bluuebunny/crossref_metadata_2025 huggingface dataset:
Novel Immunopharmacological Drugs for the Treatment of Allergic Diseases
Authors: Tiligada Ekaterini , Gafarov Daria , Zaimi Maria , Vitte Joana , Levi-Schaffer Francesca
Published: September 2023

The exponential rise in the prevalence of allergic diseases since the mid-twentieth century has led to a genuine public health emergency and has also fostered major progress in research on the underlying mechanisms and potential treatments. The management of allergic diseases benefits from the biological revolution, with an array of novel immunomodulatory therapeutic and investigational tools targeting players of allergic inflammation at distinct pathophysiological steps. Prominent examples include therapeutic monoclonal antibodies against cytokines, alarmins, and their receptors, as well as small-molecule modifiers of signal transduction mainly mediated by Janus kinases and Bruton's tyrosine kinases. However, the first-line therapeutic options have yet to switch from symptomatic to disease-modifying interventions. Here we present an overview of available drugs in the context of our current understanding of allergy pathophysiology, identify potential therapeutic targets, and conclude by providing a selection of candidate immunopharmacological molecules under investigation for potential future use in allergic diseases.
(Invited) Intra- and Intermolecular Fano Resonances in Doped Semiconducting Carbon Nanotubes
Authors: Hertel Tobias , Eckstein Klaus , Müller Daniel
Published: September 2023

Electron-phonon coupling plays a key role for understanding physical phenomena such as carrier transport and superconductivity [1]. The Fano-like line shape of vibrational resonance signals in the mid infrared, sheds light on the interactions of lattice vibrations with low-energy states of the electronic absorption continuum in doped semiconducting single-wall carbon nanotubes (s-SWNTs). [2,3]. Here, we present a systematic investigation of such Fano resonances in intrinsic and doped, polymer-wrapped monochiral s-SWNT thin-films. We observe distinct resonance signals for the Raman active D- and G-bands, which acquire IR oscillator strength via coupling to the dipole-allowed Drude-like intraband continuum in doped s-SWNTs [2]. We also observe two IR-active bands in the 800 cm-1 range which are discussed in terms of the coherent intra- as well as intermolecular superposition of coupled, harmonic oscillations of electronic intraband- and different vibrational modes.

[1] M. Lazzeri et al., Phys. Rev. B, 2006, 73(15), 155426.

[2] K. H. Eckstein et al., J. Phys. Chem C, 2021, 125(10), 5700-5707.

[3] U. Fano, Phys. Rev. 1961, 124, 1866-1878.
(Invited) Proximity Induced Chiral Quantum Light Generation in Strain-Engineered WSe2/NiPS3 Heterostructures
Authors: Htoon Han
Published: September 2023

Quantum light emitters (QEs) capable of generating single photons of well-defined circular polarization could enable non-reciprocal single photon devices and deterministic spin-photon interfaces critical for realizing complex quantum networks. To date, emission of such chiral quantum light has been achieved via the application of intense external magnetic fields electrical/optical injection of spin polarized carriers/excitons, or coupling with complex photonic/meta-structures. Here we report free-space generation of highly chiral single photons from QEs created via nanoindentation of monolayer WSe2 - NiPS3 heterostructures at zero external magnetic field. These QEs emit in the 760-800 nm range with a degree of circular polarization and single photon purity as high as 0.89 and 80% respectively, independent of pump laser polarization. Scanning diamond nitrogen vacancy microscopy and temperature dependent magneto-photoluminescence studies reveal that the chiral quantum light emission arises from magnetic proximity interactions between localized excitons in the WSe2 monolayer and the out-of-plane magnetization of defects in antiferromagnetic (AFM) order of NiPS3, both of which are co-localized by the strain field associated with the nanoscale indentations.
(Invited) New Approaches for Frequency-Resolving Single Photon Detection Based on Nanoscale Systems
Authors: Leonard Francois
Published: September 2023

Single photon detectors play a key role across a number of basic science and technology applications. While progress has been made in improving performance, single photon detectors that can maintain high performance while also resolving the photon frequency are still lacking. In this presentation, I will discuss how a photodetector architecture composed of nanoscale elements that cooperatively interact with the photon field can simultaneously achieve high efficiency, low jitter, low dark count rate, and high frequency resolution. A potential physical realization of such an architecture utilizing carbon nanotubes will be presented.
(Invited) Coupled Quantum Emitters in Carbon Nanotubes
Authors: Voisin Christophe , Borel Antoine , Rapisarda Federico , Chassagneux Yannick , Selmani Mayssane , He Xiaowei
Published: September 2023

The development of covalent diazonium functionalization of carbon nanotubes brings unique opportunities in terms of original quantum sources of light. In particular, it should be possible to create a linear ensemble of closely packed single-photon sources along the carbon nanotube backbone. The physical proximity of several dopants would make it possible to couple them simultaneous to a resonant cavity mode and to induce original dynamics and light emission properties. Here, we investigate experimentally the case of a series of four quantum emitters attached to the same carbon nanotube coupled to a high finesse fiber cavity. We explore their properties through PLE, polarization and super-localization measurements and their light emission properties using time-correlation techniques and photo-luminescence decay measurements. We show that two pairs show qualitatively different behaviors in terms of spectral diffusion and luminescence saturation, which we interpret using two models of electronically coupled or uncoupled two-level systems.
(Invited) Electroluminescence from Single-Walled Carbon Nanotubes with Quantum Defects
Authors: Li Min-Ken , Riaz Adnan , Wederhake Martina , Fink Karin , Saha Avishek , Dehm Simone , He Xiaowei , Schoeppler Friedrich , Kappes Manfred , Htoon Han , Popov Valentin , Doorn Stephen , Hertel Tobias , Hennrich Frank , Krupke Ralph
Published: September 2023

