scholarly journals Recent progress in the development of upconversion nanomaterials in bioimaging and disease treatment

2020 ◽  
Vol 18 (1) ◽  
Author(s):  
Gaofeng Liang ◽  
Haojie Wang ◽  
Hao Shi ◽  
Haitao Wang ◽  
Mengxi Zhu ◽  
...  
Keyword(s):  
Photodynamic Therapy ◽  
Biomedical Applications ◽  
Materials Science ◽  
Upconversion Luminescence ◽  
High Energy ◽  
Detection Sensitivity ◽  
Disease Treatment ◽  
Practical Applications ◽  
Advantages And Disadvantages ◽  
Luminescence Efficiency

Abstract Multifunctional lanthanide-based upconversion nanoparticles (UCNPs), which feature efficiently convert low-energy photons into high-energy photons, have attracted considerable attention in the domain of materials science and biomedical applications. Due to their unique photophysical properties, including light-emitting stability, excellent upconversion luminescence efficiency, low autofluorescence, and high detection sensitivity, and high penetration depth in samples, UCNPs have been widely applied in biomedical applications, such as biosensing, imaging and theranostics. In this review, we briefly introduced the major components of UCNPs and the luminescence mechanism. Then, we compared several common design synthesis strategies and presented their advantages and disadvantages. Several examples of the functionalization of UCNPs were given. Next, we detailed their biological applications in bioimaging and disease treatment, particularly drug delivery and photodynamic therapy, including antibacterial photodynamic therapy. Finally, the future practical applications in materials science and biomedical fields, as well as the remaining challenges to UCNPs application, were described. This review provides useful practical information and insights for the research on and application of UCNPs in the field of cancer.

scholarly journals Антистоксова люминесценция нанокристаллов Gd-=SUB=-2-=/SUB=-O-=SUB=-3-=/SUB=-, легированных ионами Er-=SUP=-3+-=/SUP=- и Yb-=SUP=-3+-=/SUP=-

2018 ◽  
Vol 44 (14) ◽  
pp. 42
Author(s):  
В.А. Пустоваров ◽  
Е.С. Трофимова ◽  
Ю.А. Кузнецова ◽  
А.Ф. Зацепин
Keyword(s):  
Vapor Deposition ◽  
Upconversion Luminescence ◽  
Average Particle Size ◽  
Chemical Vapor ◽  
High Energy ◽  
Structural Defects ◽  
Average Particle ◽  
Transfer Processes ◽  
Luminescence Efficiency ◽  
Anion Vacancies

AbstractThe upconversion luminescence (UCL) of nanocrystalline gadolinium oxide (Gd_2O_3) doped with Er^3+ and Yb^3+ ions has been studied in the temperature range of 90–400 K. The nanocrystals were synthesized by chemical vapor deposition and possessed a cubic crystalline structure with an average particle size within 48–57 nm. It is established that the USL intensity in the red (^4 F _9/2 → ^4 I _15/2 transition in Er3+ ion) and green (^4 S _3/2 → ^4 I _15/2 transition) spectral regions depends on the sample temperature and concentration of dopant ions, as well as on the additional structural defects (anion vacancies) created in the crystal lattice by the introduction of Zn^2+ ions or irradiation with high-energy (10 MeV) electrons. The luminescence efficiency and spectrum of the upconversion phosphor are determined by energy transfer processes.

scholarly journals Choroidal Neovascular Membrane (EYE) Treatment using Optical Fibre and LASER

2019 ◽  
Vol 9 (2) ◽  
pp. 191-194
Keyword(s):  
Photodynamic Therapy ◽  
Laser Beam ◽  
Laser Treatment ◽  
Choroidal Neovascularization ◽  
High Energy ◽  
Angioid Streaks ◽  
Choroidal Neovascular Membrane ◽  
Disease Treatment ◽  
Field Of Vision ◽  
The Individual

