Nanoarchitectonics of photothermal materials to enhance the sensitivity of lateral flow assays

• Elangovan Sarathkumar,
• Rajasekharan S. Anjana and
• Ramapurath S. Jayasree

Beilstein J. Nanotechnol. 2023, 14, 988–1003, doi:10.3762/bjnano.14.82

• nanosheets [92]. The photothermal properties of two-dimensional black phosphorous nanosheets was first utilized by Ren et al. in LFAs for the sensitive detection of norfloxacin in tap water. The nanoscale complex of magnetic upconversion particles and black phosphorus has a characteristic brown colour that

Cyclodextrins as eminent constituents in nanoarchitectonics for drug delivery systems

• Makoto Komiyama

Beilstein J. Nanotechnol. 2023, 14, 218–232, doi:10.3762/bjnano.14.21

• very stiff. Upon photoirradiation, however, the crosslinkings for the gel formation are broken almost completely, releasing the encapsulated drugs (e.g., DOX as anticancer drug). 2.3 Upconversion nanoparticles to release drugs by near-infrared light As an external stimulus for DDSs, near-infrared (NIR

• the use of upconversion nanoparticles to convert NIR to shorter-wavelength light for photoreactions. These nanoparticles usually contain rare-earth metal ions, which have long-living excited states. Thus, they achieve sequential energy absorption and convert two or more low-energy (NIR) photons into

• UV or visible light [54]. In a pioneering work [55], α- and β-CyDs were bound to the surface of upconversion nanoparticles and either azobenzene or arylazopyrazole was added to form inclusion complexes. NIR irradiation (980 nm) was converted to shorter-wavelength light, which isomerized azobenzene or

Recent advances in green carbon dots (2015–2022): synthesis, metal ion sensing, and biological applications

• Aisha Kanwal,
• Naheed Bibi,
• Sajjad Hyder,
• Arif Muhammad,
• Hao Ren,
• Jiangtao Liu and
• Zhongli Lei

Beilstein J. Nanotechnol. 2022, 13, 1068–1107, doi:10.3762/bjnano.13.93

Engineered titania nanomaterials in advanced clinical applications

• Padmavati Sahare,
• Paulina Govea Alvarez,
• Juan Manual Sanchez Yanez,
• Gabriel Luna-Bárcenas,
• Samik Chakraborty,
• Sujay Paul and
• Miriam Estevez

Beilstein J. Nanotechnol. 2022, 13, 201–218, doi:10.3762/bjnano.13.15

• extended periods of time relative to conventional organic photosensitizers, and they are non-toxic and stable without light irradiation. Thus, TiO2 nps activated by NIR light would be an attractive photosensitizing agent for PDT. A team of researchers has synthesized upconversion nps (UCNs) with a thin and

Effect of different silica coatings on the toxicity of upconversion nanoparticles on RAW 264.7 macrophage cells

• Cynthia Kembuan,
• Helena Oliveira and
• Christina Graf

Beilstein J. Nanotechnol. 2021, 12, 35–48, doi:10.3762/bjnano.12.3

• of Applied Sciences, Fachbereich Chemie- und Biotechnologie, Stephanstr. 7, D-64295 Darmstadt, Germany 10.3762/bjnano.12.3 Abstract Upconversion nanoparticles (UCNPs), consisting of NaYF4 doped with 18% Yb and 2% Er, were coated with microporous silica shells with thickness values of 7 ± 2 and 21

• : cytotoxicity; ion release; RAW 264.7 macrophage cell line; silica coating; upconversion nanoparticles; Introduction Upconversion nanoparticles (UCNPs) convert excitation radiation with long wavelengths to a short-wavelength emission. Since biological molecules do not have an upconversion mechanism, imaging

• macrophages and other immune cells, which eliminate foreign substances from the organism. Moreover, they have already been applied in studies involving uncoated NaGdF4 [42] and silica particles [43][44][45][46]. Upconversion cores consisting of NaYF4 doped with 18% Yb and 2% Er were synthesized. Microporous

Hexagonal boron nitride: a review of the emerging material platform for single-photon sources and the spin–photon interface

• Stefania Castelletto,
• Faraz A. Inam,
• Shin-ichiro Sato and
• Alberto Boretti

Beilstein J. Nanotechnol. 2020, 11, 740–769, doi:10.3762/bjnano.11.61

Coating of upconversion nanoparticles with silica nanoshells of 5–250 nm thickness

• Cynthia Kembuan,
• Maysoon Saleh,
• Bastian Rühle,
• Ute Resch-Genger and
• Christina Graf

