Joanna Niedziółka, Institute of Physical Chemistry, PAS, Synthesis and surface modification of plasmonic nanostructures for (bio) molecular interaction

event date: 22 February 2018

The Centre of New Technologies invites to a seminar by

Joanna Niedziółka-Jönsson
Institute of Physical Chemistry, PAS

Synthesis and surface modification of plasmonic nanostructures for (bio)molecular interaction
22 February 2018 at 12 p.m.

Venue: Centre of New Technologies, Banacha 2C, Lecture Hall 0142 (Ground floor)
Host: Joanna Kargul

The key point in constructing biosensors based on metallic nanostructures concerns the proper modification of their surfaces with defined (bio)receptors. This important task involves not only the reproducible synthesis of homogenous nanostructures but also establishing reliable methods for functionalization of the nanostructures that would enable efficient exploitation of plasmonic interactions in such a hybrid system. In the presentation, we describe several architectures where successful control of biosensor activity of metallic nanostructures has been demonstrated.
In this work, we present several ways of modification of metallic nanostructures for applying them as optical biosensors. One example concerns immobilization of an antibody [1] or a biopolymer [2] for the bacteriophage T7 on gold nanospheres. The nanospheres were chosen to have the localised surface plasmon resonance in the visible range, while the T7 bacteriophage was used as a model system of mammalian viruses belonging to the family of adenoviruses. In the presence of the target virus, which forms an immunocomplex with the antibody, the nanospheres tend to agglomerate. The resulting shift of the plasmon absorption band can be easily detected by eye as the sample suspension changes its colour. The efficiency of this effect scales with the virus concentration. These relatively simple modifications of the metal nanoparticle surfaces resulted in fast and sensitive immunotests with detection limits in the range of 1010 pfu/ml [1] or 105 pfu/ml [2].
Metallic nanowires, due to their ability to efficiently transport excitations, are also very suitable nanostructures to construct biosensors. Moreover, the diameters of such nanowires, which are in the range of 100 nm, are small enough to exhibit plasmonic effects in the visible spectral range, while their lengths exceeding tens of micrometres make them visible with a standard optical microscope. We intend to discuss selected properties of silver nanowires synthesized using a wet-chemistry approach [3]. The surface of the nanowires is amenable to a large array of surface functionalisation techniques, for example using thiol reactions. We used the silver nanowires for dynamic detection of the bacteriophage T7 in solution and this approach results in lowering the detection limits to 103 pfu/ml. In the experiment focused on real-time attaching photosynthetic pigment-protein complexes to the nanowires, we demonstrate a significant impact of the substrate functionalization on the efficiency of the conjugation process.

[1]Lesniewski, A.; Łos, M., Jonsson-Niedziolka, M., Krajewska, A., Szot, K., Los, J. and Niedziolka-Jonsson, J., “Antibody modified gold
nanoparticles for fast and selective, colorimetric T7 bacteriophage detection”, Bioconjugate Chem., Vol. 25, 644-648, 2014.
[2]Kannan, P., Los, M., Los, J. and Niedziółka-Jönsson, J.,” T7 bacteriophage induced change of gold nanoparticle morphology;
Biopolymer capped gold nanoparticles as a versatile probe for sensitive plasmonic biosensor”, Analyst, Vol. 139, No. 14, 3563 – 3571,
[3]Szalkowski M., Sulowska K., Grzelak J., Niedziolka-Jonsson J., Rozniecka E., Kowalska D., Mackowski S., „Wide-field fluorescence
microscopy of real-time bioconjugate sensing”, Sensors, Vol. 18, 290, 2018.