用於生物成像與次毫米發光二極體之 近紅外一/二區奈米粒子

Abstract

近年來，近紅外光(near-infrared; NIR)區域備受矚目，因其高穿透深度、低散射、低生物自體螢光等優勢，於光學成像領域樹立一里程碑。針對高解析度影像進行深入之可視化與研究，此將有助於準確診斷與治療疾病。經螢光粉轉化近紅外光可進而應用於次毫米發光二極體(mini light-emitting diode; mini-LED)。若此近紅外光螢光材料經適當之表面修飾，則可應用於生物醫學領域之生物成像與治療。本研究闡明NIR-I/II區於生物成像與mini-LED中之相互依存性與其重要性。 近紅外光二區(second near-infrared; NIR-II)之波段具高穿透深度多用於生物影像，本研究以中孔洞二氧化矽奈米粒子作為一高生物相容性之模板，其可裝載尖晶石ZnGa2O4，並經不同濃度之Cr3+與Ni2+進行共掺雜，藉能量轉移之形式將能量由Cr3+轉移至Ni2+，獲得1285 nm之最高放光強度與5 mm深度之小鼠體內成像。 為提高影像之空間解析度，現今多以稀土元素材料作為奈米探針開發NIR-IIb區域(1500–1700 nm)，因其具豐富能階，可產生多種紅外線發射。本研究乃以氧化釓(Gd2O3)作為主體晶格材料，藉掺雜Yb3+ 與Er3+於808 nm激發下可獲得1530 nm之放光與41%之量子效率。此外，系統中之Gd具磁效應，不僅可提供核磁共振影像(magnetic resonance imaging; MRI)，Yb與Er則可提供NIR-IIb影像，達雙重生物顯影，以改善生物影像之解析度，使此系統成為生物醫學研究之理想選擇。 除生物影像與治療外，奈米螢光材料於mini-LED之應用亦具發展潛力。本研究亦研究將反尖晶石結構之MgGa2O4掺雜Cr3+ 與Ni2+過渡元素之系統嵌入中孔洞二氧化矽奈米粒子中，藉此將材料尺寸縮小至奈米尺度。因Cr3+−Ni2+具能量轉移，於1270 nm處具79.2%之優異量子效率，並成功封裝於mini-LED，使奈米螢光材料於LED產業中具實際應用價值。

The near-infrared (NIR) region has garnered much interest in recent years. Multifarious advantages of high penetration depth, lower scattering, and autofluorescence have created a trademark for this region in the optical imaging domain. In-depth visualization and study of physiological changes in higher resolution can help in the accurate diagnosis and treatment of diseases. NIR light can be emitted by phosphors by the fluorescence process, which, in turn, can be utilized in mini-light emitting diodes (mini-LEDs). If appropriately functionalized and coated, they can be used in biomedical avenues of bioimaging and therapy. In this doctoral thesis, the interdependence of the NIR-I and NIR-II regions in bioimaging and mini-LED is promoted, evoking the importance of this region. The high penetration depth of the second near-infrared region (NIR-II) was used for bioimaging. To create a biocompatible template, mesoporous silica nanoparticles were fabricated and integrated by the spinel ZnGa2O4 system, followed by doping with different concentrations of Cr3+ and Ni2+ to procure the highest emission intensity at 1285 nm via energy transfer mechanism from Cr3+ to Ni2+. As the nanophosphor field has yet to be explored to a great length, this material was developed and used to obtain in vivo images at a significant depth of 5 mm for brain vessel imaging. The NIR-IIb region (1500–1700 nm) was investigated to improve the images’ spatiotemporal resolution. Lanthanides as nanoprobes are bestowed with generous energy levels, enabling several emissions. Oxide host (Gd2O3) was engaged in the lanthanide study due to their easier fabrication and wide band gap, doped with Yb3+ and Er3+, offering a high (percentage %) quantum yield of 41.1% and emission at 1530 nm. Moreover, Gd3+ possesses magnetic properties, which validate this lanthanide system for magnetic resonance imaging (MRI). The dual-modal imaging of NIR-IIb fluorescence and MRI imaging improve the images’ clarity with utmost precision and make this lanthanide system a great candidate for biomedical diagnosis. In addition to the field of bioimaging and therapy, nanophosphor materials have the potential to be packaged in mini-LEDs to enhance the convenience of the system. Incorporating the inverse spinel structure of MgGa2O4 doped with Cr3+ and Ni2+ transition elements, this system is embedded in mesoporous silica nanoparticles to reduce the size to nanoscale. The nanophosphor showed emission at 1270 nm with an excellent quantum yield of 79.2% due to energy transfer from Cr3+ to Ni2+. The mini-LED package revealed emission in the NIR-II region, qualifying this nanophosphor for pragmatic applications in the LED industry.