Photoluminescence enhancement for blue-green emission in copper-alloyed lead-free cesium halide single crystals.

Recently, metal halides have received extensive attention because of the superior photophysical characteristics. Regardless of the superiority, the limited stability against heat and moisture and the toxicity problem of heavy lead metal are obstacles to the realization of wide range applications. In this case, it is necessary to develop eco-friendly alternatives, which could simultaneously maintain the excellent optoelectronic properties of lead materials. In this paper, the synthesis of lead-free one-dimensional Cs2AgBr3 and Cu(I)-alloyed Cs2AgBr3 single crystals (SCs) has been successfully realized. Experimental results demonstrated that the addition of applicable copper ions could greatly improve their luminescence intensity. A bright blue-green photoluminescence peaking at 510 nm was observed after incorporating Cu+ ions into Cs2AgBr3 SCs under UV irradiation. Theoretical calculation further proved that the incorporation of Cu+ could effectively modulate the materials' electronic band structure; the electronic states limited to the CuBr4 tetrahedron presented a strong localized property, which was beneficial to increase the photoluminescence efficiency. In addition, the SCs displayed favorable structure stability proofing moisture and oxygen under ambient conditions, proving that this material has good prospects for the development of optoelectronic fields.

Bright luminescence from nontoxic all-inorganic low-dimensional cesium halide.

Due to the superiority of low cost, easy manufacture, and tunable light emission owing to the diversity of compositions and dimensionalities, the metal halides have appeared as a promising class of semiconductors. Nevertheless, the toxicity problem along with inherent instability of Pb-based metal halides greatly limits their large-scale applications. Based on this situation, it is necessary to develop eco-friendly materials, which could simultaneously maintain the excellent optoelectronic properties of lead materials. In this Letter, the one-dimensional Cu + -alloyed Cs2AgI3 has been successfully synthesized. An intense blue emission located at 469 nm with a large Stokes shift was observed. Density functional theory calculation indicated that the Cu+ ions could effectively modulate the density of state population, which was the key factor drastically boosting the photoluminescence quantum yield (PLQY). This kind of highly efficient metal halide may overcome the bottlenecks of toxicity and poor efficiency issues of blue emission and will have a promising prospect in the optoelectronic fields.

Silver@Prussian Blue Core-Satellite Nanostructures as Multimetal Ions Switch for Potent Zero-Background SERS Bioimaging-Guided Chronic Wound Healing.

Metal-organic framework-based metal ion therapy has attracted increasing attention to promote the cascade wound-healing process. However, multimetal ion synergistic administration and accurately controlled ion release are still the challenges. Herein, an aptamer-functionalized silver@cupriferous Prussian blue (ACPA) is established as a metal-based theranostic nanoagent for a chronic nonhealing diabetic wound treatment. Prussian blue offers a programmable nanoplatform to formulate metal ion prescriptions, achieving cooperative wound healing. Silver, copper, and iron ions are released from ACPA controlled by the near-infrared-triggered mild hyperthermia and then synergistically participate in antipathogen, cell migration, and revascularization. ACPA also demonstrates a unique core-satellite nanostructure which enables it with improved surface-enhanced Raman scattering (SERS) capability as potent bacteria-targeted Raman-silent nanoprobe to monitor the residual bacteria during wound healing with nearly zero background. The theranostic feature of ACPA allows high-performance SERS imaging-guided chronic wound healing in infectious diabetic skin and keratitis.

Are graphene-Bi2Te3 van der Waals heterostructure-based saturable absorbers promising for solid-state Q-switched lasers?

This Letter compared the absorption characteristics of a homemade graphene-Bi2Te3 (G-B) van der Waals heterostructure to a Bi2Te3 topological insulator (TI) with a similar preparation method and number of layers. The results indicate that the G-B heterostructure can tremendously enhance the modulation depth and saturable intensity. In addition, a passively Q-switched laser at 1.06 µm with a G-B heterostructure as a saturable absorber (SA) was demonstrated for the first time, to the best of our knowledge. Compared to Bi2Te3 TI, the G-B heterostructure Q-switched laser had better laser performance, indicating that a G-B heterostructure is a promising SA candidate for a 1 µm laser.

