Microchannels with controlled width from 59 µm to 155 µm and depths ranging from 22 µm to 77 µm were fabricated on cyclic olefin polymer substrates. The experimental ablation rate was calculated based on the microchannel depth and the number of incident laser pulses, and was compared to that expected from theory with ablation rates ranging from 13 nm/pulse up to 55 nm/pulse observed. Combining the laser patterns and their modification with PLAL-nanoparticles resulted in functional and biocompatible substrate for biosensing applications. Our in-vitro cell viability studies using a model cell line (human skin keratinocyte, HaCaT) suggest that these nanoparticles immobilized on the surfaces functions as a biomimetic platform with the ability to interact with different biological entities (e.g. DNA, antibodies etc.). Additionally, to utilize laser generated gold nanoparticles for sensing applications, optical properties for Laser induced gold nanoparticles and commercially available nanoparticles were compared using Raman and Fluorescence spectroscopy using custom made ruthenium dye. Using these results, ultrasensitive detection of of C-reactive protein (cardiac biomarker detection) was carried out.
Finally, we developed an electrochemical sensor for HPV upon covalent functionalization of the electrode with an aptamer Sc5-c3, a RNA aptamer targeted against the HPV-16 L1 protein. Using differential pulse voltammetry (DPV), a linear relationship between the peak current of a redox couple such as Fe(CN)64-/3- and the concentration of HPV16 L1 proteins in the range of 0.3-2 ng mL-1 (5.3 pM-35.3 pM) could be reached with a detection limit of 0.3 ng mL-1 (5.3 pM). Cross-reactivity studies demonstrated high selectivity over potential interfering species such as HPV16 E6, facilitating application of the developed concept for the development of point of care devices.
The above-mentioned results were communicated through journal publications
- “Microchannel fabrication on cyclic olefin polymer substrate via 1064 nm Nd:YAG laser ablation" Applied Surface Science Volume 387, 2016, Pages 603–608
- “Nanoparticle functionalized laser patterned substrate: an innovative route towards low cost biomimetic platforms” RSC Advances 7 (13); 2017; pp 8060-69
- “Carbon nanoparticle functionalisation of laser textured polymer surfaces for chemical and biological speciation” Lasers in Engineering, 36 (1-3); 2017; pp 63-72
- “Pulsed laser deposition of plasmonic nanostructured gold on flexible transparent polymers at atmospheric pressure”. J Phys D Appl Phys.2017;50(24).
- “ Nucleic aptamer modified porous reduced graphene oxide/MoS2 based electrodes for viral detection: Application to human papillomavirus (HPV) Sensors and Actuators B: Chemical (Accepted, in print)
- “Taguchi method modelling of Nd:YAG laser ablation of microchannels on cyclic olefin polymer films” (revision submitted, under review)
- “Modelling and optimisation of single-step laser-based gold nanostructure deposition with tunable optical properties” C Hughes, R McCann, J Eguileor, K Bagga, R Groarke, F Regan, D Brabazon. Applied Physics Letters (under review)
- Laser generated ligand-free nanoparticles for ultrasensitive detection of cardiac biomarker detection. (in preparation)
- Electro-catalytic properties of laser generated gold nanoparticles on graphene sheet (in preparation)
Conference Proceedings Papers:
- Bagga K, McCann R, Brasi Q, Coussy J, Stalcup A, Vázquez M, Brabzon D. "Laser-assisted synthesis of ultrapure nanostructures for biological sensing applications", Proc. SPIE 9928, Nanobiosystems: Processing, Characterization, and Applications IX, 99280O.
- Nanoparticle Fabrication via Pulsed Laser Ablation in Liquid: A Step Towards Production Scale-up” B Freeland, R McCann, P.O’Neill, K Bagga, G Foley and D Brabazon AIP Conference Proceedings (In Press)
Conference participation
- “Innovative biological and chemical detection platform based on laser processing of nanomaterials” 2nd International Conference nanoFIS 2016 - Integrated Functional nano Systems. 27-29 June 2016 Graz, Austria.
- “Nanoparticle Fabrication via Pulsed Laser Ablation in Liquid: A Step Towards Production Scale-up” 20th International ESAFORM Conference, 26 – 28 Apr 2017, Dublin, Ireland.
- “Green” laser-based synthesis nanoparticles towards waste water treatment applications B Freeland, 7th International Colloids Conference, Barcelona, Spain, June 2017
- “Carbon nanoparticle functionalisation of laser textured polymer surfaces for chemical and biological speciation” 38th Matador Conference, Taipei, ROC.
- “Picosecond Nd:YAG laser ablation of cyclic olefin polymer substrates for sensing platform fabrication” ICASS 2015, 27 – 30 July, 2015, Shanghai, PRC.
- "McCann R, Delaney B, Bagga K, Stalcup A, Vázquez M, Costello J T, Brabazon D. “Single-step laser deposition of nanostructured gold thin films on flexible polymer substrates” Photonics Ireland 2017, Galway, Ireland