At the point when the eye experiences choroidal neovascularization, scar, or both, at the hour of treatment, the pace of repeat was 65% versus 33% if the concerned eye had no choroidal neovascularization, scar, or both. Normally a visual sharpness of four lines is lost when individual eyes had choroidal neovascularization, scar, or both, versus one line when the individual eye had no choroidal neovascularization or mark. Photocoagulation of choroidal neovascularization using LASER in patients experiencing angioid streaks can cause the ending of the choroidal neovascularization and adjustment of visual keenness. Treatment of choroidal neovascular membranes (CNVM) can differ depending on the concerned disease. Treatment consists of thermal laser treatment, anti-VEGF drugs, photodynamic therapy (PDT). Contingent upon the advancement of the illness, the individual may get at least one of these therapeutic treatment. Laser treatment is generally done as an outpatient strategy. It happens in the eye specialist's office or at the hospital. The LASER beam utilized in this treatment is a focused light having high energy.[5] It obliterates the abnormal blood veins, anticipating further spillage, dying, and development. After the laser treatment, vision may turn out to be more obscured than previously. Be that as it may, frequently it will balance out inside half a month. The treatment brings about a perpetual scar, making a lasting vulnerable side. This came about vulnerable sides, may be perceptible in the field of vision. Generally in the LASER treatment anomalous veins are demolished. In any case, patients regularly need re-treatment inside three to five years.

scholarly journals Recent Advances of Upconversion Nanomaterials in the Biological Field

Nanomaterials ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2474
Author(s):  
Cunjin Gao ◽  
Pengrui Zheng ◽  
Quanxiao Liu ◽  
Shuang Han ◽  
Dongli Li ◽  
...  
Keyword(s):  
Photodynamic Therapy ◽  
Near Infrared ◽  
Upconversion Luminescence ◽  
Chemical Properties ◽  
Biological Tissues ◽  
High Energy ◽  
Research Progress ◽  
High Signal ◽  
Bio Imaging ◽  
Anti Stokes

Rare Earth Upconversion nanoparticles (UCNPs) are a type of material that emits high-energy photons by absorbing two or more low-energy photons caused by the anti-stokes process. It can emit ultraviolet (UV) visible light or near-infrared (NIR) luminescence upon NIR light excitation. Due to its excellent physical and chemical properties, including exceptional optical stability, narrow emission band, enormous Anti-Stokes spectral shift, high light penetration in biological tissues, long luminescent lifetime, and a high signal-to-noise ratio, it shows a prodigious application potential for bio-imaging and photodynamic therapy. This paper will briefly introduce the physical mechanism of upconversion luminescence (UCL) and focus on their research progress and achievements in bio-imaging, bio-detection, and photodynamic therapy.

scholarly journals A Synergy Approach to Enhance Upconversion Luminescence Emission of Rare Earth Nanophosphors with Million-Fold Enhancement Factor

Crystals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1187
Author(s):  
Duc Tu Vu ◽  
Yi-Chang Tsai ◽  
Quoc Minh Le ◽  
Shiao-Wei Kuo ◽  
Ngoc Diep Lai ◽  
...  
Keyword(s):  
Cross Section ◽  
Absorption Cross Section ◽  
High Efficiency ◽  
Surface Defects ◽  
Organic Dyes ◽  
Upconversion Luminescence ◽  
High Energy ◽  
Absorption Cross ◽  
Excitation Light ◽  
Practical Applications

Lanthanide (Ln3+)–doped upconversion nanoparticles (UCNPs) offer an ennormous future for a broad range of biological applications over the conventional downconversion fluorescent probes such as organic dyes or quantum dots. Unfortunately, the efficiency of the anti−Stokes upconversion luminescence (UCL) process is typically much weaker than that of the Stokes downconversion emission. Albeit recent development in the synthesis of UCNPs, it is still a major challenge to produce a high−efficiency UCL, meeting the urgent need for practical applications of enhanced markers in biology. The poor quantum yield efficiency of UCL of UCNPs is mainly due to the fol-lowing reasons: (i) the low absorption coefficient of Ln3+ dopants, the specific Ln3+ used here being ytterbium (Yb3+), (ii) UCL quenching by high−energy oscillators due to surface defects, impurities, ligands, and solvent molecules, and (iii) the insufficient local excitation intensity in broad-field il-lumination to generate a highly efficient UCL. In order to tackle the problem of low absorption cross-section of Ln3+ ions, we first incorporate a new type of neodymium (Nd3+) sensitizer into UCNPs to promote their absorption cross-section at 793 nm. To minimize the UCL quenching induced by surface defects and surface ligands, the Nd3+-sensitized UCNPs are then coated with an inactive shell of NaYF4. Finally, the excitation light intensity in the vicinity of UCNPs can be greatly enhanced using a waveguide grating structure thanks to the guided mode resonance. Through the synergy of these three approaches, we show that the UCL intensity of UCNPs can be boosted by a million−fold compared with conventional Yb3+–doped UCNPs.

