pro-inflammatory proteins
February 17, 2019 - Use of liver grafts from older donors decreased despite better outcomes in recipients
February 17, 2019 - MUSC researchers discover new mechanism for a class of anti-cancer drugs
February 17, 2019 - HPV misconceptions are causing women to miss smear tests
February 17, 2019 - Sanofi and Regeneron Offer Praluent (alirocumab) at a New Reduced U.S. List Price
February 17, 2019 - Researchers say auditory testing can identify children for autism screening
February 17, 2019 - New method analyzes how single biological cells react to stressful situations
February 17, 2019 - WVU gynecologic oncologist investigates novel treatment for cervical and vaginal cancers
February 17, 2019 - ADHD diagnoses poorly documented
February 17, 2019 - Majority of gender minority youth do not identify with traditional sexual identity labels
February 17, 2019 - AbbVie, Teneobio enter into strategic transaction to develop potential treatment for multiple myeloma
February 17, 2019 - Lower Birth Weight May Up Risk for Psychiatric Disorders
February 17, 2019 - Scientists identify reversible molecular defect underlying rheumatoid arthritis
February 17, 2019 - Moffitt researchers shed light on how CAR T cells function mechanistically
February 16, 2019 - Female Anatomy May Play Big Role in Sperm’s Success
February 16, 2019 - BMI may mediate inverse link between fiber intake, knee OA
February 16, 2019 - Movement impairments in autism can be reversed through behavioral training
February 16, 2019 - Studies address racial disparities in postpartum period and cardiovascular health
February 16, 2019 - Scientists implicate hidden genes in the severity of autism symptoms
February 16, 2019 - Decreased deep sleep linked to early signs of Alzheimer’s disease
February 16, 2019 - Neuroscientists show how the brain responds to texture
February 16, 2019 - Gilead Announces Topline Data From Phase 3 STELLAR-4 Study of Selonsertib in Compensated Cirrhosis (F4) Due to Nonalcoholic Steatohepatitis (NASH)
February 16, 2019 - What Can I Do About Sweating? (for Teens)
February 16, 2019 - Companies navigate dementia conversations with older workers
February 16, 2019 - Newly developed stem cell technologies show promise for treating PD patients
February 16, 2019 - Collaborative material research could advance self-assembling nanomaterials
Investigating Enamel Nanostructure with Nanoindentation

Investigating Enamel Nanostructure with Nanoindentation

image_pdfDownload PDFimage_print

An interview with Dr. S Amini, conducted by Jake Wilkinson, MSc

Why are you interested in biomaterials?

As a teenager, I was amazed by nature and wondered why people lost their teeth permanently, while sharks regenerated their teeth regularly? These questions were always on my mind.

© theowl84/Shutterstock.com

My primary interest was solid mechanics. During my master’s program, I got familiar with biomaterials, and started a project with the School of Dentistry on tooth restorative materials. The interest in biological materials further developed during my Ph.D. program in Biological and Biomimetic Materials Laboratory (BBML) at Nanyang Technological University, Singapore.

My project was mainly focused on biological hard tissues. Lately, I moved to the Max Planck Institute of Colloids and Interfaces, Department of Biomaterials, where I have the chance to closely collaborate with our different research groups and explore different biological models. Currently, I am working on structural properties and mechanical responses of damage-resistance biological models, such as shark teeth enameloid and human teeth enamel.

How do synthetic composites compare to the properties of teeth?

Minerals and proteins, the building blocks of the natural enamel, entangled in complex shapes to display the properties that go far greater than their individual properties. These hierarchical structures, which are composed of available and simple building blocks, are far beyond anything that we can produce synthetically. In addition, we are not able to mimic the gradients in synthetic materials that we can see in biological materials, such as the human tooth. These gradients have a crucial role in mechanical response and performance of the biological models.

