We have demonstrated widely tunable Yb:fiber-based laser sources, aiming to replace Ti:sapphire lasers for the nJ-level ultrafast applications, especially for the uses of nonlinear light microscopy. We investigated the influence of different input parameters to obtain an expansive spectral broadening, enabled by self-phase modulation and further reshaped by self-steepening, in the normal dispersion regime before the fiber damage. We also discussed the compressibility and intensity fluctuations of the demonstrated pulses, to reach the transform-limited duration with a very low intensity noise. Most importantly, we have demonstrated clear two-photon fluorescence images from UV-absorbing fluorophores to deep red dye stains.
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http://dx.doi.org/10.1364/BOE.422668 | DOI Listing |
Anal Chem
January 2025
Zhejiang Engineering Research Center of Advanced Mass Spectrometry and Clinical Application, Institute of Mass Spectrometry, School of Materials Science and Chemical Engineering, Ningbo University, Ningbo, Zhejiang 315211, China.
Bioimaging technology has been broadly used in biomedicine, and the growth of multimodal imaging technology based on synergistic advantages can overcome the shortcomings of traditional single-modal bioimaging methods and attain high specificity and sensitivity in the fields of bioimaging and biosensing. The analysis of low-abundance microRNAs (miRNAs) in complex organisms is of high importance for early-stage diagnosis and clinical treatment of tumors. In our current study, a biosensing nanoplatform based on Tf-AuNCs and MnO nanosheets was developed for multimodal imaging of tumor cells.
View Article and Find Full Text PDFBackground: Preclinical Alzheimer's disease research has gained traction as a potential point of intervention, though it is relatively unknown how early stages of the disease impact cortical health. The following study utilizes optical imaging methods (Figure 1) to characterize changes in neuronal, glutamate, and hemodynamic activities in a preclinical amyloidosis mouse model of the disease.
Method: Five (n = 5; 2 females & 3 males) APPswe/PS1dE9 x Thy1-jRGECO1a double transgenic mice were breed for whole-brain fluorescent imaging of neuronal activity.
Microcirculation
January 2025
Geoffrey Jefferson Brain Research Centre, Manchester Academic Health Science Centre, Northern Care Alliance NHS Foundation Trust, University of Manchester, Manchester, UK.
Objective: Cerebral blood flow (CBF) decline is increasingly recognized as an area of importance for targeting neurodegenerative disorders, yet full understanding of the mechanisms that underlie CBF changes are lacking. Animal models are crucial for expanding our knowledge as methods for studying global CBF and neurovascular coupling in humans are limited and require expensive specialized scanners.
Methods: Use of appropriate animal models can increase our understanding of cerebrovascular function, so we have combined chronic cranial windows with in vivo two-photon and laser speckle microscopy and ex vivo capillary-parenchymal arteriole (CaPA) preparations.
Chem Commun (Camb)
January 2025
State Key Laboratory of Applied Organic Chemistry and College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, Gansu 730000, China.
A fluorescence quenching mechanism using linear diselenides was proposed for the first time through a combination of intramolecular charge transfer (ICT) and Förster resonance energy transfer (FRET). Herein, we synthesized and screened a two-photon fluorescent probe AFC-SeSe, demonstrating a remarkable 300-fold increase in response to glutathione (GSH). Additionally, AFC-SeSe enabled real-time observation of increased thiol levels following treatment within a short timeframe in a mouse model of stroke.
View Article and Find Full Text PDFSci Adv
January 2025
Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA.
Microbial rhodopsin-derived genetically encoded voltage indicators (GEVIs) are powerful tools for mapping bioelectrical dynamics in cell culture and in live animals. Förster resonance energy transfer (FRET)-opsin GEVIs use voltage-dependent quenching of an attached fluorophore, achieving high brightness, speed, and voltage sensitivity. However, the voltage sensitivity of most FRET-opsin GEVIs has been reported to decrease or vanish under two-photon (2P) excitation.
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