As a new type of carbon nanomaterials, fluorescent carbon dots (fluorescent CDs) have many advantages when compared with the traditional fluorescent probes. They are photoluminescence stable and resistance to photo bleaching. Moreover, they are excellent in biocompatibility, low-toxic and easy to modify. All these above make them a promising optical image material as a probe in optical image. This article reviews structure, the common carbon sources, the preparation methods, and the light-emitting principles of the carbon dots. We also introduce the research progress of fluorescent carbon dots in biomedicine, and the problems need to be resolved in the study of fluorescent CDs.
Carbon ; chemistry ; Fluorescent Dyes ; chemistry ; Nanostructures ; chemistry ; Quantum Dots ; chemistry

Genetic code expansion (GCE) allows the incorporation of unnatural amino acids into proteins via using stop codons. GCE may achieve site-specific labeling of proteins in combination with the click reaction. Compared with other labeling tools such as fluorescent proteins and tagged antibodies, the compound molecules used in protein labeling by GCE technology are smaller, and therefore, may less interfere the conformational structure of proteins. In addition, through click reaction, GCE allows a 1:1 stoichiometric ratio of the target protein molecule and the fluorescent dye, and the protein can be quantified based on the fluorescence intensity. Thus, GCE technology has great advantages in the researches that require the exposition of living cells under high laser power for longer time, for example, in the context of single molecule tracing and super-resolution microscopic imaging. Meanwhile, this technology lays the foundation for improving the accuracy of positioning and molecule counting in the imaging process of living cells. This review summarized the GCE technology and its recent applications in functionally characterizing, labeling and imaging of proteins.
Amino Acids/chemistry* ; Fluorescent Dyes/chemistry* ; Genetic Code ; Proteins/chemistry*

OBJECTIVETo explore a method for combining Fluoro-Jade B (FJB) staining with immunofluorescent staining in rats with focal cortical infarction.

METHODPermanent distal middle cerebral artery occlusion (dMCAO) was induced in rats by electrocoagulation. The rat models were randomized into two groups, and frozen sections of the brain tissues from each group were stained with FJB followed by immunofluorescent staining or in the reverse order.

RESULTSFJB staining followed by immunofluorescence staining clearly visualized both FJB-positive and immunofluorescence-positive cells in the frozen sections, but the staining protocol in the reverse sequence failed to clearly show the immunofluorescence-positive cells.

CONCLUSIONFJB staining prior to immunofluorescence staining does not affect the staining effect of protein immunofluorescent staining and better visualizes the positive cells.

Animals ; Brain ; pathology ; Fluoresceins ; chemistry ; Fluorescent Antibody Technique ; methods ; Fluorescent Dyes ; chemistry ; Infarction, Middle Cerebral Artery ; Rats ; Staining and Labeling ; methods

We prepared protoplasts from Salvia miltiorrhiza Bunge suspension culture cells. Then, the protoplasts' vitality and functions were tested by fluorescein diacetate staining method and Fluo-3/AM flourescent probe. The optimal condition of protoplast isolation was Cellulase R-10 1.5%, Pectinase Y-23 0.3%, Macerozyme R-10 0.5%, 40 r/min 12 h, 600 r/min 5 min, and the protoplasts yield was 1.1x10(6) cells/g FW, the vitality was more than 95% by using fluorescein diacetate staining method. It has been confirmed that calcium fluorescent probe Fluo-3/AM can be successfully loaded into protoplasts.
Aniline Compounds ; chemistry ; Cell Culture Techniques ; Cellulase ; chemistry ; Fluorescent Dyes ; chemistry ; Protoplasts ; chemistry ; Salvia miltiorrhiza ; growth & development ; Xanthenes ; chemistry

