Amine response smartphone-based portable and intelligent polyvinyl alcohol films for real-time detection of shrimp freshness.

Food freshness monitoring is an important component in ensuring food safety for consumers and the food industry. Therefore, there is an urgent need for a portable, low-cost, and efficient detection method to determine the freshness. In this study, polyvinyl alcohol (PVA) was used as polymer carrier to prepare electrospinning film containing curcumin (Cur) and gardenia blue (GB) as intelligent indicator label on food packaging for real-time nondestructive detection of freshness of shrimp. The detection limit of ammonia response is less than or equal to 20 ppm, and the detection time is about 1 min, indicating that it has a sensitive response effect. At the same time, a smartphone application that can identify amines in response to color changes has been developed, and consumers can understand freshness by scanning the label. This study demonstrates the huge potential of smart indicator labels for food freshness monitoring.

Developing a Two-Photon "AND" Logic Probe and Its Application in Alzheimer's Disease Differentiation.

In Alzheimer's disease, hypochlorous acid involved in the clearance of invading bacteria or pathogens and butyrylcholinesterase engaged in the hydrolysis of the neurotransmitter acetylcholine are relatively significantly altered. However, there are few dual detection probes for hypochlorous acid and butyrylcholinesterase. In addition, single-response probes suffer from serious off-target effects and near-infrared probes do not easily penetrate the blood-brain barrier due to their excessive molecular weight. In this work, we constructed a two-photon fluorescent probe that recognizes hypochlorous acid and butyrylcholinesterase based on a dual-lock strategy. The thiocarbonyl group is oxidized in the presence of hypochlorous acid, and the hydrolysis occurs at the 7-position ester bond in the existence of butyrylcholinesterase, releasing a strongly fluorescent fluorophore, 4-methylumbelliferone. Excellent imaging was performed in PC12 cells using this probe, and deep two-photon imaging was observed in the brains of AD mice after tail vein injection with this probe. It indicates that the probe can provide a promising tool for the more precise diagnosis of Alzheimer's disease.

Hypochlorite activatable ratiometric fluorescent probe based on endoplasmic reticulum stress for imaging of atherosclerosis.

Endoplasmic reticulum (ER) stress can induce reactive oxygen (ROS) generation which is directly associated with the emergence of atherosclerosis. Foam cells could promote atherogenesis by inducing ER stress. To understand hypochlorite (ClO-) levels in foam cells under ER stress, novel ER-targeted ClO- activatable ratiometric fluorescence probes Rx-NE and Rx-NCE were designed using a classical rhodamine dye and coumarin dye bridge moiety as the fluorescent skeleton. Both Rx-NE and Rx-NCE demonstrated ratiometric detection capabilities for ClO-, with Rx-NCE showing better sensitivity compared to Rx-NE. The probe Rx-NCE could detect the upregulation of ClO- in foam cells under ER stress and clearly outline delineation of the boundary of atherosclerotic plaques by dual-color imaging. Importantly, the hypochlorite-activated ratiometric probe Rx-NCE had been innovatively applied to the distinction of atherosclerotic blood vessels in atherosclerosis-bearing transgenic (tg) (flk1: eGFP) zebrafish. The probe Rx-NCE is of significant value for investigating the pathological role of ER stress and atherosclerotic diseases, as well as offering new insights into the identification of atherosclerosis.

Diagnosing Orthotopic Lung Tumor Using a NTR-Activatable Near-Infrared Fluorescent Probe by Tracheal Inhalation.

Nitroreductase (NTR) is an enzyme that is upregulated under tumor-depleted oxygen conditions. The majority of studies have been conducted on NTR, but many existing fluorescent imaging tools for monitoring NTR inevitably suffer from weak targeting, low sensitivity, and simple tumor models. Research on diagnosing lung tumors has been very popular in recent years, but targeting assays in orthotopic lung tumors is still of great research value, as such models better mimic the reality of cancer in the organism. Here, we developed a novel near-infrared (NIR) fluorescent probe IR-ABS that jointly targets NTR and carbonic anhydrase IX (CAIX). IR-ABS has excellent sensitivity and selectivity and shows exceptional NTR response in spectroscopic tests. The measurements ensured that this probe has good biosafety in both cells and mice. A better NTR response was found in hypoxic tumor cells at the cellular level, distinguishing tumor cells from normal cells. In vivo experiments demonstrated that IR-ABS achieves a hypoxic response at the zebrafish level and enables rapid and accurate tumor margin distinguishment in different mouse tumor models. More importantly, we successfully applied IR-ABS for NTR detection in orthotopic lung tumor models, further combined with tracheal inhalation drug delivery to improve targeting. To the best of our knowledge, we present for the first time a near-infrared imaging method for targeting lung cancerous tumor in situ via tracheal inhalation drug delivery, in contrast to the reported literature. This NIR fluorescence diagnostic strategy for targeting orthotopic lung cancer holds exciting potential for clinical aid in cancer diagnosis.

