Abstract: Disclosed is a perfusion device and methods of use including a generally cylindrical body and a packed bed of nanosensor-cell embedded matrix spheres (nanoCEMS) disposed between layers of inert microspheres. A concentration of a molecule of interest can be established within the perfusion device to effect the cellular and chemical microenvironment of the nanoCEMS, the nanoCEMS in turn creating their own concentration gradients nutrients and waste products in response, which can be measured by nanosensors. The collected measurements can be applied to a transport model to calculate concentrations of various molecules at discreet locations in the perfusion chamber. Also disclosed is a method for making nanoCEMS by mixing a polymeric mixture with a crosslinking solution and dispersed through a nested dispensing device such that mixing of the two mixtures occurs in air. A piezoelectric transducer coupled to the dispensing device controls the droplet formation rate.

Abstract: Sensitive mammalian cell mutants are rapidly isolated using flow cytometry. A first population of clonal spheroids is established to contain both normal and mutant cells. The population may be naturally occurring or may arise from mutagenized cells. The first population is then flow sorted by size to obtain a second population of clonal spheroids of a first uniform size. The second population is then exposed to a DNA-damaging agent that is being investigated. The exposed second population is placed in a growth medium to form a third population of clonal spheroids comprising spheroids of increased size from the mammalian cells that are resistant to the DNA-damaging agent and spheroids of substantially the first uniform size formed from the mammalian cells that are sensitive to the DNA-damaging agent. The third population is not flow sorted to differentiate the spheroids formed from resistant mammalian cells from spheroids formed from sensitive mammalian cells.