ROS-producing nanomaterial engineered from Cu(I) complexes with P2N2-ligands for cancer cells treating.

The work presents core-shell nanoparticles (NPs) built from the novel Cu(I) complexes with cyclic P2N2-ligands (1,5-diaza-3,7-diphosphacyclooctanes) that can visualize their entry into cancer and normal cells using a luminescent signal and treat cells by self-enhancing generation of reactive oxygen species (ROS). Variation of P- and N-substituents in the series of P2N2-ligands allows structure optimization of the Cu(I) complexes for the formation of the luminescent NPs with high chemical stability. The non-covalent modification of the NPs with triblock copolymer F-127 provides their high colloidal stability, followed by efficient cell internalization of the NPs visualized by their blue (⁓450 nm) luminescence. The cytotoxic effects of the NPs toward the normal and some of cancer cells are significantly lower than those of the corresponding molecular complexes, which correlates with the chemical stability of the NPs in the solutions. The ability of the NPs to self-enhanced and H2O2-induced ROS generation is demonstrated in solutions and intracellular space by means of the standard electron spin resonance (ESR) and fluorescence techniques correspondingly. The anticancer specificity of the NPs toward HuTu 80 cancer cells and the apoptotic cell death pathway correlate with the intracellular level of ROS, which agrees well with the self-enhancing ROS generation of the NPs. The enhanced level of ROS revealed in HuTu 80 cells incubated with the NPs can be associated with the significant level of their mitochondrial localization.

Carbonized Nickel Complex of Sodium Pectate as Catalyst for Proton-Exchange Membrane Fuel Cells.

Sodium pectate derivatives with 25% replacement of sodium ions with nickel ions were obtained by carbonization to temperatures of 280, 550, and 800 °C, under special protocols in an inert atmosphere by carbonization to temperatures of 280, 550, and 800 °C. The 25% substitution is the upper limit of substitution of sodium for nickel ions, above which the complexes are no longer soluble in water. It was established that the sample carburized to 550 °C is the most effective active element in the hydrogen-oxidation reaction, while the sample carbonized up to 800 °C was the most effective in the oxygen-reduction reaction. The poor performance of the catalytic system involving the pectin coordination biopolymer carbonized up to 280 °C was due to loss of proton conductivity caused by water removal and mainly by two-electron transfer in one catalytic cycle of the oxygen-reduction reaction. The improved performance of the system with coordination biopolymer carbonized up to 550 °C was due to the better access of gases to the catalytic sites and four-electron transfer in one catalytic cycle. The (Ni-NaPG)800C sample contains metallic nickel nanoparticles and loose carbon, which enhances the electrical conductivity and gas capacity of the catalytic system. In addition, almost four-electron transfer is observed in one catalytic cycle of the oxygen-reduction reaction.

Covalent Functionalization of Black Phosphorus Nanosheets with Dichlorocarbenes for Enhanced Electrocatalytic Hydrogen Evolution Reaction.

Two-dimensional black phosphorus (BP) has emerged as a perspective material for various micro- and opto-electronic, energy, catalytic, and biomedical applications. Chemical functionalization of black phosphorus nanosheets (BPNS) is an important pathway for the preparation of materials with improved ambient stability and enhanced physical properties. Currently, the covalent functionalization of BPNS with highly reactive intermediates, such as carbon-free radicals or nitrenes, has been widely implemented to modify the material's surface. However, it should be noted that this field requires more in-depth research and new developments. Herein, we report for the first time the covalent carbene functionalization of BPNS using dichlorocarbene as a functionalizing agent. The P-C bond formation in the obtained material (BP-CCl2) has been confirmed by Raman, solid-state 31P NMR, IR, and X-ray photoelectron spectroscopy methods. The BP-CCl2 nanosheets exhibit an enhanced electrocatalytic hydrogen evolution reaction (HER) performance with an overpotential of 442 mV at -1 mA cm-2 and a Tafel slope of 120 mV dec-1, outperforming the pristine BPNS.

Doping of Transparent Electrode Based on Oriented Networks of Nickel in Poly(3,4-Ethylenedioxythiophene) Polystyrene Sulfonate Matrix with P-Toluenesulfonic Acid.

