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1.
Proc Natl Acad Sci U S A ; 120(32): e2304318120, 2023 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-37523534

RESUMO

The large-scale implementation of renewable energy systems necessitates the development of energy storage solutions to effectively manage imbalances between energy supply and demand. Herein, we investigate such a scalable material solution for energy storage in supercapacitors constructed from readily available material precursors that can be locally sourced from virtually anywhere on the planet, namely cement, water, and carbon black. We characterize our carbon-cement electrodes by combining correlative EDS-Raman spectroscopy with capacitance measurements derived from cyclic voltammetry and galvanostatic charge-discharge experiments using integer and fractional derivatives to correct for rate and current intensity effects. Texture analysis reveals that the hydration reactions of cement in the presence of carbon generate a fractal-like electron-conducting carbon network that permeates the load-bearing cement-based matrix. The energy storage capacity of this space-filling carbon black network of the high specific surface area accessible to charge storage is shown to be an intensive quantity, whereas the high-rate capability of the carbon-cement electrodes exhibits self-similarity due to the hydration porosity available for charge transport. This intensive and self-similar nature of energy storage and rate capability represents an opportunity for mass scaling from electrode to structural scales. The availability, versatility, and scalability of these carbon-cement supercapacitors opens a horizon for the design of multifunctional structures that leverage high energy storage capacity, high-rate charge/discharge capabilities, and structural strength for sustainable residential and industrial applications ranging from energy autarkic shelters and self-charging roads for electric vehicles, to intermittent energy storage for wind turbines and tidal power stations.

2.
Langmuir ; 37(23): 7019-7031, 2021 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-34096309

RESUMO

Concrete is one of the most used materials in the world, second only to water. One of the key advantages of this versatile material is its workability in the early stages before setting. Here, we use in situ underwater Raman microspectroscopy to investigate and visualize the early hydration kinetics of ordinary Portland cement (OPC) with submicron spatial and high temporal resolution. First, the spectral features of the C-S-H gel were analyzed in the hydroxyl stretching region to confirm the coexistence of Ca-OH and Si-OH bonds in a highly disordered C-S-H gel. Second, the disordered calcium hydroxide (Ca(OH)2) is experimentally identified for the first time in the mixture before setting, suggesting that Ca(OH)2 crystallization and growth are essential in the setting of cement paste. Finally, the phase transformations of clinker, C-S-H, and Ca(OH)2 are spatially and temporally resolved, and the hydration kinetics are studied by analyzing the spatial relationships of these phases using two-point correlation functions. The results quantitatively validate that the setting occurs as a percolation process, wherein the hydration products intersect and form an interconnected network. This time-space-resolved characterization method can map and quantitatively analyze the heterogeneous reaction of the cementitious colloidal system and thus provide potential application value in the field of cement chemistry and materials design more broadly.

3.
Proc Natl Acad Sci U S A ; 114(40): 10542-10547, 2017 10 03.
Artigo em Inglês | MEDLINE | ID: mdl-28923958

RESUMO

Skeletal metastases, the leading cause of death in advanced breast cancer patients, depend on tumor cell interactions with the mineralized bone extracellular matrix. Bone mineral is largely composed of hydroxyapatite (HA) nanocrystals with physicochemical properties that vary significantly by anatomical location, age, and pathology. However, it remains unclear whether bone regions typically targeted by metastatic breast cancer feature distinct HA materials properties. Here we combined high-resolution X-ray scattering analysis with large-area Raman imaging, backscattered electron microscopy, histopathology, and microcomputed tomography to characterize HA in mouse models of advanced breast cancer in relevant skeletal locations. The proximal tibial metaphysis served as a common metastatic site in our studies; we identified that in disease-free bones this skeletal region contained smaller and less-oriented HA nanocrystals relative to ones that constitute the diaphysis. We further observed that osteolytic bone metastasis led to a decrease in HA nanocrystal size and perfection in remnant metaphyseal trabecular bone. Interestingly, in a model of localized breast cancer, metaphyseal HA nanocrystals were also smaller and less perfect than in corresponding bone in disease-free controls. Collectively, these results suggest that skeletal sites prone to tumor cell dissemination contain less-mature HA (i.e., smaller, less-perfect, and less-oriented crystals) and that primary tumors can further increase HA immaturity even before secondary tumor formation, mimicking alterations present during tibial metastasis. Engineered tumor models recapitulating these spatiotemporal dynamics will permit assessing the functional relevance of the detected changes to the progression and treatment of breast cancer bone metastasis.


