Highly sensitive SERS analysis of the cyclic Arg–Gly–Asp peptide ligands of cells using nanogap antennas

The cyclic RGD (cRGD) peptide ligands of cells have become widely used for treating several cancers. We report a highly sensitive analysis of c(RGDfC) using surface enhanced Raman spectroscopy (SERS) using single dimer nanogap antennas in aqueous environment. Good agreement between characteristic peaks of the SERS and the Raman spectra of bulk c(RGDfC) with its peptide's constituents were observed. The exhibited blinking of the SERS spectra and synchronization of intensity fluctuations, suggest that the SERS spectra acquired from single dimer nanogap antennas was dominated by the spectrum of single to a few molecules. SERS spectra of c(RGDfC) could be used to detect at the nanoscale, the cells' transmembrane proteins binding to its ligand.

Understanding the interactions of different cancer's cell ligand-receptor constitutes a major challenge for biophotonics research. Using Surface Enhanced Raman Spectroscopy (SERS) the current study experimentally investigates the extracellular matrix (ECM) ligand: Arg–Gly–Asp (RGD) in its cyclic configuration, using the high spatial resolution provided by a single gold plasmonic nanogap antenna. The SERS spectrum of the polypeptide used in multiple drug delivery systems is presented and analysed in details.

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Multiparametric evaluation of hindlimb ischemia using time-series indocyanine green fluorescence imaging

Peripheral arterial disease (PAD) can further cause lower limb ischemia. Quantitative evaluation of the vascular perfusion in the ischemic limb contributes to diagnosis of PAD and preclinical development of new drug. In vivo time-series indocyanine green (ICG) fluorescence imaging can noninvasively monitor blood flow and has a deep tissue penetration. The perfusion rate estimated from the time-series ICG images is not enough for the evaluation of hindlimb ischemia. The information relevant to the vascular density is also important, because angiogenesis is an essential mechanism for post-ischemic recovery. In this paper, a multiparametric evaluation method is proposed for simultaneous estimation of multiple vascular perfusion parameters, including not only the perfusion rate but also the vascular perfusion density and the time-varying ICG concentration in veins. The target method is based on a mathematical model of ICG pharmacokinetics in the mouse hindlimb. The regression analysis performed on the time-series ICG images obtained from a dynamic reflectance fluorescence imaging system. The results demonstrate that the estimated multiple parameters are effective to quantitatively evaluate the vascular perfusion and distinguish hypo-perfused tissues from well-perfused tissues in the mouse hindlimb. The proposed multiparametric evaluation method could be useful for PAD diagnosis.

Perfusion rate, vascular perfusion density and time-varying ICG concentration in veins are estimated simultaneously to quantitatively evaluate and compare the vascular perfusion of the normal and ischemic hindlimbs using time-series ICG imaging, which can monitor blood perfusion in vivo. These parameters may provide more effective information for diagnosis of vascular occlusive disease.

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Feasibility of photoacoustic evaluations on dual-thermal treatment of ex vivo bladder tumors

A variety of thermal therapeutic methods have been investigated to treat bladder tumors but often cause bowel injury and bladder wall perforation due to high treatment dosage and limited clinical margins. The objective of the current study is to develop a dual-thermal modality to deeply coagulate the bladder tumors at low thermal dosage and to evaluate therapeutic outcomes with high contrast photoacoustic imaging (PAI). High intensity focused ultrasound (HIFU) is combined with 532 nm laser light to enhance therapeutic depth during thermal treatments on artificial tumor-injected bladder tissue ex vivo. PAI is employed to identify the margins of the tumors pre- and post-treatments. The dual-thermal modality achieves 3- and 1.8-fold higher transient temperature changes and 2.2- and 1.5-fold deeper tissue denaturation than laser and HIFU, respectively. PAI vividly identifies the position of the injected tumor and entails approximately 7.9 times higher image contrast from the coagulated tumor as that from the untreated tumor. Spectroscopic analysis exhibits that both 740 nm and 760 nm attains the maximum photoacoustic amplitudes from the treated areas. The proposed PAI-guided dual-thermal treatments (laser and HIFU) treatments can be a feasible therapeutic modality to treat bladder tumors in a controlled and efficient manner.

