New insight into the synthesis, morphological architectures and biomedical applications of elemental selenium nanostructures.

Selenium nanoparticles have been shown to be versatile in their applications by being used in catalysis, solar cells, electronic devices and especially in medical applications such as antiviral, anticancer, antitumor and antibacterial agents in different concentrations. They have also shown enhanced drug and gene delivery by conjugating with drug molecules and showing high synergistic effects. After realising their usefulness in the biomedical field, we have made a sincere effort to correlate and consolidate the recent developments made in their synthesis methods, structural features and biological applications. This review paper highlights the three preparation methods, being the chemical, physical and biological approaches. The variation in the different techniques employed for synthesis and the different parameters and process conditions dictating the size and morphology are discussed. The importance and influence of various reducing agents used in the chemical method, pulsed laser ablation technique in the physical method and green plant extract microorganism in the biological approach have been explored. The detailed structural features of trigonal crystalline structures, with different nanoscaled morphologies such as nano spheres, rods, wires, tubes and belts have also been explored. An overview of selenium nanoparticle activity in various biomedical applications such as anticancer, antioxidant, antiviral, antibacterial, antifungal, antiparasitic, and antidiabetics is discussed.

Graphene-semiconductor nanocomposites for cancer phototherapy.

Being a carbon-based hybrid, graphene-semiconductor composites have attracted considerable attention in recent decades owing to their potential features such as high photosensitivity, extended light absorption, and effective separation of charge carriers, thus have been regarded as a promising platform for environmental and biomedical applications, respectively. In this mini-review, we first summarized the recent advancements in the development of graphene-based semiconductor nanocomposites via sol-gel, solution mixing, in situ growth, hydrothermal, and solvothermal approaches, and then comprehensively reviewed their potential light activated cancer phototherapeutic applications. Finally, we rationally analyze the current challenges and new perspectives for the future development of more effective phototherapeutic nanoagents. We hope to offer enriched information to harvest the utmost fascinating properties of graphene as a platform to construct efficient graphene/semiconductor hybrids for cancer phototherapy.

Lab-On-A-Chip for the Development of Pro-/Anti-Angiogenic Nanomedicines to Treat Brain Diseases.

There is a huge demand for pro-/anti-angiogenic nanomedicines to treat conditions such as ischemic strokes, brain tumors, and neurodegenerative diseases such as Alzheimer's and Parkinson's. Nanomedicines are therapeutic particles in the size range of 10-1000 nm, where the drug is encapsulated into nano-capsules or adsorbed onto nano-scaffolds. They have good blood-brain barrier permeability, stability and shelf life, and able to rapidly target different sites in the brain. However, the relationship between the nanomedicines' physical and chemical properties and its ability to travel across the brain remains incompletely understood. The main challenge is the lack of a reliable drug testing model for brain angiogenesis. Recently, microfluidic platforms (known as "lab-on-a-chip" or LOCs) have been developed to mimic the brain micro-vasculature related events, such as vasculogenesis, angiogenesis, inflammation, etc. The LOCs are able to closely replicate the dynamic conditions of the human brain and could be reliable platforms for drug screening applications. There are still many technical difficulties in establishing uniform and reproducible conditions, mainly due to the extreme complexity of the human brain. In this paper, we review the prospective of LOCs in the development of nanomedicines for brain angiogenesis-related conditions.

Tumor-on-a-chip platforms for assessing nanoparticle-based cancer therapy.

Cancer has become the most prevalent cause of deaths, placing a huge economic and healthcare burden worldwide. Nanoparticles (NPs), as a key component of nanomedicine, provide alternative options for promoting the efficacy of cancer therapy. Current conventional cancer models have limitations in predicting the effects of various cancer treatments. To overcome these limitations, biomimetic and novel 'tumor-on-a-chip' platforms have emerged with other innovative biomedical engineering methods that enable the evaluation of NP-based cancer therapy. In this review, we first describe cancer models for evaluation of NP-based cancer therapy techniques, and then present the latest advances in 'tumor-on-a-chip' platforms that can potentially facilitate clinical translation of NP-based cancer therapies.

Developing Antitumor Magnetic Hyperthermia: Principles, Materials and Devices.

BACKGROUND AND OBJECTIVE: Methods of local or loco-regional anticancer treatment are of the utmost importance because the therapeutic 'power' is applied directly to the disease site. Consequently, general toxicity is minimized. Hyperthermia, that is, a sustained increase of intratumoral temperature up to 45oC, has been investigated as a perspective treatment modality alone and/or in combination with ionizing radiation or chemotherapy. Still, the surrounding tissues can be damaged by the external heat. METHOD: Development of new materials and devices gave rise to methods of inducing hyperthermia by a high frequency magnetic or electromagnetic field applied to the tumor with exogenous nanosized particles captured within it. The idea of this approach is the release of local heat in the vicinity of the magnetic nanoparticle in a time-varying magnetic field due to transfer of external magnetic field energy into the heat. Therefore, tumor cells are heated whereas the peritumoral non-malignant tissues are spared. RESULTS: This review analyzes recent advances in understanding physical principles that underlie magnetic hyperthermia as well as novel approaches to obtain nanoparticles with optimized physico-chemical, toxicological and tumoricidal properties. Special focus is made on the construction of devices for therapeutic purposes. CONCLUSION: The review covers recent patents and general literature sources regarding magnetic hyperthermia, the developing approach to treat otherwise intractable malignancies. </p><p>.

