Bright Fluorescent Nanodiamonds: No Photobleaching and Low Cytotoxicity

No-interfered and visual evaluation of global warming impacts on phytoplankton-based copper bioavailability and then carbon sequestration

Global warming has an increasingly serious impact on the ecological environment. Copper bioavailability plays an important physiological role in revealing the mechanism of carbon cycle, photosynthesis, and respiration. Here we reported a multifunctional carbon quantum dots fluorescence probe for no-interfered and visual determination of phytoplankton-based intracellular Cu(II), glucose, and reactive oxygen species (ROS). Glucose and ROS were explored to reflect the change in primary biomass and carbon sequestration. H2O2 is acted as the standard material of ROS, and the fitting parameter for glucose and H2O2 concentrations was 0.42(r = 0.9972). Both glucose, ROS, and Cu2+ detection have advantages of wide linear range (24.8-3.96 × 105 μg/L, 6-9.6 × 105 ng/L and 5-15 × 103 nmol/L, respectively), high precision (1.22 %, 6.38 %, and 7.37 %, respectively), and low detection limit (86.7 ng/L, 5.32 ng/L, and 0.367 nmol/L, respectively). Cu2+ uptake was increased with the increasing of temperature, and the copper bioavailability in increasing order was Cu-PorPhyr > Cu-phthalate > Cu-EDTA. There were significant positive correlation between glucose and Cu2+(r = 0.9943). Copper bioavailability would directly affect the carbon sequestration, i.e., when the concentration of intracellular copper increases by 1 mg/L, the content of intracellular glucose increases by 412 mg/L approximately, equally to 2.47 g/L of carbon dioxide was fixed.

A novel treatment approach using vitamin B12-conjugated sericin for mitigating nanodiamond-induced toxicity in darkling beetles

The escalating use of nanodiamonds (NDs) has raised concerns about their ecotoxicological impact, prompting exploration of therapeutic interventions. This paper pioneers the examination of Vitamin B12-conjugated sericin (VB12-SER) as a potential therapeutic approach against ND-induced toxicity in darkling beetles (Blaps polychresta). The study analyzes mortality rates and organ-specific effects, covering the testis, ovary, and midgut, before and after treatments. Following exposure to 10 mg NDs/g body weight, within a subgroup of individuals termed ND2 with a mortality rate below 50%, two therapeutic treatments were administered, including pure sericin (SER) at 10 mg/mL and VB12-SER at 10.12 mg/mL. Consequently, five experimental groups (control, SER, ND2, ND2+SER, ND2+SER+VB12) were considered. Kaplan-Meier survival analysis was performed to assess the lifespan distribution of the insects in these groups over a 30-d period. Analyses revealed increased mortality and significant abnormalities induced by NDs within the examined organs, including cell death, DNA damage, enzyme dysregulation, antioxidant imbalances, protein depletion, lipid peroxidation, and morphological deformities. In contrast, the proposed treatments, especially (ND2+SER+VB12), demonstrated remarkable recovery, highlighting VB12-conjugated SER's potential in mitigating ND-triggered adverse effects. Molecular docking simulations affirmed binding stability and favorable interactions of the VB12-SER complex with target proteins. This research enhances understanding of NDs' effects on B. polychresta, proposing it as an effective bioindicator, and introduces VB12-conjugated SER as a promising therapeutic strategy in nanotoxicological studies.

Advances of Fluorescent Nanodiamond Platforms for Intracellular and On-Chip Biosensing

Intracellular and extracellular sensing of physical and chemical variables is important for disease diagnosis and the understanding of cellular biology. Optical sensing utilizing fluorescent nanodiamonds (FNDs) is promising for probing intracellular and extracellular variables owing to their biocompatibility, photostability, and sensitivity to physicochemical quantities. Based on the potential of FNDs, we outlined the optical properties, biocompatibility, surface chemistry of FNDs and their applications in intracellular biosensing. This review also introduces biosensing platforms that combine FNDs and lab-on-a-chip approaches to control the extracellular environment and improve sample/reagent handling and sensing performance.

Synthesis and Functionalization of Biodegradable Second Harmonic Generation Nanoprobes for Cell Targeting

Optical imaging technologies and cell targeting have played a major role in detecting and treating diseases such as cancer. Bioharmonophores are optical imaging nanoprobes composed of biodegradable polymer-encapsulated, self-assembling triphenylalanine peptides. They produce a strong second harmonic generation (SHG) signal, a non-linear optical process in which two photons directed at a non-centrosymmetric medium combine to form a new photon with twice the energy. Bioharmonophores demonstrate superior optical properties compared to fluorescent probes and, unlike previously developed inorganic SHG nanoprobes, are both biocompatible and biodegradable. Here, we present a protocol providing five detailed procedures that describe (1) synthesis of bioharmonophores; (2) embedding and imaging of the synthesized SHG nanoprobes in polyacrylamide gel; (3) functionalization of bioharmonophores with thiol-containing polyethyleneglycol; (4) subsequent click chemistry to target cancer cells; and (5) imaging of functionalized bioharmonophores endocytosed by cancer cells using two-photon microscopy. Bioharmonophores hold great potential as clinical contrast agents due to their optical features and could be used in the future as an innovative approach to cancer treatment using targeted high-resolution optical imaging. © 2024 The Author(s). Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Synthesis of bioharmonophores Basic Protocol 2: Imaging of bioharmonophores in polyacrylamide gel Basic Protocol 3: Functionalization of bioharmonophores with thiol-PEG Basic Protocol 4: Functionalization of thiol-PEGylated bioharmonophores with peptides Basic Protocol 5: Targeting of cancer cells with functionalized bioharmonophores.

Designing functionalized nanodiamonds with hyaluronic acid-phospholipid conjugates for enhanced cancer cell targeting and fluorescence imaging capabilities

Nanomedicine aims to develop smart approaches for treating cancer and other diseases to improve patient survival and quality of life. Novel nanoparticles as nanodiamonds (NDs) represent promising candidates to overcome current limitations. In this study, NDs were functionalized with a 200 kDa hyaluronic acid-phospholipid conjugate (HA/DMPE), enhancing the stability of the nanoparticles in water-based solutions and selectivity for cancer cells overexpressing specific HA cluster determinant 44 (CD44) receptors. These nanoparticles were characterized by diffuse reflectance Fourier-transform infrared spectroscopy, Raman spectroscopy, and photoluminescence spectroscopy, confirming the efficacy of the functionalization process. Scanning electron microscopy was employed to evaluate the size distribution of the dry particles, while dynamic light scattering and zeta potential measurements were utilized to evaluate ND behavior in a water-based medium. Furthermore, the ND biocompatibility and uptake mediated by CD44 receptors in three different models of human adenocarcinoma cells were assessed by performing cytofluorimetric assay and confocal microscopy. HA-functionalized nanodiamonds demonstrated the advantage of active targeting in the presence of cancer cells expressing CD44 on the surface, suggesting higher drug delivery to tumors over non-tumor tissues. Even CD44-poorly expressing cancers could be targeted by the NDs, thanks to their good passive diffusion within cancer cells.

