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Magnetic nanoreagents (MNRs), consisting of liquid solutions and magnetic nanoparticles (MNPs) coated with bioprobes, have been widely used in biomedical disciplines. For in vitro tests of serum biomarkers, numerous MNR-based magnetic immunoassay methods or schemes have been developed; however, their applications are limited. In this study, a vibrating sample magnetometer (VSM) was used for screening tumor biomarkers based on the same MNRs as those used in other immunoassay methods. The examination mechanism is that examined tumor biomarkers are typically conjugated to the bioprobes coated on MNPs to form magnetic clusters. Consequently, the sub-Tesla-field magnetization (Msub-T) of MNRs, including magnetic clusters, exceeds that of MNRs containing only separate MNPs. For human serum samples, proteins other than the targeted biomarkers induce the formation of magnetic clusters with increased Msub-T because of weak nonspecific binding. In this study, this interference problem was suppressed by the vibratio...

Single-crystalline CaMn3O6 nanoribbons have been synthesized by a molten-salt method. To explore the origin of the magnetism of nanosized antiferromagnetic (AFM) manganites, a comparative study has been conducted for CaMn3O6 (CMO-1) and post-growth vacuum annealed (CMO-2) nanoribbons. A lattice expansion resulting from oxygen release during vacuum annealing is observed. Correspondingly, AFM ordering in CMO-2 is further suppressed, and ferromagnetism and spin-glass (SG)-like behavior are significantly enhanced, which are presumed attributable to the intrinsic structural distortions induced by oxygen vacancies. In this case, side and surface effects are not decisive factors. In addition, this study provided observations of the exchange bias effect in manganite nanoribbons with an AFM-SG-like-ferromagnetic (FM) structure, as compared with the typical AFM-core-FM-shell.

In this paper, we report an enhanced liver tumor discrimination for rats using antibody-activated magnetic nanoparticles (MNs) and ultra-low-field magnetic resonance imaging ex vivo. It was found that the intensity ratio between the magnetic resonance image of tumor and normal liver tissues is 2–3 absence of antibody-activated MNs in rats. The intensity ratio rises to ∼100 when antibody-activated MNs are expressed in liver tumors through vein injection. Enhancing tumor discrimination using antibody-activated MNs is demonstrated using T1-weighted contrast imaging in ultra-low magnetic fields.

The characterization of cancerous livers in rats using nuclear magnetic resonance and magnetic resonance imaging (NMR/MRI) based on high-Tc superconducting quantum interference devices (SQUIDs) is presented. The T1−1 were observed to be 6.5±0.5 s−1 for controlled livers and 2.85±0.2 s−1 for cancerous livers, which indicate that the T1 can be used to distinguish the cancerous tissues from controlled liver tissues. The intensity ratio for tap water, cancerous tissue, and controlled tissue, respectively, is 1:1.15:0.56 at TBp=1 s. The SQUID-detected NMR/MRI exhibits potential applications in research and clinics.