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Seol A Jang,&ast; Su Jin Kwon,&ast; Chul Sik Kim, Seok Won Park, Kyoung Min Kim Division of Endocrinology, Department of Internal Medicine, Yongin Severance Hospital, Yonsei University College of Medicine, Yongin, South Korea&ast;These authors contributed equally to this workCorrespondence: Kyoung Min Kim, Division of Endocrinology, Department of Internal Medicine, Yongin Severance Hospital, Yonsei University College of Medicine, Yongin, South Korea, Tel +82 31-5189-8798, Fax +82 31-5189-8567, Email kyoungmin.kim@yonsei.ac.krPurpose: Falls are the leading cause of injury among hospitalized patients, particularly among older patients. We investigated the association between serum phosphate (s-phosphate) levels and the risk of in-hospital falls.Patients and Methods: This retrospective observational cohort study included all patients aged over 50 years who were admitted to Yongin Severance Hospital in South Korea between January 2018 and March 2021. Demographic, anthropometric, and biochemical parameters were recorded on admission. S-phosphate levels were classified into three groups: below normal (< 2.8 mg/dL), normal (2.8– 4.4 mg/dL), and above normal (≥ 4.5 mg/dL). The normal group was further stratified into tertiles (2.8– 3.2, 3.3– 3.7, and 3.8– 4.4 mg/dL). The incidence of in-hospital falls was compared between the five groups. Logistic regression analyses were performed to assess the association between s-phosphate levels and the incidence of falls during the hospital stay, with clinical factors included as covariates in the multivariable models.Results: A total of 15,485 patients (female: 52.1%) with a median age of 70.0 years (interquartile range: 60.0– 79.0 years) were included in the analysis, of whom 295 (1.9%) experienced a fall during the hospital stay. The incidence of falls was significantly higher among patients with lower s-phosphate levels, and this relationship also applied among patients with s-phosphate levels within the normal range as well. The association between lower s-phosphate levels and increased risk of falls remained significant in the adjusted analyses.Conclusion: A lower s-phosphate level on admission was independently associated with an increased risk of in-hospital falls. Further studies are needed to determine whether the s-phosphate level on admission could improve prediction of the risk of in-hospital falls.Keywords: in-hospital falls, older adults, blood biochemistry, risk prediction

