Self-adhesive microculture system for extended live cell imaging

Abstract

Gas permeable and biocompatible soft polymers are convenient for biological applications. Using the soft polymer poly(dimethylsiloxane) (PDMS), we established a straightforward technique for in-house production of self-adhesive and optical grade microculture devices. A gas permeable PDMS layer effectively protects against medium evaporation, changes in osmolarity, contamination and drug diffusion. These chip-based devices can be used effectively for long term mammalian cell culture and support a range of bioassays used in pharmacological profiling of anti-cancer drugs. Results obtained on a panel of hematopoietic and solid tumor cell lines during screening of investigative anti-cancer agents corresponded well to those obtained in a conventional cell culture on polystyrene plates. The cumulative correlation analysis of multiple cell lines and anti-cancer drugs showed no adverse effects on cell viability or cell growth retardation during microscale static cell culture. PDMS devices also can be custom modified for many bio-analytical purposes and are interfaced easily with both inverted and upright cell imaging platforms. Moreover, PDMS microculture devices are suitable for extended real time cell imaging. Data from the multicolor, real time analysis of apoptosis on human breast cancer MCF-7 cells provided further evidence that elimination of redundant centrifugation/washing achieved during microscale real time analysis facilitates preservation of fragile apoptotic cells and provides dynamic cellular information at high resolution. Because only small reaction volumes are required, such devices offer reduced use of consumables as well as simplified manipulations during all stages of live cell imaging.

Dynamic Analysis of Drug-Induced Cytotoxicity Using Chip-Based Dielectrophoretic Cell Immobilization Technology

“…The increase in temperature will therefore lead to large evaporative losses that were confirmed during the initial validation of our prototypes (data not shown). Our recent studies, however, have added new evidence that use of a PDMS substratum can limit evaporation from enclosed chips and thus allow for a sustained, static microculture without profound variations in, for example, drug concentration or osmolarity. , Accordingly, a self-sealing cover, a 1 mm layer of PDMS was cast and cured, as a lid, using the general methods as described above. DEP devices with actuated electrode arrays, when used in conjunction with the conformally bonded polymeric lid, resulted in water loss by evaporation being reduced to <10% (v/v) over extended incubation periods. , As shown by us previously, the reusable lid allowed also for repetitive DEP cell manipulations using only standard liquid handling and pipetting systems. , …”

“…Cured devices were mechanically diced and attached to the PMMA parts. In some experiments the biocompatible elastomer polydimethylsiloxane (PDMS) was solely used to fabricate the microculture chambers where elliptical chambers were manually bored using an appropriate stainless steel punch hole as described earlier. , To fabricate a self-sealing cover that reduces the evaporative water loss and prevents contamination, a 2 mm layer of PDMS was cast and cured, as a lid, using the general methods as described above. , …”

“…Student’s t test was applied for comparison between groups using SPSS 11 (Chicago, IL) with significance set at p < 0.05. All control measurements are provided in detail in the Figure legends, where appropriate, but in general involved making direct comparisons between the DEP devices and polymeric chips without integrated electrodes as described earlier. , …”

Automated Lab-on-a-Chip Technology for Fish Embryo Toxicity Tests Performed under Continuous Microperfusion (μFET)

“…Microfluidic technologies allow application of laminar fluid flow at ultralow volumes in the spatially confined chip-based microchannel circuitry . Biocompatible and inexpensive polymers such as poly­(dimethylsiloxane) (PDMS) elastomer and poly­(methyl methacrylate) (PMMA) transparent thermoplastic are often materials of choice for fabrication of disposable microfluidic devices. − Finally, merging of LOC technologies with sophisticated optoelectronic sensors, mechatronic interfaces, and dedicated embedded computing is a powerful avenue to develop high-throughput toxicity screening platforms …”

Towards single-cell LC-MS phosphoproteomics

“…This figure indicates milestones for both technologies and their intersection times. Proteomics milestones are based on 'Proteomics of industrial fungi: trends and insights for biotechnology' by de Oliveira et al 8,28,60,65,75,86,106,118,134,135,[159][160][161][162][163][164][165][166][167][168][169][170][171] and microfluidics milestones are based on 'Timing is everything: using fluidics to understand the role of temporal dynamics in cellular systems' by Jovic et al 8,102,[171][172][173][174][175][176][177][178][179][180][181] used in a lysis buffer and their applications can be found in the literature. 18,30 Depletion of surfactants and protein inhibitors is a prerequisite for an efficient mass spectrometric analysis; because favourable ionizability of surfactants and relative abundance of some proteins hamper the peptide spectrum.…”