Benchtop X-ray fluorescence imaging as a tool to study gold nanoparticle penetration in 3D cancer spheroids.

The use of nanomaterials to improve medical diagnostics and therapeutics has been rapidly increasing. Among these materials are gold nanoparticles, which can be functionalized to target specific cells, acting as nanovectors for drug delivery, enhanced contrast agents as well as other targeted therapies. Au nanoparticles are very useful as they selectively accumulate in tumour sites due to the enhanced permeability-retention effect. There is however little information about the spatial distribution of the nanoparticles within tumours, which might hinder efficient therapies. In this study, X-ray fluorescence was used to investigate the diffusion of gold nanoparticles in cancer cell spheroids mimicking true tumour growth. Functionalization of the nanoparticles has the effect of allowing better diffusion into and out of the spheroid, while those nanoparticles that are only partially covered rapidly formed aggregates. This clustering led to size exclusion during transport within the tumour, changing its distribution profile while greatly increasing the nanoparticle concentration.

Iterative Analog-Digital Multi-User Equalizer for Wideband Millimeter Wave Massive MIMO Systems.

Most of the previous work on hybrid transmit and receive beamforming focused on narrowband channels. Because the millimeter wave channels are expected to be wideband, it is crucial to propose efficient solutions for frequency-selective channels. In this regard, this paper proposes an iterative analog-digital multi-user equalizer scheme for the uplink of wideband millimeter-wave massive multiple-input-multiple-output (MIMO) systems. By iterative equalizer we mean that both analog and digital parts are updated using as input the estimates obtained at the previous iteration. The proposed iterative analog-digital multi-user equalizer is designed by minimizing the sum of the mean square error of the data estimates over the subcarriers. We assume that the analog part is fixed for all subcarriers while the digital part is computed on a per subcarrier basis. Due to the complexity of the resulting optimization problem, a sequential approach is proposed to compute the analog phase shifters values for each radio frequency (RF) chain. We also derive an accurate, semi-analytical approach for obtaining the bit error rate (BER) of the proposed hybrid system. The proposed solution is compared with other hybrid equalizer schemes, recently designed for wideband millimeter-wave (mmWave) massive MIMO systems. The simulation results show that the performance of the developed analog-digital multi-user equalizer is close to full-digital counterpart and outperforms the previous hybrid approach.

Targeting Cancer Resistance via Multifunctional Gold Nanoparticles.

Resistance to chemotherapy is a major problem facing current cancer therapy, which is continuously aiming at the development of new compounds that are capable of tackling tumors that developed resistance toward common chemotherapeutic agents, such as doxorubicin (DOX). Alongside the development of new generations of compounds, nanotechnology-based delivery strategies can significantly improve the in vivo drug stability and target specificity for overcoming drug resistance. In this study, multifunctional gold nanoparticles (AuNP) have been used as a nanoplatform for the targeted delivery of an original anticancer agent, a Zn(II) coordination compound [Zn(DION)2]Cl2 (ZnD), toward better efficacy against DOX-resistant colorectal carcinoma cells (HCT116 DR). Selective delivery of the ZnD nanosystem to cancer cells was achieved by active targeting via cetuximab, NanoZnD, which significantly inhibited cell proliferation and triggered the death of resistant tumor cells, thus improving efficacy. In vivo studies in a colorectal DOX-resistant model corroborated the capability of NanoZnD for the selective targeting of cancer cells, leading to a reduction of tumor growth without systemic toxicity. This approach highlights the potential of gold nanoformulations for the targeting of drug-resistant cancer cells.

Nanotheranostics Targeting the Tumor Microenvironment.

Cancer is considered the most aggressive malignancy to humans, and definitely the major cause of death worldwide. Despite the different and heterogenous presentation of the disease, there are pivotal cell elements involved in proliferation, differentiation, and immortalization, and ultimately the capability to evade treatment strategies. This is of utmost relevance when we are just beginning to grasp the complexity of the tumor environment and the molecular "evolution" within. The tumor micro-environment (TME) is thought to provide for differentiation niches for clonal development that results in tremendous cancer heterogeneity. To date, conventional cancer therapeutic strategies against cancer are failing to tackle the intricate interplay of actors within the TME. Nanomedicine has been proposing innovative strategies to tackle this TME and the cancer cells that simultaneously provide for biodistribution and/or assessment of action. These nanotheranostics systems are usually multi-functional nanosystems capable to carry and deliver active cargo to the site of interest and provide diagnostics capability, enabling early detection, and destruction of cancer cells in a more selective way. Some of the most promising multifunctional nanosystems are based on gold nanoparticles, whose physic-chemical properties have prompt for the development of multifunctional, responsive nanomedicines suitable for combinatory therapy and theranostics. Herein, we shall focus on the recent developments relying on the properties of gold nanoparticles as the basis for nanotheranostics systems against the heterogeneity within the TME.

