Copper Complexes with 1,10-Phenanthroline Derivatives: Underlying Factors Affecting Their Cytotoxicity.

The interpretation of in vitro cytotoxicity data of Cu(II)-1,10-phenanthroline (phen) complexes normally does not take into account the speciation that complexes undergo in cell incubation media and its implications in cellular uptake and mechanisms of action. We synthesize and test the activity of several distinct Cu(II)-phen compounds; up to 24 h of incubation, the cytotoxic activity differs for the Cu complexes and the corresponding free ligands, but for longer incubation times (e.g., 72 h), all compounds display similar activity. Combining the use of several spectroscopic, spectrometric, and electrochemical techniques, the speciation of Cu-phen compounds in cell incubation media is evaluated, indicating that the originally added complex almost totally decomposed and that Cu(II) and phen are mainly bound to bovine serum albumin. Several methods are used to disclose relationships between structure, activity, speciation in incubation media, cellular uptake, distribution of Cu in cells, and cytotoxicity. Contrary to what is reported in most studies, we conclude that interaction with cell components and cell death involves the separate action of Cu ions and phen molecules, not [Cu(phen)n] species. This conclusion should similarly apply to many other Cu-ligand systems reported to date.

High Efficacy of Ozonated Oils on the Removal of Biofilms Produced by Methicillin-Resistant Staphylococcus aureus (MRSA) from Infected Diabetic Foot Ulcers.

Ozone has a high wound healing capacity and antibacterial properties and can be used as a complementary treatment in infections. Methicillin-resistant S. aureus (MRSA) is the most common pathogen found in infected diabetic foot ulcers. Most of MRSA are resistant to several classes of antibiotics and, therefore, there is a need for new, effective, and well-tolerated agents. Thus, we aimed evaluate the antimicrobial and antibiofilm potentials of ozonated vegetable oils against MRSA strains isolated from diabetic foot ulcers. Six ozonated oils were produced with concentrations of ozone ranging from 0.53 to 17 mg of ozone/g of oil. The peroxide values were determined for each oil. Ozonated oils content on fatty acid was determined by gas chromatography equipped with a flame ionization detector. The antimicrobial susceptibility testing was performed by the Kirby-Bauer disk diffusion method and the effect of ozonated oils on biofilm formation ability and on established biofilms was investigated. In general, the content in identified unsaturated fatty acid in oils decreased with the increase of ozonation time and, consequently, the peroxide value increased. Most bacterial strains were inhibited by ozonated oil at a concentration of 4.24 mg/g. Ozonated oils had moderate to high ability to remove adhered cells and showed a high capacity to eradicate 24 h old biofilms. Our results show promising use of ozonated oils on the treatment of infections, in particular those caused by multidrug-resistant MRSA strains.

Subproteomic signature comparison of in vitro selected fluoroquinolone resistance and ciprofloxacin stress in Salmonella Typhimurium DT104B.

BACKGROUND: Fluoroquinolone resistance in nontyphoidal Salmonella is a situation of serious and international concern, particularly in S. Typhimurium DT104B multiresistant strains. Although known to be multifactorial, fluoroquinolone resistance is still far from a complete understanding. METHODS: Subproteome changes between an experimentally selected fluoroquinolone-resistant strain (Se6-M) and its parent strain (Se6), and also in Se6-M under ciprofloxacin (CIP) stress, were evaluated in order to give new insights into the mechanisms involved. Proteomes were compared at the intracellular and membrane levels by a 2-DE~LC-MS/MS and a shotgun LC-MS/MS approach, respectively. RESULTS: In total, 35 differentially abundant proteins were identified when comparing Se6 with Se6-M (25 more abundant in Se6 and 10 more abundant in Se6-M) and 82 were identified between Se6-M and Se6-M+CIP (51 more abundant in Se6-M and 31 more abundant under ciprofloxacin stress). CONCLUSION: Several proteins with known and possible roles in quinolone resistance were identified which provide important information about mechanism-related differential protein expression, supporting the current knowledge and also leading to new testable hypotheses on the mechanism of action of fluoroquinolone drugs.

