Self-assembly and spectroscopic fingerprints of photoactive pyrenyl tectons on hBN/Cu(111)

• Domenik M. Zimmermann,
• Knud Seufert,
• Luka Ðorđević,
• Tobias Hoh,
• Sushobhan Joshi,
• Tomas Marangoni,
• Davide Bonifazi and
• Willi Auwärter

Beilstein J. Nanotechnol. 2020, 11, 1470–1483, doi:10.3762/bjnano.11.130

• characterizing a family of pyridin-4-ylethynyl-functionalized pyrene derivatives in different environments. UV–vis measurements in toluene solutions revealed absorption at wavelengths consistent with density functional theory (DFT) calculations, while emission experiments showed a high fluorescence quantum yield

• ][48][49][50][51][52][53][54]. With prominent fluorescence properties, pyrene is often considered the "fruitfly of photochemists", and several materials have been prepared for applications in optoelectronic devices and organic electronics [47]. On metal surfaces under ultrahigh vacuum (UHV

• , studies comparing orbital-resolved STM/STS data to optical gaps are scarce [86]. In addition to this effect, the adsorption and supramolecular organization on hBN could sensitively affect the optical transitions [14][16][21]. For example, the fluorescence peak energy of perylene derivatives was reduced

Antimicrobial metal-based nanoparticles: a review on their synthesis, types and antimicrobial action

• Matías Guerrero Correa,
• Fernanda B. Martínez,
• Cristian Patiño Vidal,
• Camilo Streitt,
• Juan Escrig and
• Carol Lopez de Dicastillo

Beilstein J. Nanotechnol. 2020, 11, 1450–1469, doi:10.3762/bjnano.11.129

• constituent can be determined after 24 h of incubation [149]. The cytofluorometry method is an advanced and important technique that allows for the accurate identification of a cell population with fluorescence tagging by using a flow cytometer and a photodetector [150]. In comparison to other techniques

Transient coating of γ-Fe₂O₃ nanoparticles with glutamate for its delivery to and removal from brain nerve terminals

• Konstantin Paliienko,
• Artem Pastukhov,
• Michal Babič,
• Daniel Horák,
• Olga Vasylchenko and
• Tatiana Borisova

Beilstein J. Nanotechnol. 2020, 11, 1381–1393, doi:10.3762/bjnano.11.122

• ratio (F), index of the membrane potential, was calculated as F = Ft/F0, where F0 and Ft were the fluorescence intensities of rhodamine 6G in the absence and presence of nerve terminals, respectively. F0 was calculated through extrapolation of the exponential decay function to t = 0. The fluorescence

• measurements were carried out using the potential-sensitive fluorescent dye rhodamine 6G, which binds to negatively charged membranes. The addition of synaptosomes to the dye-containing medium was accompanied by a partial decrease in fluorescence signal due to rhodamine 6G binding to the synaptosomal plasma

• membrane. First, the membrane potential index at the steady-state level was reached after a period of 3 min. As shown in Figure 4, the application of γ-Fe2O3 nanoparticles at a concentration of 1 µg/mL did not change the fluorescence signal of the dye. An increase in the nanoparticle concentration up to 50

Ultrasensitive detection of cadmium ions using a microcantilever-based piezoresistive sensor for groundwater

• Dinesh Rotake,
• Anand Darji and
• Nitin Kale

Beilstein J. Nanotechnol. 2020, 11, 1242–1253, doi:10.3762/bjnano.11.108

• been already identified. Sensors based on luminescence or fluorescence sensors have been used by many researchers to selectively detect HMIs [17][18][19][20][21][22]. However, this method also requires laboratory equipment for analysis and detection. Also, most of the reported fluorescent probes reply

• only on absorption and fluorescence change and need dynamic acquisition [23]. A magnetic field powered pressure sensor proposed by Khan et al. [24] is capable of measuring pressure in the range of kilopascals but the suitability for the very low pressure caused by HMIs needs to be examined. A reduced

• nanoparticles require the laboratory equipment such as fluorescence spectroscopy, which ultimately leads to a non-portable platform. Hence, our primary focus is the selective detection of the Cd(II) using the fabricated portable experimental platform. We used the following experimental procedure. A stock

