Microfluidics for Biologists Fundamentals and Applications

2.4 Organs on Chips

These are the MF devices which are used for culturing living cells in micrometer-
sized chambers having a continuous supply of nutrients that mimic the physiolog-
ical functions of tissues and organs. Minimal functional organs that can recapitulate
tissue or organ level features are built so that‘near to real’conditions are available
for various experiments. Simplest system is a single, perfused MF chamber
containing only one kind of cultured cells exhibiting functions of one type of tissue,
e.g., hepatocytes or kidney tubular epithelial cells [ 26 , 27 ]. These systems are
utilized to study the organ-specific responses, different chemical stimuli (drugs,
toxins or other chemicals) and physical stimuli (physiologically relevant levels of
fluid shear stress, cyclic strain, and mechanical compression) [ 7 , 27 ]. Attempts have
been made to micro-fabricate models of blood vessels, muscle, bones, airways,

Cell culture

chamber layer

Siliconegasket

Liver

Top frame

Channel layer

Base

a

(A) (B)

b

c

a

b

cde

LiverTumorMarrow

Bottom frame

(other tissues)Reservoir

Tumor

Marrow

Organ

death

Cell

Kn

Kg

KK1Kn

Fig. 8.3 (A)(a) Photograph of the fully integrated platform showing its main components,
including the EXCELL potentiostat with a window for microscopic observations (inset). (b)
Schematic representation of an individual microfluidic chamber in the cell culture/detection unit
containing three electrode arrays. (c) Photograph of the reservoirs, showing the lid embedding the
gas connection used for pressurization. (d) Photograph of the microfluidic cell culture/detection
unit (e) Microscopic image of a single electrode array showing the counter (CE), reference (RE),
and working (WEa and WEb) electrodes [ 24 ]. (B) PBPK model of Sung et al. consisting of (a)
schematic of device fabrication (b) device operation steps (c) photograph of the device [ 25 ]

8 Biological Applications of Microfluidics System 199