A new 3,5-bisporphyrinylpyridine derivative as a fluorescent ratiometric probe for zinc ions.

A new 3,5-disubstituted pyridine with two porphyrin moieties was prepared through an efficient synthetic approach involving 2-formyl-5,10,15,20-tetraphenylporphyrin (1), piperidine, and catalytic amounts of [La(OTf)3]. 3,5-Bis(5,10,15,20-tetraphenylporphyrin-2-ylmethyl)pyridine (2) was fully characterized and its sensing ability towards Zn(2+), Cu(2+), Hg(2+), Cd(2+), and Ag(+) was evaluated in solution by absorption and fluorescence spectroscopy and in gas phase by using matrix-assisted laser desorption/ionization (MALDI)-TOF mass spectrometry. Strong changes in the ground and excited state were detected in the case of the soft metal ions Zn(2+), Cd(2+), Hg(2+), and Cu(2+). A three-metal-per-ligand molar ratio was obtained in all cases and a significant ratiometric behavior was observed in the presence of Zn(2+) with the appearance of a new band at 608 nm, which can be assigned to a metal-to-ligand charge transfer. The system was able to quantify 79 ppb of Zn(2+) and the theoretical calculations are in accordance with the stoichiometry observed in solution. The gas-phase sensorial ability of compound 2 towards all metal ions was confirmed by using MALDI-TOF MS and in solid state by using polymeric films of polymethylmethacrylate (PMMA) doped with ligand 2. The results showed that compound 2 can be analytically used to develop new colorimetric molecular devices that are able to discriminate between Hg(2+) and Zn(2+) in solid phase. The crystal structure of Zn(II) complex of 3,5-bisporphyrinylpyridine was unequivocally elucidated by using single-crystal X-ray diffraction studies.

Synthesis, spectroscopy studies, and theoretical calculations of new fluorescent probes based on pyrazole containing porphyrins for Zn(II), Cd(II), and Hg(II) optical detection.

New pyrazole-porphyrin conjugates were successfully prepared from a reaction of ß-porphyrin-chalcone derivatives with phenylhydrazine in acetic acid followed by an oxidative step. This fast and efficient synthetic approach provided the expected compounds in yields up to 82%. The sensing ability of the new porphyrin-pyrazole derivatives to detect the metal ions Ag(+), Na(+), K(+), Mg(2+), Ca(2+), Ni(2+), Cu(2+), Zn(2+), Cd(2+), Hg(2+), Pb(2+), and Cr(3+) was studied by spectrophotometric and spectrofluorimetric titrations. In the presence of Zn(2+), the conjugates exhibit changes in the emission spectra that are desired for a ratiometric-type fluoroionophoric detection probe. The studies were extended to gas phase, where the pyrazole-porphyrin conjugates show ability to sense metal ions with high selectivity toward Cu(2+) and Ag(+), and in poly(methyl methacrylate) doped films with promising results for Zn(2+) detection.

Complete proteome of a quinolone-resistant Salmonella Typhimurium phage type DT104B clinical strain.

Salmonellosis is one of the most common and widely distributed foodborne diseases. The emergence of Salmonella strains that are resistant to a variety of antimicrobials is a serious global public health concern. Salmonella enterica serovar Typhimurium definitive phage type 104 (DT104) is one of these emerging epidemic multidrug resistant strains. Here we collate information from the diverse and comprehensive range of experiments on Salmonella proteomes that have been published. We then present a new study of the proteome of the quinolone-resistant Se20 strain (phage type DT104B), recovered after ciprofloxacin treatment and compared it to the proteome of reference strain SL1344. A total of 186 and 219 protein spots were recovered from Se20 and SL1344 protein extracts, respectively, after two-dimensional gel electrophoresis. The signatures of 94% of the protein spots were successfully identified through matrix-assisted laser desorption/ionization mass spectrometry (MALDI-TOF MS). Three antimicrobial resistance related proteins, whose genes were previously detected by polymerase chain reaction (PCR), were identified in the clinical strain. The presence of these proteins, dihydropteroate synthase type-2 (sul2 gene), aminoglycoside resistance protein A (strA gene) and aminoglycoside 6'-N-acetyltransferase type Ib-cr4 (aac(6')-Ib-cr4 gene), was confirmed in the DT104B clinical strain. The aac(6')-Ib-cr4 gene is responsible for plasmid-mediated aminoglycoside and quinolone resistance. This is a preliminary analysis of the proteome of these two S. Typhimurium strains and further work is being developed to better understand how antimicrobial resistance is developing in this pathogen.

