Project Objective:

Currently, there is great interest in designing smart material capable not only of directing cell processes, but also of monitoring them. This idea could in principle be realised by transforming a conventional scaffold into a “smart scaffold” that acts as a sensor for monitoring cell activities.

Figure 1: (A) our 3D scaffold; (B) realised 3D “Smart” scaffold; (C) the magnification of our smart scaffold

Short description of the system

Cell activities such as adhesion, proliferation and protein secretion will modify the electrical properties of their substrate. Therefore it is possible to monitor their activity by monitoring the impedance of the scaffold.

As the first step of this investigation, we used PLLA/CNT membranes to test the feasibility the using composite conductive materials as sensorised scaffolds. HepG2 cells were cultured on the sensors and their impedance was monitored over time.

Figure 2: (A) Theoretical scheme of our impedance measurement; (B) step by step of cell measurement using PLLA/CNT sensorised membrane and (C) microscope image of the cells onto the membrane after experiment

Figure 3: (A) Monitoring of impedance magnitude of PLLA/CNT sensorised membrane for 24 hours; (B) the impedance change w.r.t. to its initial time (in percentage) and (C) impedance change of sensorised membrane with and without cells seeding.

We have been shown the result that the material are nontoxic for cells and able to be adhered. Moreover, certain signals were obtained to correlate with the cells activities more in protein expression. The cell adhesion on the surface is confirmed by an impedance change of 10-20%.

Furthermore, we propose an equivalent circuit model of the system to determine a suitable working window in terms of frequency range and to enable interpretation of the measurements. Finally 2 and 3 dimensional scaffolds were microfabricated using PAM to assess the suitability of the composite for processing as a biomaterial.