Ryan Research Group

One of the most prolific, intriguing, and vitally important areas of contemporary scientific research involves cancer: studying potential causes of it, elucidating new mechanisms by which it develops and sustains itself, and, ultimately, searching for innovative techniques to detect and selectively destroy it. Moreover, there is a distinct need for novel approaches to intracellular drug delivery in general. Whether one intends to activate/suppress/change a given gene in a particular cell, deliver a therapeutic molecule to a specific organelle within a cell, or even if one merely wants to probe a cellular process of interest, then getting desired moieties of into cells reliably, efficiently, and without generating significant toxicity is of paramount importance.

Current cellular delivery vectors come in many forms and can have many issues: inefficiency, expensive and prohibitively time-consuming to make, difficult to modify or fine-tune, can be quite toxic, or perhaps have other inherent properties which make for potentially problematic assays (e.g. quantum dot “blinking”). Moreover, many cellular uptake experiments are run under complex/harsh conditions specifically in order to effect internalization of whatever moiety is intended to be delivered; that is, many experiments are dependant upon the use of chemical methods (e.g. digitonin), physical manipulation (e.g. microinjection), or even electrical shocks (e.g. electroporation) to allow for materials of interest to enter cells.

The over-arching research interest of the Ryan research group at Iona College is the development of novel tools/platforms with which to potentially identify, probe, manipulate, and/or selectively apoptose cancer cells in vitro and in vivo in an easy and completely customizable fashion. This research is inherently multi-disciplinary; investigating phenomena at the interface of chemistry and biology, using nanotechnology and many engineering disciplines to synthesize innovative molecular structures for ultimate use in a medical setting, and examining biophysical and/or biochemical properties of small molecules using an uncommonly wide range of analytical instrumentation are all accurate descriptions of this research. While our primary interest is focused upon cancer cells, we are continually considering other potential uses for the systems we design, and are generally very open to collaboration with other groups to explore unique approaches, applications, and/or studies.

One such tool currently in development is the exploration of the use of colloidal gold as a potential therapeutic drug-delivery vector. Gold nanoparticles certainly are a strong candidate for such use: the biocompatibility of gold has been well established (in fact, colloidal gold has perhaps the longest history of medicinal use of all metallic sols), gold nanoparticles are simple to make and easily size-tunable, the surface chemistry of gold nanoparticles allow for facile and straight-forward modification with different passivating ligands, many biologically significant moieties have been shown to complex readily and in a stable fashion with gold nanoparticles, and their optical properties - specifically the presence of a strong localized surface plasmon resonance band - make for facile detection schema post-experiment.

It has been previously demonstrated that gold nanoparticles, when complexed with protein conjugates composed of varying amounts of a short nuclear localization signal (“large T,” from Simian Virus 40) bound via organic linker (SMCC) to a large carrier protein (bovine serum albumin), will not only be internalized by human cervical cancer cells (HeLa) merely by placing the nanoparticle complexes in the ambient cell media, but these constructs will localize in the cell nuclei. While many fundamental parameters have been defined for this particular system (pictured above and on the right), our group’s specific intent is to expand, explore, and further refine this system to use gold colloids as a truly multifunctional intracellular delivery vector. For example, a rigorous examination of different types of peptide signals attached via various organic linker molecules to sundry carrier proteins introduced to many types of cell lines are just the beginnings of this project.

Another promising in vitro/in vivo platform to be further developed is the engineering of a highly-ordered protein nanoparticle shell. This protein - ferritin (pictured at right) - is the primary intracellular iron-storage protein in almost all living organisms. 24 monomer units of ferritin naturally self-assemble into a ~12nm nanocage in vivo, separating an interior ~8nm cavity from its exterior solvent. Ordinarily, ambient iron (II) atoms are converted to iron (III) atoms inside these nanocages and stored there until external conditions favor iron release. Briefly, research has begun engineering this system in many distinct and innovative fashions: it is intended to develop methods which combine many unique properties to demonstrate the wide-ranging utility of these ferritin nanocages as small molecule delivery/detection agents in vitro and ultimately in vivo. This protein nanocage presents many exciting possibilities across various scientific disciplines, and our research group looks forward to exploring them thoroughly.