Verteporfin fluorescence in antineoplastic-treated pancreatic cancer cells found concentrated in mitochondria.

BACKGROUND: Traditional treatments for pancreatic cancer (PC) are inadequate. Photodynamic therapy (PDT) is non-invasive, and proven safe to kill cancer cells, including PC. However, the mitochondrial concentration of the photosensitizer, such as verteporfin, is key. AIM: To investigate the distribution of fluorescence of verteporfin in PC cells treated with antitumor drugs, post-PDT. METHODS: Workable survival rates of PC cells (AsPC-1, BxPC-3) were determined with chemotherapy [doxorubicin (DOX) and gemcitabine (GEM)] and non-chemotherapy [sirolimus (SRL) and cetuximab (CTX)] drugs in vitro, with or without verteporfin, as measured via MTT, flow cytometry, and laser confocal microscopy. Reduced cell proliferation was associated with GEM that was more enduring compared with DOX. Confocal laser microscopy allowed observation of GEM- and verteporfin-treated PC cells co-stained with 4',6-diamidino-2-phenylindole and MitoTracker Green to differentiate living and dead cells and subcellular localization of verteporfin, respectively. RESULTS: Cell survival significantly dropped upon exposure to either chemotherapy drug, but not to SRL or CTX. Both cell lines responded similarly to GEM. The intensity of fluorescence was associated with the concentration of verteporfin. Additional experiments using GEM showed that survival rates of the PC cells treated with 10 µmol/L verteporfin (but not less) were significantly lower relative to nil verteporfin. Living and dead stained cells treated with GEM were distinguishable. After GEM treatment, verteporfin was observed primarily in the mitochondria. CONCLUSION: Verteporfin was observed in living cells. In GEM -treated human PC cells, verteporfin was particularly prevalent in the mitochondria. This study supports further study of PDT for the treatment of PC after neoadjuvant chemotherapy.

Multi-functional device: manipulating linear and circular-polarization conversion in a terahertz chiral metamaterial.

We propose a terahertz chiral metamaterial as a multi-functional device to manipulate asymmetry transmission of linear polarized waves, linear-to-elliptical polarization conversion and circular dichroism in transmission mode while asymmetry reflection of circular polarized waves. For incidence of linear polarized waves, dual-band asymmetry transmission is shown around 0.42 THz and 1.04 THz where asymmetry transmission factors reach up to two peak values: ∼0.51 and ∼0.55, respectively. Intense linear-to-elliptical polarization conversion occurs at 0.81 THz and 0.97 THz, respectively. For incidence of circular polarized waves, a strong circular dichroism appears at 0.36 THz where circular dichroism parameter reaches to ∼0.64 and asymmetry reflection is displayed around 0.36 THz with the maximum of asymmetry reflection factors approaching to 0.55.

Theoretical investigation of a controlled unidirectional reflectionlessness by applying external voltage in an electro-optical plasmonic waveguide system.

We theoretically investigate an controlled unidirectional reflectionlessness and near perfect absorption by applying external voltage in an electro-optical plasmonic waveguide system based on near-field coupling between two resonators. The system consists of two resonators side coupled to a metal-dielectric-metal plasmonic waveguide. Based on the numerical simulation, when external voltage is U = 7.4 V, the reflections for forward and backward directions are close to 0 and 0.82 at frequency 144.18 THz, while the reflections for forward and backward directions are close to 0.81 and 0 at frequency 150.86 THz when external voltage is U = 1.5 V. And the high absorption for forward (backward) direction is ∼0.97 (∼0.99) at frequency 144.18 THz (150.86 THz).

Highly-dispersive unidirectional reflectionless phenomenon based on high-order plasmon resonance in metamaterials.

