Journal of Innovative Optical Health Sciences

Fluorescence resonance energy transfer (FRET) is an important photophysical mechanism which finds many applications in biophotonics, particularly in biological sensing and imaging. It is well known, there are two major factors that determine the efficiency of FRET. One is the distance between the donor and the acceptor, and the other is the overlap of the donor's emission and the acceptor's absorption spectra. However, while the distance-modulation of FRET is very popular, the spectral-overlap-modulation draws much less attention.

In this talk, I would like to illustrate the importance of the strategy of spectral-overlap-modulation. The presentation will include our works on the construction of highly efficient FRET systems featuring the short and rigid linker between the donor and acceptor moieties, and several typical examples of spectral-overlap-modulation strategy applied in the development of ratiometric sensors.

Multifocal multiphoton microscopy (MMM) has recently become an important tool in biomedicine for performing three-dimensional fast fluorescence imaging. Using various beamsplitting techniques, MMM splits the near-infrared laser beam into multiple beamlets and produces a multifocal array on the sample for parallel multiphoton excitation and then records fluorescence signal from all foci simultaneously with an area array detector, which significantly improves the imaging speed of multiphoton microscopy and allows for high efficiency in use of the excitation light. In this paper, we discuss the features of several MMM setups using different beamsplitting devices, including a Nipkow spinning disk, a microlens array, a set of beamsplitting mirrors, or a diffractive optical element (DOE). In particular, we present our recent work on the development of an MMM using a spatial light modulator (SLM).

The adequate method of antibiotic choice is reported using the laser fluorescence analysis of blood plasma with the laboratory diagnostic device "Spectrolux-MB". The method is based on the ability of micro-organisms and products of their vital functions (metabolism) to fluoresce under laser radiation. The method of fluorescence analysis has great prospects in urgent surgery and other medicine brunches due to its high information content, low cost (compared to other methods of express-diagnostics) and high speed of information acquisition.

Purpose: To investigate the effects of rigid-gas-permeable contact lens (RGP-CL) wear on Zernike astigmatism and visual performance in myopic eyes. Methods: A wavefront sensor was used to evaluate Zernike astigmatism for 21 eyes with minimum astigmatism and 18 eyes with moderate astigmatism under three different modes of refractive correction: the RGP-CL, spectacle lens correcting spherical equivalent (SL) and spectacle lens fully correcting spherical error and astigmatism (fSL). Contrast visual acuity was assessed with a VA tester at four contrast levels and two luminance backgrounds. Results: Compared to the SL wear, RGP-CL wear changed the main axis astigmatism from -0.09 ± 0.34 to 0.34 ± 0.22 for the minimum astigmatism group, while the contrast VA was improved about 0.05 LogMAR (F = 8.06, p < 0.01). For the group with moderate astigmatism, significant reduction in was found for both fSL wear (t = 4.78, p < 0.001) and RGP-CL wear (t = 6.29, p < 0.0001). The changes in astigmatism were significantly correlated between the fSL and RGP-CL wears (r = 0.897, p < 0.0001 for ; and r = 0.643, p = 0.004 for . Contrast VA was significantly improved for both fSL and RGP-CL wears and the improvements were significantly correlated between each other for all four contrast levels and two backgrounds. Conclusion: RGP-CL wear induces astigmatism for the eyes with minor astigmatism probably due to a correction of corneal astigmatism and thus a manifesting of the lens astigmatism. For the astigmatic eyes, RGP-CL wear has similar effect on correcting astigmatism as the spectacle lens wear with spherical-cylinder correction and also produces similar visual improvement.

Fluorescence resonance energy transfer (FRET) technology had been widely used to study protein–protein interactions in living cells. In this study, we developed a ROI-PbFRET method to real-time quantitate the FRET efficiency of FRET construct in living cells by combining the region of interest (ROI) function of confocal microscope and partial acceptor photobleaching. We validated the ROI-PbFRET method using GFPs-based FRET constructs including 18AA and SCAT3, and used it to quantitatively monitor the dynamics of caspase-3 activation in single live cells stably expressing SCAT3 during staurosporine (STS)-induced apoptosis. Our results for the first demonstrate that ROI-PbFRET method is a powerful potential tool for detecting the dynamics of molecular interactions in live cells.

