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Devices capable of automatically aligning cells onto geometrical arrays are of great interest to biomedical researchers. Such devices can facilitate the study of numerous cells while the cells remain physically separated from one another. In this way, cell arrays reduce cell-to-cell interactions while the cells are all subjected to common stimuli, which allows individual cell behaviour to be revealed. The use of arrays allows for the parallel analysis of single cells, facilitates data logging, and opens the door to the use of automated machine-based single cell analysis techniques. A novel permalloy based magnetic single cell micro array (MSCMA) is presented in this paper. The MSCMA creates an array of magnetic traps by generating magnetic flux density peaks at predefined locations. When using cells labelled with immunomagnetic labels, the cells will interact with the magnetic fields, and can be captured at the magnetic trap sites. Prototypes of the MSCMA have been successfully fabricated and tested using both fixed and live Jurkat cells (10 microm average diameter) that were labelled. The prototypes performed as predicted during experimental trials. The experimental results show that the MSCMA can randomly array up to 136 single cells per square mm. The results also show that the number of single cells captured is a function of the trap site density of the MSCMA design and the cell density in the fluid sample.

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The ability of bridging thiophenolate groups (RS -) to transmit magnetic exchange interactions between paramagnetic Ni(II) ions has been examined. Specific attention was paid to complexes with large Ni-SR-Ni angles. For this purpose, dinuclear [Ni2Land trinuclear [Ni3L 2 (OAc)2][BPh4]2 (3), where H2L 1 and H2L 2 represent 24-membered macrocyclic amino-thiophenol ligands, were prepared and fully characterized by IR-and UV-vis spectroscopy, X-ray crystallography, static magnetization M measurements and high-field electron spin resonance (HF-ESR). The dinuclear complex 2 has a central N3Ni2(-S)2(-OAc)Ni2N3 core with a mean Ni-S-Ni angle of 92°. The macrocycle L 2 supports a trinuclear complex 3, with distorted octahedral N2O2S2 and N2O3S coordination environments for one central and two terminal Ni(II) ions, respectively. The Ni-S-Ni angles are at 132.8° and 133.5°. We find that the variation of the bond angles has a very strong impact on the magnetic properties of the Ni complexes. In the case of the Ni2-complex, temperature T and magnetic field B dependencies of M reveal a ferromagnetic coupling J = -29 cm -1 between two Ni(II) ions (H = JS1S2). HF-ESR measurements yield a negative axial magnetic anisotropy (D < 0) which implies a bistable (easy axis) magnetic ground state. In contrast, for the Ni3-complex we find an appreciable antiferromagnetic coupling J' = 97 cm -1 between the Ni(II) ions and a positive axial magnetic anisotropy (D > 0) which implies an easy plane situation.