Functionalized bismuth ferrite harmonic nanoparticles for cancer cells labelling and imaging

Bismuth ferrite (BFO) harmonic nanoparticles (NPs) display high nonlinear optical efficiency and excellent biocompatibility profile which make them attractive for the development of diagnostic applications as contrast agents. In this study, we present a general method for the functionalization of this material with chemical ligands targeting cancer molecular biomarkers. In particular, a conjugation protocol based on click reaction between alkynyl containing targeting ligands and poly(ethylene glycol) coated BFO NPs (67.7 nm) displaying surface reactive azido groups was developed. Copper-free click reaction allowed fast and efficient conjugation of a covalent inhibitor of prolyl-specific endopeptidases to coated BFO NPs. The ability of these functionalized nanomaterials (134.2 nm) to act as imaging probes for cancer cells was demonstrated by the selective labelling of human lung cancer cells.

Surface functionalization of metal oxide harmonic nanoparticles for targeted cancer imaging

Raphaël Jovita De Matos

Cancer is a major health burden worldwide and the leading cause of death in industrialized countries. Early detection is a primary factor of survival and remission rate. Classical imaging methods such as magnetic resonance imaging, ultrasound imaging and microscopy lack in sensitivity for early detection of precancerous lesions. Recent and rapid progresses in nanotechnologies have paved the way for the development of new tools for diagnosis and targeted treatment of cancer. Taking advantage of their surface properties for post-conjugation coupled to their optical characteristics, nanoparticles could provide new level of sensitivity for the detection and imaging of tumors. The investigation of functionalization of nanoparticles with small molecules for the targeting of cancer biomarkers was thus an important aim of this thesis. Secondly, the synthesis of a new multimodal probe coupling magnetic resonance imaging and multiphoton microscopy was also investigated. This work focuses on the development and application of synthetic pathways for small molecules targeting neoplastic cells and tumor microenvironment. Erlotinib and an inhibitor of fibroblast activation protein Î± were selected for their specific interactions with the epithelial growth factor receptor, present on the surface of lung cancer cells, and cancer-associated fibroblasts respectively. Those molecules where first modified with a biotin residue to assess their biocompatibility and their affinity for the targeted biomarker. The targeting ligands were further equipped with a cyclooctyne moiety for coupling with coated nanoparticles through bioorthogonal reaction. Nanoparticles based on non-centrosymmetric crystals were selected for their optical properties. Polymeric or inorganic coating, based on poly(ethylene glycol) derivatives and (3-aminopropyl)triethoxysilane respectively, were applied to decorate the nanomaterials with azide moieties. The resulting azides were used to perform copper-free click reaction with the modified targeting ligands. The conjugated nanoparticles where then assessed for their selective association to the targeted biomarker. Nanoparticles decorated with an inhibitor of fibroblast activation protein Î± revealed target-specific association to the enzyme. In vitro investigation of the association of Erlotinib-tagged nanoparticles to epithelial growth factor receptor positive cells is ongoing. Finally, a gadolinium complex was modified with an alkyne functional group for copper-catalyzed [3 + 2]-cycloaddition to the surface of coated nanoparticles. The functionalized nanoparticles were further assessed for their efficiency as magnetic resonance imaging contrast agent. Results revealed that conjugation of the gadolinium complex to the nanomaterial afforded a potent T1 contrast agent without affecting its optical properties. To summarize, several nanosystems were prepared through bioorthogonal reactions. The first part of this thesis presents the synthesis of two small molecules and subsequent coupling to coated nanoparticles for targeted tumor imaging. The second part of this work, discusses the preparation of a new multimodal device for magnetic resonance imaging coupled to multiphoton microscopy. Those nanoprobes may provide new sensitivity levels for the study and the early detection of cancers.

EPFL2020

Functionalization of Nanoparticles for Targeted Cancer Imaging and Diagnosis

Solène Marcelle Françoise Marie Passemard

At present time, cancer is the leading cause of death in developed countries. The medical imaging tools currently used in clinics such as radiology, nuclear magnetic resonance imaging, microscopy and endoscopy are not able to reach the sensitivity necessary to detect cancers in their earliest stages. The detection and identification of rare circulating individual cells and early cancer metastasis is of the utmost importance to reduce cancer mortality. The development of nanotechnology-based medical diagnostic tools could provide a qualitatively new level of sensitivity and accuracy for the detection of malignant diseases. In this project, the synthesis of functionalized nanoparticles with small targeting molecules that can capture cell entities for the detection of breast, lung and prostate cancers was thus investigated. The research project focused on the chemical development of coated and functionalized second harmonic nanoparticles, displaying unique optical properties. First, the synthesis of hetero-bifunctional poly(ethylene glycol) (PEG) able to covalently coat the nanomaterial and bind to the targeting molecules was performed. The coating of nanoparticles with α-triethoxysilyl-ω-azido and -ω-amino PEG was evaluated on iron oxide nanoparticles (IO NPs) as proof of concept. Coated NPs demonstrated to be non-cytotoxic and stable overtime in biological medium. Similar results were obtained with bismuth iron oxide NPs (BFO NPs) expressing second harmonic generation property. The functionalization of coated NPs was then established with drugs and ligands to specifically target cancer cells biomarkers. Preliminary modification of the selected ligands (e.g. c(RGDfK), Erlotinib, Lapatinib, and an inhibitor of prolyl-endopeptidases) with spacers and a biotin label was undertaken in order to assess their binding specificity to tumor cells. The two best candidates, c(RGDfK) and the inhibitor of prolyl-endopeptidases were modified to contain a simple or strain-cyclic alkyne for the conjugation to the NP's surface through bioorthogonal click reactions. Biological evaluations demonstrated that the ligand-functionalized IO and BFO NPs bind to human cancer cells through target-specific interactions. In summary, chemical modifications of nanoparticles were implemented using two different materials and several targeting ligands, demonstrating the flexibility of this methodology. Functionalized NPs were demonstrated to be biocompatible, stable over-time and suitable for the labelling of cancer cells through specific interactions with extracellular biomarkers overexpressed in tumors.

EPFL2014

Cellular uptake and biocompatibility of bismuth ferrite harmonic advanced nanoparticles

Luigi Bonacina, Sandrine Gerber, Stephanie Hwu, Solène Marcelle Françoise Marie Passemard, Daniel Rytz, Jean-Pierre Wolf

Bismuth Ferrite (BFO) nanoparticles (BFO-NP) display interesting optical (nonlinear response) and magnetic properties which make them amenable for bio-oriented diagnostic applications as intra- and extra membrane contrast agents. Due to the relatively recent availability of this material in well dispersed nanometric form, its biocompatibility was not known to date. In this study, we present a thorough assessment of the effects of in vitro exposure of human adenocarcinoma (A549), lung squamous carcinoma (NCI-H520), and acute monocytic leukemia (THP-1) cell lines to uncoated and poly(ethylene glycol)-coated BFO-NP in the form of cytotoxicity, haemolytic response and biocompatibility. Our results support the attractiveness of the functional-BFO towards biomedical applications focused on advanced diagnostic imaging.