Structurally Well-Defined Au@Cu2- x S Core-Shell Nanocrystals for Improved Cancer Treatment Based on Enhanced Photothermal Efficiency.

Au@Cu2- x S core-shell nanocrystals (NCs) have been synthesized under large lattice mismatch with high crystallinity, controllable shape, and nonstoichiometric composition. Both experimental observations and simulations are used to verify the flexible dual-mode plasmon coupling. The enhanced photothermal effect is harnessed for diverse HeLa cancer cell ablation applications in the NIR-I window (750-900 nm) and the NIR-II window (1000-1400 nm).

Efficient Terahertz detection in black-phosphorus nano-transistors with selective and controllable plasma-wave, bolometric and thermoelectric response.

The ability to convert light into an electrical signal with high efficiencies and controllable dynamics, is a major need in photonics and optoelectronics. In the Terahertz (THz) frequency range, with its exceptional application possibilities in high data rate wireless communications, security, night-vision, biomedical or video-imaging and gas sensing, detection technologies providing efficiency and sensitivity performances that can be "engineered" from scratch, remain elusive. Here, by exploiting the inherent electrical and thermal in-plane anisotropy of a flexible thin flake of black-phosphorus (BP), we devise plasma-wave, thermoelectric and bolometric nano-detectors with a selective, switchable and controllable operating mechanism. All devices operates at room-temperature and are integrated on-chip with planar nanoantennas, which provide remarkable efficiencies through light-harvesting in the strongly sub-wavelength device channel. The achieved selective detection (∼5-8 V/W responsivity) and sensitivity performances (signal-to-noise ratio of 500), are here exploited to demonstrate the first concrete application of a phosphorus-based active THz device, for pharmaceutical and quality control imaging of macroscopic samples, in real-time and in a realistic setting.

Comparative effect of gold nanorods and nanocages for prostate tumor hyperthermia.

Gold nanoparticles have been investigated as photothermal agents, drug delivery carriers, diagnostics, and theranostics. As long-term accumulation of nanoparticles in nontarget tissues is a growing concern, it is vital to establish biodistribution profiles, tumor uptake, and tissue residence times for each nano-based system. This study aimed to investigate the prostate tumor uptake, photothermal therapy mediated macromolecular delivery, acute and chronic biodistribution profiles, and organ residence time differences between two nanoparticles, i.e., gold nanocages and gold nanorods. These particles have tunable surface plasmon resonances in the near infrared, but dissimilar shapes. Gold nanocages and nanorods had very different light to heat transduction efficiencies, with gold nanocages requiring 18.4 times fewer particles and approximately half the gold mass of gold nanorods to achieve the same heating profile given a constant laser intensity. It was also observed that while the photothermal macromolecular delivery enhancements were similar for the two systems when dosed by optical density, the tumoral uptake and biodistribution profiles for each of these shapes differed, with the nanocages residing in the liver, kidneys and spleen for less time than the nanorods. Additionally, it was observed that the nanocages were excreted from the body at a higher percentage of injected dose than the nanorods at both the 7 and 28 day time points. These findings have implications for the use of these constructs in diagnostic and therapeutic applications.

Silicon nanostructures for cancer diagnosis and therapy.

The emergence of nanotechnology suggests new and exciting opportunities for early diagnosis and therapy of cancer. During the recent years, silicon-based nanomaterials featuring unique properties have received great attention, showing high promise for myriad biological and biomedical applications. In this review, we will particularly summarize latest representative achievements on the development of silicon nanostructures as a powerful platform for cancer early diagnosis and therapy. First, we introduce the silicon nanomaterial-based biosensors for detecting cancer markers (e.g., proteins, tumor-suppressor genes and telomerase activity, among others) with high sensitivity and selectivity under molecular level. Then, we summarize in vitro and in vivo applications of silicon nanostructures as efficient nanoagents for cancer therapy. Finally, we discuss the future perspective of silicon nanostructures for cancer diagnosis and therapy.

New perspectives of nanoneuroprotection, nanoneuropharmacology and nanoneurotoxicity: modulatory role of amino acid neurotransmitters, stress, trauma, and co-morbidity factors in nanomedicine.

