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1.
Cells ; 13(9)2024 Apr 24.
Artículo en Inglés | MEDLINE | ID: mdl-38727280

RESUMEN

Regenerative medicine harnesses stem cells' capacity to restore damaged tissues and organs. In vitro methods employing specific bioactive molecules, such as growth factors, bio-inductive scaffolds, 3D cultures, co-cultures, and mechanical stimuli, steer stem cells toward the desired differentiation pathways, mimicking their natural development. Chondrogenesis presents a challenge for regenerative medicine. This intricate process involves precise modulation of chondro-related transcription factors and pathways, critical for generating cartilage. Cartilage damage disrupts this process, impeding proper tissue healing due to its unique mechanical and anatomical characteristics. Consequently, the resultant tissue often forms fibrocartilage, which lacks adequate mechanical properties, posing a significant hurdle for effective regeneration. This review comprehensively explores studies showcasing the potential of amniotic mesenchymal stem cells (AMSCs) and amniotic epithelial cells (AECs) in chondrogenic differentiation. These cells exhibit innate characteristics that position them as promising candidates for regenerative medicine. Their capacity to differentiate toward chondrocytes offers a pathway for developing effective regenerative protocols. Understanding and leveraging the innate properties of AMSCs and AECs hold promise in addressing the challenges associated with cartilage repair, potentially offering superior outcomes in tissue regeneration.


Asunto(s)
Amnios , Diferenciación Celular , Condrogénesis , Humanos , Amnios/citología , Animales , Células Madre Mesenquimatosas/citología , Células Madre Mesenquimatosas/metabolismo , Células Epiteliales/citología , Células Epiteliales/metabolismo , Condrocitos/citología , Condrocitos/metabolismo , Medicina Regenerativa/métodos , Ingeniería de Tejidos/métodos
2.
Artif Intell Med ; 151: 102850, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38555849

RESUMEN

The ongoing digital revolution in the healthcare sector, emphasized by bodies like the US Food and Drug Administration (FDA), is paving the way for a shift towards person-centric healthcare models. These models consider individual needs, turning patients from passive recipients to active participants. A key factor in this shift is Artificial Intelligence (AI), which has the capacity to revolutionize healthcare delivery due to its ability to personalize it. With the rise of software in healthcare and the proliferation of the Internet of Things (IoT), a surge of digital data is being produced. This data, alongside improvements in AI's explainability, is facilitating the spread of person-centric healthcare models, aiming at improving health management and patient experience. This paper outlines a human-centered methodology for the development of an AI-as-a-service platform with the goal of broadening access to personalized healthcare. This approach places humans at its core, aiming to augment, not replace, human capabilities and integrate in current processes. The primary research question guiding this study is: "How can Human-Centered AI principles be considered when designing an AI-as-a-service platform that democratizes access to personalized healthcare?" This informed both our research direction and investigation. Our approach involves a design fiction methodology, engaging clinicians from different domains to gather their perspectives on how AI can meet their needs by envisioning potential future scenarios and addressing possible ethical and social challenges. Additionally, we incorporate Meta-Design principles, investigating opportunities for users to modify the AI system based on their experiences. This promotes a platform that evolves with the user and considers many different perspectives.


Asunto(s)
Inteligencia Artificial , Humanos , Medicina de Precisión/métodos , Atención a la Salud/organización & administración , Atención Dirigida al Paciente/organización & administración , Internet de las Cosas
3.
Int J Cardiol ; 404: 131981, 2024 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-38527629

RESUMEN

BACKGROUND: Machine learning (ML) employs algorithms that learn from data, building models with the potential to predict events by aggregating a large number of variables and assessing their complex interactions. The aim of this study is to assess ML potential in identifying patients with ischemic heart disease (IHD) at high risk of cardiac death (CD). METHODS: 3987 (mean age 68 ± 11) hospitalized IHD patients were enrolled. We implemented and compared various ML models and their combination into ensembles. Model output constitutes a new ML indicator to be employed for stratification. Primary variable importance was assessed with ablation tests. RESULTS: An ensemble classifier combining three ML models achieved the best performance to predict CD (AUROC of 0.830, F1-macro of 0.726). ML indicator use through Cox survival analysis outperformed the 18 variables individually, producing a better stratification compared to standard multivariate analysis (improvement of ∼20%). Patients in the low risk group defined through ML indicator had a significantly higher survival (88.8% versus 29.1%). The main variables identified were Dyslipidemia, LVEF, Previous CABG, Diabetes, Previous Myocardial Infarction, Smoke, Documented resting or exertional ischemia, with an AUROC of 0.791 and an F1-score of 0.674, lower than that of 18 variables. Both code and clinical data are freely available with this article. CONCLUSION: ML may allow a faster, low-cost and reliable evaluation of IHD patient prognosis by inclusion of more predictors and identification of those more significant, improving outcome prediction towards the development of precision medicine in this clinical field.


