• Postdoctoral Fellow, University of California, San Diego
• NSF Postdoctoral Fellow, University of Bordeaux
• PhD, University of North Carolina – Chapel Hill
• BS, University of California, Santa Barbara

• Associate Editor, Inorganic Chemistry 2014-present
• CSO of Ferric Contrast, Inc. 2017-present
• Director NSF Research Experiences for Undergraduates 2005-2015

• Elected Fellow of the American Association for the Advancement of Science, 2020
• Larkin Chair, 2019-2024
• UB exceptional scholar (sustained achievement), 2015
• Jacob F. Schoellkopf Medal, ACS, 2014
• Co-chair of the NSF workshop in Inorganic Chemistry, 2010
• Elected council member, Society of Biological Inorganic Chemistry, 2009-2012
• National Science Foundation Award for Special Creativity, 2007-2009
• Chair, Bioinorganic chemistry section of the Inorganic division of the ACS, 2005
• Director, Research Experiences for Undergraduates Site in the Chemistry Department at the University at Buffalo, 2004-present
• NSF Visiting Professor, University of Rochester, 1996-1997
• Alfred P. Sloan Fellow, 1994-1996

The central theme in our research is the synthesis of inorganic complexes for biomedical diagnostics, sensing, or therapeutic applications.

Current research in our laboratories focuses on the following topics:

• Magnetic resonance imaging contrast agents containing iron, cobalt or nickel
• Temperature, pH or redox responsive MRI contrast agents for applications in tumor imaging
• Coordination cages for biomedical imaging and drug delivery

Magnetic resonance imaging probes that are responsive to biological environment

Paramagnetic metal ion complexes are widely used in clinical medicine as contrast agents for MRI. We have developed the first examples of paramagnetic transition metal complexes that act as chemical exchange saturation transfer agents (paraCEST). ParaCEST agents produce contrast that can be turned on and off with a presaturation pulse, eliminating the need for pre- and post-contrast agent MRI scans.

Metal ions with excellent magnetic properties for paraCEST include the biologically relevant metal ions Fe(II), Co(II) and Ni(II). We have prepared macrocyclic complexes of these metal ions that are inert towards dissociation and are in high spin form.  These complexes produce intense CEST contrast that is shifted far from the signal from bulk water in tissue.  To further increase signal, Co(II) complexes have been incorporated into liposomes to produce lipoCEST agents. Our paraCEST agents are sensitive to temperature and to pH and are under development for mapping temperature and pH in tissue.  Tuning the redox properties of the iron and cobalt complexes produces paraCEST agents that switch on and off according to redox potential.  More recently, we have prepared iron based T₁ agents that increase MRI signal in the presence of oxidants through Fe(II)/Fe(III) changes and Fe(III) probes that show increased relaxivity upon binding Zn(II) ions.

Iron(III) coordination complexes as alternatives to Gadolinium(II) MRI contrast agents

High spin Fe(III) complexes show great promise as contrast agents that increase relaxation of water protons for T₁ weighted MRI. Our group has produced a new class of macrocyclic Fe(III) complexes that produce water proton relaxivity in serum that rivals that of clinically used Gd(III) complexes. These iron complexes do not have a rapidly exchanging water ligand, but function through second-sphere water interactions and through proton exchange. 

The synthetic chemistry of the Fe(III) macrocyclic complexes is quite versatile, allowing us to change ancillary groups to tune the biodistribution and pharmacokinetics of clearance from mice. The overall charge and lipophilicity of the complexes is varied to produce a strong signal in the vasculature and for rapid renal clearance.  Complexes that bind tightly to serum albumin for use as blood pool agents are also being studied. These complexes are being further developed and tested in vivo in collaboration with Roswell Park Comprehensive Cancer Center imaging scientists. 

Yeast-derived Β-glucan particles (GPs) are hollow shells that act as carriers for drugs and imaging probes. The GPs are promising for targeting immune cells including macrophages and monocytes.  Fe(III) complexes with open coordination sites bind strongly to GPs  and are released upon treatment with mild acid or a chelator. The iron-loaded GPs are taken up by macrophages, opening up the possibility of targeting macrophages in tumors for imaging.

