High-throughput Synthesis of Non-spherical Plasmonic Nanoparticles (NPs) for Applications in Endotoxin Sensing (Nano-Syn-Sens)
Alternative title: Syntetese av høy gjennomstrømning av ikke-sfæriske plasmoniske nanopartikler (NP) for applikasjoner i endotoksinsensering (Nano-Syn-Sens)
Administrative corner:
As the project entered into its second year, the major focus has been on aligning the research activities of both Norwegian and Indian partners towards the preset project milestones. There seems to be continued funding challenges on the Indian side due to change in infrastructure and personnel responsible for administration of the project in the funding organization. Some of the research activities in this project have been greatly benefited through a research mobility funded by Global Erasmus Mobility Program project operational between the project co-ordinators on both sides during the period 2020 – 2023. Since the project had delayed startups on both sides due to corona and late release of funds on the Indian side, a new application will be sent for extending the final date of the project.
Technical corner:
Norwegian side: Q1-Q2 2022 focussed on completion of the review article with a focus on the use of binary surfactants in controlling the growth of anisotropic gold nanostructures. The manuscript was submitted to ACS journals and after receipt of review recommendations in Q3 2022, several aspects of the manuscript were revised. This manuscript has now been submitted to a new journal for review.
Our focus has been on understanding the role of tannic acid as a reducing agent in the seeded growth synthesis method. The research results are now being drafted into a manuscript which will be submitted in Q1 2023. We have also developed new protocols for calculating the yield of gold nanostructures using atomic emission spectroscopy. This method will be used extensively for characterization of the particles in the future. A large effort has been put on functionalization of the surfaces of the nanoparticles to anchor them to the optical fibre-based biosensors on the Indian side. These results have been summarized in the form of one master theses – Tailoring Magneto-Plasmonic Nanoparticles for Biosensing Applications and a master specialization project which will be submitted end of December 2022. In addition, the results have been presented at in national and international forum through posters and oral contributions. Several of the findings have been used for education both as components in TKP 4190 Fabrication and Application of Nanomaterials and TKP 4535 Crystallization and Particle Design Courses at NTNU, but also in invited lectures delivered digitally and physically for international universities.
Since the project aims to study batch and continuous processes, Q3-Q4 have focused on the transition into microfluidic systems. We have progressed on building the platform for the same through a visiting PhD exchange student under the Global Erasmus Mobility Program and the setup is expected to produce preliminary results in Q1 2023. In addition, the Indian principal investigator also came on a one month mobility on the same project, which facilitated structured discussions and project planning for the next period.
Since exchange and physical meetings could not be arranged in the first year of the project, the budget has been transferred for hiring a summer student that worked towards establishment of some of the protocols and provided support to the PhD student’s main research work. There has been a major role change in the microfluidics work which has been done by an additional resource provided through the Erasmus mobility.
Indian side: The PhD on the Indian side has been working on developing molecular dynamic simulations for studying adsorption of surfactants on gold seeds, that serve as the starting material for the seeded growth synthesis. The results from this work were published in a peer-reviewed international journal in Q4 2022. Studies are also in progress to understand structural and thermodynamical property calculations in regards to binding of binary surfactant mixtures to the surface of gold seeds. In this regard, we have chosen DDAB as the co-surfactant, since, our lab has previously published experimental results using this co-surfactant.
On the biosensor development side, we have published in Q1 2023 the first results from the study focusing on Ag@Au core-shell nanoparticles coated U-bent fiber optic probes. A high refractive index sensitivity was observed in this system and will form the basis for comparison with the system decorated with our anisotropic nanoparticles. Current work is focusing on testing different functionalized spherical gold nanoparticles to understand their anchoring on the surfaces of the optic probes.
This project aims to understand and control growth of anisotropic Au NPs in seeded-growth strategies using a complementary approach that combines experimental and multi-scale modelling techniques for both batch and continuous processes. The obtained Au NPs will then be functionalized for biosensing of endotoxins based on optical fibre technology. The project aims to improve health and promote new medical technology and also provide greater insight into the impacts of nanomaterials on human health and ecosystems.
The project team comprises experts in experimental as well as theoretical methods with special competences in NP fabrication, characterization, scale-up and mathematical modelling. State-of-the art nano research infrastructure at NTNU Nanolab will be used for fabrication and characterization while multi-scale modelling knowledge, approaches and facilities at IIT-M will be used for developing process models that capture the growth. The proposal aims to solve a pressing societal need of providing cheap, in-house and improved healthcare and medical facilities in biosensing which will be realized in the Biosensors Labortory at IIT-M. Although several reports exist documenting seeded growth, to our knowledge, there exists no comprehensive mathematical modelling in case of binary surfactant mixtures. Further, using microfluidic routes, high throughput of anisotropic Au NPs will be achieved. Functionalization of the Au NPs to chemisorb them on fibreoptic sensors will help realize ultrasensitive plasmonic sensors for endotoxin detection.
The project would therefore provide fundamental understanding of nucleation and growth of anisotropic Au NPs with an aim to fabricate in-house sensors, the technology behind which can be patented. It also aims to educate 3 PhDs within the research area over the project period, foster ongoing collaborative research between the partners and establish research ties for long-term co-operation.