On-target ultrasonic digestion of proteins.

In the present work, we report a novel on-target protein cleavage method. The method utilizes ultrasonic energy and allows up to 20 samples to be cleaved in 5 min for protein identification and one sample in 30 s for on-tissue digestion. The standard proteins were spotted on a conductive glass slide in a volume of 0.5 µL followed by 5 min of ultrasonication after trypsin addition. Controls (5 min, 37°C no ultrasonication) were also assayed. After trypsin addition, digestion of the tissues was enhanced by 30 s of ultrasonication. The samples were analyzed and compared to those obtained by using conventional 3 h heating proteolysis. The low sample volume needed for the digestion and reduction in sample-handling steps and time are the features that make this method appealing to the many laboratories working with high-throughput sample treatment.

Bis(o-methylserotonin)-containing iridium(III) and ruthenium(II) complexes as new cellular imaging dyes: synthesis, applications, and photophysical and computational studies.

We report the synthesis, characterization, and scope of a new versatile emissive molecular probe functionalized with a 1,10-phenanthroline moiety containing methylserotonin groups as binding sites for metal ion recognition. The synthesis, characterization, and evaluation of the in vitro imaging capability of the iridium(III) and ruthenium(II) complexes [Ir(ppy)2(N-N)](+) and [Ru(bpy)2(N-N)](2+), in which ppy is 2-phenylpyridine, bpy is 2,2'-bipyridine, and N-N is a 1,10-phenanthroline ligand functionalized with two methylserotonin groups to serve as binding sites for metal ion recognition, is reported. The uptake of these compounds by living freshwater fish (Carassius auratus) was studied by fluorescence microscopy, and the cytotoxicity of ligand N-N and [Ru(bpy)2(N-N)](2+) in this species was also investigated.

Turn-on selective vitamin B6 derivative fluorescent probe for histidine detection in biological samples.

A new compound L soluble in water derived from vitamin B6 was successfully synthesized and characterized. The complex LAl(3+) is a turn-on selective fluorescent probe for histidine in HEPES buffer, with detection and quantification limits of 0.3 µM and 0.6 µM, respectively. The application of the complex LAl(3+) in real urine samples is reported.

Steady-state and time-resolved investigations on pyrene-based chemosensors.

Two novel fluorescent probes bearing a single (P) and two (a podand-like structure, L) pyrene units derived from 1,5-bis(2-aminophenoxy)-3-oxopentane have been synthesized and investigated in dioxane using UV-vis absorption, and steady-state and time-resolved (in a picosecond time scale) emission spectroscopy; in the gas phase, matrix-assisted laser desorption ionization mass spectrometry was employed. In dioxane, the absorption and emission spectra of P present a unique band with maxima at 361 and 392 nm, which have been associated with the monomer absorption and emission bands, respectively. In dioxane, for compound L, an additional band with a maximum at ∼525 nm is observed; upon the addition of water, an emissive band (with maxima varying from 405 to 490 nm) appears in both P and L spectra; this is discussed in terms of the emission of a species with charge character. Upon metal addition (Cu(2+), Zn(2+), and Ag(+)) to P, a gradual quenching effect of the monomer emission is observed and found to be more pronounced with Cu(2+). In the case of L, upon the addition of metal cations, the long emission band (∼550 nm) decreases and the monomer emission band increases (with an isoemissive point at ∼450 nm) and no evidence for the intermediate band (at ∼405-490 nm) now exists. Time-resolved data in dioxane/water mixtures showed that for P and L these two fit double- and triple-exponential decay laws, respectively. With P, this has been attributed to a two-state system, which involves the monomer and a charged species, with its emission maxima varying with the polarity of the media (here mirrored by its dielectric constant), which can potentially be addressed to an exciplex-like species, whereas with L, it has been attributed to a three-state system involving, in addition to these two species, an excimer. From absorption and fluorescence excitation and time-resolved data, evidence is given for the presence of intramolecular dimer formation in the ground state.

