Dr. Facundo Fernandez
Assistant Professor, School of Chemistry and Biochemistry
Ph.D., Buenos Aires University
Phone: (404) 385-4432
Fax: (404) 894-7452
Office:
Research Interests
The recent award of the Nobel Prize in Chemistry to John B. Fenn (for the discovery of electrospray ionization) and to Koichi Tanaka (for the discovery of Matrix Assisted Laser Desorption/Ionization) clearly states that analytical mass spectrometry plays a central role on the on-going revolution in the Biological and Biomedical Sciences. Research in the Fernandez Lab focuses on the development of novel bioanalytical mass spectrometric techniques to solve complex biomedical and environmental scientific questions. The experiments involve state-of-the-art time-of-flight analyzers, ion mobility spectrometry, MEMS nanospray ion sources, atmospheric pressure MALDI ionization and the mining of the obtained data using chemometric tools such as multivariate calibration and clustering and genetic algorithm variable selection.
Mass Spectrometry in Tropical Disease Research. Mosquito Peptidomics and Counterfeit Drug Detection: Malaria is the most important tropical disease, remaining widespread throughout the tropics, but also occurring in many temperate regions. Plasmodium falciparum, a protozoan parasite that is injected into the blood stream during the bite of a widespread specie of mosquito (Anopheles gambiae) is the main cause of severe clinical malaria. Several other parasite strains also cause malaria (P. vivax, P.malariae and P. ovale). Dengue fever, another widespread tropical disease, is also transmitted by a particular mosquito species (Aedes aegypti). Mass Spectrometry has many analytical advantages that can be used in tropical disease diagnosis, prevention and research. In this trend, we are collaborating with Prof. Fernando Noriega from Florida International University in the study of novel ways of controlling the malaria and dengue fever mosquito transmission vectors through the functional proteomic analysis of the mosquito neuroendocrine system. To date, there are no effective vaccines to prevent malaria in humans. Prevention and treatment of malaria thus still depends on potent antimalarial drugs. In recent years, large numbers of counterfeit antimalarial drugs have been detected. In collaboration with researchers from the CDC and from the Oxford University-Wellcome Trust program in SE Asia, we are working on producing molecular signatures of such counterfeits using direct atmospheric-pressure ionization methods based on Desorption Electrospray Ionization and Penning ionization with metastable He atoms. These rapid screening techniques not only allow us to screen for the expected active ingredients but also to chemically fingerprint counterfeit samples in order to track their origin.
Environmental Mass Spectrometry. Study of the Biogeochemical Cycling of Fe: Plankton plays a crucial role in the Earth's life dynamics; this tiny organisms lie at the bottom of the aquatic food chain, and its fate is thus thought to have deep implications in global climate change. Iron, among other trace metals, is an indispensable nutrient for the production of plankton, the most abundant marine organism. Because iron is extremely scarce in surface seawater, it is thought to occur almost exclusively bound to complex ligands of biological origin. While exquisitely sensitive, existing field analysis techniques for organic-bound metals are unable to resolve the nature of the ligands. Mass Spectrometry is one of the key analytical methods used to identify and characterize small quantities of biological molecules embedded in complex matrices. Although MS has found widespread use in laboratory applications, technical improvements in instrumentation are needed to extend its application to the grand challenges that face the environmental sciences. In collaboration with Stanford University and the Scripps Institute of Oceanography we are developing instrumentation based on high resolution Ion-Mobility Spectrometry-Time-of-Flight Mass Spectrometry (IMS-TOF-MS) for investigating poorly understood aspects of the iron biogeochemical cycle such as: (1) the role of Fe in the photochemical reactivity of surface water Chromophoric Dissolved Organic Matter (CDOM); (2) the influence of Fe complexation by tetrapyrroles in its role as a micronutrient in marine systems; and (3) study of the biogeochemical fate of iron associated with heme and iron-sulfur moieties in metallo-proteins. In this trend, we are developing key component of the proposed MS technology such as MEMS Bradbury-Nielsen ion gates and monolithic resistive glass ion mobility drift tubes for fast analytical separations.
Mass Spectrometry in Pathogen identification and Counterterrorism: Accurate and rapid bacterial identification is important in diagnosing disease, assessing public health and bioterrorism prevention. Many studies have shown that matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is a promising technique for the fast identification of whole microorganisms. Generally, two approaches have been adopted for microorganism identification. The most robust and time-intensive approach relies on the sequencing of protein biomarkers using MS/MS-based proteomic techniques. A faster, complementary approach relies on pattern recognition of the protein biomarker fingerprint obtained by MALDI. In this direction, we are collaborating with Dr. John Barr and Dr. Hercules Moura from CDC Atlanta to develop new identification schemes for Coxiella burnetii, the pathogen causative of Q-fever. These methods are based on Partial Least Squares Discriminant Analysis and MALDI TOF MS and allow us to rapidly distinguish between different C. burnetii strains. In collaboration with Prof. Andrei Fedorov and Prof. Levent Degertekin from the Woodruff School of Mechanical Engineering at Georgia Tech we are developing alternative strategies to MALDI-based microorganism identification based on a novel Array of Micromachined UltraSonic Electrospray emitters ("AMUSE").