Microtransponders, the miniature RFID electronic chips, as platforms for cell growth in cytotoxicity assays

Abstract

Background:An electronic radio frequency (RF) microchip, the microtransponder (MTP), has been developed as a platform for assays in the fields of genomics and proteomics. Upon activation by light, each MTP provides a unique RF identification (ID) signal that matches a chip to the specific biological material attached to it. The MTP is powered by a photocell and has an antenna that transmits the signal. The aim of the present study was to explore utility of MTPs as a platform for cell growth in cytotoxicity assays.Methods:The MCF‐7, MCF‐116, A549, or T‐24 cells growing on MTPs placed in petri dishes or slide chambers were cultured untreated or exposed to antitumor drugs topotecan, mitoxantrone, or onconase for up to 4 days. Their attachment to‐ and growth on‐ MTPs was assessed by fluorescence microscopy and laser scanning cytometry (LSC) and compared with growth on the dish surface in the MTP neighborhood. The MTPs were fixed in ethanol, stained with propidium iodide (PI), and interrogated in flow in the instrument capable to rapidly (up to 103 MTPs/s) identify their ID signal and measure fluorescence.Results:The cells plated on MTPs exhibited similar attachment properties to those plated in culture dishes. When measured by LSC, they had similar mitotic activity, growth rate, and cell cycle distributions as the cells adhering to the culture dish in the neighborhood of MTPs. The fluorescence intensity of MTPs provided information about the cell number per MTP, which made it possible to assess cell growth rate and monitor the cytostatic/cytotoxic effects of the tested drugs.Conclusions:The MTP‐based system holds promise for the multiplexed cell assays in which numerous different cell lines can be screened for their growth rate or sensitivity while exposed to particular agents in the same vessel. Other advantages of the system are the rapidity of the screening and a very large number of ID codes. Because many cell lines/types can be assayed in a single dish, the system also offers cost savings on tissue culture reagents. © 2006 International Society for Analytical Cytology

Silver nanoparticle-enhanced fluorescence in microtransponder-based immuno- and DNAhybridization assays

“…Probe identity is thus associated with a unique ID for each p-Chip. The p-Chip-based platform is designed to increase the flexibility and throughput of bioassays and has been successfully applied in multiplexed genotyping [19], proteomic and cytotoxicity assays [20]. …”

Encoded anisotropic particles for multiplexed bioanalysis

“…Fluorescence and RF readout is performed on individual particles in flow, at a rate of 1000 MTPs per second 102. Mandecki et al103 used MTPs as platforms for cell growth. These complex particles have also been used to detect 50 cystic fibrosis mutations by allele‐specific primer extension and hybridization of target sequences to capture probes covalently bound to the MTP 102.…”

Detection of unlabeled particles in the low micrometer size range using light scattering and hydrodynamic 3D focusing in a microfluidic system

“…The resulting variations in the measured light intensities are then used to obtain information about the passing particles, most importantly size, but also type or viability, in cases where cells are concerned instead of particles. Flow cytometry has shown to be a powerful tool for high‐throughput characterization of particles and cells in genetics, clinical marker identification, biochemistry, and developmental embryology []. However, entities smaller than cells (such as bacteria, viruses, or molecular assemblies) have great importance and widespread applications in medical diagnostics and therapeutics, and efforts are therefore underway to bring the power of cytometry also to this size domain [].…”