Fabrication Of Nanomaterials Based FRET Sensor And Its Application For Detection Of Tumor Markers

Fluorescence resonance energy transfer (FRET) is an analytical method of spectroscopy, which is based on non-radioactive energy transfer between fluorescent materials. FRET has been widely used in various fields of agriculture, pharmaceutical, forensic, and scientific research. Since the theory was first proposed, FRET technology had got greatly improvements in both the spatial resolution and sensitivity aspect. And FRET sensor has wide applications in the field of biological research, such as conformational changes of biological macromolecules, interactions between biological macromolecules, nanoscale measurements of the distance between biomolecules and so on. Recent studies show that both the optical properties of energy donor/acceptor and assembling methods for FRET sensor have a crucial impact on the performance of FRET sensor. However due to the low fluorescence intensity, poor light stability, environmental sensitive for biological materials, and rare species for lanthanides of the tradition energy donors and receptors (such as organic dyes, biological materials, lanthanides, etc), the development and application of FRET sensor have been limited greatly. Nanomaterials are materials with size in nanoscale range (1-100nm) that at least one dimension or constituted by nanoscale materials as the basic units. Special structure of the nanomaterials makes them very different from the common materials in the nature of optical, electrical, magnetic, and other aspects. The emergence and continuous development of nanomaterials provide new opportunities for the development of FRET sensors. Nanomaterials based FRET sensors have been constantly developed for biology research field because of their superior detection performance. Therefore, investigations of FRET sensors based on nanomaterials have significance in both theoretical studies and practical applications. Herein, based on the available research of FRET sensor for MMP-2, we choose different energy donor/receptor and different assembling methods to prepare new excellent probe to achieve the sensitive detection of MMP-2. The main research studies as follows: (1) Graphene oxide was prepared by the Hummers method, and then carboxyl groups were enriched its surface through carboxyl processing, which serves as an energy acceptor. Energy donor fluorescein isothiocyanate (FITC) and energy receptor graphene oxide were linked with the peptide which was specially recognized by MMP-2through the covalent reaction between amino and carboxyl to construct FRET sensor. Finally, the FRET sensor was used for the detection of MMP-2. The results showed that GO based FRET sensor for MMP-2had a good detection performance. The linear range was from10to150ng/mL with linear equationâ–³F=2.57c (ng/mL)+10.84(regression coefficient r=0.9951). The limit of detection was2.5ng/mL (3S/N).(2) We prepared an amphiphilic molecule with azide group, using poly(acrylic acid) as basic skeleton. And this amphiphilic molecule was used to modify gold nanoparticles and quantum dots, making them transfer from oil phase into aqueous and get azide group on their surface. Then, based on the peptide sequence which MMP-2could specifically recognize, we got a peptide with different alkynyl at its end. Finally, we constituted a FRET sensor based on click chemistry reaction, using the obtained quantum dots as donor, gold nanoparticles as receptor and the peptide as bridge, and this sensor was used to detect MMP-2.