Hyo Jung Shin,1,2 Hyewon Park,1,2 Nara Shin,1,2 Juhee Shin,1,2 Do Hyeong Gwon,1,2 Hyeok Hee Kwon,1,3 Yuhua Yin,1,2 Jeong-Ah Hwang,1,2 Jinpyo Hong,2 Jun Young Heo,1,4,5 Cuk-Seong Kim,1,6 Yongbum Joo,7 Youngmo Kim,7 Jinhyun Kim,8 Jaewon Beom,9 Dong Woon Kim1,2 1Department of Medical Science, Chungnam National University College of Medicine, Daejeon 35015, Republic of Korea; 2Department of Anatomy and Cell Biology, Brain Research Institute, Chungnam National University College of Medicine, Daejeon 35015, Republic of Korea; 3Department of Pediatrics; 4Biochemistry; 5Infection Control Convergence Research Center; 6Physiology Chungnam National University College of Medicine, Daejeon, Republic of Korea; 7Department of Orthopedics, Chungnam National University College of Medicine, Daejeon, Republic of Korea; 8Division of Rheumatology, Department of Internal Medicine, Chungnam National University College of Medicine, Daejeon, Republic of Korea; 9Department of Rehabilitation Medicine, Seoul National University Bundang Hospital, Seongnam, Gyeonggi-do, Republic of KoreaCorrespondence: Dong Woon Kim DVM., PhD.Department of Anatomy and Cell Biology, Chungnam National University College of Medicine, 266 Munhwa-Ro, Chung-Gu, Daejeon 35015, Republic of KoreaTel +82-42-580-8201Fax +82-42-586-4800Email visnu528@cnu.ac.krJinhyun Kim, MD., PhD.Department of Internal Medicine, Chungnam National University College of Medicine, 266 Munhwa-Ro, Chung-Gu, Daejeon 35015, Republic of KoreaTel +82-42-338-2420Fax +82-42-586-4800Email jkim@cnuh.co.krBackground: Osteoarthritis (OA) is the most common type of joint disease associated with cartilage breakdown. However, the role played by mitochondrial dysfunction in OA remains inadequately understood. Therefore, we investigated the role played by p66shc during oxidative damage and mitochondrial dysfunction in OA and the effects of p66shc downregulation on OA progression.Methods: Monosodium iodoacetate (MIA), which is commonly used to generate OA animal models, inhibits glycolysis and biosynthetic processes in chondrocytes, eventually causing cell death. To observe the effects of MIA and poly(lactic-co-glycolic acid) (PLGA)-based nanoparticles, histological analysis, immunohistochemistry, micro-CT, mechanical paw withdrawal thresholds, quantitative PCR, and measurement of oxygen consumption rate and extracellular acidification rate were conducted.Results: p-p66shc was highly expressed in cartilage from OA patients and rats with MIA-induced OA. MIA caused mitochondrial dysfunction and reactive oxygen species (ROS) production, and the inhibition of p66shc phosphorylation attenuated MIA-induced ROS production in human chondrocytes. Inhibition of p66shc by PLGA-based nanoparticles-delivered siRNA ameliorated pain behavior, cartilage damage, and inflammatory cytokine production in the knee joints of MIA-induced OA rats.Conclusion: p66shc is involved in cartilage degeneration in OA. By delivering p66shc-siRNA-loaded nanoparticles into the knee joints with OA, mitochondrial dysfunction-induced cartilage damage can be significantly decreased. Thus, p66shc siRNA PLGA nanoparticles may be a promising option for the treatment of OA.Keywords: osteoarthritis, monosodium iodoacetate, p66shc, ROS, mitochondrial dysfunction, PLGA-based nanoparticles

Min-Hee Yi,1 Juhee Shin,2,3 Nara Shin,2,3 Yuhua Yin,2,4 Sun Yeul Lee,4 Cuk-Seong Kim,3,5 Sang Ryong Kim,6 Enji Zhang,7 Dong Woon Kim2,31Department of Neurology, Mayo Clinic, Rochester, MN 55905, USA; 2Department of Anatomy, Brain Research Institute, Chungnam National University School of Medicine, Daejeon 301-747, Republic of Korea; 3Department of Medical Science, Chungnam National University School of Medicine, Daejeon 301-747, Republic of Korea; 4Department of Anesthesiology and Pain Medicine, Chungnam National University Hospital, Daejeon 301-747, South Korea; 5Department of Physiology, Chungnam National University School of Medicine, Daejeon 301-747, Republic of Korea; 6School of Life Sciences, BK21 Plus KNU Creative BioResearch Group, Institute of Life Science & Biotechnology, Brain Science and Engineering Institute, Kyungpook National University, Daegu 41566, Republic of Korea; 7Department of Anesthesia Medicine, Yanbian University Hospital, Yanbian 133000, People’s Republic of ChinaBackground: Mitophagy is the selective engulfment of mitochondria by autophagosomes and the subsequent mitochondrial catabolism by lysosomes. Evidence has suggested an important role for mitochondrial dynamics and mitophagic flux in the development of many different neurodegenerative diseases.Objectives: The potential role of the mechanism underlying mitochondrial dynamics and mitophagic flux as it may relate to neuropathic pain is not well understood. This is a disease that largely remains an area of mechanistic uncertainty. PINK1 is a PTEN-induced mitochondrial kinase that can be selectively activated under mitochondrial stress conditions and lead to the induction of mitophagy.Materials and methods: A neuropathic pain rat model was established via spinal nerve ligation (SNL) and nociception was assayed via the von Frey filament method. Increased expression of PINK1 and the mechanism of mitophagy was detected in GABAergic interneurons of dorsal horn neurons of mice that underwent L5 SNL in comparison to control mice counterparts (n=8, P