Recent advancement in nanomedicine suggests that nanodrug delivery using nanoformulation of drugs or use of nanoparticles for neurodiagnostic and/or neurotherapeutic purposes results in superior effects than the conventional drugs or parent compounds. This indicates a bright future for nanomedicine in treating neurological diseases in clinics. However, the effects of nanoparticles per se in inducing neurotoxicology by altering amino acid neurotransmitters, if any, are still being largely ignored. The main aim of nanomedicine is to enhance the drug availability within the central nervous system (CNS) for greater therapeutic successes. However, once the drug together with nanoparticles enters into the CNS compartments, the fate of nanomaterial within the brain microenvironment is largely remained unknown. Thus, to achieve greater success in nanomedicine, our knowledge in understanding nanoneurotoxicology in detail is utmost important. In addition, how co-morbidity factors associated with neurological disease, e.g., stress, trauma, hypertension or diabetes, may influence the neurotherapeutic potentials of nanomedicine are also necessary to explore the details. Recent research in our laboratory demonstrated that engineered nanoparticles from metals or titanium nanowires used for nanodrug delivery in laboratory animals markedly influenced the CNS functions and alter amino acid neurotransmitters in healthy animals. These adverse reactions of nanoparticles within the CNS are further aggravated in animals with different co-morbidity factors viz., stress, diabetes, trauma or hypertension. This effect, however, depends on the composition and dose of the nanomaterials used. On the other hand, nanodrug delivery by TiO2 nanowires enhanced the neurotherapeutic potential of the parent compounds in CNS injuries in healthy animals and do not alter amino acids balance. However, in animals with any of the above co-morbidity factors, high dose of nanodrug delivery is needed to achieve some neuroprotection. Taken together, it appears that while exploring new nanodrug formulations for neurotherapeutic purposes, co-morbidly factors and composition of nanoparticlesrequire more attention. Furthermore, neurotoxicity caused by nanoparticles per se following nanodrug delivery may be examined in greater detail with special regards to changes in amino acid balance in the CNS.

Optical spins and nano-antenna array for magnetic therapy.

Magnetic therapy is an alternative medicine practice involving the use of magnetic fields subjected to certain parts of the body and stimulates healing from a range of health problems. In this paper, an embedded nano-antenna system using the optical spins generated from a particular configuration of microrings (PANDA) is proposed. The orthogonal solitons pairs corresponding to the left-hand and right-hand optical solitons (photons) produced from dark-bright soliton conversion can be simultaneously detected within the system at the output ports. Two possible spin states which are assigned as angular momentum of either +h or -h will be absorbed by an object whenever this set of orthogonal solitons is imparted to the object. Magnetic moments could indeed arise from the intrinsic property of spins. By controlling some important parameters of the system such as soliton input power, coupling coefficients and sizes of rings, output signals from microring resonator system can be tuned and optimized to be used as magnetic therapy array.

Nanotechnology in plastic surgery.

BACKGROUND: Nanotechnology has made inroads over time within surgery and medicine. Translational medical devices and therapies based on nanotechnology are being developed and put into practice. In plastic surgery, it is anticipated that this new technology may be instrumental in the future. Microelectromechanical systems are one form of nanotechnology that offers the ability to develop miniaturized implants for use in the treatment of numerous clinical conditions. The authors summarize their published preliminary findings regarding a microelectromechanical systems-based electrochemical stimulation method through modulation of ions around the nerve that is potentially implantable and clinically efficacious, and expand upon current and potential usages of nanotechnology in plastic surgery. METHODS: Sciatic nerves (n = 100) of 50 American bullfrogs were placed on a microfabricated planar gold electrode array and stimulated electrically. Using Ca(2+)-selective membranes, ion concentrations were modulated around the nerve environment in situ. In addition, a comprehensive review of the literature was performed to identify all available data pertaining to the use of nanotechnology in medicine. RESULTS: A 40 percent reduction of the electrical threshold value was observed using the Ca(2+) ion-selective membrane. The uses of nanotechnology specifically applicable to plastic surgery are detailed. CONCLUSIONS: Nanotechnology may likely lead to advancements in the art and science of plastic surgery. Using microelectromechanical systems nanotechnology, the authors have demonstrated a novel means of modulating the activation of nerve impulses. These findings have potentially significant implications for the design of special nano-enhanced materials that can be used to promote healing, control infection, restore function, and aid nerve regeneration and rehabilitation.

Magnetic resonance propulsion, control and tracking at 24 Hz of an untethered device in the carotid artery of a living animal: an important step in the development of medical micro- and nanorobots.

Our recent demonstration of a ferromagnetic bead being navigated automatically inside the carotid artery of a living animal at an average speed of 10 cm/s using a clinical MRI system may be considered as a significant step in the field of medical micro- and nanorobotics. This is particularly true when we consider that an appropriate tracking method was embedded in the closed-loop control process allowing the blood vessels to be considered as navigational routes, providing maximum access for conducting operations inside the human body. But more importantly, this demonstration not only validates preliminary theoretical models but provides us with initial insights about the strategies and approaches that are likely to be used to navigate under computer control, micro- and nanodevices including nanorobots from the largest to the smallest diameter blood vessels that could be used to reach targets inside the human body. Here, based on these initial experimental data obtained in vivo, such strategies and methods are briefly described with some initial design concepts of medical interventional micro- and nanorobots.