This work aimed to obtain an optically transparent electrode based on the oriented nanonetworks of nickel in poly(3,4-ethylenedioxythiophene) polystyrene sulfonate matrix. Optically transparent electrodes are used in many modern devices. Therefore, the search for new inexpensive and environmentally friendly materials for them remains an urgent task. We have previously developed a material for optically transparent electrodes based on oriented platinum nanonetworks. This technique was upgraded to obtain a cheaper option from oriented nickel networks. The study was carried out to find the optimal electrical conductivity and optical transparency values of the developed coating, and the dependence of these values on the amount of nickel used was investigated. The figure of merit (FoM) was used as a criterion for the quality of the material in terms of finding the optimal characteristics. It was shown that doping PEDOT: PSS with p-toluenesulfonic acid in the design of an optically transparent electroconductive composite coating based on oriented nickel networks in a polymer matrix is expedient. It was found that the addition of p-toluenesulfonic acid to an aqueous dispersion of PEDOT: PSS with a concentration of 0.5% led to an eight-fold decrease in the surface resistance of the resulting coating.

Specific nanoarchitecture of silica nanoparticles codoped with the oppositely charged Mn2+ and Ru2+ complexes for dual paramagnetic-luminescent contrasting effects.

The silica nanoparticles (SNs) co-doped with paramagnetic ([Mn(HL)]n-,) and luminescent ([Ru(dipy)3]2+) complexes are represented. The specific distribution of [Mn(HL)]n- within the SNs allows to achieve about ten-fold enhancing in magnetic relaxivities in comparison with those of [Mn(HL)]n- in solutions. The leaching of [Mn(HL)]n- from the shell can be minimized through the co-doping of [Ru(dipy)3]2+ into the core of the SNs. The co-doped SNs exhibit colloid stability in aqueous solutions, including those modeling a blood serum. The surface of the co-doped SNs was also decorated by amino- and carboxy-groups. The cytotoxicity, hemoagglutination and hemolytic activities of the co-doped SNs are on the levels convenient for "in vivo" studies, although the amino-decorated SNs cause more noticeable agglutination and suppression of cell viability. The co-doped SNs being intravenously injected into mice allows to reveal their biodistribution in both ex vivo and in vivo conditions through confocal microscopy and magnetic resonance imaging correspondingly.

In-Situ Electrochemical Exfoliation and Methylation of Black Phosphorus into Functionalized Phosphorene Nanosheets.

Two-dimensional black phosphorus (BP) has attracted great attention as a perspective material for various applications. The chemical functionalization of BP is an important pathway for the preparation of materials with improved stability and enhanced intrinsic electronic properties. Currently, most of the methods for BP functionalization with organic substrates require either the use of low-stable precursors of highly reactive intermediates or the use of difficult-to-manufacture and flammable BP intercalates. Herein we report a facile route for simultaneous electrochemical exfoliation and methylation of BP. Conducting the cathodic exfoliation of BP in the presence of iodomethane makes it possible to generate highly active methyl radicals, which readily react with the electrode's surface yielding the functionalized material. The covalent functionalization of BP nanosheets with the P-C bond formation has been proven by various microscopic and spectroscopic methods. The functionalization degree estimated by solid-state 31P NMR spectroscopy analysis reached 9.7%.

Thymine-Modified Nanocarrier for Doxorubicin Delivery in Glioblastoma Cells.

Brain tumor glioblastoma is one of the worst types of cancer. The blood-brain barrier prevents drugs from reaching brain cells and shields glioblastoma from treatment. The creation of nanocarriers to improve drug delivery and internalization effectiveness may be the solution to this issue. In this paper, we report on a new nanocarrier that was developed to deliver the anticancer drug doxorubicin to glioblastoma cells. The nanocarrier was obtained by nanoemulsion polymerization of diallyl disulfide with 1-allylthymine. Diallyl disulfide is a redox-sensitive molecule involved in redox cell activities, and thymine is a uracil derivative and one of the well-known bioactive compounds that can enhance the pharmacological activity of doxorubicin. Doxorubicin was successfully introduced into the nanocarrier with a load capacity of about 4.6%. Biological studies showed that the doxorubicin nanocarrier composition is far more cytotoxic to glioblastoma cells (T98G) than it is to cancer cells (M-HeLa) and healthy cells (Chang liver). The nanocarrier improves the penetration of doxorubicin into T98G cells and accelerates the cells' demise, as is evident from flow cytometry and fluorescence microscopy data. The obtained nanocarrier, in our opinion, is a promising candidate for further research in glioblastoma therapy.

Complexation of Oligo- and Polynucleotides with Methoxyphenyl-Functionalized Imidazolium Surfactants.