In situ TEM Studies of agglomeration of sub-nanometer Ru layers in Ru/C multilayers

1992 ◽  
Vol 50 (1) ◽  
pp. 256-257
Author(s):  
Tai D. Nguyen ◽  
Ronald Gronsky ◽  
Jeffrey B. Kortright
Keyword(s):  
Layered Structure ◽  
Driving Force ◽  
High Energy ◽  
Superior Performance ◽  
In Situ Tem ◽  
Rayleigh Instability ◽  
Practical Applications ◽  
Transmission Electron ◽  
Diffraction Patterns

Nanometer period Ru/C multilayers are one of the prime candidates for normal incident reflecting mirrors at wavelengths < 10 nm. Superior performance, which requires uniform layers and smooth interfaces, and high stability of the layered structure under thermal loadings are some of the demands in practical applications. Previous studies however show that the Ru layers in the 2 nm period Ru/C multilayer agglomerate upon moderate annealing, and the layered structure is no longer retained. This agglomeration and crystallization of the Ru layers upon annealing to form almost spherical crystallites is a result of the reduction of surface or interfacial energy from die amorphous high energy non-equilibrium state of the as-prepared sample dirough diffusive arrangements of the atoms. Proposed models for mechanism of thin film agglomeration include one analogous to Rayleigh instability, and grain boundary grooving in polycrystalline films. These models however are not necessarily appropriate to explain for the agglomeration in the sub-nanometer amorphous Ru layers in Ru/C multilayers. The Ru-C phase diagram shows a wide miscible gap, which indicates the preference of phase separation between these two materials and provides an additional driving force for agglomeration. In this paper, we study the evolution of the microstructures and layered structure via in-situ Transmission Electron Microscopy (TEM), and attempt to determine the order of occurence of agglomeration and crystallization in the Ru layers by observing the diffraction patterns.

Recent Patents on the Angular Contact Ball Bearing of High-Speed Motorized Spindle

2020 ◽  
Vol 13 ◽  
Author(s):  
Yudong Bao ◽  
Linkai Wu ◽  
Yanling Zhao ◽  
Chengyi Pan
Keyword(s):  
High Speed ◽  
Ball Bearing ◽  
Rapid Development ◽  
Ceramic Materials ◽  
Development Trend ◽  
Numerical Control ◽  
Angular Contact Ball Bearing ◽  
Practical Applications ◽  
High Speed Cutting ◽  
Advantages And Disadvantages

Background:: Angular contact ball bearings are the most popular bearing type used in the high speed spindle for machining centers, The performance of the bearing directly affects the machining efficiency of the machine tool, Obtaining a higher value is the direction of its research and development. Objective:: By analyzing the research achievements and patents of electric spindle angular contact bearings, summarizing the development trend provides a reference for the development of electric spindle bearings. Methods:: Through the analysis of the relevant technology of the electric spindle angular contact ball bearing, the advantages and disadvantages of the angular contact ball bearing are introduced, and the research results are combined with the patent analysis. Results:: With the rapid development of high-speed cutting and numerical control technology and the needs of practical applications, the spindle requires higher and higher speeds for bearings. In order to meet the requirements of use, it is necessary to improve the bearing performance by optimizing the structure size and improving the lubrication conditions. Meanwhile, reasonable processing and assembly methods will also have a beneficial effect on bearing performance. Conclusion:: With the continuous deepening of bearing technology research and the use of new structures and ceramic materials has made the bearing's limit speed repeatedly reach new highs. The future development trend of high-speed bearings for electric spindles is environmental protection, intelligence, high speed, high precision and long life.

scholarly journals How to Improve Physico-Chemical Properties of Silk Fibroin Materials for Biomedical Applications?—Blending and Cross-Linking of Silk Fibroin—A Review

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1510
Author(s):  
Sylwia Grabska-Zielińska ◽  
Alina Sionkowska
Keyword(s):  
Silk Fibroin ◽  
Biomedical Applications ◽  
Magnetic Particles ◽  
Chemical Properties ◽  
Ternary Mixtures ◽  
Cross Linking ◽  
Advantages And Disadvantages ◽  
Physico Chemical ◽  
Binary And Ternary Mixtures ◽  
To Receive