Stability Study of Synthetic Diamond Using a Thermally Controlled Biological Environment: Application towards Long-Lasting Neural Prostheses

This paper demonstrates, for the first time, the stability of synthetic diamond as a passive layer within neural implants. Leveraging the exceptional biocompatibility of intrinsic nanocrystalline diamond, a comprehensive review of material aging analysis in the context of in-vivo implants is provided. This work is based on electric impedance monitoring through the formulation of an analytical model that scrutinizes essential parameters such as the deposited metal resistivity, insulation between conductors, changes in electrode geometry, and leakage currents. The evolution of these parameters takes place over an equivalent period of approximately 10 years. The analytical model, focusing on a fractional capacitor, provides nuanced insights into the surface conductivity variation. A comparative study is performed between a classical polymer material (SU8) and synthetic diamond. Samples subjected to dynamic impedance analysis reveal distinctive patterns over time, characterized by their physical degradation. The results highlight the very high stability of diamond, suggesting promise for the electrode's enduring viability. To support this analysis, microscopic and optical measurements conclude the paper and confirm the high stability of diamond and its strong potential as a material for neural implants with long-life use.

Fluorescent Nanocarbons: From Synthesis and Structure to Cancer Imaging and Therapy

Nanocarbons are emerging at the forefront of nanoscience, with diverse carbon nanoforms emerging over the past two decades. Early cancer diagnosis and therapy, driven by advanced chemistry techniques, play a pivotal role in mitigating mortality rates associated with cancer. Nanocarbons, with an attractive combination of well-defined architectures, biocompatibility, and nanoscale dimension, offer an incredibly versatile platform for cancer imaging and therapy. This paper aims to review the underlying principles regarding the controllable synthesis, fluorescence origins, cellular toxicity, and surface functionalization routes of several classes of nanocarbons: carbon nanodots, nanodiamonds, carbon nanoonions, and carbon nanohorns. This review also highlights recent breakthroughs regarding the green synthesis of different nanocarbons from renewable sources. It also presents a comprehensive and unified overview of the latest cancer-related applications of nanocarbons and how they can be designed to interface with biological systems and work as cancer diagnostics and therapeutic tools. The commercial status for large-scale manufacturing of nanocarbons is also presented. Finally, it proposes future research opportunities aimed at engendering modifiable and high-performance nanocarbons for emerging applications across medical industries. This work is envisioned as a cornerstone to guide interdisciplinary teams in crafting fluorescent nanocarbons with tailored attributes that can revolutionize cancer diagnostics and therapy.

Nanodiamonds: Next generation nano-theranostics for cancer therapy

Cancer remains a leading global cause of mortality, demanding early diagnosis and effective treatment. Traditional therapeutic methods often fall short due to their need for more specificity and systemic toxicity. In this challenging landscape, nanodiamonds (ND) emerge as a potential solution, mitigating the limitations of conventional approaches. ND are tiny carbon particles that mimic traditional diamonds chemical stability and hardness and harness nanomaterials' advantages. ND stands out for the unique properties that make them promising nanotheranostics candidates, combining therapeutic and imaging capabilities in one platform. Many of these applications depend on the design of the particle's surface, as the surface's role is crucial in transporting bioactive molecules, preventing aggregation, and building composite materials. This review delves into ND's distinctive features, structural and optical characteristics, and their profound relevance in advancing cancer diagnosis and treatment methods. The report delves into how these exceptional ND properties drive the development of state-of-the-art techniques for precise tumor targeting, boosting the effectiveness of chemotherapy as a chemosensitizer, harnessing immunotherapy strategies, facilitating precision medicine, and creating localized microfilm devices for targeted therapies.

Fluorescent nanodiamond immunosensors for clinical diagnostics of tuberculosis

Fluorescent nanodiamonds (FNDs) are carbon nanoparticles containing a dense ensemble of nitrogen-vacancy defects as color centers. These centers have exceptional photostability and unique quantum properties, making them useful for ultrasensitive biosensing applications. This work employed FNDs conjugated with antibodies as magneto-optical immunosensors for tuberculosis (TB) diagnostics using competitive spin-enhanced lateral flow immunoassay (SELFIA). ESAT6 (6-kDa early secretory antigenic target) of Mycobacterium tuberculosis is a clinical marker of TB. We evaluated the assay's performance using the recombinant ESAT6 antigen and its antibodies noncovalently coated on FNDs. A detection limit of ∼0.02 ng mL-1 was achieved with the lateral flow membrane strip pre-structured with a narrow channel of 1 mm width. Adopting a cut-off value of 24.0 ng mm-1 for 100-nm FNDs on the strips, the method detected 49 out of 50 clinical samples with Mycobacterium tuberculosis complexes. In contrast, none of the assays for 10 clinical samples with non-tuberculous mycobacteria (NTM) isolates exhibited the presence of ESAT6. These results suggest that the SELFIA platform is applicable for TB detection and can differentiate TB from NTM infections, which also affect the human respiratory system. The FND-enabled immunosensing techniques are versatile and promising for early detection of TB and other diseases, opening a new avenue for biomedical applications of carbon-based nanomaterials.

Comprehensive toxicity assessment of nanodiamond on Blaps polychresta: implications and novel findings

With the increasing development of nanomaterials, the use of nanodiamonds (NDs) has been broadly manifested in many applications. However, their high penetration into the ecosystem indubitably poses remarkable toxicological risks. This paper investigates the toxic effects of NDs on the darkling beetle, Blaps polychresta Forskal, 1775 (Coleoptera: Tenebrionidae). Survival analysis was carried out by monitoring the beetles for 30 d after the injection of four different doses of NDs. A dose of 10.0 mg NDs/g body weight, causing less than 50% mortality effect, was assigned in the analysis of the different organs of studied beetles, including testis, ovary, and midgut. Structural and ultrastructural analyses were followed using light, TEM, and SEM microscopes. In addition, a variety of stress markers and enzyme activities were assessed using spectrophotometric methods. Furthermore, cell viability and DNA damage were evaluated using cytometry and comet assay, respectively. Compared to the control group, the NDs-treated group was exposed to various abnormalities within all the studied organs as follows. Significant disturbances in enzyme activities were accompanied by an apparent dysregulation in the antioxidant system. The flow cytometry results indicated a substantial decrease of viable cells along with a rise of apoptotic and necrotic cells. The comet assay demonstrated a highly increased level of DNA damage. Likewise, histological analyses accentuated the same findings showing remarkable deformities in the studied organs. Prominently, the research findings substantially contribute for the first time to evaluating the critical effects of NDs on B. polychresta, adopted as the bioindicator in this paper.

