Described are substituted imidazo[1,2-a]pyrazine compounds, which are coelenterazine analogues, kits comprising the analogues, and methods of using the compounds for the detection of luminescence in luciferase-based assays. Also described are methods from making the compounds, such as a method using aminopyrazine acetophosphonates as synthesis intermediates.

Exemplary embodiments of the present disclosure include a combined catheter-based optical coherence tomography-two-photon luminescence (OCT-TPL) imaging system. Exemplary embodiments further include methods to detect, and further characterize the distribution of cellular components (e.g., macrophage, collagen/elastin fiber, lipid droplet) in thin-cap fibroatheromas with high spatial resolution in vivo.

The invention relates to ligands and complexes of metal ions with the ligands useful in various applications, including therapeutic and diagnostic applications.

The invention relates to chemical compounds and complexes that can be used in therapeutic and diagnostic applications.

Provided is a preparation method of near-infrared silver sulfide quantum dots. The silver sulfide quantum dots have hydrophilic groups derived from a mercapto-containing hydrophilic reagent attached on the surface thereof, and the hydrophilic reagent is any one of mercaptoacetic acid, mercaptopropionic acid, cysteine, cysteamine, thioctic acid and ammonium mercaptoacetate or any combination thereof. The silver sulfide quantum dots have high fluorescence yield, good fluorescence stability, good biocompatibility and uniform sizes. The preparation method has moderate reaction conditions, simple operation, short production cycle, good reproducibility and is easy to control. The silver sulfide quantum dots can be used in the application of cellular imaging and biological tissue imaging.

A method is provided for deep tissue imaging using multi-photon excitation of a fluorescent agent. The fluorescent agent is irradiated with an ultrafast laser to produce an excited singlet state (S.sub.n) which subsequently undergoes non-radiative relaxation to a first singlet state (S.sub.1). The S.sub.1 state undergoes fluorescence to the ground state S.sub.0 to produce an emission wavelength. Both the excitation and emission wavelengths are within the near infrared optical window, thereby permitting deep tissue penetration for both the incoming and outgoing signals.

Described are coelenterazine analogues, methods for making the analogues, kits comprising the analogues, and methods of using the compounds for the detection of luminescence in luciferase-based assays.

The present invention is in the field of bioluminescence in biology and/or medicine. In particular, the invention provides imidazopyrazine derivatives, processes for preparation thereof, and their uses as luciferins.

A nonlinear optical process on increasing the signal in SRS microscope by Resonant Stimulated Raman Scattering (RSRS) combines both RRS and SRS nonlinear processes, in absorber and host such a -carotene-methanol solution, Flavins, or other key absorbers in tissues. The observed effect of enhanced RSRS in small signal gain is attributed to RR process in absorber -carotene that transferring excess vibrations to host methanol from anharmonic vibrational interactions between the solute -carotene in resonance with the solvent methanol vibrations. SRS microscopy signals are improved in RSRS microscope for imaging vibrational states in lipids CH2 and proteins CH3 in cancer tissues from RR in Flavins or other native chromophores in tissue and for applications in other areas of neuroscience and biomedicine, potentially enhancing signals in the RSRS microscope by 2 to 1000 times.

The invention relates to compounds suitable for use in an imaging agent said imaging agent showing an improved pharmacokinetic profile.