Individual single-walled carbon nanotubes with covalent sidewall defects have emerged as a new class of photon sources whose photoluminescence spectra can be tailored by the carbon nanotube chirality and the attached functional group/molecule. Here we present electroluminescence spectroscopy data from single-tube devices based on (7,5) carbon nanotubes, functionalized with dichlorobenzene molecules, and wired to graphene electrodes. We observe electrically generated, defect-induced emissions that are controllable by electrostatic gating and strongly red-shifted compared to emissions from pristine nanotubes. The defect-induced emissions are assigned to excitonic and trionic recombination processes by correlating electroluminescence excitation maps with electrical transport and photoluminescence data. At cryogenic conditions additional, gate-dependent emission lines appear which are assigned to phonon-assisted hot-exciton electroluminescence from quasi-levels. Similar results were obtained with functionalized (6,5) nanotubes. We also compare functionalized (7,5) electroluminescence data with photoluminescence of pristine and functionalized (7,5) nanotubes redox-doped using gold(III) chloride solution. This work shows that electroluminescence excitation is selective toward neutral defect-state configurations with the lowest transition energy, which in combination with gate-control over neutral versus charged defect-state emission leads to high spectral purity.

Reference: Min-Ken Li et al., ACS Nano 2022 (doi: 10.1021/acsnano.2c03083)

Figure 1
Theoretical Modeling of sp3 Quantum Defects in Boron Nitride
Authors: Lee Seungyeop , Fortner Jacob , Wang YuHuang
Published: September 2023

Atomic defects in solids are intensively investigated as promising candidates for use as single photon sources. However, except for several remarkable exceptions, the atomic structures of these defects are largely unknown. We performed density functional theory calculations to predict SP3 quantum defects in boron nitride that can behave as bright emitters. The results point to possible new designs of quantum emitters in low-dimensional BN materials.
Towards Single-Molecule Analyte Sensing with Single-Walled Carbon Nanotubes
Authors: Card Matthew , Roxbury Daniel
Published: September 2023

Single-walled carbon nanotubes (SWCNTs) have been at the forefront of research for well over a decade due to their unique optical properties. Specifically, the inherent and photostable fluorescence of SWCNTs has been used to create sensitive near-infrared (NIR) sensors for a variety of target analytes, such as dopamine and cholesterol. However, most of the SWCNT sensors are employed in the solution-phase, severely limiting the efficacy due to ensemble measurements which can significantly confound any optical readout. One potential solution involves imaging individual SWCNTs deposited on a surface, unfortunately it is well known that SWCNT florescence is adversely affected by the inherently rough surfaces that are conventionally used for their observation, which emphasizes the need for a novel platform. We therefore devised a spin-coated hydrogel platform that contained SWCNTs in a single focal plane and enabled fluorescent imaging without significantly perturbing their optical properties when compared to the solution-phase. As SWCNT fluorescent microcopy is limited by diffraction, several strategies were employed to improve the sensitivity of analyte detection. When single SWCNTs longer than the diffraction limit were examined, spectral heterogeneity was observed along the length of each SWCNT, suggesting an application in single-molecule analyte detection. A common surfactant sodium deoxycholate (SDC) was investigated as an analyte as it exchanges with DNA oligonucleotides on the surface of DNA-SWCNTs, by which the kinetic response can be used to estimate DNA binding strength. We employed DNA-SWCNTs in the hydrogel platform and observed the kinetic response of individual SWCNTs in response to the addition of SDC. Importantly, the diffusion was intentionally slowed by modifying the top hydrogel layer to examine the kinetic response on a longer time scale, in contrast to the nearly instantaneous response in solution. We observed a decoupling of the spectral properties of each SWCNT, where the fluorescence intensity responded later than the emission wavelength. We then utilized a 1-dimensional diffusion model to estimate the local concentration of each SWCNT. We hypothesize that differences in the SDC functionalization morphology on SWCNTs have a significant impact on this observed effect.
(Invited) Optical Properties and Device Application of One-Dimensional Vdw Heterostructures Based on Single-Walled Carbon Nanotubes
Authors: Maruyama Shigeo
Published: September 2023

A typical one-dimensional (1D) van der Waals (vdW) heterostructure consists of SWCNT, boron nitride nanotube (BNNT), and molybdenum disulfide nanotube (MoS2NT), grown coaxially by successive chemical vapor deposition (CVD) steps [1, 2]. The coaxially nested structure based on SWCNTs, which has diverse electronic properties (metallic or semiconducting), can expand the board application possibilities of 1D vdW heterostructures [3]. By comparing the optical properties of films of BNNT@MoS2NT and SWCNT@BNNT@MoS2NT, we found strong photoluminescence (PL) from monolayer MoS2NT and quenching of PL by coupling to SWCNT through thin BNNT [4]. The inter-tube excitons are demonstrated by ultrafast optical spectroscopy [5]. The inter-tube excitons, the counterpart of inter-layer excitons for 2D heterostructures, suggest a possibility of efficient photovoltaic applications of the 1D heterostructure [6]. In addition to MoS2 nanotubes, we will discuss the growth control of WS2 and NbS2 nanotubes. A general strategy we can tune the CVD condition from 2D flake to 1D tube is proposed. The junctions of MoS2 and WS2 nanotube are also realized as the outermost layer. More specific optical properties are studied for semiconductor SWCNTs and chirality-sorted SWCNTs [7,8]. Semiconductor SWCNT or chirality-sorted SWCNT wrapped with BNNT can be regarded as the ideal building blocks of field-effect transistors (FET) [9]. We have demonstrated the radial semiconductor–insulator–semiconductor (S-I-S) tunneling heterojunction diode by using a micrometer long 1D vdW heterostructure SWCNT@BNNT@MoS2NT [10]. We will discuss a more recent array of 1D heterostructure FET devices.

