Nanotechnology has emerged as a {"}disruptive technology{"} that may provide researchers with new and innovative ways to diagnose, treat and monitor cancer. In fact, nanomedicine approaches have delivered several strategies, such as new imaging agents, real-time assessments of therapeutic and surgical efficacy, multifunctional, targeted devices capable of bypassing biological barriers to target and silence specific pathways in tumours. Of particular interest, has been the increased capability to deliver multiple therapeutic agents directly to bulk cancer cells and cancer stem cells that play a critical role in cancer growth and metastasis. These multifunctional targeted nanoconjugates are also capable of avoiding cancer resistance and monitor predictive molecular changes that open the path for preventive action against pre-cancerous cells, minimizing costs and incidence of relapses. A myriad of nanoconjugates with effective silencing and site-targeting moieties can be developed by incorporating a diverse selection of targeting, diagnostic, and therapeutic components. A discussion of the integrative effort of nanotechnology systems with recent developments of biomolecular interactions in cancer progression is clearly required. Here, we will update the state of the art related to the development and applications of nanoscale platforms and novel biomolecular players in cancer diagnosis, imaging and treatment.

Over the past decade, the capability of double-stranded RNAs to interfere with gene expression has driven new therapeutic approaches. Since small interfering RNA (siRNAs, 21 base pair double-stranded RNA) was shown to be able to elicit RNA interference (RNAi), efforts were directed toward the development of efficient delivery systems to preserve siRNA bioactivity throughout the delivery route, from the administration site to the target cell. Here we provide evidence of RNAi triggering, specifically silencing c-myc protooncogene, via the synthesis of a library of novel multifunctional gold nanoparticles (AuNPs). The efficiency of the AuNPs is demonstrated using a hierarchical approach including three biological systems of increasing complexity: in vitro cultured human cells, in vivo invertebrate (freshwater polyp, Hydra), and in vivo vertebrate (mouse) models. Our synthetic methodology involved fine-tuning of multiple structural and functional moieties. Selection of the most active functionalities was assisted step-by-step through functional testing that adopted this hierarchical strategy. Merging these chemical and biological approaches led to a safe, nonpathogenic, self-tracking, and universally valid nanocarrier that could be exploited for therapeutic RNAi.

Tuberculosis (TB) remains one of the most serious infectious diseases in the world and the rate of new cases continues to increase. The development of cheap and simple methodologies capable of identifying TB causing agents belonging to the Mycobacterium tuberculosis Complex (MTBC), at point-of-need, in particular in resource-poor countries where the main TB epidemics are observed, is of paramount relevance for the timely and effective diagnosis and management of patients. TB molecular diagnostics, aimed at reducing the time of laboratory diagnostics from weeks to days, still require specialised technical personnel and labour intensive methods. Recent nanotechnology-based systems have been proposed to circumvent these limitations. Here, we report on a paper-based platform capable of integrating a previously developed Au-nanoprobe based MTBC detection assay-we call it {"}Gold on Paper{"}. The Au-nanoprobe assay is processed and developed on a wax-printed microplate paper platform, allowing unequivocal identification of MTBC members and can be performed without specialised laboratory equipment. Upon integration of this Au-nanoprobe colorimetric assay onto the 384-microplate, differential colour scrutiny may be captured and analysed with a generic {"}smartphone{"} device. This strategy uses the mobile device to digitalise the intensity of the colour associated with each colorimetric assay, perform a Red Green Blue (RGB) analysis and transfer relevant information to an off-site lab, thus allowing for efficient diagnostics. Integration of the GPS location metadata of every test image may add a new dimension of information, allowing for real-time epidemiologic data on MTBC identification.

