A Cancer Nanovaccine Based on an FeAl-Layered Double Hydroxide Framework for Reactive Oxygen Species-Augmented Metalloimmunotherapy

The complexity and heterogeneity of individual tumors have hindered the efficacy of existing therapeutic cancer vaccines, sparking intensive interest in the development of more effective in situ vaccines. Herein, we introduce a cancer nanovaccine for reactive oxygen species-augmented metalloimmunotherapy in which FeAl-layered double hydroxide (LDH) is used as a delivery vehicle with dihydroartemisinin (DHA) as cargo. The LDH framework is acid-labile and can be degraded in the tumor microenvironment, releasing iron ions, aluminum ions, and DHA. The iron ions contribute to aggravated intratumoral oxidative stress injury by the synergistic Fenton reaction and DHA activation, causing apoptosis, ferroptosis, and immunogenic cell death in cancer cells. The subsequently released tumor-associated antigens with the aluminum adjuvant form a cancer nanovaccine to generate robust and long-term immune responses against cancer recurrence and metastasis. Moreover, Fe ion-enabled T1-weighted magnetic resonance imaging can facilitate real-time tumor therapy monitoring. This cancer-nanovaccine-mediated metalloimmunotherapy strategy has the potential for revolutionizing the precision immunotherapy landscape.

Multicolor luminescent material based on interaction between TiNbO5- nanosheets and lanthanide ions for visualization of pH change in inorganic gel electrolyte

Layered nanosheet materials showing a drastic luminescence change in response to changes in proton concentration (pH) were prepared by sandwiching Eu³⁺ and Tb³⁺ cations with anionic TiNbO₅^- nanosheets using electrostatic interaction. Each trivalent lanthanide ion showed a different response to pH change: a strong red emission from Eu³⁺ was observed at low proton concentrations (pH: 13) and a green emission from Tb³⁺ was dominant at high proton concentrations (pH: 1). The photoluminescence intensity was determined by the balance between the photocatalytic activity of TiNbO₅^- nanosheets and energy transfer from the host layer to the guest lanthanide ions. Moreover, the trivalent lanthanide/TiNbO₅^- nanosheet hybrid formed a gel-like solid in aqueous solution, which functioned as an inorganic gel electrolyte when mixed with Na₂SO₄. The multicolor luminescence (red-yellow-green) of the lanthanide/TiNbO₅^- nanosheet hybrid enabled direct visualization of the diffusion of protons in an inorganic gel electrolyte during water electrolysis.

Polymeric Dendrimers as Nanocarrier Vectors for Neurotheranostics

Dendrimers are polymers with well-defined 3D branched structures that are vastly utilized in various neurotheranostics and biomedical applications, particularly as nanocarrier vectors. Imaging agents can be loaded into dendrimers to improve the accuracy of diagnostic imaging processes. Likewise, combining pharmaceutical agents and anticancer drugs with dendrimers can enhance their solubility, biocompatibility, and efficiency. Practically, by modifying ligands on the surface of dendrimers, effective therapeutic and diagnostic platforms can be constructed and implemented for targeted delivery. Dendrimer-based nanocarriers also show great potential in gene delivery. Since enzymes can degrade genetic materials during their blood circulation, dendrimers exhibit promising packaging and delivery alternatives, particularly for central nervous system (CNS) treatments. The DNA and RNA encapsulated in dendrimers represented by polyamidoamine that are used for targeted brain delivery, via chemical-structural adjustments and appropriate generation, significantly improve the correlation between transfection efficiency and cytotoxicity. This article reports a comprehensive review of dendrimers' structures, synthesis processes, and biological applications. Recent progress in diagnostic imaging processes and therapeutic applications for cancers and other CNS diseases are presented. Potential challenges and future directions in the development of dendrimers, which provide the theoretical basis for their broader applications in healthcare, are also discussed.