Coordination cages for biomedical imaging and drug delivery

An approach to further increase the signal from the paramagnetic probe involves the incorporation of multiple centers in a coordination cage. Our initial studies used the tetrahedral iron(III) cages originally developed by the Raymond group. The four rigidly-connected iron centers in the anionic cage produce a high relaxivity MRI probe. The naphthyl groups enable binding to serum albumin to give a blood pool agent that accumulates in tumors. Recent studies show that gold metallodrugs act as guests within the cage under biological conditions. These Au(I) complexes are solubilized in aqueous solution and produce a unique biodistribution upon intravenous injection in animals, including increased tumor uptake.  Studies are underway to examine the theragnostic potential of these agents and new cages are under development with six metal centers.

• Dissanayake, A.  Spernyak, J. A.; Morrow, J. R.* “An Octahedral Coordination Cage with Six Fe(III) Centers as a T₁ MRI Probe” Chem. Commun. 2024, DOI:10.1039/D4CC03681F.
• Sahoo, P. R.: Spernyak, J. A.; Morrow, J. R.* “Self-assembled Iron(III) Coordination Cage as an MRI-active Carrier for a Gold(I) Drug” Bioconj. Chem.2024,  DOI:10.1021/acs.bioconjchem.4c00391
• Raymond, J. J.; Chowdhury, Md. Saiful, Crawley, M. R.; Morrow, J. R.* “Co(II) Macrocyclic Complexes with Amide-Glycinate Pendants as ParaCEST and Liposomal CEST Agents” Chem. Eur. J. 2024, DOI:10.1002/chem.202401638
• Kras, E. A.; Cineus, R.; Crowley, M. R.: Morrow, J. R.*  “Macrocyclic complexes of Fe(III) with mixed hydroxypropyl and phenolate or amide pendants as T₁ MRI probes”  Dalton Trans. 2024, 53, 4154-4164. DOI:10.1039/d3dt04013e.
• Cineus, Roy; Abozeid, S. M.; Sokolow, G. E.; Spernyak, J. A.; Morrow, J. R.* “Fe(III) T₁ MRI probes containing phenolate or hydroxypyridine-appended triamine chelates and a coordination site for bound water” Inorg. Chem. 2023, 62, 16513-16522. DOI:10.1021/acs.inorgchem.3c02344
  
• Chowdhury, M. S. I.; Kras, E. K.; Turowski, S. G.; Spernyak, J. A.; Morrow, J. R.* “Liposomal MRI probes containing encapsulated or amphiphilic Fe(III) coordination complexes” Biomater. Sci. 2023, 11, 5942-5954. DOI:10.1039/d3bm00029J
  
• Raymond, J. J.: Abozeid, S. M.; Sokolow, G. E.; Bond, C. J.; Yap, C. E.; Nazarenko, A. Y.; Morrow, J. R.* “Co(II) complexes of tetraazamacrocycles appended with amide or hydroypropyl groups as paraCEST agents” Dalton Trans., 2023, 52, 9831-9839. DOI:10.1039/d3dt01572f
  
• Sokolow, G. E.; Crawley, M. R.; Morphet, D. R.; Asik, D.;  Spernyak, J. A.; McGray, J. R.; Cook, T. R.*; Morrow, J. R.* “Metal-organic polyhedron with four Fe(III) centers producing enhanced T1 magnetic resonance imaging contrast in tumors” Inorg. Chem. 2022, 61, 2603-2011. DOI:10.1021/acs.inorgchem.1c03660
  
• Pinti, J. C.; Kras, E. A.; Patel, A.; Schrier, C. L.; Stoj, C. S.; Morrow, J. R. “Magnetization of yeast by labeling with iron complexes: An undergraduate laboratory experiment” J. Chem. Educ. 2022, 99, 3752-3756. DOI:10.1021/acs.jchemed.2c00791
  
• Morrow, J. R.;* Raymond, J. D.; Chowdhury, M. S. I.; Sahoo, P. R. “Redox-responsive MRI probes based on first-row transition metal complexes” Inorg. Chem. 2022, 61, 14487-14499. DOI:10.1021/acs.inorgchem.2c02197
• Kras, E.; Snyder, E.; Sokolow, G. E.; Morrow, J. R. “Distinct coordination chemistry of Fe(III)-based MRI probes” Acc. Chem. Res. 2022, 55, 1435-1444. DOI:10.1021/acs.accounts.2c00102
  