Recently, we theoretically demonstrate that utilization of silica nanobeads co-doped with Cy3 and Cy5 molecules instead of single dye molecules as fluorescent labels can enable optical resolutions far beyond the diffraction-limit. Here, we show that by combining the 4Pi microscopy and the novel fluorescent label, it is possible to completely suppress the sidelobes in 4Pi focal spot and significantly enhance the optical resolution in the axial direction.

We propose and conduct both the rotating linear polarization imaging (RLPI) and Mueller matrix transformation (MMT) measurements of different biological tissue samples, and testify the capability of the Mueller matrix polarimetry for the anisotropic scattering media. The independent parameters extracted from the RLPI and MMT techniques are compared and analyzed. The tissue experimental results show that the parameters are closely related to the structural characteristics of the turbid scattering media, including the sizes of the scatterers, the angular distribution and order of alignment of the fibers. The results and conclusions in this paper may provide a potential method for the detection of precancerous and early stage cancerous tissues. Also, such studies represent the Mueller matrix transformation procedure which results in a set of parameters linking up the Mueller matrix elements to the structural and optical properties of the media.

Background and aims: The spectral properties of enhanced green fluorescent protein (EGFP) used in current visualizable animal models for nasopharyngeal carcinoma (NPC) result in a limited imaging depth. Far-red fluorescent proteins have optimal spectral wavelengths that allow deep tissue penetration, thus are well-suited for the imaging of tumor growth and metastases in live animals. This study aims to establish an imageable animal model of NPC using far-red fluorescent proteins. Methods: Eukaryotic expression vectors of far-red fluorescent proteins, mLumin and Katushka S158A, were separately transfected into 5-8F NPC cells, and cell lines stably expressing the far-red fluorescent proteins were obtained. These cells were intraperitoneally or intravenously injected into mice, and their tumorigenic and metastatic potential were examined through fluorescence imaging. Finally, factors affecting their tumorigenic ability were further assessed through testing side population (SP) cells proportion by flow cytometry. Results: NPC cell line with high tumorigenicity and metastasis (5-8F-mL2) was screened out, which stably expressed far-red fluorescent protein. Intraperitoneal and intravenous injection of 5-8F-mL2 cells resulted in an abdomen metastasis model and a lung metastasis model. In addition, NPC cell line without tumorigenicity (5-8F-Katushka S158A) was screened out. The percentage of SP cells between 5-8F-mL2 and 5-8F-Katushka S158A was found different, suggesting that the SP cell proportion may play a key role in the determination of cell tumorigenic ability. Conclusion: We successfully established animal models for NPC with high tumorigenicity and metastasis using a super-bright far-red fluorescent protein. Owing to the super-brightness and excellent wavelength parameters, these models may be applied as useful tools for intuitive and efficient monitoring of tumor growth and metastasis, as well as assessing the efficacy of nasopharyngeal cancer drugs.

Challenges remain in imaging fast biological processes in vivo with fluorescence molecular tomography (FMT) due to the long data acquisition time. Data acquisition with limited projections can greatly reduce the time consumption, but the influence of limited-projection on reconstruction quality is currently unclear. Both numerical simulations and a phantom experiment are conducted to analyze this problem. Through a systematic investigation of all the results reconstructed from different numbers of projections, we evaluate the influence of limited-projection data on FMT. A mouse experiment is also performed to validate our work. A general relationship between the number of projections and reconstruction quality is obtained which indicates that the projection number of three is preferred for fast FMT experiment.

A technical feasibility of autofluorescence ductoscopy in breast milk ducts as blood vessels phantoms has been assessed as successful. Malignant tumor can be clearly identified through the milk ducts. We also present the operation principle as well as the preliminary experimental results of a new type of microsize multicore fiber that enables imaging through blood vessel phantoms. Imaging of a manipulated microwire through a drilled phantom is presented.