# Nanotechnology in Plant Metabolite Improvement and in Animal Welfare
## 1 Introduction
Previous studies have shown that metallic (Ag-, Au-, and Fe-nanoparticles) and metal oxide nanoparticles (nano-ZnO\({}_{2}\), -TiO\({}_{2}\), and -CuO\({}_{2}\)) positively impact plant tissue culture by supporting morphological potential and propagation, as well as improving plant resistance to stress [12; 26; 28]. Silver-nanoparticles (AgNPs) have raised great interest due to their strong biological activity, resulting in outstanding anti-microbial performance, and their hormetic effects, which, in appropriate doses, lead to the improvement of plant biomass as well as secondary metabolite accumulation. However, the molecules inhibit plant growth in high doses [28; 29]. These AgNPs nanoparticles affect plants at many different levels, resulting in stimulation of plant germination and growth, biomass accumulation, improved shoot induction and proliferation, and enhancement of pigment content [28]. Numerous positive results have been gained from nanotechnology in plant tissue culture, where the involvement of nanoparticles has become a promising method of increasing effective plant propagation and production. A recent report [8] showed the effective propagation and secondary metabolite enhancement of the endangered plant species _Caralluma tuberculata_ via AgNP elicited culture. It has been demonstrated that a combination of AgNPs and plant growth regulators increased callus biomass as well as total phenolics and flavonoids. This review mainly focuses on the most recent progress and achievement in AgNP elicitation in plant tissue culture for the purpose of secondary metabolite enhancement. Their effect on plant growth and biomass accumulation as well as the possible mechanism of action and some perspectives of the use of nanomaterials as potential therapeutic agents are also reviewed and presented. The final section of this contribution is dedicated to the application of nanotechnological to fields different from plants but rather to animal model systems. This is actually a major field of expertise in the laboratory of one of the authors (GR). Due to the very high versatility of the carbon-based nanoparticles, the reader is addressed to Section 5 of this work for a comprehensive illustration and discussion of the most common entities. In particular, their potential delivery action into recipient cells and/or whole organisms is examined. With respect to his specific usage of cargo nanoparticles loaded with bioactive principles of botanical origin, scientific literature exists. Natural raw materials from plants are since the dawn of ages used as therapeutic drugs well as other diverse tools in herbal treatments, food, and cosmetics. The phyto-molecules isolated from the medicinal and aromatic plants have become a commodity of primary demand within the pharma industry. However, some drawbacks exist since phyto-molecules may show limited absorption, not well-defined bioavailability, and at times disputable efficacy: see for instance the case of neem oil and its derivates [30]. Phytomolecules or compounds of essential oils from medicinal and aromatic plants like camptothecin, curcumin, thymol, and eugenol, for instance, may show reduced solubility in pure form which hinders their bioavailability and efficacious uptake by the target cell/organ. This represents a serious limitation in their biomedical application. These limitations may be overcome by using nanotechnological tools. This was discussed in a relatively recent review article. Specifically, improvement of the biological activity and delivery was observed after phyto-molecules encapsulation in the nanocarriers. In conclusion, the combinatorial application of plant products with medicinal properties and nanotechnology would be advantageous in the healthcare area [31]. Regarding this point, it has been extensively discussed that the \"conventional\" antitumor therapy may show a significant improvement using a combination of drugs incorporated into nano-delivery drug systems.