Health & MedicineNanogold

Module Outcomes• Understand the importance of developing a

rapid diagnostic test for meningitis• Understand how nanotechnology can

improve the sensitivity of medical diagnostics

• Be familiar with the characteristics of nanoparticulate gold

• Identify recent developments in nanotechnology and how they may benefit human health.

What If?

Image: bbaunach@flickr

What if you could save a baby’s life with a rapid test for meningococcal disease?

What If?

Image: Benutzer:Lange123@wikipedia

What if you could selectively kill cancer cells and not surrounding healthy tissue?

Lung cancer

What If?

Image: © Dorling Kindersley

What if you could create tiny robots to scan your body for defects?

Activity 1The following is a headline from ABC news online, August 13 2008:‘A 14 year-old boy has died from a suspected case of meningococcal disease on the New South Wales central coast.’Perform the Meningitis Activity to learn more about this fatal disease.

How Do Bacteria Cause Disease?

Image: © Dorling Kindersley

• Produce a toxin

• Interfere with normal body processes

• Damage cells.

Meningococcal Meningitis

Image: © Dorling Kindersley

• The bacteria grow in the cells lining the nose and throat- spread by contact eg sneezing, kissing, sharing drinks

• The bacteria produce a toxin which causes fever, damage to blood vessels, tissue damage and blood clots

• It is fatal in about 10% of cases but 10-15% of people who survive the disease have ongoing health problems- eg deafness, loss of limbs, paralysis, brain damage

• Early diagnosis and treatment is critical to improve outcomes.

Two Types Of Meningococcal Disease

• Meningitis- bacteria attack the meninges (lining around the brain) - early symptom is a stiff, sore neck- meninges and brain swell, putting pressure on nerves- survivors often left deaf or with brain damage

• Sepsis- infection occurs throughout the bloodstream- affects the entire body- bacterial toxins rupture blood vessels and can rapidly shut down vital organs- survivors often left with permanent injuries and/or require amputations.

How Does Infection Start?

Image: © NOVA

• Meningococcal bacteria commonly live in the human throat without causing harm

• Sometimes they break through the throat's lining and enter the bloodstream

• Damage to the throat from influenza and other infections could be a predisposing factor.

Meningococcus penetrates cells lining the throat

Meningococcal Toxin

Image: © NOVA

• Every meningococcal bacterium is surrounded by a slimy outer coat that contains a poisonous chemical called an endotoxin

• While many bacteria produce endotoxin, the levels produced by meningococcal bacteria are 100 - 1000 times greater than normal.

Bubbles of endotoxin released from meningococcus

Tissue Damage

Image: © NOVA

Ruptured blood vessel leaks contents into surrounding tissue

• As the bacteria multiply and move through the bloodstream, they shed bubbles that contain concentrated amounts of toxin. These bubbles also act as decoys, confusing the body's immune system

• The endotoxin targets the heart, affecting its ability to pump and also causes blood vessels throughout the body to leak. As every vessel starts to haemorrhage, major organs like the lungs and kidneys are damaged and eventually destroyed

• Two things can stop this runaway infection before the patient dies: antibiotics like penicillin, and the patient's own immune system.

Not All Bacteria Is Bad

Image: Yakult.Honsah@wikipedia

• Very few bacteria are harmful, most bacteria have the following functions: - Food production- Normally live on our bodies and stop pathogenic bacteria from growing- Help with digestion (hence dietary supplements)- Can be genetically altered to make the products we need in the laboratorye.g. vaccines, drugs.

Experiment 1 Observation Of Bacteria

Perform the Observation of Bacteria experiment as instructed by your teacher.

How Can We Diagnose Meningitis?• Current tests detect bacterial proteins in blood/other

fluid - can only detect in the range of micro)mol (10-

6) to pico mol (10-12) of protein concentration• If we develop new tests using gold nanoparticles

combined with DNA amplification we could detect molecule concentrations in the atto (10-18) mol range i.e. one million times more sensitive than current tests

• This would allow earlier detection and therefore faster medical interventions.

What Are Gold Nanoparticles?

Image: Northwestern University

• Gold nanoparticles (‘nanogold’) occur as clusters of gold atoms up to 100nm in diameter.

• Nanogold has unusual visible properties because the particles are small enough to scatter visible light- in contrast, mass gold reflects light

• Gold nanoparticles appear deep red to black in solution- colour depends on size of nanoparticles

• The distance between particles also affects colour- surface plasmon resonance is the term used by nanotechnologists to describe this effect. 5nm gold clusters

Gold nanoparticleGold nanoparticle

Experiment 2 Making Gold Nanoparticles

Perform or watch a demonstration of the Making Gold Nanoparticles Experiment to see the differing chromic properties of nanoparticulate gold for yourself.

Animation• View the Nanoparticles Diagnostics

Animation to better understand how gold nanoparticles are used to detect bacterial meningitis

• Complete a flow chart outlining the key steps in the nanoparticle diagnostic test.

Activity 2• Use the Nick’s Test PowerPoint

presentation provided by your teacher to model the use of a nanoparticle diagnostic test in real-life

• Answer the questions on the last slide.

Rapid DiagnosisSo nanogold can be used to rapidly diagnose meningitis…

…what else can nanogold offer to the world of medicine?