Thermophoretic tweezers for single nanoparticle manipulation

• Jošt Stergar and
• Natan Osterman

Beilstein J. Nanotechnol. 2020, 11, 1126–1133, doi:10.3762/bjnano.11.97

• multiple heating spots by time-sharing (switching frequency 100 kHz) of the beam. Behind the AODs, the laser beam is directed by mirrors and an afocal system towards a custom-built fluorescence microscope. Finally, it is focused with a long working distance IR objective (Mitutoyo M Plan Apo NIR, 50×, NA

•  1b,c). Temperature measurements are performed using the temperature-dependent fluorescence of sulforhodamine B (Radiant dyes Chemie), which is calibrated in an independent measurement (accuracy ±2 K). Since the sapphire glass with a high thermal conductivity helps cooling the thin sample film, the

• implemented using a custom-built fluorescence microscope. By using an LED-optimized filter cube (Dapi/FITC/Cy3/Cy5 Quad LED HC Filter Set, AHF analysentechnik AG), Köhler illumination is utilized for fluorescence imaging using an LED as its light source. Light is collected from the sample plane by a 63

Applications of superparamagnetic iron oxide nanoparticles in drug and therapeutic delivery, and biotechnological advancements

• Maria Suciu,
• Corina M. Ionescu,
• Alexandra Ciorita,
• Septimiu C. Tripon,
• Dragos Nica,
• Hani Al-Salami and
• Lucian Barbu-Tudoran

Beilstein J. Nanotechnol. 2020, 11, 1092–1109, doi:10.3762/bjnano.11.94

• on the environment. Many nanoparticles showed great potential and proved their utility in biology and medicine. There are multiple types of nanoparticles routinely used in biology and related sciences for sensing, targeting or imaging, including quantum dots for fluorescence applications and electron

• been extensively examined regarding biocompatibility, targeted or intended cytotoxicity (ferroptosis), local hyperthermia treatments, photothermal or photodynamic therapy, and MRI. Also, there are increasingly more studies reporting on combinations with in vivo fluorescence imaging, sensing and

• for MRI and fluorescence imaging with good cytocompatibility. Park et al. [161] synthesized SPIONs coated with folate containing 64Cu for positronic emission tomography and MRI. Cai et al. [162] obtained 12 nm SPIONs coated with a near-infrared fluorescent dye for dual in vivo imagistics (MRI and

A few-layer graphene/chlorin e6 hybrid nanomaterial and its application in photodynamic therapy against Candida albicans

• Selene Acosta,
• Carlos Moreno-Aguilar,
• Dania Hernández-Sánchez,
• Beatriz Morales-Cruzado,
• Erick Sarmiento-Gomez,
• Carla Bittencourt,
• Luis Octavio Sánchez-Vargas and
• Mildred Quintana

Beilstein J. Nanotechnol. 2020, 11, 1054–1061, doi:10.3762/bjnano.11.90

• 3.5 mm at 1000 nm excitation [7]. Figure 3b shows the singlet oxygen production tests of FLG-Ce6 and pristine Ce6. The singlet oxygen production is indirectly observed through the fluorescence intensity of the singlet oxygen sensor green reagent (SOSG), which is a singlet oxygen reporter. Thus, FLG

• -Ce6 and pristine Ce6 samples were exposed to SOSG and photoactivated during 5, 10, and 15 min of visible light irradiation at 632 nm at an incident power of 150 mW. When analyzed using fluorescence spectroscopy, it was observed that ROS production is up to 5-fold higher in FLG-Ce6 than in pristine Ce6

• ROS that accumulate in its surroundings. Conclusion The FLG-Ce6 hybrid nanomaterial presented in this work was shown to enhance the capacity for the generation of ROS species compared with Ce6 alone, as corroborated by measuring the fluorescence intensity produced by the reporter SOSG. This hybrid

Key for crossing the BBB with nanoparticles: the rational design

• Sonia M. Lombardo,
• Marc Schneider,
• Akif E. Türeli and
• Nazende Günday Türeli

Beilstein J. Nanotechnol. 2020, 11, 866–883, doi:10.3762/bjnano.11.72

• -6 was an accurate probe for the nanoparticle detection. It was therefore possible to conclude that the fluorescence detected in the abluminal compartment during the transcytosis assay was due to the probe inside the nanoparticles, and not due to free coumarin-6. Hence, it seems that CBSA-conjugated