Nanodiamond Effects on Cancer Cell Radiosensitivity: The Interplay between Their Chemical/Physical Characteristics and the Irradiation Energy

Nanoparticles are being increasingly studied to enhance radiation effects. Among them, nanodiamonds (NDs) are taken into great consideration due to their low toxicity, inertness, chemical stability, and the possibility of surface functionalization. The objective of this study is to explore the influence of the chemical/physical properties of NDs on cellular radiosensitivity to combined treatments with radiation beams of different energies. DAOY, a human radioresistant medulloblastoma cell line was treated with NDs-differing for surface modifications [hydrogenated (H-NDs) and oxidized (OX-NDs)], size, and concentration-and analysed for (i) ND internalization and intracellular localization, (ii) clonogenic survival after combined treatment with different radiation beam energies and (iii) DNA damage and apoptosis, to explore the nature of ND-radiation biological interactions. Results show that chemical/physical characteristics of NDs are crucial in determining cell toxicity, with hydrogenated NDs (H-NDs) decreasing either cellular viability when administered alone, or cell survival when combined with radiation, depending on ND size and concentration, while OX-NDs do not. Also, irradiation at high energy (γ-rays at 1.25 MeV), in combination with H-NDs, is more efficient in eliciting radiosensitisation when compared to irradiation at lower energy (X-rays at 250 kVp). Finally, the molecular mechanisms of ND radiosensitisation was addressed, demonstrating that cell killing is mediated by the induction of Caspase-3-dependent apoptosis that is independent to DNA damage. Identifying the optimal combination of ND characteristics and radiation energy has the potential to offer a promising therapeutic strategy for tackling radioresistant cancers using H-NDs in conjunction with high-energy radiation.

Carboxyl nanodiamonds inhibit melanoma tumor metastases by blocking cellular motility and invasiveness

Carboxyl nanodiamond (cND) nanoparticles are actively internalized by B16F10 melanoma cells in culture. Treatment of B16F10 tumor cells with cNDs in vitro inhibited their ability to (i) migrate and invade through porous membranes in a transwell culture system, (ii) secrete matrix metalloproteinases (MMPs) MMP-2 and MMP-9, and (iii) express selected epithelial-mesenchymal transition markers critical for cell migration and invasion. Administration of luciferase-transfected B16F10-Luc2 melanoma cells resulted in a rapid growth of the tumor and its metastasis to different organs that could be monitored by in vivo bioluminescence imaging as well as by ex vivo BLI of the mouse organs. After tumor cells were administered intravenously in C57Bl/6 mice, administration of cNDs (50 μg i.v. every alternate day) resulted in marked suppression of the tumor growth and metastasis in different organs of mice. Subcutaneous administration of B16F10 cells resulted in robust growth of the primary tumor subcutaneously as well as its metastasis to the lungs, liver, spleen, and kidneys. Intravenous treatment with cNDs did not affect the growth of the primary tumor mass but essentially blocked the metastasis of the tumor to different organs. Histological examination of mouse organs indicated that the administration of cNDs by itself was safe and did not cause toxic changes in mouse organs. These results indicate that the cND treatment may have an antimetastatic effect on the spread of B16F10 melanoma tumor cells in mice. Further exploration of cNDs as a possible antimetastatic therapeutic agent is suggested.

Production, surface modification, physicochemical properties, biocompatibility, and bioimaging applications of nanodiamonds

Nanodiamonds (ND) are chemically inert and stable owing to their sp3 covalent bonding structure, but their surface sp2 graphitic carbons can be easily homogenized with diverse functional groups via oxidation, reduction, hydrogenation, amination, and halogenation. Further surface conjugation of NDs with hydrophilic ligands can boost their colloidal stability and functionality. In addition, NDs are non-toxic as they are made of carbons. They exhibit stable fluorescence without photobleaching. They also possess paramagnetic and ferromagnetic properties, making them suitable for use as a new type of fluorescence imaging (FI) and magnetic resonance imaging (MRI) probe. In this review, we focused on recently developed ND production methods, surface homogenization and functionalization methods, biocompatibilities, and biomedical imaging applications as FI and MRI probes. Finally, we discussed future perspectives.

Recent Progress in Fluorescent Probes for Real-Time Monitoring of Glioblastoma

Treating glioblastoma (GBM) by resecting to a large extent can prolong a patient's survival by controlling the tumor cells, but excessive resection may produce postoperative complications by perturbing the brain structures. Therefore, various imaging procedures have been employed to successfully diagnose and resect with utmost caution and to protect vital structural or functional features. Fluorescence tagging is generally used as an intraoperative imaging technique in glioma cells in collaboration with other surgical tools such as MRI and navigation methods. However, the existing fluorescent probes may have several limitations, including poor selectivity, less photostability, false signals, and intraoperative re-administration when used in clinical and preclinical studies for glioma surgery. The involvement of smart fluorogenic materials, specifically fluorescent dyes, and biomarker-amended cell-penetrable fluorescent probes have noteworthy advantages for precise glioma imaging. This review outlines the contemporary advancements of fluorescent probes for imaging glioma cells along with their challenges and visions, with the anticipation to develop next-generation smart glioblastoma detection modalities.

Correlative Fluorescence and Transmission Electron Microscopy Assisted by 3D Machine Learning Reveals Thin Nanodiamonds Fluoresce Brighter

Nitrogen vacancy (NV) centers in fluorescent nanodiamonds (FNDs) draw widespread attention as quantum sensors due to their room-temperature luminescence, exceptional photo- and chemical stability, and biocompatibility. For bioscience applications, NV centers in FNDs offer high-spatial-resolution capabilities that are unparalleled by other solid-state nanoparticle emitters. On the other hand, pursuits to further improve the optical properties of FNDs have reached a bottleneck, with intense debate in the literature over which of the many factors are most pertinent. Here, we describe how substantial progress can be achieved using a correlative transmission electron microscopy and photoluminescence (TEMPL) method that we have developed. TEMPL enables a precise correlative analysis of the fluorescence brightness, size, and shape of individual FND particles. Augmented with machine learning, TEMPL can be used to analyze a large, statistically meaningful number of particles. Our results reveal that FND fluorescence is strongly dependent on particle shape, specifically, that thin, flake-shaped particles are up to several times brighter and that fluorescence increases with decreasing particle sphericity. Our theoretical analysis shows that these observations are attributable to the constructive interference of light waves within the FNDs. Our findings have significant implications for state-of-the-art sensing applications, and they offer potential avenues for improving the sensitivity and resolution of quantum sensing devices.

