Bragg Curve Detection of Low-Energy Protons by Radiophotoluminescence Imaging in Lithium Fluoride Thin Films.

Lithium fluoride (LiF) crystals and thin films are utilized as radiation detectors for energy diagnostics of proton beams. This is achieved by analyzing the Bragg curves in LiF obtained by imaging the radiophotoluminescence of color centers created by protons. In LiF crystals, the Bragg peak depth increases superlinearly with the particle energy. A previous study has shown that, when 35 MeV protons impinge at grazing incidence onto LiF films deposited on Si(100) substrates, the Bragg peak in the films is located at the depth where it would be found in Si rather than in LiF due to multiple Coulomb scattering. In this paper, Monte Carlo simulations of proton irradiations in the 1-8 MeV energy range are performed and compared to experimental Bragg curves in optically transparent LiF films on Si(100) substrates. Our study focuses on this energy range because, as energy increases, the Bragg peak gradually shifts from the depth in LiF to that in Si. The impact of grazing incidence angle, LiF packing density, and film thickness on shaping the Bragg curve in the film is examined. At energies higher than 8 MeV, all these quantities must be considered, although the effect of packing density plays a minor role.

In Vivo Radiobiological Investigations with the TOP-IMPLART Proton Beam on a Medulloblastoma Mouse Model.

Protons are now increasingly used to treat pediatric medulloblastoma (MB) patients. We designed and characterized a setup to deliver proton beams for in vivo radiobiology experiments at a TOP-IMPLART facility, a prototype of a proton-therapy linear accelerator developed at the ENEA Frascati Research Center, with the goal of assessing the feasibility of TOP-IMPLART for small animal proton therapy research. Mice bearing Sonic-Hedgehog (Shh)-dependent MB in the flank were irradiated with protons to test whether irradiation could be restricted to a specific depth in the tumor tissue and to compare apoptosis induced by the same dose of protons or photons. In addition, the brains of neonatal mice at postnatal day 5 (P5), representing a very small target, were irradiated with 6 Gy of protons with two different collimated Spread-Out Bragg Peaks (SOBPs). Apoptosis was visualized by immunohistochemistry for the apoptotic marker caspase-3-activated, and quantified by Western blot. Our findings proved that protons could be delivered to the upper part while sparing the deepest part of MB. In addition, a comparison of the effectiveness of protons and photons revealed a very similar increase in the expression of cleaved caspase-3. Finally, by using a very small target, the brain of P5-neonatal mice, we demonstrated that the proton irradiation field reached the desired depth in brain tissue. Using the TOP-IMPLART accelerator we established setup and procedures for proton irradiation, suitable for translational preclinical studies. This is the first example of in vivo experiments performed with a "full-linac" proton-therapy accelerator.

Open Issues and Practical Suggestions for Telemedicine in Chronic Pain.

Telemedicine represents a major opportunity to facilitate continued assistance for patients with chronic pain and improve their access to care. Preliminary data show that an improvement can be expected of the monitoring, treatment adherence, assessment of treatment effect including the emotional distress associated with pain. Moreover, this approach seems to be convenient and cost-effective, and particularly suitable for personalized treatment. Nevertheless, several open issues must be highlighted such as identification of assessment tools, implementation of monitoring instruments, and ability to evaluate personal needs and expectations. Open questions exist, such as how to evaluate the need for medical intervention and interventional procedures, and how to define when a clinical examination is required for certain conditions. In this context, it is necessary to establish dynamic protocols that provide the right balance between face-to-face visits and telemedicine. Useful tips are provided to start an efficient experience. More data are needed to develop precise operating procedures. In the meantime, the first experiences from such settings can pave the way to initiate effective care pathways in chronic pain.

Evaluation of the impact of vitrification on the actin cytoskeleton of in vitro matured ovine oocytes by means of Raman microspectroscopy.

