Herein, a dual-responsive insulin delivery device by integrating glucose- and HO-responsive polymeric vesicles (PVs) with transcutaneous microneedles (MNs) has been designed. This novel microneedle delivery device achieves a goal of fast response, excellent biocompatibility, and painless administration. The PVs are self-assembled from a triblock copolymer including poly(ethylene glycol), poly(phenylboronic acid) (glucose-sensitive block), and poly(phenylboronic acid pinacol ester) (HO-sensitive block). After loading with insulin and glucose oxidase (GO ), the drug-loaded PVs display a basal insulin release as well as a promoted insulin release in response to hyperglycemic states. The insulin release rate responds quickly to elevated glucose and can be further promoted by the incorporated GO , which will generate the HO at high glucose levels and further break the chemical links of phenylboronic acid pinacol ester group. Finally, the transdermal delivery of insulin to the diabetic rats ((insulin + GO )-loaded MNs) presents an effective hypoglycemic effect compared to that of subcutaneous injection or only insulin-loaded MNs, which indicates the as-prepared MNs insulin delivery system could be of great importance for the applications in the therapy of diabetes.

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The turning point of the refractive index (RI) sensitivity based on the multimode microfiber (MMMF) in-line Mach-Zehnder Interferometer (MZI) is firstly observed.By tracking the resonant wavelength shift of the MZI generated between HE11 and HE12 modes in the MMMF, the surrounding RI (SRI) could be detected. Theoretical analysis demonstrates that the RI sensitivity will be reached to ±∞ on either side of the turning point due that the group effective RI difference (G) approaches to zero. Significantly, the positive sensitivity exists in a much wide fiber diameter range while the negative sensitivity can be achieved in a narrow diameter range of only 0.3μm. Meanwhile, the experimental sensitivities and variation trend at different diameters exhibit high consistency with the theoretical results. High RI sensitivity of 10777.8nm/RIU at the fiber diameter of 4.6μm and the RI around 1.3334 is realized. The discovery of the sensitivity turning points has great significance on trace detection due to the possibility of ultra-high RI sensitivity. © 2015 Optical Society of America http://dx.doi.org/ XXXX /OL. XX. XXXX XX Fiber-based sensors have been widely investigated for the measurement of chemical and biomedical parameters due to their unique merits, such as compact size, electromagnetic interference immunity, potential low cost, and usage in harsh environment [1][2][3][4][5]. Especially, ultra-high sensitive refractive index (RI) fiber sensors are significant for biochemical trace detection. When the fiber is surface immobilized with functional materials, it can realize selective and accurate biochemical identification [6][7][8].Recently, the microfiber, with promising optical properties of large evanescent field, low transmission loss, high nonlinear effect, and tight optical confinement, has become attractive in photonics fields [9][10][11][12][13]. One kind of microfiber i.e. multimode microfiber (MMMF), also called non-adiabatic tapered fiber, is simply fabricated through tapering a conventional single mode fiber (SMF) into micrometer size. Different from the adiabatic tapered fiber, the MMMF has a much larger transition angle [19], resulting in the excitation of few guided modes inthe transition region. Then, an in-line Mach-Zehnder interference (MZI) is generated in only one standard microfiber due to the interference between the two dominant modes. MMMF has shown outstanding performance in refractive index (RI) sensing with high sensitivity of 10 3 ～10 4 nm/RIU [20][21][22] and temperature sensing with the sensitivity up to -3.88nm/ o C [22]. However, to the best of our knowledge, systematic investigation on the sensing performance of the MMMF based in-line Mach-Zehnder interferometer (MZI) especially the RI sensitivity characteristics has not been reported.In this letter, we establish the RI sensing modal and systematically analyze the sensitivity of the MMMF based in-line MZI. By comprehensively calculating the effective RI of the supporting modes, the mode field distribution, and the group effective RI diff...

A multimode microfiber (MMMF)-based dual Mach-Zehnder interferometer (MZI) is proposed and demonstrated for simultaneous measurement of refractive index (RI) and temperature. By inserting a section of MMMF supporting a few modes in the sensing arm of the MZI setup, an inline interference between the fundamental mode and the high-order mode of MMMF, as well as the interference between the high-order mode of MMMF and the reference arm, i.e., the dual MZI, is realized. Due to different interference mechanisms, the former interferometer achieves RI sensitivity of 2576.584  nm/RIU and temperature sensitivity of -0.193  nm/°C, while the latter one achieves RI sensitivity of 1001.864  nm/RIU and temperature sensitivity of 0.239  nm/°C, demonstrating the ability to attain highly accurate multiparameter measurements.

We report the study of lasing modes in broad-area, equilateral-triangular laser cavities. An alternative approach is proposed to study optical modes in equilateral triangular cavities in an analytical form. The modes were obtained by examining the simplest optical paths inside the cavity, which yields the final solution with the boundary conditions. The cavities can be fabricated from semiconductor heterostructures grown on ͑111͒oriented substrates, which can be easily cleaved into equilateral triangular shapes. Such a design takes advantage of total internal reflection at the cleaved facets of the cavity for circulating modes. Experimental results are obtained from cavities fabricated from a superlattice structure of In 0.13 Ga 0.87 As/GaAs grown on a ͑111͒ GaAs substrate.

A near-infrared (NIR)-responsive drug delivery system was established by grafting UCST polymers on the surfaces of hollow mesoporous silica nanoparticles (HMSNs) using the photothermal agent indocyanine green (ICG), which provided a new and promising strategy for drug delivery.

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We demonstrate efficient tuning of a monolithically integrated lithium niobate microdisk (LN) optical frequency microcomb. Utilizing the high optical quality (Q) factor (i.e., Q~7.1×10 6 ) of the microdisk, the microcomb spans over a spectral bandwidth of ~200 nm at a pump power as low as 20.4 mW. Combining the large eletrooptic coefficient of LN and optimum design of the geometry of microelectrodes, we demonstrate electro-optical tuning of the comb with a spectral range of 400 pm and a tuning efficiency of ~38 pm/100V.