Asunto(s)
Infarto del Miocardio , Isquemia Miocárdica , Humanos , Persona de Mediana Edad , Anciano , Isquemia Miocárdica/diagnóstico , Aprendizaje Automático , Factores de Riesgo , Muerte
4.
Bioengineering (Basel) ; 11(2)2024 Feb 11.
Artículo en Inglés | MEDLINE | ID: mdl-38391662

RESUMEN

Considering the variability and heterogeneity of motor impairment in children with Movement Disorders (MDs), the assessment of postural control becomes essential. For its assessment, only a few tools objectively quantify and recognize the difference among children with MDs. In this study, we use the Virtual Reality Rehabilitation System (VRRS) for assessing the postural control in children with MD. Furthermore, 16 children (mean age 10.68 ± 3.62 years, range 4.29-18.22 years) were tested with VRRS by using a stabilometric balance platform. Postural parameters, related to the movements of the Centre of Pressure (COP), were collected and analyzed. Three different MD groups were identified according to the prevalent MD: dystonia, chorea and chorea-dystonia. Statistical analyses tested the differences among MD groups in the VRRS-derived COP variables. The mean distance, root mean square, excursion, velocity and frequency values of the dystonia group showed significant differences (p < 0.05) between the chorea group and the chorea-dystonia group. Technology provides quantitative data to support clinical assessment: in this case, the VRRS detected differences among the MD patterns, identifying specific group features. This tool could be useful also for monitoring the longitudinal trajectories and detecting post-treatment changes.

5.
Mater Today Bio ; 25: 101001, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38420144

RESUMEN

Tendon diseases pose a significant challenge in regenerative medicine due to the limited healing capacity of this tissue. Successful tendon regeneration requires a combination of angiogenesis, immune response, and tenogenesis processes. An effective tendon engineering (TE) strategy must finely tune this systems' interplay toward homeostasis. This study explores in vitro the paracrine influence of amniotic epithelial stem cells (AECs) engineered on a validated 3D electrospun PLGA scaffolds on HUVECs (angiogenesis), PBMCs/Jurkat (immune response), and AECs (tenogenic stem cell activation). The results revealed the role of scaffold's topology and topography in significantly modulating the paracrine profile of the cells. In detail, AECs basal release of bioactive molecules was boosted in the cells engineered on 3D scaffolds, in particular VEGF-D, b-FGF, RANTES, and PDGF-BB (p < 0.0001 vs. CMCTR). Moreover, biological tests demonstrated 3D scaffolds' proactive role in potentiating AECs' paracrine inhibition on PBMCs proliferation (CM3Dvs. CTR, p < 0.001) and LPS-mediated Jurkat activation with respect to controls (CM3D and CM2Dvs. CTR, p < 0.01 and p < 0.05, respectively), without exerting any in vitro pro-angiogenic role in promoting HUVECs proliferation and tubule formation. Teno-inductive paracrine ability of AECs engineered on 3D scaffolds was assessed on co-cultured ones, which formed tendon-like structures. These latter demonstrated an upregulation of tendon-related genes (SCX, THBS4, COL1, and TNMD) and the expression TNMD and COL1 proteins. Overall, this research underscores the pivotal role of the 3D topology and topography of PLGA tendon mimetic scaffolds in orchestrating effective tendon regeneration through modulating cell behavior and crosstalk between engineered stem cells and different subpopulations in the damaged tendon.