Combination of chemotherapy and Au-nanoparticle photothermy in the visible light to tackle doxorubicin resistance in cancer cells.

Despite great advances in the fight against cancer, traditional chemotherapy has been hindered by the dose dependent adverse side effects that reduce the usable doses for effective therapy. This has been associated to drug resistance in tumor cells that often cause relapse and therapy failure. These drawbacks have been tackled by combining different therapeutic regiments that prevent drug resistance while decreasing the chemotherapy dose required for efficacious ablation of cancer. In fact, new metallic compounds have been in a continuous development to extend the existing chemotherapy arsenal for these combined regimens. Here, we demonstrate that combination of a metallic compound (TS265), previously characterized by our group, with photothermy circumvents cells resistant to Doxorubicin (DOX). We first engendered a colorectal carcinoma cell line (HCT116) highly resistant to DOX, whose viability was diminished after administration of TS265. Cancer cell death was potentiated by challenging these cells with 14 nm spherical gold nanoparticles followed by laser irradiation at 532 nm. The combination of TS265 with photothermy lead to 65% cell death of the DOX resistant cells without impacting healthy cells. These results support the use of combined chemotherapy and photothermy in the visible spectrum as an efficient tool for drug resistant tumors.

Potentiating angiogenesis arrest in vivo via laser irradiation of peptide functionalised gold nanoparticles.

BACKGROUND: Anti-angiogenic therapy has great potential for cancer therapy with several FDA approved formulations but there are considerable side effects upon the normal blood vessels that decrease the potential application of such therapeutics. Chicken chorioallantoic membrane (CAM) has been used as a model to study angiogenesis in vivo. Using a CAM model, it had been previously shown that spherical gold nanoparticles functionalised with an anti-angiogenic peptide can humper neo-angiogenesis. RESULTS: Our results show that gold nanoparticles conjugated with an anti-angiogenic peptide can be combined with visible laser irradiation to enhance angiogenesis arrest in vivo. We show that a green laser coupled to gold nanoparticles can achieve high localized temperatures able to precisely cauterize blood vessels. This combined therapy acts via VEGFR pathway inhibition, leading to a fourfold reduction in FLT-1 expression. CONCLUSIONS: The proposed phototherapy extends the use of visible lasers in clinics, combining it with chemotherapy to potentiate cancer treatment. This approach allows the reduction of dose of anti-angiogenic peptide, thus reducing possible side effects, while destroying blood vessels supply critical for tumour progression.

Photothermal enhancement of chemotherapy in breast cancer by visible irradiation of Gold Nanoparticles.

Photothermal Therapy (PTT) impact in cancer therapy has been increasing due to the enhanced photothermal capabilities of a new generation of nanoscale photothermal agents. Among these nanoscale agents, gold nanoshells and nanorods have demonstrated optimal properties for translation of near infra-red radiation into heat at the site of interest. However, smaller spherical gold nanoparticles (AuNPs) are easier to produce, less toxic and show improved photoconversion capability that may profit from the irradiation in the visible via standard surgical green lasers. Here we show the efficient light-to-heat conversion of spherical 14 nm AuNPs irradiated in the visible region (at the surface plasmons resonance peak) and its application to selectively obliterate cancer cells. Using breast cancer as model, we show a synergistic interaction between heat (photoconversion at 530 nm) and cytotoxic action by doxorubicin with clear advantages to those of the individual therapy approaches.

Current trends in molecular diagnostics of chronic myeloid leukemia.

Nearly 1.5 million people worldwide suffer from chronic myeloid leukemia (CML), characterized by the genetic translocation t(9;22)(q34;q11.2), involving the fusion of the Abelson oncogene (ABL1) with the breakpoint cluster region (BCR) gene. Early onset diagnosis coupled to current therapeutics allow for a treatment success rate of 90, which has focused research on the development of novel diagnostics approaches. In this review, we present a critical perspective on current strategies for CML diagnostics, comparing to gold standard methodologies and with an eye on the future trends on nanotheranostics.

Gold Nanoparticles for Diagnostics: Advances towards Points of Care.