• Asik, D. A.; Abozeid, S. M.; Turoski, S. G.; Spernyak, J. A.; Morrow, J. R.* “Dinuclear Fe(III) hydroxypropyl-appended macrocyclic complexes as MRI probes” Inorg. Chem. 2021, 60, 8651-8664. DOI:10.1021/acs.inorgchem.1c00634 
  
• Kras, E. A.; Abozeid, S. M.; Eduardo, W.; Spernyak, J. A.; Morrow, J. R.* “Comparison of phosphonate, hydroxypropyl and carboxylate pendants in Fe(III) macrocyclic complexes as MRI contrast agents” J. Inorg. Biochem. 2021, 225, 111594. DOI:10.1016/j.jinorgbio.2021.111594
• Abozeid, S. M.; Chowdhury, Md. S. I.; Asik, D.; Spernyak, J.A.; Morrow, J. R. “Liposomal Fe(III) macrocyclic complexes with hydroxypropyl pendants as MRI probes” ACS Appl. Bio Mater. 2021, 4, 7951-7960. DOI:10.1021/acsabm.1c00879
  
• Snyder, E. M.; Asik, D.; Abozeid, S. M.; Burgio, A.; Bateman, G.; Turowski, S. G.; Spernyak, J. A.; Morrow, J. R.* “A class of Fe(III) macrocyclic complexes with alcohol donor groups as effective T1 MRI contrast agents” Angew. Chem. Int. Ed. 2020, 59, 2414-2419. PMID:31725934. DOI:10.1002/anie.201912273
• Bond, C. J.; Cineus, R.; Nazarenko, A. Y.; Spernyak, J. A.; Morrow, J. R.* “Isomeric Co(II) paraCEST agents as pH responsive MRI probes” Dalton Trans. 2020, 49, 279-284. PMID: 23102112. DOI:10.1039/C9DT04558A
  
