Resolution Enhancement and Background Suppression in Optical Super‐Resolution Imaging for Biological Applications

Abstract

For decades, the spatial resolution of conventional far‐field optical imaging has been constrained due to the diffraction limit. The emergence of optical super‐resolution imaging has facilitated biological research in the nanoscale regime. However, the existing super‐resolution modalities are not feasible in many biological applications due to weaknesses, like complex implementation and high cost. Recently, various newly proposed techniques are advantageous in the enhancement of the system resolution, background suppression, and improvement of the hardware complexity so that the above‐mentioned issues could be addressed. Most of these techniques entail the modification of factors, like hardware, light path, fluorescent probe, and algorithm, based on conventional imaging systems. Particularly, subtraction technique is an easily implemented, cost‐effective, and flexible imaging tool which has been applied in widespread utilizations. In this review, the principles, characteristics, advances, and biological applications of these techniques are highlighted in optical super‐resolution modalities.

Probing Biosensing Interfaces With Single Molecule Localization Microscopy (SMLM)

“…Roughly speaking, this process involves three separate steps: the first is drift correction, the second single emitter localization and third image reconstruction. The past decade has seen rapid advances in our understanding of emission patterns of single emitters, namely point spread function (PSF), and now higher order PSF fittings are available to enable 3D super-resolution imaging (Hao et al, 2013 ; von Diezmann et al, 2017 ; Li et al, 2020 ). Higher order drift correction methods, such as 3D drift control, has been shown to work efficiently…”

Accurate Background Reduction in Adaptive Optical Three-Dimensional Stimulated Emission Depletion Nanoscopy by Dynamic Phase Switching

“…13 There have been several hardware-based or software-based techniques addressing this background issue by directly subtracting the estimated background from the regular STED images. 14 In a method called stimulated emission double depletion (STEDD), an extra Gaussian pulse is added to an ordinary 3D-STED setup to measure the background. 15,16 Nonetheless, STEDD is optically complex due to its requirement of an extra beam path and careful synchronization design.…”

Dual-modulation difference stimulated emission depletion microscopy to suppress the background signal

“…The past decade has witnessed the development and the high significance of background removal approaches in STED microscopy 8,9 (see Table S1 in the Supplementary Material). Those methods can be divided into three categories: timedomain, space-domain, and phasor-domain methods.…”