Pathway-guided monitoring of the disease course in bladder cancer with longitudinal urine proteomics.

BACKGROUND: Monitoring bladder cancer over time requires invasive and costly procedures. Less invasive approaches are required using readily available biological samples such as urine. In this study, we demonstrate a method for longitudinal analysis of the urine proteome to monitor the disease course in patients with bladder cancer. METHODS: We compared the urine proteomes of patients who experienced recurrence and/or progression (n = 13) with those who did not (n = 17). We identified differentially expressed proteins within various pathways related to the hallmarks of cancer. The variation of such pathways during the disease course was determined using our differential personal pathway index (dPPi) calculation, which could indicate disease progression and the need for medical intervention. RESULTS: Seven hallmark pathways are used to develop the dPPi. We demonstrate that we can successfully longitudinally monitor the disease course in bladder cancer patients through a combination of urine proteomic analysis and the dPPi calculation, over a period of 62 months. CONCLUSIONS: Using the information contained in the patient's urinary proteome, the dPPi reflects the individual's course of bladder cancer, and helps to optimise the use of more invasive procedures such as cystoscopy.

Bladder cancer must be closely monitored for progression, but this requires expensive and invasive procedures such as cystoscopy. Less invasive procedures using readily available samples such as urine are needed. Here, we present an approach that measures the levels of various proteins in the urine. We compare protein levels at different points during the disease course in patients with bladder cancer, and show this helps to flag disease recurrence and the need for medical intervention. Our approach could help clinicians to determine which patients require more invasive testing and treatment.

Novel emissive bio-inspired non-proteinogenic coumarin-alanine amino acid: fluorescent probe for polyfunctional systems.

Two new bio-inspired non-proteinogenic compounds L1 and L2, containing coumarin and/or acridine chromophores and bearing as spacer an alanine amino acid were successfully synthesized and fully characterized by elemental analysis, (1)H and (13)C NMR, infrared spectroscopy (KBr discs), melting point, ESI-TOF (electrospray ionization-time of flight-mass), UV-vis absorption and emission spectroscopy, fluorescence quantum yields and lifetime measurements. A relative fluorescence quantum yield of 0.02 was determined for both compounds. In L2 the presence of an intramolecular energy transfer from the coumarin to the acridine unit was observed. L1 and L2 are quite sensitive to the basicity of the environment. At alkaline values both compounds show a strong quenching in the fluorescence emission, attributed to the photoinduced electron transfer (PET). However, both deprotonated forms recover the emission with the addition of Zn(2+), Cd(2+) and Al(3+) metal ions. As multifunctional emissive probes, the titration of L1 and L2 with lanthanides (III), Eu(3+) and Tb(3+) was also explored as new visible bio-probes in the absence and in the presence of liposomes. In a liposomal environment a lower energy transfer was observed.

Nocturnal Birds of Prey as Carriers of Staphylococcus aureus and Other Staphylococci: Diversity, Antimicrobial Resistance and Clonal Lineages.

