Papers by Keyword: Nanomedicine

Abstract: Biomimetic nanocrystalline apatites are analogous to bone mineral. They can be exploited not only for bone regeneration applications, but it is also possible to take advantage of their biomimetic features to explore novel domains of research such as in nanomedicine, if the nanoparticles are stabilized as a colloidal formulation. In this contribution, we concentrate on AEP/HMP-stabilized colloidal apatite nanoparticles (NPs) and on their interaction with different types of cells so as to get experimental evidence on their low cytotoxicity, non-proinflammatory potential, and good compatibility with Red Blood Cells. We then started to explore their interaction with an artificial free-standing phospholipid bilayer, as a simplified model for cell membranes: results indicate, for the first time, that these colloidal apatite NPs can modulate phospholipid bilayer membrane properties, and may even favor the permeation of small molecules (illustrated here with luminescent FITC), which could ultimately be exploited for nanomedicine applications in view of enhancing intracellular drug delivery.

Abstract: Porous silicon (PSi) with a suite of most desirable biomaterial properties has attracted great attention as a multifunctional nanoplatform for bioimaging and drug delivery. Various surface functionalization treatments have been reported for PSi to use as an active tumor cell targeting nanovector. In this study, we investigated surface functionalization treatments using a peptide that is specific to the emerging biomarker legumain. The PSi nanoparticles were coated with dextran and subsequently two types of legumain targeting peptide, Y-shaped and linear chain, were conjugated to produce the functionalized PSi. The functionalized (ligand-conjugated) PSi materials were characterized for morphology, size, functional groups, and fluorescence response using electron and fluorescence microscopy and vibrational spectroscopy techniques. Fluorescence microscopy imaging with two excitation wavelengths (450 nm and 600 nm) suggests comparable fluorescence response of the conjugated PSi to “bare” PSi and the suitability of the PSi functionalized with peptide for bioimaging.

Abstract: Recently, numerous delafossite oxides in nanoscale have been reported for diverse applications. The present review summarized the recent overall views of delafossite nanoparticles in diverse applications such as energy, catalysis, photocatalysis, nanomedicine, sensors, electrochemical devices and environmental concerns. Delafossite nanoparticles possess unique features such as different and wide chemical composition, large surface area, small energy gap, ability for further functionalization, possess dual-active sites with different oxidation states (A⁺ and M³⁺), and eager for doping with various species with feasibility to undergo structure modification. Thus, they provided promising application such as solar cell, photocatalysis, hydrogen production, bioactive materials, separation purposes and others. Pros, cons, current and future status were also reviewed.

Abstract: As the development of nanotechnology has extended to the world of biomolecules, a revolution has occurred in the design and assembly of nanomaterials for drug delivery with a significant potential to impact drug efficacy and patient outcomes. Currently a number of nanomaterials are under investigation for their suitability as sustained, controlled and targeted drug carriers. Leading edge of the rapidly developing nanosciences is the development and assessment of these nanomaterials, with specific physicochemical properties different from their larger/ bulk counterparts, as vehicles for transport of small and large drug molecules. The characteristics such as size, shape, chemical composition, surface structure and charge, aggregation and agglomeration, and solubility, can greatly influence interactions of these nanostructured systems or carriers with biomembranes and cells. The selectivity and reactivity achieved due to the very small size assigns these systems with a wide spectrum of applications. In this review, nanomaterials are considered in terms of the physical attributes or pharmaceutical effects allocated by them to the all-inclusive carrier or vehicle system (s). However we will limit our discussion to lipidic and polymeric nanomaterials, the two most commonly promoted, and safe nanosystems for delivery of both, the chemical or small molecular entities (SME) and the macromolecules including genes and siRNA.Contents of Paper

Abstract: This work was instigated by the fact that sol-gel chemistry provides a relatively simple way to incorporate recognition species in a stable host green environment. In this new strategy, which represents a low cost example of bottom-up nanoassembly, chemistry art is entering the field of nanobiotechnology in fabrication and control of an expanded homogeneous length of separate single-walled and ordered, helical lattice-like open-ended natural protein nanotubes (PNTs) and also creative novel bio-nanohybrids. A new type of protein nanohybrids containg nanotubes-nanorods, nanotubes-nanofibers, nanotubes core-shell nanofibers were prepared using an electrostatic self-assembly method with the aid of chemical partial hydrolysis of milk protein α-lactalbumin (sol-gel technique) at a suitable pH value for the first time. They can have long helically coiled length and are promising for high capacity drug loading and applying in nanomedicine as organ transplantation in human body and implant material, because of their improved stability and unique mechanical and lattice thermal resistivity properties. In this study, various valuable ligand or binding sites such as distinct Mn⁺², Ca⁺²or Zn⁺² cations were used for incorporated into protein nanostructures as the self-assembly essential stimulant motor. It was found that the designed nanobioproducts could retain and stabilize as very clear and transparent green aqueous nanobiofluids during two years.