Luminescent lanthanide(III) complexes of DTPA-bis(amido-phenyl-terpyridine) for bioimaging and phototherapeutic applications

We report here a series of coordinatively-saturated and thermodynamically stable luminescent [Ln(dtntp)(H₂O)] [Ln(III) = Eu (1), Tb (2), Gd (3), Sm (4) and Dy (5)] complexes using an aminophenyl-terpyridine appended-DTPA (dtntp) chelating ligand as cell imaging and photocytotoxic agents. The N,N″-bisamide derivative of H₅DTPA named as dtntp is based on 4'-(4-aminophenyl)-2,2':6',2″-terpyridine conjugated to diethylenetriamine-N,N',N″-pentaacetic acid. The structure, physicochemical properties, detailed photophysical aspects, interaction with DNA and serum proteins, and photocytotoxicity were studied. The intrinsic luminescence of Eu(III) and Tb(III) complexes due to f → f transitions used to evaluate their cellular uptake and distribution in cancer cells. The solid-state structure of [Eu(dtntp)(DMF)] (1·DMF) shows a discrete mononuclear molecule with nine-coordinated {EuN₃O₆} distorted tricapped-trigonal prism (TTP) coordination geometry around the Eu(III). The {EuN₃O₆} core results from three nitrogen atoms and three carboxylate oxygen atoms, and two carbonyl oxygen atoms of the amide groups of dtntp ligand. The ninth coordination site is occupied by an oxygen atom of DMF as a solvent from crystallization. The designed probes have two aromatic pendant phenyl-terpyridine (Ph-tpy) moieties as photo-sensitizing antennae to impart the desirable optical properties for cellular imaging and photocytotoxicity. The photostability, coordinative saturation, and energetically rightly poised triplet states of dtntp ligand allow the efficient energy transfer (ET) from Ph-tpy to the emissive excited states of the Eu(III)/Tb(III), makes them luminescent cellular imaging probes. The Ln(III) complexes show significant binding tendency to DNA (K ~ 10⁴ M^-1), and serum proteins (BSA and HSA) (K ~ 10⁵ M^-1). The luminescent Eu(III) (1) and Tb(III) (2) complexes were utilized for cellular internalization and cytotoxicity studies due to their optimal photophysical properties. The cellular uptake studies using fluorescence imaging displayed intracellular (cytosolic and nuclear) localization in cancer cells. The complexes 1 and 2 displayed significant photocytotoxicity in HeLa cells. These results offer a modular design strategy with further scope to utilize appended N,N,N-donor tpy moiety for developing light-responsive luminescent Ln(III) bioprobes for theranostic applications.

Recent Advances in Luminescence Imaging of Biological Systems Using Lanthanide(III) Luminescent Complexes

The use of luminescence in biological systems allows one to diagnose diseases and understand cellular processes. Molecular systems, particularly lanthanide(III) complexes, have emerged as an attractive system for application in cellular luminescence imaging due to their long emission lifetimes, high brightness, possibility of controlling the spectroscopic properties at the molecular level, and tailoring of the ligand structure that adds sensing and therapeutic capabilities. This review aims to provide a background in luminescence imaging and lanthanide spectroscopy and discuss selected examples from the recent literature on lanthanide(III) luminescent complexes in cellular luminescence imaging, published in the period 2016-2020. Finally, the challenges and future directions that are pointing for the development of compounds that are capable of executing multiple functions and the use of light in regions where tissues and cells have low absorption will be discussed.

Mitochondria-localizing dicarbohydrazide Ln complexes and their mechanism of in vitro anticancer activity

Dicarbohydrazide Ln complexes trigger SK-OV-3/DDP cell apoptosis via a mitochondrial dysfunction pathway.

A viscosity-sensitive iridium(iii) probe for lysosomal microviscosity quantification and blood viscosity detection in diabetic mice

A novel viscosity-sensitive iridium probe enables the detection of cancer and diabetes.