β-Ga2O3:Cr(3+) nanoparticle: A new platform with near infrared photoluminescence for drug targeting delivery and bio-imaging simultaneously

Nanomedicine: New Frontiers in Fighting Microbial Infections

Microbes have dominated life on Earth for the past two billion years, despite facing a variety of obstacles. In the 20th century, antibiotics and immunizations brought about these changes. Since then, microorganisms have acquired resistance, and various infectious diseases have been able to avoid being treated with traditionally developed vaccines. Antibiotic resistance and pathogenicity have surpassed antibiotic discovery in terms of importance over the course of the past few decades. These shifts have resulted in tremendous economic and health repercussions across the board for all socioeconomic levels; thus, we require ground-breaking innovations to effectively manage microbial infections and to provide long-term solutions. The pharmaceutical and biotechnology sectors have been radically altered as a result of nanomedicine, and this trend is now spreading to the antibacterial research community. Here, we examine the role that nanomedicine plays in the prevention of microbial infections, including topics such as diagnosis, antimicrobial therapy, pharmaceutical administration, and immunizations, as well as the opportunities and challenges that lie ahead.

Wide Dynamic Range Thermometer Based on Luminescent Optical Cavities in Ga2 O3 :Cr Nanowires

Remote temperature sensing at the micro- and nanoscale is key in fields such as photonics, electronics, energy, or biomedicine, with optical properties being one of the most used transducing mechanisms for such sensors. Ga₂ O₃ presents very high chemical and thermal stability, as well as high radiation resistance, becoming of great interest to be used under extreme conditions, for example, electrical and/or optical high-power devices and harsh environments. In this work, a luminescent and interferometric thermometer is proposed based on Fabry-Perot (FP) optical microcavities built on Cr-doped Ga₂ O₃ nanowires. It combines the optical features of the Cr³⁺ -related luminescence, greatly sensitive to temperature, and spatial confinement of light, which results in strong FP resonances within the Cr³⁺ broad band. While the chromium-related R lines energy shifts are adequate for low-temperature sensing, FP resonances extend the sensing range to high temperatures with excellent sensitivity. This thermometry system achieves micron-range spatial resolution, temperature precision of around 1 K, and a wide operational range, demonstrating to work at least in the 150-550 K temperature range. Besides, the temperature-dependent anisotropic refractive index and thermo-optic coefficient of this oxide have been further characterized by comparison to experimental, analytical, and finite-difference time-domain simulation results.

Anisotropic luminescence and third-order electric susceptibility of Mg-doped gallium oxide under the half-bandgap edge

Strong anisotropy of photoluminescence of a (100)-cut β-Ga₂O₃ and a Mg-doped β-Ga₂O₃ single crystals was found in UV and visible spectral range, the bands of which were attributed to different types of transitions in the samples. Green photoluminescence in the Mg-doped sample was enhanced approximately twice. A remarkable enhancement of two-photon absorption and self-focusing in β-Ga₂O₃ after doping was revealed by 340-fs laser Z-scanning at 515 nm. The absolute value of complex third order susceptibility χ⁽³⁾ determined from the study increases by 19 times in [001] lattice direction. Saturable absorption and associated self-defocusing were found in the undoped crystal in the [010] direction, which was explained by the anisotropic excitation of F-centers on intrinsic oxygen defects. This effect falls out of resonance in the Mg-doped crystal. The χ⁽³⁾ values which are provided by a decrease of bandgap in Mg-doped β-Ga₂O₃ are χ⁽³⁾ [001] = 1.85·10^-12 esu and χ⁽³⁾ [010]=χ⁽³⁾yyyy = 0.92·10^-12 esu. Our result is only one order of magnitude lower than the best characteristic in green demonstrated by a Mg-doped GaN, which encourages subsequent development of Mg-doped β-Ga₂O₃ as an effective nonlinear optical material in this region.

One-step solvothermal synthesis and growth mechanism of well-crystallized β-Ga2O3 nanoparticles in isopropanol

Well-crystallized β-Ga2O3 nanoparticles were synthesized by solvothermal treatment of Ga(NO3)3 in isopropanol at 400 °C without performing the calcination process.