Part of this work was supported by JSPS KAKENHI Grant Number JP20H00220, and by JST, CREST Grant Number JPMJCR20B5, Japan.

References:

[1] R. Xiang et al., Science
367, 537 (2020).

[2] Y. Zheng, et al, P. Natl. Acad. Sci., 118, e2107295118 (2021).

[3] S. Cambré, et al., Small, 17, 2102585 (2021).

[4] M. Liu et al., ACS Nano
15, 8418 (2021).

[5] M. G. Burdanova et al., Adv. Funct. Mater.
32, 2104969 (2022).

[6] R. Xiang, Y. Li, S. Maruyama, National Science Open, 1, 20220016 (2022).

[7] R. Zhang et al., Carbon
199, 407 (2022).

[8] C. Zhang et al., ACS Nano
16, 18630 (2022).

[9] R. Xiang, S. Maruyama, Small Sci., 1, 2000039 (2021).

[10] Y. Feng, et al., ACS Nano, 15, 5600 (2021).
(Invited) Discussion on Preparation of Single-Walled Carbon Nanotubes for High-Performance Electronics
Authors: Li Yan
Published: September 2023

The unique structure and outstanding properties of single-walled carbon nanotubes (SWCNTs) make them top candidates for future high-performance electronics. Highly pure (>99.9999%) and dense (>125tubes/micron) SWCNTs are desired to present performance surpassing silicon-based devices and chips. Material preparation is the prerequisite of electronic applications. Selective synthesis, purification/sorting, and controlled assembling are procedures that associated with pathways to obtain SWCNT materials for high-performance electronics. However, it’s still not clear that what is the feasible strategy. More discussions and critical thinkings are in urgent need. I will try to review some of the recent developments in the field and discuss the possible directions in future study.

References:

A. D. Franklin. The road to carbon nanotube transistors. Nature 2013, 498, 443.

F. Yang, M. Wang, D. Zhang, J. Yang, M. Zheng, Y. Li. Chirality Pure Carbon Nanotubes: Growth, Sorting, and Characterization. Chemical Reviews 2020, 120 (5), 2693.

Y. Chen, M. Lyu, Z. Zhang, F Yang, Y. Li. Controlled preparation of single-walled carbon nanotubes as material for electronics. ACS Central Science 2022, 8, 1490.

A. D. Franklin, M. C. Hersam, H.-S. P. Wong. Carbon nanotube transistors: Making electronics from molecules. Science 2022, 378, 726.

Figure 1
(Invited) Reaction of Elemental Sulfur at the Surfaces of Carbon Nanotubes and Graphene
Authors: Martel Richard , Sprocq Simon , Haddad Elie , Schué Leonard , Pimonov Vladimir , Dolle Mickael , Rochefort Alain
Published: September 2023

The chemical functionalization of nanocarbons is key for ensuring their processability in solution and to derive new surface functionalities for applications. For this respect, the oxidation reactions of graphene and carbon nanotubes by strong oxidants is nowadays among the most significant to both clean the raw materials and add functional groups, such as what is present at the surfaces of the graphene oxides (e.g. GO and RGO) and oxidized carbon nanotubes. Because of the harsh conditions (e.g. strong acids), the oxidation process gives rise to a great variability of surface groups (e.g. epoxide, hydroxyl, carbonyl) from which the chemical behavior is rather complex. The reaction also leaves acidic residues in quantities that can be environmentally hazardous. Here, we explored an alternative approach to functionalize carbon nanotubes and graphene using a direct reaction with elemental sulfur. Depending on the conditions, we find that the sulfur atoms can modify irreversibly the surfaces with a covalent episulfide functions. The sulfur reaction is extensive, and it is therefore presented here as a green alternative for the chemical processing of nanocarbon materials.
(Invited) Diameter-Dependent Stacking of Squaraine Dye Molecules inside Chirality-Sorted Single-Wall Carbon Nanotubes
Authors: Wenseleers Wim , Forel Salome , van Bezouw Stein , Campo Jochen , Cambre Sofie , Li Han , Wieland Laura , Flavel Benjamin S
Published: September 2023

Filling of single-wall carbon nanotubes (SWCNTs) with organic dye molecules is a promising strategy to add new functionalities, for instance by aligning dipolar dyes in a one-dimensional (1D) head-to-tail coupled chain to obtain a giant enhancement of their nonlinear optical response,[1] or by photo-sensitizing the tubes in new wavelength ranges by excitation energy transfer (EET) from the dye to the SWCNTs, useful for photo-conversion applications.[2] The 1D stacking of molecules inside SWCNTs modulates both the properties of the molecules and of the SWCNTs. We found that the EET of squaraine-dye-filled SWCNTs reveals a pronounced SWCNT-diameter-dependence of the dye absorption, indicating a diameter-dependent stacking. By performing IR fluorescence excitation spectroscopy on a range of chirality-enriched samples of dye-filled SWCNTs with different chirality distributions, each shifted dye absorption wavelength observed through the EET can be unambiguously assigned to a specific encapsulating SWCNT chirality.[3] This reveals a systematic trend with diameter that can be associated with the J-aggregate- and H-aggregate-like interactions expected in close-packed single- and double-file stackings, as corroborated by a simple geometric model, and enables tuning of the optical properties of the 1D molecular arrays through the selection of proper SWCNT diameters.