Metal-Mediated DNA Adsorption on Carboxylated, Hydroxylated, and Hydrogenated Nanodiamonds

Nanodiamonds (NDs) have attracted considerable attention owing to their quantum properties and versatility in biological applications. In this study, we systematically investigated the adsorption of DNA oligonucleotides onto NDs with three types of surface groups: carboxylated (COOH-), hydroxylated (OH-), and hydrogenated (H-). Among them, only the H-NDs showed fluorescence quenching property that is useful for real-time DNA adsorption kinetic studies. The effect of common metal ions on DNA adsorption was studied. In the presence of Na+, the order of DNA adsorption efficiency was H- > OH- > COOH-, whereas all the NDs showed a similar DNA adsorption efficiency in the presence of divalent metal ions such as Ca2+ and Zn2+. Desorption studies revealed that hydrogen bonding and metal-mediated interactions were dominant for the adsorption of DNA, and the H-NDs exhibited extraordinarily tight DNA adsorption. Finally, a fluorescently labeled DNA was adsorbed on NDs for DNA detection, and the COOH-NDs had the highest target specificity, and a detection limit of 1.4 nM was achieved. This study indicates the feasibility of using metal ions to mediate the physical adsorption of DNA to NDs and compares various NDs with graphene oxide for fundamental understanding.

Mesoporous Polydopamine-Encapsulated Fluorescent Nanodiamonds: A Versatile Platform for Biomedical Applications

Fluorescent nanodiamonds (FNDs) are versatile nanomaterials with promising properties. However, efficient functionalization of FNDs for biomedical applications remains challenging. In this study, we demonstrate mesoporous polydopamine (mPDA) encapsulation of FNDs. The mPDA shell is generated by sequential formation of micelles via self-assembly of Pluronic F127 (F127) with 1,3,5-trimethyl benzene (TMB) and composite micelles via oxidation and self-polymerization of dopamine hydrochloride (DA). The surface of the mPDA shell can be readily functionalized with thiol-terminated methoxy polyethylene glycol (mPEG-SH), hyperbranched polyglycerol (HPG), and d-α-tocopheryl polyethylene glycol 1000 succinate (TPGS). The PEGylated FND@mPDA particles are efficiently taken up by, and employed as a fluorescent imaging probe for, HeLa cells. HPG-functionalized FND@mPDA is conjugated with an amino-terminated oligonucleotide to detect microRNA via hybridization. Finally, the increased surface area of the mPDA shell permits efficient loading of doxorubicin hydrochloride. Further modification with TPGS increases drug delivery efficiency, resulting in high toxicity to cancer cells.

Nano-Diamond-Enhanced Integrated Response of a Surface Plasmon Resonance Biosensor

Surface plasmon resonance (SPR) sensing is a real-time detection technique for measuring biomolecular interactions on gold surfaces. This study presents a novel approach using nano-diamonds (NDs) on a gold nano-slit array to obtain an extraordinary transmission (EOT) spectrum for SPR biosensing. We used anti-bovine serum albumin (anti-BSA) to bind NDs for chemical attachment to a gold nano-slit array. The covalently bound NDs shifted the EOT response depending on their concentration. The number of ND-labeled molecules attached to the gold nano-slit array was quantified from the change in the EOT spectrum. The concentration of anti-BSA in the 35 nm ND solution sample was much lower than that in the anti-BSA-only sample (approximately 1/100). With the help of 35 nm NDs, we were able to use a lower concentration of analyte in this system and obtained better signal responses. The responses of anti-BSA-linked NDs had approximately a 10-fold signal enhancement compared to anti-BSA alone. This approach has the advantage of a simple setup and microscale detection area, which makes it suitable for applications in biochip technology.

Multifunctional Lipophobic Polymer Dots from Cyclodextrin: Antimicrobial/Anticancer Laborers and Silver Ions Chemo-Sensor

β-Cyclodextrin (CD) is currently exploited for the implantation of lipophobic polymer dots (PDs) for antimicrobial and anticancer laborers. Moreover, the PDs were investigated to act as a chemo-sensor for metal detection. The data revealed that under basic conditions, photoluminescent PDs (5.1 nm) were successively clustered with a controllable size at 190 °C, whereas under acidic conditions, smaller-sized non-photoluminescent carbon nanoparticles (2.9 nm) were obtained. The fluorescence intensity of synthesized PDs under basic conditions was affected by pH, and such an intensity was significantly higher compared to that prepared under acidic conditions. The PDs were exploited as florescent detectors in estimation of Ag⁺ ions in aquatic streams. Treatment of Ag⁺ ion colloids with PDs resulted in fluorescence quenching attributing to the production of AgNPs that approved by spectral studies. The cell viability percent was estimated for Escherichia coli, Staphylococcus aureus, and Candida albicans after incubation with PDs implanted under basic conditions for 24 h. The cell mortality percent was estimated for breast cancer (MCF-7) after incubation with different concentrations of PDs that were implanted under acidic versus basic conditions to show that treatment of the tested cells with 1000 μg/mL PDs prepared under basic (IC50 232.5 μg/mL) and acidic (IC₅₀ 88.6 μg/mL) conditions resulted in cell mortality percentages of 70 and 90%, respectively.

Highly Dispersed 3C Silicon Carbide Nanoparticles with a Polydopamine/Polyglycerol Shell for Versatile Functionalization

Silicon carbide (SiC) nanoparticles containing lattice defects are attracting considerable attention as next-generation imaging probes and quantum sensors for visualizing and sensing life activities. However, SiC nanoparticles are not currently used in biomedical applications because of the lack of technology for controlling their physicochemical properties. Therefore, in this study, SiC nanoparticles are deaggregated, surface-coated, functionalized, and selectively labeled to biomolecules of interest. A thermal-oxidation chemical-etching method is developed for deaggregating and producing a high yield of dispersed metal-contaminant-free SiC nanoparticles. We further demonstrated a polydopamine coating with controllable thickness that can be used as a platform for decorating gold nanoparticles on the surface, enabling photothermal application. We also demonstrated a polyglycerol coating, which gives excellent dispersity to SiC nanoparticles. Furthermore, a single-pot method is developed to produce mono/multifunctional polyglycerol-modified SiC nanoparticles. Using this method, CD44 proteins on cell surfaces are selectively labeled through biotin-mediated immunostaining. The methods developed in this study are fundamental for applying SiC nanoparticles to biomedical applications and should considerably accelerate the development of various SiC nanoparticles to exploit their potential applications in bioimaging and biosensing.

