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@#Nerve-specific fluorescent agents can be used as nerve markers in animals to guide surgical procedures and reduce the incidence of intraoperative nerve injury.In this study, the structure of oxazine mother nucleus was modified.A series of oxazine derivative fluorescent dyes YQN-3-YQN-6 were obtained by mass spectrometry and 1H NMR, which can highlight the peripheral nerve structure of rats.Among a series of targeted fluorescent dyes, YQN-3 had emission peaks near NIR and showed highly specific nerve targeting signals in the brachial plexus and sciatic nerves 4 h after intravenous administration.In addition, YQN-3 can accurately locate and identify recurrent laryngeal nerves during thyroidectomy, thus preserving the integrity of these nerves during surgery.With its simple synthesis and low toxicity, YQW-3 can be potentially applied for clinical neural tissue imaging.
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The in vivo fate is a crucial factor that governs the successful translation of nanoformulations. However, one of the current biggest challenges is with the real-time monitoring of the body of the nanoparticles themselves. Conventional radioactive or fluorescent probes give signals even after they are disassociated from the particle matrix, generating interference to bioimaging and leading to misjudgment of results. Environment-responsive fluorescent dyes are regarded as promising tools due to signal switching in response to the changes in the environment. Currently, there are three categories of dyes in bioimaging of nanoparticles based on Förster resonance energy transfer (FRET), aggregation-induced emission (AIE) and aggregation-caused quenching (ACQ). They have similar characteristics that strong fluorescence is emitted when they are embedded in the matrix of nanocarriers, whereas the fluorescence quenches upon release from the matrix due to dissociation of nanocarriers. The fluorescence switching reflects the existing status of the nanocarriers and therefore helps to interpret the in vivo behaviors. FRET and AIE probes have been widely used in elucidating the interactions between nanoparticles and cell models. However, they show intrinsic defects in studying in vivo fate of nanoparticles. ACQ-based dyes are sensitive to water, a universal factor in the biological environment. Therefore, with the help of bioimaging equipment, the in vivo trafficking process of nanoparticles can be unraveled. This review article tends to provide an overview on the rationale, pros and cons and applications of the three categories of environment-responsive fluorescent dyes in the investigation of the in vivo fate of nanocarriers.
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Objective: To establish a method for the rapid detection of sterile preparations. Methods: Microbes in the sterile preparations were labeled by fluorescent dye SYTO9,and detected by flow cytometry. Meanwhile,the results from the routine examina-tion method recorded in Chinese Pharmacopoeia and those from the flow cytometry were compared. Results:The detection limit of in-jection and injection of sterile powder using flow cytometry was less than 10 cfu. It could be directly detected when the microbial con-tamination of the test samples was greater than 105cfu. When the amount of pollution was <10 cfu-104cfu, the detection time was shortened by 40%-70% when compared with that of the routine method. Conclusion:Flow cytometry used for the detection of microbi-ological contamination can shorten the time for positive result,which can be an effective supplement to the routine method.
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Optical molecular imaging is more and more widely used in the field of biomedical sciences due to its advantageous properties such as non-invasive, real-time and high resolution. As a kind of important optical molecular imaging probe,the near-infrared fluorescent(NIRF)dyes exhibit less tissue absorption and strong tissue penetration,and has been gradually applied to the early diagnosis of tumors. Researchers have developed a number of NIRF dyes with high potential for clinical application by conjugating tumor-targeting ligands,nano-modifications and multimodal NIRF imaging, and have significantly improved the specificity and sensitivity of these NIRF dyes in tumor diagnosis. In this paper we provide a review on the application of NIRF dyes in tumor diagnosis.
