Gold Nanoparticles Based Surface-Enhanced Raman Scattering(SERS) Imaging In Biomedical Applications

Surface-enhanced Raman scattering(SERS)imaging technology,as a fast,efficient,non-destructive and highly sensitive emergent imaging method,has gradually emerged in the field of medical.In this thesis,the most commonly used gold nanoparticles and nearinfrared dye DTTC are selected as SERS-enhanced substrates and Raman signal molecules,respectively.Based on SERS imaging technology,its applications in different aspects such as multimodal tumor imaging,integration of tumor diagnosis and treatment,stem cell labeling and tracing are studied.(1)A nano-theranostic system(HAu NP@DTTC)constructed by hollow gold nanoparticles(HAu NP)and DTTC,which has SERS imaging and photothermal therapy(PTT)performance.The delivery efficiency of HAu NP@DTTC to tumors and their enrichment in tumors are improved by the pre-irradiation(Pre-IR)treatment of X-ray.Through a systematic review of the constructed nano-theranostic system(HAu NP@DTTC),proved that the tumor can be diagnosied accurately by the use of SERS imaging,the mice with the addition of X-ray treatment show better tumor suppression effect.(2)In order to improve the uneven heat distribution of PTT for tumor,we combine image-guided surgical resection with PTT for the treatment of tumor.Combined SERS image guided tumor surgical resection with PTT for the residual microcarcinoma,which improve the prognosis of the tumor.A diagnostic agent(Au-Ur@DTTC NPs)is constructed by the use of urchin-like gold nanoparticles(Au-Ur NPs),which have stable and sensitive SERS signals.Firstly,its ability for accurate diagnose of two kinds of abdominal tumors(CT26 and SKOV3)is studied by SERS imaging technology.Then the tumor is resected under SERS images,and PTT is performed for the remaining tumors that can not be resected already.The results demonstrate that,the SERS imaging can find the boundaries of the tumors successfully and provide a basis and reference for precise surgical resection,by the combining of PTT treatment after surgery,the tumor recurrence after surgery is improved.Compared with the blank control group,the tumor recurrence rate is reduced to 25%,and the survival cycle of mice is prolonged(> 36 days).(3)In view of the extremely high sensitivity and good biological safety of SERS imaging technology,we pioneered the application of SERS imaging to the labeling and tracing of mesenchymal stem cell(MSC).The effects of the labeling on MSC behavior are investigated,the results show that the MSC can be labeled by the Au-Star@DTTC NPs successfully and realized SERS imaging of MSC,and the labeling has no effect on the proliferation and migration capabilities of MSC.At the same time,the tracking sensitivity and period for the labeled MSC are investigated at the animal level.Moreover,the damage models are used to investigate the ability of MSCs for tissue repairing.The repair process is monitored by SERS imaging,the results show that the labeled MSCs can be detected even when the MSCs number is as few as 200,and verifies that the tissue repair process with MSCs can be monitored up to 45 days.