Silver has long been recognized for its infection-fighting properties and it has a long and intriguing history as an antibiotic in human health care. In ancient Greece and Rome, silver was used to fight infections and control spoilage. In the late 19th century, the botanist von Naegeli discovered that minute concentrations of silver contained microbiocidal properties. However, as the first antibiotics were discovered, this old household remedy was quickly forgotten. In an alarming trend, bacteria and other microorganisms that cause infections are becoming remarkably resilient and can develop ways to survive drugs meant to kill or weaken them. This antibiotic resistance is due largely to the increasing use of antibiotics. This led researchers to re-evaluate old antimicrobial substances such as silver. Silver nanoparticles have become the promising antimicrobial material in a variety of applications because they can damage bacterial cells by destroying the enzymes that transport cell nutrient and weakening the cell membrane or cell wall and cytoplasm. Unfortunately, in practical applications, the pure silver nanoparticles are unstable with respect to agglomeration. In most cases, this aggregation leads to the loss of the properties associated with the nanoscale of metallic particles. The stabilization of metallic colloids and thus the means to preserve their finely dispersed state is a crucial aspect to consider during their applications. Researchers in China have successfully demonstrated the use of a natural macroporous matrix for fabricating a stable, biocompatible nanocomposite with high silver content for antimicrobial purposes.
Nanosurgery holds the promise of studying or manipulating and repairing individual cells without damaging the cell. For instance, nanosurgery could remove or replace certain sections of a damaged gene inside a chromosome; sever axons to study the growth of nerve cells; or destroying an individual cell without affecting the neighboring cells. While the cell nucleus has been transplanted between cells during cloning using micropipette technologies, these methods are too crude for other subcellular structures. First steps towards nanosurgery have been made using so-called 'optical tweezers', where the energy of laser light is used to trap and manipulate nanoscale objects, for instance the nucleus of a cell, without mechanical contact. Combined with a laser scalpel (use of lasers for cutting and ablating biological objects) optical tweezers have been used to study cell fusion, DNA-cutting, etc. Unfortunately, while optical tweezers offer exquisite sensitivity in their ability to position micro- and nanoparticles, they suffer from one important disadvantage: the trapped particle is localized at the laser focus where light intensity is the highest. As a result, the laser light used to trap a particle also has a propensity to photobleach and photodamage the particle, especially when the particle is fragile and small (e.g., a subcellular organelle that is fluorescently labeled). Minimizing this drawback, new research describes the use of polarization-shaped optical vortex traps for the manipulation of particles and subcellular structures.
As the most common endocrine metabolic disorder for human beings, diabetes mellitus with an obvious phenomenon of high blood glucose concentrations results from a lack of insulin. Despite the availability of treatment, diabetes has remained a major cause of death and serious vascular and neuropathy diseases. Continuously monitoring the blood glucose level and intermittent injections of insulin are widely used for effective control and management of diabetes. Extensive research has been conducted to develop optimal glucose sensors for diagnostic purposes. Currently, the commercially available glucose biosensors still have some problems to overcome, such as time consuming, relatively low sensitivity, bad reliability. The performance of a glucose sensor is largely dependent upon the materials which construct the sensor. Recent research effort for glucose sensing have turned to on nanomaterials. Nanomaterial-based biosensors already have shown the capability of detecting trace amounts of biomolecules in real time. New research has studied the electrochemical characteristics of platinum decorated carbon nanotubes (CNTs) as a promising candidate for glucose sensing. Its improved performance may encourage further exploration of this novel nanomaterial in the field of bioapplications.
Thermolysis (from thermo- meaning heat and -lysis meaning break down) is a chemical process by which a substance is decomposed into other substances by use of heat. In photothermolysis the transfer of laser energy is used to generate the required heat. And finally, nanophotothermolysis is the process where nanoparticles, when irradiated by short laser pulses, get hot so quickly that they explode. This thermal explosion of nanoparticles (nanobombs) may be accompanied by optical plasma, generation of shock waves with supersonic expansion and particle fragmentation with fragments of high kinetic energy, all of which can contribute to the killing of cancer cells they are attached to. By engineering the laser wavelength, pulse duration and particle size and shape, this technology can provide highly localized damage in a controlled manner, potentially varying from a few nanometers (for DNA) to tens of microns (the size of a single cancer cell) without damaging the surrounding tissue.
If you had brain tumor, would you rather receive your medicine through an injection in the arm or have a hole drilled in your skull? Even if you opted for the 'hole-in-the-skull' method, brain cancers are often inoperable due to their location within critical brain regions or because they are too small to detect. Nanotechnology offers a vision for a 'smart' drug approach to fighting tumors: the ability of nanoparticles to locate cancer cells and destroy them with single-cell precision. One of the most important applications for such nanoparticulate drug delivery could be the delivery of the drug payload into the brain. However, crossing the brains protective shield, the blood-brain barrier, is a considerable challenge. Novel targeted nanoparticulate drug delivery systems that are able to cross this barrier bring us closer to this vision of brain cancer destroying drugs.
Drug intoxication, developed as a result of accidental overdosing, is a serious health problem. Drug overdoses are sometimes also caused intentionally to commit suicide, but many drug overdoses are usually the result of either irresponsible behavior, or the misreading of product labels. Other causes of overdose (especially heroin) include multiple drug use with counter indications (cocaine/amphetamines/alcohol) or use after a period of abstinence. According to the National Center for Health Statistics, in the U.S. alone almost 20,000 people a year die due to drug overdoses and accidental poisoning. While there has been a tremendous effort to develop drug delivery methods using nanotechnology, a new report shows that this could work the other way around as well, and that porous nanoparticles can soak up drug molecules in the body like a sponge. This could help to reduce fatalities from overdoses, according to tests showing that tiny spheres of poly(acrylic acid) can absorb substantial amounts of an antidepressant and an anesthetic in just a few minutes. In short, nanoparticles can act as potent antidotes!
A novel discipline is emerging in medicine: nanoscopic medicine. Based on the premises that diseases manifest themselves as defects of cellular proteins, these proteins have been recently shown to form specific complexes exerting their functions as if they were nanoscopic machines. Nanoscopic medicine refers to the direct visualization, analysis (diagnosis) and modification (therapy) of nanoscopic protein machines in life cells and tissues with the aim to improve human health. The term nanoscopic medicine was coined by a group of researchers in Germany whose mission is to extend live cell nanoscopy into a comprehensive diagnostic and therapeutic scheme. This includes both the creation of a set of novel instruments and the analysis of nanoscopic protein machine networks in health and disease. In addition, they seek to construct artificial devices mimicking cellular nanomachines.
There has been a great deal of interest in the toxicity of nanoparticles in the context of respiratory health. The responses of cells exposed to nanoparticles have been studied with regard to toxicity, but very little attention has been paid to the possibility that some types of particles can protect cells from various forms of lethal stress. Research has shown that nanoparticles composed of cerium oxide or yttrium oxide protect nerve cells from oxidative stress and that the neuroprotection is independent of particle size. This has led researchers to the conclusion that there is a potential for engineering this group of nanoparticles for therapeutic purposes.