Next-Generation Reconfigurable Nanoantennas and Polarization of Light.

This study is aimed at the design, calibration, and development of a near-infrared (NIR) liquid crystal multifunctional automated optical polarimeter, which is aimed at the study and characterization of the polarimetric properties of polymer optical nanofilms. The characterization of these novel nanophotonic structures has been achieved, in terms of Mueller matrix and Stokes parameter analyses. The nanophotonic structures of this study consisted of (a) a matrix consisting of two different polymer domains, namely polybutadiene (PB) and polystyrene (PS), functionalized with gold nanoparticles; (b) cast and annealed Poly (styrene-b-methyl methacrylate) (PS-PMMA) diblock copolymers; (c) a matrix of a block copolymer (BCP) domain, PS-b-PMMA or Poly (styrene-block-methy methacrylate), functionalized with gold nanoparticles; and (d) different thicknesses of PS-b-P2VP diblock copolymer functionalized with gold nanoparticles. In all cases, backscattered infrared light was studied and related to the polarization figures-of-merit (FOM). The outcome of this study indicates that functionalized polymer nanomaterials, depending upon their structure and composition, exhibit promising optical characteristics, modulating and manipulating the polarimetric properties of light. The fabrication of technologically useful, tunable, conjugated polymer blends with an optimized refractive index, shape, size, spatial orientation, and arrangement would lead to the development of new nanoantennas and metasurfaces.

Transcranial near-infrared light in treatment of neurodegenerative diseases.

Light is a natural agent consisting of a range of visible and invisible electromagnetic spectrum travels in waves. Near-infrared (NIR) light refers to wavelengths from 800 to 2,500 nm. It is an invisible spectrum to naked eyes and can penetrate through soft and hard tissues into deep structures of the human body at specific wavelengths. NIR light may carry different energy levels depending on the intensity of emitted light and therapeutic spectrum (wavelength). Stimulation with NIR light can activate intracellular cascades of biochemical reactions with local short- and long-term positive effects. These properties of NIR light are employed in photobiomodulation (PBM) therapy, have been linked to treating several brain pathologies, and are attracting more scientific attention in biomedicine. Transcranial brain stimulations with NIR light PBM in recent animal and human studies revealed a positive impact of treatment on the progression and improvement of neurodegenerative processes, management of brain energy metabolism, and regulation of chronic brain inflammation associated with various conditions, including traumatic brain injury. This scientific overview incorporates the most recent cellular and functional findings in PBM with NIR light in treating neurodegenerative diseases, presents the discussion of the proposed mechanisms of action, and describes the benefits of this treatment in neuroprotection, cell preservation/detoxification, anti-inflammatory properties, and regulation of brain energy metabolism. This review will also discuss the novel aspects and pathophysiological role of the glymphatic and brain lymphatics system in treating neurodegenerative diseases with NIR light stimulations. Scientific evidence presented in this overview will support a combined effort in the scientific community to increase attention to the understudied NIR light area of research as a natural agent in the treatment of neurodegenerative diseases to promote more research and raise awareness of PBM in the treatment of brain disorders.

Prospective Study Comparing Clinical vs Indocyanine Green Fluorescence-Based Assessment of Line of Transection in Robotic Rectal Cancer Surgery-Indian Study.

