Early diagnosis is crucial for the treatment and cure of a range of pathologies including cancers. The challenge diagnosis is to quantify the level of biomarkers at very low concentrations. In the diagnostic devices focus area of the ACN, researchers are developing a range of biosensors that are capable of detecting ultra-low concentrations of important cancer biomarkers. These biomarkers are all present in whole blood and are hence consistent with the idea of the liquid biopsy.

The basis of these technologies is the development of nanomaterials that can both preconcentrate and detect the biomarker of interest combined with a well-defined surface chemistry to ensure the sensor only detects the desired biomarker.

Projects include detecting microRNA in whole blood at attomolar levels, detecting low levels of protein biomarkers such as prostate-specific antigen and detecting heterogeneity in rare cancer cells. The technologies can be applied for both early detection and treatment efficacy. 

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Design of Macromolecular Contrast Agents for Magnetic Resonance Imaging

Magnetic resonance imaging (MRI) has emerged as one of the most powerful and widely used technique for noninvasive clinical diagnosis owing to its high degree of soft tissue contrast, spatial resolution, and depth of penetration. MRI contrast is determined by the relaxation times (T1, spin–lattice relaxation and T2, spin–spin relaxation) of in vivo water protons. According to the density and nature of the biological tissue, different contrasts can be observed.

To increase the contrast and the signal-to-noise ratio, contrast agents are usually administered to patients.These contrast agents can change the water relation in their surrounding by shortening T1 or increasing T2, resulting in hyperintense signals. The contrast agents are generally based on either iron oxide nanoparticles (providing negative contrast in T2-weighted images) or complexes of lanthanide metals (mostly containing gadolinium ions, providing positive contrast in T1-weighted images).

The Australian Centre of Nanomedicine designs the next generation of contrast agents by using nanotechnology. To achieve this aim, new functionalized iron oxide nanoparticles coated with biocompatible polymers are investigated. In contrast to conventional contrast agents, these nanoparticle contrast agents can be easily functionalized with therapeutic molecules, which can facilitate the accumulation of these agents in a specific tissue. By using this approach, a lower dose on contrast agents can be used.  

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