Interaction between cationic surfactants and nucleic acids attracts much attention due to the possibility of using such systems for gene delivery. Herein, the lipoplexes based on cationic surfactants with imidazolium head group bearing methoxyphenyl fragment (MPI-n, n = 10, 12, 14, 16) and nucleic acids (oligonucleotide and plasmid DNA) were explored. The complex formation was confirmed by dynamic/electrophoretic light scattering, transmission electron microscopy, fluorescence spectroscopy, circular dichroism, and gel electrophoresis. The nanosized lipoplex formation (of about 100-200 nm), contributed by electrostatic, hydrophobic interactions, and intercalation mechanism, has been shown. Significant effects of the hydrocarbon tail length of surfactant and the type of nucleic acid on their interaction was revealed. The cytotoxic effect and transfection ability of lipoplexes studied were determined using M-HeLa, A549 cancer cell lines, and normal Chang liver cells. A selective reduced cytotoxic effect of the complexes on M-HeLa cancer cells was established, as well as a high ability of the systems to be transfected into cancer cells. MPI-n/DNA complexes showed a pronounced transfection activity equal to the commercial preparation Lipofectamine 3000. Thus, it has been shown that MPI-n surfactants are effective agents for nucleic acid condensation and can be considered as potential non-viral vectors for gene delivery.

Complexes of Sodium Pectate with Nickel for Hydrogen Oxidation and Oxygen Reduction in Proton-Exchange Membrane Fuel Cells.

A number of nickel complexes of sodium pectate with varied Ni2+ content have been synthesized and characterized. The presence of the proton conductivity, the possibility of the formation of a dense spatial network of transition metals in these coordination biopolymers, and the immobilization of transition ions in the catalytic sites of this class of compounds make them promising for proton-exchange membrane fuel cells. It has been established that the catalytic system composed of a coordination biopolymer with 20% substitution of sodium ions for divalent nickel ions, Ni (20%)-NaPG, is the leading catalyst in the series of 5, 15, 20, 25, 35% substituted pectates. Among the possible reasons for the improvement in performance the larger specific surface area of this sample compared to the other studied materials and the narrowest distribution of the vertical size of metal arrays were registered. The highest activity during CV and proximity to four-electron transfer during the catalytic cycle have also been observed for this compound.

pH-Driven Intracellular Nano-to-Molecular Disassembly of Heterometallic [Au2L2]{Re6Q8} Colloids (L = PNNP Ligand; Q = S2- or Se2-).

The present work introduces a simple, electrostatically driven approach to engineered nanomaterial built from the highly cytotoxic [Au2L2]2+ complex (Au2, L = 1,5-bis(p-tolyl)-3,7-bis(pyridine-2-yl)-1,5-diaza-3,7-diphosphacyclooctane (PNNP) ligand) and the pH-sensitive red-emitting [{Re6Q8}(OH)6]4- (Re6-Q, Q = S2- or Se2-) cluster units. The protonation/deprotonation of the Re6-Q unit is a prerequisite for the pH-triggered assembly of Au2 and Re6-Q into Au2Re6-Q colloids, exhibiting disassembly in acidic (pH = 4.5) conditions modeling a lysosomal environment. The counter-ion effect of polyethylenimine causes the release of Re6-Q units from the colloids, while the binding with lysozyme restricts their protonation in acidified conditions. The enhanced luminescence response of Re6-S on the disassembly of Au2Re6-S colloids in the lysosomal environment allows us to determine their high lysosomal localization extent through the colocalization assay, while the low luminescence of Re6-Se units in the same conditions allows us to reveal the rapture of the lysosomal membrane through the use of the Acridine Orange assay. The lysosomal pathway of the colloids, followed by their endo/lysosomal escape, correlates with their cytotoxicity being on the same level as that of Au2 complexes, but the contribution of the apoptotic pathway differentiates the cytotoxic effect of the colloids from that of the Au2 complex arisen from the necrotic processes.

Molecular and Nano-Structural Optimization of Nanoparticulate Mn2+-Hexarhenium Cluster Complexes for Optimal Balance of High T1- and T2-Weighted Contrast Ability with Low Hemoagglutination and Cytotoxicity.

