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1.
J Biomed Opt ; 29(7): 076502, 2024 Jul.
Article in English | MEDLINE | ID: mdl-39006313

ABSTRACT

Significance: In in-line digital holographic microscopy (DHM), twin-image artifacts pose a significant challenge, and reduction or complete elimination is essential for object reconstruction. Aim: To facilitate object reconstruction using a single hologram, significantly reduce inaccuracies, and avoid iterative processing, a digital holographic reconstruction algorithm called phase-support constraint on phase-only function (PCOF) is presented. Approach: In-line DHM simulations and tabletop experiments employing the sliding-window approach are used to compute the arithmetic mean and variance of the phase values in the reconstructed image. A support constraint mask, through variance thresholding, effectively enabled twin-image artifacts. Results: Quantitative evaluations using metrics such as mean squared error, peak signal-to-noise ratio, and mean structural similarity index show PCOF's superior capability in eliminating twin-image artifacts and achieving high-fidelity reconstructions compared with conventional methods such as angular spectrum and iterative phase retrieval methods. Conclusions: PCOF stands as a promising approach to in-line digital holographic reconstruction, offering a robust solution to mitigate twin-image artifacts and enhance the fidelity of reconstructed objects.


Subject(s)
Algorithms , Artifacts , Holography , Image Processing, Computer-Assisted , Holography/methods , Image Processing, Computer-Assisted/methods , Signal-To-Noise Ratio , Microscopy/methods
2.
Micromachines (Basel) ; 14(12)2023 Dec 05.
Article in English | MEDLINE | ID: mdl-38138375

ABSTRACT

We investigate the plasmon coupling of gold nanoparticle (AuNP) dimers dispersed in a nematic liquid crystal matrix using the polarization z-scan technique. Our experimental setup includes the precise control of incident light polarization through polarization angles of 0°, 45°, and 90°. Two distinct cell orientations are examined: parallel and twisted nematic cells. In parallel-oriented cells, where liquid crystal molecules and AuNPs align with the rubbing direction, we observe a remarkable 2-3-fold increase in the nonlinear absorption coefficient when the polarization of the incident light is parallel to the rubbing direction. Additionally, a linear decrease in the third-order nonlinear absorption coefficient is noted as the polarization angle varies from 0° to 90°. In the case of twisted nematic cells, the NPs do not have any preferred orientation, and the enhancement remains consistent across all polarization angles. These findings conclusively establish that the observed enhancement in the nonlinear absorption coefficient is a direct consequence of plasmon coupling, shedding light on the intricate interplay between plasmonic nanostructures and liquid crystal matrices.

3.
Nanotechnology ; 34(36)2023 Jun 27.
Article in English | MEDLINE | ID: mdl-37285825

ABSTRACT

We report structural and nonlinear optical properties of 20 nm gold (Au) nanoparticles (NPs) that are dispersed in planar degenerate (non-oriented) and planar oriented nematic liquid crystals (LCs) (4'-Pentyl-4-biphenylcarbonitrile-5CB). Taking advantage of elastic forces in the planar oriented nematic LC, we aligned AuNPs parallel to the 5CB director axis. In the case of planar degenerate, 5CB is not aligned and has no preferred orientation, forcing the AuNPs to disperse randomly. Results show that the linear optical absorption coefficient for the planar oriented 5CB/AuNPs mixture is larger than the corresponding planar degenerate sample. The nonlinear absorption coefficients are greatly enhanced in planar oriented samples at relatively high concentrations which can be attributed to plasmon coupling between the aligned AuNPs. This study demonstrates the utility of LCs for developing the assembly of NPs with enhanced optical properties which may offer important insight and technological advancement for novel applications, including photonic nanomaterials and optoelectronic devices.