Neuronal growth on high-aspect-ratio diamond nanopillar arrays for biosensing applications

Monitoring neuronal activity with simultaneously high spatial and temporal resolution in living cell cultures is crucial to advance understanding of the development and functioning of our brain, and to gain further insights in the origin of brain disorders. While it has been demonstrated that the quantum sensing capabilities of nitrogen-vacancy (NV) centers in diamond allow real time detection of action potentials from large neurons in marine invertebrates, quantum monitoring of mammalian neurons (presenting much smaller dimensions and thus producing much lower signal and requiring higher spatial resolution) has hitherto remained elusive. In this context, diamond nanostructuring can offer the opportunity to boost the diamond platform sensitivity to the required level. However, a comprehensive analysis of the impact of a nanostructured diamond surface on the neuronal viability and growth was lacking. Here, we pattern a single crystal diamond surface with large-scale nanopillar arrays and we successfully demonstrate growth of a network of living and functional primary mouse hippocampal neurons on it. Our study on geometrical parameters reveals preferential growth along the nanopillar grid axes with excellent physical contact between cell membrane and nanopillar apex. Our results suggest that neuron growth can be tailored on diamond nanopillars to realize a nanophotonic quantum sensing platform for wide-field and label-free neuronal activity recording with sub-cellular resolution.

Nanoscale quantum sensing with Nitrogen-Vacancy centers in nanodiamonds - A magnetic resonance perspective

Nanodiamonds containing fluorescent Nitrogen-Vacancy (NV) centers are the smallest single particles, of which a magnetic resonance spectrum can be recorded at room temperature using optically-detected magnetic resonance (ODMR). By recording spectral shift or changes in relaxation rates, various physical and chemical quantities can be measured such as the magnetic field, orientation, temperature, radical concentration, pH or even NMR. This turns NV-nanodiamonds into nanoscale quantum sensors, which can be read out by a sensitive fluorescence microscope equipped with an additional magnetic resonance upgrade. In this review, we introduce the field of ODMR spectroscopy of NV-nanodiamonds and how it can be used to sense different quantities. Thereby we highlight both, the pioneering contributions and the latest results (covered until 2021) with a focus on biological applications.

Bioaccumulation determines the toxicity of carbon dots to two marine dinoflagellates

With the ever-increasing application of carbon dots (CDs), a substantial amount will be released and assemble in the aquatic environment. Nevertheless, potential photodegradation of CDs in the aquatic environment, their accumulation and impacts in aquatic organisms remain unclear. Our study examined the toxicity of CDs to two marine dinoflagellates Prorocentrum micans and Prorocentrum donghaiense. Their bioaccumulation including the uptake and elimination kinetics was also determined. Significant photodegradation of CDs in seawater was observed. Moreover, both the degraded CDs and their photodegradation products were toxic to the dinoflagellates. Although P. donghaiense was more sensitive to CDs than P. micans with the median effect concentration 17.0 and 99.0 mg L^-1, respectively, such sensitivity difference disappeared when the toxicity data were plotted against cellularly accumulated CDs instead of their concentration in the experimental medium. Therefore, the higher sensitivity of P. donghaiense was attributable to its higher accumulation of CDs. Overall, the photodegradation and bioaccumulation of CDs should be considered when evaluating their environmental risks.

Application of Nano-Crystalline Diamond in Tribology

Nano-crystalline diamond has been extensively researched and applied in the fields of tribology, optics, quantum information and biomedicine. In virtue of its hardness, the highest in natural materials, diamond outperforms the other materials in terms of wear resistance. Compared to traditional single-crystalline and poly-crystalline diamonds, nano-crystalline diamond consists of disordered grains and thus possesses good toughness and self-sharpening. These merits render nano-crystalline diamonds to have great potential in tribology. Moreover, the re-nucleation of nano-crystalline diamond during preparation is beneficial to decreasing surface roughness due to its ultrafine grain size. Nano-crystalline diamond coatings can have a friction coefficient as low as single-crystal diamonds. This article briefly introduces the approaches to preparing nano-crystalline diamond materials and summarizes their applications in the field of tribology. Firstly, nano-crystalline diamond powders can be used as additives in both oil- and water-based lubricants to significantly enhance their anti-wear property. Nano-crystalline diamond coatings can also act as self-lubricating films when they are deposited on different substrates, exhibiting excellent performance in friction reduction and wear resistance. In addition, the research works related to the tribological applications of nano-crystalline diamond composites have also been reviewed in this paper.

Clot Imaging Using Photostable Nanodiamond

While thrombosis is the leading cause of morbidity and mortality in the United States, an understanding of its triggers, progression, and response to anticoagulant therapy is lacking. Intravital fluorescence microscopy has advanced the study of thrombus formation by providing targeted, multi-color contrast. However, photodegradation of fluorophores limits the application in longitudinal studies (e.g., clot progression and/or dissolution). Fluorescent nanodiamond (FND) is a fluorophore which utilizes intrinsic fluorescence of chromogenic centers within and protected by the diamond crystalline lattice. Recent developments in diamond processing have allowed for the controlled production of nanodiamonds emitting in green or red. Here, the use of FND to label blood clots and/or clot lysis is demonstrated and compared to commonly used organic fluorophores. Model ex vivo clots were formed with incorporated labeled fibrinogen to allow imaging. FND was shown to match the morphology of organic fluorophore labels absent of photobleaching over time. The addition of tissue plasminogen activator (tPa) allowed visualization of the clot lysis stage, which is vital to studies of both DVT and pulmonary embolism resolution.

Nanodiamond surface as a photoluminescent pH sensor

A systematic spectroscopic characterization of highly homogeneous water suspensions of 'buckydiamonds' comprising sp³cubic nanodiamond (ND) core covered with disordered sp²shell densely decorated with oxygen-containing groups demonstrates the excitation-wavelength-dependent photoluminescence (PL) given by at least four types of specific structures on the ND surface (hydroxyl, C=O containing ketones, carboxylic anhydrides, and carboxyl groups). PL properties of NDs suspensions possess concentration-dependent behavior revealing tendency of NDs to agglomerate. PL of NDs has been found to be strongly sensitive to pH of the environment in wide range of pH values, i.e. 2-11. We disclosed the mechanisms of pH sensitivity of the 'buckydiamond' and proved that it can serve as all-optical sensor of tiny pH variations suitable for further exploitation for pH sensing locally in the area where NDs have been delivered for any purpose, e.g. bioimaging or therapeutic needs.