Assuntos
Densidade Óssea , Neoplasias Ósseas , Neoplasias da Mama , Nanopartículas , Tíbia , Microtomografia por Raio-X , Animais , Neoplasias Ósseas/diagnóstico por imagem , Neoplasias Ósseas/metabolismo , Neoplasias Ósseas/secundário , Neoplasias da Mama/diagnóstico por imagem , Neoplasias da Mama/metabolismo , Linhagem Celular Tumoral , Durapatita/metabolismo , Feminino , Xenoenxertos , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Metástase Neoplásica , Transplante de Neoplasias , Tíbia/diagnóstico por imagem , Tíbia/metabolismo
4.
Psychiatr Danub ; 32(Suppl 4): 505-510, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33212456

RESUMO

BACKGROUND: Multiple sclerosis (MS) as chronic neurodegenerative disease significantly impact patients' quality of life (QoL). QoL instruments can be generic (EQ-5D, SF-36) and disease-specific like MSQoL-54. Use of disease-specific instruments is preferred since it captures broader symptoms related to MS than generic instruments. Mental health is impacted by MS and different psychiatric conditions significantly impact QoL. We have conducted prospective non-interventional study among MS patients. Aim was to measure and compare MS patients QoL by generic and disease-specific instrument at baseline and after one year and to identify potential correlation between these two types of measurements and to assess mental health scores among MS patients in Bosnia and Herzegovina (B&H) and other countries. SUBJECTS AND METHODS: Study included 62 patients diagnosed with MS and treated at Neurology clinic in Sarajevo from April 2016 to May 2017. Study was approved by Ethical Committee. QoL has been measured by EQ-5D and MSQoL-54. Measurement has been performed at baseline and after 12 months. RESULTS: Average utility score measured by EQ-5D at the baseline and end of the study were 0.688 and 0.639 respectively with no significant difference (p=0.850). EQ-5D utility and MSQoL-54 score showed high correlation at baseline; rho=0.873 p=0.0001 for physical health and rho=0.711 p=0.0001 for mental health. At the end of the study no significant correlations have been found (p>0.05). High negative correlation found between EDSS and scores measured by EQ-5D and MSQoL-54; at baseline (rho=-0.744 p=0.0001) and at the end of the study (rho=-0.832 p=0.0001). Similar MS impact and loss of QoL found in B&H and other countries. CONCLUSIONS: Both instruments can be used in measuring QoL but disease-specific are preferred since they capture broader symptoms impacting MS patient QoL. Using QoL instruments could drive clinician decision and patient-centric care as well as reimbursement and policy decision by recording treatment outcomes.


Assuntos
Inquéritos Epidemiológicos , Transtornos Mentais/diagnóstico , Transtornos Mentais/psicologia , Saúde Mental , Esclerose Múltipla/psicologia , Qualidade de Vida , Adulto , Bósnia e Herzegóvina , Feminino , Humanos , Masculino , Transtornos Mentais/complicações , Pessoa de Meia-Idade , Esclerose Múltipla/complicações , Estudos Prospectivos
5.
J Struct Biol ; 202(1): 25-34, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29221896

RESUMO

Microcalcifications (MCs) are routinely used to detect breast cancer in mammography. Little is known, however, about their materials properties and associated organic matrix, or their correlation to breast cancer prognosis. We combine histopathology, Raman microscopy, and electron microscopy to image MCs within snap-frozen human breast tissue and generate micron-scale resolution correlative maps of crystalline phase, trace metals, particle morphology, and organic matrix chemical signatures within high grade ductal carcinoma in situ (DCIS) and invasive cancer. We reveal the heterogeneity of mineral-matrix pairings, including punctate apatitic particles (<2 µm) with associated trace elements (e.g., F, Na, and unexpectedly Al) distributed within the necrotic cores of DCIS, and both apatite and spheroidal whitlockite particles in invasive cancer within a matrix containing spectroscopic signatures of collagen, non-collagen proteins, cholesterol, carotenoids, and DNA. Among the three DCIS samples, we identify key similarities in MC morphology and distribution, supporting a dystrophic mineralization pathway. This multimodal methodology lays the groundwork for establishing MC heterogeneity in the context of breast cancer biology, and could dramatically improve current prognostic models.


