本研究使用微波輔助加熱合成法合成的銅氮摻雜碳點(Cu,N@CDs)，利用其螢光(PLQY= 74%)以及低毒性等特性，作為生物顯影劑和藥物載體結合兩種抗癌藥物喜樹鹼(Camptothecin, CPT)以及替拉札名(Tirapazamine, TPZ)。將Thiol linker (TL)與CPT結合形成TLCPT，利用TL的羧酸根用EDC/NHS法與碳點結合，藉由碳點豐富的芳香結構與TPZ以π-π interaction之方式形成弱氫鍵，接下來將Hydrogenated lecithin (HL)與Cholesterol、Polyoxyethylene-40 stearate (SPEG-40)混和形成HCP733，將HCP733與結合兩種藥物之碳點混和以超聲波分散法形成具有雙層磷脂質結構的脂質體(LCuCCT)。
LCuCCT的雙層磷脂質結構與細胞膜的結構相似能增加材料細胞內化的程度。由於癌細胞代謝產生過量的乳酸以及氫離子，使腫瘤細胞處在較低之酸鹼值(pH=5.5)。脂質體HL的部分在酸性環境會質子化並且變得不穩定，會於細胞內釋放結合藥物的碳點，碳點上的銅離子不只能夠消耗癌細胞內用來平衡自由基的穀胱甘肽(GSH)，還能進行化學動力療法（CDT）產生自由基。除了CDT的療效外，產生的自由基還能夠破壞TL上的雙硫鍵，從而釋放出抗癌藥物CPT。酸性條件還能使碳點與TPZ間的弱氫鍵變得不穩定進而釋放藥物。此外，脂質體還有維持藥物活性以及防止碳點螢光焠滅的特性，進一步延長LCuCCT的療效於人體的穩定性。
通過細胞實驗，證實本研究所使用的材料具有高生物相容性。多藥物和化學動力療法的協同治療導致大量的晚期細胞凋亡，並且在細胞螢光顯影實驗中也得到相同的結果。表明了LCuCCT能夠被細胞攝取，並且具有產生自由基、藥物釋放等治療癌症的功效。

In this study, copper-nitrogen-doped carbon dots (Cu,N@CDs) were synthesized using the microwave-assisted heating synthesis method. These dots were employed as a biological imaging agent and drug carrier by leveraging their fluorescence (PLQY = 74%) and low toxicity. To create the drug carrier, a Thiol linker (TL) was combined with Camptothecin (CPT) to form TLCPT. The carboxylate of TL was then used to bind with carbon dots via the EDC/NHS method. Weak hydrogen bonds were formed between TLCPT and Tirapazamine (TPZ) through π-π interactions with the rich aromatic structure of carbon dots. Next, Hydrogenated lecithin (HL) was mixed with Cholesterol and Polyoxyethylene-40 stearate (SPEG-40) to create HCP733. HCP733 was then mixed with carbon dots combined with CPT and TPZ to form liposomes with a bilayer phospholipid structure (LCuCCT) using ultrasonic dispersion. The bilayer phospholipid structure of LCuCCT resembled the cell membrane, enhancing internalization by the target cells.
The acidic environment of tumor cells (pH=5.5) due to the excess lactic acid and hydrogen ions resulting from their metabolism plays a critical role in the drug release mechanism. In this acidic environment, liposome HL becomes protonated and unstable, leading to the release of drug-bound carbon dots inside the cells. The copper ions on the carbon dots serve a dual function: consuming glutathione (GSH) in cancer cells to balance free radicals and generating free radicals through chemodynamic therapy (CDT). Additionally, the free radicals generated break down the disulfide bond on TL, releasing the anticancer drug CPT. The acidic conditions also destabilize the weak hydrogen bonds between carbon dots and TPZ, thereby releasing the drug.
Furthermore, liposomes maintain drug activity and prevent carbon dot fluorescence quenching, thus extending the curative effect of LCuCCT and ensuring its stability in the biological environment. Cell experiments have demonstrated the high biocompatibility of the materials used in this study. The synergistic treatment of multidrug and chemodynamic therapy resulted in a significant increase in late apoptosis, as confirmed by PI-Annexin flow cytometry experiments. The results indicate that LCuCCT can be effectively taken up by cells and has the ability to generate free radicals and release drugs to treat cancer cells. As a result, the designed LCuCCT exhibited outstanding therapeutic benefits for image-guided cancer therapy.

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