PURPOSE: Investigation of the changes induced by vitrification on the cortical F-actin of in vitro matured ovine oocytes by Raman microspectroscopy (RMS). METHODS: Cumulus-oocyte complexes, recovered from the ovaries of slaughtered sheep, were matured in vitro and vitrified following the Minimum Essential Volume method using cryotops. The cortical region of metaphase II (MII) oocytes (1) exposed to vitrification solutions but not cryopreserved (CPA-exp), (2) vitrified/warmed (VITRI), and (3) untreated (CTR) was analyzed by RMS. A chemical map of one quadrant of single CPA-exp, VITRI and CTR oocytes was, also, performed. In order to identify the region of Raman spectra representative of the cortical F-actin modification, a group of in vitro matured oocytes were incubated with latrunculin-A (LATA), a specific F-actin destabilizing drug, and processed for RMS analysis. Thereafter, all the oocytes were stained with rhodamine phalloidin and evaluated by fluorescence confocal microscopy. Raman spectra of the oocytes were, statistically, analyzed using Principal Component Analysis (PCA). RESULTS: The PCA score plots showed a marked discrimination between CTR oocytes and CPA-exp/ VITRI groups. The main differences, highlighted by PCA loadings, were referable to proteins (1657, 1440 and 1300 cm(-1)) and, as indicated by LATA experiments, also included the changes of the F-actin. Analysis by confocal microscopy revealed a clear alteration of the cortical F-actin of CPA-exp and VITRI oocytes confirming RMS results. CONCLUSIONS: Raman microspectroscopy may represent an alternative analytical tool for investigating the biochemical modification of the oocyte cortex, including the F-actin cytoskeleton, during vitrification of in vitro matured ovine oocytes.

Raman spectroscopy-based approach to detect aging-related oxidative damage in the mouse oocyte.

PURPOSE: Detection of chemical modifications induced by aging-related oxidative damage in mouse metaphase II (MII) oocytes by Raman microspectroscopy. METHODS: CD-1 mice at the age of 4-8 weeks (young mice) and 48-52 weeks (old mice), were superovulated and oocytes at metaphase II stage were recovered from oviducts. MII oocytes from young animals were divided into three groups: A) young oocytes, processed immediately after collection; B) in vitro aged oocytes, cultured in vitro for 10 h before processing; C) oxidative-stressed oocytes, exposed to 10 mM hydrogen peroxide for 2 min before processing. Oocytes from reproductively old mice were referred to as old oocytes (D). All the oocytes were analyzed by confocal Raman microspectroscopy. The spectra were statistically analyzed using Principal Component Analysis (PCA). RESULTS: PCA evidenced that spectra from young oocytes (A) were clearly distinguishable from those obtained from in vitro-aged, oxidative-damaged and old oocytes (B, C, D) and presented significant differences in the bands attributable to lipid components (C = C stretching, 1,659 cm⁻¹; CH2 bending, 1,450 cm⁻¹; CH3 deformation,1,345 cm⁻¹; OH bending, C-N stretching, 1,211 cm⁻¹) and protein components (amide I band,1,659 cm⁻¹; CH2 bending modes and CH3 deformation, 1,450 cm⁻¹; C-N and C-C stretching vibrations, 1,132 cm⁻¹; phenylalanine's vibration, 1,035 cm⁻¹) CONCLUSIONS: Raman spectroscopy is a valuable non-invasive tool for the identification of biochemical markers of oxidative damage and could represent a highly informative method of investigation to evaluate the oocyte quality.

Combining top-down and bottom-up routes for fabrication of mesoporous titania films containing ceria nanoparticles for free radical scavenging.

Nanocomposite thin films formed by mesoporous titania layers loaded with ceria nanoparticles have been obtained by combining bottom-up self-assembly synthesis of a titania matrix with top-down hard X-ray lithography of nanocrystalline cerium oxide. At first the titania mesopores have been impregnated with the ceria precursor solution and then exposed to hard X-rays, which triggered the formation of crystalline cerium oxides within the pores inducing the in situ growth of nanoparticles with average size of 4 nm. It has been observed that the type of coordinating agent in the solution plays a primary role in the formation of nanoparticles. Different patterns have been also produced through deep X-ray lithography by spatially controlling the nanoparticle growth on the micrometer scale. The radical scavenging role of the nanocomposite films has been tested using as a benchmark the UV photodegradation of rhodamine 6G. After impregnation with a rhodamine 6G solution, samples with and without ceria have shown a remarkably different response upon exposure to UV light. The dye photodegradation on the surface of nanocomposite films appears strongly slowed down because of the antioxidation effect of ceria nanoparticles.

The production of concentrated dispersions of few-layer graphene by the direct exfoliation of graphite in organosilanes.

We report the formation and characterization of graphene dispersions in two organosilanes, 3-glycidoxypropyl trimethoxysilane (GPTMS) and phenyl triethoxysilane (PhTES) as new reactive solvents. The preparation method was mild and easy and does not produce any chemical modification. The dispersions, which exhibit the Tyndall effect, were characterized by TEM and Raman spectroscopy to confirm the presence of few-layer graphene. Concentrations as high as 0.66 and 8.00 mg/ml were found for PhTES and GPTMS, respectively. The latter is one of the highest values reported for a dispersion of graphene obtained by any method. This finding paves the way for the direct synthesis of polymer nanofiller-containing composites consisting of graphene and reactive silanes to be used in sol-gel synthesis, without any need for solvent removal, thus preventing graphene reaggregation to form graphite flakes.

