Three-photon tissue imaging using moxifloxacin

Abstract

Moxifloxacin is an antibiotic used in clinics and has recently been used as a clinically compatible cell-labeling agent for two-photon (2P) imaging. Although 2P imaging with moxifloxacin labeling visualized cells inside tissues using enhanced fluorescence, the imaging depth was quite limited because of the relatively short excitation wavelength (<800 nm) used. In this study, the feasibility of three-photon (3P) excitation of moxifloxacin using a longer excitation wavelength and moxifloxacin-based 3P imaging were tested to increase the imaging depth. Moxifloxacin fluorescence via 3P excitation was detected at a >1000 nm excitation wavelength. After obtaining the excitation and emission spectra of moxifloxacin, moxifloxacin-based 3P imaging was applied to ex vivo mouse bladder and ex vivo mouse small intestine tissues and compared with moxifloxacin-based 2P imaging by switching the excitation wavelength of a Ti:sapphire oscillator between near 1030 and 780 nm. Both moxifloxacin-based 2P and 3P imaging visualized cellular structures in the tissues via moxifloxacin labeling, but the image contrast was better with 3P imaging than with 2P imaging at the same imaging depths. The imaging speed and imaging depth of moxifloxacin-based 3P imaging using a Ti:sapphire oscillator were limited by insufficient excitation power. Therefore, we constructed a new system for moxifloxacin-based 3P imaging using a high-energy Yb fiber laser at 1030 nm and used it for in vivo deep tissue imaging of a mouse small intestine. Moxifloxacin-based 3P imaging could be useful for clinical applications with enhanced imaging depth.

Trends in polymeric shape memory hydrogels and hydrogel actuators

“…Most research on these photo-thermal materials focuses on carbon-based materials, such as graphene oxide (GO) 111 and metallic nanoparticles such as iron oxide 112 or gold. 113 For example, Lee et al 114 fabricated a fast responding photo-actuator by combining a comb-type PNIPAM hydrogel matrix with magnetite nanoparticles ( Fig. 9-III).…”

Tunable Sponge‐Like Hierarchically Porous Hydrogels with Simultaneously Enhanced Diffusivity and Mechanical Properties

“…To date, most works that improve swelling ratio and swelling rate do so by increasing the porosity (ϕ), the total volume fraction of pores. [ 14,15 ] Superporous hydrogels, which boast the highest porosities and swelling rates among hydrogels, have been fabricated using porosigen, [ 16–18 ] phase separation, [ 19,20 ] particle crosslinking, [ 21 ] and gas‐blowing [ 22,23 ] techniques. The larger pore sizes effectively reduce the tortuosity of the hydrogel and facilitate faster and greater water transport through the polymer matrix.…”

Hydrodynamic pressure sensors with tunable sensitivity based on thermoresponsive hydrogels

“…Functional hydrogels can regulate their volume or elasticity responding to a wide variety of stimuli, such as temperature, 15,16,17 light, 18,19 pH, 20 for actuators, 21,22 microfluidic unites, 23 and tissue engineering applications 24 . PH‐responsive hydrogels with a fast response time has been integrated into microfluidic systems for sensing and actuation 25 Thermoresponsive hydrogels with lower critical solution temperature (LCST) can achieve volume‐phase transition around the LCST due to the coil‐globule transition of individual hydrogel chains 26 .…”