The remarkable physicochemical properties of gold nanoparticles (AuNPs) have prompted developments in the exploration of biomolecular interactions with AuNP-containing systems, in particular for biomedical applications in diagnostics. These systems show great promise in improving sensitivity, ease of operation and portability. Despite this endeavor, most platforms have yet to reach maturity and make their way into clinics or points of care (POC). Here, we present an overview of emerging and available molecular diagnostics using AuNPs for biomedical sensing that are currently being translated to the clinical setting.

One nanoprobe, two pathogens: gold nanoprobes multiplexing for point-of-care.

BACKGROUND: Gold nanoparticles have been widely employed for biosensing purposes with remarkable efficacy for DNA detection. Amongst the proposed systems, colorimetric strategies based on the remarkable optical properties have provided for simple yet effective sequence discrimination with potential for molecular diagnostics at point of need. These systems may also been used for parallel detection of several targets to provide additional information on diagnostics of pathogens. RESULTS: For the first time, we demonstrate that a single Au-nanoprobe may provide for detection of two distinct targets (pathogens) allowing colorimetric multi-target detection. We demonstrate this concept by using one single gold-nanoprobe capable to detect members of the Mycobacterium tuberculosis complex and Plasmodium sp., the etiologic agents of tuberculosis and malaria, respectively. Following characterisation, the developed gold-nanoprobe allowed detection of either target in individual samples or in samples containing both DNA species with the same efficacy. CONCLUSIONS: Using one single probe via the non-cross-linking colorimetric methodology it is possible to identify multiple targets in one sample in one reaction. This proof-of-concept approach may easily be integrated into sensing platforms allowing for fast and simple multiplexing of Au-nanoprobe based detection at point-of-need.

Gold nanoprobe-based non-crosslinking hybridization for molecular diagnostics.

Non-crosslinking (NCL) approaches using DNA-modified gold nanoparticles for molecular detection constitute powerful tools with potential implications in clinical diagnostics and tailored medicine. From detection of pathogenic agents to identification of specific point mutations associated with health conditions, these methods have shown remarkable versatility and simplicity. Herein, the NCL hybridization assay is broken down to the fundamentals behind its assembly and detection principle. Gold nanoparticle synthesis and derivatization is addressed, emphasizing optimal size homogeneity and conditions for maximum surface coverage, with direct implications in downstream detection. The detection principle is discussed and the advantages and drawbacks of different NCL approaches are discussed. Finally, NCL-based applications for molecular detection of clinically relevant loci and potential integration into more complex biosensing platforms, projecting miniaturization and portability are addressed.

Gold Nanotheranostics: Proof-of-Concept or Clinical Tool?

Nanoparticles have been making their way in biomedical applications and personalized medicine, allowing for the coupling of diagnostics and therapeutics into a single nanomaterial-nanotheranostics. Gold nanoparticles, in particular, have unique features that make them excellent nanomaterials for theranostics, enabling the integration of targeting, imaging and therapeutics in a single platform, with proven applicability in the management of heterogeneous diseases, such as cancer. In this review, we focus on gold nanoparticle-based theranostics at the lab bench, through pre-clinical and clinical stages. With few products facing clinical trials, much remains to be done to effectively assess the real benefits of nanotheranostics at the clinical level. Hence, we also discuss the efforts currently being made to translate nanotheranostics into the market, as well as their commercial impact.

Gold nanoprobes for multi loci assessment of multi-drug resistant tuberculosis.

Tuberculosis, still one of the leading human infectious diseases, reported 8.7 million new cases in 2011 alone. Also, the increasing rate of multidrug-resistant tuberculosis (MDRTB) and its treatment difficulties pose a serious public health threat especially in developing countries. Resistance to isoniazid and rifampicin, first line antibiotics, is commonly associated with point mutations in katG, inhA and rpoB genes of Mycobacterium tuberculosis complex (MTBC). Therefore, the development of cheap, fast and simple molecular methods to assess susceptibility profiles would have a huge impact in the capacity of early diagnosis and treatment of MDRTB. Gold nanoparticles functionalized with thiol-modified oligonucleotides (Au-nanoprobes) have shown the potential to provide a rapid and sensitive detection method for MTBC and single base mutations associated with antibiotic resistance, namely the characterization of the three most relevant codons in rpoB gene associated to rifampicin resistance. Here we extend the Au-nanoprobe approach towards discriminating specific mutations within inhA and rpoB genes in PCR amplified DNA from isolates. Using a multiplex PCR reaction for these two genes, it is possible to assess both loci in parallel, and extend the potential of the Au-nanoprobe method to MDRTB molecular characterization with special application in the most frequent Portuguese genotypes.

Isothermal DNA amplification coupled to Au-nanoprobes for detection of mutations associated to Rifampicin resistance in Mycobacterium tuberculosis.

