Frontiers in Clinical Drug Research - Anti Infectives: Volume 6

Atta-ur-Rahman

• Editore: Bentham Science Publishers
• Anno: 2020
• ISBN:
  9789811425745
• Argomento: Physical Sciences
• Categoria: Clinical Chemistry

Frontiers in Clinical Drug Research – Anti infectives is a book series that brings updated reviews to readers interested in learning about advances in the development of pharmaceutical agents for the treatment of infectious diseases. The scope of the book series covers a range of topics including the chemistry, pharmacology, molecular biology and biochemistry of natural and synthetic drugs employed in the treatment of infectious diseases. Reviews in this series also include research on multi drug resistance and pre-clinical / clinical findings on novel antibiotics, vaccines, antifungal agents and antitubercular agents. Frontiers in Clinical Drug Research – Anti infectives is a valuable resource for pharmaceutical scientists and postgraduate students seeking updated and critically important information for developing clinical trials and devising research plans in the field of anti infective drug discovery and epidemiology. The sixth volume of this series features these interesting reviews: - Direct-acting antiviral drugs for treatment of Hepatitis C virus infection - Plant lattices as anti-infective compounds - Antimicrobial materials and devices for biomedical applications - Recent advances in the treatment of toxoplasmosis - Antimicrobial immunoglobulin prophylaxis and therapy - Targeting Magnesium Homeostasis as Potential Anti-Infective Strategy Against Mycobacteria

Antimicrobial Materials and Devices for Biomedical Applications

Felipe López-Saucedo¹, Guadalupe G. Flores-Rojas^{1, *}, Justine P. R. O. Varca², Gustavo H.C. Varca², Emilio Bucio^{1, *}

¹ Departamento de Química de Radiaciones y Radioquímica, Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, Mexico City04510, Mexico

² Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP, São Paulo, Brazil

Abstract

Bioaccumulation in sanitary devices, caused by opportunistic pathogens, intervenes negatively in the recovery of a patient since these are able to provoke a mild or life-threatening infection. Thus, surfaces of certain materials such as gauzes, catheters, sutures, etc., which are adjacent or directly exposed to a healing zone, are prone to become sites for the growth, proliferation, and spread of pathogenic microorganisms. Although in surgical or healing processes, sterile materials are usually applied, the time of contact with biological interfaces is long enough to make the sterilization but not enough to control and prevent an infection since pathogens abound in the surroundings. Air, water, and soil can be potential vectors, without considering those factors related to iatrogenesis that also play a role in the opportunities for the patient's recovery. Within this context, engineered materials are currently being developed and explored towards devices and biomaterials with improved design, performance, duration, biocompatibility aiming to be safer for the user. The surface functionalization of materials with antimicrobial agents is a highlighted alternative to overcome this issue. This chapter addresses current antimicrobial materials, as well as strategies for obtaining antimicrobial surfaces and coating as well as their properties. In addition, the safety assessment of biomedical applications and international standards are discussed.

Keywords: Antimicrobial agents, Antimicrobial surfaces, Advanced materials, Biomedical devices, Biological evaluation, Bioactive molecules, Coatings, International standards, Safety assessment, Surface functionalization.

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^* Corresponding authors Guadalupe G. Flores-Rojas and Emilio Bucio: Departamento de Química de Radiaciones y Radioquímica, Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, Mexico City 04510, Mexico; E-mails: [email protected]; [email protected]

OVERVIEW OF ANTIMICROBIAL MATERIALS AND SURFACES

Since ancient times, the history of humanity reveals a constant struggle to fight bacteria and other pathogenic microorganisms. Infections are responsible for a vast number of deaths around the world, and before the outbreak of antibiotics discovery, for instance, several materials with anti-microbial properties were applied. Therefore, an adequate anti-infective strategy is crucial in hospitals and demands great efforts against the outbreaks of infections, which are triggered by a wide variety of microorganisms.

Some of the most common pathogens infections are caused by Pseudomonas aeruginosa, Staphylococcus aureus, Candida albicans, Candida aspergillus, etc., which are responsible for several illnesses that tend to be developed from mild to life-threatening if undesirable proliferation takes place in the human body. These include skin and wound infections, eczema, abscesses, endocarditis (biocontamination of heart valves), pneumonia, onychomycosis, candidiasis or thrush (both vaginal and oral), aspergillosis, etc.

Nevertheless, the pathogens are not restricted to the colonization of surfaces but also they invade interstitial extracellular cavities, and are capable of internalizing in the cells of the connective tissue [1, 2]. Thus, the pathogens can survive to chemotherapy treatments, because these are well protected by the intracellular reservoir, ready to start the infection again, once antimicrobial concentrations have lost their efficacy.

Consequently, the use of antibiotics able to reach intracellularly hidden bacteria is crucial. One of the challenges is that the antibiotics penetrate the membranes of eukaryotic cells, since antibiotics as gentamicin are incapable of reaching the intracellular compartment, and even the gentamicin-laden biomaterials, occasionally turn into ineffective or even a counterproductive option in cases where strains capable of cell internalization are involved in the infection, such as S. aureus, which is a typical pathogen [3].

In principle, the use of microbial agents would be a perfect fit if bacterial resistance, among other problems, would not arise from the use, misuse or overuse of antimicrobial agents. Within this context, technological advancements have been directed to control pathogenic growth or population on surfaces, for example, as fighting infections locally seems a lot more effective and rationale than fighting it at a systemic level, as it would require fewer amounts of antibacterial agents and control the infection on site.

The concept of controlling and designing antibacterial surfaces has a direct and deep impact on reducing healthcare-associated infections and mortality. Overall, this promising technology holds a relevant contribution economically, industrially and from a healthcare perspective. In addition, such materials, also named self-cleaning devices, compose a more sustainable system as depending on the technology applied, none or almost no antimicrobials are released to the ecosystem, thus also being entitled as environmentally friendly.

The topic is, focused on the ability to control the pathogenic population in distinct environments, specially, bound to catheter materials or devices, when in direct or indirect contact with the body over time. At first glance, sterilization of medical devices assures acceptable levels of decontamination concerning biomedical applicators. However, it is limited and variably effective in controlling the pathogenic microorganisms that will persist grow, and induce biofilm formation on the material or devices over time.

In such conditions, strategies to control bioburden abound and not limited to selective killing towards a specific pathogen, or using antimicrobial or static agents is paramount. This measure in addition, is driven towards controlling or modifying surfaces to block or modulate bacterial adhesion or growth.

METHODS TO ACHIEVE ANTIMICROBIAL SURFACES

One way to classify antimicrobial materials is based on physical, chemical, and biological synthesis methods. In this section, the chemical methods are referred to those, which are compounds involved in the interaction via covalent bonds, to immobilize or functionalize materials, regardl...