• Snyder, E. M.; Chowdhury, M. S. I.; Morrow, J. R.* “Co(II) and Fe(II) Triazole-appended 4,10-diaza-15-crown-5-ether macrocyclic complexes for CEST MRI applications” Inorg. Chim. Acta 2020, 509, 119649. issue in honor of Prof. Tara Dasgupta. DOI:10.1016/j.ica.2020.119649
• Patel, A.; Asik, D. Snyder, E. M.; Delillo, A. E.; Cullen, P. J.; Morrow, J. R.* “Binding and release of Fe(III) complexes from glucan particles for the delivery of T1 MRI contrast agents” ChemMedChem 2020, March 13. PMID:32168421. DOI:10.1002/cmdc.202000003
• Abozeid, S. M.; Asik, D.; Sokolow, G. E.; Nazarenko, A. Y.; Lovell, J. F.; Morrow, J. R. “Co(II) complexes as liposomal CEST agents” Angew. Chem. Int. Ed.  2020, 59, 12093-12097. DOI:10.1002/anie.202003479
• Asik, D.; Smolinski, R.; Abozeid, S. M.; Michell, T. B.; Spernyak, J. A.; Morrow, J. R. “Modulating the properties of Fe(III) macrocyclic MRI contrast agents by appending sulfonate or hydroxyl groups”  Molecules 2020, 25, 2291. DOI:10.3390/molecules25102291
• Patel, A.; Patel, A. Asik, D. Snyder, E. M.; Apernyak, J. A.; Cullen, P. J.; Morrow, J. R.* “Saccharomyces cerevisiae and Candida albicans yeast cells labeled with Fe(III) complexes as MRI probes” Magnetochemistry 2020, 6, 41. DOI:10.3390/magnetochemistry6030041
• Patel, A.; Patel, Abozeid, S. M.; Cullen, P. J.; Morrow, J. R.* “Co(II) macrocyclic complexes appended with fluorophores as paraCEST and cell CEST agents” Inorg. Chem. 2020, 59, 16531-16544. DOI:10.1021/acs.inorgchem.0c02470
• Bond, C. F.; Sokolow, G. E.; Crawley, M. R.; Burns, P. J.; Cox, J. M.; Mayilmurugan, R.; Morrow, J. R.* “Exploring inner-sphere water interactions of Fe(II), Fe(II) and Co(II) complexes of 12-member macrocycles to develop CEST MRI probes” Inorg. Chem. 2019, 58, 8710-8719. PMID:31247845. DOI: 10.1021/acs.inorgchem.9b01072
• Patel, A.; Asik, D.; Spernyak, J. A.; Cullen, P.; Morrow, J. R.* “MRI and fluorescence studies of Saccharomyces cerevisiae loaded with a bimodal Fe(III) T1 contrast agent” J. Inorg. Biochem. 2019, 201, 110832. Issue dedicated to Debbie Crans. PMID:31522137, PMID: PMC6859208, DOI: 10.1016/j.jinorgbio.2019.110832
• Tsitovich, P. B.; Tittiris, T. Y.; Cox, J. M.; Benedict, J. B.;  Morrow, J. R.* “Fe(II) and Co(II) N-methylated CYCLEN complexes as paraSHIFT agents with large temperature dependent shifts” Dalton Trans. 2018, 47, 916-924. PMID: 29260180, DOI:10.1039/c7dt03812g
• Abozeid, S. M.; Snyder, E. M.;  Tittiris, T. Y.; Steuerwald, C.M.; Nazarenko, A. Y.; Morrow, J. R.* “Co(II) complexes with innersphere and outersphere water interactions for CEST MRI applications” Inorg. Chem. 2018, 57, 2085-2095. PMID: 29412653, DOI:10.1021/acs.inorgchem.7b02977
• Abozeid, S. M.; Snyder E. M.;  Lopez, A. P.; Steuerwald, C. M.; Sylvester, E.;  Ibrahim, K. M;  Zaky, R. R; Abou-El-Nadar, H. M.; Morrow, J. R.* “Nickel(II) complexes as paramagnetic shift and paraCEST agents” Eur. J. Inorg. Chem. 2018, 1902-1908. DOI:10.1002/ejic.201800021
• Tsitovich, P. B.;  Gendron F.; Nazarenko, A. Y.; Livesay, B. N.; Lopez, A. P.; Shores, M. P.; Autschbach, J. A.; Morrow, J. R.* “Low-spin Fe(III) macrocyclic complexes of imidazole-appended TACN as paramagnetic probes” Inorg. Chem. 2018, 57, 8364-8374. PMID:29939736, DOI:10.1021/acs.inorgchem.8b01022
• Burns, P. J.; Cox, J. M.; Morrow, J. R.* “Imidazole-appended macrocyclic complexes of Fe(II), Co(II) and Ni(II) as paraCEST agents” Inorg. Chem. 2017, 56, 4545-4554. PMID:28358208, DOI:10.1021/acs.inorgchem.7b00176
• Tsitovich,  P. B.; Kosswattaarachchi, A. M.; Crawley, M. R.; Tittiris, T. Y.; Cook, T. R.;* Morrow, J. R.* ”An Fe(III) aza-macrocyclic complex as pH-tunable catholyte and anolyte for redox-flow battery applications” Chem. Eur. J. 2017, 23, 15327-15331. PMID:28929548, DOI:10.1002/chem.201704381
• Tsitovich, P. B.; Cox. J. M.; Morrow, J. R.* “Gear up for a pH shift: A responsive iron(II) 2-amino-6-picolyl-appendent macrocyclic paraCEST agent that protonates at a pendent group” Inorg. Chem. 2016, 55, 12001-12010. PMID: 27934305 DOI:10.1021/acs.inorgchem.6b02159
• Sanders, S. A; Morrow, J. R.* “Zn(II) Complexes that trigger a DNA conformational Switch” Submitted to special issue on metal nucleic acid interactions: state of the art in Inorg. Chim. Acta 2016, 452, 90-97. DOI:10.1016/j.ica.2016.02.008
• Burns, P. J.; Tsitovich, P. B.; Morrow, J. R.* “Preparation of Cobalt(II) Cages: An Undergraduate Laboratory Experiment that Produces a paraSHIFT  Agent for Magnetic Resonance Spectroscopy” J. Chem. Educ. 2016, 93, 1115-1119. DOI:10.1021/acs.jchemed.5b00818