Microcalorimetric measurements carried out on isolated tumorous and nontumorous tissue samples from organs in the urogenital tract in comparison to histological and impulse-cytophotometric investigations

Cell-resistant wavelength-shifting molecular beacons made of L-DNA and a clickable L-configured uridine

Wavelength-shifting molecular beacons were prepared from L-DNA. The clickable anchor for the two dyes, Cy3 and Cy5, was 2'-O-propargyl-L-uridine and was synthesized from L-ribose. Four clickable molecular beacons were prepared and double-modified with the azide dyes by a combination of click chemistry on a solid support for Cy3 during DNA synthesis and postsynthetic click chemistry for Cy5 in solution. Cy3 and Cy5 successfully formed a FRET pair in the beacons, and the closed form (red fluorescence) and the open form (green fluorescence) can be distinguished by the two-color fluorescence readout. Two molecular beacons were identified to show the greatest fluorescence contrast in temperature-dependent fluorescence measurements. The stability of the L-configured molecular beacons was demonstrated after several heating and cooling cycles as well as in the cell lysate. In comparison, D-configured molecular beacons showed a rapid decrease of fluorescence contrast in the cell lysate, which is caused by the opening of the beacons, probably due to degradation. This was confirmed in cell experiments using confocal microscopy. The L-configured molecular beacons are potential intracellular thermometers for future applications.

Cellular Thermal Biology Using Fluorescent Nanothermometers

It has been known that cells have mechanisms to sense and respond to environmental noxiousness and mild temperature changes, such as heat shock response and thermosensitive TRP channels. Meanwhile, new methods of measuring temperature at the cellular level has recently been developed using fluorescent nanothermometers. Among these thermometers, fluorescent polymeric thermometers and fluorescent nanodiamonds excel in the properties required for intracellular thermometry. By using these novel methods to measure the temperature of single cells in cultures and tissues, it was revealed that spontaneous spatiotemporal temperature fluctuations occur within cells. Furthermore, the temperature fluctuations were related to organelles such as mitochondria and cellular and physiological functions, revealing a close relationship between intracellular temperature and cellular functions.

Recent progress on small molecular temperature-sensitive fluorescent probes

Temperature is an important biophysical parameter that is closely related with the metabolic activity in living cells. Therefore, the detection of intracellular temperature changes is crucial for exploring temperature-related biological processes. Fluorescence probe is an ideal tool for observing temperature changes in cells, which has many advantages, such as high sensitivity, good selectivity, and noninvasive, and thus aroused the great interest of researchers. In this paper, we summarize the recent progress of organic small molecule temperature-sensitive fluorescence probes in recent years was reviewed. Particularly, we describe the common response mode to the temperature and the practical applications of the probe in living cells and even animal models. Moreover, an outlook regarding temperature detection in clinical applications is discussed. The temperature-sensitive fluorescent probe is a "black box" to many researchers. This review aims to open a window on the prospect of the noninvasive in vivo detection of temperature which is helpful to deeper understand this rich research area.

Intracellular Aβ42 Aggregation Leads to Cellular Thermogenesis

The aggregation of Aβ42 is a hallmark of Alzheimer’s disease. It is still not known what the biochemical changes are inside a cell which will eventually lead to Aβ42 aggregation. Thermogenesis has been associated with cellular stress, the latter of which may promote aggregation. We perform intracellular thermometry measurements using fluorescent polymeric thermometers to show that Aβ42 aggregation in live cells leads to an increase in cell-averaged temperatures. This rise in temperature is mitigated upon treatment with an aggregation inhibitor of Aβ42 and is independent of mitochondrial damage that can otherwise lead to thermogenesis. With this, we present a diagnostic assay which could be used to screen small-molecule inhibitors to amyloid proteins in physiologically relevant settings. To interpret our experimental observations and motivate the development of future models, we perform classical molecular dynamics of model Aβ peptides to examine the factors that hinder thermal dissipation. We observe that this is controlled by the presence of ions in its surrounding environment, the morphology of the amyloid peptides, and the extent of its hydrogen-bonding interactions with water. We show that aggregation and heat retention by Aβ peptides are favored under intracellular-mimicking ionic conditions, which could potentially promote thermogenesis. The latter will, in turn, trigger further nucleation events that accelerate disease progression.