The present work introduces rational design of nanoparticulate Mn(II)-based contrast agents through both variation of the µ3 (inner) ligands within a series of hexarhenium cluster complexes [{Re6(µ3-Q)8}(CN)6]4- (Re6Q8, Q = S2-, Se2- or Te2-) and interfacial decoration of the nanoparticles (NPs) K4-2xMnxRe6Q8 (x = 1.3 - 1.8) by a series of pluronics (F-68, P-123, F-127). The results highlight an impact of the ligand and pluronic for the optimal colloid behavior of the NPs allowing high colloid stability in ambient conditions and efficient phase separation under the centrifugation. It has been revealed that the K4-2xMnxRe6Se8 NPs and those decorated by F-127 are optimal from the viewpoint of magnetic relaxivities r1 and r2 (8.9 and 10.9 mM-1s-1, respectively, at 0.47 T) and low hemoagglutination activity. The insignificant leaching of Mn2+ ions from the NPs correlates with their insignificant effect on the cell viability of both M-HeLa and Chang Liver cell lines. The T1- and T2-weighted contrast ability of F-127-K4-2xMnxRe6Q8 NPs was demonstrated through the measurements of phantoms at whole body 1.5 T scanner.

Role of PSS-based assemblies in stabilization of Eu and Sm luminescent complexes and their thermoresponsive luminescence.

The present work introduces self-assembled polystyrenesulfonate (PSS) molecules as soft nanocapsules for incorporation of Eu3+-Sm3+ complexes by the solvent exchange procedure. The high levels of Eu3+- and Sm3+-luminescence of the complexes derives from the ligand-to-metal energy transfer, in turn, resulted from the complex formation of Eu3+and Sm3+ ions with the three recently synthesized cyclophanic 1,3-diketones. The structural features of the ligands are optimized for the high thermal sensitivity of Eu3+- luminescence in DMF solutions. The PSS-nanocapsules (∼100 nm) provide both colloid and chemical stabilization of the ultrasmall (3-5 nm) nanoprecipitates of the complexes, although their luminescence spectra patterns and excited state lifetimes differ from the values measured for the complexes in DMF solutions. The specific concentration ratio of the Eu3+-Sm3+ complexes in the DMF solutions allows to tune the intensity ratio of the luminescence bands at 612 and 650 nm in the heterometallic Eu3+-Sm3+ colloids. The thermal sensitivity of the Eu3+- and Sm3+-luminescence of the complexes derives from the static quenching both in PSS-colloids and in DMF solutions, while the thermo-induced dynamic quenching of the luminescence is significant only in DMF solutions. The reversibility of thermo-induced luminescence changes of the Eu3+-Sm3+ colloids is demonstrated by six heating-cooling cycles. The DLS measurements before and after the six cycles reveal the invariance of the PSS-based capsule as the prerequisite for the recyclability of the temperature monitoring through the ratio of Eu3+-to- Sm3+ luminescence.

Cationic Imidazolium Amphiphiles Bearing a Methoxyphenyl Fragment: Synthesis, Self-Assembly Behavior, and Antimicrobial Activity.

Novel cationic amphiphiles of the 3-alkyl-1-(4-methoxyphenyl)-1H-imidazol-3-ium bromide series bearing methoxyphenyl fragments (MPI-n) have been synthesized. Their aggregation properties in aqueous solutions, solubilization capacity, and hemolytic and antimicrobial activities have been investigated by a number of physicochemical methods. Using tensiometry, conductometry, and fluorescence spectroscopy, it was shown that the MPI-n have lower CMCs than their nonfunctionalized counterparts. The unusual alkyl-chain-length-dependent morphology of aggregates is testified for this homological series. Amphiphiles with 12, 14, and 16 alkyl tails are characterized by the formation of micellar aggregates, while a surfactant with a decyl tail is characterized by the formation of larger aggregates with lower surface curvature. The MPI-10 aggregate morphology was rationalized in terms of the packing parameter consideration and was supported by size measurements and the fluorescence probe techniques, which showed that vesicle-like aggregates in close-packing mode probably occur. MPI-n aggregates have exhibited a high solubilization capacity toward hydrophobic azo dye Orange OT. Importantly, amphiphiles studied showed (i) high bacteriostatic activity at the level of ciprofloxacin; (ii) high bactericidal action against all Gram-positive bacteria, including methicillin-resistant strains; (iii) bactericidal properties against Gram-negative bacteria; and (iv) low hemolytic activity.

Self-Assembling Metallocomplexes of the Amphiphilic 1,4-Diazabicyclo[2.2.2]octane Derivative as a Platform for the Development of Nonplatinum Anticancer Drugs.

