Quantitatively imaging the spatiotemporal distribution of biological events in living organisms is essential to understand fundamental biological processes. Self-calibrating ratiometric fluorescent probes enable accurate and reliable imaging and sensing, but conventional probes using wavelength of 400–900 nm suffer from extremely low resolution for in vivo application due to the disastrous photon scattering and tissue autofluorescence background. Here, we develop a NIR-IIb (1500–1700 nm) emissive nanoprobe for high-resolution ratiometric fluorescence imaging in vivo. The obtained nanoprobe shows fast ratiometric response to hypochlorous acid (HOCl) with a detection limit down to 500 nM, through an absorption competition-induced emission (ACIE) bioimaging system between lanthanide-based downconversion nanoparticles and Cy7.5 fluorophores. Additionally, we demonstrate the superior spatial resolution of 1550 nm to a penetration depth of 3.5 mm in a scattering tissue phantom, which is 7.1-fold and 2.1-fold higher than that of 1064 and 1344 nm, respectively. With this nanoprobe, clear anatomical structures of lymphatic inflammation in ratiometric channel are observed with a precise resolution of ∼477 μm. This study will motivate the further research on the development of NIR-II probes for high-resolution biosensing in vivo.

With the evolution of nanoscience and nanotechnology, studies have been focused on manipulating nanoparticle properties through the control of their size, composition, and morphology. As nanomaterial research has progressed, the foremost focus has gradually shifted from synthesis, morphology control, and characterization of properties to the investigation of function and the utility of integrating these materials and chemical sciences with the physical, biological, and medical fields, which therefore necessitates the development of novel materials that are capable of performing multiple tasks and functions. The construction of multifunctional nanomaterials that integrate two or more functions into a single geometry has been achieved through the surface-coating technique, which created a new class of substances designated as core-shell nanoparticles. Core-shell materials have growing and expanding applications due to the multifunctionality that is achieved through the formation of multiple shells as well as the manipulation of core/shell materials. Moreover, core removal from core-shell-based structures offers excellent opportunities to construct multifunctional hollow core architectures that possess huge storage capacities, low densities, and tunable optical properties. Furthermore, the fabrication of nanomaterials that have the combined properties of a core-shell structure with that of a hollow one has resulted in the creation of a new and important class of substances, known as the rattle core-shell nanoparticles, or nanorattles. The design strategies of these new multifunctional nanostructures (core-shell, hollow core, and nanorattle) are discussed in the first part of this review. In the second part, different synthesis and fabrication approaches for multifunctional core-shell, hollow core-shell and rattle core-shell architectures are highlighted. Finally, in the last part of the article, the versatile and diverse applications of these nanoarchitectures in catalysis, energy storage, sensing, and biomedicine are presented.

Drug-induced hepatotoxicity represents an important challenge for safety in drug development. The production of peroxynitrite (ONOO–) is proposed as an early sign in the progression of drug-induced hepatotoxicity. Currently, reported ONOO– probes mainly emit in the visible range or the first NIR window, which have limited in vivo biosensing application due to the autofluorescence and photon scattering. Herein, we developed a peroxynitrite activatable second near-infrared window (NIR-II) molecular probe for drug-induced hepatotoxicity monitoring, based on the fusion of an NIR-II fluorescence turn-on benzothiopyrylium cyanines skeleton and the phenyl borate. In the presence of ONOO–, the probe IRBTP-B can turn on its NIR-II fluorescence by yielding its fluorophore IRBTP-O and display good linear response to ONOO–. Tissue phantom study confirmed reliable activated signals could be acquired at a penetration depth up to 5 mm. Using this probe, we disclose the upregulation of ONOO– in a preclinical drug-induced liver injury model and the remediation with N-acetyl cysteine (NAC) in vivo. We expect that this strategy will serve as a general method for the development of an activatable NIR-II probe based on the hydroxyl functionalized reactive sites by analyte-specific triggering.

In the present study, graphene oxide (GO) was incorporated as a nanoadditive into a polyphenylsulfone (PPSU) to develop a PPSU/GO nanocomposite membrane with enhanced antifouling properties. A series of membranes containing different concentrations (0.2, 0.5 and 1.0 wt.%) of GO were fabricated via the phase inversion method, using N-methyl pyrrolidone (NMP) as the solvent, deionized water as the non-solvent, and polyvinylpyrrolidone (PVP) as a pore forming agent. The prepared nanocomposite membranes were characterized using scanning electron microscopy (SEM) and atomic force microscopy (AFM), and were also characterized with respect to contact angle, zeta potential and porosity, mean pore radius, tortuosity and molecular weight cut-off (MWCO). Thermogravimetric analysis (TGA) and tensile testing were used to measure thermal and mechanical properties. The membrane performance was evaluated by volumetric flux and rejection of proteins, and antifouling properties. According to the results, the optimum addition of 0.5 wt% GO resulted in a membrane with an increased flux of 171 ± 3 Lm−2h−1 with a MWCO of ~40 kDa. In addition, the GO incorporation efficiently inhibited the interaction between proteins and the membrane surface, thereby improving the fouling resistance ability by approximately 58 ± 3%. Also, the resulting membranes showed a significant improvement in mechanical and thermal properties.