A facile combinatorial approach to construct a ratiometric fluorescent sensor: application for the real-time sensing of cellular pH changes

Realtime monitoring of the cellular environment, such as the intracellular pH, in a defined cellular space provides a comprehensive understanding of the dynamics processes in a living cell. Considering the limitation of spatial resolution in conventional microscopy measurements, multiple types of fluorophores assembled within that space would behave as a single fluorescent probe molecule. Such a character of microscopic measurements enables a much more flexible combinatorial design strategy in developing fluorescent probes for given targets. Nanomaterials with sizes smaller than the microscopy spatial resolution provide a scaffold to assemble several types of fluorophores with a variety of optical characteristics, therefore providing a convenient strategy for designing fluorescent pH sensors. In this study, fluorescein (CF) and tetramethylrhodamine (CR) were assembled on a DNA nanostructure with controlling the number of each type of fluorophore. By taking advantage of the different responses of CF and CR emissions to the pH environment, an appropriate assembly of both CF and CR on DNA origami enabled a controlled intensity of fluorescence emission and ratiometric pH monitoring within the space defined by DNA origami. The CF and CR-assembled DNA origami was successfully applied for monitoring the intracellular pH changes.

Lanthanide doped luminescence nanothermometers in the biological windows: strategies and applications

The development of lanthanide-doped non-contact luminescent nanothermometers with accuracy, efficiency and fast diagnostic tools attributed to their versatility, stability and narrow emission band profiles has spurred the replacement of conventional contact thermal probes. The application of lanthanide-doped materials as temperature nanosensors, excited by ultraviolet, visible or near infrared light, and the generation of emissions lying in the biological window regions, I-BW (650 nm-950 nm), II-BW (1000 nm-1350 nm), III-BW (1400 nm-2000 nm) and IV-BW (centered at 2200 nm), are notably growing due to the advantages they present, including reduced phototoxicity and photobleaching, better image contrast and deeper penetration depths into biological tissues. Here, the different mechanisms used in lanthanide ion-doped nanomaterials to sense temperature in these biological windows for biomedical and other applications are summarized, focusing on factors that affect their thermal sensitivity, and consequently their temperature resolution. Comparing the thermometric performance of these nanomaterials in each biological window, we identified the strategies that allow boosting of their sensing properties.

Cell Temperature Measurement for Biometabolism Monitoring

Temperature is an important factor in the process of life, as thermal energy transfer participates in all biological events in organisms. Due to technical limitations, there is still a lot more information to be explored regarding the correlation between life activities and temperature changes. In recent years, the emergence of a variety of new temperature measurement methods has facilitated further research in this field. Here, we introduce the latest advances in temperature sensors for biological detection and their related applications in metabolic research. Various technologies are discussed in terms of their advantages and shortcomings, and future prospects are presented.

Intracellular Thermometry at the Micro-/Nanoscale and its Potential Application to Study Protein Aggregation Related to Neurodegenerative Diseases

Temperature is a fundamental physical parameter that influences biological processes in living cells. Hence, intracellular temperature mapping can be used to derive useful information reflective of thermodynamic properties and cellular behaviour. Herein, existing publications on different thermometry systems, focusing on those that employ fluorescence-based techniques, are reviewed. From developments based on fluorescent proteins and inorganic molecules to metal nanoclusters and fluorescent polymers, the general findings of intracellular measurements from different research groups are discussed. Furthermore, the contradiction of mitochondrial thermogenesis and nuclear-cytoplasmic temperature differences to current thermodynamic understanding are highlighted. Lastly, intracellular thermometry is proposed as a tool to quantify the energy flow and cost associated with amyloid-β42 (Aβ42) aggregation, a hallmark of Alzheimer's disease.

Temperature Sensing in Cells Using Polymeric Upconversion Nanocapsules

Monitoring local temperature inside cells is crucial when interpreting biological activities as enhanced cellular metabolism leads to higher heat production and is commonly correlated with the presence of diseases such as cancer. In this study, we report on polymeric upconversion nanocapsules for potential use as local nanothermometers in cells by exploiting the temperature dependence of the triplet-triplet annihilation upconversion phenomenon. Nanocapsules synthesized by the miniemulsion solvent evaporation technique are composed of a polymer shell and a liquid core of rice bran oil, hosting triplet-triplet annihilation upconversion active dyes as sensitizer and emitter molecules. The sensitivity of the triplet-triplet annihilation upconversion to the local oxygen concentration was overcome by the oxygen reduction ability of the rice bran oil core. The triplet-triplet annihilation upconversion process could thus successfully be applied at different levels of oxygen presence including at ambient conditions. Using this method, the local temperature within a range of 22 to 40 °C could be determined when the upconversion nanocapsules were taken up by HeLa cells with good cellular viability. Thus, the higher cell temperatures where the cells show enhanced metabolic activity led to a significant increase in the delayed fluorescence spectrum of the upconversion nanocapsules. These findings are promising for further development of novel treatment and diagnostic tools in medicine.

