In the past few years, protein biochips have emerged as promising proteomic and diagnostic tools for obtaininginformation
about protein functions and interactions. Important technological innovations have been made. However,considerable development is still required, especially regarding protein
immobilization, in order to fully realizethe potential of protein biochips. In fact, protein immobilization is the key to the success of microarray
technology.Proteins need to be immobilized onto surfaces with high density in order to allow the usage of small amount ofsample solution. Nonspecific protein adsorption needs to be avoided or at least minimized in order to improvedetection performances. Moreover, full retention of protein conformation and activity is a challenging task to beaccomplished. Although a large number of review papers on protein biochips have been published in recentyears, few have focused on protein immobilization technology. In this review, current protein immobilizationstrategies, including physical, covalent, and bioaffinity immobilization for the fabrication of protein biochips, aredescribed. Particular consideration has been given to oriented immobilization, also referred to as site-specificimmobilization, which is believed will improve homogeneous surface covering and accessibility of the activesite.