One of the most serious current global threats is the emergence of bacteria that have built resistance to our most powerful available drugs due to drug overuse. As a result, there is an urgency for the discovery of new antimicrobial agents to fight resistance of bacteria. In recent years, various types of nanoparticles and nanoclusters have been researched for this purpose. The advantage of employing nanoparticles in bacteria killing is that the properties of nanoparticles can be customized by altering nanoparticle physicochemical properties, enabling the tuning of mechanisms that bacteria can be killed. In this paper we present our recent findings in our investigation of the antibacterial properties of 5‑mercapto-2-nitrobenzoic acid coated silver nanoclusters against a wide range of pathogenic bacterial species.
The design and synthesis of DNA and RNA sensors are critical towards the improvement of early diagnosis of various diseases. In this paper, we discuss our recent efforts to construct a sensor based on upconversion nanoparticles (UCNPs) and graphene oxide (GO) for the detection of synthetic viral oligonucleotide targets.
The ability of DNA functionalised gold nanoparticles (AuNPs) to detect specific targets in vitro and in vivo has led to their development as suitable tools for sensing applications. However, endosomal entrapment is a common barrier in various nanoparticle delivery approaches. In this work, we present a new design strategy with the aim to enhance endosomal escape of DNA-coated AuNPs via the incorporation of a peptide that has been found to promote effective escape within cells. AuNPs are firstly modified with thiol terminated DNA strands followed by further surface functionalisation with cysteine terminated peptides. We show that optimized loading of peptides following DNA nanoparticle functionalisation of nanoparticles is feasible. DNA-peptide-coated AuNP hybrids show similar stability towards degradation by endocellular enzymes and similar specificity towards the detection of specific mRNA targets.
Recently DNA-coated gold nanoparticles have emerged as ideal tools for the detection of mRNA in cells using dye modified oligonucleotides. However, the tracking of the gold core has been hindered by the small size of the particle core. In this work we utilize a home built set up and 43 nm DNA-coated spherical gold nanoparticles for the simultaneous imaging of mRNA detection using fluorescence microscopy and the gold nanoparticle core using two photon photoluminescence (TPPL).
In this paper we investigate how the density of oligonucleotides around spherical 15 nm gold nanoparticles (AuNPs) influences their stability against degradation by DNase I. We show that a significant decrease in the number of oligonucleotides attached to the AuNP surface is directly correlated with an increase in the DNA degradation by DNase I. Our experimental observations suggest that a close packing of oligonucleotides into a 3d arrangement at the surface of AuNPs endows the probes with the necessary stability required for their use in intracellular applications.
In this paper we present chemical methods developed in our laboratory to synthesize nanoparticles for biomedical and imaging applications. We show that branched gold nanoparticles can be used for imaging applications whereas gold nanorods can be successfully coated with materials such as silica making them ideal for further bio-functionalization.
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