Aims: Our aim is to explore whether gold nanoparticles (AuNPs) functionalized with a carboxylated polyethylene glycol (PEG) and protamine (AuNP@PEG@Prot) can modulate - enhance or restrain - DNA condensation, altering DNA conformation and inducing structural changes. Understanding how these nanoconjugates modulate DNA structure, size and shape of DNA condensates, and enable control over the resulting 3D structures is of major biological and therapeutic importance. Materials & methods: Citrate-AuNPs were covered with a dense layer of a hetero-functional octa(ethylene glycol) (SH-EG(8)-COOH). Conjugation of protamine to the AuNP@PEG was achieved by taking advantage of the carboxylated surface previously generated on the surface of the NP and the remaining amino groups from the protamine, using carbodiimide and N-hydroxysulfosuccinimide coupling reactions. Results & conclusion: AuNP@PEG@Prot modulates the structure and topology of DNA, not only for condensation, but also for decondensation, via formation of higher quantities of dimers and multimers, when compared with AuNP@PEG and free protamine.

The surface chemistry of gold nanoparticles (AuNPs) plays a critical role in the self-assembly of thiolated molecules and in retaining the biological function of the conjugated biomolecules. According to the well-established gold-thiol interaction the undefined ionic species on citrate-reduced gold nanoparticle surface can be replaced with a self-assembled monolayer of certain thiolate derivatives and other biomolecules. Understanding the effect of such derivatives in the functionalization of several types of biomolecules, such as PEGs, peptides or nucleic acids, has become a significant challenge. Here, an approach to attach specific biomolecules to the AuNPs (∼14 nm) surface is presented together with a study of their effect in the functionalization with other specific derivatives. The effect of biofunctional spacers such as thiolated poly(ethylene glycol) (PEG) chains and a positive peptide, TAT, in dsRNA loading on AuNPs is reported. Based on the obtained data, we hypothesize that loading of oligonucleotides onto the AuNP surface may be controlled by ionic and weak interactions positioning the entry of the oligo through the PEG layer. We demonstrate that there is a synergistic effect of the TAT peptide and PEG chains with specific functional groups on the enhancement of dsRNA loading onto AuNPs.

Measuring RNA synthesis and, when required, the level of inhibition, is crucial towards the development of practical strategies to evaluate silencing efficiency of gene silencing approaches. We developed a direct method to follow RNA synthesis in real time based on gold nanoparticles (AuNPs) functionalized with a fluorophore labeled hairpin-DNA, i.e. gold-nanobeacon (Au-nanobeacon). Under hairpin configuration, proximity to gold nanoparticles leads to fluorescence quenching; hybridization to a complementary target restores fluorescence emission due to the Au-nanobeacons' conformational reorganization that causes the fluorophore and the AuNP to part from each other, yielding a quantitative response. With this reporter Au-nanobeacon we were able to measure the rate of in vitro RNA synthesis ( 10.3. fmol of RNA per minute). Then, we designed a second Au-nanobeacon targeting the promoter sequence (inhibitor) so as to inhibit transcription whilst simultaneously monitor the number of promoters being silenced. Using the two Au-nanobeacons in the same reaction mixture, we are capable of quantitatively assess in real time the synthesis of RNA and the level of inhibition.The biosensor concept can easily be extended and adapted to situations when real-time quantitative assessment of RNA synthesis and determination of the level of inhibition are required. In fact, this biosensor may assist the in vitro evaluation of silencing potential of a given sequence to be later used for in vivo gene silencing.