What If?

Image: © Dorling Kindersley

What if you could treat cancer without surgery?

• Imagine if you suffered from inoperable cancer.

• Imagine if your tumour grew in an important part of the brain. Surgery could save your life but you would end up permanently and severely disabled.

• Now, imagine if there was an alternative…

Nanogold: ‘Nanobullets’ To Treat Cancer

Image: iurifernandes@flickr

• Also called 'thermal scalpels‘ or ‘nano bullets’

• Particularly useful for small cancers that are embedded in vital tissues such as the brain

• The nanoshells are silica coated with gold nanoparticles that binds them to cancer cells, and are then injected into tumours

• Light from a near-infrared laser, which is harmless to healthy tissue, is absorbed by the nanoshells. The nanoshells heat up, destroying the tumour cells.

Nanogold: ‘Drug Smugglers’ To Treat Cancer

Image: Courtesy E. Zubarev, Rice University

• Gold Nanoparticles coated with bristles of an anticancer drug, Taxol®

• Travel inside cancer cells and bind to internal structures

• Sabotages cell machinery preventing cell division.

Perform the Gold Nanobullets Activity and the Golden Cancer Treatment Experiment to better understand the benefits of using nanogold to treat cancer.

Activity 3 & Experiment 3

But Wait!Nanogold can do more!

What If?

Image: ©Ambri

What if you could detect bacteria with a rapid, on-the-spot test?

• Australian scientists at Ambri Ltd (Sydney) have used nanotechnology to develop a rapid, single-use diagnostic test to detect bacteria in samples-could test biological fluids, food, water.

What If?What if you could detect disease at home with a ‘lab on a chip’?

• Nanoparticles are bound to antibodies that recognise a disease marker protein – a protein found only in a disease state, or at higher levels in a disease state

• When the protein is present in a sample, extraction of the magnetic particles also pulls out the gold nanoparticles because the two are bound together

• The DNA on the gold nanoparticle can be copied many times, so very small amounts of the original protein can be detected

• Potentially, nanoparticles with different

antibody and DNA fragment combinations could be used to search for multiple disease marker proteins at the one time (hence the 'biobarcode').

View the BioBarcode Animation

What If?What if you could rapidly sequence DNA on a space mission?NASA is working on a ‘Nanopore Sensor’ to rapidly sequence DNA- detect DNA of pathogenic bacteria or viruses in astronauts- sequence DNA of new life forms.

Image: mujitra@flickr

What If?What if you could improve X-rays to view organs in great detail?

Image: © Nanoprobes

X-ray of live mouse kidneys using:

Iodine as contrast agent Gold nanoparticles as contrast agent

kidney

ureter

spine

Advantages Of Nano-Imaging

Image: © Nanoprobes

ureter

• Provide better contrast than conventional agents

• Biocompatible and non-toxic- useful for sensitive organs like the kidney- highly valuable for people who are allergic to dyes. Gold nanoparticles highlight the

cancer in mouse leg (arrow) compared to the other healthy leg.

Nano-Imaging In Australia

ureter

Nanotechnology Victoria and RMIT Medical Radiations have a collaboration investigating the use of nanogold for combined X-Ray imaging and radiotherapy, with a focus on cancer detection and treatment. 

Dr Jeanette Pritchard, Manager, Imaging Delivery & Sensing, Nanotechnology

Victoria Ltd

Animation

ureter

View the Nano-imaging Animation.

Now Let’s Get Really Imaginative….

ureter

What If?

ureter

• A ‘nanobot’ is a robot constructed from nanoscale components

• Nanobots could one day be injected into the body to treat diseases by delivering drugs or to perform surgery

• Nanobots could also perform a surveillance function where they check that the body is healthy and detect diseases very early.

Nanobot To Clean Arteries

Image: © Dorling Kindersley

ureter

Nanobot Research In Australia

ureter

• Researchers led by Dr James Friend at the MicroNanoPhysics Research Laboratory at Monash University, Melbourne are developing robot-like components and motors at the micro- and nano-scales.Watch the Micro-motor Animation to learn more

Activity 4Perform the Nanobots and Design Your Own Nanobot activities to explore this concept further.

Quantum Problems

ureter

• Play Duckboy in Nanoland!www.sciencemuseum.org.uk/antenna/nano/nanoland/nanoworld.asp

• MURKY MANSION• STUCK WITH THE DUCK• STRANGE ATTRACTIONS• BROWNIAN BUMPERS• FUNHOUSE

• Answer the questions in the Design Your Own Nanobot

Activity which relate to this game.

Summary

ureter

• Meningococcal meningitis is a deadly bacterial disease for which rapid diagnosis can be critical to prevent death and permanent side effects

• Gold nanoparticles have been used by Australian scientists to develop a rapid and sensitive test for meningococcal meningitis

• Gold nanoparticles are the focus of many health tools currently in development- targeted at prevention, diagnosis and treatment.

Revision1. What is bacterial meningitis and how do

the bacteria cause the symptoms of the disease?

2. Why have scientists developed a rapid diagnostic test for meningococcal infection?

3. Describe one way that gold nanoparticles can be used to treat cancer.

4. Do you believe that nanobots will one day be a reality? What problems must nanobot designers overcome?