Raman spectroscopy to assess the differentiation of bone marrow mesenchymal stem cells into a glial phenotype.

Background: Mesenchymal stem cells (MSCs) are multipotent precursor cells with the ability to self-renew and differentiate into multiple cell linage, including the Schwann-like fate that promotes regeneration after lesion. Raman spectroscopy provides a precise characterization of the osteogenic, adipogenic, hepatogenic and myogenic differentiation of MSCs. However, the differentiation of bone marrow mesenchymal stem cells (BMSCs) towards a glial phenotype (Schwann-like cells) has not been characterized before using Raman spectroscopy. Method: We evaluated three conditions: 1) cell culture from rat bone marrow undifferentiated (uBMSCs), and two conditions of differentiation; 2) cells exposed to olfactory ensheathing cells-conditioned medium (dBMSCs) and 3) cells obtained from olfactory bulb (OECs). uBMSCs phenotyping was confirmed by morphology, immunocytochemistry and flow cytometry using antibodies of cell surface: CD90 and CD73. Glial phenotype of dBMSCs and OECs were verified by morphology and immunocytochemistry using markers of Schwann-like cells and OECs such as GFAP, p75 NTR and O4. Then, the Principal Component Analysis (PCA) of Raman spectroscopy was performed to discriminate components from the high wavenumber region between undifferentiated and glial-differentiated cells. Raman bands at the fingerprint region also were used to analyze the differentiation between conditions. Results: Differences between Raman spectra from uBMSC and glial phenotype groups were noted at multiple Raman shift values. A significant decrease in the concentration of all major cellular components, including nucleic acids, proteins, and lipids were found in the glial phenotype groups. PCA analysis confirmed that the highest spectral variations between groups came from the high wavenumber region observed in undifferentiated cells and contributed with the discrimination between glial phenotype groups. Conclusion: These findings support the use of Raman spectroscopy for the characterization of uBMSCs and its differentiation in the glial phenotype.

GLYPHOSATE IMPACT on human health and the environment: Sustainable alternatives to replace it in Mexico.

Glyphosate is a broad-spectrum, non-selective herbicide used to control weeds and protect agricultural crops, and it is classified as potentially carcinogenic by the International Agency for Research on Cancer. In Mexico, the use of pesticides is a common practice, including glyphosate. However, on December 31st, 2020, the Mexican government decreed the prohibition of this herbicide as of January 2024. In this review, we investigate the association between glyphosate and cancer risk and found that most of the studies focused using animals showing negative effects such as genotoxicity, cytotoxicity and neurotoxicity, some studies used cancer cell lines showing proliferative effects due to glyphosate exposure. To our knowledge, in Mexico, there are no scientific reports on the association of glyphosate with any type of cancer. In addition, we reviewed the toxicological effects of the herbicide glyphosate, and the specific case of the current situation of the use and environmental damage of this herbicide in Mexico. We found that few studies have been published on glyphosate, and that the largest number of publications are from the International Agency for Research on Cancer classification to date. Additionally, we provide data on glyphosate stimulation at low doses as a biostimulant in crops and analytical monitoring techniques for the detection of glyphosates in different matrices. Finally, we have tried to summarize the actions of the Mexican government to seek sustainable alternatives and replace the use of glyphosate, to obtain food free of this herbicide and take care of the health of the population and the environment.

Oxidative potential of metal-polluted urban dust as a potential environmental stressor for chronic diseases.