Nano-Based Drug Delivery or Targeting to Eradicate Bacteria for Infection Mitigation: A Review of Recent Advances

Pathogenic bacteria infection is a major public health problem due to the high morbidity and mortality rates, as well as the increased expenditure on patient management. Although there are several options for antimicrobial therapy, their efficacy is limited because of the occurrence of drug-resistant bacteria. Many conventional antibiotics have failed to show significant amelioration in overall survival of infectious patients. Nanomedicine for delivering antibiotics provides an opportunity to improve the efficiency of the antibacterial regimen. Nanosystems used for antibiotic delivery and targeting to infection sites render some benefits over conventional formulations, including increased solubility, enhanced stability, improved epithelium permeability and bioavailability, prolonged antibiotic half-life, tissue targeting, and minimal adverse effects. The nanocarriers' sophisticated material engineering tailors the controllable physicochemical properties of the nanoparticles for bacterial targeting through passive or active targeting. In this review, we highlight the recent progress on the development of antibacterial nanoparticles loaded with antibiotics. We systematically introduce the concepts and amelioration mechanisms of the nanomedical techniques for bacterial eradication. Passive targeting by modulating the nanoparticle structure and the physicochemical properties is an option for efficient drug delivery to the bacteria. In addition, active targeting, such as magnetic hyperthermia induced by iron oxide nanoparticles, is another efficient way to deliver the drugs to the targeted site. The nanoparticles are also designed to respond to the change in environment pH or enzymes to trigger the release of the antibiotics. This article offers an overview of the benefits of antibacterial nanosystems for treating infectious diseases.

Effective targeted therapy for drug-resistant infection by ICAM-1 antibody-conjugated TPGS modified β-Ga2O3:Cr3+ nanoparticles

The prevalence of antibiotic resistance and lack of alternative drugs have posed an increasing threat to public health. Here, we prepared β-Ga₂O₃:Cr³⁺ nanoparticles modified with ICAM1-antibody-conjugated TPGS (I-TPGS/Ga₂O₃) as a novel antibiotic carrier for the treatment of drug-resistant infections.

Methods: I-TPGS/Ga₂O₃ were firstly characterized by measuring particle size, morphology, crystal structure, drug loading capacity, and in vitro drug release behaviors. The in vitro antibacterial activities of I-TPGS/Ga₂O₃/TIG were evaluated using standard and drug-resistant bacteria. The internalization of I-TPGS/Ga₂O₃ was observed by fluorescence confocal imaging, and the expression levels of the efflux pump genes of TRKP were analyzed by real-time RT-PCR. In vitro cellular uptake and in vivo biodistribution study were performed to investigate the targeting specificity of I-TPGS/Ga₂O₃ using HUEVC and acute pneumonia mice, respectively. The in vivo anti-infective efficacy and biosafety of I-TPGS/Ga₂O₃/TIG were finally evaluated using acute pneumonia mice.

Results: It was found that TPGS could down-regulate the over-expression of the efflux pump genes, thus decreasing the efflux pump activity of bacteria. I-TPGS/Ga₂O₃ with small particle size and uniform distribution facilitated their internalization in bacteria, and the TPGS modification resulted in a significant reduction in the efflux of loaded antibiotics. These properties rendered the encapsulated tigecycline to exert a stronger antibacterial activity both in vitro and in vivo. Additionally, targeted delivery of I-TPGS/Ga₂O₃ mediated by ICAM1 antibodies contributed to a safe and effective therapy.

Conclusion: It is of great value to apply I-TPGS/Ga₂O₃ as a novel and effective antibiotic delivery system for the treatment of drug-resistant infections.

Tocopherol polyethylene glycol succinate-modified hollow silver nanoparticles for combating bacteria-resistance

TPGS capped AgNPs could cross the bacterial cell wall and inhibit the activity of efflux pumps, eventually antagonize drug-resistance in the acute peritonitis model mice effectively.

Calpain activation and disturbance of autophagy are induced in cortical neurons in vitro by exposure to HA/β-Ga2O3:Cr3+ nanoparticles

The toxicity of engineered nanoparticles remains a concern. The knowledge of biohazards associated with particular nanoparticles is crucial to make this cutting-edge technology more beneficial and safe. Here, we evaluated the toxicity of Ga₂O₃ nanoparticles (NPs), which are frequently used to enhance the performance of metal catalysts in a variety of catalytic reactions. The potential inflammatory signaling associated with the toxicity of HA/β-Ga₂O₃:Cr³⁺ NPs in primary cortical neurons was examined. We observed a dose-dependent decrease in cell viability and an increase in apoptosis in neurons following various concentrations (0, 1, 5, 25, 50, 100 µg/ml) of HA/β-Ga₂O₃:Cr³⁺ NPs treatment. Consistently, constitutively active forms of calcineurin (48 kDa) were significantly elevated in cultured primary cortical neurons, which was consistent with calpain activation indicated by the breakdown products of spectrin. Moreover, HA/β-Ga₂O₃:Cr³⁺ NPs result in the elevation of LC3-II formation, SQSTM/p62, and Cathepsin B, whereas phosphorylation of CaMKII (Thr286) and Synapsin I (Ser603) were downregulated in the same context. Taken together, these results demonstrate for the first time that calpain activation and a disturbance of autophagy signaling are evoked by exposure to HA/β-Ga₂O₃:Cr³⁺ NPs, which may contribute to neuronal injury in vitro.