Francis O Obiweluozor,1,2,* Gladys A Emechebe,3,* Arjun Prasad Tiwari,3 Ju Yeon Kim,1 Chan Hee Park,1,3 Cheol Sang Kim1,3 1Division of Mechanical Design Engineering, Chonbuk National University, Jeonju City, Republic of Korea; 2Department of Chemical Engineering, Enugu State University of Science and Technology, Enugu State, Nigeria; 3Department of Bionanosystem Engineering Graduate School, Chonbuk National University, Jeonju City, Republic of Korea *These authors contributed equally to this work Background: The objective of this study was to evaluate the efficacy of a combination of Photothermal therapy (PTT) and chemotherapy in a single nano-fiber platform containing lethal polydopamine nano-pheres (PD NPs) for annihilation of CT 26 cancer cells.Method: Polydioxanone (PDO) nano-fiber containing PD and bortezomib (BTZ) was fabricated via electrospinning method. The content of BTZ and PD after optimization was 7% and 2.5% respectively with respect to PDO weight. PD NPs have absorption band in near-infrared (NIR) with resultant rapid heating capable of inducing cancer cell death. The samples was divided into three groups – PDO, PDO+PD, and PDO+PD-BTZ for analysis.Results: In combined treatment, PDO nano-fiber alone could not inhibit cancer cell growth as it neither contain PD or BTZ. However, PDO+PD fiber showed a cell viability of approximately 20% after 72 hr of treatment indicating minimal killing via hyperthermia. In the case of PDO composite fiber containing BTZ, the effect of NIR irradiation reduced the viability of cancer cells down to around 5% after 72 h showing the efficiency of combination therapy on cancer cells elimination. However, due to higher photothermal conversion that may negatively affect normal cells above 46°C, we have employed 1 s “OFF” and 2 s “ON” after initial 9 s continuous irradiation to maintain the temperature between 42 and 46°C over 3 mins of treatment using 2 W/cm2; 808 nm laser which resulted to similar cell death.Conclusion: In this study, combination of PTT and chemotherapy treatment on CT 26 colon cancer cells within 3 min resulted in effective cell death in contrast to single treatment of either PTT and chemotherapy alone. Our results suggest that this nano-fiber device with efficient heating and remote control drug delivery system can be useful and convenient in the future clinical application for localized cancer therapy. Keywords: electrospinning, polydopamine nanospheres, chemotherapy, photothermal therapy, electrospun nano-fiber, Bortezomib, local treatment, combination cancer therapy

Benedict J Kang,1,2,* Minhong Jeun,1,2,* Gun Hyuk Jang,1,2 Sang Hoon Song,3 In Gab Jeong,3 Choung-Soo Kim,3 Peter C Searson,4 Kwan Hyi Lee1,2 1KIST Biomedical Research Institute, 2Department of Biomedical Engineering, Korea University of Science and Technology (UST), 3Department of Urology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea; 4Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, MD, USA *These authors contributed equally to this work Abstract: Prostate cancer is one of the leading causes of cancer-related deaths among the Caucasian adult males in Europe and the USA. Currently available diagnostic strategies for patients with prostate cancer are invasive and unpleasant and have poor accuracy. Many patients have been overly or underly treated resulting in a controversy regarding the reliability of current conventional diagnostic approaches. This review discusses the state-of-the-art research in the development of novel noninvasive prostate cancer diagnostics using nanotechnology coupled with suggested diagnostic strategies for their clinical implication.Keywords: bioassay, nanomaterial, nanodevice, PSA, non-PSA biomarker, bodily fluid