Owls are nocturnal predators that inhabit urbanized and farmlands. They are in direct contact with other animals, both livestock and small wild rodents that they mostly feed on. Staphylococci can be both commensal and pathogenic bacteria that are widespread across the various ecological niches. We aimed to isolate staphylococci from owls and to characterize their antimicrobial resistance, virulence factors and genetic lineages. Swab samples were collected from the throat and cloaca of 114 owls admitted to two rehabilitation centers in Portugal. The identification of staphylococci species was performed by MALDI-TOF. Staphylococci antimicrobial resistance and virulence genes were investigated by means of the disk diffusion method and PCR. Staphylococcus aureus isolates were characterized by MLST, agr and spa-typing. Of the tested animals, 66 isolates were recovered, including 10 different species of staphylococci, of which 25 were coagulase-positive (CoPS) and 41 were coagulase-negative (CoNS). Twenty-three S. aureus were isolated, of which one mecC-MRSA was identified. The isolates were mainly resistant to penicillin, aminoglycosides, clindamycin and tetracycline. mecC-MRSA belonged to ST1245 and spa-type t843 and the remaining S. aureus were ascribed to 12 STs and 15 spa types. A high diversity of clonal lineages was identified among the S. aureus isolated from wild owls. Owls feed mainly on small rodents often exposed to waste and anthropogenic sources, which may explain the moderate prevalence of S. aureus in these animals.

High Frequency of the EMRSA-15 Clone (ST22-MRSA-IV) in Hospital Wastewater.

Hospital wastewaters often carry multidrug-resistant bacteria and priority pathogens, such as methicillin-resistant Staphylococcus aureus (MRSA). Pathogens and antibiotic resistance genes present in wastewaters may reach the natural environment facilitating their spread. Thus, we aimed to isolate MRSA from wastewater of 3 hospitals located in the north of Portugal and to characterize the isolates regarding the antimicrobial resistance and genetic lineages. A total of 96 wastewater samples were collected over six months. The water was filtered, and the filtration membrane was immersed in BHI broth supplemented with 6.5% of NaCl and incubated. The inoculum was streaked in ORSAB agar plates for MRSA isolation. The isolates susceptibility testing was performed against 14 antimicrobial agents. The presence of resistance and virulence genes was accessed by PCR. Molecular typing was performed in all isolates. From the 96 samples, 28 (29.2%) were MRSA-positive. Most isolates had a multidrug-resistant profile and carried the mecA, blaZ, aac(6')-Ie-aph(2″)-Ia, aph(3')-IIIa, ermA, ermB, ermC, tetL, tetM, dfrA dfrG and catpC221 genes. Most of the isolates were ascribed to the immune evasion cluster (IEC) type B. The isolates belonged to ST22-IV, ST8-IV and ST105-II and spa-types t747, t1302, t19963, t6966, t020, t008 and tOur study shows that MRSA can be found over time in hospital wastewater. The wastewater treatment processes can reduce the MRSA load. The great majority of the isolates belonged to ST22 and spa-type t747 which suggests the fitness of these genetic lineages in hospital effluents.

Multidrug-Resistant Methicillin-Resistant Coagulase-Negative Staphylococci in Healthy Poultry Slaughtered for Human Consumption.

Coagulase-negative staphylococci are commensals that are known to be prevalent in most environments, and they are also an important reservoir of antimicrobial-resistant genes. Staphylococcal infections in animal husbandry are a high economic burden. Thus, we aimed to determine the prevalence and species diversity of methicillin-resistant coagulase-negative staphylococci (MRCoNS) in poultry slaughtered for human consumption and to study the antimicrobial resistance of the isolates. Swab samples were recovered from 220 commercial chickens, homebred chickens and quails. Species identification was performed using MALDI-TOF. Antimicrobial susceptibility testing was performed by the disc diffusion method against 14 antimicrobials. The presence of antimicrobial-resistant genes was investigated by polymerase chain reaction. Totals of 11 (19.6%), 13 (20.3%), and 51 (51%) MRCoNS were isolated from commercial chickens, homebred chickens and quails, respectively. S. lentus was isolated from all homebred chickens, whereas 11 S. lentus and 2 S. urealyticus were isolated from commercial chickens. As for quails, the most prevalent MRCoNS were S. urealyticus. Almost all isolates had a multidrug-resistant profile and carried the mecA gene. Most isolates showed resistance to erythromycin, clindamycin, penicillin, tetracycline, ciprofloxacin and fusidic acid and harbored the ermA, ermB, ermC, mphC tetK, tetL, tetM and tetO genes. This study showed a frequent occurrence of multidrug resistance in MRCoNS isolated from healthy poultry in Portugal.