4.
Photochem Photobiol ; 99(2): 547-561, 2023 Mar.
Article in English | MEDLINE | ID: mdl-36103615

ABSTRACT

The electronic and photophysical properties for a series of ruthenium(II) polypyridyl dyes are presented where a π-accepting 5-(vinyl-cyanine)-8-oxyquinolate class of ligand is incorporated to yield an improved vis-NIR absorption. A combination of computational, UV-vis-NIR absorption, phosphorescence emission and cyclic voltammetry studies are used to probe the influence of these ligands on complex electronic and photophysical properties. To assess their potential as vis-NIR photoacoustic contrast agents, select complexes were formulated in a PBS buffer/Tween® 20 solvent system. The p-quinolin-1-ium, 1,3,3-trimethyl-3H-indol-1-ium and 1,1,3-trimethyl-1H-benzo[e]indol-3-ium acceptor groups each impart a strong 680 nm optical absorption and photoacoustic emission on par with the performance exhibited by both the methylene blue and cryptocyanine commercial dyes.

5.
Photochem Photobiol ; 98(1): 62-72, 2022 01.
Article in English | MEDLINE | ID: mdl-33811760

ABSTRACT

The photophysical and electrochemical properties for a series of BODIPY dyes with incremental 3- and 3,5-vinyl conjugation, as well as incremental electron-donating groups (anisole < triphenylamine < ferrocenyl), are presented. Insight into the influence of each vinyl-conjugated electron-donating group on both vis-NIR absorption and fluorescence emission properties is provided. These trends are further corroborated by density functional theory computational analysis. Two of this series containing the 3,5-bis(vinyltriphenylamine) and 3,5-bis(vinylferrocenyl) substituents exhibit significant absorption cross sections in the biological transparency window justifying further investigation of their photoacoustic emission properties via both optical photoacoustic z-scan and photoacoustic tomography experiments. Both the 3,5-bis(vinyltriphenylamine) and 3,5-bis(vinylferrocenyl) substituted BODIPY dyes exhibit quantitative photoacoustic quantum yields. Relative to the commercially available methylene blue and indocyanine green molecular photoacoustic contrast agents, the 3,5-bis(vinyltriphenylamine)-derived BODIPY exhibits the greatest photoacoustic emission and contrast upon excited-state absorption at 685 nm excitation at a low power laser fluence (<20 mJ cm-2 ).


Subject(s)
Boron Compounds , Contrast Media , Boron Compounds/chemistry , Coloring Agents/chemistry , Contrast Media/chemistry , Spectrometry, Fluorescence
6.
ACS Appl Mater Interfaces ; 11(16): 14588-14596, 2019 Apr 24.
Article in English | MEDLINE | ID: mdl-30977626

ABSTRACT

The effect of matrix metalloproteinases (MMPs) on preformed protein coronas around spherical gold nanoparticles (AuNPs) was studied. Protein coronas of different compositions (human serum, human serum albumin, and collagen IV) were formed around AuNPs and characterized. The protease MMP-9 had different effects on the corona depending on the corona composition, resulting in different changes to the corona hydrodynamic diameter ( DH). When incubated with PANC-1 cells, the corona showed evidence of both increases as well as decreases in DH. Varying the composition of the corona influenced the MMP-9 activity. Furthermore, the corona was influenced not only by the protease activity of the MMP-9 but also by its ability to exchange with proteins in the preformed corona. This exchange could also occur with proteins in the media. Thus, the net effect of the MMP-9 was a combination of the MMP-9 protease activity and also exchange. Time scales for the exchange varied depending on the nature that make up the protein corona (weakly vs strongly bound corona proteins). Mass spectrometry was used to probe the protein corona composition and supported the exchange and degradation model. Together, these results indicate that the mechanism of protease activity on AuNP coronas involves both rearrangement and exchange, followed by degradation.


