Research Projects

Protein detection is crucial for diagnosing diseases, including cancer. Fluorescence-based techniques have been used for targeted protein detection, but they often face issues like poor solubility, photostability, small Stokes shift, and cytotoxicity. RNA-aptamer-based imaging has gained popularity due to its low cytotoxicity, smaller size, and short development time. Non-cytotoxic Green Fluorescent Protein Chromophore (GFPc) derivatives have been found effective in generating fluorogenic RNA-aptamers, but their photostability is poor due to cis-trans isomerization. Two sets of locked GFPc derivatives have been synthesized by the researchers, which overcome this issue through H-bonding. The molecules have high Stokes shift, absorb between 350-400 nm and emit in the 580-630 nm range, ideal for imaging. However, absorption in near UV regions can be harmful to cells. One set shows a relatively high fluorescence quantum yield (~ 0.15), while the other emits poorly (~ 0.01). The proposed project aims to verify the feasibility of using these two sets of GFPc derivatives as effective targeted protein sensors using selective proteins and RNA-aptamer-based imaging. Understanding the dynamics of probes in different environments, in the absence and presence of protein and RNA-aptamers is essential. A detailed steady state and time-resolved study and imaging in different conditions will provide information on the effect of substituents and ambience on spectra and radiative and non-radiative channels associated with the molecules. This will help design and synthesize improved fluorophores for targeted protein sensing and absorb in the 500-530 nm range, suitable for commercial LASER sources and non-detrimental to cells while still emitting in the orange-red region for RNA-aptamer-based imaging.