Fluorescent signal-based lateral flow immunochromatographic strips (FLFICS) have received great expectations since they combine the quantitative sensitivity of fluorescence analysis and the simplicity, rapidness, and portability of a common lateral flow immunochromatographic strip (LFICS).

Functionalized quantum dots (QDs) have been widely explored for multimodality bioimaging and proven to be versatile agents. Attaching positron-emitting radioisotopes onto QDs not only endows their positron emission tomography (PET) functionality, but also results in self-illuminating QDs, with no need for an external light source, by Cerenkov resonance energy transfer (CRET). Traditional chelation methods have been used to incorporate the radionuclide, but these methods are compromised by the potential for loss of radionuclide due to cleavage of the linker between particle and chelator, decomplexation of the metal, and possible altered pharmacokinetics of nanomaterials. Herein, we described a straightforward synthesis of intrinsically radioactive [⁶⁴Cu]CuInS/ZnS QDs by directly incorporating ⁶⁴Cu into CuInS/ZnS nanostructure with ⁶⁴CuCl₂ as synthesis precursor. The [⁶⁴Cu]CuInS/ZnS QDs demonstrated excellent radiochemical stability with less than 3% free ⁶⁴Cu detected even after exposure to serum containing EDTA (5 mM) for 24 h. PEGylation can be achieved in situ during synthesis, and the PEGylated radioactive QDs showed high tumor uptake (10.8% ID/g) in a U87MG mouse xenograft model. CRET efficiency was studied as a function of concentration and ⁶⁴Cu radioactivity concentration. These [⁶⁴Cu]CuInS/ZnS QDs were successfully applied as an efficient PET/self-illuminating luminescence in vivo imaging agents.

Currently, protein/peptide-based biomimetic mineralization has been demonstrated to be an efficient and promising strategy for synthesis of inorganic/metal nanoparticles (NPs) for bioapplications. This strategy is found to be bio-inspired, straightforward, and environmentally benign. It can produce inorganic/metal NPs with good stability, excellent biocompatibility, high water solubility, and rich surface functional groups for further bioconjunction. In this review, we provide a summary of the previously reported proteins/peptides as biotemplates involved in biomimetic mineralization synthesis, and categorize the obtained inorganic NPs ranging from metal nanoclusters (MNCs), quantum dots (QDs), gadolinium derivatives, and metal sulfide nanoparticles (MSNPs) with an emphasis on the recent progress in their use in biomedical applications, including bio-sensing, ion detection, bio-labeling, in vivo imaging and therapy. In the end, the challenges and future outlook in this emerging area are also discussed.