Nano-dots in Mammalian Gametes Imagining1
The Nano-dots, or Quantum Dots (QD), are nano-scale semiconductor devices with diameter up to 10nm, which were first discovered in 1980s2. Once stimulated, they give emission of light with specific colours, which is then visualised1-3. These nano particles have high size-tunability, once illuminated, different emission wavelength can be obtained by manipulating the size of dots3. Inorganic QDs are made up of two components, an atom-cluster core with selenium or cadmium, and a shell made of inorganic materials. The inorganic shell has ability to cross-link with larger organic particles such as peptides and DNA, assuring their application in biotechnical field, such as biological tags and bio-imaging sources2. Because of their high extinction coefficient, quantum dots also have intensive application in optical-related industry, such as in solar cell and photodetector devices2.
Once attached on specific proteins, quantum dots become an effective tool in bioluminescence imaging3. The migration of target cell or protein can be tracked, providing valuable information in embryology, physiology and pharmacokinetics field3. A number of biomedical researches have applied this technology, such as cancer study and Parkinson’s diseases study. Large amount of information can be obtained through nanodots observation, giving numerous convenience in research. Last year, self-illuminating quantum dots were used by an US group in the study of mammalian gamete maturation. Currently, the detail of gametes maturation and early embryonic development process are still remains to be demonstrated in detail1. In their research, pre-treated porcine sperm, cumulus-oocyte complexes were labelled with quantum dots that linked with luciferase and peptides. The samples under different experimental conditions were then treated with the light-emitting molecule, coelenterazine, and processed to bioluminescence imaging. IVIS imaging system was used for instant sample imaging within 5 minutes after injection, though which nanoparticles in samples were visualised. Bio-distribution of nanoparticles in samples was also observed by the confocal fluorescence microscopy, hyperspectral fluorescence microscopy and transmission electron microscopy imaging for confirmation purpose1. Bioluminescence observation suggested a significant proportion of samples were successfully labelled with nanodots and they can be clearly visualised in all three different experimental conditions: in vitro (labelled spermatozoa and oocytes), ex vivo (intrauterine labelled spermatozoa), and in situ (labelled follicles during its maturation process)1. Migration locus for labelled nanodots were also observed during their incubation and growth period. Images suggested nanodots tend to accumulate in area with high levels of plasminogen, a fertilisation regulator1. In female reproductive track, the oviduct section showed higher nanodots intensity compared to the uterine horn1. However, the in situ did not give adequate information for the study and an optimised strategy is needed1. All bioluminescence observations above have high consistency with the data from fluorescence and hyperspectral imaging, which entails quantum dots labelling was able to be used as a novel bio-imaging method in studying dynamic changes …show more content…
The quantum nanodots can be clearly visualised under stable status, but the oocyte maturation process is too long to perform the real-time monitoring1. Therefore, this method has the limitation to visualise long-lasting cellular or tissue events. Another problem related with the method is the quality of the image, all tissues have some detectable background signals, which may interfere with the nanodots signal, leading to reduced detecting sensitivity6. Thus, choosing correct nanodots and signal detectors based on type of studied sample is also a big workload for
The Nano-dots, or Quantum Dots (QD), are nano-scale semiconductor devices with diameter up to 10nm, which were first discovered in 1980s2. Once stimulated, they give emission of light with specific colours, which is then visualised1-3. These nano particles have high size-tunability, once illuminated, different emission wavelength can be obtained by manipulating the size of dots3. Inorganic QDs are made up of two components, an atom-cluster core with selenium or cadmium, and a shell made of inorganic materials. The inorganic shell has ability to cross-link with larger organic particles such as peptides and DNA, assuring their application in biotechnical field, such as biological tags and bio-imaging sources2. Because of their high extinction coefficient, quantum dots also have intensive application in optical-related industry, such as in solar cell and photodetector devices2.
Once attached on specific proteins, quantum dots become an effective tool in bioluminescence imaging3. The migration of target cell or protein can be tracked, providing valuable information in embryology, physiology and pharmacokinetics field3. A number of biomedical researches have applied this technology, such as cancer study and Parkinson’s diseases study. Large amount of information can be obtained through nanodots observation, giving numerous convenience in research. Last year, self-illuminating quantum dots were used by an US group in the study of mammalian gamete maturation. Currently, the detail of gametes maturation and early embryonic development process are still remains to be demonstrated in detail1. In their research, pre-treated porcine sperm, cumulus-oocyte complexes were labelled with quantum dots that linked with luciferase and peptides. The samples under different experimental conditions were then treated with the light-emitting molecule, coelenterazine, and processed to bioluminescence imaging. IVIS imaging system was used for instant sample imaging within 5 minutes after injection, though which nanoparticles in samples were visualised. Bio-distribution of nanoparticles in samples was also observed by the confocal fluorescence microscopy, hyperspectral fluorescence microscopy and transmission electron microscopy imaging for confirmation purpose1. Bioluminescence observation suggested a significant proportion of samples were successfully labelled with nanodots and they can be clearly visualised in all three different experimental conditions: in vitro (labelled spermatozoa and oocytes), ex vivo (intrauterine labelled spermatozoa), and in situ (labelled follicles during its maturation process)1. Migration locus for labelled nanodots were also observed during their incubation and growth period. Images suggested nanodots tend to accumulate in area with high levels of plasminogen, a fertilisation regulator1. In female reproductive track, the oviduct section showed higher nanodots intensity compared to the uterine horn1. However, the in situ did not give adequate information for the study and an optimised strategy is needed1. All bioluminescence observations above have high consistency with the data from fluorescence and hyperspectral imaging, which entails quantum dots labelling was able to be used as a novel bio-imaging method in studying dynamic changes …show more content…
The quantum nanodots can be clearly visualised under stable status, but the oocyte maturation process is too long to perform the real-time monitoring1. Therefore, this method has the limitation to visualise long-lasting cellular or tissue events. Another problem related with the method is the quality of the image, all tissues have some detectable background signals, which may interfere with the nanodots signal, leading to reduced detecting sensitivity6. Thus, choosing correct nanodots and signal detectors based on type of studied sample is also a big workload for