Assuntos
Neoplasias da Mama/metabolismo , Mama/metabolismo , Calcinose/metabolismo , Carcinoma Intraductal não Infiltrante/metabolismo , Idoso , Mama/patologia , Mama/ultraestrutura , Neoplasias da Mama/diagnóstico por imagem , Calcinose/diagnóstico por imagem , Carcinoma Intraductal não Infiltrante/diagnóstico por imagem , Fenômenos Químicos , Feminino , Humanos , Mamografia , Microscopia Eletrônica , Pessoa de Meia-Idade , Sensibilidade e Especificidade , Espectrometria por Raios X , Microtomografia por Raio-X
6.
Angew Chem Int Ed Engl ; 57(25): 7288-7295, 2018 06 18.
Artigo em Inglês | MEDLINE | ID: mdl-29154403

RESUMO

The process of mimicking properties of specific interest (such as mechanical, optical, and structural) observed in ancient and historical systems is designated here as paleo-inspiration. For instance, recovery in archaeology or paleontology identifies materials that are a posteriori extremely resilient to alteration. All the more encouraging is that many ancient materials were synthesized in soft chemical ways, often using low-energy resources and sometimes rudimentary manufacturing equipment. In this Minireview, ancient systems are presented as a source of inspiration for innovative material design in the Anthropocene.

7.
Med Arch ; 71(2): 103-106, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28790539

RESUMO

INTRODUCTION: The purpose of this study was to validate Bosnian translation of disease specific quality of life measure MSQoL-54 which is widely used in practice. MATERIAL AND METHODS: Previously translated and culturally adopted MSQoL-54 questionnaire used in this study has been provided and licensed by Optum Inc. The questionnaire was validated in 62 MS patients seen at Neurology clinic at University Clinical Center Sarajevo, during April 2016 until May 2016. Internal reliabilities of Bosnian version MSQoL-54 were assessed for multiple item scales by using Cronbach's alpha coefficient. Clinical validity was assessed comparing means of the two summary MSQoL-54 scores by the EDSS score. Pearson's (r) correlation coefficient was used to investigate the relationship between the composite scores and the main clinical and demographic variables. RESULTS: Patients' participation was satisfactory and all scales fulfilled the usual psychometric standards. Highly significant inverse relationship was found between both composite scores and clinical characteristics of the disease and the EDSS. The lowest internal consistency reliability is found on social function scale (0.743), overall quality of life (0.782) and pain (0.833). The highest internal consistency reliability is found on role limitations due to physical problems (0.959), physical health (0.962) and role limitations due to emotional problems (0.966). The mean value of MSQoL-54 PHC (Physical Health Composite) and MHC (Mental Health Composite) were 49.82±18.90 (36.05-61.38) 51.84±22.22 (34.93-70.20) respectively. Our study has shown that the Bosnian version of MSQoL-54 is easy to administer and well accepted by patients and may be useful as clinical outcome measures in patients with MS.


Assuntos
Esclerose Múltipla Recidivante-Remitente/psicologia , Qualidade de Vida , Inquéritos e Questionários/normas , Adulto , Bósnia e Herzegóvina , Feminino , Humanos , Masculino , Traduções
8.
Anal Chem ; 88(7): 3826-35, 2016 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-26959687

RESUMO

Here, we show results on X-ray absorption near edge structure spectroscopy in both transmission and X-ray fluorescence full-field mode (FF-XANES) at the calcium K-edge on human bone tissue in healthy and diseased conditions and for different tissue maturation stages. We observe that the dominating spectral differences originating from different tissue regions, which are well pronounced in the white line and postedge structures are associated with polarization effects. These polarization effects dominate the spectral variance and must be well understood and modeled before analyzing the very subtle spectral variations related to the bone tissue variations itself. However, these modulations in the fine structure of the spectra can potentially be of high interest to quantify orientations of the apatite crystals in highly structured tissue matrices such as bone. Due to the extremely short wavelengths of X-rays, FF-XANES overcomes the limited spatial resolution of other optical and spectroscopic techniques exploiting visible light. Since the field of view in FF-XANES is rather large the acquisition times for analyzing the same region are short compared to, for example, X-ray diffraction techniques. Our results on the angular absorption dependence were verified by both site-matched polarized Raman spectroscopy, which has been shown to be sensitive to the orientation of bone building blocks and by mathematical simulations of the angular absorbance dependence. As an outlook we further demonstrate the polarization based assessment of calcium-containing crystal orientation and specification of calcium in a beta-tricalcium phosphate (ß-Ca3(PO4)2 scaffold implanted into ovine bone. Regarding the use of XANES to assess chemical properties of Ca in human bone tissue our data suggest that neither the anatomical site (tibia vs jaw) nor pathology (healthy vs necrotic jaw bone tissue) affected the averaged spectral shape of the XANES spectra.


