Distinguishing cancer cells from normal cells with an organelle-targeted fluorescent marker

Identification and Drug Screening of Single Cells from Human Tumors on Semiconductor Chip for Cancer Precision Medicine

Drug screening of primary tumor cells directly assesses the drug efficacy on specific tumors, promoting personalized cancer treatment. The application of a microfluidic platform has realized drug screening using a limited amount of biopsy samples for cancer precision medicine. However, all the techniques face an inevitable issue of not all the primary tumor cells being cancer cells. Here, a system is introduced that integrates single-cell identification and drug screening on one semiconductor chip so that both drug efficacy on cancer cells and drug toxicity on noncancerous cells can be obtained simultaneously. An integrated circuit is built on the semiconductor chip for single-cell electric impedance sensing (IC-ECIS) of ultra-weak signals for distinguishing cancer cells from noncancerous cells without affecting cell vitality. Single-cell identification is validated using breast, lung, and liver cell lines as well as liver cancer specimens from clinical patients. The accuracy on commercial cell lines is ≈80%, and the diagnostic results of tumor tissues are consistent with clinical pathology results. Drug screening is run on the same chip after single cell identification for dual evaluation of drug efficacy and toxicity in both breast cancer models and clinical liver cancer patients. The on-chip drug screening is confirmed with off-chip counterpart experiments in breast cell lines. The effectiveness or ineffectiveness of a drug screened on the IC-ECIS chip demonstrated consistency in the presence or absence of specific mutations in the drug-related genes determined via exome sequencing of individual liver tumors, validating the method for precision medicine.

Fluorescence enhancement of cyanine/hemicyanine dyes with adamantane as an auxochrome through host-guest inclusion with methylated cyclodextrin in water

Fluorescence of cyanine dyes is often quenched in aqueous solution, limiting their application in water or biological system. In this work, a novel strategy of host-guest interaction based on cyanine derivatives containing auxochromes was proposed to enhance fluorescence in aqueous solution and cell imaging. By using the host (methylated β-cyclodextrin, M-β-CD) to inclusion and suppress the TICT effect of the dye, the fluorescence was significantly enhanced at lower host concentration. Cyanine and hemicyanine dyes (Ad-NH-1a, Ad-NH-1b and Ad-NH-2) with adamantyl group as auxochrome were designed and prepared by using host-guest complexation to inhibit the TICT effect of dyes, thus realizing the purpose of significantly enhancing the fluorescence of dyes at lower concentration. After adding M-β-CD, the fluorescence quantum yields of these dyes increased to 15.9 %, 21.8 %, and 6.08 %, respectively. In comparison, the fluorescence quantum yield of the dyes Ad-CONH-1 and Ad-CONH-2 containing adamantyl groups, increased only modestly from 1.78 to 2.83 times. Encouraged by these satisfactory results, further cell experiments were conducted with Ad-NH-1a, Ad-NH-1b, and Ad-NH-2. The experiment showed that adding a lower concentration of M-β-CD significantly reduced the clear imaging dosage of the probe (0.3 μM) without altering the organelle targeting of the probes.

Cucurbit[7]uril as the host of adamantane-modified dyes for fluorescence enhancement in aqueous environments

Taking advantage of the excellent host-guest complexation ability between an auxochrome (adamantane group) and CB[7], the fluorescence emission performance of dyes in water was effectively improved with the addition of two equivalents of CB[7], which provided an efficient method for increasing fluorescence intensity in aqueous environments. Furthermore, these dyes with the host were successfully used in cell imaging.

Development of Human Serum Albumin Fluorescent Probes in Detection, Imaging, and Disease Therapy

Human serum albumin (HSA) acts as a repository and transporter of substances in the blood. An abnormal concentration may indicate the occurrence of liver- and kidney-related diseases, which has attracted people to investigate the precise quantification of HSA in body fluids. Fluorescent probes can combine with HSA covalently or noncovalently to quantify HSA in urine and plasma. Moreover, probes combined with HSA can improve its photophysical properties; probe-HSA has been applied in real-time monitoring and photothermal and photodynamic therapy in vivo. This Review will introduce fluorescent probes for quantitative HSA according to the three reaction mechanisms of spatial structure, enzymatic reaction, and self-assembly and systematically introduce the application of probes combined with HSA in disease imaging and phototherapy. It will help develop multifunctional applications for HSA probes and provide assistance in the early diagnosis and treatment of diseases.