Oxidative stress (OS) associated with metals in urban dust has become a public health concern. Chronic diseases linked to general inflammation are particularly affected by OS. This research analyzes the spatial distribution of metals associated with OS, the urban dust´s oxidative potential (OP), and the occurrence of diseases whose treatments are affected by OS. We collected 70 urban dust samples during pre- and post-monsoon seasons to achieve this. We analyzed particle size distribution and morphology by scanning electron microscopy, as well as metal(loid)s by portable X-ray fluorescence, and OP of dust in artificial lysosomal fluid by using an ascorbic acid depletion assay. Our results show that the mean concentration of Fe, Pb, As, Cr, Cu, and V in pre-monsoon was 83,984.6, 98.4, 23.5, 165.8, 301.3, and 141.9 mg kg-1, while during post-monsoon was 50,638.8, 73.9, 16.7, 124.3, 178.9, and 133.5 mg kg-1, respectively. Impoverished areas with the highest presence of cardiovascular, cancer, diabetes, and respiratory diseases coincide with contaminated areas where young adults live. We identified significant differences in the OP between seasons. OP increases during the pre-monsoon (from 7.8 to 237.5 nmol AA min-1) compared to the post-monsoon season (from 1.6 to 163.2 nmol AA min-1). OP values are much higher than measured standards corresponding to contaminated soil and urban particulate matter, which means that additional sources beside metals cause the elevated OP. The results show no risk from chronic exposure to metals; however, our results highlight the importance of studying dust as an environmental factor that may potentially increase oxidative stress.

Release of Nanoparticles in the Environment and Catalytic Converters Ageing.

A Three-Way Catalyst (TWC) contains a cordierite ceramic monolith coated with a layer of Al2O3, CexZr1-xO2 and platinoids mixture. Under standard operation, the platinoid concentration decreases, exposing the remaining washcoat structure. After that particle release stage, the sintering process follows where the crystalline CexZr1-xO2 solution is broken and begins to separate into ZrO2 and CeO2 phases. ZrO2 is released to the environment as micro and nanoparticles, while a small amount of CeO2 generates a new AlxCe1-xO2 composite. The main effect of Ce capture is the growth in the size of the polycrystal structure from 86.13 ± 16.58 nm to 225.35 ± 69.51 nm. Moreover, a transformation of cordierite to mullite was identified by XRD analysis. Raman spectra showed that the oxygen vacancies (Vö) concentration decreased as CexZr1-xO2 phases separation occurred. The SEM-EDS revealed the incorporation of new spurious elements and microfractures favouring the detachment of the TWC support structure. The release of ultrafine particles is a consequence of catalytic devices overusing. The emission of refractory micro to nanocrystals to the atmosphere may represent an emerging public health issue underlining the importance of implementing strict worldwide regulations on regular TWCs replacement.

Conformational Behavior, Topographical Features, and Antioxidant Activity of Partly De-Esterified Arabinoxylans.

This study aimed to investigate the effect of arabinoxylans (AX) partial de-esterification with feruloyl esterase on the polysaccharide conformational behavior, topographical features, and antioxidant activity. After enzyme treatment, the ferulic acid (FA) content in AX was reduced from 7.30 to 5.48 µg FA/mg polysaccharide, and the molecule registered a small reduction in radius of gyration (RG), hydrodynamic radius (Rh), characteristic ratio (C∞), and persistence length (q). A slight decrease in α and a small increase in K constants in the Mark-Houwink-Sakurada equation for partially de-esterified AX (FAX) suggested a reduction in molecule structural rigidity and a more expanded coil conformation, respectively, in relation to AX. Fourier transform infrared spectroscopy spectra of AX and FAX presented a pattern characteristic for this polysaccharide. Atomic force microscopy topographic analysis of FAX showed a more regular surface without larger hollows in relation to AX. The antioxidant activity of FAX, compared to AX, was reduced by 30 and 41% using both 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS+) and 1,1-diphenyl-2-picryl-hydrazyl (DPPH) methods, respectively. These results suggest that feruloyl esterase treatment of AX could offer a strategy to tailor AX chains conformation, morphological features, and antioxidant activity, impacting the development of advanced biomaterials for biomedical and pharmaceutical applications.

Raman spectroscopy and silver nanoparticles for efficient detection of membrane proteins in living cells.

