Developing experimental design and analysis skills in Biomedical Engineering. A laboratory experiment proposal

Abstract

[EN] Learning-teaching process in the area of Biomedical Engineering requires the acquisition of skills related to the formulation and resolution of problems in biology and medicine through the use of innovative technologies, and the ability to effectively use biomedical instrumentation and the processing and analyzing methods for studying the complex systems and processes of the human body. In order to deepen the acquisition of some omics-related disciplines, the objective of the present work is the development of a laboratory experiment in the field of molecular imaging, whose purpose is the metabolomic study (acquisition and data processing) of biological samples by Nuclear Magnetic Resonance (NMR) spectroscopy. The proposed laboratory experiment is carried out in groups of 15 students and it is structured in two different sessions. The first session is held at the facilities of the Molecular and Metabolomic Imaging Laboratory of the Unitat Central d¿Investigació de Medicina of University of Valencia, and during the session each student performs the sample collection and treatment of their own biological sample (urine), whose metabolomic study is desired, following the appropriate laboratory protocol. After preparation, the acquisition of the NMR spectra corresponding to each of the samples is carried out. All students introduce their samples into the NMR spectrometer and observe the different phases of the acquisition process (frequency tuning and matching, sequence specification, pulse calculation, etc.) to obtain the NMR spectrum. In the second session, which takes place in a computer classroom of the Universitat Politècnica de València, the purpose is the use of different methods of analysis and observation to identify and quantify the metabolites from the NMR spectra acquired during the first session. Firstly, signal processing techniques are used to process the NMR spectra (phase correction, baseline correction and spectrum reference), and then a total of 10 selected metabolites contained in the urine are quantified, using specific software for its application to the field of metabolomics. Finally, the students create a table that collects the data of the subjects (themselves, anonimized) and metabolite concentration, and perform the multivariate statistical analysis: principal component analysis (PCA) and partial least squares discriminant analysis (PLSDA). Through the performed analysis, each student establishes one metabolic profile and obtains conclusions from it, such as the determination of a characteristic metabolomic fingerprint associated with variables such as the sex of the person providing the sample, or the determination of a smoker profile, among others. Through the completion of the proposed laboratory experiment, students will acquire general and specific outcomes in the Biomedical Engineering field: 1) implementation and management of adequate experiments (preparation of biological samples), 2) use of innovative technologies (process of acquisition of NMR spectra), 3) application of scientific methods to perform the analysis of data (signal processing), 4) selection and performance of observation methods (statistical analysis) to assess the results and build conclusions, 5) to carry out a simple metabolic study that allows to verify the metabolic impact of some variable as smoking, and 6) to propose new working hypotheses based on the results obtained and expected results.