The development of rapid detection assays for malaria diagnostics is an area of intensive research, as the traditional microscopic analysis of blood smears is cumbersome and requires skilled personnel. Here, we describe a simple and sensitive immunoassay that successfully detects malaria antigens in infected blood cultures. This homogeneous assay is based on the fluorescence quenching of cyanine 3B (Cy3B)-labeled recombinant Plasmodium falciparum heat shock protein 70 (PfHsp70) upon binding to gold nanoparticles (AuNPs) functionalized with an anti-Hsp70 monoclonal antibody. Upon competition with the free antigen, the Cy3B-labeled recombinant PfHsp70 is released to solution resulting in an increase of fluorescence intensity. Two types of AuNP-antibody conjugates were used as probes, one obtained by electrostatic adsorption of the antibody on AuNPs surface and the other by covalent bonding using protein cross-linking agents. In comparison with cross-linked antibodies, electrostatic adsorption of the antibodies to the AuNPs surfaces generated conjugates with increased activity and linearity of response, within a range of antigen concentration from 8.2 to 23.8 μg.mL(-1). The estimated LOD for the assay is 2.4 μg.mL(-1) and the LOQ is 7.3 μg.mL(-1). The fluorescence immunoassay was successfully applied to the detection of antigen in malaria-infected human blood cultures at a 3% parasitemia level, and is assumed to detect parasite densities as low as 1,000 parasites.μL(-1).

Tuberculosis remains one of the most serious infectious diseases worldwide requiring new tools to circumvent current molecular diagnostics limitations. Nanodiagnostics, i.e. nanotechnology based diagnostics, may do just that by decreasing the time needed for the molecular characterisation of the infecting agent, and allowing for miniaturisation and portability for point-of-need adapted to remote regions without suitable lab equipment.

In the last decade the use of nanomaterials has been having a great impact in biosensing. In particular, the unique properties of noble metal nanoparticles have allowed for the development of new biosensing platforms with enhanced capabilities in the specific detection of bioanalytes. Noble metal nanoparticles show unique physicochemical properties (such as ease of functionalization via simple chemistry and high surface-to-volume ratios) that allied with their unique spectral and optical properties have prompted the development of a plethora of biosensing platforms. Additionally, they also provide an additional or enhanced layer of application for commonly used techniques, such as fluorescence, infrared and Raman spectroscopy. Herein we review the use of noble metal nanoparticles for biosensing strategies-from synthesis and functionalization to integration in molecular diagnostics platforms, with special focus on those that have made their way into the diagnostics laboratory.

Nanotechnology provides new tools for gene expression analysis that allow for sensitive and specific characterization of prognostic signatures related to cancer. Cancer is a multigenic complex disease where multiple gene loci contribute to the phenotype. The ability to simultaneously monitor differential expression originating from each locus allows for a more accurate indication of degree of cancerous activity than either locus alone. Metal nanoparticles have been widely used as labels for in vitro identification and quantification of target sequences. Here we describe the synthesis of nanoparticles with different noble metal compositions in an alloy format that are then functionalized with thiol-modified ssDNA (nanoprobes). We also show how to use such nanoprobes in a non-cross-linking colorimetric method for the direct detection and quantification of specific mRNA targets, without the need for enzymatic amplification or reverse transcription steps. The different metals in the alloy provide for distinct absorption spectra due to their characteristic plasmon resonance peaks. The color multiplexing allows for simultaneous identification of several different mRNA targets involved in cancer development. Comparison of the absorption spectra of the nanoprobes mixtures taken before and after induced aggregation of metal nanoparticles allows to both identify and quantify each mRNA target. We describe the use of gold and gold:silver-alloy nanoprobes for the development of the non-cross-linking method to detect a specific BCR-ABL fusion gene (e.g., e1a2 and e14a2) mRNA target associated with chronic myeloid leukemia (CML) using 10 ng μL -1 of unamplified total human RNA. This simple methodology takes less than 50 min to complete after total RNA extraction with comparable specificity and sensitivity to the more commonly used methods.