Subject(s)
Blood Proteins/chemistry , Matrix Metalloproteinase 9/metabolism , Metal Nanoparticles/chemistry , Neoplasm Proteins/metabolism , Neoplasms/enzymology , Protein Corona/chemistry , Cell Line, Tumor , Humans , Matrix Metalloproteinase 9/chemistry , Neoplasms/pathology
7.
Photochem Photobiol ; 95(1): 280-292, 2019 01.
Article in English | MEDLINE | ID: mdl-29989174

ABSTRACT

The synthesis, photophysical and photoacoustic characterization for a series of nine π-extended quadrupolar curcumin dyes is presented. A systematic evaluation of the π-bridging unit including the p-phenyl, naphth-4-yl, thien-2-yl and hybrid 4-naphthathien-2-yl groups is presented. Furthermore, evaluation of the strongly donating donor-π-acceptor-π-donor quadrupolar dimethylamino terminated derivatives is also included. Select dyes exhibit excited state absorption at increased laser fluence which translates to the production of a nonlinear enhanced photoacoustic response. In particular, the bis-4-dimethylaminonaphtha-2-thien-5-yl curcuminBF2 contrast agent DMA-5 exhibits an excellent molar photoacoustics (PA) emission at both low (9.4 × 103  V M-1 ) and high (1.47 × 105  V M-1 ) laser fluence which is confirmed by its strong contrast by photoacoustic tomography (PAT). In summary, the strong absorbance and enhanced photoacoustic properties of naphthyl and thienyl curcuminoids here presented provides great promise for future photoacoustic imaging applications as demonstrated by preliminary PAT studies.


Subject(s)
Coloring Agents/chemistry , Curcumin/chemistry , Density Functional Theory , Electrons , Photoacoustic Techniques , Proton Magnetic Resonance Spectroscopy , Spectrometry, Fluorescence , Spectrometry, Mass, Electrospray Ionization
8.
Chem Commun (Camb) ; 54(49): 6352-6355, 2018 Jun 14.
Article in English | MEDLINE | ID: mdl-29868656

ABSTRACT

The synthesis and characterization of a bis(2-dimethylaminothien-5-yl)curcumin boron difluoride chromophore is presented. Photophysical, electrochemical and computational investigations establish the properties of its absorption in the Vis-NIR spectral range relative to established curcumin dyes. Application of this thienyl curcumin dye as a photoacoustic contrast agent is investigated against the dicarbocyanine Cy5 dye in the 675-735 nm excitation range.

9.
Eur J Neurosci ; 47(8): 994-1002, 2018 04.
Article in English | MEDLINE | ID: mdl-29461650

ABSTRACT

In humans and animal models, sex differences are reported for anxiety-like behavior and response to anxiogenic stimuli. In the current work, we studied anxiety-like behavior and response to the prototypical anti-anxiety drug, diazepam. We used 6th generation outbred lines of adult Long Evans rats with high and low anxiety-like behavior phenotypes to investigate the impact of proestrus on the baseline and diazepam-induced behavior. At three doses of diazepam (0, 0.1, and 1.0 mg/kg, i.p.), we measured anxiogenic responses on the elevated plus maze of adult male and female rats. We assessed parvalbumin and brain-derived neurotrophin protein levels in forebrain and limbic structures implicated in anxiety/stress using immunohistochemistry. At baseline, we saw significant differences between anxiety lines, with high anxiety lines displaying less time on the open arms of the elevated plus maze, and less open arm entries, regardless of sex. During proestrus, high anxiety females showed less anxiety-like behavior at 0.1 mg/kg, while low anxiety females displayed less anxiety-like behavior at 0.1 and 1.0 doses, relative to males. Brain-derived neurotrophin protein was elevated in females in the medial prefrontal cortex and central amygdala, while parvalbumin-immunoreactive cells were greater in males in the medial prefrontal cortex. Parvalbumin-positive cells in high anxiety females were higher in CA2 and dentate gyrus relative to males from the same line. In sum, when tested in proestrus, females showed greater anxiolytic effects of diazepam relative to males, and this correlated with increases in neurotrophin and parvalbumin neuron density in corticolimbic structures.