Abstract: The use of metal chelators is becoming increasingly important in the development of new tracers for molecular imaging. With the rise of the field of nanotechnology, the fusion of both technologies has shown great potential for clinical applications. The pharmacokinetcs of nanoparticles can be monitored via positron emission tomography (PET) after surface modification and radiolabeling with positron emitting radionuclides. Different metal ion chelators can be used to facilitate labeling of the radionuclides and as a prerequisite, optimized radiolabeling procedure is necessary to prevent nanoparticle aggregation and degradation. However, the effects of chelator modification on nanoparticle pharmacokinetic properties have not been well studied and currently no studies to date have compared the biological effects of the use of different chelators in the surface modification of nanoparticles.

Abstract: This paper reports on two examples of biomedical applications of ceramic nanoparticles. Thanks to their physical and chemical inertia, barium titanate nanoparticles and boron nitride nanotubes have been proved to have an optimal in vitro biocompatibility, even at high concentrations. Barium titanate nanoparticles-doxorubicin composites are successfully internalized by cancer cells, and allow for a considerable enhancement of drug up-take. Conversely, boron nitride nanotubes are explored as “nanotransducers”, thanks to their excellent piezoelectric properties. These two examples encourage further investigations and applications in biology and medicine of ceramic nanomaterials, that exhibit interesting advantages respect to traditional materials.

Abstract: Each year 10.9 million people worldwide are diagnosed with cancer and it is the third most common disease in world. Early diagnosis of cancer and cure are major challenges. Recent advances in development of novel biomaterials as well as rapid progress in the area of nano-biotechnology has potentials to change all the current modalities of cancer diagnosis and management. The unique physical and chemical properties of nanomaterials are extremely helpful for detection of biomarkers of the disease, molecular imaging as well as specific targeted therapy sparing the normal organs. Nanoparticle (NP) has large surface area which can be conjugated or coated with different molecular probes for diverse detection system (optical, electrical, magnetic etc.) as well as used as a vehicle to carry different biomolecules and anticancer drugs to tumor cells. Semiconductor quantum dot (QD) with novel optical and electronic properties helped to devise a new class of NP probes for molecular, cellular, and in vivo imaging. A large variety of materials ranging from metal, ceramic, polymer, lipid, protein and nucleic acid are used for developing novel nanoparticles with multiple functions which can detect different aspects of cancer biology and progression. The major issue of concern is biocompatibility and safety of these materials and their fate after in-vivo use. However with collaborative interdisciplinary research it will be possible to develop safer nanomaterials in future

Abstract: Many recently designed drug delivery systems have been constructed from nano-sized components that serve as the carrier or targeting ligand for a therapeutic agent. Even though these materials have been regarded previously as inert or non-active components of dosage forms, they are now recognized as sometimes being even more important than the drug itself. Hence, it is becoming increasingly imperative that the pharmaceutically relevant properties, including identity, physicochemical characteristics, purity, solubility and toxicity, of these functional nano-excipients be fully characterized. Carbon nanotubes (CNTs) are novel nanomaterials made of carbon atoms that have wide application potential in many areas of nanomedicine. However, because of their significant potential, CNTs, as building blocks for nanomedicines, need to be characterized more fully. Studies to date indicate that both physical and chemical properties of CNTs play an important role in their interactions with cells. Therefore, a full understanding of the physical properties of CNTs, such as identity, chirality, particle size, aspect ratio, morphology and dispersion state, as well as chemical properties such as purity, defect sites and types and functional groups, will be essential to develop a full characterization panel of these versatile nanomaterials.

Abstract: Current epilepsy rates in Mexico are 4% (SERSAME-Health Ministry), of which 80% correspond to Temporal Lobe Epilepsy (TLE). Antiepileptic drug administration is systemic, meaning that 90% of the active agent is lost between administration and delivery to the epileptic focus in the brain. Severe toxic secondary effects may occur as a result. The present study is aimed at developing an alternative antiepileptic drug delivery system. In this study, a sol-gel nanostructured titania device, in which valproic acid (VPA) has been encapsulated. This is a nanoparticulate device, which is biocompatible with brain tissue. Stereotactic surgery was used to implant the reservoirs in the temporal lobe of Wistar rats, using chemical kindling, which was used to induce epilepsy. The reservoir was designed to release the drug at a constant rate over a period of at least one year. A functional study was performed on the efficiency of drug delivery in order to evaluate the effect on spontaneous and induced neuron electrical activity. A new discovery, which is presented here, shows that in the case of damaged brain tissue, as is the case in epilepsy, the accumulation of red globules, oxygen transportation results in the formation of calcium carbonate crystals which surround the epileptic focus. Because these crystals have a specific polarization, we propose to characterize their influence on the EEG using statistical methods. The electrical activity was measured by electroencephalography using 5 healthy rats without and 5 rats with an implanted VPA/device. Cerebral signals describe the complex behavior of the brain dynamics as a function of time. Fractal algorithms are sensitive to fluctuations and lead to the analysis and characterization of this kind of complex phenomena. A systematic study of these EEG’s was made in order to observe the variation of signals during seizures and on the controlled rate of release of VPA. We have estimated the Hurst exponent (H) to measure long range-dependence. Preliminary results show that for the control group, signal behavior is persistent (H>0.5), while for the epileptic group antipersistency was observed (H<0.5), with variations due seizure stages. During the protection period using VPA, preliminary results show that values tend to reach original behavior, as the crisis is stabilized.