ß-Lactamase-Responsive Probe for Efficient Photodynamic Therapy of Drug-Resistant Bacterial Infection.

Several photosensitizers have recently been proposed as novel approaches against ß-lactamase-producing drug-resistant bacteria. However, these reported photosensitizers are rarely used for accurate recognition of drug-resistant bacteria. To tackle this challenge, the structurally modified photosensitizer CySG-2 based on a lipophilic cationic heptamethine indocyanine near-infrared (NIR) dye (IR-780) and an important synthesis intermediate of cephalosporin antibiotic (GCLE) not only achieved the accurate recognition of TEM-1 methicillin-resistant Staphylococcus aureus (MRSA) successfully but also achieved antimicrobial photodynamic therapy (aPDT) in animal models infected by drug-resistant bacteria. Accurate enzyme recognition and efficient photodynamic therapy capabilities allow CySG-2 to achieve one stone with two birds. In addition, CySG-2 could also promote the eradication of internalized MRSA by facilitating the autophagy process, which is synergistic with its capacity of inducing reactive oxygen species generation under NIR laser irradiation for aPDT. Collectively, it is an effective multifunctional photosensitizer with the potential ability to guide the optimal use of different antibiotics and apply them in clinical treatment.

An automatic method for counting wheat tiller number in the field with terrestrial LiDAR.

BACKGROUND: The tiller number per unit area is one of the main agronomic components in determining yield. A real-time assessment of this trait could contribute to monitoring the growth of wheat populations or as a primary phenotyping indicator for the screening of cultivars for crop breeding. However, determining tiller number has been conventionally dependent on tedious and labor-intensive manual counting. In this study, an automatic tiller-counting algorithm was developed to estimate the tiller density under field conditions based on terrestrial laser scanning (TLS) data. The novel algorithm, which is named ALHC, involves two steps: (1) the use of an adaptive layering (AL) algorithm for cluster segmentation and (2) the use of a hierarchical clustering (HC) algorithm for tiller detection among the clusters. Three field trials during the 2016-2018 wheat seasons were conducted to validate the algorithm with twenty different wheat cultivars, three nitrogen levels, and two planting densities at two ecological sites (Rugao & Xuzhou) in Jiangsu Province, China. RESULT: The results demonstrated that the algorithm was promising across different cultivars, years, growth stages, planting densities, and ecological sites. The tests from Rugao and Xuzhou in 2016-2017 and Rugao in 2017-2018 showed that the algorithm estimated the tiller number of the wheat with regression coefficient (R2) values of 0.61, 0.56 and 0.65, respectively. In short, tiller counting with the ALHC generally underestimated the tiller number and performed better for the data with lower plant densities, compact plant types and the jointing stage, which were associated with overlap and noise between plants and inside the dense canopy. CONCLUSIONS: Differing from the previous methods, the ALHC proposed in this paper made full use of 3D crop information and developed an automatic tiller counting method that is suitable for the field environment.

Design and synthesis of NQO1 responsive fluorescence probe and its application in bio-imaging for cancer diagnosis.

As an over-expressed flavoprotein in several kinds of tumor cells, NAD(P)H: quinone oxidoreductase-1 (NQO1) is considered as a potent biomarker in early-stage cancer diagnosis. Developing a fast, selective and sensitive method of monitoring NQO1 on cellular level will greatly promote cancer diagnosis in clinical practice. In this paper, a fast NQO1 responsive fluorescence probe SYZ-30 containing quinone acid and 7-nitro-2,1,3-benzoxadiazole (NBD) fluorophore is constructed. The probe could selectively respond to NQO1 and rapidly emit strong fluorescence in vitro within only 5 min. Notably, the peak fluorescent intensities at 550 nm showed a linear relationship with NQO1 concentrations in the range of 3-30 ng/ml and limit of detection (LOD) was 0.0667 ng/ml. Furthermore, it was validated that the probe has good biocompatibility and could be applied for bio-imaging in NQO1 over-expressed cancer cells, together with its mitochondria targeting ability. Importantly, confocal fluorescence imaging confirmed the NQO1 detection ability on cellular level, which can be used for real-time detection of several cancer subtypes like adenocarcinoma. To conclude, the probe is rapidly responsive, highly sensitive and selective which will potentially become a practical tool for early cancer detection and diagnosis.