Subject(s)
Anti-Anxiety Agents/pharmacology , Behavior, Animal , Brain-Derived Neurotrophic Factor/metabolism , Diazepam/pharmacology , Neurons/metabolism , Parvalbumins/metabolism , Sex Characteristics , Animals , Animals, Inbred Strains , Brain/metabolism , Dose-Response Relationship, Drug , Female , Male , Proestrus , Rats
10.
Chemistry ; 24(4): 906-917, 2018 Jan 19.
Article in English | MEDLINE | ID: mdl-29149546

ABSTRACT

The synthesis and characterization of a series of donor-π-acceptor-π-donor (D-A-D) curcuminoid molecules is presented herein that incorporates π-extended aryl and electron-donating amino terminal functionalization. Computational evaluation shows these molecules possess quadrupolar character with the lowest energy transitions displaying high molar extinction coefficients with broad tunability through manipulation of terminal donating groups. Consistent with their quadrupolar nature, these molecules show varying degrees of solvatochromic behavior in both their absorption and emission spectra, which has been analyzed by Lippert-Mataga and Kamlet-Taft analysis. Photophysical and photoacoustic (PA) properties of these molecules have been investigated by the optical photoacoustic z-scan (OPAZ) method. Selected curcuminoid molecules display nonlinear behavior at a high laser fluence through excited state absorption that translates to the production of an enhanced photoacoustic emission. A relative comparison of "molar PA emission" is also presented with the crystal violet linear optical absorbing/linear PA emitting system being utilized as a standard reference material for OPAZ experiments. Furthermore, PA tomography experiments are presented to illustrate the enhanced PA contrast obtainable via an excited state absorption.

11.
J Biomed Opt ; 19(11): 116001, 2014.
Article in English | MEDLINE | ID: mdl-25364948

ABSTRACT

We report the use of digital holographic microscopy (DHM) as a viable microscopy approach for quantitative, nondestructive longitudinal imaging of in vitro three-dimensional (3-D) tumor models. Following established methods, we prepared 3-D cultures of pancreatic cancer cells in overlay geometry on extracellular matrix beds and obtained digital holograms at multiple time points throughout the duration of growth. The holograms were digitally processed and the unwrapped phase images were obtained to quantify the nodule thickness over time under normal growth and in cultures subject to chemotherapy treatment. In this manner, total nodule volumes are rapidly estimated and demonstrated here to show contrasting time-dependent changes during growth and in response to treatment. This work suggests the utility of DHM to quantify changes in 3-D structure over time and suggests the further development of this approach for time-lapse monitoring of 3-D morphological changes during growth and in response to treatment that would otherwise be impractical to visualize.


Subject(s)
Antineoplastic Agents/pharmacology , Holography/methods , Imaging, Three-Dimensional/methods , Microscopy/methods , Models, Biological , Neoplasms , Antineoplastic Agents/therapeutic use , Cell Line, Tumor , Humans , Neoplasms/drug therapy , Neoplasms/pathology , Organoplatinum Compounds/pharmacology , Organoplatinum Compounds/therapeutic use , Oxaliplatin
12.
J Am Chem Soc ; 136(45): 15853-6, 2014 Nov 12.
Article in English | MEDLINE | ID: mdl-25329769

ABSTRACT

A first approach toward understanding the targeted design of molecular photoacoustic contrast agents (MPACs) is presented. Optical and photoacoustic Z-scan spectroscopy was used to identify how nonlinear (excited-state) absorption contributes to enhancing the photoacoustic emission of the curcuminBF2 and bis-styryl (MeOPh)2BODIPY dyes relative to Cy3.