Development of novel cationic chitosan-and anionic alginate-coated poly(D,L-lactide-co-glycolide) nanoparticles for controlled release and light protection of resveratrol.

BACKGROUND: Resveratrol, like other natural polyphenols, is an extremely photosensitive compound with low chemical stability, which limits the therapeutic application of its beneficial effects. The development of innovative formulation strategies, able to overcome physicochemical and pharmacokinetic limitations of this compound, may be achieved via suitable carriers able to associate controlled release and protection. In this context, nanotechnology is proving to be a powerful strategy. In this study, we developed novel cationic chitosan (CS)- and anionic alginate (Alg)-coated poly(d,l-lactide-co-glycolide) nanoparticles (NPs) loaded with the bioactive polyphenolic trans-(E)-resveratrol (RSV) for biomedical applications. METHODS: NPs were prepared by the nanoprecipitation method and characterized in terms of morphology, size and zeta potential, encapsulation efficiency, Raman spectroscopy, swelling properties, differential scanning calorimetry, and in vitro release studies. The protective effect of the nanosystems under the light-stressed RSV and long-term stability were investigated. RESULTS: NPs turned out to be spherical in shape, with size ranging from 135 to about 580 nm, depending on the composition and the amount of polyelectrolytes, while the encapsulation efficiencies increased from 8% of uncoated poly(d,l-lactide-co-glycolide) (PLGA) to 23% and 32% of Alg- and CS-coated PLGA NPs, respectively. All nanocarriers are characterized by a biphasic release pattern, and more effective controlled release rates are obtained for NPs formulated with higher polyelectrolyte concentrations. Stability studies revealed that encapsulation provides significant protection against light-exposure degradation, by reducing the trans-cis photoisomerization reaction. Moreover, the nanosystems are able to prevent the degradation of trans isoform and the leakage of RSV from the carrier for a period of 6 months. CONCLUSION: Our findings indicated that the newly developed CS- and Alg-coated PLGA NPs are suitable to be used for the delivery of bioactive RSV. The encapsulation of RSV into optimized polymeric NPs provides improved drug loading, effective controlled release, and protection against light-exposure degradation, thus opening new perspectives for the delivery of bioactive related phytochemicals to be used for (nano)chemoprevention/chemotherapy.

FTIR nanobiosensors for Escherichia coli detection.

Infections due to enterohaemorrhagic E. coli (Escherichia coli) have a low incidence but can have severe and sometimes fatal health consequences, and thus represent some of the most serious diseases due to the contamination of water and food. New, fast and simple devices that monitor these pathogens are necessary to improve the safety of our food supply chain. In this work we report on mesoporous titania thin-film substrates as sensors to detect E. coli O157:H7. Titania films treated with APTES ((3-aminopropyl)triethoxysilane) and GA (glutaraldehyde) were functionalized with specific antibodies and the absorption properties monitored. The film-based biosensors showed a detection limit for E. coli of 1 × 10(2) CFU/mL, constituting a simple and selective method for the effective screening of water samples.

Release of ceria nanoparticles grafted on hybrid organic-inorganic films for biomedical application.

The controlled release of nanoparticles from a hybrid organic-inorganic surface allows for developing several applications based on a slow delivery of oxygen scavengers into specific environments. We have successfully grafted ceria nanoparticles on a hybrid film surface and tested their release in a buffer solution; the tests have shown that the particles are continuously delivered within a time scale of hours. The hybrid film has been synthesized using 3-glycidoxypropyltrimethoxysilane as precursor alkoxide; the synthesis has been performed in highly basic conditions to control the polycondensation reactions of both organic and inorganic networks via controlled aging of the solution. Only films prepared from aged solutions are able to graft ceria nanoparticles on their surface. The ceria nanoparticles have been characterized by X-ray diffraction, transmission electron microscopy and UV-vis spectroscopy, the hybrid films have been analyzed by Fourier transform infrared spectroscopy, atomic force microscopy and Raman spectroscopy. Raman imaging has been used for the release test. The hybrid film-ceria nanoparticles system fulfils the requirements of optical transparency and stability in buffer solutions which are necessary for biomedical applications.

Hybrid materials with an increased resistance to hard X-rays using fullerenes as radical sponges.