Lanthanide doped core/shell structured nanoparticles have being widely studied because of their unique optical properties and promising applications in many fields. However, the elemental migration of the lanthanide ions in the core/shell nanoparticles still lacks sufficient understanding, which may influence the optical properties of the nanoparticles. By monitoring of the variation of optical properties during the postannealing progress in the solution at high temperature, the elemental migration of Er 3+ in the core/ shell structured NaErF 4 @NaYF 4 luminescent nanoparticles is investigated, which are influenced by the annealing temperature, relative ion radius of lanthanide elements, and doping concentration differential between two adjacent layers. Based on the dopants migration in the core/shell structured nanoparticles, the emission profile of the luminescent nanoparticles can be well tuned by the postannealing process. The findings described here suggest a general insight into constructing lanthanide doped core/shell luminescent nanomaterials with controllable dopant ions spatial distributions and energy migration in the core/shell nanostructure.

Over the past few years, significant efforts have been made to create new fluorescent probes operating at longer wavelengths, particularly in the second near-infrared (NIR-II) window from 1000 to 1700 nm, offering enhanced tissue penetration compared to light in the visible and first near-infrared window (700-900 nm). However, most of the reported NIR-II fluorophores meet such dilemmas; they are excreted slowly and largely retained within the reticuloendothelial system. Here, we report a rapidly excreted NIR-II lanthanide complex Nd-DOTA (over 50% excreted through the kidneys within 3 h postinjection) with a molecular mass only 0.54 kDa. The NIR-II imaging quality of Nd-DOTA was far superior to that of clinically approved ICG with good photostability and deep tissue penetration (7 mm). Superior tumor-to-normal tissue ratio was successfully achieved to facilitate the abdominal ovarian metastases surgical delineation. Metastases with ≤1 mm can be completely excised under NIR-II bioimaging guidance. Significantly, since the Nd-DOTA structure is same to the clinically approved magnetic resonance imaging (MRI) contrast Gd-DOTA, it will speed up the clinical translation for this novel kind of NIR-II probes in the future.

The objective of the present work was to investigate the efficacy of indigenously developed polyacrylonitrile (PAN) based ultrafiltration (UF) membrane for chromium ions removal from potable water. The hydrolyzed PAN membranes effectively rejected chromium anions in the feed ranging from 250 ppb to 400 ppm and a rejection of ≥90% was achieved for pH ≥ 7 at low chromate concentration (≤25 ppm) in feed. The rejection mechanism of chromium ions was strongly dependent on Donnan exclusion principle, while size exclusion principle for UF did not play a major role on ions rejection. Feed pH played a vital role in changing porosity of membrane, which influenced the retention behavior of chromate ions. Cross-flow velocity, pressure did not play significant role for ions rejection at low feed concentration. However, at higher feed concentration (≥400 ppm), concentration polarization became important and it reduced the chromate rejection to 32% at low cross flow and high pressure. Donnan steric-partitioning pore and dielectric exclusion model (DSPM-DE) was applied to evaluate the chromate ions transport through PAN UF membrane as a function of flux by using optimized model parameters and the simulated data matched well with experimental results.

Extended and oriented nanostructures are desirable for many applications, but direct fabrication of complex nanostructures with well-aligned morphology, orientation, and surface architectures remains a significant challenge. Here, we study a simple electrochemical anodizing process to fabricate arrays of titanium ͑Ti͒ nanotubes without the use of a template. The nanotubes are formed perpendicular to the metal substrate as an open-ended array in a continuous, well-aligned conformation. The hole size and separation have been found to be dependent on the anodizing voltage and on anodizing time. It was found that the nanotube deposition process had a low faradaic efficiency, and a large fraction of the Ti was transformed into soluble species in the anodizing bath. The TiO 2 nanotubes have uniform diameters that make them suitable for electrochemical intercalation hosts for Li + ions and other applications.Nanoscale one-dimensional materials, such as nanowires, nanorods, nanofibers, and nanotubes, have attracted interest recently due to their importance in basic scientific research and potential technology applications. 1-3 Specifically, many important metal oxides with nonlayered structure such as TiO 2 , ZnO, MnO 2 , ZrO 2 , and Co 3 O 4 have attracted attention in the fabrication of nanotube structures, despite the high rigidity of the crystal structure. Most of the important progress includes fabrication of the metal oxide nanotubes from anodic aluminum oxide templates ͑AAO͒ and supramolecular templates with various sol-gel methods that transfer materials onto inner or outer surfaces of templates. A recent example of this procedure is the work of Hoyer 4 on TiO 2 nanotubes.The study of TiO 2 films formed on the parent metal has an extensive literature because they provide excellent corrosion protection. However, precursor sites for pitting corrosion 5-7 were discovered in our laboratory recently. The oxide films formed on Ti in sulfuric and hydrochloric acids, and on a wide range of other electrolytes, are normally fully dense, and nanotube structures are completely absent.Several research groups have studied oxide nanotubes, including TiO 2 ͑TONT͒. In the context of the present paper, Zwilling et al. 8 have anodically grown highly porous oxide layers on pure Ti and Ti-6A1-4V alloy in hydrofluoric acid ͑HF͒ solution with or without acetic acid and chromic acid additions. Another group has discussed the morphology of well-aligned nanotube Ti oxide structures fabricated by anodizing and has described details of preparation and modification by heat treatment to form suitable materials for hydrogen sensing systems. 9-14 Schmuki and co-workers 15-17 have explored the effect of solution pH on the size and shape of the TONT formed by anodization. Especially noteworthy is the length of nanotubes formed in near-neutral pH solutions of fluoride. 17 In recent work, Sklar et al. 18 reported a variety of solution compositions that were used for anodic formation of TONT. In a recent paper from our laboratory, ZrO 2 nanotube arr...