Subject(s)
Absorption, Physicochemical , Boron Compounds/chemistry , Contrast Media/chemistry , Optical Imaging/methods , Photoacoustic Techniques/methods , Coloring Agents/chemistry , Drug Design
13.
Chem Phys Lett ; 608: 303-307, 2014 Jul 21.
Article in English | MEDLINE | ID: mdl-25242819

ABSTRACT

The nonlinear optical properties of a series of pyrrolic compounds consisting of BODIPY and aza-BODIPY systems are investigated using 532 nm nanosecond laser and the Z-scan technique. Results show that 3,5-distyryl extension of BODIPY to the red shifted MeO2BODIPY dye has a dramatic impact on its nonlinear absorption properties changing it from a saturable absorber to an efficient reverse saturable absorbing material with a nonlinear absorption coefficient of 4.64 × 10-10 m/W. When plotted on a concentration scale per mole of dye in solution MeO2BODIPY far outperforms the recognized zinc(II) phthalocyanine dye and is comparable to that of zinc(II) tetraphenylporphyrin.

14.
Pharmacol Biochem Behav ; 124: 326-32, 2014 Sep.
Article in English | MEDLINE | ID: mdl-24999221

ABSTRACT

Sex differences have been noted in patterns of drug use and relapse, and in particular with amphetamine abuse, implicating estradiol in mediating female neurobehavioral responses. To investigate the interaction of estradiol with amphetamine-induced hyperactivity, we compared male, intact female (INTACT), ovariectomized (OVX) and ovariectomized estradiol-treated (OVX+EB) female rats receiving repeated amphetamine (AMPH) treatment. All rats received intermittent AMPH injections for three days, and baseline and post-injection locomotor activity as well as fine-motor movements were recorded. Upon completion of behavioral experiments, immunohistochemistry was performed to assess parvalbumin-immunoreactive (PV-IR) GABAergic neurons in the medial prefrontal cortex (mPFC). Results indicate that AMPH induced greater behavioral response during habituation among the INTACT animals, and post-injection hyperactivity was apparent on days 2 and 3, among INTACT and OVX+EB females. For INTACT animals, the hyperactivity was most pronounced when estrogen levels were high. Immunohistochemical analysis using digital holographic microscopy revealed INTACT and OVX+EB females had less expression and smaller somatic area of PV-IR neurons in the mPFC. These data provide evidence for rapid development of sex differences in response to AMPH that correlates with sexually dimorphic alterations in a subset of mPFC GABAergic neurons implicated in modulating forebrain dopamine projections.


Subject(s)
Amphetamines/pharmacology , Microscopy/methods , Neurons/drug effects , Prefrontal Cortex/drug effects , Sex Factors , gamma-Aminobutyric Acid/metabolism , Animals , Female , Male , Neurons/metabolism , Prefrontal Cortex/cytology , Prefrontal Cortex/metabolism , Rats , Rats, Long-Evans
15.
Opt Commun ; 285(24): 4954-5960, 2012 Nov 01.
Article in English | MEDLINE | ID: mdl-23109732

ABSTRACT

We present a digital holography microscopy technique based on parallel-quadrature phase-shifting method. Two π/2 phase-shifted holograms are recorded simultaneously using polarization phase-shifting principle, slightly off-axis recording geometry, and two identical CCD sensors. The parallel phase-shifting is realized by combining circularly polarized object beam with a 45° degree polarized reference beam through a polarizing beam splitter. DC term is eliminated by subtracting the two holograms from each other and the object information is reconstructed after selecting the frequency spectrum of the real image. Both amplitude and phase object reconstruction results are presented. Simultaneous recording eliminates phase errors caused by mechanical vibrations and air turbulences. The slightly off-axis recording geometry with phase-shifting allows a much larger dimension of the spatial filter for reconstruction of the object information. This leads to better reconstruction capability than traditional off-axis holography.

16.
Appl Opt ; 51(9): 1387-95, 2012 Mar 20.
Article in English | MEDLINE | ID: mdl-22441487

ABSTRACT

We present detailed theoretical evaluation and thorough experimental investigation of quantitative phase imaging using our previously demonstrated dual-plane in-line digital holographic microscopy technique [Opt. Lett. 35, 3426 (2010)]. This evaluation is based on the recording of two interferograms at slightly different planes and numerically reconstructing the object information. The zero-order diffracted wave is eliminated by using the method of subtraction of average intensity of the entire hologram, and the twin-image diffracted wave is removed by Fourier domain processing of the two recorded holograms. Experiments are performed using controlled amplitude and phase objects and human muscle cells to demonstrate the potential of this technique.


