An Update of DNA Hydrogel Application in Biosensing

DNA gel not only uses the skeleton function of hydrogel but also the biological function of DNA to realize the unified fusion of the structure and function of hydrogel material. By introducing specific small molecules into the DNA gel, it can respond to pH, temperature, ultraviolet, infrared, metal ions, and drug small molecules. To further realize the detection and loading of various small molecules in the biomedical field, the specific recognition and detection of heavy metal ions and toxins in the environment are done. In this paper, the preparation of pure DNA gel and hybrid DNA gel, their detection in the biomedical and environmental fields are reviewed, and their prospects and further development directions are discussed.     

Mechanical Enhancement of the Strain-Sensor Response in Dimers of Strongly Coupled Plasmonic Nanoparticles

Due to their particular optical and mechanical properties, plasmomechanical devices have become choice candidates in strain sensing applications. Using numerical simulation, a plasmomechanical system consisting of two gold nanoparticles with different shapes and separated by a small gap, deposited onto a deformable polydimethylsiloxane membrane, is investigated. With the aim of understanding the relationship between the plasmonic behavior of gold nanoparticles and induced mechanical deformations, mechanical extension ranging from 0% to 20% is applied to the polydimethylsiloxane membrane. In a first step, a mechanical calculation based on a hyperelastic model for polydimethylsiloxane shows that the interparticle spacing is enhanced nonlinearly by a percentage greater than the externally applied deformation, depending on the shape and size of the nanoparticles as well as the polydimethylsiloxane membrane thickness. Full optical simulation of the deformed nanosystems demonstrates that the plasmonic resonance wavelength is highly sensitive to the applied displacements and is enhanced compared to a basic approach where the gap deformation is taken as equal to the macroscopic applied deformation. The best figure of merit ($0.022{\%}^{-1}$) is obtained for the disk–rod dimer near the strong coupling regime, larger than the values reported in the literature for localized nanoparticle systems.