Nanodiamond-Based Composite Structures for Biomedical Imaging and Drug Delivery.
01 Feb 2015-Journal of Nanoscience and Nanotechnology (J Nanosci Nanotechnol)-Vol. 15, Iss: 2, pp 959-971
TL;DR: A particular focus of the review is core/shell structures of nanodiamond surrounded by porous silica shells, which demonstrate a remarkable increase in drug loading efficiency; as well as nanod diamonds decorated with carbon dots, which have excellent potential as bioimaging probes.
Abstract: Nanodiamond particles are widely recognized candidates for biomedical applications due to their excellent biocompatibility, bright photoluminescence based on color centers and outstanding photostability. Recently, more complex architectures with a nanodiamond core and an external shell or nanostructure which provides synergistic benefits have been developed, and their feasibility for biomedical applications has been demonstrated. This review is aimed at summarizing recent achievements in the fabrication and functional demonstrations of nanodiamond-based composite structures, along with critical considerations that should be taken into account in the design of such structures from a biomedical point of view. A particular focus of the review is core/shell structures of nanodiamond surrounded by porous silica shells, which demonstrate a remarkable increase in drug loading efficiency; as well as nanodiamonds decorated with carbon dots, which have excellent potential as bioimaging probes. Other combinations are also considered, relying on the discussed inherent properties of the inorganic materials being integrated in a way to advance inorganic nanomedicine in the quest for better health-related nanotechnology.
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TL;DR: The design and applications of various kinds of long-lived emissive probes for bioimaging and biosensing via time-resolved photoluminescence techniques are summarized and the imaging contrast and sensing sensitivity are remarkably improved.
Abstract: In this Review article, we systematically summarize the design and applications of various kinds of long-lived emissive probes for bioimaging and biosensing via time-resolved photoluminescence techniques The probes reviewed, including lanthanides, transition-metal complexes, organic dyes, carbon and silicon nanoparticles, metal clusters, and persistent phosphores, exhibit longer luminescence lifetimes than that of autofluorescence from biological tissue and organs When these probes are internalized into living cells or animals, time-gated photoluminescence imaging selectively collects long-lived signals for intensity analysis, while photoluminescence lifetime imaging reports the decay details of each pixel Since the long-lived signals are differentiated from autofluorescence in the time domain, the imaging contrast and sensing sensitivity are remarkably improved The future prospects and challenges in this rapidly growing field are addressed
560 citations
TL;DR: This review comparing the toxicity and the stability of different nanoprobes shows that optimized silicon quantum dots (Si QDs) and fluorescent nanodiamonds (FNDs) show almost no photobleaching in a physiological environment.
Abstract: Fluorescence bioimaging is a powerful, versatile, method for investigating, both in vivo and in vitro, the complex structures and functions of living organisms in real time and space, also using super-resolution techniques. Being poorly invasive, fluorescence bioimaging is suitable for long-term observation of biological processes. Long-term detection is partially prevented by photobleaching of organic fluorescent probes. Semiconductor quantum dots, in contrast, are ultrastable, fluorescent contrast agents detectable even at the single nanoparticle level. Emission color of quantum dots is size dependent and nanoprobes emitting in the near infrared (NIR) region are ideal for low back-ground in vivo imaging. Biocompatibility of nanoparticles, containing toxic elements, is debated. Recent safety concerns enforced the search for alternative ultrastable luminescent nanoprobes. Most recent results demonstrated that optimized silicon quantum dots (Si QDs) and fluorescent nanodiamonds (FNDs) show almost no photobleaching in a physiological environment. Moreover in vitro and in vivo toxicity studies demonstrated their unique biocompatibility. Si QDs and FNDs are hence ideal diagnostic tools and promising non-toxic vectors for the delivery of therapeutic cargos. Most relevant examples of applications of Si QDs and FNDs to long-term bioimaging are discussed in this review comparing the toxicity and the stability of different nanoprobes.
214 citations
TL;DR: ND particles structure, strategies for surface modification, electrokinetic properties of NDs in suspensions, and a brief overview of the relevant bioapplications are discussed.