Using fluorescein diacetate labeled HK-2 cells, a fast method for screening nephrotoxic components in traditional Chinese medicines (TCMs) was proposed in this study. The methodology validation showed that the linearity, stability and accuracy of the proposed method were suitable for screening nephrotoxic components in vitro . This method was further applied on screen 352 components from 32 Chinese Pharmacopoeia-indexed toxic TCMs. The results indicated that 31 components from 14 toxic TCMs, including Badou, had significant toxicity on HK-2 cells, which suggested these components may cause nephrotoxicity. The components from the other 18 toxic TCMs had no significant toxicity on HK-2 cells.
Biological Assay ; methods ; Cell Line ; Drugs, Chinese Herbal ; toxicity ; Fluorescent Dyes ; chemistry ; Humans ; Kidney ; drug effects

Fluorescent Linear Labelling technique is an effective, single-tube and linear amplification method. The sample cDNA was synthesized from total RNA, and was labelled antisense cRNA from double-stranded cDNA with T7RNA polymerase; it can be used for hybridization to oligonucleotide biochip. Fluorescent Linear Labelling Method can result in 50- to 100-fold higher degrees of amplification, and has been shown to retain information on transcript abundance, thus making it an efficient, robust technique for fluorescent labelling on biochip.
Fluorescent Dyes ; chemistry ; Humans ; Oligonucleotide Array Sequence Analysis ; methods ; Staining and Labeling ; methods

OBJECTIVETo observe the influence of electroacupuncture (EA) on indocyanine green (ICG) metabolism in the liver and the action mechanism of acupuncture for hepatic regulation.

METHODSForty Kunming mice were randomly divided into an EA group and a control group, 20 cases in each one. Combined with classical hepatic metabolism test of ICG, after tail vein injection of ICG, twenty mice were treated with EA at "Zusanli" (ST 36) for 20 min. The ICG fluorescence intensity and distribution in the liver were observed with animal in vivo fluorescence imaging apparatus during 20 min of EA and 60 min of needle withdrawal. Twenty mice, taken as control group, were treated with ICG injection and no EA. The differences of fluorescence intensity and distribution in both groups were compared.

RESULTS(1) There was blocking and gathered fluorescent sign in both groups when ICG was injected immediately. With the extension of observation time, the fluorescence brightness and area were increased until 30 min of injection. This was in accordance with known metabolism activities of ICG in the liver. (2) At 10 min and 20 min of EA and after needle withdrawal, compared with the control group, the fluorescence intensity in the liver of the EA group was weaker and the distribution area was smaller. (3) According to quantitative statistics of fluorescence intensity, at each time point of treatment, the value in the control group was higher than that in the EA group, which appeared regularly all along. As for the total mean difference of ICG fluorescence intensity at all time points, there was statistical difference between the two groups (P < 0.05).

CONCLUSIONEA could reduce fluorescence intensity and lasting time of ICG, indicating that EA accelerates metabolic process of ICG in the liver. Also it is feasible to apply animal in vivo fluorescence imaging technology to the principle research of acupuncture effect.

Animals ; Electroacupuncture ; Female ; Fluorescent Dyes ; chemistry ; metabolism ; Indocyanine Green ; chemistry ; metabolism ; Liver ; chemistry ; metabolism ; Male ; Mice ; Whole Body Imaging