A naphthalimide-based thermometer: heat-induced fluorescence “turn-on” sensing in a wide temperature range in ambient atmosphere

A heat-induced fluorescent “turn-on” sensor based on naphthalimide, NapPT-1, in which thioether chains were joined at the 4-site of naphthalimide, was designed and synthesized.

Water-soluble poly(N-isopropylacrylamide) nanoparticles grafted to trivalent lanthanide complexes as highly sensitive ratiometric nanothermometers

A new water-soluble, luminescent ratiometric nanothermometer with a tunable temperature-responsive range, high thermal sensitivity and good repeatability was designed and synthesized by grafting lanthanide complexes to pNIPAM polymeric nanoparticles.

Optical Detection of Intracellular Quantities Using Nanoscale Technologies

Optical probes that can be used to measure certain quantities with subcellular resolution give us access to a new level of information at which physics, chemistry, life sciences, and medicine become strongly intertwined. The emergence of these new technologies is owed to great advances in the physical sciences. However, evaluating and improving these methods to new standards requires a joint effort with life sciences and clinical practice. In this Account, we give an overview of the probes that have been developed for measuring a few highly relevant parameters at the subcellular scale: temperature, pH, oxygen, free radicals, inorganic ions, genetic material, and biomarkers. Luminescent probes are available in many varieties, which can be used for measuring temperature, pH, and oxygen. Since they are influenced by virtually any metabolic process in the healthy or diseased cell, these quantities are extremely useful to understand intracellular processes. Probes for them can roughly be divided into molecular dyes with a parameter dependent fluorescence or phosphorescence and nanoparticle platforms. Nanoparticle probes can provide enhanced photostability, measurement quality, and potential for multiple functionalities. Embedding into coatings can improve biocompatibility or prevent nonspecific interactions between the probe and the cellular environment. These qualities need to be matched however with good uptake properties, colloidal properties and eventually intracellular targeting to optimize their practical applicability. Inorganic ions constitute a broad class of compounds or elements, some of which play specific roles in signaling, while others are toxic. Their detection is often difficult due to the cross-talk with similar ions, as well as other parameters. The detection of free radicals, DNA, and biomarkers at extremely low levels has significant potential for biomedical applications. Their presence is linked more directly to physiological and clinical manifestations. Since existing methods for free radical detection are generally poor in sensitivity and spatiotemporal resolution, new reliable methods that are generally applicable can contribute greatly to advancing this topic in biology. Optical methods that detect DNA or RNA and protein biomarkers exist for intracellular applications, but are mostly relevant for the development of rapid point-of-care sample testing. To elucidate the inner workings of cells, focused multidisciplinary research is required to define the validity and limitations of a nanoparticle probe, in both physical and biological terms. Multifunctional platforms and those that are easily made compatible with conventional research equipment have an edge over other techniques in growing the body of research evidencing their versatility.

Nd3+-Doped BiVO4 luminescent nanothermometers of high sensitivity

Neodymium-doped BiVO₄ nanoparticles are explored for luminescent nanothermometry in the first and second biological windows. The nanothermometer sensitivity can be increased by an order of magnitude through careful selection of excitation wavelength and emission peaks, leading to sub-degree resolution and penetration depth up to 6 mm in biological tissues.

Thermal sensing in fluid at the micro-nano-scales

Temperature is one of the most fundamental parameters for the characterization of a physical system. With rapid development of lab-on-a-chip and biology at single cell level, a great demand has risen for the temperature sensors with high spatial, temporal, and thermal resolution. Nevertheless, measuring temperature in liquid environment is always a technical challenge. Various factors may affect the sensing results, such as the fabrication parameters of built-in sensors, thermal property of electrical insulating layer, and stability of fluorescent thermometers in liquid environment. In this review, we focused on different kinds of micro/nano-thermometers applied in the thermal sensing for microfluidic systems and cultured cells. We discussed the advantages and limitations of these thermometers in specific applications and the challenges and possible solutions for more accurate temperature measurements in further studies.

