Hydrophilic surfaces, enhancement

Cellulose Hydrophilic surface, enhanced stability by cross-linking, inexpensive... 

The ProteinChip System from Ciphergen Biosystems uses patented SELDI (Surface-Enhanced Laser Desorption/Ionization) ProteinChip technology to rapidly perform the separation, detection, and analysis of proteins at the femtomole level directly from biological samples. ProteinChip Systems use ProteinChip Arrays which contain chemically (cationic, anionic, hydrophobic, hydrophilic, etc.) or biochemically (antibody, receptor, DNA, etc.) treated surfaces for specific interaction with proteins of interest. Selected washes create on-chip, high-resolution protein maps. This protein mass profile, or reten-tate map of the proteins bound to each of the ProteinChip Array surfaces, is quantitatively detected in minutes by the ProteinChip Reader. 

The quality of the thin film depends on preferential interactions between precursor and coating substrate. However, the initial layer is clearly the most important and, in the case of nanocarbons, the surface chemistry must be tailored. For most ALD precursors, hydrophilic surface groups enhance deposition, which can be achieved by functionalizing the nanocarbon prior to placement in the ALD reaction chamber or by treating the sample within the chamber with reactive plasma. Among the many in situ hybridization techniques, ALD provides best control of thin film thickness. 

In a related approach, arrays with different types of surface chemistries such as hydrophobic, hydrophilic, anionic, and affinity are used to absorb certain protein groups from biological or patient samples. The chip-absorbed proteins are then directly detected by surface-enhanced laser desorption/ionization time-of-flight MS (SELDl-TOF MS) (Issaq et al. 2002). The resulting protein masses can be used in pattern analysis and thereby provide a useful diagnostic tool. 

Strain-proofing and self-cleaning effects can be enhanced through the highly hydrophilic function. As an example, a plastic surface smeared with oil cannot be cleaned unless one uses detergent. A highly hydrophilic surface,... 

Spiropyran molecules have also been utilized as reverse wettable surfaces, whereby, a hydrophilic surface may be photomodulated to a hydrophobic surface and vice versa. Lygeraki et al. utilized the polar (mercocyanine, zwitterionic open-form) and nonpolar (spiropyran closed-form) properties of the spiropyran-merocyanine photo-chromic transformation to photomodulate surface wettability. 6-N02 BIPS (10 wt %) was added to a poly(methy 1 methacrylate) host matrix and patterned to produce reverse wettable surfaces. However, reversibility is limited to 6-8 irradiation cycles because of degradative photooxidation [22], Reverse wettable surfaces are commercially important as they may enhance drug delivery or function as a self-cleaning surface. 

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