[1] S. Cambré, J. Campo, C. Beirnaert, C. Verlackt, P. Cool, W. Wenseleers, Nature Nanotechnol.
10(3) 248-252 (2015).

[2] S. van Bezouw, D.H. Arias, R. Ihly, S. Cambré, A.J. Ferguson, J. Campo, J.C. Johnson, J. Defillet, W. Wenseleers, J.L. Blackburn, ACS Nano
12(7) 6881-6894 (2018).

[3] S. Forel, H. Li, S. van Bezouw, J. Campo, L. Wieland, W. Wenseleers, B.S. Flavel, S. Cambré, Nanoscale
14, 8385-8397 (2022).
(Invited) Advancing Characterization and Control of (n,m) Separations of Surfactant-Dispersed Single-Wall Carbon Nanotubes
Authors: Sims Christopher , Fagan Jeffrey
Published: September 2023

Aqueous-phase processing of dispersed single-wall carbon nanotubes (SWCNTs) to isolate highly pure populations such as single (n,m) species or length resolved populations is of great interest to be scaled for advancing scientific investigations and commercial applications. Although many methods for (n,m) separation have been advanced, species refinement through surfactant-controlled aqueous two-polymer phase extraction (ATPE) is a particularly flexible, tailorable, and scalable route. However, better characterization of the separation conditions for different species, diameter ranges and lengths of SWCNTs can improve the ability to rapidly resolve different populations. In this talk I will present an advance in characterization of extraction conditions in ATPE using a continuous titration methodology to sweep surfactant and other solution component concentrations as a function of time while monitoring (n,m) specific fluorescence. This improvement is enabling dramatically enhanced throughput of screening multi-surfactant and modulating solution component effects on the ATPE partitioning and revealing simple orthogonal surfactant concentration steps to distinguish between traditionally difficult to separate species. Notably, an approximate order of magnitude improvement in resolution is simultaneously achieved, revealing previously unseen complexity and demonstrating direction independent reversibility of the underlying surfactant competition process. Examples of new effects and comparison to literature data will be presented.
(Invited) Efficient Inner-to-Outer Wall Energy Transfer in Highly Pure Double-Wall Carbon Nanotubes Revealed by Detailed Spectroscopy
Authors: Cambre Sofie , Erkens Maksiem , Levshov Dmitry , Avramenko Marina , Forel Salome , Wenseleers Wim , Li Han , Flavel Benjamin S , Fagan Jeffrey , Popov Valentin , Flahaut Emmanuel
Published: September 2023

The coaxial stacking of two single-wall carbon nanotubes (SWCNTs) into a double-wall carbon nanotube (DWCNT), forming a so-called one-dimensional van der Waals structure, leads to synergetic effects that dramatically affect the optical and electronic properties of both layers [1]. In this work, we explore these effects in purified DWCNT samples by combining absorption, wavelength-dependent infrared fluorescence−excitation (PLE), and wavelength-dependent resonant Raman scattering (RRS) spectroscopy. Purified DWCNTs are obtained by careful solubilization that strictly avoids ultrasonication [2] or by electronic-type sorting [3], both followed by a density gradient ultracentrifugation to remove unwanted SWCNTs that could obscure the DWCNT characterization [2]. Chirality-dependent shifts of the radial breathing mode vibrational frequencies and transition energies of the inner and outer DWCNT walls with respect to their SWCNT analogues are determined by advanced two-dimensional fitting of RRS and PLE data of DWCNT and their reference SWCNT samples. This exhaustive data set verifies that fluorescence from the inner DWCNT walls of well-purified samples is severely quenched, as previously evidenced in single-tube experiments [4]. Moreover, we find that this quenching occurs through efficient energy transfer from the inner to the outer DWCNT walls [5]. Combined analysis of the PLE and RRS results further reveals that this transfer is dependent on the inner and outer wall chirality, and we identify the specific combinations dominant in our DWCNT samples. These obtained results demonstrate the necessity and value of a combined structural characterization approach including PLE and RRS spectroscopy for bulk DWCNT samples.

[1] S. Cambré et al, Small 2021, 17, 2102585

[2] M. Erkens et al, Carbon 2021, 185, 113

[3] H. Li et al, Nature Nanotechnol. 2017, 12, 1176

[4] D. Levshov et al, Phys. Rev. B 2017, 96, 195410

[5] M. Erkens et al, ACS Nano 2022, 16, 16038
A Generic Covalent Functionalization Concept for Near-Infrared Fluorescent Carbon Nanotube Biosensors
Authors: Metternich Justus , Sistemich Linda , Herbertz Svenja , Kruss Sebastian
Published: September 2023

Biosensors are powerful tools with wide applications in basic research and biomedical diagnostics. In the last decades, the use of nanomaterials decorated with biological recognition units have attracted significant attention and reformed the field. However, this development requires substantial input from the chemical sciences.