BACKGROUND: Tuberculosis accounted for 8.7 million new cases in 2011 and continues to be one of the leading human infectious diseases. Burdensome is the increasing rate of multi-drug resistant tuberculosis (MDRTB) and the difficulties created for treatment and public health control programs, especially in developing countries. Resistance to rifampicin (RIF), a first line antibiotic, is commonly associated with point mutations within the rpoB gene of Mycobacterium tuberculosis (Mtb) whose detection is considered the best early molecular predictor for MDRTB. Gold nanoparticles functionalized with thiol-modified oligonucleotides (Au-nanoprobes) have shown the potential to provide a rapid and sensitive detection method for Mtb and single base alterations associated with antibiotic resistance, namely in rpoB gene associated to RIF resistance. RESULTS: We developed a strategy based on the isothermal amplification of sample DNA (LAMP) coupled to specific Au-nanoprobes capable of identifying members of the Mtb complex (MTBC) and discriminating specific mutations within the rpoB gene. Integration of LAMP and Au-nanoprobe assay allowed to detect MTBC member and identify mutations linked to RIF resistance. A total of 12 biological samples were tested and a 100% specificity and sensitivity was attained. CONCLUSIONS: There is an increasing demand for simple, fast and cheap methods for the molecular identification of Mtb and for the detection of molecular tags associated to drug resistance suitable for use at point-of-need. Here we describe such a method, that as the potential to get molecular diagnostic of tuberculosis to remote environments.

Children as carers: an integrative review.

OBJECTIVE: to undertake an integrative literature review on the issue of "Children as carers". This is an emerging topic in the provision of health care, but nevertheless has a low profile in the literature. METHODOLOGY: this study was based in a survey of nine databases of scientific articles, using as descriptor: child, young, caregivers, lay carer and nursing role, as well as the corresponding terms in Portuguese. 21 articles were analyzed. RESULTS: these were organized into six categories--factors which motivate the child to take on the role of caregiver; these children's characteristics; tasks performed; time spent in caring; consequences of providing care and the role of the nurse in partnership with these children and their families. CONCLUSION: the children as carers are a focus of attention relevant to nursing practice, this issue representing an opportunity for investigation in Portuguese-speaking countries, as no article was found on the subject in Portuguese. In addition, with this first study in Portuguese, a work of the creation of a bibliography is begun, allowing an awareness of the issue and the identification of ways to respond to the families involved, in line with their needs.

Children as carers: an integrative review / Crianças como cuidadoras: revisão integrativa / Niños como cuidadores: revisión integrativa

OBJECTIVE: to undertake an integrative literature review on the issue of "Children as carers". This is an emerging topic in the provision of health care, but nevertheless has a low profile in the literature. METHODOLOGY: this study was based in a survey of nine databases of scientific articles, using as descriptor: child, young, caregivers, lay carer and nursing role, as well as the corresponding terms in Portuguese. 21 articles were analyzed. RESULTS: these were organized into six categories - factors which motivate the child to take on the role of caregiver; these children's characteristics; tasks performed; time spent in caring; consequences of providing care and the role of the nurse in partnership with these children and their families. CONCLUSION: the children as carers are a focus of attention relevant to nursing practice, this issue representing an opportunity for investigation in Portuguese-speaking countries, as no article was found on the subject in Portuguese. In addition, with this first study in Portuguese, a work of the creation of a bibliography is begun, allowing an awareness of the issue and the identification of ways to respond to the families involved, in line with their needs.

OBJETIVO: realizar uma revisão bibliográfica integrativa do tema "Crianças como Cuidadoras". Trata-se de tema emergente na prestação de cuidados de saúde que, contudo, se mantém pouco visível na literatura. METODOLOGIA: baseou-se numa pesquisa sobre nove bases de dados de artigos científicos, utilizando-se como descritores: child, young, caregivers, lay carer and nursing role, bem como os correspondentes em português. Foram analisados 21 artigos. RESULTADOS: foram organizados em seis categorias: fatores que motivam a criança a assumir o papel de cuidadora; caraterísticas dessas crianças; tarefas desempenhadas; tempo passado a cuidar; consequências da prestação de cuidados e papel do enfermeiro em relação a essas crianças e suas famílias. CONCLUSÃO: as crianças como cuidadoras são um foco de atenção relevante para a prática de enfermagem, representando esse tema uma oportunidade de investigação nos países de língua portuguesa, já que não foi encontrado qualquer artigo em português sobre o mesmo. Além disso, com este primeiro estudo em língua portuguesa, inicia-se um trabalho de criação bibliográfica que permita a sensibilização para o tema e a identificação das respostas a dar às famílias envolvidas, de acordo com as suas necessidades.