Thermosensitive drug-loading system based on copper sulfide nanoparticles for combined photothermal therapy and chemotherapy in vivo.

A phase-change material (PCM) is an efficient energy storage material, but its poor thermal conductivity has limited its application in nanomedicine research. In this study, we used the photothermal material copper sulfide (CuS) to tackle this challenge. The designed CuS-DOX-MBA@PCM nanoparticles (NPs) were prepared by a nanoprecipitation method, and were composed of CuS, the anticancer drug (DOX), and near-infrared (NIR) dyes (MBA) encapsulated with stearic acid and lauric acid, which are characterized by a low eutectic point close to human physiological temperature. Because the CuS-DOX-MBA@PCM NPs could release the drug quickly in physiological conditions, it implied that they could have potential as a promising drug-loading system. CuS-DOX-MBA@PCM NPs were utilized as an imaging-guided photothermal agent for photothermal therapy (PTT) combined with chemotherapy in cells and in a mice model. In vitro fluorescence imaging indicated the high uptake of CuS-DOX-MBA@PCM NPs in tumor cells due to enhanced permeability and retention effects, while in vivo experiments showed that the tumor growth in tumor-bearing mice models could be inhibited by the CuS-DOX-MBA@PCM NPs. Such an evident enhanced tumor inhibition could be attributed to the synergistic effect of the DOX chemotherapy and the photothermal therapy with a safe laser irradiation at 808 nm with a power density of 1.0 W cm-2. Furthermore, this combined therapy offers the possibility to lower the dosage of DOX in anticancer therapy, which would thus decrease the toxic effects on cancer patients. The results from this study confirmed the effect of CuS-DOX-MBA@PCM NPs for use as a chemo-photothermal therapy and the clinical value of the designed thermosensitive drug-loading system in the field of combined cancer therapy.

Correction: A tumor-targeting probe based on a mitophagy process for live imaging.

Correction for 'A tumor-targeting probe based on a mitophagy process for live imaging' by Lijuan Gui et al., Chem. Commun., 2018, 54, 9675-9678.

The potential of biomimetic nanoparticles for tumor-targeted drug delivery.

In past decades, rapid progress in nanoparticle (NP) synthesis and engineering has provided a broad range of nanoscale agents affording both therapeutic and diagnostic functions. More recently, the emergence of biomimetic NPs as an efficient and promising technology has further expanded this field. The employment of biomemetic NPs offers many distinct advantages, including enhanced stability, the solubilization of hydrophobic payloads, extended blood residence times and the ability to better target a region of interest. In this review, we focus on two main categories of biomimetic NPs, protein/peptide-templated biomimetic NPs and cell membrane-derived biomimetic NPs. The properties, applications and challenges of these biomimetic NPs in tumor diagnosis and treatment are discussed. The pros and cons, and future development, of biomimetic NPs are also considered.

GSH-Activated Light-Up Near-Infrared Fluorescent Probe with High Affinity to αvß3 Integrin for Precise Early Tumor Identification.

The development of tumor-associated, stimuli-driven, turn-on near-infrared (NIR) fluorophores requires urgent attention because of their potential in selective and precise tumor diagnosis. Herein, we describe a NIR fluorescent probe (CyA-cRGD) comprised of a fluorescence reporting unit (a cyanine dye) linked with a GSH-responsive unit (nitroazo aryl ether group) and a tumor-targeting unit (cRGD). The NIR fluorescence of CyA-cRGD with sensitive and selective response to GSH can act as a direct off-on signal reporter for GSH monitoring. Notably, CyA-cRGD possesses improved biocompatibility compared with CyA, which is highly desirable for in vivo fluorescence tracking of cancer. Confocal fluorescence imaging confirmed the tumor-targeting capability and GSH detection ability of CyA-cRGD in tumor cells, normal cells, and coincubated tumor /normal cells and in the three-dimensional multicellular tumor spheroid. Furthermore, it was validated that CyA-cRGD could detect tumor precisely in GSH and integrin αvß 3 high-expressed tumor-bearing mouse models. Importantly, it was confirmed that CyA-cRGD possessed high efficiency for early-stage tumor imaging in mouse models with tumor cells implanted within 72 h. This method provided significant advances toward more in-depth understanding and exploration of tumor imaging, which may potentially be applied for clinical early tumor diagnosis.

A tumor-targeting probe based on a mitophagy process for live imaging.

A glucosamine modified near-infrared cyanine dye CyT sensitive to pH was synthesized. Due to the different pH values of mitochondria and autolysosomes, the probe can simultaneously investigate mitochondria and autolysosomes in living cells. Moreover, due to the introduction of glucosamine groups, this fluorescent probe can be applied for tumor targeted imaging.