Visible to near-infrared octave spanning supercontinuum generation in tantalum pentoxide (Ta2O5) air-cladding waveguide.

In this work, for the first time, to the best of our knowledge, an anomalous dispersion CMOS-compatible Ta2O5 waveguide was realized, and broadband on-chip supercontinuum generation (SCG) was accordingly demonstrated. When pumped at a center wavelength of 1056 nm with pulses of 100 fs duration and peak power of 396 W, a supercontinuum ranging from 585 nm to 1697 nm was generated, comprising a bandwidth of more than 1.5 octaves and leading to an efficient SCG source. The excellent performance for Ta2O5 to generate SCG benefits mainly from its high nonlinear refractive index, which enhances the efficiency of the nonlinear conversion process.

Fabrication and analysis of single-crystal KTiOPO4 films with thicknesses in the micrometer range.

Single-crystal potassium titanyl phosphate (KTiOPO4, KTP) films with thicknesses less than 5 µm are obtained by using helium (He) implantation combined with ion-beam-enhanced etching. A heavily damaged layer created by a 4×10(16) cm(-2) fluence of 2 MeV He implantation is removed by means of wet chemical etching in hydrofluoric acid (HF). Thus, free-standing films of KTP with thicknesses in the range of 3-5 µm are obtained. The etching rate can be adjusted over a wide range by choosing temperature and HF concentration, as well as annealing conditions. Sharp etching edges and the smooth surface of the film indicate that a high selective-etching rate is achieved in the damaged layer, and the remaining part of the crystal is undamaged. X-ray and Raman-scattering results prove that KTP films have good single-crystal properties.

The Effect of Particle Size on the Absorption of Cyclosporin A Nanosuspensions.

Background: Cyclosporin A (CsA) is a hydrophobic drug widely used as an immunosuppressant and anti-rejection drug in solid organ transplantation. On the market, there are two oral CsA formulations available containing polyoxyethylene castor oil, which can cause serious allergic reactions and nephrotoxicity. In order to eliminate polyoxyethylene castor oil, CsA was formulated into a nanosuspension. This study aimed to design an oral cyclosporin A nanosuspensions (CsA-NSs) and investigate the effect of particle size on absorption of CsA-NSs. Methods: CsA-NSs were prepared using a wet bead milling method. Particle size, morphology and crystallinity state of CsA-NSs were characterized. The in vitro dissolution, the intestinal absorption properties and pharmacokinetic study of CsA-NSs were investigated. Results: CsA-NSs with sizes of 280 nm, 522 nm and 2967 nm were prepared. The shape of CsA-NSs with smaller size was similar to that of spheres. The crystallinity of CsA in nanocrystals was reduced. The dissolution rate of CsA-NSs (280 nm) was greater than that of CsA-NSs (522 nm) and CsA-NSs (2967 nm). CsA-NSs (280 nm) showed higher absorption rate constants (Kα ) and effective permeability coefficients (Peff ) of different intestinal segments compared with that of CsA-NSs (522 nm) and CsA-NSs (2967 nm). AUC0-48h of 280 nm CsA-NSs was about 1.12-fold of that of 522 nm CsA-NSs, and about 1.51-fold of that of 2967 nm CsA-NSs. In particular, the particle size of CsA-NSs was nanoscale, and their bioavailability was bioequivalent with marked self-microemulsion (Sandimmun Neoral®). Conclusion: It is feasible to prepare CsA-NSs. The dissolution rate, gastrointestinal transport properties and the oral absorption of CsA-NSs were promoted by reducing size. Considering the cost, efficiency and energy consumption, there should be an optimal particle size range in industrial production.

Thermosensitive Hydrogels and Advances in Their Application in Disease Therapy.