Beilstein J. Nanotechnol. 2019, 10, 2410–2421, doi:10.3762/bjnano.10.231

• + upconversion nanoparticles (UCNP) is presented. The concept enables the precise adjustment of shell thicknesses for the preparation of thick-shelled nanoparticles for applications in plasmonics and sensing. First, an initial 5–11 nm thick shell is grown onto the UCNPs in a reverse microemulsion. This is

• -core particles are obtained. This strategy can be easily transferred to other nanomaterials for the design of plasmonic nanoconstructs and sensor systems. Keywords: reverse microemulsion; silica coating; stepwise growth; thick shells; upconversion nanoparticles; Introduction Lanthanide-based

• nanocrystals have gained importance as inorganic optical reporters in recent years [1][2][3]. The doping of inorganic host NaYF4 matrices with different optically active lanthanide ions can result in so-called upconversion nanoparticles (UCNP) which can absorb photons of lower energy (e.g., near-infrared (NIR

Janus-micromotor-based on–off luminescence sensor for active TNT detection

• Ye Yuan,
• Changyong Gao,
• Daolin Wang,
• Chang Zhou,
• Baohua Zhu and
• Qiang He

Beilstein J. Nanotechnol. 2019, 10, 1324–1331, doi:10.3762/bjnano.10.131

• Janus UCNP capsule motor is reduced, simplifying the visual detection of TNT. To assess the TNT detection capacity of the motors, they were dispersed in 5% H2O2 with and without TNT at pH 12. It was found that the upconversion luminescence of the Janus UCNP capsule motor exhibits no obvious change in

• movement in 5% H2O2 without TNT (Figure 3b and Video Supporting Information File 5). The time lapse image in Figure 3c (captured from the video in Supporting Information File 6) demonstrates that the upconversion luminescence of the Janus UCNP capsule motor decreased gradually with via self-propelled

• movement in 5% H2O2 with 0.5 mg mL−1 of TNT, indicating that the green upconversion luminescence (543 nm) of the UCNPs was quenched by the presence of TNT. The TNT sensing capability of these Janus UCNPs capsule motors was further evaluated by measuring the luminescence intensity. Figure 3d illustrates the

Time-resolved universal temperature measurements using NaYF₄:Er³⁺,Yb³⁺ upconverting nanoparticles in an electrospray jet

• Kristina Shrestha,
• Arwa A. Alaulamie,
• Ali Rafiei Miandashti and
• Hugh H. Richardson

Beilstein J. Nanotechnol. 2018, 9, 2916–2924, doi:10.3762/bjnano.9.270

• thickness of ca. 80 nm. (A) Upconversion emission spectra of UCNPs at different temperatures. A temperature-dependent green emission is measured for a temperature range of 306–493 K. (B) A plot of ln(H/S) vs 1/T for calibration of UCNPs. The H- (514–534 nm) and S- (536–548 nm) band area selected for the

Near-infrared light harvesting of upconverting NaYF₄:Yb³⁺/Er³⁺-based amorphous silicon solar cells investigated by an optical filter

• Daiming Liu,
• Qingkang Wang and
• Qing Wang

Beilstein J. Nanotechnol. 2018, 9, 2788–2793, doi:10.3762/bjnano.9.260

• light seriously restricts the photoelectric conversion efficiency of hydrogenated amorphous silicon (a-Si:H) thin film solar cells. Spectral upconversion is of great significance in reducing the wastage. Herein, the upconverting compound NaYF4:Yb3+/Er3+ was synthesized via a hydrothermal method. SEM and

• rods were incorporated in a polymethylmethacrylate (PMMA) layer on the rear side of a-Si:H solar cell. Under AM1.5 solar irradiation, a facile optical filter was used to scrutinize the effect of upconversion on the cell performance. Compared with a bare cell, the NaYF4:Yb3+/Er3+-based a-Si:H cell

• energy loss can be substantially reduced through spectral upconversion (UC) [6]. Spectral UC describes nonlinear anti-Stokes optical processes that can convert two (or more) NIR photons to a visible photon. In terms of its application in solar cells, UC is expected to convert the sub-bandgap NIR light to

Sugarcane juice derived carbon dot–graphitic carbon nitride composites for bisphenol A degradation under sunlight irradiation

• Lan Ching Sim,
• Jing Lin Wong,
• Chen Hong Hak,
• Jun Yan Tai,
• Kah Hon Leong and
• Pichiah Saravanan

Beilstein J. Nanotechnol. 2018, 9, 353–363, doi:10.3762/bjnano.9.35

• diffuse reflectance spectra (UV–vis DRS) results. Although the CDs did not display upconversion photoluminescence (UCPL) properties, the π-conjugated CDs served as a photosensitizer (like organic dyes) to sensitize g-C3N4 and injected electrons to the conduction band (CB) of g-C3N4, resulting in the

