| The surface chemistries of various materials (e.g., steel, nylon, and silicon) and biomolecules (e.g., protein, carbohydrates, and DNA) have been integrated to aid in macromolecular structure analysis. Platform materials were chemically modified to facilitate the isolation, manipulation, and presentation of biomolecules for analysis by laser desorption/ionization time-of-flight mass spectrometry. Three functionally distinct categories of surface modification or enhancement of mass spectrometric platforms were investigated. One class of modified platforms enabled the platform itself to bind selectively the target biomolecules directly from complex biological fluids for analysis. This process is referred to as surface-enhanced affinity capture (SEAC). The binding of targeted biomolecules was accomplished with affinity capture devices such as antibodies, ligands (e.g., chelated metal ions), and enzymes (e.g., trypsin) immobilized directly to the probe surface. In the case of enzymes, the affinity capture device also processed (e.g., enzymatic digest) the target biomolecule for structure analysis. A second functional category of modified platforms, known as surface-enhanced neat desorption (SEND), resulted from the immobilization of small organic energy-absorbing molecules on mass spectrometric platform surfaces. The SEND process enables desorption and ionization of biomolecules without assistance from any other material. Biomolecules added alone or "neat" to a SEND probe desorb intact and ionize upon laser irradiation for time-of-flight (i.e., mass) measurements. A third functional category utilized photolytic tethers on the platform surface to covalently bind biomolecules. This process referred to as surface-enhanced photolabile attachment and release (SEPAR) utilizes laser irradiation to uncouple, desorb, and ionize covalently bound target biomolecules for time-of-flight mass analysis. Different types of reactions involving the covalently bound biomolecule were performed directly in situ prior to analysis. Collectively, these surface chemistries facilitate not only biopolymer detection and structure analysis but also improve opportunities for discoveries in the fields of molecular recognition, molecular ion physics, and macromolecular desorption/ionization,... |