Thermosensitive hydrogels, having unique sol-gel transition properties, have recently received special research attention. These hydrogels exhibit a phase transition near body temperature. This feature is the key to their applications in human medicine. In addition, hydrogels can quickly gel at the application site with simple temperature stimulation and without additional organic solvents, cross-linking agents, or external equipment, and the loaded drugs can be retained locally to improve the local drug concentration and avoid unexpected toxicity or side effects caused by systemic administration. All of these features have led to thermosensitive hydrogels being some of the most promising and practical drug delivery systems. In this paper, we review thermosensitive hydrogel materials with biomedical application potential, including natural and synthetic materials. We describe their structural characteristics and gelation mechanism and briefly summarize the mechanism of drug release from thermosensitive hydrogels. Our focus in this review was to summarize the application of thermosensitive hydrogels in disease treatment, including the postoperative recurrence of tumors, the delivery of vaccines, the prevention of postoperative adhesions, the treatment of nervous system diseases via nasal brain targeting, wound healing, and osteoarthritis treatment.

Intracranial In Situ Thermosensitive Hydrogel Delivery of Temozolomide Accomplished by PLGA-PEG-PLGA Triblock Copolymer Blending for GBM Treatment.

Glioblastoma (GBM) recurrence after surgical excision has grown to be a formidable obstacle to conquer. In this research, biodegradable thermosensitive triblock copolymer, poly(D, L-lactic acid-co-glycolic acid)-b-poly(ethylene glycol)-b-poly(D, L-lactic acid-co-glycolic acid (PLGA-PEG-PLGA) was utilized as the drug delivery system, loading with micronized temozolomide(micro-TMZ) to form an in situ drug-gel depot inside the resection cavity. The rheology studies revealed the viscoelastic profile of hydrogel under various conditions. To examine the molecular characteristics that affect gelation temperature, 1H-NMR, inverse gated decoupling 13C-NMR, and GPC were utilized. Cryo-SEM and XRD were intended to disclose the appearance of the hydrogel and the micro-TMZ existence state. We worked out how to blend polymers to modify the gelation point (Tgel) and fit the correlation between Tgel and other dependent variables using linear regression. To simulate hydrogel dissolution in cerebrospinal fluid, a membraneless dissolution approach was used. In vitro, micro-TMZ@PLGA-PEG-PLGA hydrogel exhibited Korsmeyer-Peppas and zero-order release kinetics in response to varying drug loading, and in vivo, it suppressed GBM recurrence at an astoundingly high rate. Micro-TMZ@PLGA-PEG-PLGA demonstrates a safer and more effective form of chemotherapy than intraperitoneal TMZ injection, resulting in a spectacular survival rate (40%, n = 10) that is much more than intraperitoneal TMZ injection (22%, n = 9). By proving the viability and efficacy of micro-TMZ@PLGA-PEG-PLGA hydrogel, our research established a novel chemotherapeutic strategy for treating GBM recurrence.

Review of nanosuspension formulation and process analysis in wet media milling using microhydrodynamic model and emerging characterization methods.

Wet media milling is a popular technology used to prepare nanosuspensions. However, the theories and methods to guide the research on the formulation and process affecting wet media milling remain limited. The research on wet media milling follows a "black box" approach to a certain extent. This review focuses on exploring the formulation and process parameters factors in wet media milling. The formulation factors include the concentration, hydrophilicity/hydrophobicity, and structure of the drug and stabilizer, whereas the milling process parameters include the milling speed, milling time, and material, size, and filling volume of milling beads. Contrary to other reviews, this review attempts to quantify and visualize these factors by combining a microhydrodynamic model with emerging characterization methods to provide a scientific basis for the selection of nanosuspension formulations and process parameters, as opposed to the conventional trial-and-error approach.

Paclitaxel-nanocrystals-loaded network thermosensitive hydrogel for localised postsurgical recurrent of breast cancer after surgical resection.