Quantitative Evaluation of the Cellular Uptake of Nanodiamonds by Monocytes and Macrophages

Fluorescent nanodiamonds (FNDs) with negative nitrogen-vacancy (NV^- ) defect centers are great probes for biosensing applications, with potential to act as biomarkers for cell differentiation. To explore this concept, uptake of FNDs (≈120 nm) by THP-1 monocytes and monocyte-derived M0-macrophages is studied. The time course analysis of FND uptake by monocytes confirms differing FND-cell interactions and a positive time-dependence. No effect on cell viability, proliferation, and differentiation potential into macrophages is observed, while cells saturated with FNDs, unload the FNDs completely by 25 cell divisions and subsequently take up a second dose effectively. FND uptake variations by THP-1 cells at early exposure-times indicate differing phagocytic capability. The cell fraction that exhibits relatively enhanced FND uptake is associated to a macrophage phenotype which derives from spontaneous monocyte differentiation. In accordance, chemical-differentiation of the THP-1 cells into M0-macrophages triggers increased and homogeneous FND uptake, depleting the fraction of cells that were non-responsive to FNDs. These observations imply that FND uptake allows for distinction between the two cell subtypes based on phagocytic capacity. Overall, FNDs demonstrate effective cell labeling of monocytes and macrophages, and are promising candidates for sensing biological processes that involve cell differentiation.

Nanodiamonds Doped with Manganese for Applications in Magnetic Resonance Imaging

Nanodiamonds (NDs) are emerging with great potential in biomedical applications like biomarking through fluorescence and magnetic resonance imaging (MRI), targeted drug delivery, and cancer therapy. The magnetic and optical properties of NDs could be tuned by selective doping. Therefore, we report multifunctional manganese-incorporated NDs (Mn-NDs) fabricated by Mn ion implantation. The fluorescent properties of Mn-NDs were tuned by inducing the defects by ion implantation and enhancing the residual nitrogen vacancy density achieved by a two-step annealing process. The cytotoxicity of Mn-NDs was investigated using NCTC clone 929 cells, and the results revealed no cytotoxicity effect. Mn-NDs have demonstrated dual mode contrast enhancement for both T ₁- and T ₂-weighted in vitro MR imaging. Furthermore, Mn-NDs have illustrated a significant increase in longitudinal relaxivity (fivefold) and transversal relaxivity (17-fold) compared to the as-received NDs. Mn-NDs are employed to investigate their ability for in vivo MR imaging by intraperitoneal (ip) injection of Mn-NDs into mice with liver tumors. After 2.5 h of ip injection, the enhancement of contrast in T ₁- and T ₂-weighted images has been observed via the accumulation of Mn-NDs in liver tumors of mice. Therefore, Mn-NDs have great potential for in vivo imaging by MR imaging in cancer therapy.

Poly(Glycerol)-Based Biomedical Nanodevices Constructed by Functional Programming on Inorganic Nanoparticles for Cancer Nanomedicine

Nanomedicine is promising to improve conventional cancer medicine by making diagnosis and therapy more accurate and more effective in a more personalized manner. A key of the cancer nanomedicine is construction of medical nanodevices by programming various requisite functions to nanoparticles (NPs). As compared to that of soft NPs, including organic micelles and polymers, fabrication of an inorganic NP based nanodevice is still challenging; the approved nanoformulations have been confined to the limited number of superparamagnetic iron oxide NPs (SPIONs). The major challenges lie in how to program the requisite functions to inorganic NPs. In spite the much denser and less hydrophilic properties of inorganic NPs, most of the following functions have to be programmed for their in vivo applications: (A) high dispersibility in a physiological environment, (B) high stealth efficiency to slip through the trap by liver and spleen, (C) high targeting efficiency to cancer tissue, (D) clear visualization of cancer for diagnosis, and (E) high anticancer activity for treatment.In our approach, poly(glycerol) (PG), containing a hydroxy group at every monomer unit, was found as a better alternative to poly(ethylene glycol) (PEG), the most commonly used hydrophilic polymer, giving (A) high dispersibility to inorganic NPs. Although most of the inorganic NPs are not dense in functional groups, the hyperbranched structure with many hydroxy groups in PG turns the less functional surface into highly functional one, imparting not only good hydrophilicity but also (B) high stealth efficiency as we reported recently. In addition, a number of hydroxy groups in PG afford the structural or functional extensibility to introduce the additional layer or function. This enables us to design and construct a three-layer architecture consisting of a core inorganic NP, a hydrophilic and stealthy PG layer, and a functional molecule layer, where their interfaces are connected firmly by covalent bonds. The three-layered nanodevice is very flexible in its design for the following reasons: The PG coating can be applied to a wide variety of inorganic NPs with various functions, and various functional moieties can be introduced on the PG layer as a functional molecule layer. Owing to the versatility of the three-layer model, the rest of the above functions (C)-(E) can be programed in the NP core and/or the outmost layer in nanodevices.In this Account, the author described first the methodology for precise construction and quantitative characterization of various biomedical nanodevices. This fundamental aspect of this research has been achieved by "applying organic chemistry to nanomaterials" which is the concept of our research. That is, the rich chemistry in synthesis and characterization of organic compounds has been applied to the nanodevice fabrication and characterization. Second, evaluation of the functions programmed in the nanodevices is described in terms of stealth and targeting efficiencies, cancer diagnosis and therapy, and biomedical sensing. This stage in our research made us more interdisciplinary from chemistry and nanoscience to biology and medicine. The following research spiral has been established in our group to strongly promote the improvement of our biomedical nanodevices; nanodevice design → precise construction → quantitative characterization → functional evaluation.

Green Synthesis of Carbon Nanoparticles (CNPs) from Biomass for Biomedical Applications

In this review, we summarize recent work on the "green synthesis" of carbon nanoparticles (CNPs) and their application with a focus on biomedical applications. Recent developments in the green synthesis of carbon nanoparticles, from renewable precursors and their application for environmental, energy-storage and medicinal applications are discussed. CNPs, especially carbon nanotubes (CNTs), carbon quantum dots (CQDs) and graphene, have demonstrated utility as high-density energy storage media, environmental remediation materials and in biomedical applications. Conventional fabrication of CNPs can entail the use of toxic catalysts; therefore, we discuss low-toxicity manufacturing as well as sustainable and environmentally friendly methodology with a focus on utilizing readily available biomass as the precursor for generating CNPs.