6.
Front Vet Sci ; 10: 1175346, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37180059

RESUMEN

There is high clinical demand for the resolution of tendinopathies, which affect mainly adult individuals and animals. Tendon damage resolution during the adult lifetime is not as effective as in earlier stages where complete restoration of tendon structure and property occurs. However, the molecular mechanisms underlying tendon regeneration remain unknown, limiting the development of targeted therapies. The research aim was to draw a comparative map of molecules that control tenogenesis and to exploit systems biology to model their signaling cascades and physiological paths. Using current literature data on molecular interactions in early tendon development, species-specific data collections were created. Then, computational analysis was used to construct Tendon NETworks in which information flow and molecular links were traced, prioritized, and enriched. Species-specific Tendon NETworks generated a data-driven computational framework based on three operative levels and a stage-dependent set of molecules and interactions (embryo-fetal or prepubertal) responsible, respectively, for signaling differentiation and morphogenesis, shaping tendon transcriptional program and downstream modeling of its fibrillogenesis toward a mature tissue. The computational network enrichment unveiled a more complex hierarchical organization of molecule interactions assigning a central role to neuro and endocrine axes which are novel and only partially explored systems for tenogenesis. Overall, this study emphasizes the value of system biology in linking the currently available disjointed molecular data, by establishing the direction and priority of signaling flows. Simultaneously, computational enrichment was critical in revealing new nodes and pathways to watch out for in promoting biomedical advances in tendon healing and developing targeted therapeutic strategies to improve current clinical interventions.

7.
Mol Reprod Dev ; 89(12): 646-654, 2022 12.
Artículo en Inglés | MEDLINE | ID: mdl-36444830

RESUMEN

Mitochondrial DNA (mtDNA) plays a crucial role in the development of a competent oocyte. Indeed, mtDNA alterations may predispose to chromosome nondisjunction, resulting in infertility due to a reduced vitality and quality of oocytes and embryos. In this methods paper, the multiple displacement amplification approach was applied in combination with next-generation sequencing (NGS) to amplify and sequence, in single-end, the entire mtDNA of single human oocytes to directly construct genomic NGS libraries, and subsequently, to highlight and quantify the mutations they presented. The bioinformatic workflow was carried out with a specific ad hoc developed in-house software. This approach proved to be sensitive and specific, also highlighting the mutations present in heteroplasmy, showing deletion, insertion or substitution mutations in the genes involved in the respiratory chain, even if the found variants were benign or of uncertain meaning. The analysis of mtDNA mutations in the oocyte could provide a better understanding of specific genetic abnormalities and of their possible effect on oocyte developmental competence. This study shows how this approach, based on a massive parallel sequencing of clonally amplified DNA molecules, allows to sequence the entire mitochondrial genome of single oocytes in a short time and with a single analytical run and to verify mtDNA mutations.


Asunto(s)
Heteroplasmia , Mitocondrias , Humanos , Mitocondrias/genética , ADN Mitocondrial/genética , Oocitos/metabolismo , Secuenciación de Nucleótidos de Alto Rendimiento/métodos
8.
Biomedicines ; 10(10)2022 Oct 14.
Artículo en Inglés | MEDLINE | ID: mdl-36289840

RESUMEN

Tendon tissue engineering aims to develop effective implantable scaffolds, with ideally the native tissue's characteristics, able to drive tissue regeneration. This research focused on fabricating tendon-like PLGA 3D biomimetic scaffolds with highly aligned fibers and verifying their influence on the biological potential of amniotic epithelial stem cells (AECs), in terms of tenodifferentiation and immunomodulation, with respect to fleeces. The produced 3D scaffolds better resemble native tendon tissue, both macroscopically, microscopically, and biomechanically. From a biological point of view, these constructs were able to instruct AECs genotypically and phenotypically. In fact, cells engineered on 3D scaffolds acquired an elongated tenocyte-like morphology; this was different from control AECs, which retained their polygonal morphology. The boosted AECs tenodifferentiation by 3D scaffolds was confirmed by the upregulation of tendon-related genes (SCX, COL1 and TNMD) and TNMD protein expression. The produced constructs also prompted AECs' immunomodulatory potential, both at the gene and paracrine level. This enhanced immunomodulatory profile was confirmed by a greater stimulatory effect on THP-1-activated macrophages. These biological effects have been related to the mechanotransducer YAP activation evidenced by its nuclear translocation. Overall, these results support the biomimicry of PLGA 3D scaffolds, revealing that not only fiber alignment but also scaffold topology provide an in vitro favorable tenodifferentiative and immunomodulatory microenvironment for AECs that could potentially stimulate tendon regeneration.

