**11. Conclusions**

parts including brains suggests that physio-chemical properties including shapes, surface

The key parameters of nanomaterials for easy and efficient delivery are shape, size and flexibility to enter and exit cell barrier. Our results clearly demonstrate that the properties of each acid side chain together with common PABA moiety influences size, shape and surface texture of nanomaterials that lead to differential uptakeand specificity in live cell delivery. The physio-chemical modifications of organic nano carriers also affect cell internalization mecha‐ nisms in sub-cellular organelles as found by distinct accumulation pattern of each nanomate‐ rials following same energy dependent endocytosis. In vivo screening also showed that only C 11 and C-16 produce compatible shape and size of nanomaterials that are best fitted for easy delivery of PABA nanomterials. These results suggest that physical structure of nanomaterials and chemical properties of acid side chain required for self assemble procedure and size

In addition to cultured cells, tissue specific distribution specifically in adult eyes, imaginal discs, alimentary tracks and neuronal tissues was complex and needs more parameter to consider. Our data revealed that a complex interrelationship of PABA conjugates and cell physiological environment is important in live materials delivery. The internal tissue envi‐ ronment might provide additional barriers for nanomaterial entry as depicted by comparing variable accumulation of same nanomaterials in cross species; Drosophila and human cell lines. A similar difference was also noticed when C-11 or C16 accumulation was compared in multiple complex organ of Drosophila. However, nanomaterials compatible for oral delivery do not show any short-term toxicity, impaired growth of Drosophila larvae and adults. We hypothesize that two distinct parameter nano-skeleton frame with conjugated acid chains and live cell physiology are best suited for cell uptake and delivery to internal organs after oral consumption. Our results also differ from the hypothesis that nano-particle uptake in live cells occurred through energy independent non-endocytotic pathway involving insertions and diffusion across the cell membrane. Sub cellular internalization of PABA nanomaterials predominantly takes place by energy dependent endocytosis. Earlier we have found that PABA nanomaterials can penetrate plasma membrane in the human cells and enter into cytoplasm. The variable amount of different nanomaterial accumulation by energy dependent endo-cytosis in same cell type ruled out the possibility that a single internalization mechanism, endocytosis is exclusively required for uptake. However, a marked reduction of different nanomaterials under endocytosis inhibitory conditions believed that such discrepancies are due to sharp differences in size and shape of the self assembled structures. In addition as organic nanomaterials suffer from uncontrolled aggregation to form micron sized particles after prolong storage; thereby ruling out the possibility of insertion, diffusion and penetration mechanisms [22]. PABA nanoparticles have a high tendency to associate with cell membrane

texture of the C-11 and C-16 particles are the best-fitted materials (Figure 4).

variation could be the initial step for cellular uptake.

**10. Perspective**

464 Application of Nanotechnology in Drug Delivery

(Figure 2, 3).

We have shown that two carbon linker group C-11 and C-16 forms tubular nanomaterials that are best fitted for mass oral delivery in complex multiorgans. The cellular uptake mechanism is energy dependent endocytosis. The detailed endocytosis pathways for nano PABA structure is operated thorough clathrin-coated pits rather than caveolae or lipid rafts. In vivo screening of PABA nanomaterials produced by different acid side chain select the compatible nano structure ideal for oral delivery and establishes energy dependent entry mechanism is of fundamental importance that will facilitate future developments of PABA nanoparticle transporters for biological delivery application