A strategy for the development of novel antimicrobials is to combine the stability and pleiotropic effects of inorganic compounds with the specificity and efficiency of organic compounds, such as antibiotics. Here we report on the use of gold:silver-alloy (Au:Ag-alloy) nanoparticles, obtained via a single-step citrate co-reduction method, combined to conventional antibiotics to enhance their antimicrobial effect on bacteria. Addition of the alloy nanoparticles considerably decreased the dose of antibiotic necessary to show antimicrobial effect, both for bacterial cells growing in rich medium in suspension and for bacterial cells resting in a physiological buffer on a humid cellulose surface. The observed effect was more pronounced than the sum of the individual effects of the nanoparticles and antibiotic. We demonstrate the enhancement effect of Au:Ag-alloy nanoparticles with a size distribution of 32.5±7.5nm mean diameter on the antimicrobial effect of (i) kanamycin onEscherichia coli(Gram-negative bacterium), and (ii) a β-lactam antibiotic on both a sensitive and resistant strain ofStaphylococcus aureus(Gram-positive bacterium). Together, these results may pave the way for the combined use of nanoparticle–antibiotic conjugates towards decreasing antibiotic resistance currently observed for certain bacteria and conventional antibiotics.

Light has always fascinated mankind and since the beginning of recorded history it has been both a subject of research and a tool for investigation of other phenomena. Today, with the advent of nanotechnology, the use of light has reached its own dimension where light-matter interactions take place at wavelength and subwavelength scales and where the physical/chemical nature of nanostructures controls the interactions. This is the field of nanophotonics which allows for the exploration and manipulation of light in and around nanostructures, single molecules, and molecular complexes. What is more is the use of nanophotonics in biomolecular interactionsnanobiophotonicshas prompt for a plethora of molecular diagnostics and therapeutics making use of the remarkable nanoscale properties. In this paper, we shall focus on the uses of nanobiophotonics for molecular diagnostics involving specific sequence characterization of nucleic acids and for gene delivery systems of relevance for therapy strategies. The use of nanobiophotonics for the combined diagnostics/therapeutics (theranostics) will also be addressed, with particular focus on those systems enabling the development of safer, more efficient, and specific platforms. Finally, the translation of nanophotonics for theranostics into the clinical setting will be discussed.

Nanotechnology has prompted new and improved materials for biomedical applications with particular emphasis in therapy and diagnostics. Special interest has been directed at providing enhanced molecular therapeutics for cancer, where conventional approaches do not effectively differentiate between cancerous and normal cells; that is, they lack specificity. This normally causes systemic toxicity and severe and adverse side effects with concomitant loss of quality of life. Because of their small size, nanoparticles can readily interact with biomolecules both at surface and inside cells, yielding better signals and target specificity for diagnostics and therapeutics. This way, a variety of nanoparticles with the possibility of diversified modification with biomolecules have been investigated for biomedical applications including their use in highly sensitive imaging assays, thermal ablation, and radiotherapy enhancement as well as drug and gene delivery and silencing. Here, we review the available noble metal nanoparticles for cancer therapy, with particular focus on those already being translated into clinical settings.

Sistema para detección, identificación y cuantificación en material biológico, compuesto por una o más fuentes de luz (1) combinado con uno o más fotosensores ópticos (6 y 7) y diversos componentes electrónicos (4), necesarios para obtener/procesar la señal emitida caracterizado por: a) La fuente de luz (1), pulsada (2) o no, compuesta de láseres de estado sólido de baja energía o diodos emisores de luz, cuyo rango de longitud de onda está localizado entre 400 y 800 nm con una intensidad de luminosidad controlable que varía entre los valores de 0.01 mW/cm 2 y 100 mW/cm 2 ; b) El fotosensor, sencillo (6 y 7a) y (6 y 7b) o integrado (6, 4 y 7) compuesto de películas delgadas de silicio amorfo o nanocristalino o microcristalino y/o por semiconductores de cerámica tales como IGZO, IAgZO, SnZIO, GZIO, CuOIZ, GITO, entre otros, y basado en estructuras tipo pi'ii'n o MIS, que funciona en un rango de longitudes de onda desde el infrarrojo hasta el ultravioleta, y prové una información cualitativa y cuantitativa basada en la hibridización especifica y selectiva de sondas funcionalizadas con nanopartículas de metal; c) Siendo provista la eliminación del sistema a través de una fuente de energía convencional o a través de baterías fotovoltaicas, que dan portabilidad al sistema, siendo focalizada la luz emitida sobre la muestra, preferiblemente utilizando microlentes, siendo la muestra o muestras no fijadas físicamente al sensor o sensores, colocando la muestra biológica referida (5) sobre el lado opuesto (6) del sustrato donde se deposita el fotosensor (6 y 7).