Cheol-Su Kim,1,* Hai-Duong Nguyen,1,* Rosa Mistica Ignacio,2 Jae-Hyun Kim,1 Hyeon-Cheol Cho,1 Eun Ho Maeng,3 Yu-Ri Kim,4 Meyoung-Kon Kim,4 Bae-Keun Park,5 Soo-Ki Kim1,5 1Department of Microbiology, Wonju College of Medicine, Yonsei University, Wonju-si, Gangwon-do, Republic of Korea; 2Department of Environmental Medical Biology, Wonju College of Medicine, Yonsei University, Wonju-si, Gangwon-do, Republic of Korea; 3Healthcare Laboratory, Medical Device Evaluation Team, Korea Testing and Research Institute, Gimpo-si, Gyeonggi-do, Republic of Korea; 4Department of Biochemistry and Molecular Biology, Medical School and College, Korea University, Seoul, Republic of Korea; 5Institute of Lifestyle Medicine, Wonju College of Medicine, Yonsei University, Wonju-si, Gangwon-do, Republic of Korea *These authors contributed equally to this work Abstract: While zinc oxide (ZnO) nanoparticles (NPs) have been recognized to have promising applications in biomedicine, their immunotoxicity has been inconsistent and even contradictory. To address this issue, we investigated whether ZnO NPs with different size (20 or 100 nm) and electrostatic charge (positive or negative) would cause immunotoxicity in vitro and in vivo, and explored their underlying molecular mechanism. Using Raw 264.7 cell line, we examined the immunotoxicity mechanism of ZnO NPs as cell viability. We found that in a cell viability assay, ZnO NPs with different size and charge could induce differential cytotoxicity to Raw 264.7 cells. Specifically, the positively charged ZnO NPs exerted higher cytotoxicity than the negatively charged ones. Next, to gauge systemic immunotoxicity, we assessed immune responses of C57BL/6 mice after oral administration of 750 mg/kg/day dose of ZnO NPs for 2 weeks. In parallel, ZnO NPs did not alter the cell-mediated immune response in mice but suppressed innate immunity such as natural killer cell activity. The CD4+/CD8+ ratio, a marker for matured T-cells was slightly reduced, which implies the alteration of immune status induced by ZnO NPs. Accordingly, nitric oxide production from splenocyte culture supernatant in ZnO NP-fed mice was lower than control. Consistently, serum levels of pro/anti-inflammatory (interleukin [IL]-1Β, tumor necrosis factor-α, and IL-10) and T helper-1 cytokines (interferon-γ and IL-12p70) in ZnO NP-fed mice were significantly suppressed. Collectively, our results indicate that different sized and charged ZnO NPs would cause in vitro and in vivo immunotoxicity, of which nature is an immunosuppression. Keywords: immunosuppression, cytokine, ZnO, immune response, cytotoxicity, innate immunity