9.
Sensors (Basel) ; 22(13)2022 Jun 29.
Artículo en Inglés | MEDLINE | ID: mdl-35808430

RESUMEN

Wireless networks have drastically influenced our lifestyle, changing our workplaces and society. Among the variety of wireless technology, Wi-Fi surely plays a leading role, especially in local area networks. The spread of mobiles and tablets, and more recently, the advent of Internet of Things, have resulted in a multitude of Wi-Fi-enabled devices continuously sending data to the Internet and between each other. At the same time, Machine Learning has proven to be one of the most effective and versatile tools for the analysis of fast streaming data. This systematic review aims at studying the interaction between these technologies and how it has developed throughout their lifetimes. We used Scopus, Web of Science, and IEEE Xplore databases to retrieve paper abstracts and leveraged a topic modeling technique, namely, BERTopic, to analyze the resulting document corpus. After these steps, we inspected the obtained clusters and computed statistics to characterize and interpret the topics they refer to. Our results include both the applications of Wi-Fi sensing and the variety of Machine Learning algorithms used to tackle them. We also report how the Wi-Fi advances have affected sensing applications and the choice of the most suitable Machine Learning models.


Asunto(s)
Redes de Área Local , Aprendizaje Automático , Algoritmos , Bases de Datos Factuales , Tecnología Inalámbrica
10.
Cells ; 11(3)2022 01 27.
Artículo en Inglés | MEDLINE | ID: mdl-35159244

RESUMEN

Tendon disorders represent a very common pathology in today's population, and tendinopathies that account 30% of tendon-related injuries, affect yearly millions of people which in turn cause huge socioeconomic and health repercussions worldwide. Inflammation plays a prominent role in the development of tendon pathologies, and advances in understanding the underlying mechanisms during the inflammatory state have provided additional insights into its potential role in tendon disorders. Different cell compartments, in combination with secreted immune modulators, have shown to control and modulate the inflammatory response during tendinopathies. Stromal compartment represented by tenocytes has shown to display an important role in orchestrating the inflammatory response during tendon injuries due to the interplay they exhibit with the immune-sensing and infiltrating compartments, which belong to resident and recruited immune cells. The use of stem cells or their derived secretomes within the regenerative medicine field might represent synergic new therapeutical approaches that can be used to tune the reaction of immune cells within the damaged tissues. To this end, promising opportunities are headed to the stimulation of macrophages polarization towards anti-inflammatory phenotype together with the recruitment of stem cells, that possess immunomodulatory properties, able to infiltrate within the damaged tissues and improve tendinopathies resolution. Indeed, the comprehension of the interactions between tenocytes or stem cells with the immune cells might considerably modulate the immune reaction solving hence the inflammatory response and preventing fibrotic tissue formation. The purpose of this review is to compare the roles of distinct cell compartments during tendon homeostasis and injury. Furthermore, the role of immune cells in this field, as well as their interactions with stem cells and tenocytes during tendon regeneration, will be discussed to gain insights into new ways for dealing with tendinopathies.


Asunto(s)
Reconstitución Inmune , Tendinopatía , Traumatismos de los Tendones , Humanos , Traumatismos de los Tendones/terapia , Tendones , Tenocitos
11.
Cells ; 11(2)2022 01 13.
Artículo en Inglés | MEDLINE | ID: mdl-35053383

RESUMEN

Tendon injuries are at the frontier of innovative approaches to public health concerns and sectoral policy objectives. Indeed, these injuries remain difficult to manage due to tendon's poor healing ability ascribable to a hypo-cellularity and low vascularity, leading to the formation of a fibrotic tissue affecting its functionality. Tissue engineering represents a promising solution for the regeneration of damaged tendons with the aim to stimulate tissue regeneration or to produce functional implantable biomaterials. However, any technological advancement must take into consideration the role of the immune system in tissue regeneration and the potential of biomaterial scaffolds to control the immune signaling, creating a pro-regenerative environment. In this context, immunoengineering has emerged as a new discipline, developing innovative strategies for tendon injuries. It aims at designing scaffolds, in combination with engineered bioactive molecules and/or stem cells, able to modulate the interaction between the transplanted biomaterial-scaffold and the host tissue allowing a pro-regenerative immune response, therefore hindering fibrosis occurrence at the injury site and guiding tendon regeneration. Thus, this review is aimed at giving an overview on the role exerted from different tissue engineering actors in leading immunoregeneration by crosstalking with stem and immune cells to generate new paradigms in designing regenerative medicine approaches for tendon injuries.


