Non-invasive microwave sensor for the detection of the cell culture medium residues

A metallic circular tapped split ring resonator (CT-SRR) coupled with coplanar waveguide (CPW) are designed and fabricated for the non-invasive measurement of the cell (fibroblasts and adipocytes) culture medium residues (MRs), comprising remaining nutrients (glucose and electrolytes), serum, and other substances following cell cultures. Pre-culturing MRs were prepared with the same standard formulas and divided into four cases, i) pre - MRs with serum, ii) pre-MRs with serum and herb extract, iii) pre-MRs with serum and hormones and iv) pre-MRs with serum, hormones and herb extract. The four cases of culturing MR preparations are measured and analyzed by the proposed microwave sensor through transmission coefficient (S21) in the frequency range from 1.5 GHz - 2.5 GHz. The experimental results show that the highest of S21 and cells fat accumulation activity in case (iv) which related to the lowest remaining nutrients. The order amplitude of S21 at 1.96 GHz with material under tests (MUTs) at 1.96 GHz as follows: case (iv) > case (ii) > case (i) > case (iii) > DI water > air. The results demonstrate the feasibility of a non-invasive microwave based biochemistry sensor technology.