Silver nanoparticles as a new generation of antimicrobials.

This review is written with the goal of informing public health concerns related to nanoscience, while raising awareness of nanomaterials toxicity among scientists and manufacturers handling them. We show that humans have always been exposed to nanoparticles and dust from natural sources and human activities, the recent development of industry and combustion-based engine transportation profoundly increasing anthropogenic nanoparticulate pollution. The key to understanding the toxicity of nanoparticles is that their minute size, smaller than cells and cellular organelles, allows them to penetrate these basic biological structures, disrupting their normal function. Among diseases associated with nanoparticles are asthma, bronchitis, lung cancer, neurodegenerative diseases (such as Parkinson`s and Alzheimer`s diseases), Crohn`s disease, colon cancer. Nanoparticles that enter the circulatory system are related to occurrence of arteriosclerosis, and blood clots, arrhythmia, heart diseases, and ultimately cardiac death. We show that possible adverse effects of nanoparticles on human health depend on individual factors such as genetics and existing disease, as well as exposure, and nanoparticle chemistry, size, shape, and agglomeration state. The faster we will understand their causes and mechanisms, the more likely we are to find cures for diseases associated with nanoparticle exposure. We foresee a future with better-informed, and hopefully more cautious manipulation of engineered nanomaterials, as well as the development of laws and policies for safely managing all aspects of nanomaterial manufacturing, industrial and commercial use, and recycling.

Nanomaterials and nanoparticles: Sources and toxicity

This review is presented as a common foundation for scientists interested in nanoparticles, their origin, activity, and biological toxicity. It is written with the goal of rationalizing and informing public health concerns related to this sometimes-strange new science of “nano,” while raising awareness of nanomaterials’ toxicity among scientists and manufacturers handling them. We show that humans have always been exposed to tiny particles via dust storms, volcanic ash, and other natural processes, and that our bodily systems are well adapted to protect us from these potentially harmful intruders. The reticuloendothelial system, in particular, actively neutralizes and eliminates foreign matter in the body, including viruses and nonbiological particles. Particles originating from human activities have existed for millennia, e.g., smoke from combustion and lint from garments, but the recent development of industry and combustion-based engine transportation has profoundly increased anthropogenic particulate pollution. Significantly, technological advancement has also changed the character of particulate pollution, increasing the proportion of nanometer-sized particles-“nanoparticles”-and expanding the variety of chemical compositions. Recent epidemiological studies have shown a strong correlation between particulate air pollution levels, respiratory and cardiovascular diseases, various cancers, and mortality. Adverse effects of nanoparticles on human health depend on individual factors such as genetics and existing disease, as well as exposure, and nanoparticle chemistry, size, shape, agglomeration state, and electromagnetic properties. Animal and human studies show that inhaled nanoparticles are less efficiently removed than larger particles by the macrophage clearance mechanisms in the lungs, causing lung damage, and that nanoparticles can translocate through the circulatory, lymphatic, and nervous systems to many tissues and organs, including the brain. The key to understanding the toxicity of nanoparticles is that their minute size, smaller than cells and cellular organelles, allows them to penetrate these basic biological structures, disrupting their normal function. Examples of toxic effects include tissue inflammation, and altered cellular redox balance toward oxidation, causing abnormal function or cell death. The manipulation of matter at the scale of atoms, “nanotechnology,” is creating many new materials with characteristics not always easily predicted from current knowledge. Within the nearly limitless diversity of these materials, some happen to be toxic to biological systems, others are relatively benign, while others confer health benefits. Some of these materials have desirable characteristics for industrial applications, as nanostructured materials often exhibit beneficial properties, from UV absorbance in sunscreen to oil-less lubrication of motors. A rational science-based approach is needed to minimize harm caused by these materials, while supporting continued study and appropriate industrial development. As current knowledge of the toxicology of “bulk” materials may not suffice in reliably predicting toxic forms of nanoparticles, ongoing and expanded study of “nanotoxicity” will be necessary. For nanotechnologies with clearly associated health risks, intelligent design of materials and devices is needed to derive the benefits of these new technologies while limiting adverse health impacts. Human exposure to toxic nanoparticles can be reduced through identifying creation-exposure pathways of toxins, a study that may someday soon unravel the mysteries of diseases such as Parkinson’s and Alzheimer’s. Reduction in fossil fuel combustion would have a large impact on global human exposure to nanoparticles, as would limiting deforestation and desertification. While nanotoxicity is a relatively new concept to science, this review reveals the result of life’s long history of evolution in the presence of nanoparticles, and how the human body, in particular, has adapted to defend itself against nanoparticulate intruders.

https://avs.scitation.org/doi/pdf/10.1116/1.2815690

https://cmapspublic3.ihmc.us/rid=1266358861321_2027852911_13457/Wound%20Healing%20Dressings%20and%20Drug%20Delivery%20Systems.pdf

Wound healing dressings and drug delivery systems: a review.

