Micropatterned Photodegradable Hydrogels for the Sorting of Microbeads and Cells

摘要

Microarrays of biomolecules and cells have played important roles in genomics, diagnostics, and drug screening. Live-cell capture on micropatterned surfaces is particularly valuable for diagnostic or biosensing applications, as cell arrays are amenable to rapid characterization and sorting. For example, antibody-coated micropost arrays have been used to detect and isolate rare circulating tumor cells from peripheral blood with high fidelity. Microwell arrays have been used for the capture and analysis of single immune cells. While it is often important to release or sort subsets of cells from these arrays for more thorough downstream analysis (e.g. by PCR or Western blot), methods for the retrieval of specific cells from micropatterned surfaces remain limited. Electrochemical stimulation can be exploited to release cells from particular regions within micropatterns,but these approaches require that cell arrays be registered with electrodes, and they can become somewhat complicated for larger arrays. Arguably, light-activated cell-release strategies provide more flexibility, particularly for retrieval from highly dense arrays. Laser capture microdissection or laser catapulting can be used to remove specific cells from micropatterned surfaces, but the former approach works with fixed cells while the latter involves harsh conditions, often resulting in cell injury. Another example of light-activated cell sorting is the micro-pallet array developed by Albritton et al., in which cells are cultured on polymer microstnlctures (e.g. photoresist patterns) that can later be dislodged from the surface by laser pulses.