• fluorescence imaging [68]. Nanoparticles could be observed in the glioma bed and infiltrating margin, showing that nanoparticles functionalized with angiopep-2 could exhibit dual-targeting abilities. Firstly, angiopep-2 allowed the nanoparticles to cross the BBB through RMT by recognition of LRP1 on the BBB

• ]. Using in vivo fluorescence molecular tomography revealed that the SLNs could be observed in the brain after intravenous and intratracheal administration, showing their ability to cross the BBB. Furthermore, a superior retention of the nanoparticles in the brain was noticed after intratracheal

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

• ⟩. Making use of the above discussion, the second order correlation function for the fluorescence light of a 2-level system can be written as: Using the quantum regression theorem [70], we get: where with the evolution of written as for some operator As the expectation value gives the population of the

• function for the fluorescence light of a 2-level system is at τ = 0, g(2)(τ) = 0. Therefore, a non-resonantly driven 2-level system behaves as an SPS, emitting light in the SP state. The anti-bunching decay time τ0 for zero excitation power (i.e., k12 = 0) is τ0(P → 0) = 1/k12. Since k12 is the decay time

• of the excited state, τ0(P → 0) is the fluorescence lifetime of the 2-level emitter. A 3-level system comprises an intermediate meta-stable state together with the ground and the excited states. Figure 1c shows the representation of a 3-level system. The state |3⟩ is a metastable state, i.e

Silver-decorated gel-shell nanobeads: physicochemical characterization and evaluation of antibacterial properties

• Marta Bartel,
• Katarzyna Markowska,
• Marcin Strawski,
• Krystyna Wolska and
• Maciej Mazur

Beilstein J. Nanotechnol. 2020, 11, 620–630, doi:10.3762/bjnano.11.49

• . The analyses were conducted using the LIVE/DEAD BacLight bacterial viability kit and the samples were imaged with confocal fluorescence microscopy [50]. The test uses the properties of fluorescent dyes, namely, green SYTO 9 and red propidium iodide. The SYTO 9 stain labels the bacteria with intact

• membranes and those with damaged membranes. In contrast, propidium iodide penetrates only the bacteria with damaged membranes, thereby reducing the fluorescence of SYTO 9 when both dyes are present. The living cells appear green while the dead cells are red in the images of the biofilms. One can see that

• nanobeads, which likely stabilizes these structures. The hybrid particles reveal considerable antibacterial properties. This has been evaluated based on the determination of MIC and MBIC values and an estimation of bacterial viability through fluorescence staining. Experimental Chemicals All chemicals were

Soybean-derived blue photoluminescent carbon dots

• Shanshan Wang,
• Wei Sun,
• Dong-sheng Yang and
• Fuqian Yang

Beilstein J. Nanotechnol. 2020, 11, 606–619, doi:10.3762/bjnano.11.48

• varies with pH and temperature [18]. Wang et al. [18] studied the fluorescence of the CDs made from glucose with glutathione in a temperature range of 15 to 90 °C and observed the change of the color from dark blue to light blue and the quenching of the fluorescence at high temperatures. They attributed

• at various wavelengths. The Raman scattering of the annealed CDs has a relatively low yield. The Raman peaks can be only observed when the gain or slit bandwidth of the instrument is increased to compensate for the low fluorescence signal. In contrast to the annealed-CDs, the LA-CDs-10%, which are

• % under 393 nm excitation. Temporal evolution of the quantum yields for the HTC-CDs under 360 nm excitation and the LA-CDs-x% under 390 nm excitation. The fluorescence intensity was calculated by integrating over the wavelength range of 340–700 nm for the HTC-CDs and 370–760 nm for the LA-CDs-x

Examination of the relationship between viscoelastic properties and the invasion of ovarian cancer cells by atomic force microscopy

• Mengdan Chen,
• Jinshu Zeng,
• Weiwei Ruan,
• Zhenghong Zhang,
• Yuhua Wang,
• Shusen Xie,
• Zhengchao Wang and
• Hongqin Yang

Beilstein J. Nanotechnol. 2020, 11, 568–582, doi:10.3762/bjnano.11.45

• understanding the molecular mechanism regulating the relationship between the viscoelastic and tumorigenic properties in ovarian cancer cells, the microfilament density of F-actin cytoskeleton was examined by fluorescence imaging of these cells after treatment with 0.25 μM Ech for 0, 3 and 6 h (Figure 7). The

