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Superparamagnetic iron oxide nanoparticles (SPIONs) exhibit unique properties for diverse biomedical applications, including drug delivery and diagnostic imaging. Actively targeted SPIONs enhance delivery to diseased sites, reducing side effects and enhancing treatment efficacy. However, development of reproducible functionalization protocols is challenged by the erratic behavior of nanoparticles in suspensions, such as agglomeration and sedimentation. In this study, we develop and systematically optimize a functionalization method to attach the Fc-region of antibodies onto silica coated SPIONs via click chemistry, ensuring controlled ligand orientation on the particle surface. The synthesis and successive modifications of silica coated SPIONs with organic moieties is presented resulting in the final click conjugation with anti-ICAM1 antibodies. These antibodies target ICAM1, upregulated on epithelial cell surfaces during gastrointestinal inflammation. Thermogravimetric analysis and infrared spectroscopy confirm successful SPION functionalization after each modification step. Cell viability assessment indicates no adverse effects of bioconjugated particles. Quantitative elemental analysis reveals significantly higher iron concentration in inflammation-induced Caco-2 cells exposed to ICAM1-modified particles compared to non-conjugated counterparts. Furthermore, laser scanning confocal microscopy of these cells suggests surface interaction and internalization of bioconjugated SPIONs, underscoring their potential for targeted imaging and therapy in inflammatory diseases.

The identification of biomarkers overexpressed during inflammation is critical for targeting diagnostic or therapeutic agents to the inflamed intestine in inflammatory bowel disease (IBD). The first part of this thesis employs global proteomic analysis to identify preclinical IBD biomarkers using in vitro and in vivo models. The study focuses on apical plasma membrane biomarkers and secreted biomarkers, identifying promising targets for diagnostic imaging probes. Proteomic analysis quantified 7340 proteins across ileum, proximal, and distal colon samples in vivo, revealing significant protein concentration changes primarily in the colon after DSS treatment. Functional annotation linked these changes to inflammatory responses. In vitro analysis using Caco-2 cells treated with TNF-α identified 465 proteins involved in defense and cytokine responses, showing greater relevance for modeling inflammation than DSS-treated cells.

Key inflammatory biomarkers were identified, including TGM2, ICAM1, CEACAM1, and ANXA1, with varied upregulation across models. These biomarkers were validated via immunohistochemistry, showing consistent expression in inflamed and healthy tissues. Additionally, luminal and immune cell-associated proteins such as myeloperoxidase and calprotectin were identified, suggesting their potential for in situ quantitative assessment of IBD activity.

The second part of this thesis details the development of MRI-active biosensors using superparamagnetic iron oxide nanoparticles (SPIONs) functionalized via click chemistry with ligands targeting the identified biomarkers. The synthesis and characterization of SiO2-coated γ-Fe₂O₃ SPIONs and their subsequent functionalization with antibodies targeting ICAM1 were optimized for enhanced biocompatibility and targeting efficacy. In vitro studies demonstrated specific binding and internalization of bioconjugated SPIONs in inflamed Caco-2 cells.

The third part explores in vivo targeting efficacy of bioconjugated SPIONs in colitis-induced mice. Ceacam1-conjugated SPIONs showed significant binding to inflamed tissues, highlighting their potential for targeted imaging and therapeutic delivery in IBD. This thesis underscores the importance of systematic nanoparticle modification and characterization, advancing precision medicine and diagnostic technologies for IBD.

