Kinetic and thermodynamic insights into interaction of erlotinib with epidermal growth factor receptor: Surface plasmon resonance and molecular docking approaches.

Epidermal growth factor receptor (EGFR) plays an important role in cell proliferation at non-small cell lung cancer (NSCLC). Therefore, targeted therapy of cancer via this kind of receptor is highly interested. Small molecule drugs such as erlotinib and gefitinib inhibit EGFR tyrosine kinase and thus suppress cell proliferation. At this paper, erlotinib interaction with EGFR on the cell surface was studied via surface plasmon resonance (SPR) and molecular docking methods. Kinetic parameters indicated that erlotinib affinity toward EGFR was increased through increment of temperature. The thermodynamic analysis showed that van der Waals and hydrogen binding forces play a major role in the interaction of erlotinib with EGFR. Docking results showed that Domain II in EGFR has role in the interaction with erlotinib. Besides, the binding energy for this interaction was -10.7 kcal/mol, which is suitable for binding of erlotinib to Domain II in EGFR.

Nanomaterials and phase sensitive based signal enhancment in surface plasmon resonance.

Measurement of small molecules in extremely dilute concentrations of analyte play an important role in different issues ranging from food industry to biological, pharmaceutical and therapeutical applications. Surface plasmon resonance (SPR) sensors can be a suitable choice for detection of small molecules based on interactions with biomolecules. However, sensitivity of the system for detection of these molecules is very low. Improving sensitivity has been a challenge for years. Therefore, different methods have been used to enhance SPR signals. The SPR signal enhancement using numerous nanomaterials has provided exciting results. Among various nanomaterials, metal nanoparticles (for instance gold, silver and magnetic nanoparticles), quantum dots, nanorads, and carbon-based nanostructures have got much attention due to ease in fabrication, appropriate size and shape. In addition to the advantages provided by using nanomaterials, signal enhancement provided by the appropriate use of phase information of the reflected light could be also important to improve SPR sensitivity. Phase-sensitive SPR sensors are able to detect infinitesimal changes in external properties of target while traditional type of SPR cannot demonstrate these changes. This article provides an overview on signal enhancment in SPR using nanomaterials and properties of light. We also discuss on recent progresses of the field, describing basic concepts concerning nanostructures as well as phase-sensitive sensors as platform for enhancement of signal in SPR.