Asunto(s)
Inmunidad , Regeneración/fisiología , Tendones/inmunología , Tendones/fisiología , Ingeniería de Tejidos , Andamios del Tejido/química , Animales , Humanos , Inmunomodulación
12.
Cells ; 10(11)2021 11 18.
Artículo en Inglés | MEDLINE | ID: mdl-34831443

RESUMEN

Electrospun poly(lactic-co-glycolic acid) (PLGA) scaffolds with highly aligned fibers (ha-PLGA) represent promising materials in the field of tendon tissue engineering (TE) due to their characteristics in mimicking fibrous extracellular matrix (ECM) of tendon native tissue. Among these properties, scaffold biodegradability must be controlled allowing its replacement by a neo-formed native tendon tissue in a controlled manner. In this study, ha-PLGA were subjected to hydrolytic degradation up to 20 weeks, under di-H2O and PBS conditions according to ISO 10993-13:2010. These were then characterized for their physical, morphological, and mechanical features. In vitro cytotoxicity tests were conducted on ovine amniotic epithelial stem cells (oAECs), up to 7 days, to assess the effect of non-buffered and buffered PLGA by-products at different concentrations on cell viability and their stimuli on oAECs' immunomodulatory properties. The ha-PLGA scaffolds degraded slowly as evidenced by a slight decrease in mass loss (14%) and average molecular weight (35%), with estimated degradation half-time of about 40 weeks under di-H2O. The ultrastructure morphology of the scaffolds showed no significant fiber degradation even after 20 weeks, but alteration of fiber alignment was already evident at week 1. Moreover, mechanical properties decreased throughout the degradation times under wet as well as dry PBS conditions. The influence of acid degradation media on oAECs was dose-dependent, with a considerable effect at 7 days' culture point. This effect was notably reduced by using buffered media. To a certain level, cells were able to compensate the generated inflammation-like microenvironment by upregulating IL-10 gene expression and favoring an anti-inflammatory rather than pro-inflammatory response. These in vitro results are essential to better understand the degradation behavior of ha-PLGA in vivo and the effect of their degradation by-products on affecting cell performance. Indeed, buffering the degradation milieu could represent a promising strategy to balance scaffold degradation. These findings give good hope with reference to the in vivo condition characterized by physiological buffering systems.


Asunto(s)
Ácidos/química , Amnios/citología , Células Epiteliales/citología , Inmunomodulación , Copolímero de Ácido Poliláctico-Ácido Poliglicólico/química , Células Madre/citología , Ingeniería de Tejidos , Andamios del Tejido/química , Animales , Forma de la Célula , Conductividad Eléctrica , Concentración de Iones de Hidrógeno , Interleucina-10/metabolismo , Interleucina-12/metabolismo , Peso Molecular , Ovinos
13.
PeerJ Comput Sci ; 7: e466, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33981837

RESUMEN

In this paper we investigate dynamic networks populated by autonomous mobile agents. Dynamic networks are networks whose topology can change continuously, at unpredictable locations and at unpredictable times. These changes are not considered to be faults, but rather an integral part of the nature of the system. The agents can autonomously move on the network, with the goal of solving cooperatively an assigned common task. Here, we focus on a specific network: the unoriented ring. More specifically, we study 1-interval connected dynamic rings (i.e., at any time, at most one of the edges might be missing). The agents move according to the widely used Look-Compute-Move life cycle, and can be homogenous (thus identical) or heterogenous (agents are assigned colors from a set of c > 1 colors). For identical agents, their goal is to form a compact segment, where agents occupy a continuous part of the ring and no two agents occupy the same node: we call this the Compact Configuration Problem. In the case of agents with colors, called the Colored Compact Configuration Problem, the goal is to group agents such that each group is formed by all agents having the same color, it occupies a continuous segment of the network, and groups of agents having different colors occupy distinct areas of the network. In this paper we determine the necessary conditions to solve both proposed problems. For all solvable cases, we provide algorithms for both the monochromatic and the colored version of the compact configuration problem. All our algorithms work even for the simplest model where agents have no persistent memory, no communication capabilities and do not agree on a common orientation within the network. To the best of our knowledge this is the first work on the compaction problem in a dynamic network.