Burns are one of the most common and devastating forms of trauma. Patients with serious thermal injury require immediate specialized care in order to minimize morbidity and mortality. Significant thermal injuries induce a state of immunosuppression that predisposes burn patients to infectious complications. A current summary of the classifications of burn wound infections, including their diagnosis, treatment, and prevention, is given. Early excision of the eschar has substantially decreased the incidence of invasive burn wound infection and secondary sepsis, but most deaths in severely burn-injured patients are still due to burn wound sepsis or complications due to inhalation injury. Burn patients are also at risk for developing sepsis secondary to pneumonia, catheter-related infections, and suppurative thrombophlebitis. The introduction of silver-impregnated devices (e.g., central lines and Foley urinary catheters) may reduce the incidence of nosocomial infections due to prolonged placement of these devices. Improved outcomes for severely burned patients have been attributed to medical advances in fluid resuscitation, nutritional support, pulmonary and burn wound care, and infection control practices.

Burn Wound Infections

Burn wound healing and skin substitutes.

https://www.cidjournal.com/article/S0738-081X(04)00141-5/pdf

The role of skin substitutes in the treatment of burn injuries.

EBA in evidence.

Background: Topical negative-pressure therapy is a widely used wound management system that generates a negative pressure at the wound surface through a foam pad, which aids in wound stimulation through mechanical forces on the wound bed. System guidelines state that the foam dressing should be placed in direct apposition with the wound surface; however, an interface dressing is often inserted at this point to promote comfort at dressing changes. Methods: Topical negative-pressure dressings were applied tb 40 healthy volunteers. Pressures at the skin surface under the dressing were recorded and compared with those measured by a topical negative-pressure machine using the Therapeutic Regulated Accurate Care pad system. These were repeated, inserting different types of interface dressings: petroleum jelly (Vaseline)-impregnated gauze, nonadherent silicone dressing, and mylar polyester film dressing. Results: Pressures recorded at the skin interface with no interface dressing were dose to those set on the topical negative-pressure machine (mean pressure change, -5.11 ± 0.55 mmHg). Interposition of dressings at the skin/ foam interface affected pressure transmission through the foam, and some caused significant decreases in pressures recorded at the skin surface (e.g., Vaseline-impregnated gauze: mean pressure change, -11.76 mmHg; maximum pressure change, -41 mmHg). Conclusion: The loss in negative pressure means that pressures designated by the machine cannot be relied on as a measure of wound pressure when certain dressings are used at the interface. This could be important in determining the outcome of some wounds under topical negative-pressure therapy treatment.

Interface dressings influence the delivery of topical negative-pressure therapy.

Better care for patients and improved health care depends on the availability of good information which is accessible when and where it is needed. The development of technology, more specifically the Internet, has expanded the means whereby information can be acquired and transmitted over large distances enabling the concept of telemedicine to become a reality. Telemedicine, defined as the practise of medicine at a distance, encompasses diagnosis, education and treatment. It is a technology that many thought would expand rapidly and change the face of medicine. However, this has not happened and during the last decade although certain telemedicine applications, such as video-consulting and teleradiology, have matured to become essential health care services in some countries, others, such as telepathology, remain the subject of intensive research effort. Telemedicine can be used in almost any medical specialty although the specialties best suited are those with a high visual component. Wound healing and wound management is thus a prime candidate for telemedicine. Development of a suitable telemedical system in this field could have a significant effect on wound care in the community, tertiary referral patterns and hospital admission rates.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1742-4801.2004.00055.x

P. G. Shakespeare

Papers

Burn wound healing and skin substitutes.

The role of skin substitutes in the treatment of burn injuries.

EBA in evidence.

Interface dressings influence the delivery of topical negative-pressure therapy.

Telemedicine in wound healing