Photofabrication of 3D Protein Hydrogels for Nanobiotechnology Applications

BAYINDIR GROUP JOURNAL CLUB-1

Erol Özgür

MOTIVATIONS

• Microfabricated platforms in cellular biology: valuable research tools

• Microfluidics technology• Major problem is biocompatibility• Limited functionality of interfacial materials• No perturbation during experiment process is possible

• Aim: Platforms for cellular research that could be modified in situ

Protein Cross-linking for Formation of 3D Hydrogels

• BSA (Bovine Serum Albumin) is a soluble protein with 607 residues

• BSA(aq) BSA(prec.)

• UV light: Inefficient, little control on the shape

• Multiphoton excitation: Precisely controlled submicrometer sized shapes

• Photosensitizers increase the efficiency of the process

• Optical parameters:Tsunami Ti:Sapphire laser at 730-740 nm, Zeiss Axiovert IM 100X Fluar 1.3 NA objective, with a confocal scanner

hν

In Situ Formation of Protein Hydrogel

3D Protein Hydrogels Created by Photofabrication with Photomasks

Chemical Response of Protein Hydrogels: Na2SO4

Chemical Response of Protein Hydrogels: Na2SO4

Chemical Response of Protein Hydrogels: pH from 7 to 12.2 with NaOH

Microchambers with E. coli Directionality

Microvortex Created by E. coli

Axial Fluid Flow in an Arched Microchannel Produced by Flagellar Motion of E. coli

Orbital Revolution of a PMMA microdisk by E. coli

Different Strategies in Photofabrication

With Photomask and Confocal Scanner

With Digital Micromirror Device

Fabrication Process with DMD

Some Structures Fabricated with DMD

References

Kaehr, B. and J. B. Shear (2008). "Multiphoton fabrication of chemically responsive protein hydrogels for microactuation." PNAS 105(26): 8850-8854.

Kaehr, B. and J. B. Shear (2009). "High-throughput design of microfluidics based on directed bacterial motility." Lab on a Chip 9(18): 2632-2637.

Nielson, R., B. Koehr, et al. (2009). "Microreplication and Design of Biological Architectures Using Dynamic-Mask Multiphoton Lithography." Small 5(1): 120-125.