ABSTRACT
Halide lead perovskite has attracted increased attention due to its excellent optical properties. However, the poor stability of the halide lead perovskite nanocrystals has been a major obstacle to their application in biosensing. Here, we proposed a method to synthesize CsPbBr3/BSA NCs perovskite using bovine serum albumin (BSA) as a zwitterion ligand. Then, a fluorescent sensor for alkaline phosphatase determination based on CsPbBr3/BSA NCs was successfully built via the interaction of L-ascorbic acid (AA) with BSA on the perovskite surface. Under optimal conditions, the sensor showed a linear concentration range from 50 to 500 µM with a detection limit of 28 µM (signal-to-noise ratio of 3) for AA, and demonstrated a linear concentration range from 40 to 500 U/L with a detection limit of 15.5 U/L (signal-to-noise ratio of 3) for alkaline phosphatase (ALP). In addition, the proposed fluorescent biosensor exhibited good selectivity and recovery in the determination of ALP in human serum. This strategy offers an innovative way for enhancing the water stability of lead halide perovskite and promoting their application in biosensing areas.
Subject(s)
Alkaline Phosphatase , Ultrasonics , Humans , Serum Albumin, Bovine , Ascorbic AcidABSTRACT
A bovine serum albumin (BSA)-assisted ultrasonication strategy was developed for the synthesis of CsPbBr3 nanocrystals (NCs) with stable fluorescence properties in aqueous solution. Such a preparation method is simple, fast and does not require complex equipment. The results show that the synthesized CsPbBr3 NCs are homogeneous in particle size and have good solubility and stability in water. The CsPbBr3 NCs have been utilized as fluorescence probe for rapid detection of hydrogen sulfide (H2S) in human serum. The reaction of H2S with the lead sites on the surface of CsPbBr3 NCs produces lead sulfide (PbS), resulting in the decrease of fluorometric intensity of CsPbBr3 NCs. Our designed fluorescent assay has a linear S2- detecting range of 10 ~ 800 nM with a detection limit of 7.05 nM. The assay was used to determine H2S in human serum with spiked recoveries ranging from 94.98% to 102.69%. This work opens new avenues for the application of halide lead perovskite in different biosensing areas.
Subject(s)
Hydrogen Sulfide , Nanoparticles , Humans , Water , Serum Albumin, Bovine , Fluorescent DyesABSTRACT
The weak fluorescence efficiency of copper nanoclusters (Cu NCs) limits their wide applications in biosensing and bioimaging areas, while the aggregation-induced emission (AIE) effect is anticipated to increase their luminescence intensity. Herein, the weak red emission of Cu NCs is increased considerably by the addition of lanthanide Tb3+, ascribed to the AIE effect. Monitoring of spores contamination can be carried out by determining the level of 2, 6-dipicolinic acid (DPA), which is a marker of spores. Due to the stronger synergy between DPA and Tb3+ for its clamped configuration of adjacent pyridine nitrogen group with the carboxylic acid group, the addition of DPA leads Tb3+ to be taken away from Cu NCs through a stronger coordination effect, causing Cu NCs to return to the dispersed state and weakened fluorescence. Based on this, an "off-on-off" fluorescent probe for DPA sensing was built, in which Tb3+ was used as a bridge to achieve AIE enhanced fluorescence effect on Cu NCs as well as a specific recognizer of DPA. The detection range for DPA was 0.1-60 µM and the detection limit was 0.06 µM, which was much lower than the infectious dose of anthrax spores. Since DPA is a unique biomarker for bacterial spores, the method was applied to the detection of actual bacterial spores and satisfactory results were obtained with a detection limit of 4.9*103 CFU mL-1.
Subject(s)
Anthrax , Humans , Anthrax/diagnosis , Copper , Picolinic Acids , BiomarkersABSTRACT
The complement system is an important part of the innate immune system, including more than 50 secretory proteins and membrane-bound proteins, and it contributes to the clearance of apoptotic cells and invading pathogens to limit inflammatory immune responses and maintaining brain homeostasis. Complement activity is strictly regulated to protect cells from random attacks or to prevent the deposition of complement proteins in physiological cases. However, overactivation or abnormal regulation of the complement cascade in the brain can lead to neuronal damage and brain dysfunction. Recent studies have pointed out that changes in complement molecules exist in patients with psychiatric diseases and play an important role in the occurrence and development of diseases by regulating the function of neurons and glial cells. Therefore, summarizing the latest research progress of complement system in psychiatric diseases such as schizophrenia, autism spectrum disorder, major depression, bipolar disorder and anxiety disorder can provide new ideas for preventing and controlling psychiatric diseases caused by abnormal activation of complement system.
Subject(s)
Autism Spectrum Disorder , Depressive Disorder, Major , Mental Disorders , Humans , Complement System Proteins , Anxiety Disorders , Membrane ProteinsABSTRACT
We presented a new benzothiazole-based fluorescent probe for ratiometric sensing of formaldehyde. Upon treatment with formaldehyde, the alkylamine-functionalized probe can be converted to its aldehyde analogue via the target-mediated 2-aza-Cope rearrangement, which led to significant shifts in both absorption (from 392 to 452 nm) and emission (from 492 to 552 nm) bands. The sensing mechanism was confirmed by HPLC, UV/Vis and fluorescence spectroscopy. The probe is capable of sensing formaldehyde under physiological conditions with high selectivity over potentially competing biological analytes. The probe also displayed sensitive ratiometric fluorescence response (up to 35.7 fold) for formaldehyde with a low limit detection of 0.58 µM. Furthermore, the probe was successfully employed for ratiometric imaging of formaldehyde in living cells as well as in zebrafish.