• stained with ActinGreen (KeyGEN BioTECH). A laser scanning confocal microscope (SP8, Leica) was used to image the cytoskeletal organization by F-actin. The fluorescence imaging was captured at 488 nm excitation wavelength. Moreover, the images were processed with the software Image J. Statistical analysis

Identification of physicochemical properties that modulate nanoparticle aggregation in blood

• Ludovica Soddu,
• Duong N. Trinh,
• Eimear Dunne,
• Dermot Kenny,
• Giorgia Bernardini,
• Ida Kokalari,
• Arianna Marucco,
• Marco P. Monopoli and
• Ivana Fenoglio

Beilstein J. Nanotechnol. 2020, 11, 550–567, doi:10.3762/bjnano.11.44

• absence of agonists for up to 40 min of incubation. PRP without NPs was used as the control. The data are expressed as the mean of three independent experiments. Flow cytometry fluorescence-activated cell sorting (FACS) Flow cytometry fluorescence-activated cell sorting (FACS) was used to evaluate

• reactions were stopped by the addition of PBS to a final volume of 1 mL. The mean fluorescence intensity (MFI) was read on a Beckman Coulter Cytomics FC500 flow cytometer. The experiments were repeated by adding 5 µL of ADP (10 µM). The data are expressed as the mean of three independent experiments

Luminescent gold nanoclusters for bioimaging applications

• Nonappa

Beilstein J. Nanotechnol. 2020, 11, 533–546, doi:10.3762/bjnano.11.42

• bioimaging in preclinical, clinical evaluation and patient treatment has encouraged extensive investigation to develop new imaging methods [3][4]. Among several imaging techniques, fluorescence microscopy has evolved as a widely used non-invasive method to visualize real-time biological processes with high

• spatial resolution [5][6]. The image quality of biological structures under fluorescence microscopy also depends on the performance of the fluorophores. Furthermore, bioimaging of cells and tissues faces additional challenges due to background autofluorescence generated from the intrinsic emission of

• ]. Luminescence can also be achieved via intramolecular energy transfer between an organic ligand and lanthanide metal ions through chelation [11]. Large Stokes shift, high quantum yield and long fluorescence lifetime make lanthanide complexes excellent candidates in imaging applications [12][13]. The lanthanide

Multilayer capsules made of weak polyelectrolytes: a review on the preparation, functionalization and applications in drug delivery

• Varsha Sharma and
• Anandhakumar Sundaramurthy

Beilstein J. Nanotechnol. 2020, 11, 508–532, doi:10.3762/bjnano.11.41

Interfacial charge transfer processes in 2D and 3D semiconducting hybrid perovskites: azobenzene as photoswitchable ligand

• Nicole Fillafer,
• Tobias Seewald,
• Lukas Schmidt-Mende and
• Sebastian Polarz

Beilstein J. Nanotechnol. 2020, 11, 466–479, doi:10.3762/bjnano.11.38

• . Therefore, decreased radiative recombination can be observed and increased photoswitching occurs. Time-dependent fluorescence measurements reveal the distance-dependent energy transfer dynamics. We observe much shorter lifetimes for small insulating spacers (AzoC1 and AzoC2) than for longer spacers (AzoOC4

Synthesis and enhanced photocatalytic performance of 0D/2D CuO/tourmaline composite photocatalysts

• Changqiang Yu,
• Min Wen,
• Zhen Tong,
• Shuhua Li,
• Yanhong Yin,
• Xianbin Liu,
• Yesheng Li,
• Tongxiang Liang,
• Ziping Wu and
• Dionysios D. Dionysiou

Beilstein J. Nanotechnol. 2020, 11, 407–416, doi:10.3762/bjnano.11.31

• ) spectra. UV–visible diffuse reflectance spectra were measured using a Lambda 750S UV–vis spectrophotometer (Perkin-Elmer, USA) calibrated using barium sulfate. Photoluminescence (PL) spectra were measured with a F-4600 fluorescence spectrophotometer (Hitachi, Japan) with an excitation wavelength of 400 nm

