Baojin Ma1 Hong Liu1

1, Shandong University, Jinan, , China

Hydroxyapatite (HAp) is major constitute of bone and approved by FDA. Due to high biocompatibility and good biodegradability, HAp has been applied in various biofield. One-dimension (1D) HAp nanostructures possess unique advantages, such as high specific surface area, easy degradability, good plasticity and so on, and have been widely investigated.

Nanorods can be synthesized simply and have great potential in drug delivery and scaffold preparation. For drug delivery and sustained release visualization, endowed HAp fluorescence becomes a feasible method. By terbium/europium codoping, fluorescent HAp nanorods with dual color emission under 488 nm excitation was prepared, and can image cells efficiently. Further, CQD-HAp hybrid nanorods were prepared by self-assembling CQDs on the surface of HAp nanorods through a one-pot solvothermal method. The hybrid nanorods have long time fluorescent property and higher quantum yield compared with pure CQDs, which can be used for longtime cell-imaging, and also have good drug loading and delivery property to kill cancer cells.

1D HAp nanostructures with different length can be synthesized controllably from nanorods (~200nm) to short nanowires (~5μm) to ultralong nanowires (over 50μm) by regulating experiment condition. Different 1D HAp nanostructures have different cytocompatibility and osteogenic differentiation promotion. Nanorods have low promotion to stem cell osteogenic differentiation although with high cytocompatibility. Cells can spread on ultralong nanowires hardly following low viability. Short nanowires possess both cytocompatibility and osteogenic differentiation promotion. It gives us a cue that nanostructures not only material properties play an important effect on stem cells regulation. Further, 1D HAp nanostructures can be combined with other bio-material to form composite and used in tissue engineering. A new kind of HAp/PLA composite with novel characteristic was prepared by ingenious design. The composite can repair defect region in precise, and provide huge convenience in modern medicine.

Through structure design and property optimization, it can be believed that 1D HAp nanostructures with tunable length and multi-functions will have very important and wide applications in biofield.

1. Baojin Ma, et al. "One-Dimensional Hydroxyapatite Nanostructures with Tunable Length for Efficient Stem Cell Differentiation Regulation." ACS applied materials & interfaces 9.39 (2017): 33717–33727

2. Baojin Ma, et al. "Prolonged fluorescence lifetime of carbon quantum dots by combining with hydroxyapatite nanorods for bio-applications." Nanoscale 9.6 (2017): 2162-2171

3. Baojin Ma, et al. "Eu/Tb codoped spindle-shaped fluorinated hydroxyapatite nanoparticles for dual-color cell imaging." Nanoscale 8.22 (2016): 11580-11587.

4. Baojin Ma, et al. " Hydroxyapatite Nanobelt/Polylactic Acid Janus Membrane with Osteoinduction/Barrier Dual Functions for Precise Bone Defect Repair." Submitted