A novel water-soluble AIE-based fluorescence probe with red emission for the sensitive detection of heparin in aqueous solution and human serum samples

Aggregation-Induced Emission Luminogen: Role in Biopsy for Precision Medicine

Biopsy, including tissue and liquid biopsy, offers comprehensive and real-time physiological and pathological information for disease detection, diagnosis, and monitoring. Fluorescent probes are frequently selected to obtain adequate information on pathological processes in a rapid and minimally invasive manner based on their advantages for biopsy. However, conventional fluorescent probes have been found to show aggregation-caused quenching (ACQ) properties, impeding greater progresses in this area. Since the discovery of aggregation-induced emission luminogen (AIEgen) have promoted rapid advancements in molecular bionanomaterials owing to their unique properties, including high quantum yield (QY) and signal-to-noise ratio (SNR), etc. This review seeks to present the latest advances in AIEgen-based biofluorescent probes for biopsy in real or artificial samples, and also the key properties of these AIE probes. This review is divided into: (i) tissue biopsy based on smart AIEgens, (ii) blood sample biopsy based on smart AIEgens, (iii) urine sample biopsy based on smart AIEgens, (iv) saliva sample biopsy based on smart AIEgens, (v) biopsy of other liquid samples based on smart AIEgens, and (vi) perspectives and conclusion. This review could provide additional guidance to motivate interest and bolster more innovative ideas for further exploring the applications of various smart AIEgens in precision medicine.

Recent advances in sugar-based AIE luminogens and their applications in sensing and imaging

Most fluorogens with aggregation-induced emission (AIE) characteristics are hydrophobic and most common sugars are hydrophilic and naturally nontoxic. The combination of AIEgens and sugars can construct glycosyl AIEgens with the advantages of good water-solubility, low fluorescent background and satisfactory biocompatibility. Based on the specific reaction or binding with analytes to change the conjugate system or restrict intramolecular motions, glycosyl AIEgens can be used as powerful tools for detecting bioactive molecules or imaging living cells. In this feature article, we summarize recent advances in sugar-based AIE luminogens and their applications in biosensing and imaging. The sugar units could significantly increase the solubility, biocompatibility, target activity, and chemical modifying capacity and often decrease the background fluorescence of the AIE probes. Corresponding studies not only expand the application fields of AIEgens but also provide effective tools for broad carbohydrate research.

A novel dual-function fluorescent probe for the detection of cysteine and its applications in vitro

A fluorescent probe of both colorimetric and ratiometric type for highly selective and sensitive detection of Cys (cysteine) is very important in biological analysis. In this work, a new colorimetric and ratiometric fluorescent probe ((E)-2-(2-(5-(4-(acryloyloxy)phenyl)furan-2-yl)vinyl)-3-methylbenzo[d]thiazol-3-ium iodide, LP-1) was designed and synthesized for the detection of Cys. The reaction mechanism of LP-1 toward Cys involves a conjugate addition reaction between Cys and the α,β-unsaturated carbonyl group, leading to the formation of an intermediate thioether, followed by intramolecular cyclization to produce the desired compounds LP-1-OH. At this point, the ICT process is activated, significantly increasing the fluorescence intensity of the molecules. Meanwhile, LP-1 is highly selective and sensitive to Cys identification under optimized experimental conditions. LP-1 shows a good linear relationship in the range of Cys concentration from 0.40 μM to 40 μM (R2 = 0.9942) and the limit of detection (LOD) of Cys is 0.19 μM. In addition, we have developed a simple, portable and low-cost smartphone-based high-sensitivity Cys detection method based on naked eye obvious color detection. LP-1 also has low cell toxicity and can be successfully used for biological imaging of Cys, suggesting that it is a promising biological application tool for Cys detection.

Construction of a highly sensitive detection platform for heparin based on a "turn-off" cationic fluorescent dye

A highly sensitive detection platform for heparin was constructed via the utilization of a commercially available cationic fluorescent dye (cresyl violet acetate, CV) as a fluorescence probe. The electrostatic binding between CV and heparin quenched the fluorescence in 4-(2-hydroxyethyl)-1-piperazineethanesulfonic (HEPES) buffer solution (10 mM, pH 7.1). CV was highly selective towards heparin over other potential inferring substances. The detection limit of heparin detection was 5.19 ng/mL, and the linear working range was 0 ∼ 1 μg/mL in HEPES solution. In 1 % serum, the detection platform based on the fluorescence "turn-off" behavior of CV was also successfully constructed with a detection limit of 5.86 ng/mL in the linear range of 0 ∼ 0.8 μg/mL. Moreover, the CV-heparin complex was considered a potential sensor platform for the detection of protamine because of its stronger affinity for heparin and protamine.

A novel near-infrared fluorescent probe based on triphenylamine derivatives for the rapid and sensitive detection of heparin

In this study, a positively charged near-infrared fluorescent probe (TPA-P+) was constructed by connecting a pyridine cation with triphenylamine and successfully used for the detection of heparin.

Chemical sensors for selective and quantitative heparin sensing

In this review article, chemical sensors for selective and quantitative heparin sensing are discussed with detailed examples.

Lost in (Clinical) Translation: Recent Advances in Heparin Neutralization and Monitoring

The heparin family, which includes unfractionated heparin, low-molecular heparin, and fondaparinux, is a class of drugs clinically used as intravenous blood thinners. To date, issues related to both the reversal of anticoagulation and the blood level determination of the anticoagulant at the point-of-care remain: while the only U.S. Food and Drug Administration (FDA) approved antidote for heparin displays serious efficacy and safety drawbacks, the current assays for heparin monitoring are indirect measurements subject to their own limitations and variations. Herein, we provide an update on the numerous recent chemical approaches to tackle these issues, from which it is clear that some new antidotes and sensors for heparin certainly have the potential to exceed current clinical standards. This review aims to review a field that requires close collaborations between physicians, biologists, and chemists in order to foster advances toward clinical translation.

Progress and Trends in AIE-Based Bioprobes: A Brief Overview

Luminescent bioprobes are powerful analytical means for biosensing and optical imaging. Luminogens featured with aggregation-induced emission (AIE) attributes have emerged as ideal building blocks for high-performance bioprobes. Bioprobes constructed with AIE luminogens have been identified to be a novel class of FL light-up probing tools. In contrast to conventional bioprobes based on the luminophores with aggregation-caused quenching (ACQ) effect, the AIE-based bioprobes enjoy diverse superiorities, such as lower background, higher signal-to-noise ratio and sensitivity, better accuracy, and more outstanding resistance to photobleaching. AIE-based bioprobes have been tailored for a vast variety of purposes ranging from biospecies sensing to bioimaging to theranostics (i.e., image-guided therapies). In this review, recent five years' advances in AIE-based bioprobes are briefly overviewed in a perspective distinct from other reviews, focusing on the most appealing trends and progresses in this flourishing research field. There are altogether 11 trends outlined, which have been classified into four aspects: the probe composition and form (bioconjugtes, nanoprobes), the output signal of probe (far-red/near-infrared luminescence, two/three-photon excited fluorescence, phosphorescence), the modality and functionality of probing system (dual-modality, dual/multifunctionality), the probing object and application outlet (specific organelles, cancer cells, bacteria, real samples). Typical examples of each trend are presented and specifically demonstrated. Some important prospects and challenges are pointed out as well in the hope of intriguing more interests from researchers working in diverse areas into this exciting research field.