The recurrence of cancer after local surgery has been a difficult problem in the clinic for a long time. In recent years, local treatment via drug-loaded thermosensitive hydrogels have become a promising strategy to prevent cancer recurrence. Thus, a thermosensitive hydrogel based on poloxamer 407, poloxamer 188 and the bioadhesive excipient carbomer 974P was designed to locally release paclitaxel and prevent local tumour recurrence after direct smearing of the hydrogel at the site of injury in the surgical cavity. To improve the local drug concentration, paclitaxel was prepared into nanocrystals via a wet mill process. A series of studies were performed on this paclitaxel nanocrystal thermosensitive hydrogel (PTX-NCS-gel), including examination of its rheological properties and in vitro release and dissolution studies. Moreover, a postoperative tumour recurrence mouse model was established to evaluate the antitumour effects of this thermosensitive hydrogel. The results showed that PTX-NCS-gel had a clear, regular network structure with excellent temperature sensitivity and could be gelated within minutes at 33.1 °C. Additionally, the rheological property investigation indicated that the hydrogel has proper viscoelasticity and self-recovery ability. In vivo imaging showed that PTX-NCS-gel inhibited both local tumour recurrence and distant metastasis. Moreover, PTX-NCS-gel has the following advantages: it is more convenient to administer, avoids strong allergic responses, and has fewer side effects on the liver and spleen. This hydrogel has the potential to serve as a powerful auxiliary medication to prevent postoperative local tumour recurrence.

Dasatinib self-assembled nanoparticles decorated with hyaluronic acid for targeted treatment of tumors to overcome multidrug resistance.

Multidrug resistance (MDR) and lack of targeting specificity are the main reasons why traditional drug therapies fail and produce toxic side effects in cancer chemotherapy. In order to increase targeting specificity and maximize therapeutic efficacy, new intelligent drug delivery systems are needed. In this study, we prepared the hyaluronic acid (HA) conjugated dasatinib (DAS) and D-α-tocopherol acid polyethylene glycolsuccinate (TPGS) copolymer nanoparticles (THD-NPs). The water solubility of the hydrophobic drug DAS was improved by chemically linking with HA. HA can bind to the over-expressed CD44 protein of tumor cells to increase targeting specificity, TPGS can inhibit the activity of P-glycoprotein (P-gp), and increase the intracellular accumulation of drugs. The prepared drug-loaded nanoparticle has a particle size of 82.23 ± 1.07 nm with good in vitro stability. Our in vitro studies showed that THD-NPs can be released more rapidly in a weakly acidic environment (pH = 5.5) than in a normal physiological environment (pH = 7.4), which can realize the selective release of nanoparticles in tumor cells. Compared to free drugs, THD-NPs showed more efficient cellular uptake, effectively increased the cytotoxic effect of DAS on nasopharyngeal carcinoma HNE1 cells drug resistance HNE1/DDP cells and increased the accumulation of drugs in HNE1/DDP cells, which may be due to the inhibitory effect of TPGS on the efflux function of P-gp. In vivo experiments showed that THD-NPs can effectively inhibit tumor growth without obvious side effects. In conclusion, the targeted and pH-sensitive nanosystem, we designed has great potential to overcome drug resistance and increase therapeutic effects in cancer treatment.

A Combined Self-Assembled Drug Delivery for Effective Anti-Breast Cancer Therapy.

