MELDI

MELDI-MS Under 1 gg or Very high Few thousand 10,000 cells... 

Activation and equilibration of MELDI materials sample loading... 

Figure 3.10 Material-enhanced laser desorption/ionization (MELDI)-based biomarker discovery. (Courtesy of C. Huck and M. Rainer.)...

Another novel approach to utilizing affinity surfaces is referred to as the material-enhanced laser desorption/ionization (MELDI) technique [95] (Figure 3.10). This method was developed with the use of specially derivatized chromatographic materials (cellulose, silica, poly [glycidyl methacrylate/divinylbenzene] particles, and diamond powder) for fast and direct protein profiling to evaluate normal and pathological human serum samples. 

A new technique, known as material-enhanced laser desorption/ionization (MELDI), has become available for profiling proteins in complex mixtures [67], It uses derivatized carrier materials, such as cellulose, silica, poly(glycidyl methylacrylate/divinylbenzene), or diamond powder, to bind proteins from the sample. The carrier particles are derivatized with iminodiacetic acid (IDA) and loaded with ions to form [carrier-IDA-Cu +] complex, which is then added to the protein sample. The protein-bound carrier materials are spotted on the MALDI target, mixed with a MALDI matrix and analyzed by MALDI-TOF-MS. 

I. Feuerstein, et al.. Material-enhanced laser desorptionAonization (MELDI)—A new protein profiling tool utilizing specific carrier matoials for time-of-flight mass spec-trometric analysis, J. Am. Soc. Mass Spectrom. 17, 1203-1208 (2006). 

MELDI material-enhanced laser desorption/ionization... 

De Lisle RC, Meldi L, Flynn M, Jansson K (2008) Altered eicosanoid metabolism in the cystic fibrosis mouse small intestine. J Pediatr Gastroenterol Nutr 47 406-416... 

Recently it was shown that matrix-free material enhanced laser desorption/ion-ization mass spectrometry (mf-MELDI-MS) is a powerful method to study the carbohydrate compositions of medicinal plants [23]. Using this approach, common silica gel is converted into 4,4 -azodianiline modified silica, which helps to generate a significant quantity of carbohydrate ions. 

Silica gel can be derivatized in multiple ways, e.g., by covalently binding ligands via Si-O bonds to its surface. Both surface-enhanced laser desorption/ionization (SELDI) and material-enhanced laser desorption/ionization (MELDI) make use of the presence of metal complexes on a silica gel surface to selectively adsorb target compounds via conplex formation ftom solution to a target surface [197]. Besides silica gel, also cellulose or glyddyl methacrylate particles, and even diamond powder have been enployed as carriers for the metal conplex-fiinctionalized groups [198,199]. 

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