We can now artificially use ceramic or polymer composites to repair our teeth, but we never regain the original properties since we induce artificial interfaces and replace the graded structure of the tooth with a homogenous material with mismatched properties. Nature has adopted complex design strategies to achieve high-performance biological composites that overcome harsh external stimuli, while hindering stress-mismatch failure occurring during cyclic loading.

How have you been using nanoindentation to further your understanding of biomaterials?

Mechanical characterization of materials dates back a few hundred years. The diverse studies resulted in a comprehensive data base for mechanical response of materials. However, due to technological limitations, engineers were not able to characterize the mechanical response of the microstructures to differentiate the behaviour of the building blocks, or the role of their spatial arrangements.

Thanks to recent advances in mechanical characterization techniques, such as atomic force microscopy and nanoindentation, we are now able to characterize the microstructural features of the materials. These advances allow us to see the role of micro- and nanostructures on the mechanical response of the overall structures. For example, we can understand how presence of minerals and their arrangement can affect the hardness or toughness of the samples.

What imaging techniques do you use alongside nanoindentation as part of your research?

I have used different imaging techniques, such as optical and electron microscopy, micro CT imaging, and Raman spectroscopic imaging, alongside my nanoindentation studies. Combining these techniques, we are able to correlate the structural and mechanical properties of the samples.

How does performing a nanoindentation experiment on biological material compare to conventional nanoindentation experiments?

There are lots of studies surrounding homogenous, inorganic or polymeric materials. Therefore, most of the testing methodologies are developed for these materials.

Conversely, organic phases are sensitive to humidity and temperature, and they can simply denature if not stored and prepared properly. As a result, specific protocols are needed to make sure that the samples keep their native characteristics.

Why is the use of an environmental chamber important for your research?

We frequently use humidity chambers so that the extracted mechanical properties are not affected by dehydration. The effect of dehydration depends on degree of mineralization of the samples. For example, if it’s a highly mineralized sample, dehydration does not significantly affect the mechanical properties. However, for soft samples that are highly organic, like skin and muscle, then environmental control (mainly humidity) is necessary. Tissues need to be tested at their functional environment; otherwise, they won’t have the same mechanical response.

Where do you expect our understanding of biomaterials to take us?

Our understanding of biomaterials continues to develop. The systems we can use to measure them are becoming increasingly sophisticated, empowering us to discover more and more about their structure and behaviour. My field is based on the characterisation of these materials not producing them, although the breakthroughs we make feed directly to the material engineers who use this information to create increasingly powerful materials.

New engineering techniques are bringing us closer to creating biomimetic materials, which will be able to match those we see in the natural world. For example, 3D printing will allow us to emulate the complex 3D or interwoven structure seen in biological models that results in its amazing properties. We will be able to accurately replicate the patterns we see in biological materials and create engineering materials that accurately mimic them. However, we are still limited by size and materials.

What value do you see in expert-led conferences such as Nanobrüken?

From my personal experience, even with the access through the internet and journals, scientific groups with different backgrounds all around the world are not connected in the way they should be. Having these interdisciplinary seminars and discussions, scientists can come up with new ideas and innovative solutions for their own research. Furthermore, you get some cases of a team working to design or develop a test method for their research; however, a similar method that has already been applied for years in a different field can be customized for your own research.

Conferences focusing on techniques instead of research area, like Nanobrüken, are helpful, because no matter what your background, you can attend and get new ideas in other fields. It facilitates the sharing of ideas and helps us all perform our research more effectively.

About Dr. Shahrouz Amini

Dr Amini is a post-doctoral researcher at the Max Planck Institute of Colloids and Interface, Department of Biomaterials (Supervisor: Prof. Peter Fratzl). With his research background on the mechanical characterization and properties of biological materials, Dr Amini is conducting studies on damage tolerant biological models such as tooth enamel.

Shahrouz received his PhD degree from Nanyang Technological University, Department of Materials Science and Engineering (Advisor: Prof. Ali Miserez). In 2016, he was awarded a “Research Excellence Award” for his PhD work on mantis shrimp dactyl club and its toughening strategies.

Tagged with:

About author

Related Articles