Biodegradable rare earth fluorochloride nanocrystals for phototheranostics

Ecotoxicity of non- and PEG-modified lanthanide-doped nanoparticles in aquatic organisms

Various types of nanoparticles (NPs) have been widely investigated recently and applied in areas such as industry, the energy sector, and medicine, presenting the risk of their release into the environment. The ecotoxicity of NPs depends on several factors such as their shape and surface chemistry. Polyethylene glycol (PEG) is one of the most often used compounds for functionalisation of NP surfaces, and its presence on the surfaces of NPs may affect their ecotoxicity. Therefore, the present study aimed to assess the influence of PEG modification on the toxicity of NPs. As biological model, we chose freshwater microalgae, a macrophyte and invertebrates, which to a considerable extent enable the assessment of the harmfulness of NPs to freshwater biota. SrF₂:Yb³⁺,Er³⁺ NPs were used to represent the broad group of up-converting NPs, which have been intensively investigated for medical applications. We quantified the effects of the NPs on five freshwater species representing three trophic levels: the green microalgae Raphidocelis subcapitata and Chlorella vulgaris, the macrophyte Lemna minor, the cladoceran Daphnia magna and the cnidarian Hydra viridissima. Overall, H. viridissima was the most sensitive species to NPs, which affected its survival and feeding rate. In this case, PEG-modified NPs were slightly more toxic than bare ones (non-significant results). No effects were observed on the other species exposed to the two NPs at the tested concentrations. The tested NPs were successfully imaged in the body of D. magna using confocal microscopy; both NPs were detected in the D. magna gut. The results obtained reveal that SrF₂:Yb³⁺,Er³⁺ NPs can be toxic to some aquatic species; however, the structures have low toxicity effects for most of the tested species.

A multi-responsive targeting drug delivery system for combination photothermal/chemotherapy of tumor

To achieve efficient delivery and precise release of chemotherapy drugs at tumor sites, an active targeting multi-responsive drug delivery platform was developed. Here, doxorubicin hydrochloride (DOX) was loaded onto polydopamine (PDA), which were coated by the cystamine-modified hyaluronic acid (HA-Cys), designated as DOX@PDA-HA (PDH). The combination of PDA and HA-Cys endowed the nanoplatform photothermal conversion, tumor-targeting, and pH/redox/NIR sensitive drug release capacity. Moreover, HA could be degraded by the excess hyaluronidase (HAase) in the tumor microenvironment (TME), promoting DOX release, and further enhancing the effect of chemotherapy. Experimental results demonstrated PDH good biocompatibility, high loading rate, targeted drug delivery, and efficient tumor cell killing ability. This ingenious strategy based on PDH showed huge potential in photothermal/chemotherapy combination treatment of cancer.

Effect of the Amount of Carbon in the Fe3O4@ZnO-C Nanocomposites on Its Structure and Magnetic Properties

Synthesis and characterization of structure magnetic properties of Fe3O4@ZnO- C nanocomposite have been done through the precipitation method. This study aimed to discover the effect of concentrations/thickness of carbon layer on crystal structure and magnetic properties of Fe3O4@ZnO-C nanocomposites. Fe3O4 and Fe3O4@ZnO were the samples used in the study, and variations in the amount of carbon were 0.2, 0.1, and 0.05 g. Nanocomposites were characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and vibrating sample magnetometer (VSM). Based on the results of XRD, it has been found that the crystal structure for Fe3O4 was cubic, while ZnO was hexagonal wurtzite. The addition of carbons to Fe3O4@ZnO caused a broadening of the diffraction peaks and a decrease in the degree of crystallinity. The bonds formed on Fe3O4@ZnO-C nanocomposites, i.e. Fe-O bonds indicated the formation of Fe3O4, Zn-O bonds showed the formation of ZnO and C-O, C-H, and O-H bonds revealed the presence of a carbon layer originated from glucose. The VSM results showed that the magnetic saturation decreased with increasing carbon mass. Overall, the carbon-coated nanocomposite material with a carbon mass variation of 0.2, 0.1, and 0.05 g showed superparamagnetic properties with a magnetic saturation of 18.23 emu/g, 19.33 emu/g and 22.05 emu/g, while for the coercive field of 92.29 Oe, 92.90 Oe and 89.60 Oe, respectively. Based on these characterization results, Fe3O4@ZnO-C nanocomposite materials can potentially be developed as biomedical materials, such as the materials for photothermal therapy for cancer cells.

Local atomic environment of Yb3+ in alkaline-earth fluorohalide nanocrystals

The local atomic environment of Yb3+ ions doped into alkaline-earth fluorohalide nanocrystals was probed using Yb L2 edge EXAFS spectroscopy. Two structural models are proposed for the first coordination shell of Yb3+.

Nano-Bio-engineered Silk Matrix based Devices for Molecular Bioanalysis

Silk is a fibrous protein, has been a part of human lives for centuries and was used as suture and textile material. Silk is mainly produced by members of certain arthropods such as spiders, butterflies, mites, and moths. However, recent technological advances have revolutionized silk as a biomaterial for various applications ranging from heat sensors to robust fibers. The biocompatibility, mechanical resilience, and biodegradability of the material make it a suitable candidate for biomaterials. Silk can also be easily converted into several morphological forms, including fibers, films, sponges, and hydrogels. Provided these abilities, silk have received excellent traction from scientists worldwide for various developments, one of them being its use as a bio-sensor. The diversity of silk materials offers various options, giving scientists the freedom to choose from and personalize them as per their needs. In this review, we foremost look upon the composition, production, properties, and various morphologies of silk. The numerous applications of silk and its derivatives for fabricating biosensors to detect small molecules, macromolecules, and cells have been explored comprehensively. Also, the data from various globally developed sensors using silk have been described into organized tables for each category of molecules, along with their important analytical details. This article is protected by copyright. All rights reserved.