In this context, semiconducting single-walled carbon nanotubes (SWCNTs) are versatile near infrared (NIR, 870 – 2400 nm) emitting fluorophores. They have been non-covalently modified to create sensors that change their fluorescence when interacting with biomolecules. However, non-covalent chemistry has several disadvantages and prevents a consistent way to signal transduction and rational design. Here, we introduce a widely applicable covalent approach to create molecular sensors without destroying the fluorescence in the NIR. For this purpose, a new class of quantum defects in the SWCNT lattice is used to bind biomolecules and to guarantee colloidal stability. To showcase the potential of this approach we demonstrate sensing for different classes of biomolecular analytes (nucleic acids, proteins as well as macromolecular complexes). We analyze sensitivity and selectivity of this recognition approach and present a straightforward way for the generation of novel sensors. In summary, we introduce a novel quantum defect-based covalent functionalization approach of fluorescent SWCNTs with great potential for biosensing.
Polarization Resolved Fluorescence Detection of Carbon Nanotube Corona Phases
Authors: Jin Xiaojia , Kuehne Matthias , Gong Xun , Ucko Amandine , Strano Michael S.
Published: September 2023

Circular dichroism measures how chiral particles absorb right- and left- circularly polarized light differently to distinguish pairs of enantiomers. It can also elucidate differential photoabsorption of chiral fluorescent species via their emissions. However, this method has generally been restricted to bulk samples. Hence, these methods conceal information on the specific chiroptical response of a single particle. Furthermore, circular dichroism has been restricted in time- resolution as well as spectral range. In this work, we observed fluorescence detected circular dichroism (FDCD) of individually deposited single walled carbon nanotube (SWNT) corona. A custom-built setup compromising a linear polarizer (LP) and a quarter waveplate (QWP) was used to induce circularly polarized light (CPL). The light polarization state at the sample plane was analyzed using Stoke’s parameter. Experimental results showed that linear dichroism of the dichroic filter inside the microscope changes the polarization state of the incoming beam drastically, and thus inducing elliptically polarized light at the sample plane. A liquid crystal variable retarded (LCVR) was used to correct the polarization state of light and yield CPL at the sample plane. Singly-dispersed SWNT with different wrapping polymers were deposited onto a glass substrate. Alternating cycles of right- and left-handed circularly polarized light was delivered to excite the sample. The fluorescence intensities of each individual SWNT were tracked. The dissymmetry (g) parameters: g = 2(IL-IR)/(IL+IR) (where I

L
and I

R
are the measured fluorescence intensities with left and right circularly polarized light, respectively) were analyzed from the fluorescent signals to understand photoabsorption differences. A non-zero value of dissymmetry parameter provides information on how the corona modulates SWNT photoluminescence, an outcome not observable by bulk characterization methods. This observation can potentially enable the measurement of chiral species local interactions without a separations process.
Prediction of Mycotoxin Response of DNA-Wrapped Nanotube Sensor with Machine Learning
Authors: Rabbani Yahya , Behjati Sara , Lambert Benjamin , Sajjadi Sayyed Hashem , Shariaty-Niassar Mojtaba , Boghossian Ardemis Anoush
Published: September 2023

DNA-wrapped single-walled carbon nanotubes (SWCNTs) have demonstrated great versatility in their use as optical sensors. SWCNTs emit a near-infrared fluorescence that is responsive to even the slightest changes in the nanotube environment, enabling sensors that can respond to single-molecule fluctuations within the vicinity of their surfaces. The fluorescence response and surface interactions of these sensors are determined by the DNA wrapping sequence. However, the lack of information on the relationship between the DNA sequence and its effect on the SWCNT fluorescence remains a bottleneck for designing sequences that are specific to analytes of interest. We have recently demonstrated the use of directed evolution to control the fluorescence response of SWCNTs through DNA design. Iterative cycles of DNA mutation, screening, and selection allowed us to evolve sequences that yield DNA-wrapped SWCNT sensors with a desired fluorescence response to mycotoxins.

In this work, we apply the screening results of the DNA libraries used in this approach to train machine learning (ML) algorithms. Artificial neural network (ANN) and support vector machine (SVM) methods were used to predict the response of ssDNA-SWCNT sensors to a specific mycotoxin. The reliability of these models was further assessed through cross-validation. The ANN and SVM models with cross-validation were able to accurately classify the various DNA sequences as yielding either a high or low fluorescence response with an accuracy of 73 and 81%, respectively. The models were further used to predict the performance of alternative DNA sequences outside the initial training dataset, using the Hierarchy and k-means
++
clustering methods to evaluate the similarity and dissimilarity of each DNA sequence. Compared to the SVM model, the ANN model showed an improved ability to predict high responses for dissimilar DNA sequences. We further applied a combinatorial approach based on SVM and ANN models to design new DNA sequences for improving sensor performance. The success of this approach was validated experimentally, demonstrating the rational design of improved sensors with 95% prediction accuracy.

The application of ML algorithms to directed evolution libraries of DNA thus allows one to accurately map the performances of these sensors within a particular sequence space. The computational success of this mapping provides a framework for replacing current empirical approaches with the rational design of DNA sequences for SWCNT sensing.