Intracellular thermometry with fluorescent sensors for thermal biology

Temperature influences the activities of living organisms at various levels. Cells not only detect environmental temperature changes through their unique temperature-sensitive molecular machineries but also muster an appropriate response to the temperature change to maintain their inherent functions. Despite the fundamental involvement of temperature in physiological phenomena, the mechanism by which cells produce and use heat is largely unknown. Recently, fluorescent thermosensors that function as thermometers in live cells have attracted much attention in biology. These new tools, made of various temperature-sensitive molecules, have allowed for intracellular thermometry at the single-cell level. Intriguing spatiotemporal temperature variations, including organelle-specific thermogenesis, have been revealed with these fluorescent thermosensors, which suggest an intrinsic connection between temperature and cell functions. Moreover, fluorescent thermosensors have shown that intracellular temperature changes at the microscopic level are largely different from those assumed for a water environment at the macroscopic level. Thus, the employment of fluorescent thermosensors will uncover novel mechanisms of intracellular temperature-assisted physiological functions.

Microcirculation-mediated preconditioning and intracellular hypothermia

Microcirculation is a network of perfused capillaries that connects macrocirculation with the cells. Although research has provided insight into microcirculatory blood flow, our knowledge remains limited. In this article, we propose a new role of microcirculation in physiological and shock states. In healthy individuals, microcirculation maintains cellular homeostasis via preconditioning. When blood volume decreases, the ensuing microcirculatory changes result in heterogeneity of perfusion and tissue oxygenation. Initially, this is partly compensated by the preserved autoregulation and the increase in the metabolism rate of cells, but at later stages, the loss of autoregulation activates the cascade of intracellular hypothermia.

Cancer is an adaptation that selects in animals against energy dissipation

As cancer usually follows reproduction, it is generally assumed that cancer does not select. Graham has however argued that juvenile cancer, which precedes reproduction, could during evolution have implemented a "cancer selection" that resulted in novel traits that suppress this juvenile cancer; an example is protection against UV sunlight-induced cancer, required for the emergence of terrestrial animals from the sea. We modify the cancer selection mechanism to the posited "cancer adaptation" mechanism, in which juvenile mortality is enhanced through the diminished care received by juveniles from their (grand) parents when these suffer from cancer in old age. Moreover, it is posited that the cancer adaptation selects against germline "dissipative genes", genes that result in enhanced free energy dissipation. Cancer's progression is interpreted as a cascade at increasing scale of repeated amplification of energy dissipation, a cascade involving heat shock, the Warburg effect, the cytokine IL-6, tumours, and hypermetabolism. Disturbance of any physiological process must enhance energy dissipation if the animal remains functioning normally, what explains multicausality, why "everything gives you cancer". The hypothesis thus comprises two newly invoked partial processes-diminished (grand) parental care and dissipation amplification-and results in a "selection against enhanced energy dissipation" which gives during evolution the benefit of energy conservation. Due to this benefit, cancer would essentially be an adaptation, and not a genetic disease, as assumed in the "somatic mutation theory". Cancer by somatic mutations is only a side process. The cancer adaptation hypothesis is substantiated by (1) cancer's extancy, (2) the failure of the somatic mutation theory, (3) cancer's initiation by a high temperature, (4) the interpretation of cancer's progression as a thermal process, and (5) the interpretation of tumours as organs that implement thermogenesis. The hypothesis could in principle be verified by monitoring in a population over several generations (1) the presence of dissipative genes, (2) the incidence of cancer, and (3) the beneficial effect of dissipative gene removal by cancer on starvation/famine survival.

Inorganic/polymer hybrid nanoparticles for sensing applications

This paper reviews a wide set of sensing applications based on the special properties associated with inorganic/polymer composite nanoparticles. We first describe optical sensing applications performed with hybrid nanoparticles and hybrid microgels with special emphasis on photoluminescence detection and imaging. Analyte detection with molecularly imprinted polymers and HPLC-based sensing using hybrid nanoparticles as stationary phase is also summarized. The final part is devoted to the study of ultra-sensitive molecule detection by surface-enhanced Raman spectroscopy using core-shell hybrid materials composed of noble metal nanoparticles and cross-linked polymers.