In this work, we design a structure of metamaterials that consists of double sliver-ring resonators, in which highly-dispersive unidirectional reflectionlessness and absorption are achieved based on high-order plasmon resonance. Reflections of +z and -z directions at 461.34 THz (456.68 THz) are ∼0 (0.82) and ∼0.85 (0) when the distance d=222.9 nm (259.8 nm), respectively. High absorption of ∼0.97 and the quality factor of ∼435 can be obtained in the loss metal structure at room temperature. What's more, unidirectional reflectionlessness is investigated at low temperature.

Dual-band unidirectional reflectionlessness at exceptional points in a plasmonic waveguide system based on near-field coupling between two resonators.

Dual-band unidirectional reflectionlessness at exceptional points is investigated theoretically in a non-Hermitian plasmonic waveguide system, based on near-field coupling by using only two resonators. The system consists of a metal-insulator-metal waveguide end-coupled to two nanohole resonators. The reflectivity for the forward (backward) direction is ∼0 (∼0) at frequency 205.20 THz (194.56 THz), while for the backward (forward) direction it is ∼0.76 (∼0.78). Moreover, the quality factors of the dual-band unidirectional reflectionlessness for forward and backward directions can reach ∼132 and ∼137, respectively.

Dual-Band Unidirectional Reflectionless Propagation in Metamaterial Based on Two Circular-Hole Resonators.

Dual-band unidirectional reflectionless propagation at two exceptional points is investigated in metamaterial, which is composed of only two gold resonators with circular holes, by simply manipulating the angle of incident wave and distance between two resonators. Furthermore, the dual-band unidirectional reflectionless propagation can be realized in the wide ranges of incident angle from 0 ∘ to 50 ∘ and distance from 255 nm to 355 nm between two resonators. In addition, our scheme is insensitive to polarization of incident wave due to the circular-hole structure of the resonators.

Unidirectional reflectionless phenomena in a non-Hermitian quantum system of quantum dots coupled to a plasmonic waveguide.

Unidirectional reflectionless phenomena are investigated theoretically in a non-Hermitian quantum system composed of several quantum dots and a plasmonic waveguide. By adjusting the phase shifts between quantum dots, single- and dual-band unidirectional reflectionlessnesses are realized at exceptional points based on two and three quantum dots coupled to a plasmonic waveguide, respectively. In addition, single- and dual-band unidirectional perfect absorptions with high quality factors are obtained at the vicinity of exceptional points.

Dual-band unidirectional reflectionless phenomena in an ultracompact non-Hermitian plasmonic waveguide system based on near-field coupling.

Dual-band unidirectional reflectionlessness and coherent perfect absorption (CPA) are demonstrated in a non-Hermitian plasmonic waveguide system based on near-field coupling between a single resonator and the resonant modes of two resonators showing an electromagnetically induced-transparency-like (EIT-like) effect. The non-Hermitian plasmonic system consists of three metal-insulator-metal (MIM) resonators coupled to a MIM plasmonic waveguide.

Switching the unidirectional reflectionlessness by polarization in non-ideal PT metamaterial based on the phase coupling.

An effective scheme on switching the exceptional point(EP) where unidirectional reflectionlessness occurs is firstly proposed in non-ideal PT metamaterial via the polarization of incident light. The unidirectional reflectionlessness could be effectively controlled only by adjusting the phase coupling of the two resonators which are consisted of two identical but vertically placed crosses and are excited by incident light as an effective gain. Besides, the unidirectional perfect absorber occurs in the vicinity of EP.

Unidirectional reflectionless propagation in a non-ideal parity-time metasurface based on far field coupling.

We propose a scheme to achieve a controllable unidirectional reflectionless propagation at exceptional point (EP) in a non-ideal parity-time metasurface consisting of two silver ring resonators. The unidirectional reflectionless propagation can be manipulated by simply adjusting the angle of incident wave and the distance s between two silver rings based on the far field coupling. In addition, the angle of incident wave in a wide range of ∼25° is available to achieve the unidirectional reflectionless propagation. Moreover, the unidirectional reflectionless propagation at EP is insensitive to the polarization of incident wave due to the two-ring structure.