Artem Yakovliev,Tymish Y. Ohulchanskyy,Roman Ziniuk,Tereza Dias,Xin Wang,Hao Xu,Guanying Chen,Junle Qu,Anderson S. L. Gomes
In this work, the application of near infrared (NIR)-emitting NaYbF 4 :1%Tm 3+ @NaLuF 4 :30%Nd 3+ core–shell nanoparticles is reported for noninvasive probing and monitoring the temperature during photopolymerization of dental materials. When excited at 808 nm, the synthesized nanoparticles emit NIR photoluminescence (PL) with two distinctive peaks at 865 and 980 nm which correspond to radiative transitions from the doped Nd 3+ and Yb 3+ ions, respectively. Luminescence intensity ratio between these two bands is found to vary with temperature due to temperature-dependent electronic excitation energy transfer between Nd 3+ and Yb 3+ ions at the core/shell interface. This finding allows luminescence ratiometric evaluation of the in situ temperature during photopolymerization of resin cement (doped with nanoparticles) in a veneer placement procedure. In addition, the NIR emission also enables PL imaging of the distribution of the adhesive under the veneer. The results highlight that rare-earth ions–doped nanoparticles with both excitation and emission in the NIR spectral range are advantageous for both PL-based nanothermometry and imaging due to the reduced attenuation of NIR light by dental ceramics.
Yanxia Zheng,Gang Dong,Liyong He,Gang Wu,Huade Zheng,Chunlin Deng
Calcium phosphate layers, which are widely applied on the surface of biomaterials, are important for improving tissue regeneration performance. The composition of layers formed on the surface of biomaterials differs depending on the soaking fluid. Herein, revised simulated blood fluid and fast calcification solution were investigated as immersing solutions for the mineralization of hydroxyapatite ceramics. The morphology of the hydroxyapatite particles and precipitate formation on the hydroxyapatite ceramics surface were characterized by transmission electron microscopy . Furthermore, scanning electron microscopy was used to examine the morphology of the bioactive ceramics surface. The structure of the layers was determined by selected-area electron diffraction. The prepared hydroxyapatite powders were characterized by powder X-ray diffraction. The results showed that hydroxyapatite was preferentially formed on the hydroxyapatite ceramics surface in revised simulated blood fluid and octacalcium phosphate precipitated in fast calcification solution. Additionally, the content of HCO 3 - in the mineralization fluid strongly influenced the crystal phase composition and morphology of the calcium phosphate layers on the bio-ceramics materials studied herein.
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