Yu-Ri Kim,1,* Seung-Young Lee,3,* Eun Jeong Lee,1 Sung Ha Park,4 Nak-won Seong,3 Heung-Sik Seo,3 Sung-Sup Shin,3 Seon-Ju Kim,3 Eun-Ho Meang,3 Myeong-Kyu Park,3 Min-Seok Kim,3 Cheol-Su Kim,5 Soo-Ki Kim,5 Sang Wook Son,2 Young Rok Seo,6 Boo Hyon Kang,7 Beom Seok Han,8 Seong Soo A An,9 Beom-Jun Lee,10 Meyoung-Kon Kim1 1Department of Biochemistry and Molecular Biology, 2Department of Dermatology, Korea University Medical School and College, 3General Toxicology Team, Korea Testing and Research Institute, Seoul, Republic of Korea; 4Department of Biochemistry, University of Bath, Bath, UK; 5Department of Microbiology, Wonju College of Medicine, Yonsei University, Gangwon, 6Department of Life Science, Institute of Environmental Medicine for Green Chemistry, Dongguk University, Seoul, 7Nonclinical Research Institute, Chemon Inc, Gyeonggi, 8Toxicological Research Center, Hoseo University, Chungnam, 9Department of Bionanotechnology, Gachon University, Gyeonggi, 10College of Veterinary Medicine, Chungbuk National University, Chungbuk, Republic of Korea *These authors contributed equally to this work Abstract: This study was undertaken to investigate the potential toxicity and establish the no observed adverse effect level (NOAEL) and target organ(s) of negatively charged colloidal silica particles of different sizes, ie, SiO2EN,20(-) (20 nm) or SiO2EN,100(-) (100 nm), administered by gavage in Sprague-Dawley rats. After verification of the physicochemical properties of the SiO2 particles to be tested, a preliminary dose range-finding study and 90-day repeated dose study were conducted according to the Organisation for Economic Cooperation and Development test guideline. Based on the results of the 14-day dose range-finding study, a high dose was determined to be 2,000 mg/kg, and middle and low doses were set at 1,000 and 500 mg/kg, respectively. In the 90-day toxicity study, there were no animal deaths in relation to administration of SiO2 particles of either size. In addition, no treatment-related clinical changes or histopathological findings were observed in any of the experimental groups. Moreover, no difference in toxic effects from chronic exposure to SiO2EN,20(-) (20 nm) or SiO2EN,100(-) (100 nm) was observed. The results of this study indicate that the NOAEL for SiO2EN,20(-) and SiO2EN,100(-) would most likely be 2,000 mg/kg, and no target organ was identified in rats of either sex. Keywords: silica nanoparticles, particle size, 90-day oral dose toxicity, no observed adverse effect level

Yu-Ri Kim,1,* Jong-Il Park,2,* Eun Jeong Lee,1 Sung Ha Park,3 Nak-won Seong,2 Jun-Ho Kim,2 Geon-Yong Kim,2 Eun-Ho Meang,2 Jeong-Sup Hong,2 Su-Hyon Kim,2 Sang-Bum Koh,2 Min-Seok Kim,2 Cheol-Su Kim,4 Soo-Ki Kim,4 Sang Wook Son,5 Young Rok Seo,6 Boo Hyon Kang,7 Beom Seok Han,8 Seong Soo A An,9 Hyo-In Yun,9 Meyoung-Kon Kim1 1Department of Biochemistry and Molecular Biology, Korea University Medical School and College, Seoul, Korea; 2General Toxicology Team, Korea Testing and Research Institute, Seoul, Korea; 3Department of Biochemistry, University of Bath, Bath, UK; 4Department of Microbiology, Wonju College of Medicine, Yonsei University, Wonju-si, Gangwon, Korea; 5Department of Life Science, Institute of Environmental Medicine for Green Chemistry, Dongguk University, Seoul, Korea; 6Nonclinical Research Institute, Chemon Inc., Yongin, Gyeonggi, Korea; 7Toxicological Research Center, Hoseo University, Ansan, Chungnam, Korea; 8Department of Bionanotechnology, Gachon University, Seongnam, Gyeonggi, Korea; 9College of Veterinary Medicine, Chungnam National University, Daejon, Korea *These authors contributed equally to this work Abstract: Nanoparticles (NPs) are used commercially in health and fitness fields, but information about the toxicity and mechanisms underlying the toxic effects of NPs is still very limited. The aim of this study is to investigate the toxic effect(s) of 100 nm negatively (ZnOAE100[-]) or positively (ZnOAE100[+]) charged zinc oxide (ZnO) NPs administered by gavage in Sprague Dawley rats, to establish a no observed adverse effect level, and to identify target organ(s). After verification of the primary particle size, morphology, hydrodynamic size, and zeta potential of each test article, we performed a 90-day study according to Organisation for Economic Co-operation and Development test guideline 408. For the 90-day study, the high dose was set at 500 mg/kg and the middle and low doses were set at 125 mg/kg and 31.25 mg/kg, respectively. Both ZnO NPs had significant changes in hematological and blood biochemical analysis, which could correlate with anemia-related parameters, in the 500 mg/kg groups of both sexes. Histopathological examination showed significant adverse effects (by both test articles) in the stomach, pancreas, eye, and prostate gland tissues, but the particle charge did not affect the tendency or the degree of the lesions. We speculate that this inflammatory damage might result from continuous irritation caused by both test articles. Therefore, the target organs for both ZnOAE100(-) and ZnOAE100(+) are considered to be the stomach, pancreas, eye, and prostate gland. Also, the no observed adverse effect level for both test articles was identified as 31.25 mg/kg for both sexes, because the adverse effects were observed at all doses greater than 125 mg/kg. Keywords: zinc oxide nanoparticles, surface charge, 90-day oral dose toxicity, no observed adverse effect level