Assuntos
Cálcio/química , Osso Cortical/química , Minerais/química , Espectroscopia por Absorção de Raios X , Fosfatos de Cálcio/química , Simulação por Computador , Fluorescência , Humanos , Análise Espectral Raman , Raios X
9.
J Struct Biol ; 189(3): 269-75, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25557499

RESUMO

The heterogeneous and site-specific incorporation of inorganic ions can profoundly influence the local mechanical properties of damage tolerant biological composites. Using the sea urchin tooth as a research model, we describe a multi-technique approach to spatially map the distribution of magnesium in this complex multiphase system. Through the combined use of 16-bit backscattered scanning electron microscopy, multi-channel energy dispersive spectroscopy elemental mapping, and diffraction-limited confocal Raman spectroscopy, we demonstrate a new set of high throughput, multi-spectral, high resolution methods for the large scale characterization of mineralized biological materials. In addition, instrument hardware and data collection protocols can be modified such that several of these measurements can be performed on irregularly shaped samples with complex surface geometries and without the need for extensive sample preparation. Using these approaches, in conjunction with whole animal micro-computed tomography studies, we have been able to spatially resolve micron and sub-micron structural features across macroscopic length scales on entire urchin tooth cross-sections and correlate these complex morphological features with local variability in elemental composition.


Assuntos
Dente/química , Animais , Processamento de Imagem Assistida por Computador , Magnésio/análise , Microscopia Eletrônica de Varredura , Ouriços-do-Mar , Espectrometria por Raios X , Análise Espectral Raman/métodos , Microtomografia por Raio-X
10.
J Struct Biol ; 192(3): 358-365, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26431896

RESUMO

Sea urchin embryos sequester calcium from the sea water. This calcium is deposited in a concentrated form in granule bearing vesicles both in the epithelium and in mesenchymal cells. Here we use in vivo calcein labeling and confocal Raman spectroscopy, as well as cryo-FIB-SEM 3D structural reconstructions, to investigate the processes occurring in the internal cavity of the embryo, the blastocoel. We demonstrate that calcein stained granules are also present in the filopodial network within the blastocoel. Simultaneous fluorescence imaging and Raman spectroscopy show that these granules do contain a calcium mineral. By tracking the movements of these granules, we show that the granules in the epithelium and primary mesenchymal cells barely move, but those in the filopodial network move long distances. We could however not detect any unidirectional movement of the filopodial granules. We also show the presence of mineral containing multivesicular vesicles that also move in the filopodial network. We conclude that the filopodial network is an integral part of the mineral transport process, and possibly also for sequestering calcium and other ions. Although much of the sequestered calcium is deposited in the mineralized skeleton, a significant amount is used for other purposes, and this may be temporarily stored in these membrane-delineated intracellular deposits.


Assuntos
Calcificação Fisiológica , Cálcio/metabolismo , Grânulos Citoplasmáticos/metabolismo , Embrião não Mamífero/metabolismo , Paracentrotus/embriologia , Pseudópodes/metabolismo , Animais , Transporte Biológico , Carbonato de Cálcio/metabolismo , Microscopia Crioeletrônica , Microscopia Eletrônica de Varredura , Análise Espectral Raman
11.
J Struct Biol ; 189(1): 28-36, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25433275

RESUMO

Previous studies on pre-molt gastroliths have shown a typical onion-like morphology of layers of amorphous mineral (mostly calcium carbonate) and chitin, resulting from the continuous deposition and densification of amorphous mineral spheres on a chitin-matrix during time. To investigate the consequences of this layered growth on the local structure and composition of the gastrolith, we performed spatially-resolved Raman, X-ray and SEM-EDS analysis on complete pre-molt gastrolith cross-sections. Results show that especially the abundance of inorganic phosphate, phosphoenolpyruvate (PEP)/citrate and proteins is not uniform throughout the organ but changes from layer to layer. Based on these results we can conclude that ACC stabilization in the gastrolith takes place by more than one compound and not by only one of these additives.


