System and method of measuring cell viability and growth
A novel SH-SAW biosensor capable of non-invasive and touch-free detection of cancer cell viability and growth or proliferation in two-dimensional (2D) and three-dimensional (3D) cell cultures as well as stem cell regeneration as it pertains to cancer cell biology and anti-cancer drug development is presented. The biosensor includes two pairs of resonators including interdigital transducers reflecting fingers to quantify mass loading by the cells in suspension as well as within a tumoroid culture platform. The biosensor can be part of a perfused 3PNS-tumoroid system that is amenable to real-time non-invasive monitoring of the cell proliferation, viability, and multiplexed detection of key physiologic and clinical biomarkers.
1. A non-invasive and touch-free method of detecting and quantifying cell growth and viability comprising:
providing a microfluidic chip containing a shear horizontal-surface acoustic wave device comprising:
two pairs of resonators formed on a lithium tantalate substrate wherein each resonator is comprised of at least two interdigital transducers, each having at least one pair of reflecting fingers;
at least one pH measurement electrode, at least one oxygen measurement electrode, at least one impedance measurement electrode and at least one interdigitated electrode formed on the lithium tantalate substrate;
an oscillatory circuit system connected to the two pairs of resonators, the oscillatory circuit system comprising
a pair of band pass filters, each filter connected to one end of each pair of resonators;
a pair of amplifiers, each amplifier connected to an opposing end of each pair of resonators wherein the connection of each band pass filter and each amplifier to each pair of resonators forms a closed-loop system;
an oscilloscope connected to the closed loop system by a T-connector; and
a digital frequency counter connected to the closed loop system by the T-connector; and
at least one Y-shaped polydimethylsiloxane (PDMS) microfluidic channel bonded to the lithium tantalate substrate wherein the at least one microfluidic channel contains an inlet access opening, an outlet access opening, at least one carbon dioxide access opening and a resealable access opening to a chamber;
wherein each transducer is coated with a substance selected from the group consisting of zinc oxide (ZnO), silicon oxide (SiO 2 ), silicon nitride (Si 3 N 4 ), titanium oxide (TiO 2 ), poly (methyl methacrylate) (PMMA), poly(chloro-p-xylylene) (Parylene-C) and an epoxy-based negative photoresist;
positioning a polymeric nanofibrous scaffold used to grow tumoroid cells on the lithium tantalate substrate;
seeding the cells into the at least one Y-shaped microfluidic channel;
applying a surface acoustic wave (SAW) to the cells; and
quantifying cell concentration using the oscillatory circuit system by measuring an oscillation frequency shift caused by relative change in SAW velocity using the digital frequency counter to count relative frequency response of the cells over a period of time;
wherein the relative frequency response of the cells over time determines the cell growth and viability.
2. The method of claim 1 , wherein the lithium tantalate substrate is a 36° Y-cut LiTaO 3 substrate.
3. The method of claim 1 , wherein number of pairs of reflecting fingers is 30 pairs.
4. The method of claim 1 , wherein the pair of band pass filters eliminate frequencies below 5 MHz and above 20 MHz in the closed loop system.
5. The method of claim 1 , wherein the coating is ZnO.