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Objective To investigate the DNA staining efficiencies of 4 kinds of nucleic acid fluorescent dyes,including EB,SYBR Green Ⅰ,Gold View and AO,in single-cell gel electrophoresis (SCGE) assay,and the possibility to use a new nucleic acid fluorescent dye instead of EB.Methods The peripheral blood lymphocytes from healthy individuals were isolated and treated with 0,20,40,60 and 80 μg/mL of H2O2,respectively.Then,the DNA damages of lymphocytes were detected by the neutral SCGE assay.The DNA was stained with EB,SYBR Green Ⅰ,Gold View and AO dyes,respectively,and the staining results were observed and compared under a fluorescence microscope.In addition,the percentages of tail DNA (％ Tail DNA) from different staining methods were analyzed and compared.Results The results of SCGE showed that SYBR Green Ⅰ,Gold View and AO staining could well reflect the DNA damages of lymphocytes,and that the optimal concentrations for SYBR Green Ⅰ,Gold View and AO were 1 ×-5 ×,2 ×-5 × and 2-5 μg/mL,respectively.The regression coefficients for EB,SYBR Green Ⅰ,Gold View and AO were 2.71,2.81,2.73 and 2.75,respectively,which indicated that there was consistent dyeing effect between them.The results of ％ Tail DNA were stable with in 48 hours,and there was no significant difference between the 4 fluoresent dyes (P ＞ O.05).The inter-assay coefficients of variation (CVs) of SYBR Green Ⅰ,Gold View and AO were 6.92％,7.10％ and 8.25％,respectively,which were superior to that of EB (8.35％).The intra-assay CVs of SYBR Green Ⅰ and Gold View were 3.07％ and 2.74％,respectively,which were superior to that of EB (3.59％).Conclusion SYBR Green Ⅰ,Gold View and AO may be used for the nucleic acid fluorescent staining,and especially Gold View is more suitable for instead of EB in SCGE.
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This study aims to synthesize new phospholipids, 1,3-dipalmaminophospholipid(Pad-PC-Pad), and prepare shear-stress sensitive liposomes(SSSL). 1H NMR and MS indicated that Pad-PC-Pad were fully synthesized successfully. SSSL were prepared by filming-rehydration method with Pad-PC-Pad, which loaded calcein with aggregation-caused quenching(ACQ)characteristics to evaluate shear-stress sensitivity of liposomes and release behavior of liposomes in vitro. The results showed that the particle size of liposomes was 106.91 ± 1.24 nm and liposomes had lenticular morphology under transmission electron microscope. The release of calcein was increased with ultrasonic power, which suggests that the liposomes is shear-stress sensitive. Moreover, the liposomes exhibited a releasing effect for obstructed region under high shear-stress in a model system. Therefore, we synthesized quick functional phospholipid Pad-PC-Pad and the liposomes made from Pad-PC-Pad was shear-stress sensitive, which may be used for treatment of thrombosis.
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An analytical method of fluorescent dye-labeled oligonucleotides was established by ion pair reversed phase high performance liquid chromatography(IP-RP-HPLC) which was improved by optimizing the effects of triethylamine-acetic acid(TEAA)(0-0.15 mol/L), pH(4.5-7.0) and gradient. Comparing the retention of 5, 10 and 15-mer unlabeled oligonucleotides with that of 5'-carboxyfluorescein(5'FAM) labeled oligonucleotides, the mechanism of fluorescent dye-labeled oligonucleotides retention was studied. In addition, TaqMan~(TM) probes as wellas other common fluorescent dye-labeled oligonucleotides were concerned. The results showed that the best resolution of different length fluorescent dye-labeled oligonucleotides was observed under the condition of 0.01 mol/L TEAA and pH 7.0. The retention behavior of fluorescent dye-labeled oligonucleotides was different from that of unlabeled oligonucleotides significantly, and therefore they can be separated completely. The results indicated that the retention of unlabeled oligonucleotides enhanced with the increase of the length of molecule. In contrast, the retention of fluorescent dye-labeled oligonucleotides was reduced with the increase of the length of molecule. For the hydrophobicity of fluorescent dyes made a great impact on the retention, a longer retention time the labeled oligonucleotides would take while the hydrophobicity of fluorescent dyes was higher. However, the effect of the hydrophobicity was limited as the length was increased to a certain level.