Assuntos
Astacoidea/química , Calcificação Fisiológica/fisiologia , Carbonato de Cálcio/química , Quitina/química , Estômago/química , Animais , Microscopia Eletrônica de Varredura , Espectrometria por Raios X , Análise Espectral Raman
12.
Small ; 11(11): 1320-7, 2015 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-25367373

RESUMO

The real-time temperature measurement of nanostructured materials is particularly attractive in view of increasing needs of local temperature probing with high sensitivity and resolution in nanoelectronics, integrated photonics, and biomedicine. Light-induced heating and Raman scattering of single-walled carbon nanotubes with adsorbed gold nanoparticles decorating silica microparticles are reported, by both green and near IR lasers. The plasmonic shell is used as nanoheater, while the single-walled carbon nanotubes are Raman active and serve as a thermometer. Stokes and Anti-Stokes Raman spectra of single-walled carbon nanotubes serve to estimate the effective light-induced temperature rise on the metal nanoparticles. The temperature rise is constant with time, indicating stability of the adsorption density. The effective temperatures derived from Stokes and Anti-Stokes intensities are correlated with those measured in a heating stage. The resolution of the thermal experiments in our study was found to be 5-40 K.


Assuntos
Ouro/química , Teste de Materiais/métodos , Nanopartículas Metálicas/química , Nanotubos de Carbono/química , Análise Espectral Raman/métodos , Termografia/métodos , Ouro/efeitos da radiação , Luz , Nanopartículas Metálicas/efeitos da radiação , Nanotubos de Carbono/efeitos da radiação
13.
Analyst ; 140(15): 4981-6, 2015 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-26040199

RESUMO

Herein, we have designed composite SERS-active micro-satellites, which exhibit a dual role: (i) effective probes for determining cellular composition and (ii) optically movable and easily detectable markers. The satellites were synthesized by the layer-by-layer assisted decoration of silica microparticles with metal (gold or silver) nanoparticles and astralen in order to ensure satellite SERS-based microenvironment probing and satellite recognition, respectively. A combination of optical tweezers and Raman spectroscopy can be used to navigate the satellites to a certain cellular compartment and probe the intracellular composition following cellular uptake. In the future, this developed approach may serve as a tool for single cell analysis with nanometer precision due to the multilayer surface design, focusing on both extracellular and intracellular studies.


Assuntos
Fibroblastos/citologia , Pinças Ópticas , Dióxido de Silício/química , Análise de Célula Única/instrumentação , Análise Espectral Raman/instrumentação , Animais , Linhagem Celular , Desenho de Equipamento , Ouro/química , Nanopartículas Metálicas/química , Camundongos , Prata/química
14.
Molecules ; 20(4): 5835-50, 2015 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-25849806

RESUMO

Bone material is composed of an organic matrix of collagen fibers and apatite nanoparticles. Previously, vibrational spectroscopy techniques such as infrared (IR) and Raman spectroscopy have proved to be particularly useful for characterizing the two constituent organic and inorganic phases of bone. In this work, we tested the potential use of high intensity synchrotron-based far-IR radiation (50-500 cm(-1)) to gain new insights into structure and chemical composition of bovine fibrolamellar bone. The results from our study can be summarized in the following four points: (I) compared to far-IR spectra obtained from synthetic hydroxyapatite powder, those from fibrolamellar bone showed similar peak positions, but very different peak widths; (II) during stepwise demineralization of the bone samples, there was no significant change neither to far-IR peak width nor position, demonstrating that mineral dissolution occurred in a uniform manner; (III) application of external loading on fully demineralized bone had no significant effect on the obtained spectra, while dehydration of samples resulted in clear differences. (IV) using linear dichroism, we showed that the anisotropic structure of fibrolamellar bone is also reflected in anisotropic far-IR absorbance properties of both the organic and inorganic phases. Far-IR spectroscopy thus provides a novel way to functionally characterize bone structure and chemistry, and with further technological improvements, has the potential to become a useful clinical diagnostic tool to better assess quality of collagen-based tissues.


