International Journal of Nanomedicine (Sep 2020)
Amino-Functionalized Nitrogen-Doped Graphene Quantum Dots for Efficient Enhancement of Two-Photon-Excitation Photodynamic Therapy: Functionalized Nitrogen as a Bactericidal and Contrast Agent
Abstract
Wen-Shuo Kuo,1,2,* Tien-Sung Yeh,3,* Chia-Yuan Chang,4 Jui-Chang Liu,2 Chang-Hsin Chen,5 Edmund Cheung So,6,7 Ping-Ching Wu8 1School of Chemistry and Materials Science, Nanjing University of Information Science and Technology, Nanjing 210044, Jiangsu, People’s Republic of China; 2Allergy & Clinical Immunology Research Center, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan, Republic of China; 3Department of Physical Medicine and Rehabilitation, An Nan Hospital, China Medical University, Tainan 709, Taiwan, Republic of China; 4Department of Mechanical Engineering, National Cheng Kung University, Tainan 701, Taiwan, Republic of China; 5AbVision Inc., Milpitas, CA 95035, USA; 6Department of Anesthesia & Medicine Research, An Nan Hospital, China Medical University, Tainan 709, Taiwan, Republic of China; 7Graduate Institute of Medical Sciences, Chang Jung Christian University, Tainan 711, Taiwan, Republic of China; 8Department of Biomedical Engineering, National Cheng Kung University, Tainan, 701, Taiwan, Republic of China*These authors contributed equally to this workCorrespondence: Edmund Cheung So; Ping-Ching Wu Email [email protected]; [email protected]: Although graphene quantum dots (GQDs) have received considerable research attention for their applications in various fields, the use of GQDs, such as nitrogen-doped GQDs (N-GQDs) and amino-functionalized N-GQDs (amino-N-GQDs), as photosensitizers to facilitate photodynamic therapy (PDT) has received limited research intention. To address this research gap, this study prepared novel amino-N-GQDs and investigated their properties.Methods: The amino-N-GQDs subjected to two-photon excitation (TPE) exhibited remarkable bactericidal capability in PDT. The bonding compositions of nitrogen and the amino-functionalized group played a critical role in their antimicrobial effects.Results: Compared with amino-group-free N-GQDs and amino-N-free GQDs, the amino-N-GQDs generated a higher amount of reactive oxygen species, demonstrating their superior efficacy for two-photon PDT. Additionally, the intrinsic luminescence properties and high photostability of the amino-N-GQDs demonstrate their suitability as an effective two-photon contrast agent for tracking bacteria during two-photon biomedical imaging.Conclusion: The amino-N-GQD and their remarkable properties may provide an efficient alternative approach for observing and easily eliminating malignant microbes in the future.Keywords: nitrogen atom-doped graphene quantum dots, amino-functionalized and nitrogen atom-doped graphene quantum dots, two-photon photodynamic therapy, two-photon contrast agent, two-photon biomedical imaging