This review supplies a report on fresh advances in the field of silk fibroin (SF) biopolymer and its blends with biopolymers as new biomaterials. The review also includes a subsection about silk fibroin mixtures with synthetic polymers. Silk fibroin is commonly used to receive biomaterials. However, the materials based on pure polymer present low mechanical parameters, and high enzymatic degradation rate. These properties can be problematic for tissue engineering applications. An increased interest in two- and three-component mixtures and chemically cross-linked materials has been observed due to their improved physico-chemical properties. These materials can be attractive and desirable for both academic, and, industrial attention because they expose improvements in properties required in the biomedical field. The structure, forms, methods of preparation, and some physico-chemical properties of silk fibroin are discussed in this review. Detailed examples are also given from scientific reports and practical experiments. The most common biopolymers: collagen (Coll), chitosan (CTS), alginate (AL), and hyaluronic acid (HA) are discussed as components of silk fibroin-based mixtures. Examples of binary and ternary mixtures, composites with the addition of magnetic particles, hydroxyapatite or titanium dioxide are also included and given. Additionally, the advantages and disadvantages of chemical, physical, and enzymatic cross-linking were demonstrated.

scholarly journals Organic dots (O-dots) for theranostic applications: preparation and surface engineering

RSC Advances ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 2253-2291
Author(s):  
Amin Shiralizadeh Dezfuli ◽  
Elmira Kohan ◽  
Sepand Tehrani Fateh ◽  
Neda Alimirzaei ◽  
Hamidreza Arzaghi ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Photodynamic Therapy ◽  
Photothermal Therapy ◽  
Biomedical Applications ◽  
Surface Engineering ◽  
Graphene Quantum Dots ◽  
Carbon Quantum Dots ◽  
Cargo Delivery ◽  
Bio Imaging ◽  
Theranostic Applications

Organic dots is a term used to represent materials including graphene quantum dots and carbon quantum dots because they rely on the presence of other atoms (O, H, and N) for their photoluminescence or fluorescence properties. Cargo delivery, bio-imaging, photodynamic therapy and photothermal therapy are major biomedical applications of organic dots.

scholarly journals Diagnosis of Herpes Simplex Virus: Laboratory and Point-of-Care Techniques

2021 ◽  
Vol 13 (2) ◽  
pp. 518-539
Author(s):  
Peuli Nath ◽  
Md Alamgir Kabir ◽  
Somaiyeh Khoubafarin Doust ◽  
Aniruddha Ray
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Point Of Care ◽  
Diagnostic Techniques ◽  
Nucleic Acid Amplification ◽  
Physical Contact ◽  
Detection Sensitivity ◽  
Detection Techniques ◽  
Advantages And Disadvantages ◽  
Simplex Virus

Herpes is a widespread viral infection caused by the herpes simplex virus (HSV) that has no permanent cure to date. There are two subtypes, HSV-1 and HSV-2, that are known to cause a variety of symptoms, ranging from acute to chronic. HSV is highly contagious and can be transmitted via any type of physical contact. Additionally, viral shedding can also happen from asymptomatic infections. Thus, early and accurate detection of HSV is needed to prevent the transmission of this infection. Herpes can be diagnosed in two ways, by either detecting the presence of the virus in lesions or the antibodies in the blood. Different detection techniques are available based on both laboratory and point of care (POC) devices. Laboratory techniques include different biochemical assays, microscopy, and nucleic acid amplification. In contrast, POC techniques include microfluidics-based tests that enable on-spot testing. Here, we aim to review the different diagnostic techniques, both laboratory-based and POC, their limits of detection, sensitivity, and specificity, as well as their advantages and disadvantages.

scholarly journals Recent Advances in the Development of Exogenous dsRNA for the Induction of RNA Interference in Cancer Therapy

Molecules ◽  
2021 ◽  
Vol 26 (3) ◽  
pp. 701
Author(s):  
Tatiana S. Golubeva ◽  
Viktoria A. Cherenko ◽  
Konstantin E. Orishchenko
Keyword(s):  
Gene Expression ◽  
Rna Interference ◽  
Molecular Biology ◽  
Gene Silencing ◽  
Regulation Of Gene Expression ◽  
Research Area ◽  
Disease Treatment ◽  
Practical Applications ◽  
Agricultural Plants ◽  
Insect Reproduction

Selective regulation of gene expression by means of RNA interference has revolutionized molecular biology. This approach is not only used in fundamental studies on the roles of particular genes in the functioning of various organisms, but also possesses practical applications. A variety of methods are being developed based on gene silencing using dsRNA—for protecting agricultural plants from various pathogens, controlling insect reproduction, and therapeutic techniques related to the oncological disease treatment. One of the main problems in this research area is the successful delivery of exogenous dsRNA into cells, as this can be greatly affected by the localization or origin of tumor. This overview is dedicated to describing the latest advances in the development of various transport agents for the delivery of dsRNA fragments for gene silencing, with an emphasis on cancer treatment.

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