Anastomotic leakage continues to be the most feared postoperative complications in rectal surgery with negative impact on both short- and long-term outcomes. Fortunately, new surgical strategies have helped to offset this complication and improve surgical outcomes. Traditionally, perfusion is assessed by intraoperative visual judgment by the surgeon. These subjective methods lack predictive accuracy resulting in either excess or insufficient colonic resection. Indocyanine green (ICG) fluorescence has shown promise in identifying the adequacy of perfusion. After injection of ICG, the system projected high-resolution near-infrared real-time images of blood flow in mesentery and bowel wall. This novel imaging method is used intraoperatively for taking real-time informed decisions. We conducted a single institutional prospective study to identify the feasibility of ICG identification of vascularity of anastomotic site and its impact on the change of plan of surgical management in robotic rectal cancer surgery. Between September 2017 and April 2019, fifty patients undergoing robotic rectal cancer surgery were included in the study. The aim was to analyze the feasibility and clinical benefit of intraoperative near-infrared fluorescence imaging in determining the line of transection in comparison with the traditional method. Line of proximal transection of the bowel subjectively assessed by the surgical team was marked point B and that after ICG injection was marked point A if moved proximally and point C if moved distally. The vascular anatomy was clearly identified with no intraoperative or injection-related adverse effects. Of the 50 patients, the line of transaction remained the same in 6 patients (12%). Based on the fluorescence imaging, the surgical team opted for further proximal change of the transection line up to an "adequate" fluorescent portion in 3 patients (6%) and distally in 41 patients (82%). ICG-based infrared image-guided localization gives a real-time image of colon vascularity possibly affecting anastomotic leak. The ICG fluorescence imaging system is a simple, safe, and useful technique, performed within a short time, and it enables visual evaluation of the blood flow in the intestinal tract prior to anastomosis. Larger studies are needed before this can become the standard of care.

Stimuli-responsive Drug Delivery Nanocarriers in the Treatment of Breast Cancer.

Stimuli-responsive drug-delivery nanocarriers (DDNs) have been increasingly reported in the literature as an alternative for breast cancer therapy. Stimuli-responsive DDNs are developed with materials that present a drastic change in response to intrinsic/chemical stimuli (pH, redox and enzyme) and extrinsic/physical stimuli (ultrasound, Near-infrared (NIR) light, magnetic field and electric current). In addition, they can be developed using different strategies, such as functionalization with signaling molecules, leading to several advantages, such as (a) improved pharmaceutical properties of liposoluble drugs, (b) selectivity with the tumor tissue decreasing systemic toxic effects, (c) controlled release upon different stimuli, which are all fundamental to improving the therapeutic effectiveness of breast cancer treatment. Therefore, this review summarizes the use of stimuli-responsive DDNs in the treatment of breast cancer. We have divided the discussions into intrinsic and extrinsic stimuli and have separately detailed them regarding their definitions and applications. Finally, we aim to address the ability of these stimuli-responsive DDNs to control the drug release in vitro and the influence on breast cancer therapy, evaluated in vivo in breast cancer models.

Innovative treatment for hepatocellular carcinoma (HCC).

Indocyanine green (ICG) is not new in the field of liver surgery. Early studies performed in the 1980s and 1990s revealed the value of the ICG clearance test in predicting post-hepatectomy morbidity and mortality. ICG clearance and retention tests are crucial for determining precise liver function before liver surgery and offer several benefits for safe surgery. Whereas ICG is well-known and has long history in medicine, recent progress in infrared light technology over the last decade has highlighted another feature of ICG. For example, ICG fluorescence-guided surgery may change the next generation of liver surgery. In the near future, ICG with near-infrared (NIR) light photodynamic therapy (PDT) is expected to become a new treatment method for hepatocellular carcinoma (HCC). Furthermore, several aspects of the mechanisms of ICG accumulation in HCC cells have been revealed by important basic research studies. New imaging technologies and mechanistic findings keep ICG in the spotlight. In this article, we review three recently described topics of ICG which may contribute to the development of innovative and new treatments method for HCC, fluorescence-guided surgery, mechanism of ICG accumulation in HCC cells, PDT for HCC.

Near-Infrared Light-Excited Upconverting Persistent Nanophosphors in Vivo for Imaging-Guided Cell Therapy.

Optical imaging for biological applications is in need of more sensitive tool. Persistent luminescent nanophosphors enable highly sensitive in vivo optical detection and almost completely avoid tissue autofluorescence. Nevertheless, the actual persistent luminescent nanophosphors necessitate ex vivo activation before systemic operation, which severely restricted the use of long-term imaging in vivo. Hence, we introduced a novel generation of optical nanophosphors, based on (Zn2SiO4:Mn):Y3+, Yb3+, Tm3+ upconverting persistent luminescent nanophosphors; these nanophosphors can be excited in vivo through living tissues by highly penetrating near-infrared light. We can trace labeled tumor therapeutic macrophages in vivo after endocytosing these nanophosphors in vitro and follow macrophages biodistribution by a simple whole animal optical detection. These nanophosphors will open novel potentials for cell therapy research and for a variety of applications in diagnosis in vivo.