Keywords: Nano Biosensor, DNA-SWCNT, Mycotoxin, Machine learning, Directed evolution method
Understanding Oligonucleotide Hybridization and the Role of Anchoring on the Single-Walled Carbon Nanotube Corona Phase for Viral Sensing Applications
Authors: Cui Jianqiao , Gong Xun , Cho Soo-Yeon , Jin Xiaojia , Yang Sungyun , Strano Michael S.
Published: September 2023

Semiconducting single-walled carbon nanotubes (SWCNTs) with tailored corona phases (CPs), or surface adsorbed molecules, have emerged as a promising interface for sensing applications. The adsorption of an analyte can be specifically transduced as a modulation of their band gap near-infrared (nIR) photoluminescence (PL). One such CP ideal for this purpose is single-stranded DNA (ssDNA), where subsequent sequence dependent hybridization can result in PL emission wavelength shifts. Due to ssDNA adsorption to the SWCNT surface, the resultant non-canonical hybridization and its effect on SWCNT photophysical properties are not well understood. In this work, we study 20- and 21-mer DNA and RNA hybridization on the complementary ssDNA-SWCNT CP in the context of nucleic acid sensing for SARS-CoV-2 sequences as model analytes. We found that the van’t Hoff transition enthalpy of hybridization on SWCNT CP was -11.9 kJ mol-1, much lower than that of hybridization in solution (-707 kJ mol-1). We used SWCNT solvatochromism to calculate the solvent exposed surface area to indicate successful hybridization. We found that having a 30-mer anchor region in addition to the complementary region significantly improved PL response sensitivity and selectivity, with (GT)15 anchor preferred for RNA targets. Coincubation of ssDNA-SWCNT with analyte at 37°C resulted in faster hybridization kinetics without sacrificing specificity. Other methods aimed to improve CP rearrangement kinetics such as bath sonication and surfactant additions were ineffective. We also determined that target sequence choice is important as secondary structure formation in target is negatively correlated with hybridization. Best performing CPs showed detection limits of 11 nM and 13 nM for DNA and RNA targets respectively. Finally, we simulated sensing conditions using saliva environment, showing sensor compatibility in biofluids. In total, this work elucidates key design features and processing to enable sequence specific hybridization on ssDNA-SWCNT CP.
Guanine Functionalization of SWCNTs Using Metalloporphyrin Photosensitizers
Authors: Alizadehmojarad Ali A. , Bachilo Sergei M. , Weisman R. Bruce
Published: September 2023

Chemical modifications of single-wall carbon nanotubes (SWCNT) have opened new areas in the creation of quantum defects and the tailoring of optical properties for these one-dimensional semiconducting materials. Recent research has revealed a novel and controllable chemical functionalization reaction in which guanine nucleobases of ssDNA coatings react covalently with the SWCNT side wall in the presence of singlet oxygen. Generation of singlet oxygen through photosensitizer optical excitation is a key part of this process. To further explore guanine functionalization of SWCNTs, we have investigated reaction kinetics under various conditions. We replaced the rose bengal photosensitizer by metalloporphyrin dyes. These have greater photostability and more intense and shorter wavelength absorptions, allowing them to be used at micro- to nanomolar concentrations and leaving a wider spectral transparency window for reaction monitoring. Excitation was at 405 nm. Our kinetic studies show that the rates of change of E11 and E22 energies depend linearly on sensitizer concentration, which implies that guanine functionalization is a first order reaction with respect to singlet oxygen. Using a series of oligos with the same length but different guanine contents, we find E11 spectral shifts that increase sub-linearly to an asymptotic value. To help understand the structure of the guanine covalent adduct, we also performed semi-empirical quantum chemistry simulations. These suggest that the lowest energy structure is bonded to two adjacent carbon atoms of the SWCNT sidewall, and that reaction exothermicity is larger for smaller diameter nanotubes. Computations will also be presented for presumed intermediate adducts of guanine peroxide bonded to (6,5) SWCNTs in different orientations relative to the nanotube axis.
(Invited) Carbon Nanotube Photoluminescence for Cancer Research and Diagnosis
Authors: Heller Daniel A. , Kim Mijin , Chen Chen , Wang YuHuang , Zheng Ming , Gwynne Declan
Published: September 2023

New technologies are needed for the early detection of cancer and the identification of therapeutic vulnerabilities in cancers. Our laboratory develops optical nanosensor technologies using carbon nanotubes, including sensors that identify disease fingerprints in serum, diagnostic implants to facilitate longitudinal detection of cancer biomarkers, and assays for cancer drug development. These methods employ the photoluminescence of single-walled carbon nanotube (SWCNTs) and covalent sp3 quantum well defects on SWCNTs, aka organic color centers (OCCs), that introduce new chemical sensitivities. To introduce new detection technologies using OCC-modified SWCNTs, we developed new supramolecular functionalization methods, as well as new types of optical instrumentation to detect changes in near-infrared emission within biological and clinical samples. We harnessed OCC-modified SWCNTs for the detection of metabolic changes in live cells and tissues, disease biomarkers in situ via implants, and overall disease states, aided by machine learning processes.
Raman Characterization of Guanine Functionalized SWCNTs
Authors: Soltani Nima , Bachilo Sergei M. , Weisman R. Bruce
Published: September 2023

Single-walled carbon nanotubes (SWCNTs) have unique photophysical properties that render them an important class of materials for future nanoelectronics and bio-nano sensor applications. A method was recently discovered for making spatially patterned modifications to SWCNT band gaps and thereby modulating their electronic and optical properties in a controlled manner. The reaction used for this is called guanine functionalization.1 It is achieved by generating singlet oxygen in a dispersion of SWCNTs coated with single-stranded DNA, resulting in covalent bond formation between the guanine nucleobases in the DNA coatings and the nanotube sidewalls. Each of the many covalently bonded guanine sites acts as a weak exciton trap, causing red-shifted SWCNT emission and absorption spectra. Fluorescence spectroscopy shows that the extent of guanine functionalization can depend strongly on SWCNT structure, but spectral broadening can hamper the precise deconvolution of emission features of different (n,m) species. To track such covalent functionalization through Raman scattering, the D to G band ratios are commonly used as a measure of sp3 defect density and therefore of the functionalization extent. However, this conventional Raman method cannot show which (n,m) species in unsorted samples have been functionalized, because they all contribute to the D and G band signals.