ESIPT-based fluorescent enhanced probes prompted by methylated β-cyclodextrin for the detection of thiophenols

Thiophenol and its derivatives are compounds with high toxicity to organisms and environmental pollution, so it is necessary to detect the level of thiophenols in the environment and biological samples. The probes 1a-b were obtained by introducing the 2,4-dinitrophenyl ether group into diethylcoumarin-salicylaldehyde based compounds. And they can form host-guest compounds with methylated β-cyclodextrin (M-β-CD), the association constants of inclusion complexes are 49.2 M-1, 125 M-1 respectively. The fluorescence intensities of probes 1a-b at 600 nm (1a) and 670 nm (1b) increased significantly in thiophenols detection. Meanwhile, with the addition of M-β-CD, the hydrophobic cavity of M-β-CD significantly increased the fluorescence intensity of probes 1a-b, thus the detection limits of probes 1a-b to thiophenols were reduced from 410 nM, 365 nM to 62 nM, 33 nM respectively. Whereas, the good selectivity and short response time of probes 1a-b towards thiophenols was not affected in the presence of M-β-CD. Moreover, probes 1a-b were used for further water sample detection and HeLa cell imaging experiments due to their good response to thiophenols and the results suggested that probes 1a-b had the potential to detect the content of thiophenols in water samples and living cells.

Fluorescence Enhancement of Adamantane-Modified Dyes in Aqueous Solution via Supramolecular Interaction with Methyl-β-cyclodextrin and Their Application in Cell Imaging

The fluorescence of functional dyes was generally quenched in aqueous solution, which hindered their application in water-bearing detections. In this work, a novel strategy based on host-guest interaction was provided for the purpose of fluorescence enhancement in aqueous solution and cell imaging. Three adamantane-modified fluorescent dyes (Coum-Ad, NP-Ad, NR-Ad) with coumarin, 1,8-naphthalimide and Nile Red as fluorophores were initially designed and prepared. The ((adamantan-1-yl)methyl)amino group, as the auxochrome of those dyes, complexed with methylated β-cyclodextrin (M-β-CD) via supramolecular interaction, and then fluorescent supramolecular nanoparticles (FSNPs) were formed by self-assembly in water. The inclusion equilibrium constant (K) could be as high as 3.94×104  M-1 . With the addition of M-β-CD, fluorescence quantum yields of these dyes were separately improved to 69.8 %, 32.9 % and 41.3 %. Inspired by the above satisfactory results, six adamantane-modified probes organelle-NPAds with organelle-targeting capability were further obtained. As the formation of hydrogen bonds between organelle-NPAd2 and M-β-CD verified by theoretical calculation, K of organelle-NPAd2 (5.13×104  M-1 ~4.53×105  M-1 ) with M-β-CD was higher than that of organelle-NPAd1 (1.15×104  M-1 ~3.66×104  M-1 ) and their fluorescence quantum yields increased to 32.8 %~83.6 % in aqueous solution. In addition, fluorescence enhancement was realized in cell imaging with the addition of M-β-CD.

Improved emission performance of benzo[a]phenoxazine in aqueous solution through host-guest interaction

To evaluate the contribution of host-guest chemistry in fluorescence enhancement under aqueous conditions, two benzo[a]phenoxazine derivatives with the adamantyl group were prepared. After they formed stable complexes with methyl-β-cyclodextrin, their emissions at 625-825 nm were greatly increased and fluorescence quantum yields reached 11.5-12.6% in aqueous solution. Furthermore, they were successfully applied in fluorescence labeling of organelles in HeLa cells.

Solid-state emitting twisted π-conjugate as AIE-active DSE-gen: in vitro anticancer properties against FaDu and 4T1 with biocompatibility and bioimaging

Dual-state emissive fluorogens (DSE-gens) are currently defining their importance as a transpiring tool in biological and biomedical applications. This work focuses on designing and synthesizing indole-anthracene-based solid-state emitting twisted π-conjugates using a metal-free protocol to achieve AIE-active DSE-gens, expanding their scope in biological applications. Special effort has been made to introduce proficient and photo/thermostable DSE-gens that inhibit cancer but not normal cells. Here, the lead DSE-gen initially detects cancer and normal cells by bioimaging; however, it could also confirm and distinguish cancer cells from normal cells by its abated fluorescence signal after killing cancer cells. In contrast, the fluorescence signals for a normal cell remain unscathed. Surprisingly, these molecules displayed decent anticancer properties against FaDu and 4T1 but not MCF-7 cell lines. From a series of newly designed indole-based molecules, we report one single 2,3,4-trimethoxybenzene-linked DSE-gen (the lead), exhibiting high ROS generation, less haemolysis, and less cytotoxicity than doxorubicin (DOX) for normal cells, crucial parameters for a biocompatible in vitro anticancer probe. Thus, we present a potentially applicable anticancer drug, offering a bioactive material with bioimaging efficacy and a way to detect dead cancer cells selectively. The primary mechanism behind the identified outcomes is deciphered with the support of experimental (steady-state and time-resolved fluorescence, biological assays, cellular uptake) and molecular docking studies.