14.
Org Lett ; 16(21): 5512-5, 2014 Nov 07.
Artículo en Inglés | MEDLINE | ID: mdl-25330411

RESUMEN

The synthesis of 1,2-cis-homoiminosugars bearing an NHAc group at the C-2 position is described. The key step to prepare these α-D-GlcNAc and α-D-GalNAc mimics utilizes a ß-amino alcohol skeletal rearrangement applied to an azepane precursor. This strategy also allows access to naturally occurring α-HGJ and α-HNJ. The α-D-GlcNAc-configured iminosugar was coupled to a glucoside acceptor to yield a novel pseudodisaccharide. Preliminary glycosidase inhibition evaluation indicates that the α-D-GalNAc-configured homoiminosugar is a potent and selective α-N-acetylgalactosaminidase inhibitor.


Asunto(s)
Amino Alcoholes/química , Amino Azúcares/química , Inhibidores Enzimáticos/química , Galactosamina/química , Glucosamina/química , alfa-N-Acetilgalactosaminidasa/antagonistas & inhibidores , alfa-N-Acetilgalactosaminidasa/química , Galactosamina/análogos & derivados , Glucosamina/análogos & derivados , Estructura Molecular
15.
Org Lett ; 16(21): 5516-9, 2014 Nov 07.
Artículo en Inglés | MEDLINE | ID: mdl-25330462

RESUMEN

The first synthesis of 1,2-trans-homoiminosugars devised as mimics of ß-D-GlcNAc and α-D-ManNAc is described. Key steps include a regioselective azidolysis of a cyclic sulfite and a ß-amino alcohol skeletal rearrangement applied to a polyhydroxylated azepane. The ß-D-GlcNAc derivative has been coupled to serine to deliver an iminosugar C-amino acid. The two homoiminosugars demonstrate moderate glycosidase inhibition.


Asunto(s)
Amino Alcoholes/síntesis química , Inhibidores Enzimáticos/química , Galactosamina/síntesis química , Glucosamina/síntesis química , Glicósido Hidrolasas/antagonistas & inhibidores , Glicósido Hidrolasas/química , Compuestos Heterocíclicos/química , Amino Alcoholes/química , Galactosamina/análogos & derivados , Galactosamina/química , Glucosamina/análogos & derivados , Glucosamina/química , Espectroscopía de Resonancia Magnética , Estructura Molecular
16.
Angew Chem Int Ed Engl ; 52(2): 639-44, 2013 Jan 07.
Artículo en Inglés | MEDLINE | ID: mdl-23172810

RESUMEN

Frustration leads to overreaction: when diametrically opposed regioselective debenzylation is frustrated, an unexpected double debenzylation reaction affords original tetrafunctionalized cyclodextrins in a controlled and efficient manner. A rationale of the reaction is proposed based on a kinetic study.


Asunto(s)
Compuestos Organometálicos/química , alfa-Ciclodextrinas/química , Modelos Moleculares , Estereoisomerismo
17.
Chem Commun (Camb) ; 46(34): 6255-7, 2010 Sep 14.
Artículo en Inglés | MEDLINE | ID: mdl-20668778

RESUMEN

New luminescent dinuclear rhenium(I) tricarbonyl complex-PNA conjugates have been synthesized through a reliable solid-phase synthetic methodology. Their photophysical properties have been measured. The most luminescent Re-PNA conjugate 7 showed interesting two-photon absorption (TPA) properties, that were exploited for imaging experiments, to demonstrate its easy uptake into living cells.


Asunto(s)
ADN/química , Luminiscencia , Ácidos Nucleicos de Péptidos/análisis , Ácidos Nucleicos de Péptidos/química , Renio/análisis , Renio/química , Línea Celular , ADN/análisis , ADN/metabolismo , Humanos , Estructura Molecular , Compuestos Organometálicos/análisis , Compuestos Organometálicos/síntesis química , Compuestos Organometálicos/química , Estereoisomerismo
18.
Chem Commun (Camb) ; (40): 6017-9, 2009 Oct 28.
Artículo en Inglés | MEDLINE | ID: mdl-19809629

RESUMEN

A versatile synthetic platform for the efficient immobilization of PNAs on magnetic iron oxides, providing magnetic nanosensors for selective DNA recognition, is presented.