Construction of ICG encapsulated W18O49@MSN as a fluorescence carrier for real-time tracked photothermal therapy.

Photothermal therapy (PTT) has drawn tremendous attention because of its high therapeutic efficiency in targeting cells while minimizing the damage to normal tissues and organs. Tungsten oxide (W18O49, WO) plays a pivotal role in PTT development and its use in PTT systems has been extensively studied. However, it is difficult to control morphology of WO through conventional hydrothermal method. Which make its related researches have been limited up to now. In this study, we describe the construction and effects on tumor of a novel nanoplatform based on WO and indocyanine green (ICG) loaded in mesoporous silica nanoparticles (MSN) for dual-modal PTT and near-infrared imaging. (WO+ICG)@MSN could efficiently control WO shape without the need of surface modification due to its water-soluble of MSN. (WO+ICG)@MSN produced a PTT synergistic effect under irradiation of a single 808nm near-infrared (NIR) laser. Notably, an enhanced lethal effect of the 808nm laser triggering dual-modal therapy on B16 tumor cells was observed. The in vivo animal experiments showed that (WO+ICG)@MSN induced an effective solid tumor reduction under 808nm NIR light irradiation, revealing the potential of these nanocomposites as a NIR-mediated dual-modal therapeutic platform for cancer treatment.

Effect of near-infrared light on in vitro cellular ATP production of osteoblasts and fibroblasts and on fracture healing with intramedullary fixation.

OBJECTIVE: Evaluate the effect of near-infrared light (NIR) on immediate production of ATP by osteoblasts and fibroblasts in vitro, and the healing process of rat femur fractures with intramedullary fixation. BACKGROUND: NIR is one potential treatment option for complications of fracture healing, which has shown to stimulate cellular proliferation and to enhance the healing process. METHODS: Cell culture - MC3T3-E1 and 3T3-A31 cells were subjected to NIR at 660 nm, 830 nm, or both combined. ATP was assayed at 5, 10, 20, and 45 min after exposure. Animal study - 18 rats had surgery with retrograde intramedullary pins inserted into their femurs, which then underwent closed, transverse femur fracture. Rats were randomly divided into 3 study groups of 6 each: nonirradiated controls, 660 nm, and 830 nm NIR. Healing process was assessed by a blinded radiologist, assigning a healing score of 1-6 for radiographs taken on days 0, 7, 14, and 21. RESULTS: Cell culture - All groups gave significant increase in ATP within 5-10 min, with decay to baseline by 45 min. 660 nm NIR was significantly more effective than 830 nm with fibroblasts or either wavelength with osteoblasts. Animal study - A significant increase in the fracture healing grade in the 660 nm group at day 14, but with no differences at day 21. CONCLUSION: The study demonstrated an immediate increase in ATP production in vitro and an initial acceleration of callus formation in the fracture healing process, in the presence of NIR.

Persistent Luminescent Nanocarrier as an Accurate Tracker in Vivo for Near Infrared-Remote Selectively Triggered Photothermal Therapy.

Optical imaging-guidance of indocyanine green (ICG) for photothermal therapy (PTT) has great latent capacity in cancer therapy. However, the conventional optical image-guidance mode has caused strong tissue autofluorescence of the living tissue, which leads to the accurate infrared light irradiation cannot be conducted. In this article, ICG and persistent luminescence phosphors (PLPs) coloaded mesoporous silica nanocarriers ((ICG+PLPs)@mSiO2) were first designed and prepared for persistent luminescent imaging-guided PTT. The (ICG+PLPs)@mSiO2 nanocarriers could significantly improve signal-to-noise ratio during luminescence imaging-guided PTT, making the PLP promising for improving the accuracy of the tumor site for photothermal therapy in vivo. This paper is likely to develop a new way for accurately regulating cancer cell death based on luminescence imaging-guided PTT selectively triggered by near-infrared (NIR)-remote.