Superparamagnetic iron oxide nanoparticles (SPIONs) generate heat upon exposure to an alternating magnetic field (AMF), which has been studied for hyperthermia treatment and triggered drug release. This study introduces a novel application of magnetic hyperthermia to induce amorphization of a poorly aqueous soluble drug, celecoxib, in situ in tablets for oral administration. Poor aqueous solubility of many drug candidates is a major hurdle in oral drug development. A novel approach to overcome this challenge is in situ amorphization of crystalline drugs. This method facilitates amorphization by molecular dispersion of the drug in a polymeric network inside a tablet, circumventing the physical instability encountered during the manufacturing and storage of conventional amorphous solid dispersions. However, the current shortcomings of this approach include low drug loading, toxicity of excipients, and drug degradation. Here, doped SPIONs produced by flame spray pyrolysis are compacted with polyvinylpyrrolidone and celecoxib and exposed to an AMF in solid state. A design of experiments approach was used to investigate the effects of SPION composition (Zn_0.5Fe_2.5O₄ and Mn_0.5Fe_2.5O₄), doped SPION content (10–20 wt %), drug load (30–50 wt %), and duration of AMF (3–15 min) on the degree of drug amorphization. The degree of amorphization is strongly linked to the maximum tablet temperature achieved during the AMF exposure (r = 0.96), which depends on the SPION composition and content in the tablets. Complete amorphization is achieved with 20 wt % Mn_0.5Fe_2.5O₄ and 30 wt % celecoxib in the tablets that reached the maximum temperature of 165.2 °C after 15 min of AMF exposure. Furthermore, manganese ferrite exhibits no toxicity in human intestinal Caco-2 cell lines. The resulting maximum solubility of in situ amorphized celecoxib is 5 times higher than that of crystalline celecoxib in biorelevant intestinal fluid. This demonstrates the promising capability of SPIONs as enabling excipients to magnetically induce amorphization in situ in oral dosage forms.

Oral delivery is the preferred route of drug administration due to patient compliance and convenience. Despite this, nanomedicines have so far primarily been developed for the parenteral route. Inorganic nanoparticles hold great promise as theranostics for oral drug delivery. This is gaining importance especially for the local treatment of gastrointestinal (GI) diseases. However, successful oral delivery of inorganic nanoparticles is challenged by complex physiological conditions in the GI tract. We discuss the main GI barriers and their impact on nanoparticle biotransformation and toxicity. An improved understanding of the complex interplay of inorganic nanoparticles with the dynamic GI environment can facilitate the development of efficient oral nanomedicines.

Inflammatory bowel disease (IBD) is a chronic condition resulting in impaired intestinal homeostasis. Current practices for diagnosis of IBD are challenged by invasive, demanding procedures. We hypothesized that proteomics analysis could provide a powerful tool for identifying clinical biomarkers for non-invasive IBD diagnosis. Here, the global intestinal proteomes from commonly used in vitro and in vivo models of IBD were analyzed to identify apical and luminal proteins that can be targeted by orally delivered diagnostic agents. Global proteomics analysis revealed upregulated plasma membrane proteins in intestinal segments of proximal- and distal colon from dextran sulfate sodium-treated mice and also in inflamed human intestinal Caco-2 cells pretreated with pro-inflammatory agents. The upregulated colon proteins in mice were compared to the proteome of the healthy ileum, to ensure targeting of diagnostic agents to the inflamed colon. Promising target proteins for future investigations of non-invasive diagnosis of IBD were found in both systems and included Tgm2/TGM2, Icam1/ICAM1, Ceacam1/CEACAM1, and Anxa1/ANXA1. Ultimately, these findings will guide the selection of appropriate antibodies for surface functionalization of imaging agents aimed to target inflammatory biomarkers in situ.

Poor aqueous drug solubility represents a major challenge in oral drug delivery. A novel approach to overcome this challenge is drug amorphization inside a tablet, that is, on-demand drug amorphization. The amorphous form is a thermodynamically instable, disordered solid-state with increased dissolution rate and solubility compared to its crystalline counterpart. During on-demand drug amorphization, the drug molecularly disperses into a polymer to form an amorphous solid at elevated temperatures inside a tablet. This study investigates, for the first time, the utilization of photothermal plasmonic nanoparticles for on-demand drug amorphization as a new pharmaceutical application. For this, near-IR photothermal plasmonic nanoparticles were tableted together with a crystalline drug (celecoxib) and a polymer (polyvinylpyrrolidone). The tablets were subjected to a near-IR laser at different intensities and durations to study the rate of drug amorphization under each condition. During laser irradiation, the plasmonic nanoparticles homogeneously heated the tablet. The temperature was directly related to the rate and degree of amorphization. Exposure times as low as 180 s at 1.12 W cm(-2) laser intensity with only 0.25 wt % plasmonic nanoparticles and up to 50 wt % drug load resulted in complete drug amorphization. Therefore, near-IR photothermal plasmonic nanoparticles are promising excipients for on-demand drug amorphization with laser irradiation.