New affinity biosensors as diagnostic tools for biomedical analysis

Giovanna Marrazza 

Dipartimento di Chimica Ugo Schiff, Università di Firenze, via della Lastruccia,3, Sesto Fiorentino (Firenze) 50019, Italy

Abstract

Over the last decade, great attention has been paid to the integration of newly developed nanomaterials such as nanowires, nanotubes and nanoparticles in biosensor systems. The reason can be traced to their technologically important combination of properties, such as high surface area, good electrical properties, chemical stability and ease of miniaturisation, which make them very promising for the realisation of nanoscale bio-electronic device.

Moreover, the field of molecular diagnostics has expanded rapidly. Applications range from the detection of mutations responsible for human inherited disorders, disease-causing and food-contaminating viruses and research into bacteria and forensics.  Detection of infectious species and genetic mutations at the molecular level opens up the possibility of performing reliable diagnosis even before any symptom of a disease appears. Additionally, the development of novel therapeutics based on the regulation of gene expression provides revolutionary new opportunities in the area of pharmaceutical science.

Focusing on the most recent activity of our research group, the aim of the present talk is to give a critical overview of novel micro or nanoscale biosensors for the detection of cancer biomarkers, consisting in tumour associated antigens or gene mutations. Existing methods for cancer screening are still invasive, complex and quite expensive, being based on tissue sampling and cell morphology examination. Bioaffinity tests are instead based on simple and rapid detection of a wide range of biomarkers such as DNA mutations, RNA small sequences (micro-RNA), proteins (enzymes and glycoproteins), hormones and other kind of molecules. Thus, the combination of nanomaterials with such bio-assays offer the possibility of tailoring optimal sensing devices able to facilitate disease diagnosis (molecular diagnostics) as well as therapies optimisation (theranostics).

We have employed nanotechnology to develop small, fast, low-cost, ultrasensitive and highly specific biosensors for next-generation gene chips, based on different miniaturisation pathways. Carbon nanotube as well as magnetic nanoparticle-modified electrodes have been designed and tested for the detection of micro-RNA and DNA mutations. Gold nanoparticles have been synthesised and functionalised with antibodies and affibodies specific for tumor markers sensing. Moreover, polymeric nanotube arrays have been constructed for chemical grafting with new mimetic bioreceptors for clinically relevant analytes monitoring.Different immobilisation chemistries have been investigated by introducing functional groups (e. g. –OH, -COOH, -NH2) suitable for each nanomaterial in order to assure high reactivity, orientation, accessibility and stability of the surface-confined receptors as well as for minimising non-specific adsorption events.

This talk will finally look into some recent advances of nanobiosensor by analyzing the trends, limitations, challenges and commercial devices in the field of clinical diagnostics.

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Presentation: Keynote lecture at SMCBS'2011 International Workshop, by Giovanna Marrazza
See On-line Journal of SMCBS'2011 International Workshop

Submitted: 2011-08-19 13:19
Revised:   2011-08-19 13:31
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