Methionine-Decorated Near Infrared Fluorescent Probe for Prolonged Tumor Imaging.

Methionine (Met) is one of the essential amino acids of which the transport system L is overexpressed in various tumor cells. In this study, a near-infrared fluorescent dye (IR-780) and methionine were conjugated through a piperazin-polyamines linker to form Cy-Met. The successful synthesis of Cy-Met was validated by optical characterization, NMR, and MS spectra. The absorption peak of Cy-Met was at 680 nm, and the fluorescence peak was at 790 nm. The cytotoxicity assay and cell imaging studies indicated that Cy-Met had good biocompatibility and specific affinity to tumor cells. The dynamic distribution and clearance investigations showed that Cy-Met was eliminated by the liver-intestine pathway. Notably, Cy-Met displayed tumor-targeting ability in U87, H22, and EAC tumor-bearing mice with an evident long circulation time. The results implied that Cy-Met could act as a promising fluorescence probe specialized for long-term tumor monitoring.

Near infrared dye loaded copper sulfide-apoferritin for tumor imaging and photothermal therapy.

Development of photothermal agents for imaging-guided photothermal therapy (PTT) has been of great interest in the field of nanomedicine. CuS-apoferritin was prepared by a biomimetic synthesis method by using the inside cavity of apoferritin to control the size of CuS nanoparticles. Then, a water-soluble near infrared (NIR) dye (MBA) was bound with CuS-apoferritin, forming a nanocomplex (CuS-apoferritin-MBA) with greatly enhanced photothermal conversion efficiency compared to CuS-apoferritin. The unique optical behavior of CuS-apoferritin-MBA enables fluorescence imaging and photothermal therapy at separated optical wavelengths both, with optimized performances. CuS-apoferritin-MBA was then utilized as a photothermal agent for imaging-guided photothermal therapy in tumor-bearing mouse models. As revealed by in vivo fluorescence imaging, CuS-apoferritin-MBA showed high tumor uptake owing to an enhanced permeability and retention effect and the active targeting of apoferritin. In vivo photothermal therapy experiments indicated that tumors could be ablated by combining CuS-apoferritin-MBA with irradiation of an 808 nm laser. Thus, our work presents a safe, simple photothermal nanocomplex, promising for future clinical translation in cancer treatment.

Mapping heterotic loci for yield and agronomic traits using chromosome segment introgression lines in cotton.

In the present study, a set of chromosome segment introgression lines (CSILs) using Gossypium hirsutum L. TM-1 as the recipient parent and G. barbadense Hai7124 as the donor parent were used to explore the genetic basis of heterosis for interspecific hybrids. Two sets of F1 populations individually derived from CSILs crossing with both parents were configured to investigate heterotic loci (HL) and substitution effect loci (SL). A total of 58 HL and 39 SL were identified in 3 years. One stable HL, hLP-A4-3, could be detected in all 3 years. Three HLs, hBS-A8-1, hLP-D6-1, and hSI-D7-11, could be detected in 2 years. Four SLs, sBS-D7-1, sLP-A8-1, sLP-D7-1, and sLP-D12-1, could be detected in 2 years. HL and SL tended to be distributed in some HL-rich chromosome segments with close positions. Compared with QTL detected in a former study, HL showed little overlap with QTL, indicating that trait phenotype and heterosis might be controlled by different sets of loci. All three forms of genetic effects (partial-, full-, over-dominant) were identified, while the over-dominant effect made the main contribution to heterosis. These results may help lay the foundation for clarifying the heredity mechanism of heterosis in cotton.

[Realization of short cut nitrification under the limited filamentous sludge bulking condition].

In order to realize the combination of "low oxygen limited filamentous sludge bulking" and short cut nitrification,the startup method of short cut nitrification and the maintenance strategies of sludge settleability were investigated under limited filamentous sludge bulking condition by using sequencing batch reactor (SBR). The effects of environmental factors like water quality, pH, DO,temperature and operation methods like mixture flow pattern, aeration mode, influent pattern on sludge settleability were analyzed. The results show that, when pH is between 7.2 and 8.0 and temperature is between 20 degrees C and 25 degrees C, short cut nitrification can be gradually realized through maintaining low DO and controlling the aeration time accurately. Nitrite accumulating ratio can increase from 28% to 80% after operating 160 cycles. Sludge settleability can be maintained effectively by changing the influent volume exchanging ratio (VER) assisted by aeration rate .The sludge volume index (SVI) can be maintained around 150 mL/g by adjusting the VER from 0.25 to 0.33 under limited sludge bulking. At the end of the aerobic phase, dissolved total nitrogen concentration increase slightly.