An engineered thermo-sensitive nanohybrid particle for accurate temperature sensing at the single-cell level and biologically controlled thermal therapy

A novel type of thermo-sensitive nanohybrid particle was developed for intracellular temperature sensing, as well as temperature-controlled drug release.

Isothermal microcalorimetry accurately detects bacteria, tumorous microtissues, and parasitic worms in a label-free well-plate assay

Isothermal microcalorimetry is a label-free assay that allows monitoring of enzymatic and metabolic activities. The technique has strengths, but most instruments have a low throughput, which has limited their use for bioassays. Here, an isothermal microcalorimeter, equipped with a vessel holder similar to a 48-well plate, was used. The increased throughput of this microcalorimeter makes it valuable for biomedical and pharmaceutical applications. Our results show that the sensitivity of the instrument allows the detection of 3 × 10(4) bacteria per vial. Growth of P. mirabilis in Luria Broth medium was detected between 2 and 9 h with decreasing inoculum. The culture released 2.1J with a maximum thermal power of 76 μW. The growth rate calculated using calorimetric and spectrophotometric data were 0.60 and 0.57 h(-1) , respectively. Additional insight on protease activities of P. mirabilis matching the last peak in heat production could be gathered as well. Growth of tumor microtissues releasing a maximum thermal power of 2.1 μW was also monitored and corresponds to a diameter increase of the microtissues from ca. 100 to 428 μm. This opens new research avenues in cancer research, diagnostics, and development of new antitumor drugs. For parasitic worms, the technique allows assessment of parasite survival using motor and metabolic activities even with a single worm.

A nano-stripe based sensor for temperature measurement at the submicrometer and nano scales

Submicrometer dual-stripe temperature sensors made from a single piece of metal thin film (e.g., Pd) are developed. With the narrowest sensor being 900 nm in width, they show sensitivity of 1-2 μV/K for the full range of 10-300 K. The results confirm the size effect in Seebeck coefficient previously observed in microstripe sensors of the same device configuration.

Temperature-Responsive Fluorescence Polymer Probes with Accurate Thermally Controlled Cellular Uptakes

Poly(N-isopropylacrylamide) (PNIPAAm)-based temperature-responsive fluorescence polymer probes were developed using radical polymerization, with 3-mercaptopropionic acid as the chain-transfer agent, followed by activation of terminal carboxyl groups with N-hydroxysuccinimide and reaction with 5-aminofluorescein (FL). The lower critical solution temperatures (LCSTs) of the resulting fluorescent polymer probes differed depending on the copolymer composition, and had a sharp phase-transition (hydrophilic/hydrophobic) boundary at the LCST. The cellular uptakes of the fluorescent polymer probes were effectively suppressed below the LCST, and increased greatly above the LCST. In particular, the cellular uptake of a copolymer with N,N-dimethylaminopropylacrylamide, P(NIPAAm-co-DMAPAAm2%)-FL (LCST: 37.4 °C), can be controlled within only 1 °C near body temperature, which is suitable for biological applications. These results indicated that the cellular uptakes of thermoresponsive polymers could be accurately controlled by the temperature, and such polymers have potential applications in discriminating between normal and pathological cells, and in intracellular drug delivery systems with local hyperthermia.

[Areas of application of isothermal microcalorimetry in urology: an overview]

Isothermal microcalorimetry (IMC) is a nonspecific analytical tool for measurement of heat. With sensitivity in the order of 0.2 μW, IMC can detect very small amounts of heat produced by only a small number of microorganisms or eukaryotic cells. This report is intended to introduce IMC to the urological audience and to give an overview about the past, present and future of this cutting edge technology in the urological context.

Glycoconjugated porphyrin dimers as robust ratiometric temperature sensors

We report the properties of glycoconjugated porphyrin dimers behaving as highly sensitive ratiometric temperature sensors in water.