Evaluation of Cytotoxicity and Bioimaging of Nitrogen-Vacancy Nanodiamonds

Nanodiamonds, due to their chemical inertness and biocompatibility, have found extensive uses in drug delivery and biomedical applications. Fluorescent nanodiamonds with fluorescent properties generated by nitrogen-vacancy defects have been intensively investigated for bioimaging, due to their high quantum yield and high photobleaching stability. In addition, the surface properties and particle size of nanodiamonds have significant impacts on cellular uptake and imaging quality. In this study, nitrogen-vacancy nanodiamonds with different particle sizes (40 nm and 90 nm) have been physicochemically characterised and investigated for their cytotoxicity and potential in fluorescence imaging. The nanodiamonds (with concentrations up to 100 µg/mL) showed cell viability >70% with mesenchymal stromal cells. The number of nanodiamonds was observed to have a larger impact on cell viability than the mass of nanodiamonds. Larger nanodiamonds (90 nm) exhibited a lower level of cytotoxicity, higher cellular uptake and fluorescence intensity. The results indicate the potential of using fluorescent nanodiamonds as a nanoprobe for effective bioimaging and cell tracking.

Microgels based on 0D-3D carbon materials: Synthetic techniques, properties, applications, and challenges

Microgels are three-dimensional (3D) colloidal hydrogel particles with outstanding features such as biocompatibility, good mechanical properties, tunable sizes from submicrometer to tens of nanometers, and large surface areas. Because of these unique qualities, microgels have been widely used in various applications. Carbon-based materials (CMs) with various dimensions (0-3D) have recently been investigated as promising candidates for the design and fabrication of microgels because of their large surface area, excellent conductivity, unique chemical stability, and low cost. Here, we provide a critical review of the specific characteristics of CMs that are being incorporated into microgels, as well as the state-of-the art applications of CM-microgels in pollutant adsorption and photodegradation, H₂ evoluation, CO₂ capture, soil conditioners, water retention, drug delivery, cell encapsulation, and tissue engineering. Advanced preparation techniques for CM-microgel systems are also summarized and discussed. Finally, challenges related to the low colloidal stability of CM-microgels and development strategies are examined. This review shows that CM-microgels have the potential to be widely used in various practical applications.

All-Optical Modulation of Single Defects in Nanodiamonds: Revealing Rotational and Translational Motions in Cell Traction Force Fields

Measuring the mechanical interplay between cells and their surrounding microenvironment is vital in cell biology and disease diagnosis. Most current methods can only capture the translational motion of fiduciary markers in the deformed matrix, but their rotational motions are normally ignored. Here, by utilizing single nitrogen-vacancy (NV) centers in nanodiamonds (NDs) as fluorescent markers, we propose a linear polarization modulation (LPM) method to monitor in-plane rotational and translational motions of the substrate caused by cell traction forces. Specifically, precise orientation measurement and localization with background suppression were achieved via optical polarization selective excitation of single NV centers with precisions of ∼0.5°/7.5 s and 2 nm/min, respectively. Additionally, we successfully applied this method to monitor the multidimensional movements of NDs attached to the vicinity of cell focal adhesions. The experimental results agreed well with our theoretical calculations, demonstrating the practicability of the NV-based LPM method in studying mechanobiology and cell-material interactions.

Use of Magnetic Modulation of Nitrogen-Vacancy Center Fluorescence in Nanodiamonds for Quantitative Analysis of Nanoparticles in Organisms

The fluorescence intensity emitted by nitrogen-vacancy (NV) centers in diamond nanoparticles can be readily modulated by the application of a magnetic field using a small electromagnet. By acquiring interleaved images acquired in the presence and absence of the magnetic field and performing digital subtraction, the fluorescence intensity of the NV nanodiamond can be isolated from scattering and autofluorescence even when these backgrounds are changing monotonically during the experiments. This approach has the potential to enable the robust identification of nanodiamonds in organisms and other complex environments. Yet, the practical application of magnetic modulation imaging to realistic systems requires the use of quantitative analysis methods based on signal-to-noise considerations. Here, we describe the use of magnetic modulation to analyze the uptake of diamond nanoparticles from an aqueous environment into Caenorhabditis elegans, used here as a model system for identification and quantification of nanodiamonds in complex matrices. Based on the observed signal-to-noise ratio of sets of digitally subtracted images, we show that nanodiamonds can be identified on an individual pixel basis with a >99.95% confidence. To determine whether surface functionalization of the nanodiamond significantly impacted uptake, we used this approach to analyze the presence of nanodiamonds in C. elegans that had been exposed to these functionalized nanodiamonds in the water column, with uptake likely occurring by ingestion. In each case, the images show a significant nanoparticle uptake. However, differences in uptake between the three ligands were not outside of the experimental error, indicating that additional factors beyond the surface charge are important factors controlling uptake. Analysis of the number of pixels above the threshold in individual C. elegans organisms revealed distributions that deviate significantly from a Poisson distribution, suggesting that uptake of nanoparticles may not be a statistically independent event. The results presented here demonstrate that magnetic modulation combined with quantitative analysis of the resulting images can be used to robustly characterize nanoparticle uptake into organisms.

Fluorescent Nanoparticles for Super-Resolution Imaging

Super-resolution imaging techniques that overcome the diffraction limit of light have gained wide popularity for visualizing cellular structures with nanometric resolution. Following the pace of hardware developments, the availability of new fluorescent probes with superior properties is becoming ever more important. In this context, fluorescent nanoparticles (NPs) have attracted increasing attention as bright and photostable probes that address many shortcomings of traditional fluorescent probes. The use of NPs for super-resolution imaging is a recent development and this provides the focus for the current review. We give an overview of different super-resolution methods and discuss their demands on the properties of fluorescent NPs. We then review in detail the features, strengths, and weaknesses of each NP class to support these applications and provide examples from their utilization in various biological systems. Moreover, we provide an outlook on the future of the field and opportunities in material science for the development of probes for multiplexed subcellular imaging with nanometric resolution.

Nanodiamonds as Possible Tools for Improved Management of Bladder Cancer and Bacterial Cystitis

Nanodiamonds (NDs) are a class of carbon nanomaterials with sizes ranging from a few nm to micrometres. Due to their excellent physical, chemical and optical properties, they have recently attracted much attention in biomedicine. In addition, their exceptional biocompatibility and the possibility of precise surface functionalisation offer promising opportunities for biological applications such as cell labelling and imaging, as well as targeted drug delivery. However, using NDs for selective targeting of desired biomolecules within a complex biological system remains challenging. Urinary bladder cancer and bacterial cystitis are major diseases of the bladder with high incidence and poor treatment options. In this review, we present: (i) the synthesis, properties and functionalisation of NDs; (ii) recent advances in the study of various NDs used for better treatment of bladder cancer and (iii) bacterial cystitis; and (iv) the use of NDs in theranostics of these diseases.