• Information File 1, Figure S1). Generally speaking, the higher the transient photocurrent density, the smaller the electrochemical impedance spectra (EIS) [33][34]. According to the time-resolved PL spectra in Figure 5d, the average fluorescence lifetime of the CuO/tourmaline composite (2.94 ns) was shortened

• , volume = 100 mL, temperature = 25 °C. Schematic illustration of the role of tourmaline in enhancing the photocatalytic activity of CuO. BET specific surface area, total pore volume, average pore size, and average fluorescence lifetime of the samples. Supporting Information Supporting Information File 66

Brome mosaic virus-like particles as siRNA nanocarriers for biomedical purposes

• Alfredo Nuñez-Rivera,
• Pierrick G. J. Fournier,
• Danna L. Arellano,
• Ana G. Rodriguez-Hernandez,
• Rafael Vazquez-Duhalt and
• Ruben D. Cadena-Nava

Beilstein J. Nanotechnol. 2020, 11, 372–382, doi:10.3762/bjnano.11.28

• fluorescence of this fluorophore, the internalization into tumor cells using this labeling technique appears to be better when compared with some previous reports [31][32][33]. The NanoOrange-loaded BMV and CCMV capsids were then incubated in MCF-7 cell cultures for 4 h to evaluate their internalization into

• the breast cancer cells. Representative confocal microscopy images showed NanoOrange fluorescence inside the cells (Figure 1A). It is important to point out that the capsids are able to internalize efficiently into tumor cells without any functionalization. The cell internalization has been quantified

• possible detachment of NanoOrange from the capsids, FITC fluorophore was covalently conjugated to the capsid surface and analyzed by confocal microscopy (Figure 2 and Figure S1, Supporting Information File 1). The confocal images showed FITC fluorescence inside the cells without colocalization of the

Poly(1-vinylimidazole) polyplexes as novel therapeutic gene carriers for lung cancer therapy

• Gayathri Kandasamy,
• Elena N. Danilovtseva,
• Vadim V. Annenkov and
• Uma Maheswari Krishnan

Beilstein J. Nanotechnol. 2020, 11, 354–369, doi:10.3762/bjnano.11.26

• systems become ineffective in delivering their cargo due to their inability to escape the endosome in cells. To investigate ability of the PVI polyplexes to escape from endosomes, their co-localization with the endosomes was investigated and the results are presented in Figure 4. The green fluorescence of

• the endosomes and the red fluorescence of the fluorophore-tagged siRNA are perfectly merged indicating that the free siRNA is unable to escape from the endosome. This is expected as it has been established earlier that double-stranded oligonucleotides tend to accumulate in the endosomal compartment

• and very few manage to reach the cytosol [25]. The polyplex-treated cells reveal several zones of red fluorescence localized at regions distinct from the green fluorescence. This suggests that a fraction of the polyplex has escaped from the endosomal compartment, which is advantageous for gene

Using gold nanoparticles to detect single-nucleotide polymorphisms: toward liquid biopsy

• María Sanromán Iglesias and
• Marek Grzelczak

Beilstein J. Nanotechnol. 2020, 11, 263–284, doi:10.3762/bjnano.11.20

• -art of advanced techniques in the field of genomics such as digital PCR, next generation sequencing (NGS), fluorescence in situ hybridization (FISH) and BEAMing. These facilitate the fast design of mutational profiles of tumor DNA, helping the prioritization of anti-cancer therapy. Although these

• solution containing plasmonic nanoparticles (from red to blue) in the presence of molecules offers an excellent tool for colorimetric sensing without the need of using advanced techniques. Similarly, selective fluorescence quenching of organic dyes or semiconducting nanoparticles by plasmonic nanoparticles

• capable of quenching fluorescence through Förster resonance energy transfer. By involving an isothermal circular amplification reaction of polymerase and NEase, the group of Chen [121] used gold nanoparticles to either quench or enhance the electrochemiluminescence of CdS films through the modulation of

Phase inversion-based nanoemulsions of medium chain triglyceride as potential drug delivery system for parenteral applications

• Eike Folker Busmann,
• Dailén García Martínez,
• Henrike Lucas and
• Karsten Mäder