OBJETIVO: realizar una revisión bibliográfica integrativa del tema "Niños como Cuidadores". Se Trata de un tema emergente en la prestación de atenciones de salud, que sin embargo se mantiene poco visible en la literatura. METODOLOGÍA: se basó en una investigación sobre nueve bases de datos de artículos científicos, utilizándose como descriptores: child, young, caregivers, lay carer y nursing role, así como los correspondientes en portugués. Fueron analizados 21 artículos. RESULTADOS: fueron organizados en seis categorías - factores que motivan el niño a asumir el papel de cuidador; características de esos niños; tareas desempeñadas; tiempo pasado a cuidar; consecuencias de la prestación de atenciones y papel del enfermero junto de esos niños y sus familias. CONCLUSIÓN: los niños como cuidadores son un foco de atención relevante para la práctica de enfermería, representando ese tema una oportunidad de averiguación en los países de idioma portugués, ya que no fue encontrado cualquier artículo en portugués sobre el mismo. Además, con éste primer estudio en idioma portugués, se inicia un trabajo de creación bibliográfica que permita la sensibilización para el tema y la identificación de las respuestas a dar a las familias envueltas, de acuerdo con sus necesidades.

Viral infections in workers in hospital and research laboratory settings: a comparative review of infection modes and respective biosafety aspects.

OBJECTIVES: To compare modes and sources of infection and clinical and biosafety aspects of accidental viral infections in hospital workers and research laboratory staff reported in scientific articles. METHODS: PubMed, Google Scholar, ISI Web of Knowledge, Scirus, and Scielo were searched (to December 2008) for reports of accidental viral infections, written in English, Portuguese, Spanish, or German; the authors' personal file of scientific articles and references from the articles retrieved in the initial search were also used. Systematic review was carried out with inclusion criteria of presence of accidental viral infection's cases information, and exclusion criteria of absence of information about the viral etiology, and at least probable mode of infection. RESULTS: One hundred and forty-one scientific articles were obtained, 66 of which were included in the analysis. For arboviruses, 84% of the laboratory infections had aerosol as the source; for alphaviruses alone, aerosol exposure accounted for 94% of accidental infections. Of laboratory arboviral infections, 15.7% were acquired percutaneously, whereas 41.6% of hospital infections were percutaneous. For airborne viruses, 81% of the infections occurred in laboratories, with hantavirus the leading causative agent. Aerosol inhalation was implicated in 96% of lymphocytic choriomeningitis virus infections, 99% of hantavirus infections, and 50% of coxsackievirus infections, but infective droplet inhalation was the leading mode of infection for severe acute respiratory syndrome coronavirus and the mucocutaneous mode of infection was involved in the case of infection with influenza B. For blood-borne viruses, 92% of infections occurred in hospitals and 93% of these had percutaneous mode of infection, while among laboratory infections 77% were due to infective aerosol inhalation. Among blood-borne virus infections there were six cases of particular note: three cases of acute hepatitis following hepatitis C virus infection with a short period of incubation, one laboratory case of human immunodeficiency virus infection through aerosol inhalation, one case of hepatitis following hepatitis G virus infection, and one case of fulminant hepatitis with hepatitis B virus infection following exposure of the worker's conjunctiva to hepatitis B virus e antigen-negative patient saliva. Of the 12 infections with viruses with preferential mucocutaneous transmission, seven occurred percutaneously, aerosol was implicated as a possible source of infection in two cases, and one atypical infection with Macacine herpesvirus 1 with fatal encephalitis as the outcome occurred through a louse bite. One outbreak of norovirus infection among hospital staff had as its probable mode of infection the ingestion of inocula spread in the environment by fomites. CONCLUSIONS: The currently accepted and practiced risk analysis of accidental viral infections based on the conventional dynamics of infection of the etiological agents is insufficient to cope with accidental viral infections in laboratories and to a lesser extent in hospitals, where unconventional modes of infection are less frequently present but still have relevant clinical and potential epidemiological consequences. Unconventional modes of infection, atypical clinical development, or extremely severe cases are frequently present together with high viral loads and high virulence of the agents manipulated in laboratories. In hospitals by contrast, the only possible association of atypical cases is with the individual resistance of the worker. Current standard precaution practices are insufficient to prevent most of the unconventional infections in hospitals analyzed in this study; it is recommended that special attention be given to flaviviruses in these settings.