Molecular fingerprints revealed by Raman techniques show great potential for biomedical applications, like disease diagnostic through Raman detection of tumor markers and other molecules in the cell membrane. However, SERS substrates used in membrane molecule studies produce enhanced Raman spectra of high variability and challenging band assignments that limit their application. In this work, these drawbacks are addressed to detect membrane-associated hemoglobin (Hbm) in human erythrocytes through Raman spectroscopy. These cells are incubated with silver nanoparticles (AgNPs) in PBS before Raman measurements. Our results showed that AgNPs form large aggregates in PBS that adhered to the erythrocyte membrane, which enhances Raman scattering by molecules around the membrane, like Hbm. Also, deoxyHb markers may allow Hbmdetection in Raman spectra of oxygenated erythrocytes (oxyRBCs). Raman spectra of oxyRBCs incubated with AgNPs showed enhanced deoxyHb signals with good spectral reproducibility, supporting the Hbmdetection through deoxyHb markers. Instead, Raman spectra of oxyRBCs showed oxyHb bands associated with free cytoplasmic hemoglobin. Other factors influencing Raman detection of membrane proteins are discussed, like bothz-position and dimension of the sample volume. The results encourage membrane protein studies in living cells using Raman spectroscopy, leading to the characterization and diagnostic of different pathologies through a non-invasive technique.

Nanoscale Changes on RBC Membrane Induced by Storage and Ionizing Radiation: A Mini-Review.

The storage lesions and the irradiation of blood cellular components for medical procedures in blood banks are events that may induce nanochanges in the membrane of red blood cells (RBCs). Alterations, such as the formation of pores and vesicles, reduce flexibility and compromise the overall erythrocyte integrity. This review discusses the alterations on erythrocytic lipid membrane bilayer through their characterization by confocal scanning microscopy, Raman, scanning electron microscopy, and atomic force microscopy techniques. The interrelated experimental results may address and shed light on the correlation of biomechanical and biochemical transformations induced in the membrane and cytoskeleton of stored and gamma-irradiated RBC. To highlight the main advantages of combining these experimental techniques simultaneously or sequentially, we discuss how those outcomes observed at micro- and nanoscale cell levels are useful as biomarkers of cell aging and storage damage.

Effects of Untreated Drinking Water at Three Indigenous Yaqui Towns in Mexico: Insights from a Murine Model.

BACKGROUND: Reports in a northwestern Mexico state linked arsenic (As) in drinking water to DNA damage in people from indigenous communities. However, this correlation remains under discussion due to unknown variables related to nutrition, customs, and the potential presence of other metal(oid)s. METHODS: To determine this association, we sampled water from three Yaqui towns (Cócorit, Vícam, and Pótam), and analyzed the metals by ICP-OES. We exposed four separate groups, with five male CD-1 mice each, to provide further insight into the potential effects of untreated drinking water. RESULTS: The maximum concentrations of each metal(oid) in µg·L-1 were Sr(819) > Zn(135) > As(75) > Ba(57) > Mo(56) > Cu(17) > Al(14) > Mn(12) > Se(19). Histological studies revealed brain cells with angulation, satellitosis, and reactive gliosis with significant statistical correlation with Mn and As. Furthermore, the liver cells presented hepatocellular degeneration. Despite the early response, there is no occurrence of both statistical and significative changes in hematological parameters. CONCLUSIONS: The obtained results provide experimental insights to understand the potential effects of untreated water with low As and Mn contents in murine models. This fact is noteworthy because of the development of histological changes on both the brain and liver at subchronic exposure.

Identification of refractory zirconia from catalytic converters in dust: An emerging pollutant in urban environments.

Using catalytic converters is one of the most effective methods to control vehicle emissions. A washcoat of cerium oxide-zirconia (CeO2-ZrO2) has been used to enhance the performance of the catalytic converter device. To date, the prevalence of this material in the environment has not been assessed. In this study, we present evidence of the existence of inhalable zirconia in urban dust. Samples of the washcoat, exhaust pipe, topsoil, and road dust were analyzed by X-ray fluorescence, X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy, photoluminescence (PL) spectroscopy, and thermally stimulated luminescence (TSL). The results showed a CeO2-ZrO2 phase separation after sintering. This causes the emission of ZrO2, CeO2, and CeZrOx particles smaller than 1 µm, which can likely reach the alveolar macrophages in the lungs. The Ce-Zr content in road dust exceeds geogenic levels, and a significant correlation of 0.87 (p < 0.05) reflects a common anthropic source. Chronic exposure to such refractory particles may result in the development of non-occupational respiratory diseases. The inhalable crystalline compounds emitted by vehicles are a significant environmental health hazard, revealing the need for further investigation and assessment of zirconia levels generated by automobiles in urban areas worldwide.

