Campanile, Raffaele (2022) Gold decorated magnetic nanoparticles for biosensing. [Tesi di dottorato]

Preview

Text Campanile_Raffaele_34.pdf Download (5MB) | Preview

Collection description

The aim of the work in this thesis was to propose novel effective protocols for gold coating of commercial MNPs to improve the applicability of biosensors in environmental control, food safety and clinical analysis. Three different types of gold decorated magnetic nanoparticles were designed and tested in combination with as many types of biosensors. The introduction of MNPs@Au was aimed at improving the performance of already widespread biosensing setups, narrowing the gap in terms of sensitivity and applicability with gold standard techniques. This thesis work has been organized to provide the reader with the basic theoretical and experimental notions before delving into the innovative content. To this end, Chapter 1 briefly introduces biosensors focusing on the types of transducers exploited in the following part of the work. Then, in the context of functionalization techniques, the main advantages of Photochemical Immobilization Technique (PIT) over conventional methods are listed. In the final part of the Chapter, nanoparticles are introduced, focusing on AuNPs and MNPs@Au. In Chapter 2 is presented a magnetoelastic (ME) biosensor for wireless detection of analytes in liquid. A new amplification protocol exploiting MNPs@Au is demonstrated to significantly enhance the sensitivity. The superiority of MNPs@Au over AuNPs, has been demonstrated by testing the ME biosensor against Human IgG in the range 0–20 μg∙mL−1. The experimental results show that the ME biosensor works well in water and has a rapid response time, being promising for real-time wireless detection of pathogens in liquids and for real life diagnostic purposes. In Chapter 3 a simple, easy-to-use and efficient colorimetric immunosensor that exploits spinning MNPs@Au in a rotating magnetic field is presented. The proposed biosensor was tested against glyphosate in tap water, being able to detect the pesticide in concentration lower than the ones legally permitted in food according to several authorities. The excellent result in terms of sensitivity was achieved thanks to the adoption of MNPs@Au, as shown by the comparison made with the AuNPs based biosensor. This performance makes the colorimetric approach described in Chapter 3 an interesting tool for on-site detection or even POC diagnosis. In Chapter 4 is reported a fast, simple and effective protocol for coating commercial MNP clusters with AuNPs. The resulting core@satellite magnetic particles (CSMPs) consist of isolated gold nanoparticles stuck onto an aggregate of individual iron oxide crystals (core). The CSMPs were used in combination with a powerful MR biochip equipped with a unique highly-portable detection platform properly designed to achieve a POC device. The biosensing setup was tested against Human IgG at concentrations of clinical interest. The novel CSMPs have an enormous potential for excellent sensing applications, especially in the target protein quantitative detection field with quick response (within 1 hour), potential multiplexing analysis (up to 6 different analytes at the same time) and signal redundancy (up to 30 measurements). The global conclusions of the thesis work are summarized in the final remarks.

Downloads

Actions (login required)

View Item