AIM: The metastasis of breast cancer is an important cause of tumor recurrence. This study highlights that tyrosine kinase inhibitors dasatinib (DAS) and rosiglitazone (ROZ) inhibit tumor growth and reduce the occurrence of tumor cell metastasis. Due to the poor water solubility, short half-time in the body of DAS and ROZ, which increases the difficulty of tumor treatment, as well as the demand for nano-drug delivery systems for organ-specific therapies. METHODS: Hyaluronic acid (HA) and DAS are bonded by a pH-sensitive ester bond to form an HA-DAS polymer. Then, ROZ was added as the core, D-A-tocopherol polydiethylene glycol isosuccinate (TPGS) and HA-DAS were used as carriers to form HA-DAS and TPGS mixed micelle system loaded with ROZ (THDR-NPs). The size and structure of THDR-NPs were characterized, the drug release, stability and biosafety of THDR-NPs were studied. In vitro, the cytotoxicity, targeting effect and tumor metastasis inhibition of THDR-NPs were evaluated in human breast cancer cell lines. In addition, the selective potency of designed THDR-NPs in depleting was further verified in vivo in the tumor-bearing nude mice model. RESULTS: The designed THDR-NPs have a particle size of less than 100 nm, good stability, biological safety and sustained release, and showed strong therapeutic effects on breast cancer models in vitro and in vivo. Moreover, it has been proved that THDR-NPs have the ability to inhibit tumor metastasis. CONCLUSION: DAS and ROZ were designed into micelles, the efficacy of THDR-NPs was higher than that of free drugs. These results indicate that nanoparticles have a good application prospect in the treatment of tumor metastasis.

Higher order mode supercontinuum generation in tantalum pentoxide (Ta2O5) channel waveguide.

We fabricated tantalum pentoxide (Ta2O5) channel waveguides and used them to experimentally demonstrate higher-order mode supercontinuum (SC) generation. The Ta2O5 waveguide has a high nonlinear refractive index which was in an order magnitude of 10-14 cm2/W and was designed to be anomalously dispersive at the pumping wavelength. To the best of our knowledge, this is the first time a higher-order mode femtosecond pump based broadband SC has been measured from a nonlinear waveguide using the phase-matching method. This enabled us to demonstrate a SC spectrum spanning from 842 to 1462 nm (at - 30 dB), which corresponds to 0.83 octaves, when using the TM10 waveguide mode. When using the TE10 mode, the SC bandwidth is slightly reduced for the same excitation peak power. In addition, we theoretically estimated and discussed the possibility of using the broadband higher-order modes emitted from the Ta2O5 waveguide for trapping nanoparticles. Hence, we believe that demonstrated Ta2O5 waveguide are a promising broadband light source for optical applications such as frequency metrology, Raman spectroscopy, molecular spectroscopy and optical coherence tomography.

Bacteria-induced aggregation of bioorthogonal gold nanoparticles for SERS imaging and enhanced photothermal ablation of Gram-positive bacteria.

The challenge in antimicrobial photothermal therapy (PTT) is to develop strategies for decreasing the damage to cells and increasing the antibacterial efficiency. Herein, we report a novel theranostic strategy based on bacteria-induced gold nanoparticle (GNP) aggregation, in which GNPs in situ aggregated on the bacterial surface via specific targeting of vancomycin and bioorthogonal cycloaddition. Plasmonic coupling between adjacent GNPs exhibited a strong "hot spot" effect, enabling effective surface enhanced Raman scattering (SERS) imaging of bacterial pathogens. More importantly, in situ aggregation of GNPs showed strong NIR adsorption and high photothermal conversion, allowing enhanced photokilling activity against Gram-positive bacteria. In the absence of bacterial strains, GNPs were dispersed and showed a very low photothermal effect, minimizing the side effects towards surrounding healthy tissues. Given the above advantages, the bioorthogonal theranostic strategy developed in this study may find potential applications in treating bacterial infection and even multidrug-resistant bacteria.

Effect of Ge Nanocrystals on 1.54 µm Photoluminescence Enhancement in Er2O3:ZnO and Ge Co-Sputtered Films.

Photoluminescence (PL) of Er and Ge co-doped ZnO films synthesized by radio frequency magnetron co-sputtering was investigated. X-ray diffraction (XRD) patterns showed that the annealing process at 400-800 °C led to the formation of nanocrystal (nc) Ge. Samples containing nc-Ge showed a strong visible PL with a peak at 582-593 nm, which was consistent with the calculated energy of the exciton of the ~5 nm-sized nc-Ge, according to the quantum confinement effect. The formation of nc-Ge could greatly enhance the 1.54 µm emission, and it is considered that the 1.54 µm PL enhancement may come from a joint effect of both the energy transfer from nc-Ge to Er3+ and the local environment change of Er3+.