Asunto(s)
ADN/química , Ácidos Nucleicos de Péptidos/química , Secuencia de Bases , Sitios de Unión , Magnetismo , Modelos Moleculares , Datos de Secuencia Molecular , Conformación de Ácido Nucleico
19.
J Am Chem Soc ; 131(13): 4783-7, 2009 Apr 08.
Artículo en Inglés | MEDLINE | ID: mdl-19173646

RESUMEN

Nanomaterials have been actively pursued for biological and medical applications in recent years. Here, we report the synthesis of several new poly(ethylene glycol) grafted branched polymers for functionalization of various nanomaterials including carbon nanotubes, gold nanoparticles (NPs), and gold nanorods (NRs), affording high aqueous solubility and stability for these materials. We synthesize different surfactant polymers based upon poly(gamma-glutamic acid) (gammaPGA) and poly(maleic anhydride-alt-1-octadecene) (PMHC18). We use the abundant free carboxylic acid groups of gammaPGA for attaching lipophilic species such as pyrene or phospholipid, which bind to nanomaterials via robust physisorption. Additionally, the remaining carboxylic acids on gammaPGA or the amine-reactive anhydrides of PMHC18 are then PEGylated, providing extended hydrophilic groups, affording polymeric amphiphiles. We show that single-walled carbon nanotubes (SWNTs), Au NPs, and NRs functionalized by the polymers exhibit high stability in aqueous solutions at different pH values, at elevated temperatures, and in serum. Moreover, the polymer-coated SWNTs exhibit remarkably long blood circulation (t(1/2) = 22.1 h) upon intravenous injection into mice, far exceeding the previous record of 5.4 h. The ultralong blood circulation time suggests greatly delayed clearance of nanomaterials by the reticuloendothelial system (RES) of mice, a highly desired property for in vivo applications of nanomaterials, including imaging and drug delivery.


Asunto(s)
Carbono/química , Oro/química , Nanoestructuras/química , Polietilenglicoles/química , Animales , Tiempo de Circulación Sanguínea , Ratones , Nanoestructuras/ultraestructura , Polietilenglicoles/síntesis química , Solubilidad
20.
J Am Chem Soc ; 131(1): 289-96, 2009 Jan 14.
Artículo en Inglés | MEDLINE | ID: mdl-19061329

RESUMEN

Nanomaterials hold much promise for biological applications, but they require appropriate functionalization to provide biocompatibility in biological environments. For noncovalent functionalization with biocompatible polymers, the polymer must also remain attached to the nanomaterial after removal of its excess to mimic the high-dilution conditions of administration in vivo. Reported here are the synthesis and utilization of singly substituted conjugates of dextran and a phospholipid (dextran-DSPE) as stable coatings for nanomaterials. Suspensions of single-walled carbon nanotubes were found not only to be stable to phosphate buffered saline (PBS), serum, and a variety of pH's after excess polymer removal, but also to provide brighter photoluminescence than carbon nanotubes suspended by poly(ethylene glycol)-DSPE. In addition, both gold nanoparticles (AuNPs) and gold nanorods (AuNRs) were found to maintain their dispersion and characteristic optical absorbance after transfer into dextran-DSPE and were obtained in much better yield than similar suspensions with PEG-phospholipid and commonly used thiol-PEG. These suspensions were also stable to PBS, serum, and a variety of pH's after removal of excess polymer. dextran-DSPE thus shows great promise as a general surfactant material for the functionalization of a variety of nanomaterials, which could facilitate future biological applications.


Asunto(s)
Materiales Biocompatibles Revestidos/síntesis química , Dextranos/química , Nanopartículas del Metal/química , Nanotubos de Carbono/química , Fosfatidiletanolaminas/química , Polietilenglicoles/química , Materiales Biocompatibles Revestidos/química , Estabilidad de Medicamentos , Mediciones Luminiscentes , Micelas , Nanotubos/química , Espectrometría de Fluorescencia
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