Assuntos
Técnica de Desmineralização Óssea/métodos , Fêmur/química , Espectrofotometria Infravermelho/instrumentação , Espectrofotometria Infravermelho/métodos , Animais , Anisotropia , Apatitas/química , Densidade Óssea , Calcificação Fisiológica , Bovinos , Colágeno/química , Modelos Biológicos
15.
J Struct Biol ; 187(3): 266-275, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25025981

RESUMO

Chemical composition and fibrillar organization are the major determinants of osteonal bone mechanics. However, prominent methodologies commonly applied to investigate mechanical properties of bone on the micro scale are usually not able to concurrently describe both factors. In this study, we used polarized Raman spectroscopy (PRS) to simultaneously analyze structural and chemical information of collagen fibrils in human osteonal bone in a single experiment. Specifically, the three-dimensional arrangement of collagen fibrils in osteonal lamellae was assessed. By analyzing the anisotropic intensity of the amide I Raman band of collagen as a function of the orientation of the incident laser polarization, different parameters related to the orientation of the collagen fibrils and the degree of alignment of the fibrils were derived. Based on the analysis of several osteons, two major fibrillar organization patterns were identified, one with a monotonic and another with a periodically changing twist direction. These results confirm earlier reported twisted and oscillating plywood arrangements, respectively. Furthermore, indicators of the degree of alignment suggested the presence of disordered collagen within the lamellar organization of the osteon. The results show the versatility of the analytical PRS approach and demonstrate its capability in providing not only compositional, but also 3D structural information in a complex hierarchically structured biological material. The concurrent assessment of chemical and structural features may contribute to a comprehensive characterization of the microstructure of bone and other collagen-based tissues.


Assuntos
Colágenos Fibrilares/análise , Ósteon/metabolismo , Imageamento Tridimensional/métodos , Análise Espectral Raman/métodos , Simulação por Computador , Fêmur/metabolismo , Colágenos Fibrilares/química , Colágenos Fibrilares/metabolismo , Humanos , Modelos Moleculares
16.
Biomacromolecules ; 15(5): 1579-85, 2014 May 12.
Artigo em Inglês | MEDLINE | ID: mdl-24650082

RESUMO

Hydrogel systems based on cross-linked polymeric materials which could provide both adhesion and cohesion in wet environment have been considered as a promising formulation of tissue adhesives. Inspired by marine mussel adhesion, many researchers have tried to exploit the 3,4-dihydroxyphenylalanine (DOPA) molecule as a cross-linking mediator of synthetic polymer-based hydrogels which is known to be able to achieve cohesive hardening as well as adhesive bonding with diverse surfaces. Beside DOPA residue, composition of other amino acid residues and structure of mussel adhesive proteins (MAPs) have also been considered important elements for mussel adhesion. Herein, we represent a novel protein-based hydrogel system using DOPA-containing recombinant MAP. Gelation can be achieved using both oxdiation-induced DOPA quinone-mediated covalent and Fe(3+)-mediated coordinative noncovalent cross-linking. Fe(3+)-mediated hydrogels show deformable and self-healing viscoelastic behavior in rheological analysis, which is also well-reflected in bulk adhesion strength measurement. Quinone-mediated hydrogel has higher cohesive strength and can provide sufficient gelation time for easier handling. Collectively, our newly developed MAP hydrogel can potentially be used as tissue adhesive and sealant for future applications.


Assuntos
Bivalves/química , Di-Hidroxifenilalanina/química , Hidrogéis/química , Proteínas/química , Animais , Estrutura Molecular , Reologia
17.
Small ; 9(3): 351-6, 2013 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-23047321

RESUMO

Gold nanoparticle aggregate carbon nanotube functionalized colloidal particles serve as an efficient platform for probing the intracellular environment. The probes provide the means of effective localization of signal and detection of molecular fingerprints of biomolecules in living cells. The approach demonstrated in this work opens significant opportunities in molecular imaging as well as intracellular sensing and trafficking.


Assuntos
Ouro/química , Nanopartículas Metálicas/química , Análise Espectral Raman/métodos , Nanotubos de Carbono/química
18.
Langmuir ; 29(34): 10899-906, 2013 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-23865752