We present a new approach for real-time monitoring of PCR amplification of a specific sequence from the human c-MYC proto-oncogene using a Ta(2)O(5) electrolyte-insulator-semiconductor (EIS) sensor. The response of the fabricated EIS sensor to cycle DNA amplification was evaluated and compared to standard SYBR-green fluorescence incorporation, showing it was possible to detect DNA concentration variations with 30 mV/μM sensitivity. The sensor's response was then optimized to follow in real-time the PCR amplification of c-MYC sequence from a genomic DNA sample attaining an amplification profile comparable to that of a standard real-time PCR. Owing to the small size, ease of fabrication and low-cost, the developed Ta(2)O(5) sensor may be incorporated onto a microfluidic device and then used for real-time PCR. Our approach may circumvent the practical and economical obstacles posed by current platforms that require an external fluorescence detector difficult to miniaturize and incorporate into a lab-on-chip system.

We report a new strategy that combines a Forster Resonance Energy Transfer (FRET) based spectral codification tool with a single base extension (SBE) reaction for rapid and medium-throughput analysis of single nucleotide polymorphisms (SNPs). This strategy is based on the spectral codification - a donor (fluorophore labeled probe complementary to the region adjacent to an SNP) is used to induce specific FRET signatures from an acceptor fluorophore revealing the SNP variant. Using an SBE reaction and differently labeled ddNTPs, we can directly question each donor probe and retrieve information about which allele variant is present at that locus. The potential of the method is demonstrated by application to simultaneous questioning of two loci in the same reaction tube. Following calibration with all possible combinations of FRET pairs, an evaluation algorithm was calibrated so as to optimize base calling and allow unequivocal allele scoring with more than 80% confidence (for two simultaneous loci being questioned, one homo-and one heterozygous). In conclusion, this spectral codification approach may constitute a solution towards increasing throughput capability of single base extension based assays.

Nanotechnology has prompted researchers to develop new and improved materials aimed at biomedical applications with particular emphasis in diagnostics and therapy. Special interest has been directed at providing enhanced biomolecular diagnostics, including SNP detection gene expression profiles and biomarker characterisation. These strategies have focused on the development of nanoscale devices and platforms that can be used for single molecule characterisation of nucleic acid, DNA or RNA, and protein at an increased rate when compared to traditional techniques. Also, several advances have been reported on DNA analysis in real time, at both high resolution and very high throughputs, suitable for biomedical diagnostics. Here, we shall provide a review of available nanotechnology-based platforms for biomolecular recognition, and their application to molecular diagnostics and genome analysis, with emphasis on the use of noble metal nanoparticles for simple and specific analysis systems. Particular focus will be put on those already being translated into clinical settings. This article is part of a Special Issue entitled: Clinical Proteomics.

In this paper we report on the fabrication and performance of a portable and low cost optoelectronic platform integrating a double color tuned light emitting diode as light source, an amorphous/nanocrystalline silicon photodetector with a flat spectral response in the wavelength range from 520. nm to 630. nm and integrated electronic for signal acquisition and conditioning constituted by current to voltage converter, a filter and an amplification stage, followed by an analog to digital converter, with appropriate software for full automation to minimize human error. Incorporation of the double color tuned light emitting diode provides for a simple yet innovative solution to signal acquisition independently from the light intensity and/or solution concentration, while considerably decreasing production costs. Detection based on Au-nanoprobes constitutes the biorecognition step and allowed identification of specific sequences of Mycobacterium tuberculosis complex, namely Mycobacterium bovis and M. tuberculosis in biological samples.