Jae-Hyun Kim,1,* Cheol-Su Kim,1,* Rosa Mistica Coles Ignacio,2,* Dong-Heui Kim,2 Ma Easter Joy Sajo,2 Eun Ho Maeng,3 Xu-Feng Qi,4 Seong-Eun Park,5 Yu-Ri Kim,7 Meyoung-Kon Kim,7 Kyu-Jae Lee,2 Soo-Ki Kim1,5,6 1Department of Microbiology, 2Department of Environmental Medical Biology, Wonju College of Medicine, Yonsei University, Wonju-si, Gangwon-do, Republic of Korea; 3Healthcare Laboratory, Medical Device Evaluation, Korea Testing and Research Institute, Wonju-si, Gangwon-do, Republic of Korea; 4Key Laboratory for Regenerative Medicine of Ministry of Education and Department of Developmental and Regenerative Biology, School of Life Science and Technology, Ji Nan University, Guangzhou, People’s Republic of China; 5Institute of Lifestyle Medicine, Wonju College of Medicine, Yonsei University, Wonju-si, Gangwon-do, Republic of Korea; 6Institute of Biomaterials, Yonsei University, Wonju Campus, Wonju-si, Gangwon-do, Republic of Korea; 7Department of Biochemistry and Molecular Biology, Medical School and College, Korea University, Seoul, Republic of Korea *These authors contributed equally to this work Abstract: Silicon dioxide (SiO2) nanoparticles (NPs) have been widely used in the biomedical field, such as in drug delivery and gene therapy. However, little is known about the biological effects and potential hazards of SiO2. Herein, the colloidal SiO2 NPs with two different sizes (20 nm and 100 nm) and different charges (L-arginine modified: SiO2EN20[R], SiO2EN100[R]; and negative: SiO2EN20[-], SiO2EN100[-]) were orally administered (750 mg/kg/day) in female C57BL/6 mice for 14 days. Assessments of immunotoxicity include hematology profiling, reactive oxygen species generation and their antioxidant effect, stimulation assays for B- and T-lymphocytes, the activity of natural killer (NK) cells, and cytokine profiling. In vitro toxicity was also investigated in the RAW 264.7 cell line. When the cellularity of mouse spleen was evaluated, there was an overall decrease in the proliferation of B- and T-cells for all the groups fed with SiO2 NPs. Specifically, the SiO2EN20(-) NPs showed the most pronounced reduction. In addition, the nitric oxide production and NK cell activity in SiO2 NP-fed mice were significantly suppressed. Moreover, there was a decrease in the serum concentration of inflammatory cytokines such as interleukin (IL)-1Β, IL-12 (p70), IL-6, tumor necrosis factor-α, and interferon-γ. To elucidate the cytotoxicity mechanism of SiO2 in vivo, an in vitro study using the RAW 264.7 cell line was performed. Both the size and charge of SiO2 using murine macrophage RAW 264.7 cells decreased cell viability dose-dependently. Collectively, our data indicate that different sized and charged SiO2 NPs would cause differential immunotoxicity. Interestingly, the small-sized and negatively charged SiO2 NPs showed the most potent in vivo immunotoxicity by way of suppressing the proliferation of lymphocytes, depressing the killing activity of NK cells, and decreasing proinflammatory cytokine production, thus leading to immunosuppression. Keywords: silicon dioxide, nanoparticle, immunotoxicity, oxidative stress, cytokines, immunosuppression