We will describe a novel Raman analysis based on the relative intensities of bands that have shifts located between the RBM and D regions. These Raman features are found to be diameter-specific, allowing estimation of (n,m)-resolved functionalization extents in unsorted SWCNT samples. In addition, we will present an assignment and interpretation of the relevant Raman features.

Zheng, Y.; Bachilo, S. M.; Weisman, R. B., Controlled patterning of carbon nanotube energy levels by covalent DNA functionalization. ACS Nano
2019,
13, 8222-8228.
(Invited) Recent Progress in Carbon Nanotube Sorting by DNA
Authors: Zheng Ming
Published: September 2023

DNA-wrapped single-wall carbon nanotubes (DNA-SWCNT) have a number of utilities. Sorting DNA-SWCNTs have been extensively studied by us and others. However, reported sorting procedures are not widely adopted by other labs. In this talk I will report some recent effort we have made in streamlining DNA-SWCNT sorting. It is our hope that the simplified procedure can be more easily adopted by others for various applications.
(Invited) Chiral Bilayer Nanographenes: A New Family of Carbon Nanostructures
Authors: Martin Nazario , Izquierdo-García Patricia , Fernández Jesús Manuel
Published: September 2023

Chirality is an important and fascinating concept which has not been properly addressed in nanocarbons science.1 We have previously reported the first inherently chiral bilayer nanographene with a helicene linker, both as the racemate and the M isomer.2,3 By extending precedented [6]helicene starting material, we obtained an unprecedented chiral nanographene comprised of two hexa-peri-hexabenzocoronene (HBC) layers fused to a [10]helicene . Furthermore, we have increased the family of bilayers by using the respective [5] and [7]helicenes, affording bilayers with [9] and [11]helicenes, respectively. These nanographenes are appealing systems for the study of further chemical reactions including redox reactions.4 In this presentation, the recent findings on this singular family of chiral nanographenes showing remarkable CPL values, as well as their less known outstanding photophysical properties will be discussed.

Acknowledgements

The author acknowledge support from the European Research Council (ERC) Synergy Grant “TOMATTO” (Project 951224).

References

1. J. M. Fernández-García, P. J. Evans, S. Filippone, M. A. Herránz, N. Martín, “Chiral Molecular Carbon Nanostructures”, Acc.
Chem. Res.
2019, 52, 1565-1574.

2. P. J. Evans, J. Ouyang, L. Favereau, J. Crassous, I. Fernández, J. Perles Hernáez, N. Martín "Synthesis of a Helical Bilayer Nanographene" Angew. Chem. Int. Ed.
2018, 57, 6774 –6779.

3. J. M. Fernández-García, P. Izquierdo-García, M. Buendía, S. Filippone, N. Martín. “Synthetic chiral molecular nanographenes: the key figure of the racemization barrier”, Chem. Commun. 2022, 58, 2634–2645.

4. Z. Zhou, J. M. Fernández-García, Y. Zhu, P. J. Evans, R. Rodríguez, J. Crassous, Z. Wei, I. Fernández, M. A. Petrukhina, N. Martín. "Site-Specific Reduction-Induced Hydrogenation of a Helical Bilayer Nanographene with K and Rb Metals: Electron Multiaddition and Selective Rb+ Complexation", Angew. Chem. Int. Ed.
2022, 61, e20211574.
(Invited) Donor-Acceptor Interaction in Two-Dimensional Materials
Authors: Imahori Hiroshi
Published: September 2023

Two-dimensional materials have drawn significant attention because of their unique electronic properties. In particular, donor-acceptor interaction at the interface are one of the state-of-the-art topics for energy and optoelectronics applications. In this talk I will give an overview of our studies on their photophysical and photoelectrochemical properties.

[1] J. Baek, T. Umeyama, W. Choi, Y. Tsutsui, H. Yamada, S. Seki, H. Imahori, Chem. Eur. J., 24, 1561-1572 (2018).

[2] T. Umeyama, T. Ohara, Y. Tsutsui, S. Nakano, S. Seki, H. Imahori, Chem. Eur. J., 26, 6726-6735 (2020).

[3] T. Umeyama, H. Xu, T. Ohara, Y. Tsutsui, S. Seki, and H. Imahori, J. Phys.
Chem. C, 125, 13954-13962 (2021).
(Invited) Hybrid Nanodevices for Technology and Fun
Authors: García Pérez Cristina , García Pérez Julia , Marzoa Victor , Caballero Gabriel , Martínez Sandra , Sánchez Toural Juan Luis , Calero de Ory Marina , Rodriguez David , Magaz Maite , Jiménez-Urbanos Fernado , Acebrón María , Rodríguez Osorio Manuel , Cánovas Enrique , Menghini Mariela , Gómez Alicia , Bernardo-Gavito Ramón , Granados Daniel
Published: September 2023

Two-dimensional materials like graphene or transition metal dichalcogenides have remarkable properties, making them very attractive from a technological point of view and incredibly fun to work with. The intrinsic properties of 2D materials change drastically when going from the bulk into the true 2D limit, where they exhibit exotic quantum properties. While many groups have focused on studying and exploiting these materials, very little work has been devoted to engineering their intrinsic properties. The “all-surface” nature makes device fabrication complex, and so far, only the most conventional nanofabrication or tailoring routes have been explored. In this talk, I will present novel routes currently under exploration in our group to tailor and exploit the properties of TMDS and MOF devices based on mechanical deformation or physical nanopatterning.

