Manipulating conformation of individual biomolecules

Biological systems in nature possess interesting complex functions that would offer solutions to many material science applications such as biosensors and bioactuators, but are inherently difficult to control. Meanwhile, non-biological systems are relatively easy to control, but applicability is limited. The goal is to combine the biological and non-biological domains so that one can influence conformation of the studied biomolecule and hence the functionality of the biomolecule. To achieve this, one can utilize e.g. pH and electric and magnetic field to elongate, shrink, bent and twist the biomolecules, which are typically immobilized on a substrate.

The first biomolecule we have tested for the method is a DNA-hairpin, which consist of two ssDNA arms and a loop, where the objective is to open and close loop of the hairpin in controllable fashion, by help of a charged gold nanoparticle (AuNP) attached to a one arm of the DNA-hairpin. Distance, which is related to the conformation of the hairpin, can be tracked by measuring the localized surface plasmon resonance (LSPR) of AuNP, which depends on the distance between the AuNP and the Au-surface. This scheme can be implemented to study other biomolecules also.