Date of Award

2013-01-01

Degree Name

Doctor of Philosophy

Department

Engineering

Advisor(s)

Thomas Boland

Second Advisor

Bill Tseng

Abstract

The new paradigm of personalized medicine is beginning to affect clinical practice. In particular, many of the advances in genomics and proteomics have made personalized screening and therapeutic inventions possible. On chip, cellomics approaches to screening and intervention are becoming more commonplace. Cancer therapies may benefit from the rise in `-omics' technologies. In addition, the availability of rapid screening data is crucial to mitigate cancer propagation and increase the possibility of patient recovery. This study is an endeavor to develop a cellomic anticancer drug screening process based on inkjet printing. Previous research has demonstrated that inkjet based screening can reliably create isolated spots arrays at low volume (180 pl) and high throughput (213 spots/sec). Herein we study whether inkjet printing small volumes of anticancer drugs along with few cells has merit as a tool to fabricate cellomic chips. Inkjet printing has the potential to minimize drug use and maximize the use of cell biopsies.

Cells, from the hepatocellular carcinoma line HepG2 and the epithelial cell line PHEC, were printed with an inkjet device and thus arrayed on a 96-well plate for culture. The inkjet device was described before [1]. At mean exponential proliferation rate, cyclophosphamide monohydrate (Cytoxan) and dichloroacetate sodium (DCA) at standard chemotherapeutic concentrations in the range of 1-50 mM were printed at continuously increasing densities in order to expose cultures to a drug concentration gradient. Anticancer drugs were studied under two solvents by means of dimethyl sulfoxide and PBS. The printed volumes were in the nanoliter range accounting for 625 ± 20% cells per spot. MTS assay was utilized to determine the amount of viable cells upon 24 hours of drug exposure followed by 48 hours for cell recovery. Half maximal and 90 percent inhibitory concentrations (IC50, IC90) were obtained from the dose-response curve. Along with the proposed cellomic chip, a screening platform using traditional micropipetting technique was built to compare results and validate inkjet based screening platform applicability.

Results obtained show that both cell lines were growth inhibited under both drug regimens. The IC50 values obtained by micropipetting and inkjet based screening varied less than 1mM suggesting that the proposed screening platform closely mimics the traditional screening outcome. However the IC90 values obtained vary in the range of 1 to 4.5 mM. The resulted IC50 indicates that 9.35 and 4.3 mM will be sufficient to inhibit growth of both cell lines under cytoxan and DCA treatment, respectively. In comparison to literature, IC50 results vary based on the cell lines used for the screening platform, but are generally in the range of 4-10 mM. Thus our results are consistent with those that used much larger volumes, validating our hypothesis that screening assays can be further miniaturized.

Inkjet technology shows promise to be used to determine dosages and treatment modalities using the patient's limited supply of biopsied cells. Expansion of the screening process to more drugs and usage of actual patients' biopsied cancer cells will result in valuable data to forecast efficiency of potential drug therapies.

Language

en

Provenance

Received from ProQuest

File Size

109 pages

File Format

application/pdf

Rights Holder

Jorge Ivan Rodriguez

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