Nanopatterns with biological functions

Both curiosity and a desire for efficiency have advanced our ability to manipulate materials with great precision on the micrometer and, more recently, on the nanometer scale. Certainly, the semiconductor and integrated circuit industry has put the pressure on scientist and engineers to develop better and faster nanofabrication techniques. Furthermore, our curiosity as to how life works, and how it can be improved from a medical perspective, stands to gain a great deal from advances in nanotechnology. Novel nanofabrication techniques are opening up the possibilities for mimicking the inherently nano-world of the cell, i.e., the nanotopographies of the extracellular matrix (ECM) and the nanochemistry presented on both the cell membrane and the ECM. In addition, biosensing applications that rely on fabrication of high-density, precision arrays, e.g., DNA or gene chips and protein arrays, will gain significantly in efficiency and, thus, in usefulness once it becomes possible to fabricate heterogeneous nanoarrays. Clearly, continued advances in nanotechnology are desired and required for advances in biotechnology. In this review, we describe the leading techniques for generating nanopatterns with biological function including parallel techniques such as extreme ultraviolet interference lithography (EUV-IL), soft-lithographic techniques (e.g., replica molding (RM) and microcontact printing (muCP)), nanoimprint lithography (NIL), nanosphere lithography (NSL) (e.g., colloid lithography or colloidal block-copolymer micelle lithography) and the nanostencil technique, in addition to direct-writing techniques including e-beam lithography (EBL), focused ion-beam lithography (FIBL) and dip-pen nanolithography (DPN). Details on how the patterns are generated, how biological function is imparted to the nanopatterns, and examples of how these surfaces can and are being used for biological applications will be presented. This review further illustrates the rapid pace by which advances are being made in the field of nanobiotechnology, owing to an increasing number of research endeavors, for an ever increasing number of applications.