High resolution fluorescence imaging of cancers using lanthanide ion-doped upconverting nanocrystals

During the last decade inorganic luminescent nanoparticles that emit visible light under near infrared (NIR) excitation (in the biological window) have played a relevant role for high resolution imaging of cancer. Indeed, semiconductor quantum dots (QDs) and metal nanoparticles, mostly gold nanorods (GNRs), are already commercially available for this purpose. In this work we review the role which is being played by a relatively new class of nanoparticles, based on lanthanide ion doped nanocrystals, to target and image cancer cells using upconversion fluorescence microscopy. These nanoparticles are insulating nanocrystals that are usually doped with small percentages of two different rare earth (lanthanide) ions: The excited donor ions (usually Yb3+ ion) that absorb the NIR excitation and the acceptor ions (usually Er3+, Ho3+ or Tm3+), that are responsible for the emitted visible (or also near infrared) radiation. The higher conversion efficiency of these nanoparticles in respect to those based on QDs and GNRs, as well as the almost independent excitation/emission properties from the particle size, make them particularly promising for fluorescence imaging. The different approaches of these novel nanoparticles devoted to "in vitro" and "in vivo" cancer imaging, selective targeting and treatment are examined in this review.

Thermometry at the nanoscale

Non-invasive precise thermometers working at the nanoscale with high spatial resolution, where the conventional methods are ineffective, have emerged over the last couple of years as a very active field of research. This has been strongly stimulated by the numerous challenging requests arising from nanotechnology and biomedicine. This critical review offers a general overview of recent examples of luminescent and non-luminescent thermometers working at nanometric scale. Luminescent thermometers encompass organic dyes, QDs and Ln(3+)ions as thermal probes, as well as more complex thermometric systems formed by polymer and organic-inorganic hybrid matrices encapsulating these emitting centres. Non-luminescent thermometers comprise of scanning thermal microscopy, nanolithography thermometry, carbon nanotube thermometry and biomaterials thermometry. Emphasis has been put on ratiometric examples reporting spatial resolution lower than 1 micron, as, for instance, intracellular thermometers based on organic dyes, thermoresponsive polymers, mesoporous silica NPs, QDs, and Ln(3+)-based up-converting NPs and β-diketonate complexes. Finally, we discuss the challenges and opportunities in the development for highly sensitive ratiometric thermometers operating at the physiological temperature range with submicron spatial resolution.

Nonthermal ATP-dependent fluctuations contribute to the in vivo motion of chromosomal loci

Chromosomal loci jiggle in place between segregation events in prokaryotic cells and during interphase in eukaryotic nuclei. This motion seems random and is often attributed to brownian motion. However, we show here that locus dynamics in live bacteria and yeast are sensitive to metabolic activity. When ATP synthesis is inhibited, the apparent diffusion coefficient decreases, whereas the subdiffusive scaling exponent remains constant. Furthermore, the magnitude of locus motion increases more steeply with temperature in untreated cells than in ATP-depleted cells. This "superthermal" response suggests that untreated cells have an additional source of molecular agitation, beyond thermal motion, that increases sharply with temperature. Such ATP-dependent fluctuations are likely mechanical, because the heat dissipated from metabolic processes is insufficient to account for the difference in locus motion between untreated and ATP-depleted cells. Our data indicate that ATP-dependent enzymatic activity, in addition to thermal fluctuations, contributes to the molecular agitation driving random (sub)diffusive motion in the living cell.

Hybrid micro-/nanogels for optical sensing and intracellular imaging

Hybrid micro-/nanogels are playing an increasing important part in a diverse range of applications, due to their tunable dimensions, large surface area, stable interior network structure, and a very short response time. We review recent advances and challenges in the developments of hybrid micro-/nanogels toward applications for optical sensing of pH, temperature, glucose, ions, and other species as well as for intracellular imaging. Due to their unique advantages, hybrid micro-/nanogels as optical probes are attracting substantial interests for continuous monitoring of chemical parameters in complex samples such as blood and bioreactor fluids, in chemical research and industry, and in food quality control. In particular, their intracellular probing ability enables the monitoring of the biochemistry and biophysics of live cells over time and space, thus contributing to the explanation of intricate biological processes and the development of novel diagnoses. Unlike most other probes, hybrid micro-/nanogels could also combine other multiple functions into a single probe. The rational design of hybrid micro-/nanogels will not only improve the probing applications as desirable, but also implement their applications in new arenas. With ongoing rapid advances in bionanotechnology, the well-designed hybrid micro-/nanogel probes will be able to provide simultaneous sensing, imaging diagnosis, and therapy toward clinical applications.

