Considered one of the fundamental branches of chemistry, in the last decades analytical chemistry has experienced continuous growth in other scientific areas. Drifting away from its “standard” domain, it has found applications in other disciplines, with a particularly strong impact in the life sciences.
Chemistry. Image Credit: Romolo Tavani/Shutterstock.com
Analytical chemistry involves the separation, identification, and quantification of analytes in a given sample under investigation. Information is obtained in different ways, often complementary: through qualitative analysis that identifies whether a substance is present or not, while its amount is determined through quantitative analysis.
Advances in technology and scientific knowledge, both from within chemistry itself and from other physical and natural sciences (i.e. physics and biology), led to the involvement of analytical chemistry in an increasing number of tasks. Over the years, the discipline moved away from a chemistry-oriented field of research, towards more broadly defined cross-disciplinary areas.
Therefore, while chemistry is still the science at the core, applications in chemical analysis range over the entire scientific realm. Of special interest has been the application of analytical chemistry to the life sciences, such as biology, biotechnology, and biomedical research.
Mass spectrometry for the analysis of complex systems
Mass spectrometry (MS) – which measures the mass-to-charge ratio (m/z) of ions in the gas phase – has experienced a tremendously large growth in its uses for extensive applications in complex biological sample analysis.
MS is capable of identifying trace amounts of biomolecules in complex matrices with high sensitivity and specificity, and it can be used to characterize a wide variety of biomolecules, such as sugars, proteins, and oligonucleotides. In addition to providing information on the molecular weight, it is also possible for instance to resolve the primary sequence of peptides and proteins through high-resolution MS and tandem MS, respectively.
While in the past, clinical diagnostics has strongly relied on antibody-based detection strategies, MS is now emerging as a powerful method to gather insights into changes of the proteome, contributing to advance personalized medicine.
MS is also a valuable tool in the high-throughput analysis of compounds generated in combinatorial libraries, such as those created for the discovery of new drugs.
Spectroscopic techniques for biomedical research
While still very much associated with the traditional concept of the analytical chemistry lab, spectroscopy has found its way into the biological and medical fields. Contributing factors are the possibility to use very small volumes of sample, as well as being non-invasive.
Preclinical and clinical studies are being conducted to measure physiological changes across a variety of organ sites and applications in drug discovery and assessment of response to cancer therapy, to name a few, as well as screening and diagnostic applications in different cancers, such as breast and cervical cancer.
Fluorescence has shown potential applications in gastroenterology, for endoscopic in vivo detection of early carcinoma in the upper gastrointestinal tract and for detecting benign and malignant lesions in the stomach mucosa.
Moreover, a study showed the potential in monitoring and predicting therapeutic response when nanoparticles conjugated with a fluorophore are used as drug carriers. In this case, physiologic changes induced by hyperthermia, and treatment with doxorubicin encapsulated in low-temperature sensitive liposome (LTSL) nanoparticles, were evaluated by UV spectroscopy.
The ability to characterize drug delivery and tumor physiology in vivo make this a potentially useful tool for evaluating the efficacy of targeted delivery systems in preclinical studies.
Nuclear Magnetic Resonance for metabonomics and imaging
Nuclear Magnetic Resonance (NMR) is one of the techniques of choice for investigating the structures of biomacromolecules such as proteins or to elucidate the structure and function of other biological components, like receptors.
NMR methods have been developed to obtain structural and dynamic information on the interactions between glycosaminoglycan (GAG) and proteins. These analyses provide valuable insights for the creation of molecular models to better understand the structure-activity relationship of GAP-protein interactions.
In addition, NMR has found application in metabonomics to measure the dynamic multiparametric response of a living system’s metabolome to genetic modifications or pathophysiological stimuli. The analysis was performed with pattern recognition techniques to look for metabolic changes concerning the status of a disease or in response to external intervention.
Moreover, being non-invasive and non-destructive, the NMR imaging technique for diagnostic purposes, known as magnetic resonance imaging (MRI), has become predominant in medical diagnostics for imaging soft tissues (i.e. brain, heart, and muscle tissue), and tumor discovery in organs. It is now almost four decades that the technique has been routinely introduced in clinical practice.
Analytical chemistry today addresses problems of growing complexity, enabling great progress in the life sciences, from drug design to medical diagnosis and molecular and cellular biology.
Nevertheless, there is still much to do to enable the understanding of the chemistry underlying biological functions and truly elucidate the molecular basis of disease and health. There is a need for analytical techniques offering much greater speed, selectivity, spatial and temporal resolution, to explore the full chemical complexity of these systems.
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