| The development of medical technology has been greatly improved， however， there are still alot of diseases cannot be solved, such as HIV, cancers, genetic diseases, and other new virus.Recently, the development of biomedical technology is fast. And as the fundamentals for this field,bio-sensing technology has absorbed tremendous attention.The water-soluble conjugated polymers, namely, the conjugated polymeric electrolytes (CPEs),which characterized with signal amplification induced due to their conjugated main chains, andgood water solubility, is widely used in biosensing technology. It is known that the mechanisms ofbio-sensing method usingconjugated polymers are roughly devided into three classes as: electrontransfer (ET), fluorescence resonance energy transfer (FRET) and the analyte-induced aggregationor conformation changes.Among these mechanisms, sensing method based on analyte-induced aggregation has rarelybeen investigated. Most of the bio-sensing systems working under the ET or FRET mechanismsusing the CPEs need labeling the biomolecularpre-forward, which are always very complex,expensive, and are unfavorable for their commercial applications.Accordingly, this thesis investigated a CPE-based bio-sensoring platform with a structure of acationic polyfluorenes containing2,1,3–benzothiadiazole (BT) units (P4) and the mechanism ofan analyte-induced aggregation. Then we studied the optical properties and application of P4inlabel-free detection of biological macromolecules, covering anionic surfactant, DNAs and Proteins.The whole work mainly are divided into four parts as follows:First, P4was designed and synthesized successfully.Second, theinteraction between P4and the negatively charged sodium dodecyl sulfate (SDS)has been studied, anda reasonable model of three transition states has been given.Third, the application of P4in the detection of biological macromolecules has been studiedcarefully. The qualitative and quantitative detection of single-stranded DNA can be realized with P4as a label-free probe and the adding of complementary DNA single strand chain. The preliminaryscreening of cancer marker protein, which is of great significance for early cancer diagnosis, can beachieved using P4. Combined with adenosine triphosphate (ATP), P4can also be used in detectingof alkaline phosphatase (ALP).Forth, the interaction between P4, gold nanoparticles or sulfhydryl wrapped gold nanoparticles and DNA in one solution has been researched with a pre-addition or a post-addition fashion. |
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