Abstract: Diamond has outstanding bulk properties such as super hardness, chemical inertness, biocompatibility, luminescence, to name just a few. In the nanoworld, in order to exploit these outstanding bulk properties, the surfaces of nanodiamond (ND) particles must be accordingly engineered for specific applications. Modification of functional groups on the ND's surface and the corresponding electrostatic properties determine their colloidal stability in solvents, formation of photonic crystals, controlled adsorption and release of cargo molecules, conjugation with biomolecules and polymers, and cellular uptake. The optical activity of the luminescent color centers in NDs depends on their proximity to the ND's surface and surface termination. In order to engineer the ND surface, a fundamental understanding of the specific structural features and sp(3)-sp(2) phase transformations on the surface of ND particles is required. In the case of ND particles produced by detonation of carbon containing explosives (detonation ND), it should also be taken into account that its structure depends on the synthesis parameters and subsequent processing. Thus, for development of a strategy of surface modification of detonation ND, it is imperative to know details of its production. In this review, the authors discuss ND particles structure, strategies for surface modification, electrokinetic properties of NDs in suspensions, and conclude with a brief overview of the relevant bioapplications.
146 citations
TL;DR: The strategies for further improving drug delivery and imaging by carbon nanomaterials are reviewed, such as inducing endothelial leakiness as well as applying artificial intelligence toward designing optimal nanoparticle-based drug combination delivery.
Abstract: Nanomaterials have the potential to improve how patients are clinically treated and diagnosed. While there are a number of nanomaterials that can be used toward improved drug delivery and imaging, how these nanomaterials confer an advantage over other nanomaterials, as well as current clinical approaches is often application or disease specific. How the unique properties of carbon nanomaterials, such as nanodiamonds, carbon nanotubes, carbon nanofibers, graphene, and graphene oxides, make them promising nanomaterials for a wide range of clinical applications are discussed herein, including treating chemoresistant cancer, enhancing magnetic resonance imaging, and improving tissue regeneration and stem cell banking, among others. Additionally, the strategies for further improving drug delivery and imaging by carbon nanomaterials are reviewed, such as inducing endothelial leakiness as well as applying artificial intelligence toward designing optimal nanoparticle-based drug combination delivery. While the clinical application of carbon nanomaterials is still an emerging field of research, there is substantial preclinical evidence of the translational potential of carbon nanomaterials. Early clinically trial studies are highlighted, further supporting the use of carbon nanomaterials in clinical applications for both drug delivery and imaging.
130 citations
TL;DR: A rational review of the development of fluorescent inorganic nanoparticles in the area of optical sensing can be found in this paper, where the application aspects for use as optical sensing receptors are highlighted with the focus on the possible sensing mechanisms, the crucial optimisation processes during the development, and the options available for data analysis on the signals recorded from the optical sensors.
Abstract: Fluorescence is one of the techniques adopted for a large number of optical bioassays and chemical sensing probes. The key driving motivation is basically governed by the ease of operational process, simple setup, high sensitivity, online throughput readouts, and most importantly the well understood principles behind fluorescence spectroscopy. Typically, an optical sensor adopting this technique requires sensing receptors that will interact with an analyte, subsequently causing a change that can be correlated to the identity and/or quantity of the analyte of interest. For this instance, various fluorophores are suitable to be used as the receptor and the most recent class is the fluorescent inorganic nanoparticles; portraying similar fluorescence properties to conventional organic dyes, but having special features and nature that are unique by themselves. This paper offers a rational review particularly on the development of these fluorescent inorganic nanoparticles in the area of optical sensing, excluding the coverage on fluorescent nanoparticles made of organic based fluorophores. It will cover the fundamental properties, basic methods of synthesis, engineering features, and the available characterisation options of the nanoparticles. Specifically, the application aspects for use as optical sensing receptors is highlighted with the focus on the possible sensing mechanisms, the crucial optimisation processes during the development of a sensor, and the options available for data analysis on the signals recorded from the optical sensors. Various successful demonstrations of the utilisation of such fluorescent nanoparticles for detecting different analytes will be given in this review. This paper offers a good insight on real practical ways to utilise the unique optical properties of fluorescent inorganic nanoparticles for sensing applications.
118 citations