With the increasing importance of SQUID-based magnetically labeled immunoassay, the study on the synthesis of controllable sizes of magnetic nanoparticles plays a role to promote the accuracy of the immunoassay. In this work, Fe 3 O 4 nano-particles coated with a suitable bio-probe (biotin) are synthesized through chemical co-precipitation process to probe the bio-target (avidin). Through the synthesis developed here, the particle hydrodynamic diameter can be adjusted from 30 to 90 nm, which provide candidates for probing various bio-targets in the future. The amount of the magnetically labeled avidin is then analyzed via measuring the saturated magnetization or the remanence of the sample by using a SQUID magnetometer.

Here we report stepwise solution‐synthesis of linear nonalternant nanoribbons (NNRs), featuring pentagonal rings peri‐fused onto the repeating perylene unit. The X‐ray single‐crystal structures demonstrated their π‐backbones as a twisted ribbon, with the longest crystalline length of the nanoribbon up to 3.9 nm. NNRs exhibited an orange to deep‐red photoluminescence even under the room light, with absolute ΦF up to 82 %, most likely due to ring‐strain induced molecular stiffness. Benefiting from the enlarged size and the antiaromatic character of pentagons, all of NNRs possessed ambipolar redox properties, especially for longer nanoribbons showing multiple reversible reductions and oxidations. In addition, experimental and theoretical results indicated a ground state open‐shell singlet diradicaloid for the dication of longer NNRs. Our studies reveal the intriguing nonalternant structures and physical properties of this type of nanoribbons, involving the striking effects of the multiple annulated pentagons, and also provide fundamental insights into their electronic structures.

No abstract

When an external magnetic field is applied parallel to the film surface of a magnetic fluid film, a high-quality one-dimensional periodic chain structure is formed when the field strength reaches a certain level. With a periodic chain structure in the magnetic fluid film, an incident light is diffracted onto the magnetic thin film. The results show that the one-dimensional periodic chain structure in the magnetic fluid film can serve as an optical grating. Further investigations reveal the feasibility of developing tunable coarse wavelength-division multiplexing by utilizing a periodic chain structure.