We report a simultaneous dual-band wavelength-swept laser based on the active mode locking method. By applying a single modulation signal, synchronized sweeping of two lasing-wavelengths is demonstrated without the use of a mechanical wavelength-selecting filter. Two free spectral ranges are independently controlled with a dual path-length configuration of a laser cavity. The static and dynamic performances of a dual-band wavelength-swept active mode locking fiber laser are characterized in both the time and wavelength regions. Two lasing wavelengths were swept simultaneously from 1263.0 to 1333.3 nm for the 1310 nm band and from 1493 to 1563.3 nm for the 1550 nm band. The application of a dual-band wavelength-swept fiber laser was also demonstrated with a dual-band optical coherence tomography imaging system. © 1989-2012 IEEE.

We developed an optical frequency domain imaging (OFDI) system based on an integrated thermo-optic swept laser to achieve three-dimensional surface imaging. The wavelength was swept by applying a heating signal to a thermo-optic polymeric waveguide. The sub-micrometer surface profile was converted from the three-dimensional phase information of the OFDI system on various samples used as resolution targets with a step height of 120 nm. © 2014 IOP Publishing Ltd.

This paper shows experimentally dual wavelength swept at multi band (O,C-Band) property with active mode locking (AML) method. Unlike conventional wavelength swept laser, AML wavelength swept laser does not require any wavelength selecting filter in the cavity. The cavity has two free spectral ranges (FSRs) depend on dual path configuration. This wavelength swept laser can be useful for wide-band fiber-optic application such as Optical Coherence Tomography and Fiber Bragg Grating sensor system. © 2012 SPIE.

This paper shows experimentally dual wavelength swept at multi band (O, C-Band) property with active mode locking (AML) method. Unlike conventional wavelength swept laser, AML wavelength swept laser does not require any wavelength selecting filter in the cavity. The cavity has two free spectral ranges (FSRs) depend on dual path configuration. This wavelength swept laser can be useful for wi de-band fiber-optic application. © 2012 IEEE.

Optical coherence tomography (OCT) is a non-invasive and promising imaging modality with high resolution that is an order of magnitude higher than current diagnostic techniques. However, its use in detecting early-stage cancer is limited due to insufficient contrast level in biological tissue, which can be enhanced by harnessing contrast agents [e.g., gold nanoparticles (Au NPs)]. Enhanced penetration by creating micropassages and distribution by ultrasonic force (multimodal topical delivery) was proven to overcome two major barriers (stratum corneum and epithelial barriers) in topically administering Au NPs using an in vivo oral dysplasia hamster model (overall 150% enhanced OCT contrast). Expanded progress on a highly efficient and versatile Au NP-releasing polymer microneedle platform showed a promising next generation multi-modal delivery of Au NPs. © 2010 Copyright SPIE - The International Society for Optical Engineering.

Novel multi-wavelength switching filters based on cascaded long-period fiber grating (LPG) and polarization-maintaining fiber (PMF) in a Sagnac loop configuration are proposed and experimentally demonstrated. While the multi-channel spectrum of PMF Sagnac loop filter is controlled by the polarization state in the loop, the polarization-independence of the LPG filter is used to drop one channel. The polarization-independence of the cascaded LPG filter is also used for the fixed periodic loss spectrum to drop multiple channels in the loop. Although the polarization state of the optical wave filter is switched by the electro-optic modulator in the loop, the device is independent of the polarization state of the input light due to the bi-directional polarization compensation of the Sagnac loop interferometer. This device can be used to achieve all-channel gating and odd/even-channel switching with fine channel selectivity and high speed response.

We describe a novel scheme for complete suppression of polarization-dependent loss/gain (PDL, PDG) for transmission-type optical devices (LPG, SOA) via a l/2-shifted all-fiber Sagnac loop interferometer. The results are explained theoretically and demonstrated experimentally. © 2004 Optical Society of America.