Synthesis and optical studies of upconverting fluorescent nanomaterials

尽管在过去的一个世纪中取得了许多进步，但除非促进重大的科学和技术突破，否则社会将在生物医学，法医和安全（指纹检测，爆炸物标签和防伪造文件）方面面临严峻的挑战。这些挑战可能受益于纳米技术，包括确定许多疾病的分子起源和早期检测，这两者对于有效治疗至关重要。许多挑战将取决于对原子和分子集合体的性质和行为的理解，这些性质与更大尺度上的性质有很大不同，以及新纳米材料的合成。我们研究项目的首要目标是合成镧系元素掺杂的上转换纳米粒子，并表征它们的光物理、结构和化学性质。上转换荧光粉被红外辐射（低能量）直接激发，导致可见光或紫外线发射（高能量）。使用红外线辐射是有利的，因为它对细胞的危害较小，穿透组织的程度更大，几乎消除了自身荧光。因此，使这些材料成为生物成像的理想材料。这些掺杂镧系元素的纳米材料也可能是多模态活动的理想平台，如光学成像、治疗和MRI。这是可能的，因为这些材料可以掺杂不同的镧系离子。

Despite the many advances which have occurred over the past century, society will be faced with daunting challenges in biomedicine, forensic and security (fingerprint detection, tagging of explosives and anti forgery of documents) unless major scientific and technological breakthroughs are fostered. These challenges, may benefit from nanotechnology, including identifying the molecular origins of many disease and early detection, both of which are paramount to effective treatment. Many of the challenges will depend on understanding the properties and behavior of aggregate of atoms and molecules at a scale where properties differ significantly from those at the larger scale and on the synthesis of new nanomaterials. The overriding objective of our research program is the synthesis of lanthanide doped upconverting nanoparticles and to characterize their photophysical, structural and chemical properties. An upconverting phosphor is excited by infra red radiation(low energy) directly, leading to visible or UV emission(high energy). The use of infra red radiation is advantageous since it is less harmful to cells, penetrates tissue to a greater extent and virtually eliminates autofluorescence. Thus, making these materials ideal for bioimaging. These lanthanide doped nanomaterials may also be an ideal platform for multi modal activities such as optical imaging, therapeutics and MRI. This is possible since these materials may be doped with different lanthanide ions.