Effect of spatial spectrum overlap on Fourier ptychographic microscopy

Fourier ptychographic microscopy(FPM)is a newly developed imaging technique which stands out by virtue of its high-resolution and wide FOV.It improves a microscope's imaging perfor-mance beyond the diffraction limit of the employed optical components by illuminating the sample with oblique waves of different incident angles,similar to the concept of synthetic aperture.We propose to use an objective lens with high-NA to generate oblique illuminating waves in FPM.We demonstrate utilizing an objective lens with higher NA to iluminate the sample leads to better resolution by simulations,in which a resolution of 0.28 pum is achieved by using a high-NA illuminating objective lens(NA=1.49)and a low-NA collecting objective lens(NA=0.2)in coherent imaging(λ=488 nm).We then deeply study FPM's exact relevance of convergence speed to spatial spectrum overlap in frequency domain.The simulation results show that an overlap of about 60%is the optimal choice to acquire a high-quality recovery(520*520 pixels)with about 2 min's computing time.In addition,we testify the robustness of the algorithm of FPM to additive noises and its suitability for phase objects,which further proves FPM's potential application in biomedical imaging.

Dark-vacuole Bodies Studying by High-resolution Label-free Microscopy Assisted with Fluorescence Technology

The intracellular logistics system,consisting of vesicles,plays a crucial role in cellular transport.However,there is a lack of research on the types and functions of intracellular vesicles,and new technologies are needed for further investigation.Recently,researchers have discovered a new subcellular structure known as Dark-vacuole bodies.The composition,function,and potential synergy with other organelles of these Dark-vacuole bodies remain unclear.In this study,we utilized the high-resolution label-free Fourier ptychographic microscopy,developed by our research group,along with fluorescence confocal technology,to study and analyze Dark-vacuole bodies.Our findings provide evidence of the influence of Dark-vacuole bodies on the morphology,distribution,movement,and cell cycle of living cells.Specifically,we analyzed the effects of drug induced stimulation of lipid drops and endosomes,promotion of cell endocytosis,and induction of cellular senescence on Dark-vacuole bodies.Our results indicate that Dark-vacuole bodies show little correlation with lipid drops and endocytosis vesicles,but are significantly associated with late endosomes.Furthermore,cellular senescence leads to a significant increase in the number and size of Dark-vacuole bodies.This study serves as a foundation for further confirming the nature of Dark-vacuole bodies as new organelles.