Mechanically Modulating the Photophysical Properties of Fluorescent Protein Biocomposites for Ratio‐ and Intensiometric Sensors

Abstract

Mechanically sensitive biocomposites comprised of fluorescent proteins report stress through distinct pathways. Whereas a composite containing an enhanced yellow fluorescent protein (eYFP) exhibited hypsochromic shifts in its fluorescence emission maxima following compression, a composite containing a modified green fluorescent protein (GFPuv) exhibited fluorescence quenching under the action of mechanical force. These ratio- and intensiometric sensors demonstrate that insights garnered from disparate fields (that is, polymer mechanochemistry and biophysics) can be harnessed to guide the rational design of new classes of biomechanophore-containing materials.

Kinetic Analysis of Mechanochemical Chain Scission of Linear Poly(phthalaldehyde)

“…Polymer architectures have the ability to channel elongational forces to the chain midpoint where bond scission occurs if the forces are great enough. [ 1,2 ] In most cases, two half-chain polymer fragments are generated, and these newly formed chain ends are capable of subsequent reaction. [ 1 ] It was recently demonstrated that ultrasound-induced cavitation could be used to mechanochemically trigger the depolymerization of a low-ceiling temperature ( T c ) polymer.…”

Mechanochemical Sensing: A Biomimetic Sensing Strategy

“…In addition, changes in fluorescent properties of protein biocomposites caused by mechanical stress have been reported. [17] Mechanical force is au niversal variable that can be used to describe both microscopic andm acroscopic processes such as electron-nucleus interactions, breaking or formationo fc hemical bonds, as well as various functions of tissues, organs,a nd engineering materials.O ther than the covalentb onds in polymers, in which nanonewton forces are involved for the breaking of covalentb onds, [18] extensive efforts have been spent on investigating mechanochemicalp rocesses in noncovalent bonds. For example, piconewton forces have been shown to fold or unfold proteins, DNA, and RNA molecules.…”

Approaches to polymeric mechanochromic materials

“…Schaaf, Schiller, and coworkers covalently grafted genetically modified green fluorescent proteins onto a poly(dimethyl siloxane) surface and showed that uniaxial mechanical stresses resulted in a fully reversible linear decrease of the fluorescence intensity that was attributed to conformational changes of the protein . Moreover, fluorescent proteins were also employed in polymer matrices and their fluorescence signal was used to facilitate the detection of compressive stresses . These mechanochromic materials rely on the unfolding of complex proteins to induce a color change and demonstrate how a chromic response can be achieved on the basis of noncovalent interactions.…”