3D Microfabrication

Boateng S, Lateef SS, Crot C, Motlagh D, Desai T, Samarel AM, Russell B, and Hanley L. Peptides bound to silicone membranes and 3D microfabrication for cardiac cell culture. Adv Mater, 2002, 14, 461 63. 

While a more detailed review of two-photon 3D microfabrication can be found in another chapter of this issue, this chapter will concentrate on our work on characterization and apphcation of commercial photoinitiators. The development of better 2PA photoinitiators would be expected to facilitate 3D photopolymerization technologies. Efficient 2PA compoimds based on phenylethenyl constructs bearing electron-donating and/or electron-withdrawing moieties have been reported [105-107]. Among these are electron-rich derivatives that have been found to undergo a presumed two-... 

In addition to these examples, an electron-transfer free radical photoinitiator H-Nu 470 (5,7-diiodo-3-butoxy-6-fluorone) has been also successfully used for 3D microfabrication by near-IR two-photon induced polymerization... 

It is noteworthy that nonlinearity of the absorption, required for 3D microfabrication can be provided via thermal mechanisms [53,54]. In the case of tightly focused laser pulses, linear absorption is most efficient at the focus, where local heating can create the conditions required for polymerization. Usually the absorption increases with temperature and thermal polymerization may become dominant at the focus. It is usually difficult to confirm the TPA mechanism from the direct transmission measurements due to the nar-... 

Zhou W, Kuebler SM, Braun KL, Yu T, Ober JKC, Ober CK, Perry JW, Marder SR (2002) An efficient two-photon-generated photoacid applied to positive-tone 3D microfabrication. Science 296 1106-1109... 

An additional class of nonlinear optical effects is that of multi-photon absorption processes. Using these process, one can create excited states (and, therefore, their associated physical and chemical properties) with a high degree of three-dimensional (3D) spatial confinement, at depth in absorbing media. There are potential applications of multi-photon absorbing materials in 3D fluorescence imaging, photodynamic therapy, nonlinear optical transmission and 3D microfabrication. 

The use of TP initiated polymerization for 3D microfabrication has several advantages over OP initiated polymerization. A 3D resolution can be achieved with lateral and depth resolutions of 0.2 pm and 0.28 pm. This is fabrication at a... 

Figure 3.71. Optical system used for 3D microfabrication using TP initiated polymerization of a photopolymerizable composition. The numerical aperture of the objective lens is 0.85 (magnification of 40), the accuracy of the galvano-scanner set and the dc motor scanner were 0.3 and 0.5 pm, the beam power at peak in the photocrosslinkahle composition is about 3 kW, with a repetition rate of 76 MHz and a pulse width of 130 fs at a wavelength of 770 nm [76].

TPA photoinitiators, with good reducing properties for radical creation, have been designed for 3D microfabrication following incident laser wavelengths. RAl and RA2 (Fig. 13) have been used at 532 nm [100,101]. For the... 

NLO transmission, and 3D microfabrication. However, there have been rather few studies of organometallic compounds at this time, especially studies in which two-photon spectra have been determined. 

D microfabrication 3D micromachining Microfabrica-tion of three-dimensional microstructures Three-dimensional patterning Fabrication of 3D microfluidic channels... 

Bianchi, F., Vassalle, C., Simonetti, M., Vozzi, G., Domenici, C., Ahluwalia,A. (2006). Endothelial cell function on 2D and 3D microfabricated polymer scaffolds Applications in cardiovascular tissue engineering. JBiomater Sci., Polym 17, 37-51. 

An efficient two-photon-generated photoacid applied to positive-tone 3D microfabrication. Science, 296 (5570), 1106-1109. 

Generative laser-based techniques for 3D microfabrication are widely used and their importance is likely to grow as the need for rapid prototyping and manufacturing as well as customization of a variety of products is increasing. 

Han, M., et al., 2004.3D microfabrication with inclined/rotated UV lithography. Sens. Actuators... 

Different from two-photon photopolymerization, fabrication based on positive polymers should be called two-photon depolymerization. It could be an important complementary technology in 3D microfabrication, particularly those with many buried structures like those in a micro fluid system. 

Belloy et al. [36,38] investigated the oblique powder blasting, in which the jet of abrasive particles is directed to the masked workpiece at an angle different from normal incidence, which opens the way to new underetching effects and perspectives in the 3D microfabrication. A symmetrical shape is created if the abrasive particles impact the surface at normal incidence. An oblique particle impact, however, i.e. at an angle away from 90°, leads to the formation of an asymmetrical erosion profile. More material is removed in the... 

---