• graphitic carbon [1]. CDs possess upconversion photoluminescence (UCPL) properties [2] and are able to harvest long wavelength light in the visible and near infrared (NIR) region [3][4], rendering them promising candidates as photosensitizers in photocatalysis. Nevertheless, the reported preparation method

• consistent with previous reports [61]. A recent study by Wen and co-workers suggested that most of the CDs and graphene quantum dots (GQDs) do not have detectable upconversion fluorescence. The frequently cited UCPL properties could originate from the normal fluorescence excited by the leaking component from

Synthesis and functionalization of NaGdF₄:Yb,Er@NaGdF₄ core–shell nanoparticles for possible application as multimodal contrast agents

• Dovile Baziulyte-Paulaviciene,
• Vitalijus Karabanovas,
• Marius Stasys,
• Greta Jarockyte,
• Vilius Poderys,
• Simas Sakirzanovas and
• Ricardas Rotomskis

Beilstein J. Nanotechnol. 2017, 8, 1815–1824, doi:10.3762/bjnano.8.183

• contrast probe for in vivo bioimaging. Keywords: cancer theranostics; core–shell structure; luminescence; multimodal; nanoparticles; upconverting nanoparticles; upconversion; Introduction Lanthanide-doped multimodal upconverting nanoparticles (UCNPs), which can convert near-infrared (NIR) radiation into

• biologically active molecules, UCNPs could be multifunctional in both therapy and diagnostics (theranostics) [9]. However, biomedical applications require ultrasmall multifunctional nanoparticles to be hydrophilic, biocompatible and have intense upconversion emission and efficient paramagnetic properties

• . Hexagonal phase sodium gadolinium fluoride β-NaGdF4 is an ideal matrix for the creation optical/magnetic dual-modal bioprobes, but upconversion luminescence (UCL) efficiency of this host material is still low and needs to be improved. A major method to enhance the UCL intensity is to use a core–shell

Surface improvement of organic photoresists using a near-field-dependent etching method

• Felix J. Brandenburg,
• Tomohiro Okamoto,
• Hiroshi Saito,
• Benjamin Leuschel,
• Olivier Soppera and
• Takashi Yatsui

Beilstein J. Nanotechnol. 2017, 8, 784–788, doi:10.3762/bjnano.8.81

• are believed to be primarily present in the protrusions on the surface. Thus, O2 dissociation, and hence etching, occurs primarily at locations with a high protrusion density. Previous research suggests that near-field-based energy upconversion can also occur through multiphoton absorption instead of

Fabrication and properties of luminescence polymer composites with erbium/ytterbium oxides and gold nanoparticles

• Julia A. Burunkova,
• Ihor Yu. Denisiuk,
• Dmitri I. Zhuk,
• Lajos Daroczi,
• Attila Csik,
• István Csarnovics and
• Sándor Kokenyesi

Beilstein J. Nanotechnol. 2016, 7, 630–636, doi:10.3762/bjnano.7.55

• limitation to the concentration of RE ions is connected with a small oscillator strength of the Er3+ intra-4f transition at 1.54 μm (4I13/2→4I15/2)). Loss processes can easily dominate the de-excitation of the 4I13/2 level. Cooperative upconversion, which can dominate the de-excitation of the Er3+ 4I13/2

• + ions [5]. In Er-doped dielectrics, the Er concentration needs to be kept low to avoid concentration quenching and cooperative upconversion. The possible solution can be to increase the excitation efficiency at lower ion concentrations, also in presence of Yb ions. In some works [6][7][8] the increase

• magnitude. The excitation, luminescence and upconversion effects in the near-IR spectral region, usually investigated and described in literature, were not especially targeted here, although IR luminescence signals were detected in polymer nanocomposites (see below in Figure 7). Investigations of polymer

Silica-coated upconversion lanthanide nanoparticles: The effect of crystal design on morphology, structure and optical properties

• Uliana Kostiv,
• Miroslav Šlouf,
• Hana Macková,
• Alexander Zhigunov,
• Hana Engstová,
• Katarína Smolková,
• Petr Ježek and
• Daniel Horák

Beilstein J. Nanotechnol. 2015, 6, 2290–2299, doi:10.3762/bjnano.6.235

• :Yb3+/Er3+ nanoparticles at temperatures above 300 °C was confirmed by both ED and XRD. Upconversion luminescence under excitation at 980 nm was observed in the luminescence spectra of OM–NaYF4:Yb3+/Er3+ nanoparticles. Finally, the OM–NaYF4:Yb3+/Er3+ nanoparticles were coated with a silica shell to

• enable further functionalization and increase biocompatibility and stability in aqueous media, preventing particle aggregation. Keywords: lanthanide; nanoparticles; oleylamine; silica; upconversion; Introduction Due to their unique physicochemical properties, nanometer-scale materials are finding

