The abnormal metabolic activity of the tumor can increase the oxygen consumption in tumor cells,and the poor blood perfusion often happens in tumor regions as well,which are the main reasons that result in a hypoxic s...The abnormal metabolic activity of the tumor can increase the oxygen consumption in tumor cells,and the poor blood perfusion often happens in tumor regions as well,which are the main reasons that result in a hypoxic situation in the tumor.A fluorescence probe,AQD,with selective response toward hypoxia was designed for the detection of hypoxic tumor cells,which was obtained by the covalent connection of a large planar conjugated fluorophore with good fluorescence stability and a N,N-dimethylaniline moiety via the azo bond.The introduction of the azo bond in AQD caused significant fluorescence emission quenching,and the probe was reduced under hypoxic conditions to release the fluorophore via breaking the azo bond,resulting in the gradual recovery of fluorescence emission.Probe AQD exhibited a remarkable fluorescence response in hypoxic conditions,high selectivity,and good biocompatibility,which was successfully used for the imaging of hypoxic tumor cells and realized the detection of hypoxic A549 cells.展开更多
Somatic cell count detection is the daily work of dairy farms to monitor the health of cows.The feasibility of applying near-infrared spectroscopy to somatic cell count detection was researched in this paper.Milk samp...Somatic cell count detection is the daily work of dairy farms to monitor the health of cows.The feasibility of applying near-infrared spectroscopy to somatic cell count detection was researched in this paper.Milk samples with different somatic cell counts were collected and preprocessing methods were studied.Variable selection algorithm based on hybrid strategy and modelling method based on ensemble learning were explored for somatic cell count detection.Detection model was used to diagnose subclinical mastitis and the results showed that near-infrared spectroscopy could be a tool to realize rapid detection of somatic cell count in milk.展开更多
As a new form of fluorescent carbon nanomaterials, carbon dots （CDs） have many advantages such as simplicity of synthesis, low biological toxicity, resistance to photobleaching, excellent in biocompatibility and eas...As a new form of fluorescent carbon nanomaterials, carbon dots （CDs） have many advantages such as simplicity of synthesis, low biological toxicity, resistance to photobleaching, excellent in biocompatibility and easy to modify. As the most inorganic mineral of human hard tissues including bone and tooth, calcium phosphate （CaP） materials have high biocompatibility and good biodegradability. The hydroxyapatite （HA）, a common type of calcium phosphate, has been widely used in drug delivery, removal of heavy metal ions, gene transfection and other biomedical fields. Herein, a novel method for preparation of fluorescent calcium phosphate/carbon dot （ CaP/ CD） hybrid composites was described. We first prepared CDs with a quantum yield of 51.5 % by carbonization of citric acid with polyethylenimine （PEI） in one step. Next, the fluorescent CaP/CD hybrid composites upon UV ex- citation were obtained in the presence of carboxymethyl cellulose （CMC） as a template and CD as a co-template. The as-prepared CaP/CD hybrid composites consisted of irregularly shaped nanorods with a length of 50 - 140 nm and a diameter of 10- 25 nm were characterized by transmitted electron microscopy （TEM）. And the highly mag- nified TEM image of CaP/CD hybrid composites showed that tens of CDs in shape of nanodot indeed existed in the CaP/CD hybrid composites. More importantly, CDs enabled the CaP/CD hybrid composites to emit bright blue flu- orescence under UV irradiation. In addition, the result of X-ray powder diffraction （XRD） patterns indicated that the crystalline phase of CaP/CD hybrid composites were in good agreement with those of hexagonal HA （JCPDS Da- ta Card 09-0432）. Moreover, it was found that the as-synthesized CaP/CD hybrid composites were potentially use- ful in detecting the concentration of Cu2＋ and imaging the cell with nontoxic as potential fluorescent probes.展开更多
When the loop-mediated isothermal amplification(LAMP)assay is used for detecting target genes,DNA extraction is unnecessary in many cases.Simple pretreatment(e.g.heating)is enough to obtain rather sensitive responses....When the loop-mediated isothermal amplification(LAMP)assay is used for detecting target genes,DNA extraction is unnecessary in many cases.Simple pretreatment(e.g.heating)is enough to obtain rather sensitive responses.Even test samples without any pretreatment can be used as template.This feature suggests that LAMP is superior to PCR in developing point-of-care test strategies.In this study,using Stx1 gene from E.coli as model,we verified that viable cells,dead cells and extracellular DNA could function as template in the LAMP assay.In the incubation at 63℃,viable bacteria in the LAMP reaction mixture lysed completely within 2 min,providing DNA template for nucleic acid amplification.The Stx1 gene in diluted culture medium,spiked tap water,spiked seawater and real seawater all could be detected,with or without the step of DNA extraction.We found that the complex substances in real sample(e.g.natural seawater)exhibited considerable inhibitory effect on the sensitivity of the LAMP assay.These outcomes are meaningful for building a point-of-care strategy by employing the LAMP assay for environmental monitoring,bio-resource surveys,food safety,etc.in particular those based on environmental DNA.展开更多
文摘The abnormal metabolic activity of the tumor can increase the oxygen consumption in tumor cells,and the poor blood perfusion often happens in tumor regions as well,which are the main reasons that result in a hypoxic situation in the tumor.A fluorescence probe,AQD,with selective response toward hypoxia was designed for the detection of hypoxic tumor cells,which was obtained by the covalent connection of a large planar conjugated fluorophore with good fluorescence stability and a N,N-dimethylaniline moiety via the azo bond.The introduction of the azo bond in AQD caused significant fluorescence emission quenching,and the probe was reduced under hypoxic conditions to release the fluorophore via breaking the azo bond,resulting in the gradual recovery of fluorescence emission.Probe AQD exhibited a remarkable fluorescence response in hypoxic conditions,high selectivity,and good biocompatibility,which was successfully used for the imaging of hypoxic tumor cells and realized the detection of hypoxic A549 cells.
