Wednesday, 20 November 2024 11:00am – 12:00pm

This seminar will be delivered in Lecture Theatre 4

Speaker: Scientia Professor J. Justin Gooding

Host: Dr Kaye Kang

Title: From artificial enzymes to ultrasensitive, or even single molecule biosensors that operate in complex biological fluids

Abstract: This presentation will cover recent advances in three major directions in sensing in complex biological fluids. Firstly, the concept of nanozymes, nanoparticles that serve as artificial enzymes by performing reactions that enzymes also perform. As attractive as this concept is, nanozymes have been challenged by poor selectivity in complex biological fluids. Herein, we will show how nanoparticles that are designed with similar three-dimensional geometry to enzymes, with active centres down nanoconfined substrate channels can be used to develop biosensors that can detect glucose in whole blood [1].

Next we turn our attention to the liquid biopsy and the monitoring of microRNA released from single 3D printed spheroids [2] to begin to understand what information from the liquid biopsy could mean in terms of drug treatments. To achieve this we require ultrasensitive sensors that allow us to detect tiny amounts of biomarkers released from the spheroids. For our proof of concept work we use gold coated magnetic nanoparticles (Au@MNPs) as dispersible electrodes which allow the development of ultrasensitive sensors for proteins and microRNA, even down to just a few thousand molecules [3].

Finally, the presentation pivots to single molecule sensors and how we can detect single molecules, and single molecule binding events, by viewing a biosensing surface in a wide field format and imaging individual molecules. We show how super-resolution fluorescence microscopes, specifically stochastic optical reconstruction microscopy (STORM) allows widefield imaging with single molecule resolution can be turned into a single molecule counting approach as well using electrochemistry; an approach we developed call electrochemical or EC-STORM. We have shown that electrochemistry can be used to do this fluorescence switching without photobleaching of molecules such that molecular counting seems possible [4].  The talk discusses how this is done before demonstrating the molecular counting approach.

References

[1] T.M. Benedetti, S.V. Somerville, J. Wordsworth, Y. Yamamoto, W. Schuhmann, R.D. Tilley, J.J. Gooding, An artificial enzyme: How nanoconfinement allows the selective electrochemical detection of glucose directly in whole blood, Adv. Funct. Mater. 34 2400322 (2024).

[2] R.H. Utama, L. Atapattu, A.P. O’Mahony, C.M. Fife, J. Baek, T. Allard, K.J. O’Mahony, J. Ribeiro, K. Gaus, M. Kavallaris*, J.J. Gooding*, A 3D Bioprinter Specifically Designed for the High-Throughput Production of Matrix-Embedded Multicellular Spheroids, iScience 23 101621 (2020).

[3] R. Tavallaie, J. McCarroll, M. Le Grand, N. Ariotti, W. Schuhmann, E. Bakker, R.D. Tilley, D.B. Hibbert, M. Kavallaris, J.J. Gooding*, DNA-programmed electrically reconfigurable network of gold-coated magnetic nanoparticles enables ultrasensitive microRNA detection in blood, Nature Nanotech. 13 1066-1071 (2018).

[4] Y. Yang, Y.Q. Ma, R.D. Tilley, K. Gaus, J.J. Gooding, Electrochemically controlled blinking of fluorophores for stochastic optical reconstruction microscopy (STORM) imaging, Nature Photon. 18 713-720 (2024).

Bio: Scientia Professor Justin Gooding is currently an National Health and Medical Research Council Investigator Awardee a Fellow of the Australian Academy of Science, the Australian Academy of Technology and Engineering and the Australian Academy of Health and Medical Sciences. He was previously an Australian Research Council Australian Laureate Fellow and will soon take up a position an Australian Industry Laureate Fellowship.. He is the inaugural editor-in-chief of the journal ACS Sensors. He is the former founding co-director of the Australian Centre for NanoMedicine and the co-director of the New South Wales Smart Sensing Network. He is the 2024 Australian Academy of Science David Craig Medallist.

He leads a research team of over 40 researchers interested in surface modification and nanotechnology for biosensors for medical applications, electrocatalysis and 3D cell printing. He has extensive collaborative experience with start-up companies and has been involved in the commercialisation of glucose biosensors, 3D bioprinters and in vivo sensing.