In the current research work, safranine T (ST) was chosen to be the guest, and the preparation of carbon dots (CDs) was done by a one-step hydrothermal methodology with citric acid (CA) to be the precursor, besides the surface passivation species in the consequent host–guest CDs. In addition, the CDs that had high-luminescence properties were prepared in the solid and liquid states, respectable fluorescence quantum yield of 15.2% (liquid) and 39.9% (solid), which is higher as compared with the majority of the reported orange fluorescent CDs. Meanwhile, red light-emitting diodes (LEDs) were fabricated with the use of a combination of CDs and UV LED chips. The constructed white LEDs possess excellent white light properties with the Commission Internationale de L’Eclairage chromaticity coordinate of (0.33, 0.34), coupled with the normal correlated color temperature of 5347 K as well as elevated color rendering index of 81 (>80), which seems appropriate for indoor lighting. Moreover, vitamine B12 (VB12) has the potential of productively quenching the fluorescence of CDs on the basis of the inner filter effect. Besides that, the system possessed the elevated selectivity with regard to VB12 that had the detection limit of 60.78 nM, which could further have been illustrated in not just VB12 tablets but in vitamin drink and human serum samples as well. Moreover, the CDs with the positive biocompatibility as well as ignorable cytotoxicity were extended for sensing VB12 in the living cell. These properties suggest that CDs have immense potential in the field of sensors, cell imaging, and optical devices.

Phosphopeptide enrichment with high selectivity and detection sensitivity is essential for phosphoproteomic studies and remains a long-standing challenge. In this study, new immobilized metal affinity chromatography nanocomposite adsorbents with a phosphonate-functionalized ionic liquid (PFIL) as a surface modifier are successfully prepared via a reaction sequence of amination, quaternization, phosphonate hydrolyzation, and metal immobilization. Taking advantages of integrated features of a flexible and strong tripodal phosphonate chelator, a hydrophilic ionic liquid linker, a large surface area, and the size-exclusion effect, the resulting nanocomposite G@mSiO 2 -PFIL-Ti 4+ exhibits excellent detection sensitivity to enrich phosphorylated peptides from a tryptic β-casein digest (0.15 fmol), and superior enrichment selectivity to capture phosphorylated peptides from a digest mixture of β-casein and bovine serum albumin (a molar ratio of 1:10,000). Strong immobilization of tripodal chelation to metal ions endows the nanocomposite adsorbent with high tolerance to experimental conditions, and thus excellent reusability of the adsorbent has been achieved without remarkable loss of enrichment efficiency for 10 cycles. Due to the excellent size-exclusion effect, high enrichment specificity of G@mSiO 2 -PFIL-Ti 4+ to phosphopeptides has been observed and 23 endogenous phosphopeptides have been captured from human saliva. In addition, 924 phosphopeptides (enrichment specificity, 56.1%) have been identified from the tryptic digest of mouse brain lysate. Particularly, six of 975 phosphorylation sites were Alzheimer's disease-related hyperphosphorylation sites within tau protein. These results demonstrate that G@mSiO 2 -PFIL-Ti 4+ nanocomposite affinity materials show great application potential for a proteomic study of complicated biological samples.

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An electrochemical aptasensor for the ultrasensitive determination of TB based on sandwich-type structure-triggered signal amplification.