This paper introduces the feasible application of photoacoustic imaging (PAI) for laser-integrated high intensity focused ultrasound (HIFU) treatment on ex vivo bladder tissue injected with artificial tumor. Due to additive thermal effects at low power levels, the proposed thermal treatment coagulates the targeted tissue. PAI ostensibly identifies the locations of both the artificial and the coagulated tumors with high image contrast. The PAI-guided dual thermal treatments can be a feasible therapeutic modality to treat bladder tumors in an effective manner.

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Photosensitized singlet oxygen generation and detection: Recent advances and future perspectives in cancer photodynamic therapy

Photodynamic therapy (PDT) uses photosensitizers and visible light in combination with molecular oxygen to produce reactive oxygen species (ROS) that kill malignant cells by apoptosis and/or necrosis, shut down the tumor microvasculature and stimulate the host immune system. The excited singlet state of oxygen (¹O₂) is recognized to be the main cytotoxic ROS generated during PDT for the majority of photosensitizers used clinically and for many investigational new agents, so that maximizing its production within tumor cells and tissues can improve the therapeutic response, and several emerging and novel approaches for this are summarized. Quantitative techniques for ¹O₂ production measurement during photosensitization are also of immense importance of value for both preclinical research and future clinical practice. In this review, emerging strategies for enhanced photosensitized ¹O₂ generation are introduced, while recent advances in direct detection and imaging of ¹O₂ luminescence are summarized. In addition, the correlation between cumulative ¹O₂ luminescence and PDT efficiency will be highlighted. Meanwhile, the validation of ¹O₂ luminescence dosimetry for PDT application is also considered. This review concludes with a discussion on future demands of ¹O₂ luminescence detection for PDT dosimetry, with particular emphasis on clinical translation.

In order to establish robust individualized singlet oxygen luminescence dosimetry for cancer photodynamic therapy, the most recent advances and future perspectives on enhanced generation and direct detection of singlet oxygen are discussed, and in addition the correlation between cumulative singlet oxygen luminescence and photodynamic therapy efficiency will be highlighted.

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The Impact of Media Multitasking on the Cognitive and Attitudinal Responses to Television Commercials: The Moderating Role of Type of Advertising Appeal

In two studies, we explored the effect of media multitasking on viewers' cognitive and attitudinal responses to television commercials and the moderating role of advertising appeals. The limited capacity theory of Lang (2001) that integrates both the motivational and cognitive ability aspects of information processing was used as the theoretical framework. The results of Study 1 show that in line with previous findings, media multitasking negatively affects cognitive responses but has an overall positive effect on attitudinal responses to television commercials. The results of Study 2 suggest that this effect on attitudinal responses is only present for commercials that focus on the desirability (compared to the feasibility) of a product. The results indicate that in media multitasking contexts, television commercials that rely primarily on stressing the desirability of a product have both a cognitive and an attitudinal advantage compared to those that rely primarily on stressing the feasibility of a product.

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The impact of media multitasking on the cognitive and attitudinal responses to television commercials: the moderating role of type of advertising appeal

In two studies, we explored the effect of media multitasking on viewers' cognitive and attitudinal responses to television commercials and the moderating role of advertising appeals. The limited capacity theory of Lang (2001) that integrates both the motivational and cognitive ability aspects of information processing was used as the theoretical framework. The results of Study 1 show that in line with previous findings, media multitasking negatively affects cognitive responses but has an overall positive effect on attitudinal responses to television commercials. The results of Study 2 suggest that this effect on attitudinal responses is only present for commercials that focus on the desirability (compared to the feasibility) of a product. The results indicate that in media multitasking contexts, television commercials that rely primarily on stressing the desirability of a product have both a cognitive and an attitudinal advantage compared to those that rely primarily on stressing the feasibility of a product.

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La condición de experto médico-pedagógico en Ovide Decroly

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