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. Common for the identified proteins is that they can be targeted from the luminal side of the gastrointestinal tract. Thus, compared to serum biomarkers, they are specific for intestinal inflammation. To validate the clinical relevance of the biomarkers identified in our preclinical models, we are currently in the process of collecting intestinal biopsies from pediatric and adolescent IBD patients. Samples are collected from six regions (stomach, proximal and distal small intestine, ascending, transverse and descending large intestine) in the gastrointestinal tract during routine endoscopic procedures. The future bioanalysis of these samples will give us unique information about biomarker expression in different regions of the gastrointestinal tract during inflammation and we will also be able to compare the impact of patient age on the disease state.
The identified preclinical and clinical biomarkers, will be used as anchor points for imaging nanoparticles. With this approach, we aim to provide non-invasive, local and quantitative IBD diagnosis. Towards this end, we are working on manufacturing approaches for nanoparticles suitable for imaging by e.g. magnetic resonance imaging (MRI). Key experts in the field of nanomedicine have consistently emphasized the necessity for controllable, reproducible and scalable nanoparticle synthesis methods to accelerate broad clinical translation of nanomedicines. Thus, we produce our nanoparticles by flame spray pyrolysis (FSP), a scalable technique with excellent reproducibility. Furthermore, to ensure optimal and reproducible performance of the final product, we employ quality-by-design (Qbd) pharmaceutical manufacturing principles during nanoparticle development. We have produced an array of superparamagnetic iron oxide nanoparticle (SPION) compositions and sizes and systematically studied their impact on magnetic hyperthermia performance. The, to the best of our knowledge, unprecedented large dataset generated here combined with its modelling using design of experiments (DoE) enables us to i) systematically correlate physicochemical properties of nanoparticles with their hyperthermia performance and ii) identify an optimal operating space for high-performance SPIONs. We stipulate that the rigorous application of QbD principles and statistical DoE for engineering our nanoparticles can accelerate regulatory approval and support industrial translation of novel nanomedicines. This approach mitigates the risk of discontinued clinical trials arising from unreliable production processes.
We have applied click chemistry-based bioconjugation approaches to functionalize our nanoparticles with ligands targeting biomarkers in our preclinical IBD models. Click chemistry enables control of the antibody orientation on the particle surface, ensuring exposure of the active site. Our findings suggest that click chemistry allows simple and controlled bioconjugation of ligands onto SiO2-coated SPION surfaces, which enables the development of efficient and targeted MRI-contrast agents for IBD. First results indicate increased cellular uptake in vitro and enhanced binding in inflamed tissue compared to the healthy control in vivo for the functionalized nanoparticles. We are now also developing magnetic biosensors incorporating the functionalized nanoparticles. The biosensors will be used to quantify IBD disease activity in situ in the gastrointestinal tract by MRI. In order to achieve this goal, we have to improve our understanding of how gastrointestinal pathologies may affect nanoparticle stability and physicochemical properties after oral administration. For example, it has been reported that normal pH values, osmolality, and lecithin concentration in the gastrointestinal tract can dramatically change when patients suffer from IBD. To study the dynamic phenomena occurring during nanoparticle transport through the gastrointestinal tract, we have developed a microfluidic device, that can in a miniaturized format generate information about how the stability, aggregation, and protein corona formation around inorganic nanoparticles evolve during their passage through the gastrointestinal tract.
Our final goal is also to develop oral drug delivery systems that enable the local treatment of IBD. Here, we are exploring various indigenous and exogenous triggers that can be used to locally release drugs in the gastrointestinal tract. We specifically focus on biological drugs that are used in the treatment of moderate to severe cases of IBD and where today there is a lack of patient compliant treatments specifically tailored for pediatric patients. For this, we have developed drug formulations that can be 3D printed into solid oral dosage forms. Here, 3D printing enables the personalization of the dose for pediatric patients.