Controlling the shape of wedge-like α-GaOOH particles formed by a hydrolysis process using sodium acetate as a growth modifier

Sodium acetate preferentially suppresses the growth along thec-axis during the hydrolysis formation of α-GaOOH particles.

Gallium containing composites as a tunable material to understand neuronal behavior under variable stiffness and radiation conditions

We report a composite biomaterial containing nanostructured GaOOH and Matrigel™ that can be modulated with respect to its stiffness and radiosensitization properties. A variety of concentrations of GaOOH were added to the composite to alter the mechanical properties of the material as well as to tune the radiosensitizing properties to the composite. PC-12 cells were used to study the combined effects of different stimuli on cell behavior. NGF was given to the cells to record their morphology as well as viability. An increase in the substrate stiffness caused an increase in neurite outgrowth but a decrease in cell viability. In addition, increasing the radiation dose decreased neurite outgrowth but increased cell viability when radiosensitizing particles were present. A subtractive effect between radiosensitizing and mechanical stimuli was observed when PC-12 cells were grown on the GaOOH containing composite.

Investigation on cation distribution and luminescence in spinel phase γ-Ga3−δO4 : Sm nanostructures using X-ray absorption spectroscopy

In this study, spectroscopic investigations are employed to quantify the Ga distribution over the tetrahedral/octahedral sites and to assimilate the luminescence properties in the barely reported γ-Ga_2.67O₄ : Sm nanoparticles.

Interfaces with Tunable Mechanical and Radiosensitizing Properties

We report the fabrication of a composite containing nanostructured GaOOH and Matrigel with tunable radiosensitizing and stiffness properties. Composite characterization was done with microscopy and rheology. The utility of the interface was tested in vitro using fibroblasts. Cell viability and reactive oxygen species assays quantified the effects of radiation dosages and GaOOH concentrations. Fibroblasts' viability decreased with increasing concentration of GaOOH and composite stiffness. During ionizing radiation experiments the presence of the scintillating GaOOH triggered a different cellular response. Reactive oxygen species data demonstrated that one can reduce the amount of radiation needed to modulate the behavior of cells on interfaces with different stiffness containing a radiosensitizing material.

Active targeting co-delivery system based on pH-sensitive methoxy-poly(ethylene glycol)2K-poly(ε-caprolactone)4K-poly(glutamic acid)1K for enhanced cancer therapy

In this paper, we successfully synthesized folate-modified pH-sensitive copolymer methoxy-poly(ethylene glycol)2K-poly(ε-caprolactone)4K-poly(glutamic acid)1K (mPEG2K-PCL4K-PGA1K-FA), which could form the polymeric assembly in an aqueous solution, for co-delivering hydrophilic drugs doxorubicin hydrochloride (DOX) and verapamil hydrochloride (VER) (FA-poly(DOX+VER)). Since VER was an effective P-glycoprotein inhibitor, the combination of DOX and VER could reverse the multidrug resistance efficiently and enhance the therapeutic effect. Therefore, the inhibition ratios of MCF-7/ADR resistant cancer cell treated by FA-poly (DOX+VER) were almost more than 30% higher than those of FA-polyDOX after 48h and 72h. Furthermore, the conjugation of FA could lead the co-delivery systems actively targeting into the FA receptor over-expressing cancer cells in addition to the passive accumulation of the assembly in tumor tissues. Importantly, the prepared mPEG2K-PCL4K-PGA1K-FA assembly showed high pH-sensitive property, which made the drugs mostly released in tumor tissue (acid environment) than in physiological environment (neutral environment). In summary, the as-prepared co-delivery system FA-poly(DOX+VER) demonstrated a high efficiency in reversing the multidrug resistance and targeting FA receptor to improve the anticancer effect of DOX in MCF-7/ADR resistant cells.