Subject(s)
Holography/methods , Image Enhancement/methods , Microscopy/methods , Algorithms , Computer Simulation , Equipment Design , Humans , Myocytes, Smooth Muscle/ultrastructure
17.
Opt Commun ; 285(21-22): 4262-4267, 2012 Oct 01.
Article in English | MEDLINE | ID: mdl-23471012

ABSTRACT

We present a robust encryption method for the encoding of 2D/3D objects using digital holography and virtual optics. Using our recently developed dual-plane in-line digital holography technique, two in-line digital holograms are recorded at two different planes and are encrypted using two different double random phase encryption configurations, independently. The process of using two mutually exclusive encryption channels makes the system more robust against attacks since both the channels should be decrypted accurately in order to get a recognizable reconstruction. Results show that the reconstructed object is unrecognizable even when the portion of the correct phase keys used during decryption is close to 75%. The system is verified against blind decryptions by evaluating the SNR and MSE. Validation of the proposed method and sensitivities of the associated parameters are quantitatively analyzed and illustrated.

18.
Opt Lett ; 35(20): 3426-8, 2010 Oct 15.
Article in English | MEDLINE | ID: mdl-20967088

ABSTRACT

We report a dual plane in-line digital holographic microscopy technique that exploits the method of subtraction of average intensity of the entire hologram to suppress the zero-order diffracted wave. Two interferograms are recorded at different planes to eliminate the conjugate image. The experimental results demonstrate successful reconstruction of phase objects as well as of amplitude objects. The two interferograms can be recorded simultaneously, using two CCD or CMOS sensors, in order to increase the acquisition rate. This enhanced acquisition rate, together with the improved reconstruction capability of the proposed method, may find applications in biomedical research for visualization of rapid dynamic processes at the cellular level.


Subject(s)
Holography/methods , Image Processing, Computer-Assisted/methods , Microscopy/methods , Algorithms , Equipment Design , Image Enhancement/methods , Image Interpretation, Computer-Assisted/methods , Interferometry/methods , Signal Processing, Computer-Assisted
19.
Opt Express ; 18(9): 9020-5, 2010 Apr 26.
Article in English | MEDLINE | ID: mdl-20588748

ABSTRACT

We report a novel photoacoustic Z-scan (PAZ-scan) technique that combines the advantages offered by the conventional Z-scan method and the sensitivity of the photoacoustic detection. The sample is scanned through the focused laser beam and the generated photoacoustic signal is recorded using a 10 MHz focused ultrasound transducer. Since the signal strength is directly proportional to the optical absorption, PAZ-scan displays nonlinear behavior depicting the nonlinear optical absorption of the material. Among many advantages, our experiments on mouse blood show that PAZ-scan can potentially be used as a standard technique to calibrate contrast agents used in theranostics in general and photoacoustics in particular.

20.
Opt Lett ; 34(8): 1243-5, 2009 Apr 15.
Article in English | MEDLINE | ID: mdl-19370131

ABSTRACT

We have developed a common-path multimodal optical microscopy system that is capable of using a single optical source and a single camera to image amplitude, phase, and fluorescence features of a biological specimen. This is achieved by varying either contrast enhancement filters at the Fourier plane and/or neutral density/fluorescence filters in front of the CCD camera. The feasibility of the technique is demonstrated by obtaining brightfield, fluorescence, phase-contrast, spatially filtered, brightfield+fluorescence, phase+fluorescence, and edge-enhanced+fluorescence images of the same Drosophila embryo without the need for image registration and fusion. This comprehensive microscope has the capability of providing both structural and functional information and may be used for applications such as studying live-cell dynamics and in high throughput microscopy and automated microscopy.


Subject(s)
Microscopy/methods , Optical Phenomena , Absorption , Animals , Drosophila/embryology , Fluorescence
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