RESUMO

Biological materials offer a wide range of multifunctional and structural properties that are currently not achieved in synthetic materials. Herein we report on the synthesis and preparation of bioinspired organic/inorganic composites that mimic the key physicochemical features associated with the mechanical strengthening of both squid beaks and mussel thread coatings using chitosan as an initial template. While chitosan is a well-known biocompatible material, it suffers from key drawbacks that have limited its usage in a wider range of structural biomedical applications. First, its load-bearing capability in hydrated conditions remains poor, and second it completely dissolves at pH < 6, preventing its use in mild acidic microenvironments. In order to overcome these intrinsic limitations, a chitosan-based organic/inorganic biocomposite is prepared that mimics the interfacial chemistry of squid beaks and mussel thread coating. Chitosan was functionalized with catechol moieties in a highly controlled fashion and combined with superparamagnetic iron oxide (γ-Fe2O3) nanoparticles to give composites that represent a significant improvement in functionality of chitosan-based biomaterials. The inorganic/organic (γ-Fe2O3/catechol) interfaces are stabilized and strengthened by coordination bonding, resulting in hybrid composites with improved stability at high temperatures, physiological pH conditions, and acid/base conditions. The inclusion of superparamagnetic particles also makes the composites stimuli-responsive.


Assuntos
Bivalves , Catecóis/química , Quitosana/química , Decapodiformes , Compostos Férricos/química , Nanopartículas/química , Animais , Biomimética/métodos
19.
Biomacromolecules ; 14(4): 1072-7, 2013 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-23452271

RESUMO

The underwater adhesion of marine mussels relies on mussel foot proteins (mfps) rich in the catecholic amino acid 3,4-dihydroxyphenylalanine (Dopa). As a side chain, Dopa is capable of strong bidentate interactions with a variety of surfaces, including many minerals and metal oxides. Titanium is among the most widely used medical implant material and quickly forms a TiO2 passivation layer under physiological conditions. Understanding the binding mechanism of Dopa to TiO2 surfaces is therefore of considerable theoretical and practical interest. Using a surface forces apparatus, we explored the force-distance profiles and adhesion energies of mussel foot protein 3 (mfp-3) to TiO2 surfaces at three different pHs (pH 3, 5.5 and 7.5). At pH 3, mfp-3 showed the strongest adhesion force on TiO2, with an adhesion energy of ∼-7.0 mJ/m(2). Increasing the pH gives rise to two opposing effects: (1) increased oxidation of Dopa, thus, decreasing availability for the Dopa-mediated adhesion, and (2) increased bidentate Dopa-Ti coordination, leading to the further stabilization of the Dopa group and, thus, an increase in adhesion force. Both effects were reflected in the resonance-enhanced Raman spectra obtained at the three deposition pHs. The two competing effects give rise to a higher adhesion force of mfp-3 on the TiO2 surface at pH 7.5 than at pH 5.5. Our results suggest that Dopa-containing proteins and synthetic polymers have great potential as coating materials for medical implant materials, particularly if redox activity can be controlled.


Assuntos
Di-Hidroxifenilalanina/química , Proteínas/química , Titânio/química , Adesividade , Animais , Bivalves , Concentração de Íons de Hidrogênio , Oxirredução , Próteses e Implantes , Análise Espectral Raman
20.
PNAS Nexus ; 2(3): pgad052, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37007709

RESUMO

Addressing the existing gap between currently available mitigation strategies for greenhouse gas emissions associated with ordinary Portland cement production and the 2050 carbon neutrality goal represents a significant challenge. In order to bridge this gap, one potential option is the direct gaseous sequestration and storage of anthropogenic CO2 in concrete through forced carbonate mineralization in both the cementing minerals and their aggregates. To better clarify the potential strategic benefits of these processes, here, we apply an integrated correlative time- and space-resolved Raman microscopy and indentation approach to investigate the underlying mechanisms and chemomechanics of cement carbonation over time scales ranging from the first few hours to several days using bicarbonate-substituted alite as a model system. In these reactions, the carbonation of transient disordered calcium hydroxide particles at the hydration site leads to the formation of a series of calcium carbonate polymorphs including disordered calcium carbonate, ikaite, vaterite, and calcite, which serve as nucleation sites for the formation of a calcium carbonate/calcium-silicate-hydrate (C-S-H) composite, and the subsequent acceleration of the curing process. The results from these studies reveal that in contrast to late-stage cement carbonation processes, these early stage (precure) out-of-equilibrium carbonation reactions do not compromise the material's structural integrity, while allowing significant quantities of CO2 (up to 15 w%) to be incorporated into the cementing matrix. The out-of-equilibrium carbonation of hydrating clinker thus provides an avenue for reducing the environmental footprint of cementitious materials via the uptake and long-term storage of anthropogenic CO2.

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