This article describes the application of the fastest commercially available video-rate atomic force microscope (AFM) for studying the molecular dynamics of biological samples with a temporal resolution reaching 20 ms per frame. High-speed AFM was used for monitoring the kinetics of the temperature-induced ripple phase transition in supported lipid bilayers, DNA origami streptavidin-biotin binding, thermodynamic rehybridization of DNA, collagen type I fibrillogenesis, and the mobile annexin V trimer dynamics in 2D protein crystals. With no further need for sample processing, the applied method offers a breakthrough in molecular and sample dynamics measurements by enabling the real-time visualization of molecular processes and structural transitions at near-native conditions.

The aim of our study was to compare the viability of sperm cells from transgenic (mWAP-hFVIII gene) or non-transgenic (normal) rabbit males as assessed by viability (SYBR-14/PI) and apoptosis (annexin V) tests. These results were evaluated using female conception rates following insemination with the respective sperm samples. No significant differences were found in concentration and motility between transgenic and non-transgenic spermatozoa. Spermatozoa from both transgenic (63.05 ± 20.05%) or non-transgenic (65.75 ± 22.15%) males, stained with SYBR-14 (green), were found to be morphologically normal. In both groups, the highest proportion of annexin V-positive sperm staining was found in the post-acrosomal part of the sperm head (8.66 and 27.53%). The percentage of sperm that stained with SYBR-14/PI or with annexin V/DAPI was correlated with liveborn in transgenic rabbits (R2 = 0.6118 and R2 = 0.2187, respectively) or non-transgenic rabbits (R2 = 0.671 and R2 = 0.3579, respectively). These data indicate that there was no difference in the viability of rabbit transgenic and non-transgenic spermatozoa when determined by both fluorescence assays.