This study evaluated the meiotic competence of buffalo oocytes with different layers of cumulus cells. A total of 588 oocytes were collected from 775 ovaries averaging 0.78 oocytes per ovary. Oocytes with homogenous cytoplasm (n = 441) were selected for in vitro maturation (IVM) and divided into four groups based on their cumulus morphology: a) oocytes with > or == 3 layers of cumulus cells, b) 1-2 layers of cumulus cells and oocytes with partial remnants or no cumulus cells to be cocultured c) with or d) without cumulus cells. Oocytes in all four groups were matured in 100 microL drop of TCM-199 supplemented with 10microgram/mL follicle stimulating hormone (FSH), 10microgram/mL luteinizing hormone (LH), 1.5microgram/mL estradiol, 75microgram/mL streptomycin, 100 IU/mL penicillin, 10 mM Hepes and 10% FBS at 39degrees C and 5% CO2 for 24 hours. After IVM, cumulus cells were removed from oocytes using 3 mg/mL hyaluronidase, fixed in 3% glutaraldehyde, stained with DAPI and evaluated for meiotic competence. The oocytes with > or ==3 layers of cumulus cells showed higher maturation rates (p <0.05: 64.5%) than oocytes with partial or no cumulus cells (8.6%) and oocytes co-cultured with cumulus cells (34.5%) but did not differ from oocytes having 1-2 layers of cumulus cells (51.4%). The degeneration rates were higher (p < 0.05) for oocytes with partial or no cumulus cells (51%) than rest of the groups (range: 13.8% to 17.4%). These results suggest that buffalo oocytes with intact layers of cumulus cells show better IVM rates than oocytes without cumulus cells and the co-culture of poor quality oocytes with cumulus cells improves their meiotic competence.
Animals ; Buffaloes/*physiology ; Female ; Fluorescent Dyes/chemistry ; Indoles/chemistry ; Meiosis/*physiology ; Microscopy, Fluorescence/veterinary ; Oocytes/cytology/growth&development/*physiology

Relatively uniform-sized nanoparticles made of poly (lactic-co-glycolic acid) (PLGA) were prepared by premix membrane emulsification method. After the drug loading property was completed, the dynamic tissue distribution of nanoparticles was recorded. With the average particle size and span as indexes, membrane pore size, number of passing membrane times, membrane pressure, volume ratio of oil-water phase and the concentration of poly(vinyl alcohol) (PVA) in external water phase were investigated by single factor test, the optimum preparation technology of blank PLGA nanlparticles was as following: pore size of SPG membrane was 1 μm, membrane pressure was 1. 15 MPa, the number of passing membrane time was 3, the mass fraction of PVA of 2%, volume ratio of oil-water phase of 1 : 5. Prepared nanoparticles were round with smooth surface, the mean diameter was 332.6 nm, span was 0.010, the confocal laser scanning microscope (CLSM) concluded that fluorescent substance is uniform composizion in PLGA nanoparticle, and the in vivo imaging technology in mice include that the nanoparticles show good liver and spleen targeting property.
Animals ; Drug Carriers ; chemistry ; Drug Delivery Systems ; instrumentation ; Emulsions ; chemistry ; Fluorescent Dyes ; chemistry ; Lactic Acid ; chemistry ; Mice ; Mice, Nude ; Nanoparticles ; chemistry ; Particle Size ; Polyglycolic Acid ; chemistry

The lipase labeled with the fluorescein isothiocyanat (FITC) was immobilized on the derivatives of the polyethylene glycol. The article discussed the effect of factors on the characters of lipase and analyzed the relationships among the activity of lipase, conformation, and fluorescence spectrum while the activity and the fluorescence spectrum of immobilized lipase were determined. The results demonstrated that polyethylene glycol 400-diacrylate could form appropriate network to improve the activity of enzyme. Adding ligand induced the lipase's catalytic conformation to increase the activity twice more than before. The active centre of lipase could be released by the extraction of ligand thus increasing the activity. After immobilization, the stability of labeled lipase improved greatly: immobilized lipases retained more than 70% and 60% of initial activity under conditions of 90 degrees C and strong acid or alkali, respectively. After immersing immobilized lipases into guanidine hydrochloride or urea for 15 days, the lipases retained upwards of 70% activity. The fluorescence spectrum could obviously reflect the changes of the activity and conformation of lipase. The fluorescence intensity was the minimum in the optimal pH and temperature. In the denaturing agent it declined as time passed. These results indicated that the unfolded processes of immobilized lipases are different under different conditions.
Dextrans ; chemistry ; Enzyme Stability ; Enzymes, Immobilized ; chemistry ; metabolism ; Fluorescein-5-isothiocyanate ; analogs & derivatives ; chemistry ; Fluorescent Dyes ; chemistry ; Lipase ; chemistry ; metabolism ; Polyethylene Glycols ; chemistry ; Protein Unfolding ; drug effects