Albumin-Albumin/Lactosylated Core-Shell Nanoparticles: Therapy to Treat Hepatocellular Carcinoma for Controlled Delivery of Doxorubicin.

Doxorubicin (Dox) is the most widely used chemotherapeutic agent and is considered a highly powerful and broad-spectrum for cancer treatment. However, its application is compromised by the cumulative side effect of dose-dependent cardiotoxicity. Because of this, targeted drug delivery systems (DDS) are currently being explored in an attempt to reduce Dox systemic side-effects. In this study, DDS targeting hepatocellular carcinoma (HCC) has been designed, specifically to the asialoglycoprotein receptor (ASGPR). Dox-loaded albumin-albumin/lactosylated (core-shell) nanoparticles (tBSA/BSALac NPs) with low (LC) and high (HC) crosslink using glutaraldehyde were synthesized. Nanoparticles presented spherical shapes with a size distribution of 257 ± 14 nm and 254 ± 14 nm, as well as an estimated surface charge of -28.0 ± 0.1 mV and -26.0 ± 0.2 mV, respectively. The encapsulation efficiency of Dox for the two types of nanoparticles was higher than 80%. The in vitro drug release results showed a sustained and controlled release profile. Additionally, the nanoparticles were revealed to be biocompatible with red blood cells (RBCs) and human liver cancer cells (HepG2 cells). In cytotoxicity assays, Dox-loaded nanoparticles decrease cell viability more efficiently than free Dox. Specific biorecognition assays confirmed the interaction between nanoparticles and HepG2 cells, especially with ASGPRs. Both types of nanoparticles may be possible DDS specifically targeting HCC, thus reducing side effects, mainly cardiotoxicity. Therefore, improving the quality of life from patients during chemotherapy.

Identification of inhalable rutile and polycyclic aromatic hydrocarbons (PAHs) nanoparticles in the atmospheric dust.

Addressing the presence of rutile nanoparticles (NPs) in the air is a work in progress, and the development of methodologies for the identification of NPs in atmospheric dust is essential for the assessment of its toxicological effects. To address this issue, we selected the fast growing desertic city of Hermosillo in northern Mexico. Road dust (n = 266) and soils (n = 10) were sampled and bulk Ti-contents were tested by portable X-ray fluorescence. NPs were extracted from atmospheric dust by PM1.0-PTFE filters and further characterized by Confocal Raman Microscopy, Energy-dispersive X-ray spectroscopy (EDS) coupled to Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM). Results showed (i) the average concentration of Ti in road dust (3447 mg kg-1) was similar to natural values and worldwide urban dusts; (ii) the bulk geochemistry was not satisfactory for Ti-NPs identification; (iii) 76% of the total extracted PM1.0 sample corresponded to NPs; (iv) mono-microaggregates of rutile NPs were identified; (v) ubiquitous polycyclic aromatic hydrocarbons (PAHs) were linked to NPs. The genotoxicity of rutile and PAHs, in connection with NPs content, make us aware of a crucial emerging environmental issue of significant health concern, justifying further research in this field.

Metal bioaccessibility, particle size distribution and polydispersity of playground dust in synthetic lysosomal fluids.

