**Acknowledgements**

Author is grateful to Department of Science and Technology, Government of India for providing INSPIRE Faculty award to pursue independent research.

### **Author details**

More reliable and sustainable sources of human cells, especially disease‐specific cells that are acquiescent to *in vitro* culture in OOC and phenotypically are true representative of their *in vivo* counterparts are required. To overcome this hurdle, human embryonic stem cells and iPS cells can be engineered to suit specific needs in the development of OOC [3, 156]. The OOC models with stem cells can generate and control physiologically relevant structural, biochem‐

With the new avenues opened by OOC in drug development, there is a need of fabricating human on‐chip or multiorgan on‐chip devices and to maintain a balance between the com‐ plexity and practicality will play an important role in their wide applications. With the improvement in physiological relevance, complexity in the model is obvious that presents major challenges to practical operation and management of the system. Accurate identification of minimal subset of cells and microenvironmental factors will be helpful to create a balance and designing a simplest model possible that recapitulates physiological responses of interest.

Integration of laboratory on‐chip platforms with miniaturized analytical systems is also important for better detection sensitivity despite of low culture volumes and cell numbers [1].

OOCs are not universal solutions, and alternative tools will continue to be better solutions for modeling certain *in vivo* processes as animal offer whole‐organism toxicity testing and this parallel analysis will be required until the current OOC scenario attains the maturity and refine

Despite their limitations, OOCs have the potential to play a transformative role across drug discovery and development. Eventually, OOC models may play a pivotal role in streamlining the clinical trial process. Due to the complexities of organ function and regulatory require‐

However, with the scientific advancements, this field is evolving at a fast pace and these hurdles could be surmountable with tri‐lateral partnerships between academic institutions, industry and regulatory agencies. The paradigm‐shifting potential of OOC technology has been recognized by funding agencies integrated microphysiological systems [157, 158]. Pharmaceutical companies are also coming forward to establish industry‐ academia partner‐ ships to jointly explore this emerging research arena and to establish themselves at the forefront of expected OOC advances. In nut shell, it is concluded that despite of several limitations, achievements in this revolutionary field of biomedicine, OOC technology present exciting new avenues for drug discovery and development and a perfect picture of a promising future.

Author is grateful to Department of Science and Technology, Government of India for

providing INSPIRE Faculty award to pursue independent research.

ments, it is unlikely that OOCs will replace animal testing anytime soon [66].

human on‐chip systems come into existence.

114 Lab-on-a-Chip Fabrication and Application

**Acknowledgements**

ical and mechanical cues required for stem‐cell differentiation and maturation.

Preeti Nigam Joshi

Address all correspondence to: ph.joshi@ncl.res.in

Organic Chemistry Division, National Chemical Laboratory, Pune, India