Hydrophilic fluorescent nanogel thermometer for intracellular thermometry

The first methodology to measure intracellular temperature is described. A highly hydrophilic fluorescent nanogel thermometer developed for this purpose stays in the cytoplasm and emits stronger fluorescence at a higher temperature. Thus, intracellular temperature variations associated with biological processes can be monitored by this novel thermometer with a temperature resolution of better than 0.5 degrees C.

Microcalorimetric investigation on metabolic activity and effects of La (III) in mitochondria isolated from indica rice 9311

Thermogenic metabolic curves were determined by the ampoule method at 303 K using a TAM air isothermal microcalorimeter in mitochondria isolated from rice 9311 (Oryza sativa L). From the thermogenic curves the activity recovery rate constant k and the maximum heat power Pm were obtained. Both were positively correlated to the protein content of rice mitochondria. The corresponding correlation coefficients were 0.9959 and 0.9950, respectively, indicating that the in vitro metabolic activity of mitochondria can be reliably expressed by these parameters. Addition of La (III) ions in concentrations ranging from 0 to 130 microg/mL resulted in significantly higher k and Pm values. Concentrations from 140 to 180 microg/mL had the opposite effect. These results are consistent with previous reports on the effects of rare earth elements on plant growth. We propose that the lanthanum-induced change of mitochondrial metabolic activity is a possible mechanism by which La (III) ions influence indica rice 9311 growth.

A microcalorimetric method for studying the biological effects of La(3+) on Escherichia coli

A microcalorimetric technique based on the bacterial heat-output was explored to evaluate the stimulatory effect of La(3+) on Escherichia coli. The power-time curves of the growth metabolism of E. coli and the effect of La(3+) on it were studied using an LKB-2277 BioActivity Monitor, stopped-flow method, at 37 degrees C. For evaluation of the results, the maximum power (P(max)), the growth rate constants (k) and the heat effects (Q(LOG), Q(STAT)) for the log phase, the stationary phase and the total heat effect (Q(T)) for E. coli were determined. The microcalorimetric method agreed with the conventional methods, such as cell numbers and biomass. La(3+) in the concentration ranges of 0-400 microg/ml has stimulatory effects on E. coli, while La(3+) ion of higher concentrations (>400 microg/ml) can inhibit the growth. This phenomenon is very similar to those observed from the in vitro cells and tissues from animals, plants and some microorganisms by other methods.

Microcalorimetric measurements carried out on isolated tumorous and nontumorous tissue samples from organs in the urogenital tract in comparison to histological and impulse-cytophotometric investigations

In this comparative study, microcalorimetric measurements were carried out on a total of 96 tumorous and nontumorous tissue samples taken from organs of the urogenital tract using a thermal activity monitor (TAM). Changes in the heat emission of the tissue samples were measured at 1-min intervals and graphically displayed as a function of time. The aim of the study was to compare the microcalorimetric results with impulse-cytophotometric and histological findings and provide evidence for the metabolic activity of tumorous and nontumorous tissue. In order to obtain the variation in metabolic activity, the maxima (Pmax) of the curves were determined as a value of the maximum thermal power of a tissue sample, the mean values (P) were determined by the mean thermal power and the contour integrals (W) were defined by the behavior of the energy reserves and their mobilization. The first part of the study was carried out to investigate whether tumorous and nontumorous tissue samples differ in general according to their metabolic activity. We discovered, using the parameters described above, that in general tumorous tissue exhibited a higher metabolic activity than nontumorous tissue samples. For example, both W and P in tumorous prostate tissue samples were eightfold higher and the (Pmax) value was 8.4-fold higher than in normal tissue. Additional investigations on testicle and kidney tissues were performed to find a possible correlation between microcalorimetric results and histological grading. We found that an increasing malignancy correlated with a higher metabolic activity of the tissue. Based upon these results we were able to differentiate the various histological gradings of these tumorous tissues by microcalorimetric measurements. The results show it is possible to differentiate between normal and tumorous tissue samples by microcalorimetric measurement based on the distinctly higher metabolic activity of malignant tissue. Furthermore, microcalorimetry allows a differentiation and classification of tissue samples into their histological grading. With the help of microcalorimetry, it might be possible in future to detect and record the metabolic processes of isolated tissue structures and changes in these activities as a result of medical intervention such as cytostatic treatment.