Inhalation of playground dust-derived fine particles in schoolyards poses a risk from exposure to metal(oids) and minerals. In this work, we obtained the total concentration and bioaccessibility of metal(oids) with Gamble Solution (GS) and Artificial Lysosomal Fluid (ALF) synthetic solutions, simulating the extracellular neutral pH environment of the lung and the intracellular conditions of the macrophage, respectively. Scanning Electron Microscope (SEM), and Dynamic Light Scattering analysis (DLS) techniques were used to characterize particles with a size smaller than 2.5 µm, which can be assimilated by macrophages in the deep part of the lung. Arsenic (As), lead (Pb), copper (Cu), manganese (Mn), zinc (Zn), and iron (Fe) showed concentrations of 39.9, 147.9, 286, 1369, 2313, 112,457 mg·kg-1, respectively. The results indicated that all studied elements were enriched when compared to (i) local geochemical background and (ii) findings reported in other cities around the world. Bioaccessibility of metal(oids) in GS was low-moderate for most studied elements. However, in ALF assays, bioaccessibility was high among the samples: for lead (Pb = 34-100%), arsenic (As = 14.7-100%), copper (Cu = 17.9-100%), and zinc (Zn = 35-52%) possibly related to hydrophobic minerals in dust. SEM and DLS image analysis showed that playground dust particles smaller than 2.5 µm are dominant, particularly particles with a size range of 500-600 nm. The polydispersity detected in these particle sizes showed that most of them might be crystalline compounds (elongated shapes) forming agglomerates instead of combustion particles (spheres). Moreover, the circularity detected varies from 0.57 to 0.79 (low roundness), which corroborates this finding. The presence of agglomerates of ultrafine/nanoparticles containing highly bioaccessible metals in playground sites may have severe implications in children's health. Therefore, further studies are required to characterize the size distribution, structure, shape and composition of such minerals which are essential factors related to the toxicology of inhaled dust particles.

Atomic force microscopy and Raman spectra profile of blood components associated with exposure to cigarette smoking.

Tobacco smoke contains several compounds with oxidant and pro-oxidant properties with the capability of producing structural changes in biomolecules, as well as cell damage. This work aimed to describe and analyse the effect of tobacco smoke on human blood components, red blood cell (RBC) membrane, haemoglobin (Hb) and blood plasma by Atomic Force Microscopy (AFM) and Raman spectroscopy. Our results indicate that tobacco induced RBC membrane nano-alterations characterized by diminished RBC diameter and increased nano-vesicles formation, and RBC fragility. The Raman spectra profile suggests modifications in chemical composition specifically found in peaks 1135 cm-1, 1156 cm-1, 1452 cm-1 and intensity relation of peaks 1195 cm-1 and 1210 cm-1 of blood plasma and by change of peaks 1338 cm-1, 1357 cm-1, 1549 cm-1 and 1605 cm-1 associated with the pyrrole ring of Hb. The relevance of these results lies in the identification of a profile of structural and chemical alterations that serves as a biomarker of physiological and pathological conditions in the human blood components induced by tobacco exposure using AFM and the Raman spectroscopy as tools for monitoring them.

A magnetic immunoconjugate nanoplatform for easy colorimetric detection of the NS1 protein of dengue virus in infected serum.

In this work, as a proof of principle, the design and performance evaluation of a simple, cheap and efficient colorimetric test for the detection of the NS1 protein of dengue virus, assisted by an immunoconjugate of magnetite (Fe3O4) nanoparticles coupled to anti-NS1 antibodies is reported. A monoclonal antibody against the NS1 antigen was covalently immobilized on the surface of superparamagnetic iron oxide nanoparticles (SPIONs ∼ 20 nm) and used for the immunodetection of this protein. When the magnetic immuno-nanoplatform is added into infected serum, it conjugates with the NS1 protein and can then be easily separated using an external magnetic field; then, the recovered immunoconjugate is transferred into a well containing a second immobilized NS1-antibody to form an ELISA-type system. When the NS1 protein is present, a color change to blue is induced by reaction with the Perls reagent, which is consistent with the formation of a SPION-antibody-NS1 antigen-antibody conjugate that confirms infection. No false positives were found when NS1 was not present or a different antibody and the NS1 protein were added into the system. The experimental findings could be extrapolated and scaled up to lead to future developments of simple, quick, and inexpensive, in situ biomolecular diagnostic tests for emergent viral infections.

