Biology

Fabrication of tunable micropatterned substrates for cell patterning via microcontact printing of polydopamine with poly(ethylene imine)-grafted copolymers

Abstract

Cell patterning is an important tool for biomedical research. In this work, we modified a technique combining mussel-inspired surface chemistry and microcontact printing (μCP) to modulate surface chemistry for cell patterning. Polymerized dopamine on poly(dimethylsiloxane) stamps was transferred to several cell-unfavorable substrates via μCP. Since cells only attached to the polydopamine (PDA)-imprinted areas, cell patterns were formed on a variety of cell-unfavorable surfaces. The stability of PDA imprints was proved under several harsh conditions. The cell affinity of PDA was modulated by co-deposition with several poly(ethylene imine) (PEI)-based copolymers, such as PEI, PEI-g-PEG (poly(ethylene glycol)) and PEI-g-galactose. The imprints of PDA/PEI-g-PEG provide the formation of cell patterns on cell-favorable substrates. Neuronal PC12 cells were patterned via imprinting of PDA/PEI, while HepG2/C3A cells were arranged on the imprint of PDA/PEI-g-galactose. Finally, co-culture of HepG2/C3A cells and L929 fibroblasts was accomplished by our micropatterning approach. This study demonstrated this simple and economic technique provides a powerful tool for development of functional patterned substrates for cell patterning. This technique should profit the preparation of cell patterns to study fundamental cell biology and to apply to biomedical engineering such as cell-based biosensors, diagnostic devices and tissue engineering.

Link

Fabrication of tunable micropatterned substrates for cell patterning via microcontact printing of polydopamine with poly(ethylene imine)-grafted copolymers

Microcontact printing of polyelectrolytes on PEG using an unmodified PDMS stamp for micropatterning nanoparticles, DNA, proteins and cells

Abstract

A facile microcontact printing method has been developed based on directly printing polyelectrolytes on a glass or polystyrene surface coated with poly(ethylene glycol) (PEG) silane using an unmodified poly(dimethyl siloxane) (PDMS) stamp. The method is applicable to a variety of polyelectrolytes including poly(allylamine hydrochloride) (PAH), poly(diallyldimethylammonium chloride) (PDAC), branched and linear poly(ethylene imine) (PEI), poly-L-lysine (PLL), chitosan, double stranded DNA, and poly(sodium 4-styrene sulfonate) (PSS). The printed polyelectrolyte structures, which include monolayer, bilayer, and stretched molecular bundles, are stable in aqueous solutions and have been used as templates for micropatterning quantum dot nanoparticles, DNA, proteins, and live cells.

Link

Microcontact printing of polyelectrolytes on PEG using an unmodified PDMS stamp for micropatterning nanoparticles, DNA, proteins and cells

Aqueous micro-contact printing of cell-adhesive biomolecules for patterning neuronal cell cultures

Abstract

Micro-contact printing (μCP) technique has been widely used for generating micro-scale patterns of biomolecules for patterning live cells. The contact-printing process is carried out in air, while most of the biomolecules including proteins and antibodies should be handled in a solution to preserve their bioactivity. Here we attempted to print biomolecules under aqueous conditions by modifying certain steps that are known to be critical for the bioactivity. The proposed contact-printing process is as follows: After inking the stamp with biomolecule in a solution, the stamp was rinsed in ultra-sonication bath to remove excessive inked biomolecules on the stamp and the following contact-printing process (‘stamping’) was carried out in a buffered solution. By this way, inked biomolecules were consistently handled under a well-defined aqueous condition. Results showed that high-resolution micropatterns of biomolecules can be printed under the aqueous condition (aqueous micro-contact printing, aq-μCP) and it was readily applicable for patterning neuronal cell cultures. Using the modified process, we were able to print widely separated patterns (2 μm-wide lines with 400 μm spacing), which was not achievable with conventional μCP. Extracellular matrix proteins (laminin and fibronectin) were readily printed in a few micrometer scale patterns and their biological activities were confirmed by immunoassays and neuronal cell cultures. We also demonstrated that pH sensitive surface biofunctionalization scheme can be implemented with the proposed aq-μCP for patterning neuronal cell cultures. The aq-μCP improves the existing surface patterning strategy by extending printable patterns and proteins for neuronal cell chip design.

Link

Aqueous micro-contact printing of cell-adhesive biomolecules for patterning neuronal cell cultures

Page 4 of 35