Typical medical imaging techniques can usually only alert of the presence or absence of abnormal growths. These techniques must then be followed by biopsies to obtain more information about the molecular properties of the tissue in consideration. Imaging techniques that provide both structural and molecularly relevant information are greatly needed. In our group, we aim to develop agents that can provide disease-specific contrast. Such contrast agents are designed to indicate the location of the abnormal tissue mass, while also providing information about its molecular characteristics such as localized overexpression of certain growth factors. This information, in turn, can aid in diagnosis, prognosis, and monitoring of patients. One of the current projects focuses on the development of cancer-targeted near infrared fluorescent nanoparticles for optical imaging.
Most nanoparticle-based drug delivery systems developed to date are not designed for disease-triggered release of active compounds. In fact, their function is founded mostly on diffusion of drug molecules from bulk polymeric nano-constructs. In recent years, there has been great urge for the development of drug delivery systems that can deliver drugs on demand. These systems are designed for drug release upon detection certain pathological conditions such as decreased pH. These systems, while innovative, are suboptimal in some applications due to the low specificity of the trigger mechanism. The aim of our research is to develop responsive nanostructures that can be activated by disease-specific molecules. The vision is to engineer nanostructures in such a way that recognition of specific molecular targets will lead to on-demand drug release. Hybridized nucleic acid linkers, enzymatically cleavable linkers, polyelectrolytes, and amphiphilic copolymers are being utilized to offer disease-specific response.
The techniques utilized for disease-specific drug delivery and imaging contrast are also leveraged for the development of biosensors. Specifically of interest are nucleic acid probe based systems that can produce on-demand fluorescence in the presence of the target molecule. Incorporation of these probes within multifunctional nanoparticles provides opportunities for disease targeting, high payload, and dual detection/therapy.