Lactosylated Albumin Nanoparticles: Potential Drug Nanovehicles with Selective Targeting Toward an In Vitro Model of Hepatocellular Carcinoma.

Hepatocellular carcinoma (HCC) ranks fifth in occurrence and second in mortality of all cancers. The development of effective therapies for HCC is urgently needed. Anticancer drugs targeted to the liver-specific asialoglycoprotein receptors (ASGPRs) are viewed as a promising potential treatment for HCC. ASGPRs facilitate the recognition and endocytosis of molecules, and possibly vehicles with galactose end groups, by the liver. In this study, bovine serum albumin (BSA) was conjugated with lactose using a thermal treatment. The formation of lactosylated BSA (BSA-Lac) was confirmed by a change of the chemical structure, increased molecular mass, and Ricinus communis lectin recognition. Subsequently, the low-crosslinking BSA-Lac nanoparticles (LC BSA-Lac NPs) and high-crosslinking BSA-Lac nanoparticles (HC BSA-Lac NPs) were synthesized. These nanoparticles presented spherical shapes with a size distribution of 560 ± 18.0 nm and 539 ± 9.0 nm, as well as an estimated surface charge of -26 ± 0.15 mV and -24 ± 0.45 mV, respectively. Both BSA-Lac NPs were selectively recognized by ASGPRs as shown by biorecognition, competition, and inhibition assays using an in vitro model of HCC. This justifies pursuing the strategy of using BSA-Lac NPs as potential drug nanovehicles with selective direction toward hepatocellular carcinoma.

Specific capture of glycosylated graphene oxide by an asialoglycoprotein receptor: a strategic approach for liver-targeting.

In this work, we report the evaluation of lactosylated graphene oxide (GO-AL) as a potential drug carrier targeted at an asialoglycoprotein receptor (ASGPR) from hepatic cancer cells. Structural-modification, safety evaluation, and functional analysis of GO-AL were performed. The structure and morphology of the composite were analyzed by scanning electron microscopy (SEM) and atomic force microscopy (AFM), while Raman and FTIR spectroscopy were used to track the chemical modification. For the safe application of GO-AL, an evaluation of the cytotoxic effect, hemolytic properties, and specific interactions of the glycoconjugate were also studied. SEM and AFM analysis of the GO showed graphene sheets with a layer size of 2-3 nm, though a few of them reached 4 nm. The Raman spectra presented characteristic peaks of graphene oxide at 1608 cm-1 and 1350 cm-1, corresponding to G and D bands, respectively. Besides, Si-O peaks for the APTES conjugates of GO were identified by FTIR spectroscopy. No cytotoxic or hemolytic effects were observed for GO samples, thus proving their biocompatibility. The interaction of Ricinus communis lectin confirmed that GO-AL has a biorecognition capability and an exposed galactose structure. This biorecognition capability was accompanied by the determination of the specific absorption of lactosylated GO by HepG2 cells mediated through the asialoglycoprotein receptor. The successful conjugation, hemolytic safety, and specific recognition described here for lactosylated GO indicate its promise as an efficient drug-delivery vehicle to hepatic tissue.

Effect of gamma irradiation doses in the structural and functional properties of mice splenic cells.

PURPOSE: Ionizing radiation is nowadays effectively used in cancer treatments. However, the effect of irradiation in immune-system cells is poorly understood and remains controversial. The aim of this work was to determine the effect of γ-irradiation in the structural and functional properties of mice splenic cells. MATERIALS AND METHODS: Structural traits of irradiated splenic cells were evaluated by Atomic Force Microscopy and Raman spectroscopy. Functional properties were measured by gene and protein expression by RT-qPCR and ELISA, respectively. The induced cytotoxic effect was evaluated by MTT assay and the phagocytic capability by flow cytometry. RESULTS: Membrane roughness and molecular composition of splenic adherent cells are not changed by irradiation doses exposure. An increase in transcription of pro-inflammatory cytokines was observed. While protein expression decreased in IL-2 dose-dependent, relevant differences were identified in the anti-inflammatory marker IL-10 at 27 Gy. An increase of cytotoxicity in irradiated cells at 7 Gy and 27 Gy doses was observed, while phagocytosis was slight increased at 7 Gy dose but not statistically significant. CONCLUSIONS: We have demonstrated that γ-irradiation affects the splenic cells and changes the cytokines profile toward a pro-inflammatory phenotype and a tendency to increase the cytotoxicity was found, which implies a stimulation of immune response induced by γ-irradiation.