Beilstein J. Nanotechnol. 2020, 11, 213–224, doi:10.3762/bjnano.11.16

• differently diluted nanoemulsions, the cells were incubated for 4 or 24 h. The cell viability was determined by a resazurin reduction assay. Therefore, 30 µL of a 0.15 mg/mL resazurin solution was added and the mixture was incubated for 2 h. Then, the fluorescence intensity was determines with the CytationTM

Rational design of block copolymer self-assemblies in photodynamic therapy

• Maxime Demazeau,
• Laure Gibot,
• Anne-Françoise Mingotaud,
• Patricia Vicendo,
• Clément Roux and
• Barbara Lonetti

Beilstein J. Nanotechnol. 2020, 11, 180–212, doi:10.3762/bjnano.11.15

• nanoparticles through disulfide bonds and conferred a sensitiveness to GSH at intracellular level. The authors showed that the intact micelles generated heat upon irradiation, thus allowing PTT, while fluorescence and ROS generation were the main deactivation processes in the case of disassembled micelles. This

• is an example of “all in one“ nanomedicine used for chemotherapy combining loading with doxorubicin, PDT and PTT. This is possible thanks to the activation of the photosensitizer and multimodal imaging using the fluorescence of the photosensitizer (near-infrared fluorescence imaging, NIRFI) and the

• released [91]. The photoactivity of the photosensitizer can also be modulated by conjugation with a quencher molecule different from the photosensitizer itself. IR780 could be used as a quencher of chlorin-e6 fluorescence in albumin-based nanosystems [107]. Upon NIR excitation and IR780 degradation chlorin

Molecular architectonics of DNA for functional nanoarchitectures

• Debasis Ghosh,
• Lakshmi P. Datta and
• Thimmaiah Govindaraju

Beilstein J. Nanotechnol. 2020, 11, 124–140, doi:10.3762/bjnano.11.11

• tiles were separated by a helical turn, which triggered the switchable motion of the device through B-to-Z-form transition, and the relative changes in position and transformation were monitored by the fluorescence resonance energy transfer (FRET) technique. Zhao and co-workers reported the design and

• xenograft tumor-bearing mice. The siRNA-conjugated DNA tetrahedron nanoarchitecture system was administered to mice by tail vein injection, and the quantitative accumulation was monitored by fluorescence molecular tomography imaging, combined with computed tomography. The imaging data showed accumulation of

The different ways to chitosan/hyaluronic acid nanoparticles: templated vs direct complexation. Influence of particle preparation on morphology, cell uptake and silencing efficiency

• Arianna Gennari,
• Julio M. Rios de la Rosa,
• Erwin Hohn,
• Maria Pelliccia,
• Enrique Lallana,
• Roberto Donno,
• Annalisa Tirella and
• Nicola Tirelli

Beilstein J. Nanotechnol. 2019, 10, 2594–2608, doi:10.3762/bjnano.10.250

• specified incubation times, i.e., 0, 2, 4, 8, 16, and 24 h. Afterwards, cells were washed three times with pre-warmed PBS and lysed in 100 µL RIPA Buffer. The total uptake (combined membrane-bound and internalized materials) was calculated from fluorescence measurements of the cell lysates using a

• -based cationic nanocarriers [40][41]. Next, we analysed the nanoparticle uptake in the two cell lines for up to 24 h; we tracked the fluorescence associated to nanoparticles in cell lysates, which accounts for both membrane-bound and internalized materials [10]. We used fluorescently labelled chitosan

• and HA, producing nanoparticles selectively containing one labelled polymer. Following either chitosan- or HA-associated fluorescence (respectively black and red symbols in Figure 5), we observed qualitatively similar uptake kinetics, which is a sign that the two components are mostly internalized

Fully amino acid-based hydrogel as potential scaffold for cell culturing and drug delivery

• Dávid Juriga,
• Evelin Sipos,
• Orsolya Hegedűs,
• Gábor Varga,
• Miklós Zrínyi,
• Krisztina S. Nagy and
• Angéla Jedlovszky-Hajdú

Beilstein J. Nanotechnol. 2019, 10, 2579–2593, doi:10.3762/bjnano.10.249

• concentration around 1.5 wt %) which correlates with the findings of Datta et al., who found that the addition of 1.5 wt % of LYS significantly increases the cell viability [30]. The two-photon microscopic images (Figure 6b) confirm the results of our viability assays. Since the cells show a red fluorescence