A One Health Approach Molecular Analysis of Staphylococcus aureus Reveals Distinct Lineages in Isolates from Miranda Donkeys (Equus asinus) and Their Handlers.

Donkeys (Equus asinus) are in decline in Europe. Occupational exposure to farm animals has been associated with increased staphylococci carriage. We aimed to isolate S. aureus and coagulase-negative staphylococci (CoNS) from donkeys and handlers and characterize the antimicrobial resistance profiles and genetic lineages of S. aureus strains. Oral and nasal swab samples were collected from 49 Miranda donkeys and 23 handlers from 15 different farms. Staphylococci species were identified by MALDI-TOF MS. The presence of antimicrobial resistance genes and virulence factors was investigated by PCR. Molecular typing was performed in S. aureus isolates. From the 49 donkey samples, 4 S. aureus (8.2%) and 21 CoNS (42.9%) were isolated. Ten handlers (43.5%) were carriers of S. aureus and 4 (17.4%) carried CoNS. The CoNS isolates showed resistance to several classes of antimicrobials encoded by the mecA, aph (3')-IIIa, ant (4')-Ia, tetM, tetK, lnuA, ermB, ermC, dfrA and dfrG genes. S. aureus isolates were resistant to penicillin, aminoglicosides and tetracycline harboring the blaZ, aph (3')-IIIa, tetL, tetM and tetK genes. All S. aureus isolates from donkeys belonged to ST49 and spa-type t208 while the strains isolated from the handlers were ascribed to 3 STs and 7 spa-types. However, human isolates were from different STs than the donkey isolates. Donkeys are mainly colonized by methicillin-resistant S. sciuri. S. aureus transmission between donkeys and their handlers appears not to have occurred since the isolates belonged to different genetic lineages.

Bioinformatics study of expression from genomes of epidemiologically related MRSA CC398 isolates from human and wild animal samples.

One of the most important livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) genetic lineages is the clonal complex (CC) 398, which can cause typical S. aureus-associated infections in people. In this work, whole-genome sequencing, RNA-sequencing, and gel-based comparative proteomics were applied to study the genetic characteristics of three MRSA CC398 isolates recovered from humans (strains C5621 and C9017), and from an animal (strain OR418). Of the three strains, C9017 presented the broadest resistance genotype, including resistance to fluroquinolone, clindamycin, tiamulin, macrolide and aminoglycoside antimicrobial classes. The scn, sak, and chp genes of the immune evasion cluster system were solely detected in OR418. Pangenome analysis showed a total of 288 strain-specific genes, most of which are hypothetical or phage-related proteins. OR418 had the most pronounced genetic differences. RNAIII (δ-hemolysin) gene was clearly the most expressed gene in OR418 and C5621, but it was not detected in C9017. Significant differences in the proteome profiles were found between strains. For example, the immunoglobulin-binding protein Sbi was more abundant in OR418. Considering that Sbi is a multifunctional immune evasion factor in S. aureus, the results point to OR418 strain having high zoonotic potential. Overall, multiomics biomarker signatures can assume an important role to advance precision medicine in the years to come. SIGNIFICANCE: MRSA is one of the most representative drug-resistant pathogens and its dissemination is increasing due to MRSA capability of establishing new reservoirs. LA-MRSA is considered an emerging problem worldwide and CC398 is one of the most important genetic lineages. In this study, three MRSA CC398 isolates recovered from humans and from a wild animal were analyzed through whole-genome sequencing, RNA-sequencing, and gel-based comparative proteomics in order to gather systems-wide omics data and better understand the genetic characteristics of this lineage to identify distinctive markers and genomic features of relevance to public health.

Novel small stable gold nanoparticles bearing fluorescent cysteine-coumarin probes as new metal-modulated chemosensors.