Construction of a photo-controlled fluorescent switching with diarylethene modified carbon dots

Photo-controlled fluorescent switching is of great utility in fluorescence sensors, reversible data storage, and logic circuit, based on their modifiable emission intensity and spectra. In this work, a novel photo-controlled reversible fluorescent switching system was constructed based on photochromic diarylethene (DT) molecular modified fluorescent carbon dots (CDs). The fluorescent CDs acted as fluorescent donors and the photochromic diarylethene molecular functioned as acceptors in this fluorescent switching system. The fluorescence modulation efficiency of the fluorescent switching was determined to be 97.1%. The result was attributable to Förster resonance energy transfer between the CDs and the diarylethene molecular. The fluorescent switching could undergo 20 cycles without significant decay.

Recent Developments of Nanodiamond Quantum Sensors for Biological Applications

Measuring certain quantities at the nanoscale is often limited to strict conditions such as low temperature or vacuum. However, the recently developed nanodiamond (ND) quantum sensing technology shows great promise for ultrasensitive diagnosis and probing subcellular parameters at ambient conditions. Atom defects (i.e., N, Si) within the ND lattice provide stable emissions and sometimes spin-dependent photoluminescence. These unique properties endow ND quantum sensors with the capacity to detect local temperature, magnetic fields, electric fields, or strain. In this review, some of the recent, most exciting developments in the preparation and application of ND sensors to solve current challenges in biology and medicine including ultrasensitive detection of virions and local sensing of pH, radical species, magnetic fields, temperature, and rotational movements, are discussed.

Recent Advances in Inflammatory Diagnosis with Graphene Quantum Dots Enhanced SERS Detection

Inflammatory diseases are some of the most common diseases in different parts of the world. So far, most attention has been paid to the role of environmental factors in the inflammatory process. The diagnosis of inflammatory changes is an important goal for the timely diagnosis and treatment of various metastatic, autoimmune, and infectious diseases. Graphene quantum dots (GQDs) can be used for the diagnosis of inflammation due to their excellent properties, such as high biocompatibility, low toxicity, high stability, and specific surface area. Additionally, surface-enhanced Raman spectroscopy (SERS) allows the very sensitive structural detection of analytes at low concentrations by amplifying electromagnetic fields generated by the excitation of localized surface plasmons. In recent years, the use of graphene quantum dots amplified by SERS has increased for the diagnosis of inflammation. The known advantages of graphene quantum dots SERS include non-destructive analysis methods, sensitivity and specificity, and the generation of narrow spectral bands characteristic of the molecular components present, which have led to their increased application. In this article, we review recent advances in the diagnosis of inflammation using graphene quantum dots and their improved detection of SERS. In this review study, the graphene quantum dots synthesis method, bioactivation method, inflammatory biomarkers, plasma synthesis of GQDs and SERS GQD are investigated. Finally, the detection mechanisms of SERS and the detection of inflammation are presented.

Applications of Fluorescent Nanodiamond in Biology

Fluorescent nanodiamond (FND) has emerged as a promising material in several multidisciplinary areas, including biology, chemistry, physics, and materials science. Composed of sp 3 ‐carbon atoms, FND offers superior biocompatibility, chemical inertness, a large surface area, tunable surface structure, and excellent mechanical characteristics. The nanoparticle is unique in that it comprises a high‐density ensemble of negatively charged nitrogen‐vacancy (NV − ) centers that act as built‐in fluorophores and exhibit a number of remarkable optical and magnetic properties. These properties make FND particularly well suited for a wide range of applications, including cell labeling, long‐term cell tracking, super‐resolution imaging, nanoscale sensing, and drug delivery. This article discusses recent applications of FND‐enabled developments in biology.

Improving Thermal and Photostability of Polymer Solar Cells by Robust Interface Engineering

As the power conversion efficiency (PCE) of organic photovoltaics (OPVs) approaches 19%, increasing research attention is being paid to enhancing the device's long-term stability. In this study, a robust interface engineering of graphene oxide nanosheets (GNS) is expounded on improving the thermal and photostability of non-fullerene bulk-heterojunction (NFA BHJ) OPVs to a practical level. Three distinct GNSs (GNS, N-doped GNS (N-GNS), and N,S-doped GNS (NS-GNS)) synthesized through a pyrolysis method are applied as the ZnO modifier in inverted OPVs. The results reveal that the GNS modification introduces passivation and dipole effects to enable better energy-level alignment and to facilitate charge transfer across the ZnO/BHJ interface. Besides, it optimizes the BHJ morphology of the photoactive layer, and the N,S doping of GNS further enhances the interaction with the photoactive components to enable a more idea BHJ morphology. Consequently, the NS-GNS device delivers enhanced performance from 14.5% (control device) to 16.5%. Moreover, the thermally/chemically stable GNS is shown to stabilize the morphology of the ZnO electron transport layer (ETL) and to endow the BHJ morphology of the photoactive layer grown atop with a more stable thermodynamic property. This largely reduces the microstructure changes and the associated charge recombination in the BHJ layer under constant thermal/light stresses. Finally, the NS-GNS device is demonstrated to exhibit an impressive T₈₀ lifetime (time at which PCE of the device decays to 80% of the initial PCE) of 2712 h under a constant thermal condition at 65 °C in a glovebox and an outstanding photostability with a T₈₀ lifetime of 2000 h under constant AM1.5G 1-sun illumination in an N₂ -controlled environment.

Silicon-Vacancy Nanodiamonds as High Performance Near-Infrared Emitters for Live-Cell Dual-Color Imaging and Thermometry

Nanodiamonds (NDs) with color centers are excellent emitters for various bioimaging and quantum biosensing applications. In our work, we explore new applications of NDs with silicon-vacancy centers (SiV) obtained by high-pressure high-temperature (HPHT) synthesis based on metal-catalyst-free growth. They are coated with a polypeptide biopolymer, which is essential for efficient cellular uptake. The unique optical properties of NDs with SiV are their high photostability and narrow emission in the near-infrared region. Our results demonstrate for the first time that NDs with SiV allow live-cell dual-color imaging and intracellular tracking. Also, intracellular thermometry and challenges associated with SiV atomic defects in NDs are investigated and discussed for the first time. NDs with SiV nanoemitters provide new avenues for live-cell bioimaging, diagnostic (SiV as a nanosized thermometer), and theranostic (nanodiamonds as drug carrier) applications.