合成用於偵測細胞內pH值與次氯酸濃度的螢光碳奈米粒子

Abstract

氧化還原及酸鹼反應為影響螢光探針光學性質重要的機制。螢光碳奈米材料由於具有可調控之表面官能基，使其對局部刺激能快速的反應，可作為良好的檢測及顯影工具。於本篇研究中，我們發展一種新型碳奈米粒子 (量子產率 = 10%)，可用於偵測酸鹼值以及次氯酸根離子。此材料設計以間苯二胺為主體提供pH應答性，並結合維生素C多含氧官能基團，改善水溶性及增添氧化還原應答性的功能。因此，此碳奈米粒子可透過螢光變化作為pH探針及 ”turn-off” 探針於中性環境偵測次氯酸。研究結果發現其螢光於酸鹼值5.5至8.5具有線性關係 (R2 = 0.989)，而於中性環境下，對次氯酸根濃度的檢測範圍為0.125–1.25 μM，偵測極限為0.029 μM。此外，我們更進一步將此碳奈米粒子應用於細胞顯影，因具備正電之表面及奈米尺度，賦予其良好的細胞輸送效率，使其成功應用於細胞顯影，並偵測細胞pH值變化及次氯酸。基於以上優異特性，此螢光碳奈米粒子在未來有潛力作為用於細胞偵測酸鹼值及次氯酸根之螢光奈米碳針。

Acid-base and redox reactions are important mechanisms that affect the optical properties of fluorescent probes. Fluorescent carbon nanoparticles which possess tailored surface functionality enable a prompt response to regional stimuli, offering a useful platform for detection, sensing and imaging. In this study, carbon nanoparticle (CNP) was developed as a novel nanoprobe (quantum yield = 10%) for detection of pH and hypochlorite. In the design of CNP, m-phenylenediamine was chosen as the major component of CNP for pH responsiveness, while ascorbic acid which possesses many oxygen-containing groups was incorporated to generate favorable functionalities for improved water solubility and additional response toward redox reactions. Thus, the CNP could serve as a pH probe and a turn-off sensor toward hypochlorite at neutral pH through fluorescence change. The as-prepared CNP exhibited a linear fluorescence response over the pH ranges from pH 5.5 to 8.5 (R2 = 0.989), and over the concentration range of 0.125–1.25 μM for hypochlorite. Meanwhile, the detection limit (LOD) of hypochlorite was calculated to be 0.029 μM at neutral pH. In addition, the CPN was further applied to the cell imaging. The positively charged surface and nanoscale dimension of the CNP caused the efficient cellular delivery of the CNP. The CNP was successfully used to cell imaging and sensitive detection of hypochlorite as well as pH changes in biological system. Given these desirable performances, the as-synthesized fluorescent CNP shows great potential as an optical nanoprobe for cellular sensing of pH values and hypochlorite concentration in the future.