In vivo assessments for predicting the bioavailability of nanoencapsulated food bioactives and the safety of nanomaterials

Use of nano-sized materials to design novel delivery systems is actually a double-edged sword regarding the enhancement of absorption and bioavailability of encapsulated bioactives as well as the unpredictable phenomena inside the living cells causing health concerns. So, comprehensive investigations on the use of nanomaterials in foods and their biological fate are needed. To reach this goal, both in vitro and in vivo techniques have been extensively applied. Besides the in vitro models such as cell culture and yeast/bacteria, different live animal models like mice, rat, Drosophila melanogaster, Caenorhabditis elegans, Zebrafish and dog can be applied to study bioavailability and safety of nanodelivery systems. However, considering the low correlation between the achieved results of in vitro and in vivo assays, in vivo tests are the first priority due to providing a real physiological condition. On the other hand, uncorrelated results by in vivo assays represent a serious problem to compare them. To defeat the issues in setting an in vivo research for the nanodelivery systems, all restrictions and FDA regulations is likely to be considered to improve the assays authenticity. This review takes a comprehensive look at the different types of in vivo assays and model organisms that has been utilized for the investigation of bioavailability, release profile and possible toxicity of food-based nanomaterials so far.