The use of dual beam ESEM FIB to reveal the internal ultrastructure of hydroxyapatite nanoparticle-sugar-glass composites

摘要: Microparticles (MP) spray dried from hydroxyapatite (HA) nanoparticle (NP) sugar suspensions are currently under development as a prolonged release vaccine vehicle. Those with significant component cannot be sectioned by ultramicrotomy resins excluded the sugar. Focused ion beam (FIB) milling is only method to prepare thin sections that enables inspection of MPs ultrastructure transmission electron microscopy (TEM). Several methods have been explored and we found it simplest encapsulate in silver dag, sandwiched between gold foils for FIB-milling enable multiple simultaneously. Spray containing 80% an inter-nanoparticle separation comparable NP size (~50 nm). 50% or no more tightly packed. Nano-porosity order 10 nm exists NPs. absence nanoscale morphologies. Selected area diffraction (SAED) demonstrates HA remains (substantially) crystalline following FIB-milling.