Optical Reporting by Conjugated Polymers via Conformational Changes - Advanced Fluorescence Reporters in Chemistry and Biology - page 406

found that the polymer could not only act to induce a conformational change but
also to directly report that change in the proteins structure.

5.2 Protein Aggregates

Nilsson and coworkers went on to use the anionic polymer (PTAA) for detection of
amyloid fibril formation of bovine insulin [ 29 ]. The aggregation of proteins into
fibrillar assemblies is problematic in diseases such as Alzheimer's, spongiform
encephalitis, Parkinson's, Huntington's, and even in such practical applications
as pharmaceutical insulin storage and delivery in the treatment of diabetes. As the
monomeric proteins denature or change from their determined native states, they
aggregate and form a repeating b sheet structure that further extends to form fibrils
verifiable by transmission electron microscopy (TEM) (Fig. 15 ), CD spectroscopy,
and historically with the characteristic gold-green birefringence from congo red
dye [ 30 ].
Use of the anionic CP allowed for detection of amyloid fibril formation in both
bovine insulin and chicken lysozyme proteins (Fig. 16 ). The polymer in buffer

Fig. 15 Schematic drawing of the formation of amyloid fibrils. (a) Monomeric insulin having an
a -helical conformation. (b) b -sheet ( arrows ) rich oligomers are being formed. (c) Amyloid fibrils
having a diameter around 10 nm are being formed. (d) Higher magnification of the intrinsic
repetitive -pleated sheet structure of the amyloid fibril. The pictures were taken by transmission

electron microscopy (TEM)

b