WSe2/BN heterostructure as saturable absorber for a diode-pumped passively Q-switched 2†µm solid-state laser.

We have successfully achieved the synthesis of heterojunction consisting of WSe2 and BN, by using a liquid phase exfoliation method, and characterization of the prepared materials under the microstructure. The WSe2/BN heterojunction was used as a saturable absorber in the Tm:YAP laser for passively Q-switched operation, and a pulsed laser with an output wavelength around 2 µm range was successfully obtained. After comparing the effects of resonators composed of different cavity mirrors, it is concluded that when the curvature radius of the input mirror is 250 mm and the transmittance of the output coupler is 2.5%, the best output performance was obtained. The maximum average output power of 834 mW was achieved, with a pulsed repetition frequency of 43.51 kHz and a minimum pulse duration of 1.28 µs, corresponding to a peak power of 14.97 W and a maximum single pulse energy of 19.17 µJ.

Influence of polyethyleneglycol modification on phagocytic uptake of polymeric nanoparticles mediated by immunoglobulin G and complement activation.

The purpose of this study is to investigate the influence of polyethyleneglycol (PEG) modification on in vitro phagocytic uptake of polymeric nanoparticles (NPs) mediated by immunoglobulin G (IgG) and complement activation. A series of PEG-modified poly (D, L-lactide-co-glycolide) nanoparticles (PEG-PLGA-NPs) were incubated in pure serum protein or whole serum, and their capacity for adsorbing albumin and the serum total proteins was measured by a bicinchoninic acid (BCA) protein assay. The adsorption of serum total IgG and complement activation was investigated by enzyme-linked immunosorbent assay (ELISA). To measure in vitro uptake, various fluorescently labeled (Nile red) PEG-PLGA-NPs were opsonized by different pre-treated sera and subsequently incubated with phagocytes. The uptake of NPs by macrophages was then measured by fluorescence spectrometry. Longer chain length and appropriate content PEG reduced the adsorption of serum proteins and complement activation by NPs via both the classical and the alternative pathways. The phagocytosis of PEG-PLGA-NPs by murine peritoneal macrophages (MPMs) involved both serum-independent and serum-dependent phagocytosis. PEG modification was shown only to reduce serum-dependent phagocytosis, mainly by inhibiting IgG adsorption and complement activation on NP surfaces, and the effect of complement activation was greater than that of IgG. The results of this study provided new information that may assist in the design of more efficient nano drug carriers for medical applications.