New 1-cetyl-4-aza-1-azoniabicyclo[2.2.2]octane bromide complexes with copper(II) bromide and lanthanum(III) nitrate were characterized using dynamic light scattering and transmission electron microscopy, with self-assembly and the morphological behavior elucidated. For the lanthanum(III) nitrate complex, the 3D crystal structure was characterized using X-ray diffractometry. These metallosurfactants were tested as antitumor agents, and a high cytotoxic effect comparable with doxorubicin was revealed against the M-HeLa and A-549 cell lines. Both complexes were 2 times more active toward the MCF-7 cell line than the breast cancer drug tamoxifen. The cytotoxic mechanism of complexes is assumed to be related to the induction of apoptosis through the mitochondrial pathway.

Single Excited Dual Band Luminescent Hybrid Carbon Dots-Terbium Chelate Nanothermometer.

The report introduces hybrid polyelectrolyte-stabilized colloids combining blue and green-emitting building blocks, which are citrate carbon dots (CDs) and [TbL]+ chelate complexes with 1,3-diketonate derivatives of calix[4]arene. The joint incorporation of green and blue-emitting blocks into the polysodium polystyrenesulfonate (PSS) aggregates is carried out through the solvent-exchange synthetic technique. The coordinative binding between Tb3+ centers and CD surface groups in initial DMF solutions both facilitates joint incorporation of [TbL]+ complexes and the CDs into the PSS-based nanobeads and affects fluorescence properties of [TbL]+ complexes and CDs, as well as their ability for temperature sensing. The variation of the synthetic conditions is represented herein as a tool for tuning the fluorescent response of the blue and green-emitting blocks upon heating and cooling. The revealed regularities enable developing either dual-band luminescent colloids for monitoring temperature changes within 25-50 °C through double color emission or transforming the colloids into ratiometric temperature sensors via simple concentration variation of [TbL]+ and CDs in the initial DMF solution. Novel hybrid carbon dots-terbium chelate PSS-based nanoplatform opens an avenue for a new generation of sensitive and customizable single excited dual-band nanothermometers.

Structure impact on photodynamic therapy and cellular contrasting functions of colloids constructed from dimeric Au(I) complex and hexamolybdenum clusters.

Electrostatically driven self-assembly of [Au2L2]2+ (L is cyclic PNNP ligand) with [{Mo6I8}(L')6]2- (L' = I-, CH3COO-) in aqueous solutions is introduced as facile route for combination of therapeutic and cellular contrasting functions within heterometallic colloids (Mo6-Au2). The nature of L' affects the size and aggregation behavior of crystalline Mo6-Au2 aggregates, which in turn affect the luminescence of the cluster units incorporated into Mo6-Au2 colloids. The spin trap facilitated electron spin resonance spectroscopy technique indicates that the level of ROS generated by Mo6-Au2 colloids is also affected by their size. Both (L' = I-, CH3COO-) Mo6-Au2 colloids undergo cell internalization, which is enhanced by their assembly with poly-DL-lysine (PL) for L' = CH3COO-, but remains unchanged for L' = I-. The colloids PL-Mo6-Au2 (L' = CH3COO-) are visualized as huge crystalline aggregates both outside and inside the cell cytoplasm by confocal microscopy imaging of the incubated cells, while the smaller sized (30-50 nm) PL-Mo6-Au2 (L' = I-) efficiently stain the cell nuclei. Quantitative colocalization analysis of PL-Mo6-Au2 (L' = CH3COO-) in lysosomal compartments points to the fast endo-lysosomal escape of the colloids followed by their intracellular aggregation. The cytotoxicity of PL-Mo6-Au2 differs from that of Mo6 and Au2 blocks, predominantly acting through apoptotic pathway. The photodynamic therapeutic effect of the PL-Mo6-Au2 colloids on the cancer cells correlates with their intracellular trafficking and aggregation.

Cationic liposomes mediated transdermal delivery of meloxicam and ketoprofen: Optimization of the composition, in vitro and in vivo assessment of efficiency.

New liposomes modified with pyrrolidinium surfactants containing a hydroxyethyl fragment (CnPB, n = 12, 14, 16) were prepared for transdermal delivery of non-steroidal anti-inflammatory drugs. In order to obtain the optimal composition, the surfactant/lipid molar ratio (0.02/1; 0.029/1; 0.04/1) and the amphiphile hydrocarbon tail length were varied. Rhodamine B was loaded in all formulations, while meloxicam and ketoprofen in selected ones. For liposomes studied the hydrodynamic diameter was in the range of 80-130 nm, the zeta potential ranged from +35 to +50 mV, EE was 75-99%. Liposome modification leads to a prolonged release of the rhodamine B (up to 10-12 h) and faster release of non-steroidal drugs (up to 7-8 h) in vitro. The ability to cross the skin barrier using Franz cells was investigated for liposomal meloxicam and ketoprofen. The total amount of meloxicam and ketoprofen passed through the Strat-M® membranes during 51 h was 51-114 µg/cm2 and 87-105 µg/cm2 respectively. The evaluation of transdermal diffusion ex vivo showed that total amount of liposomal ketoprofen passed through the skin during 51 h was 140-162 µg/cm2. Liposomes modified with C16PB were found as the most effective inflammation reducing formulation in the carrageenan edema model of rat paw.