Emissive molecular probes based on amino acid moieties are very appealing because of their application as new building blocks in peptide synthesis. Two new bioinspired coumarin probes (L1 and L2) were synthesized and fully characterized by elemental analysis, infrared, (1)H NMR, (13)C NMR, UV-vis absorption and emission spectroscopy, matrix-assisted laser desorption-ionization time-of-flight mass spectrometry (MALDI-TOF-MS), lifetime measurements, and X-ray crystal diffraction. Their sensing ability toward alkaline earth, transition, and post-transition metal ions (Ca(2+), Zn(2+), Cd(2+), Cu(2+), Ni(2+), Hg(2+), Ag(+), and Al(3+)) and their acid-base behavior (H(+), OH(-)) were explored in absolute ethanol by absorption and fluorescence spectroscopy. Compound L1 shows a strong complexation constant with the soft metal ions Zn(2+), Cd(2+), and Ag(+). Compound L2 shows a high fluorescence quantum yield, and it could be used as a non-pH-dependent fluorescent biological probe. Very small gold nanoparticles (AuNPs) using compounds L1 and L2 as stabilizers were obtained by using a reductive method and were characterized by UV-vis, light scattering, and transmission electron microscopy (TEM). Dynamic light scattering and TEM studies show that the formation of small nanoparticles is around 4.27 ± 0.64 nm for L1 and around 2.69 ± 0.96 nm for L2. The new stable Cou@AuNPs behaved as supramolecular chemosensors, which have been selective for the heavy element Hg(2+), with a concomitant change of color from pink to dark red/brown and an increase of size up to 100-fold.

Bioinspired systems for metal-ion sensing: new emissive peptide probes based on benzo[d]oxazole derivatives and their gold and silica nanoparticles.

Seven new bioinspired chemosensors (2-4 and 7-10) based on fluorescent peptides were synthesized and characterized by elemental analysis, (1)H and (13)C NMR, melting point, matrix-assisted laser desorption-ionization time-of-flight mass spectrometry (MALDI-TOF-MS), and IR and UV-vis absorption and emission spectroscopy. The interaction with transition- and post-transition-metal ions (Cu(2+), Ni(2+), Ag(+), Zn(2+), Cd(2+), Hg(2+), Pb(2+), and Fe(3+)) has been explored by absorption and fluorescence emission spectroscopy and MALDI-TOF-MS. The reported fluorescent peptide systems, introducing biological molecules in the skeleton of the probes, enhance their sensitivity and confer them strong potential for applications in biological fields. Gold and silica nanoparticles functionalized with these peptides were also obtained. All nanoparticles were characterized by dynamic light scattering, transmission electron microscopy, and UV-vis absorption and fluorescence spectroscopy. Stable gold nanoparticles (diameter 2-10 nm) bearing ligands 1 and 4 were obtained by common reductive synthesis. Commercial silica nanoparticles were decorated at their surface using compounds 8-10, linked through a silane spacer. The same chemosensors were also taken into aqueous solutions through their dispersion in the outer layer of silica core/poly(ethylene glycol) shell nanoparticles. In both cases, these complex nanoarchitectures behaved as new sensitive materials for Ag(+) and Hg(2+) in water. The possibility of using these species in this solvent is particularly valuable because the impact on human health of heavy- and transition-metal-ion pollution is very severe, and all analytical and diagnostics investigations involve a water environment.

Light and colour as analytical detection tools: a journey into the periodic table using polyamines to bio-inspired systems as chemosensors.

This critical review describes some developments on the chemistry of fluorescent and colorimetric molecular probes or chemosensors, based on polyamines and associated compounds having oxygen and/or sulfur as donor atoms. The reported systems are essentially based on some selected published work in this field in the last five years, and in the work developed by the authors from 2000 onwards. Some interesting properties beyond sensing molecules, ions or/and cations by fluorescence, colorimetry as well as by MALDI-TOF MS spectrometry can arise from these systems. A short brief on different examples activated by PET (photoinduced electron transfer), ICT (internal charge transfer) and EET (electronic energy transfer) phenomena will be provided. Finally the introduction of bio-inspired compounds derived from emissive amino acid or short peptide systems and nanoparticle devices to detect metal ions will be reviewed (202 references).