Nanodiamonds and gold nanoparticles to obtain a hybrid nanostructure with potential applications in biomedicine.

Using detonation nanodiamonds and fluorescent nitrogen-vacancy center nanodiamonds, linked to gold nanoparticles, we synthesized two hybrid nanostructures (HGDs) that were subsequently conjugated with a fluorophore. An amplification effect induced by the gold nanoparticles increased the emission spectrum of the fluorophore, maximizing the possibilities for imaging applications of these HGDs. The incubation of the nanostructures with HeLa cells produced no alteration of cell viability after 3 h and showed the presence of nanostructures in the cell cytoplasm at 24 h. These observations also indicate the potential biomedical use of the proposed HGDs.

Source apportionment and environmental fate of lead chromates in atmospheric dust in arid environments.

The environmental fate of lead derived from traffic paint has been poorly studied in developing countries, mainly in arid zones. For this purpose, a developing city located in the Sonoran desert (Hermosillo, Mexico), was chosen to conduct a study. In this paper the lead chromate (crocoite) sources in atmospheric dust were addressed using a combination of Raman microspectroscopy, X-ray diffraction, scanning electron microscopy (SEM), and Pb isotope measurements. A high concentration of Pb and Cr as micro- and nanostructured pigments of crocoite is reported in yellow traffic paint (n=80), road dust (n=146), settled dust in roofs (n=21), and atmospheric dust (n=20) from a developing city located in the Sonoran Desert. 10 samples of peri-urban soils were collected for local geochemical background. The paint photodegradation and erosion of the asphaltic cover are enhanced by the climate, and the presence of the mineral crocoite (PbCrO4) in road dust with an aerodynamic diameter ranging from 100nm to 2µm suggests its integration into the atmosphere by wind resuspension processes. A positive PbCr correlation (R2=0.977) was found for all studied samples, suggesting a common source. The Pb-isotope data show signatures in atmospheric dust as a product of the mixing of two end members: i) local soils and ii) crocoite crystals as pigments in paint. The presence of lead chromates in atmospheric dust has not been previously documented in Latin America, and it represents an unknown health risk to the exposed population because the identified size of crystals can reach the deepest part of lungs.

Molecular recognition of glyconanoparticles by RCA and E. coli K88 - designing transports for targeted therapy.

The targeted drug delivery has been studied as one of the main methods in medicine to ensure successful treatments of diseases. Pharmaceutical sciences are using micro or nano carriers to obtain a controlled delivery of drugs, able to selectively interact with pathogens, cells or tissues. In this work, we modified bovine serum albumin (BSA) with lactose, obtaining a neoglycan (BSA-Lac). Subsequently, we synthesized glyconanoparticles (NPBSA-Lac) with the premise that it would be recognized by microbial galactose specific lectins. NPBSA-Lac were tested for bio-recognition with adhesins of E. coli K88 and Ricinus communis agglutinin I (RCA). Glycation of BSA with lactose was analyzed by electrophoresis, infrared spectroscopy and fluorescence. Approximately 41 lactoses per BSA molecule were estimated. Nanoparticles were obtained using water in oil emulsion method and spheroid morphology with a range size of 300-500 nm was observed. Specific recognition of NPBSA-Lac by RCA and E. coli K88 was displayed by aggregation of nanoparticles analyzed by dynamic light scattering and atomic force microscopy. The results indicate that the lactosylated nanovectors could be targeted at the E. coli K88 adhesin and potentially could be used as a transporter for an antibacterial drug.