Surface modification of silica nanoparticles by hexarhenium anionic cluster complexes for pH-sensing and staining of cell nuclei.

The surface deposition of luminescent anionic cluster complex [{Re6S8}(OH)6]4- advantages to the design and synthesis of composite luminescent silica nanoparticles (SNs) for intracellular imaging and sensing, while the encapsulation of the cluster units into SNs lacks for efficient luminescence. The deposition of the Re6 clusters resulted from their assembly at the silica surface functionalized by amino-groups provides the synthetic route for the composite SNs with bright cluster-centered luminescence invariable in pH range from 4.0 to 12.0. The pH-dependent supramolecular assembly of the cluster units with polyethyleneimine (PEI) at the silica surface is an alternative route for the synthesis of the composite SNs with high cluster-centered luminescence sensitive to pH-changes within 4.0-6.0. The sensitivity derives from the pH-driven conformational changes of PEI chains resulting in the release of the clusters from the PEI-based confinement under the acidification within pH 6.0-4.0. The potential of the composite SNs in cellular contrasting has been also revealed by the cell viability and flow cytometry measurements. It has been found that the PEI-supported embedding of the cluster units facilitates cell internalization of the composite SNs as well as results in specific intracellular distribution manifested by efficient staining of the cell nuclei in the confocal images.

Oriented Nickel Nanonetworks and Their Submicron Fibres as a Basis for a Transparent Electrically Conductive Coating.

The paper demonstrates a technique for applying an oriented nickel network to a glass surface. The method is based on the chemical reduction of nickel salt. The shaping and orientation of the resulting system are carried out using a micellar template of a surfactant and a magnetic field. Submicron nickel fibres are used to impart unity to the plurality of individual-oriented nickel nanonetworks. The result is a single conductive coating on the surface of the glass, which has a transparency in the optical range. Investigations of the structure, chemical composition, morphology and electrical conductivity of the coating were performed.

Terbium(III)-thiacalix[4]arene nanosensor for highly sensitive intracellular monitoring of temperature changes within the 303-313 K range.

The work introduces hydrophilic PSS-[Tb2(TCAn)2] nanoparticles to be applied as highly sensitive intracellular temperature nanosensors. The nanoparticles are synthesized by solvent-induced nanoprecipitation of [Tb2(TCAn)2] complexes (TCAn - thiacalix[4]arenes bearing different upper-rim substituents: unsubstituted TCA1, tert-buthyl-substituted TCA2, di- and tetra-brominated TCA3 and TCA4) with the use of polystyrenesulfonate (PSS) as stabilizer. The temperature responsive luminescence behavior of PSS-[Tb2(TCAn)2] within 293-333 K range in water is modulated by reversible changes derived from the back energy transfer from metal to ligand (M* → T1) correlating with the energy gap between the triplet levels of ligands and resonant 5D4 level of Tb3+ ion. The lowering of the triplet level (T1) energies going from TCA1 and TCA2 to their brominated counterparts TCA3 and TCA4 facilitates the back energy transfer. The highest ever reported temperature sensitivity for intracellular temperature nanosensors is obtained for PSS-[Tb2(TCA4)2] (SI = 5.25% K-1), while PSS-[Tb2(TCA3)2] is characterized by a moderate one (SI = 2.96% K-1). The insignificant release of toxic Tb3+ ions from PSS-[Tb2(TCAn)2] within heating/cooling cycle and the low cytotoxicity of the colloids point to their applicability in intracellular temperature monitoring. The cell internalization of PSS-[Tb2(TCAn)2] (n = 3, 4) marks the cell cytoplasm by green Tb3+-luminescence, which exhibits detectable quenching when the cell samples are heated from 303 to 313 K. The colloids hold unprecedented potential for in vivo intracellular monitoring of temperature changes induced by hyperthermia or pathological processes in narrow range of physiological temperatures.