Developing Novel Fluorescent Thermo- or Hydrogen Peroxide-Responsive Nanoprobes with Ratiometric Readout and Exploring their Potential in Biomedical Applications
Date Issued
2014
Date
2014
Author(s)
Chen, Chun-Yen
Abstract
The studies of this thesis are divided into two parts:
Section I describes that a novel nanothermometer Thermo-3HF with self-calibrating ratiometric fluorescence readout was designed and synthesized by taking advantage of the fluorescence nature of 3-hydroxyflavones. Thermo-3HF consists of thermoresponive NIPAM unit, crosslinker MBAM unit, and environmentally-sensitive 3-HFAM fluorescent unit in a ratio of 100: 1: 1. Within a sensing temperature range of 33 to 41 oC, the fluorescence color of the Thermo-3HF nanothermometer changes from blue to green. The ratiometric change magnitude is about 8.7-fold, rendering the visual differentiation of color by the naked eyes feasible.
Section II describes the early-stage result of developing multifunctional drug delivery nanovectors. A reaction-based cross-linked polymeric nanoprobe HP-3HF with self-calibrating ratiometric fluorescence readout to selectively detect H2O2 is reported. HP-3HF nanoprobe is fabricated by hydrophobic H2O2-reactive boronic ester groups DCBE, crosslinker units HQBAE, and environmental-sensitive 3-HFAM fluorophores via miniemulsion polymerization. Upon the treatment of H2O2, the boronic esters in the polymer are cleavaged to form hydrophilic alcohols, subsequently leading to a hydrophobic/hydrophilic transition. Covalently linked 3-hydroxyflavones manifest the change in polarity as a ratiometric transition from green to blue, accompanied by a 500-fold increase in its volume. In addition, HP-3HF nanoprobe has been exploited for ratiometric glucose sensing by monitoring the H2O2 generated from the oxidation of glucose via glucose oxidase, and thus successfully distinguished between normal and pathological levels of glucose. After completing these tests, the potential of HP-3HF as a H2O2-responsive drug delivery nanovector for the remedy of cancers or inflammation-related diseases has been explored. The assessments of cellular uptake and cytotoxicity analysis of HP-3HF nanovector in RAW 264.7 macrophages confirm that HP-3HF is biocompatible and easy to enter into cells. The drug-releasing experiment of Nile Red-encapsulated HP-3HF (NR@HP-3HF) upon H2O2 stimulation also shows that HP-3HF is feasible as a controlled drug delivery nanovector.
Subjects
應答型聚合物
螢光比例輸出
溫度
過氧化氫
藥物輸送系統
SDGs
Type
thesis
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