Printing of biomolecules

In terms of printing of biomolecules, there are several important factors that have to be considered. The affinity of the biomolecule to the stamp and to the substrate must be tailored so that it is higher for the substrate than for the stamp. The binding of the biomolecule should not cause denaturation (if applied, e.g., in case of proteins) and therefore should not affect the secondary or tertiary structure that can cause the unfolding of the molecule. The biomolecule should be attached to the substrate in a way that will expose all the active sites to the target molecules. 

This author and coworkers at Beckman Coulter first described the use of a low form 96-well plastic microplate for automated micro-ELISA immunoassays (Matson et al., 2001). The polypropylene plate was first modified by a radiofrequency plasma amination process (Matson et al., 1995) followed by conversion to an acyl fluoride surface chemistry for rapid covalent attachment of biomolecules. Proteins (1 to 2 mg/mL) were prepared in 50 mM carbonate buffer, pH 9, containing 4% sodium sulfate (to improve spot uniformity) and printed using a conventional arrayer system. Approximately 200-pL droplets of monoclonal antibodies (anti-cytokine) were deposited into the bottom of the microwells using a Cartesian PS7200 system equipped... 

Although such a variety of synthetic methods can be used to produce ZnO nanomaterials, the following section will provide an overview of synthetic procedures to produce ZnO nanomaterials that are further demonstrated for fluorescence detection of biomolecules [61-65], Specifically, the following section will focus on a gas-phase nthetic route exploiting microcontact-printed catalysts and describe an in situ m od for producing ZnO nanorod (ZnO NR) platforms in an array format The physical and optical properties of as-synthesized ZnO NRs will be also discussed. 

The authors of a biochemistry text face the problem of trying to present three-dimensional molecules in the two dimensions available on the printed page. The interplay between the three-dimensional structures of biomolecules and their biological functions will be discussed extensively throughout this book. Toward this end, we will frequently use representations that, although of necessity are rendered in two dimensions, emphasize the three-dimensional structures of molecules. 

Bioprinting on Chip, Fig. 1 Principle of microarray experiment. The microarray life cycle shows the five main steps needed for a microarray experiment [2]. (1) The biological question is the first step followed by (2) sample preparation including printing of the biomolecules onto the substrate. (5) The coupling of the capture molecules localized at predefined positions - the so-called spots - finalizes the microarray fabrication followed by... 

In this chapter, we will survey the kinds of solid supports (substrates) and surface chemistries currently used in the creation of nucleic acid and protein microarrays. Which are the best supports and methods of attachment for nucleic acids or proteins Does it make sense to use the same attachment chemistry or substrate format for these biomolecules In order to begin to understand these kinds of questions, it is important to briefly review how such biomolecules were attached in the past to other solid supports such as affinity chromatography media, membranes, and enzyme-linked immxm-osorbent assay (ELISA) microtiter plates. However, the microarray substrate does not share certain unique properties and metrics with its predecessors. Principal among these are printing, spot morphology, and image analysis they are the subjects of subsequent chapters. 

Most immobilizahon chemistries for microarrays currently rely upon derivatization of the substrate with amine-reactive functional groups such as aldehydes, epoxides, or NHS esters. While we can choose from many available surface-reactive chemistries, it is important to keep in mind that they must be compatible with a printing process. Ideally, the biomolecule should react completely and rapidly with the substrate in order to achieve good spot formation. It is also critical that the probe remain or be recoverable in its active state following printing. If too reactive a chemistry is employed there is the possibility for excessive crosslinking that can hinder performance by reducing the number of rotatable bonds in the probe. 

Stocklin, G. (1979). Chemical and biological effects of (8 -decay and inner shell ionization in biomolecules a new approach to radiation biology, page 382 in Radiation Research, Okada, S., IMAMURA, M., TeRASIMA, T, AND Yamaguchi, H., Eds. (Ibppan Printing Company, Tbkyo). 

---