Tail Fiber Protein-Immobilized Magnetic Nanoparticle-Based Affinity Approaches for Detection of .

() strains are common nosocomial pathogens that can cause infections and can easily become resistant to antibiotics. Thus, analytical methods that can be used to rapidly identify from complex samples should be developed. Tail fiber proteins derived from the tail fibers of bacteriophages can recognize specific bacterial surface polysaccharides. For example, recombinant tail proteins, such as TF2 and TF6 derived from the tail fibers of bacteriophages ϕAB2 and ϕAB6, can recognize clinical isolates M3237 and 54149, respectively. Thus, TF2 and TF6 can be used as probes to target specific strains. Generally, TF2 and TF6 are tagged with a hexahistidine (His) for ease of purification. Given that His possesses specific affinity toward alumina through His-Al chelation, TF2- and TF6-immobilized alumina-coated magnetic nanoparticles (FeO@AlO MNPs) were generated through chelation under microwave heating (power, 900 W) for 60 s in this study. The as-prepared TF2-FeO@AlO and TF6-FeO@AlO MNPs were used as affinity probes to trap trace M3237 and 54149, respectively, from sample solutions. Matrix-assisted laser desorption/ionization mass spectrometry capable of identifying bacteria on the basis of the obtained fingerprint mass spectra of intact bacteria was used as the detection tool. Results demonstrated that the current approach can be used to distinguish M3237 from 54149 by using TF2-FeO@AlO and TF6-FeO@AlO MNPs as affinity probes. Furthermore, the limits of detection of the current method for M3237 and 54149 are ∼10 and ∼10 cells mL, respectively. The feasibility of using the developed method to selectively detect M3237 and 54149 from complex serum samples was demonstrated.