Also, the integration of 2D materials into superconducting circuits can lead to novel technological applications of interest for photon and radiation detectors or quantum computing.

In this talk, I will present some results concerning the development of retroreflectors based on MoS2 oscillating membranes and how they can be turned into electroluminescent diodes. I will also present the tailoring of conductive channels on MoS2 FET devices. Preliminary results on lateral PN homo-junctions, memristive field-effect transistors and photonic crystal cavities will also be presented. I will present preliminary results on the integration of MOF into Hall bar structures for metrology applications. To finish, I will also present results on the integration of Graphene and MoS2 onto Superconducting nanowire single photon detectors.

Figure 1
(Invited) Discovery of Longer Fullertubes: From Synthesis to Isolation
Authors: Bourret Emmanuel , Dorn Harry , Stevenson Steven
Published: September 2023

Our recent laboratory findings are resulting in a growing list of newly discovered molecules within fullertube families. We are now isolating these individual fullertubes of increasing length in pure and pristine form. We now observe solubility of these fullertubes in organic solvents; hence it is unnecessary to use polymer wrapping or external derivatization that destroys the pristine fullertubular belt with pendant soluble groups. Initial purification and seminal characterization experiments for fullertubes in JACS, Angewandte Chemie, and Nanoscale (2020-2022) are generating excitement for application development. Likewise, investigations into the fundamental science of new fullertubes are also gathering momentum as scientists curiously and eagerly await their first characterization.

For historical context, the timeline of laboratory purified and unfunctionalized (pristine) fullertubes is [5,5] C90-D5h(1) in 2010, [5,5] C100-D5d(1) in 2020, and [5,5] C120-D5d(1) in 2022. A recurring question asked to me at conferences is “To what lengths can fullertubes be extended?” For this reason, I will discuss our most recent findings and explorations into longer fullertubes with higher aspect ratios.

Figure 1
(Invited) Derivatizing Fullerenes and Metallofullerenes for Biomedicine
Authors: Zhang Jianyuan , Biswas Rohin , Li Yanbang
Published: September 2023

Fullerenes and metallofullerenes are excellent building blocks for biomedicines due to their carbon-based structures that allows for biocompatible materials being built with robust C-C covalent bonds. The hexakis-Bingel reaction can introduce up to 12 functional groups onto one C60 core and provide a versatile platform for molecularly precise, “nanoparticle-like” functional materials. In this presentation we hope to report our recent utilization of the hexakisadduct platform in biomedical applications. In the first study we investigated the anti-oxidative behavior of a series of C60 derivatives, where the hexakisadduct turned out to be an excellent reactive oxygen species scavenger. Then we exemplify the ligand introduction to the hexakisadduct core with Gd metallofullerens, which leads to a series of structurally defined, efficient and safe MRI contrast agents.
(Invited) Precise Evaluation of Functional Group Distribution and Reaction Yield for Chemically Treated Carbon Nanohorns by Highly Sensitive SEM-EDS
Authors: Nakajima Hideaki , Okazaki Toshiya
Published: September 2023

Single-walled carbon nanohorns (CNHs) have great potential in diverse applications such as catalyst support, energy conversion, and drug carriers. Although chemical functionalization of CNHs is critical for these applications, they inherently form robust spherical “dahlia-like” aggregates, which may inhibit chemical reactivity. Herein, highly sensitive energy-dispersive X-ray spectrometry (EDS) analysis in scanning electron microscopy (SEM) is employed to elucidate the functional group distribution and the reaction yield of CNH dahlia aggregates. First, the technique clearly visualizes the elemental distribution associated with the functional groups on dahlia structures with a sufficient spatial resolution of <10 nm.1 The result exposes that the outer surface of an individual aggregate is functionalized while the inner core remains almost unreacted. Second, the SEM-EDS precisely assesses the reaction yield for functionalized CNHs.2 The sensitive elemental analysis enables the evaluation of functionalization efficiency for sequentially grown polyamidoamine dendrimers on CNH surface, which consistently explains the change of chemical structure according to the reaction process. The details about the functionalization mechanism on CNH surface will be discussed in the conference.

[1] H. Nakajima, T. Morimoto, K. Kobashi, M. Zhang, I. K. Sideri, N. Tagmatarchis, and T. Okazaki, Outer-Surface Covalent Functionalization of Carbon Nanohorn Spherical Aggregates Assessed by Highly Spatial-Resolved Energy-Dispersive X-ray Spectrometry in Scanning Electron Microscopy, J. Phys. Chem. C
2020, 124, 25142-25147.

[2] H. Nakajima, K. Kobashi, C. Stangel, T. Morimoto, M. Zhang, N. Tagmatarchis, and T. Okazaki, Step-by-step Characterization of a Series of Polyamidoamine Dendrimers on Carbon Nanohorn Surface, submitted.