Bioresponsive gels as signal transducers in biosensors

Various hydrogel materials designed to adopt an equilibrium swelling state selectively depending on a biological relevant molecule can be utilized for label-free biosensing. This requires sensitive readout-technology for the monitoring of changes in the hydrogel swelling. We are employing an interferometric readout platform with resolution of 2 nanometer in changes of the optical length within a hydrogel. This set-up allows us to explore biospecific responsive hydrogels as signal transducers for label-free biosensing. The interferometric readout platform is fiber-optic based and the hemispherical 50-60 μm radius hydrogel is covalently attached at the end of the fiber. We have realized a glucose sensing hydrogel material on this platform, where tuning of glucose selectivity is achieved by incorporating a postive charge moiety in addition to the PBA based recognition. We have also realized an oligonucleotide sensing material based on competitive displacement hybridization, which can be designed with a large number of sequence recognition capabilities. Recent applications of the interferometric readout platform include determination of ionic hydrogel response to ionic surfactants and subsequent cyclodextrins, and polymer impregnation. Within the latter topic we have shown that some ionic hydrogels can be transformed to yield a polyampholytic swelling signature by penetrating materials, whereas layering polymers at the surface may constrain the swelling.

References:

• Polyelectrolyte and antipolyelectrolyte effects in swelling of polyampholyte and polyzwitterionic charge balanced and charge offset hydrogels
  Gao, M., Gawel, K. and Stokke, B.T.
  European Polymer J. 53 (2014) 65-74
• Swelling of a hemi-ellipsoidal ionic hydrogel for determination of material properties of deposited thin polymer films: an inverse finite element approach
  Prot, V., Sveinsson, H.M., Gawel, K., Gao, M., Skallerud, B. and Stokke, B.T.
  Soft Matter 9 (2013) 5815-5827
• Cyclodextrin triggered dimensional changes of polysaccharide nanogel integrated hydrogels at nanometer resolution
  Gao, M., Toita, S., Sawada, S.-I., Akiyoshi, K. and Stokke, B.T.
  Soft Matter 9 (2013) 5178-5185
• High resolution interferometry as a tool for characterization of swelling of weakly charged hydrogels subjected to amphiphile and cyclodextrin exposure.
  Gao, M., Gawel K., and Stokke, B.T.
  J Coll Interface Sci 390 (2013) 282-290
• Impregnation of weakly charged anionic microhydrogels with cationic polyelectrolytes and their swelling properties monitored by a high resolution interferometric technique. Transformation from a polyelectrolyte to polyampholyte hydrogel.
  Gawel K., Gao, M., and Stokke, B.T.
  Eur Polym J 48 (2012) 1949-1959
• Logic swelling response of DNA-polymer hybrid hydrogel
  Gawel K. and Stokke, B.T.
  Soft Matter 7 (2011) 4615-4618
• Toehold of dsDNA exchange affects the hydrogel swelling kinetics of a polymer-dsDNA hybrid hydrogel.
  Gao, M., Gawel K., and Stokke, B.T.
  Soft Matter 7 (2011) 1741-1746
• Responsive hydrogels for label-free signal transduction within biosensors.
  Gawel K., Barriet D., Sletmoen M., and Stokke, B.T.
  Sensors 10 (2010) 4381-4409
• Interferometric characterization of swelling of covalently crosslinked alginate gel and changes associated with polymer impregnation.
  Tierney S., Sletmoen, M., Skjåk-Bræk, G. and Stokke, B.T.
  Carbohydrate Polymers 80 (2010) 828-832
• Development of an oligonucleotide functionalized hydrogel integrated on a high resolution interferometric readout platform as a label free macromolecule sensing device.
  Tierney, S., and Stokke, B.T.
  Biomacromolecules 10 (2009) 1619-1626.
• Determination of glucose levels using functionalized hydrogel - optical fiber biosensor: Towards continuous monitoring of blood glucose in vivo.
  Tierney, S., Falch, B.M.H., Hjelme, D.R., and Stokke, B.T.
  Analytical Chemistry 81 (2009) 3630-3636
• Glucose sensors based on a responsive gel incorporated as a Fabry-Perot cavity on a fiber-optic readout platform.
  Tierney, S., Volden, S. and Stokke, B.T.
  Biosensors and Bioelectronics 24 (2009) 2034-2039
• Determination of swelling of responsive gels with nanometer resolution. Fiber-optic based platform for hydrogels as signal transducers.
  Tierney, S., Hjelme, D.R. and Stokke, B.T.
  Analytical Chemistry 80 (2008) 5086-5093.