The protection of organic and hybrid organic-inorganic materials from X-ray damage is a fundamental technological issue for broadening the range of applications of these materials. In the present article it is shown that doping hybrid films with fullerenes C(60) gives a significant reduction of damage upon exposure to hard X-rays generated by a synchrotron source. At low X-ray dose the fullerene molecules act as `radical scavengers', considerably reducing the degradation of organic species triggered by radical formation. At higher doses the gradual hydroxylation of the fullerenes converts C(60) into fullerol and a bleaching of the radical sinking properties is observed.

Raman microspectroscopy as a non-invasive tool to assess the vitrification-induced changes of ovine oocyte zona pellucida.

Cryopreservation-induced modifications of zona pellucida (ZP) have been explored to a lesser extent compared to other oocyte compartments. Different methods have been applied to identify ZP changes, but most of them are invasive and measure only few properties of ZP. Raman microspectroscopy (RMS) is a powerful technique for studying the molecular composition of cells but to date few studies have been performed on the oocytes using this method. The aim of the present study is to investigate the structural modifications of ZP of vitrified/warmed in vitro matured ovine oocytes by means of RMS. Cumulus-oocyte complexes were recovered from the ovaries of slaughtered adult sheep, matured in vitro and vitrified following the Minimum Essential Volume method using cryotops. ZPs of vitrified/warmed oocytes (VITRI), were exposed to vitrification solutions but not cryopreserved (CPA-exp) and untreated oocytes (CTR) were analyzed by RMS. We focused our analysis on the ZP protein and carbohydrate components by analyzing the 1230-1300 cm(-1) amide III region and the 1020-1140 cm(-1) spectral range in RMS spectra, respectively. The spectral profiles in the ranges of proteins and carbohydrates were comparable between CTR and CPA-exp ZPs, whereas VITRI ZPs showed a significantly altered protein secondary structure characterized by an increase in ß-sheet content and a decrease in the α-helix content. A significant modification of the carbohydrate components was also observed. This study demonstrates that vitrification of ovine oocytes induces biochemical changes of ZP related to the secondary structure of proteins and carbohydrate residues. Cryoprotectants do not strongly alter the molecular composition of ZP which is affected mainly by cooling. Raman technology offers a powerful and non-invasive tool to assess molecular modifications induced by cryopreservation in oocytes.

Nanocomposite mesoporous ordered films for lab-on-chip intrinsic surface enhanced Raman scattering detection.

Mesoporous nanocomposite materials have been fabricated through integration of evaporation-induced self-assembly and deep X-ray lithography. Micropatterned films made using a mesoporous ordered silica matrix which contains silver nanoparticles have been obtained. The exposure of the mesoporous films to high energy X-rays, which are generated by a synchrotron source, produces several effects: the removal of the surfactant, the densification of the silica backbone and the formation of silver nanoparticles. This integrated process produces a nanocomposite material which has a 2D-hexagonal organized porosity and silver nanoparticles with a sharp size distribution around 5 nm. The patterned nanostructured films have been tested as a lab-on-chip device for intrinsic surface enhanced Raman scattering detection using a solution containing rhodamine 6G in ethanol and measuring Raman response as a function of laser power.

Innovative composite films of chitosan, methylcellulose, and nanoparticles.

Plastic is readily available and inexpensive, so it is becoming the main material for packaging. Unfortunately plastics do not biodegrade and, if reduced in small pieces, contaminate soil and waterways. In the present work, natural films composed of chitosan, methylcellulose, and silica (SiO(2)) nanoparticles (NPs) were developed as new packaging materials. The effect of the incorporation of NPs into the polymeric film matrix was evaluated. An excellent improvement of the mechanical properties was obtained for nanostructured films with a composition of CH:MC 50:50 and NPs 1% w/v that make these materials able to replace plastics and derivatives, reducing environmental pollution.

Structural evolution during evaporation of a 3-glycidoxypropyltrimethoxysilane film studied in situ by time resolved infrared spectroscopy.

Time resolved infrared spectroscopy has been applied to study in situ the evaporation process of a 3-glycidoxypropyltrimethoxysilane hybrid sol by casting a droplet on a ZnSe substrate; the analysis has been performed in the middle-infrared range and in the near-infrared range. The experiment has allowed following the structural changes induced by water evaporation and the formation of ordered structures within the cast film; the CH(2) scissoring bands have been used as a fingerprint for the disorder to order transition of the hybrid. The experiment has been done using both a fresh sol and an aged sol which produce respectively an amorphous material and a crystalline hybrid material. The analysis has shown that the epoxy groups do not react during the evaporation while the silica structure shows only a slight condensation and an increase in open cage-like species. At the end of evaporation the hybrid has a "soft-like" state which allows structural rearrangements to self-order.