• widespread applications as drug delivery systems in the diagnosis and treatment of various diseases [1][2]. Recently, upconversion nanoparticles have shown promise as optical materials [3] and a number of reviews [4][5][6] have described their applications in drug and gene delivery [7], cell labeling and

Overview about the localization of nanoparticles in tissue and cellular context by different imaging techniques

• Anja Ostrowski,
• Daniel Nordmeyer,
• Alexander Boreham,
• Cornelia Holzhausen,
• Lars Mundhenk,
• Christina Graf,
• Martina C. Meinke,
• Annika Vogt,
• Sabrina Hadam,
• Jürgen Lademann,
• Eckart Rühl,
• Ulrike Alexiev and
• Achim D. Gruber

Beilstein J. Nanotechnol. 2015, 6, 263–280, doi:10.3762/bjnano.6.25

• undergo photobleaching, photoactivation is a remarkable property of QD enhancing their quantum yield over time [90]. Another group of highly photostable NP are lanthanide-doped upconversion NP (UCNP). Upconversion is an optical process in which the sequential absorption of two or more photons leads to the

Influence of surface-modified maghemite nanoparticles on in vitro survival of human stem cells

• Michal Babič,
• Daniel Horák,
• Lyubov L. Lukash,
• Tetiana A. Ruban,
• Yurii N. Kolomiets,
• Svitlana P. Shpylova and
• Oksana A. Grypych

Beilstein J. Nanotechnol. 2014, 5, 1732–1737, doi:10.3762/bjnano.5.183

• for the above mentioned purposes [9]. Monosized iron oxide nanoparticles, sometimes called ultra-small superparamagnetic iron oxide nanoparticles, play the dominant role. Quantum dots, gold and, recently, also upconversion nanoparticles are used less frequently. The main advantages of iron oxides

Synthesis of hydrophobic photoluminescent carbon nanodots by using L-tyrosine and citric acid through a thermal oxidation route

• Venkatesh Gude

Beilstein J. Nanotechnol. 2014, 5, 1513–1522, doi:10.3762/bjnano.5.164

• air. These CNDs (less than 4 nm in size) exhibited a characteristic excitation wavelength dependent emission and upconversion emission properties and are insoluble in water, but soluble in organic solvents. FTIR and 1H NMR analyses showed a selective participation of L-tyrosine molecule during the

• : composite materials; fluorescence quenching; hydrophobic; luminescence; upconversion; Introduction The synthesis of fluorescent functional materials raised significant interest in order to understand biological processes such as DNA sequencing, detection of DNA-hybridization, protein sensing, single

• excitation wavelength dependent multicolor emission [2], upconversion photoluminescence (UCPL) [3], resistance to photobleaching, chemical and photochemical stability, low toxicity [4][5], and bio-compatibility. These associated properties of CNDs are exploited mostly in bio-imaging [6][7][8][9][10], bio

Nanostructure sensitization of transition metal oxides for visible-light photocatalysis

• Hongjun Chen and
• Lianzhou Wang

Beilstein J. Nanotechnol. 2014, 5, 696–710, doi:10.3762/bjnano.5.82

• photocatalytic mechanism for TiO2/carbon nanodots is schematically shown in Figure 9. When TiO2/carbon nanodots are illuminated by visible light, the carbon nanodots can absorb visible light (λ > 520 nm) and emit UV light (325 < λ < 425 nm) due to the PL upconversion of carbon nanodots. The UV light emitted by

• due to the photosensitization of carbon nanodots. By virtue of PL upconversion properties, carbon nanodots can also be used as photosensitizer to harness near-infrared light to further enhance the photocatalytic activity of some visible-light active semiconductors. Kang et al. recently reported that

• ) and then emit shorter wavelength light (300 to 530 nm) for the excitation of m-BiVO4 to further generate electron–hole pairs for photocatalytic degradation. Due to the special upconversion property of carbon nanodots, the carbon nanodots–m-BiVO4 nanospheres can be used as photocatalysts under the

Room temperature excitation spectroscopy of single quantum dots

• Christian Blum,
• Frank Schleifenbaum,
• Martijn Stopel,
• Sébastien Peter,
• Marcus Sackrow,
• Vinod Subramaniam and
• Alfred J. Meixner

Beilstein J. Nanotechnol. 2011, 2, 516–524, doi:10.3762/bjnano.2.56

• such as Förster resonance energy transfer (FRET) pairs, fluorescent proteins and upconversion particles. Experimental We realized an instrument capable of single molecule excitation spectroscopy by combining a high power supercontinuum white light source (Fianium SC-400pp) with a grating spectrometer