[Fluorescence Anisotropy and Applications Based on Functional Nucleic Acid Recognition].

Based on the difference of the depolarization of the emitted light before and after the interaction of molecules, fluorescence anisotropy, also known as fluorescence polarization, can be beneficial for the study of interactions and the detection of the targets. In 1950s, Gregorio Weber first studied the interactions between dansyl chloride and bovine serum albumin or ovalbumin with fluorescence anisotropy method, which paved the way for fluorescence anisotropy in biochemical applications. Since the early 1990s, functional nucleic acids (FNAs, including aptamers, and nucleic acid enzymes) were discovered and synthesized, which have been widely used in functional nucleic acid-based sensing. Aptamers are oligonucleotides that can recognize and bind specifically to various molecular targets. The fluorescence anisotropy methods which are based on aptamer recognition have the advantages of high selectivity, sensitivity and through-put. They play an important role in the study of interaction with protein, nucleic acids and small molecules. However, the way of enhancing the fluorescence anisotropy change of small molecules associated with the binding events is challenging. This paper reviews the basic principles and designs of fluorescence anisotropy methods bases on functional nucleic acid recognition for study and detection of proteins, nucleic acids and small molecules that play an important role in the life activity.

[Successful pregnancy following laser-assisted selection of viable but immotile spermatozoa for intracytoplasmic sperm injection: A report of 2 cases].

OBJECTIVE: To investigate the feasibility and clinical application value of selecting viable spermatozoa by noncontact diode laser. METHODS: We obtained immotile spermatozoa from 2 infertile men with obstructive azoospermia or severe asthenospermia and selected viable spermatozoa using a single laser shot at the sperm tail. Those that responded to the laser shot by a curling reaction of the tail were regarded as presumably viable and used for intracytoplasmic sperm injection (ICSI). RESULTS: The mean fertilization rate was 88.89% after ICSI with the laser-selected viable spermatozoa. Both of the embryo transfers resulted in a single pregnancy. CONCLUSION: Noncontact diode laser is a useful alternative for the assessment of sperm viability, which may help to achieve successful pregnancy.

[Effects of IVF versus ICSI on the outcomes of elective blastocyst culture].

OBJECTIVE: To explore the effects of different fertilization methods on the outcomes of elective blastocyst culture. METHODS: We retrospectively analyzed the outcomes of elective blastocyst culture for 1 153 cycles of IVF and 205 cycles of ICSI performed between january 2009 and December 2012. RESULTS: A total number of 14 748 embryos in the IVF group and 2 655 embryos in the ICSI group underwent sequential blastocyst culture, with 7 871 blastocysts formed in the former and 1 210 in the latter. No cycles were canceled for no blastocyst formation in either of the two groups. The rates of quality embryos, blastocyst formation and embryo utilization were significantly higher in the IVF than in the ICSI group (64.77 vs 58.72%, 53.37 vs 45.57%, and 60.06 vs 52.17%, all P < 0.05), but the rates of implantation, clinical pregnancy and abortion showed no significant differences between the two groups (48.94 vs 51.43%, 49.03 vs 52.02%, and 11.69% vs 15.56, all P > 0.05). CONCLUSION: With the same inclusion criteria of selective blastocyst culture, IVF has a lower risk of cycle cancellation due to no blastocyst formation and therefore may effect higher rates of blastocyst formation and embryo utilization than ICSI. Our study suggested that appropriate inclusion criteria of selective blastocyst culture should be laid down according to different fertilization methods.