Chemical tailoring of hybrid sol-gel thick coatings as hosting matrix for functional patterned microstructures.

A phenyl-based hybrid organic - inorganic coating has been synthesized and processed by hard X-ray lithography. The overall lithography process is performed in a two-step process only (X-rays exposure and chemical etching). The patterns present high aspect ratio, sharp edges, and high homogeneity. The coating has been doped with a variety of polycyclic aromatic hydrocarbon functional molecules, such as anthracene, pentacene, and fullerene. For the first time, hard X-rays have been combined with thick hybrid functional coatings, using the sol-gel thick film directly as resist. A new technique based on a new material combined with hard X-rays is now available to fabricate optical devices. The effect due to the high-energy photon exposure has been investigated using FT-IR and Raman spectroscopy, laser scanner, optical profilometer, and confocal and electron microscope. High-quality thick hybrid fullerene-doped microstructures have been fabricated.

Tracking infrared signatures of drugs in cancer cells by Fourier transform microspectroscopy.

Aimed at developing accurate, reliable and cost-saving analytical techniques for drugs screening we evaluated the potential of Fourier Transform (FT) InfraRed (IR) microspectroscopy (microFTIR) as a quantitative pre-diagnostic approach for the rapid identification of IR signatures of drugs targeting specific molecular pathways causing Chronic Myeloid Leukemia (CML). To obtain reproducible FTIR absorbance spectra at the necessary spatial resolution we optimized sample preparation and acquisition parameters on a single channel Mercury-Cadmium-Telluride (MCT) detector in the spectral interval of frequencies from 4000 to 800 cm(-1). Single K562 cells were illuminated by Synchrotron Radiation (SR) and a number of ~15 K562 cells spread in monolayer were illuminated by a conventional IR source (Globar), respectively. Combining IR spectral data with the results of complementary biochemical investigations carried out in samples by different analytical methods we identified and cross-validated IR signatures of drugs targeting the oncogenic protein BCR/ABL and its associated abnormal tyrosine kinase activity in K562 cell line. Unsupervised pattern recognition performed by Hierarchical Cluster Analysis (HCA) clustered the spectra of single K562 cells in two distinct groups roughly corresponding to living and to apoptotic cells, respectively. The corresponding IR spectral profiles were assumed to represent drug-resistant and drug-sensitive cells. Significant variations with increasing percentages of apoptotic cells were observed after the treatment of K562 cells with drugs that directly or indirectly target BCR/ABL. In conclusion, we suggest that microFTIR associated with multivariate data analysis may be useful to assess drug compounds in ex vivo cancer cell models and possibly peripheral blast cells from CML patients.

Evaporation-induced crystallization of pluronic F127 studied in situ by time-resolved infrared spectroscopy.

Rapid scan time-resolved infrared spectroscopy has been used to study in situ the crystallization induced by evaporation in an aqueous solution of a triblock copolymer, Pluronic F127. A droplet of the solution was cast on a silicon substrate and the evaporation followed by an infrared microscope in transmission mode. The evaporation rate of water, in the last stage of the process, has been shown to be correlated to the changes in the block copolymer; four different stages can be distinguished. The block copolymer passes from an amorphous micellar state in water to a partially crystallized phase in well-defined stages of the evaporation; the complete change from amorphous to crystalline state of Pluronic F127 is observed only after all water is evaporated.

Facing the challenge of biosample imaging by FTIR with a synchrotron radiation source.

Fourier-transform infrared (FTIR) synchrotron radiation (SR) microspectroscopy is a powerful molecular probe of biological samples at cellular resolution (<10 microm). As the brilliance of SR is 100-1000 times higher than that of a conventional Globar source, FTIR microscopes are now available in almost all advanced SR facilities around the world. However, in spite of this superior performance, the expected advances in IR SR microscopy have not yet been realised, particularly with regard to bio-analytical studies of single cells and soft tissues. In recent decades solid-state array detectors have revolutionized the fields of molecular spectroscopy and chemical imaging, and now new IR focal plane array detectors implemented at ultra-bright SR facilities will extend the performance and overcome the existing limitations, possibly allowing IR SR instrumentation to achieve the highest sensitivity and resolution of molecular imaging. The impact of IR imaging on large tissue area and the complexity of the analysis are discussed. In view of the high brilliance of SR sources, a comparison of published microscope images is given. Finally, it is briefly outlined how an optimized combination of IR instrumentation and SR optical systems could reach the expected advantages of a SR-based FTIR imaging system.