基金Supported by the Natural Science Foundation of Heilongjiang Province of China(LH2023C016)the Key Research and Development Program of Heilongjiang Province of China(2022ZX01A24)the National Modern Agricultural Industry Technology System(CARS36)。
文摘Somatic cell count detection is the daily work of dairy farms to monitor the health of cows.The feasibility of applying near-infrared spectroscopy to somatic cell count detection was researched in this paper.Milk samples with different somatic cell counts were collected and preprocessing methods were studied.Variable selection algorithm based on hybrid strategy and modelling method based on ensemble learning were explored for somatic cell count detection.Detection model was used to diagnose subclinical mastitis and the results showed that near-infrared spectroscopy could be a tool to realize rapid detection of somatic cell count in milk.
文摘As a new form of fluorescent carbon nanomaterials, carbon dots （CDs） have many advantages such as simplicity of synthesis, low biological toxicity, resistance to photobleaching, excellent in biocompatibility and easy to modify. As the most inorganic mineral of human hard tissues including bone and tooth, calcium phosphate （CaP） materials have high biocompatibility and good biodegradability. The hydroxyapatite （HA）, a common type of calcium phosphate, has been widely used in drug delivery, removal of heavy metal ions, gene transfection and other biomedical fields. Herein, a novel method for preparation of fluorescent calcium phosphate/carbon dot （ CaP/ CD） hybrid composites was described. We first prepared CDs with a quantum yield of 51.5 % by carbonization of citric acid with polyethylenimine （PEI） in one step. Next, the fluorescent CaP/CD hybrid composites upon UV ex- citation were obtained in the presence of carboxymethyl cellulose （CMC） as a template and CD as a co-template. The as-prepared CaP/CD hybrid composites consisted of irregularly shaped nanorods with a length of 50 - 140 nm and a diameter of 10- 25 nm were characterized by transmitted electron microscopy （TEM）. And the highly mag- nified TEM image of CaP/CD hybrid composites showed that tens of CDs in shape of nanodot indeed existed in the CaP/CD hybrid composites. More importantly, CDs enabled the CaP/CD hybrid composites to emit bright blue flu- orescence under UV irradiation. In addition, the result of X-ray powder diffraction （XRD） patterns indicated that the crystalline phase of CaP/CD hybrid composites were in good agreement with those of hexagonal HA （JCPDS Da- ta Card 09-0432）. Moreover, it was found that the as-synthesized CaP/CD hybrid composites were potentially use- ful in detecting the concentration of Cu2＋ and imaging the cell with nontoxic as potential fluorescent probes.
文摘When the loop-mediated isothermal amplification(LAMP)assay is used for detecting target genes,DNA extraction is unnecessary in many cases.Simple pretreatment(e.g.heating)is enough to obtain rather sensitive responses.Even test samples without any pretreatment can be used as template.This feature suggests that LAMP is superior to PCR in developing point-of-care test strategies.In this study,using Stx1 gene from E.coli as model,we verified that viable cells,dead cells and extracellular DNA could function as template in the LAMP assay.In the incubation at 63℃,viable bacteria in the LAMP reaction mixture lysed completely within 2 min,providing DNA template for nucleic acid amplification.The Stx1 gene in diluted culture medium,spiked tap water,spiked seawater and real seawater all could be detected,with or without the step of DNA extraction.We found that the complex substances in real sample(e.g.natural seawater)exhibited considerable inhibitory effect on the sensitivity of the LAMP assay.These outcomes are meaningful for building a point-of-care strategy by employing the LAMP assay for environmental monitoring,bio-resource surveys,food safety,etc.in particular those based on environmental DNA.
