Infectious diseases are the second most important cause of human death worldwide; Staphylococcus aureus (S. aureus) is a very common human pathogenic microorganism that can trigger a variety of infectious diseases, such as skin and soft tissue infections, endocarditis, osteomyelitis, bacteremia, and lethal pneumonia. Moreover, according to the sensitivity to antibiotic drugs, S. aureus can be divided into methicillin-sensitive Staphylococcus aureus (MSSA) and methicillin-resistant Staphylococcus aureus (MRSA). In recent decades, due to the evolution of bacteria and the abuse of antibiotics, the drug resistance of S. aureus has gradually increased, the infection rate of MRSA has increased worldwide, and the clinical anti-infective treatment for MRSA has become more difficult. Accumulating evidence has demonstrated that the resistance mechanisms of S. aureus are very complex, especially for MRSA, which is resistant to many kinds of antibiotics. Therefore, understanding the drug resistance of MRSA in a timely manner and elucidating its drug resistance mechanism at the molecular level are of great significance for the treatment of S. aureus infection. A large number of researchers believe that analyzing the molecular characteristics of S. aureus can help provide a basis for designing effective prevention and treatment measures against hospital infections caused by S. aureus and further monitor the evolution of S. aureus. This paper reviews the research status of MSSA and MRSA, the detailed mechanisms of the intrinsic antibiotic resistance and the acquired antibiotic resistance, the advanced research on anti-MRSA antibiotics and novel therapeutic strategies for MRSA treatment.

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Prevalence and Therapies of Antibiotic-Resistance in Staphylococcus aureus.

MicroRNA delivery through nanoparticles.

Nanoparticles (NPs) have emerged as a powerful drug-delivery tool for cancer therapies to enhance the specificity of drug actions, while reducing the systemic side effects. Nonetheless, NPs interact massively with the surrounding physiological environments including plasma proteins upon administration into the bloodstream. Consequently, they are rapidly cleared from the blood circulation by the mononuclear phagocyte system (MPS) or complement system, resulting in a premature elimination that will cause the drug release at off-target sites. By grafting a stealth coating layer onto the surface of NPs, the blood circulation half-life of nanomaterials can be improved by escaping the recognition and clearance of the immune system. This review focuses on the basic concept underlying the stealth behavior of NPs by polymer coating, whereby the fundamental surface coating characteristics such as molecular weight, surface chain density as well as conformations of polymer chains are of utmost importance for efficient protection of NPs. In addition, the most commonly used stealth polymers such as poly(ethylene glycol) (PEG), poly(2-oxazoline) (POx), and poly(zwitterions) in developing long-circulating NPs for drug delivery are also thoroughly discussed. The biomimetic strategies, including the cell-membrane camouflaging technique and CD47 functionalization for the development of stealth nano-delivery systems, are highlighted in this review as well.

https://www.mdpi.com/2079-4991/10/4/787/pdf

Stealth Coating of Nanoparticles in Drug-Delivery Systems.

The use of nanoparticles (NP) in diagnosis and treatment of many human diseases, including cancer, is of increasing interest. However, cytotoxic effects of NPs on cells and the uptake efficiency significantly limit their use in clinical practice. The physico-chemical properties of NPs including surface composition, superficial charge, size and shape are considered the key factors that affect the biocompatibility and uptake efficiency of these nanoplatforms. Thanks to the possibility of modifying physico-chemical properties of NPs, it is possible to improve their biocompatibility and uptake efficiency through the functionalization of the NP surface. In this review, we summarize some of the most recent studies in which NP surface modification enhances biocompatibility and uptake. Furthermore, the most used techniques used to assess biocompatibility and uptake are also reported.

/pdf/nanoparticle-surface-functionalization-how-to-improve-1mfxwi5jdz.pdf

Nanoparticle Surface Functionalization: How to Improve Biocompatibility and Cellular Internalization.

Protein corona presents a major obstacle to bench-to-bedside translation of targeted drug delivery systems, severely affecting targeting yields and directing unfavorable biodistribution. Corona-mediated targeting provides a new impetus for specific drug delivery by precisely manipulating interaction modes of functional plasma proteins on nano-surface. Here bio-inspired liposomes (SP-sLip) were developed by modifying liposomal surface with a short nontoxic peptide derived from Aβ1-42 that specifically interacts with the lipid-binding domain of exchangeable apolipoproteins. SP-sLip absorb plasma apolipoproteins A1, E and J, consequently exposing receptor-binding domain of apolipoproteins to achieve brain-targeted delivery. Doxorubicin loaded SP-sLip (SP-sLip/DOX) show significant enhancement of brain distribution and anti-brain cancer effect in comparison to doxorubicin loaded plain liposomes. SP-sLip preserve functions of the absorbed human plasma ApoE, and the corona-mediated targeting strategy works in SP modified PLGA nanoparticles. The present study may pave a new avenue to facilitate clinical translation of targeted drug delivery systems.

/pdf/brain-targeted-drug-delivery-by-manipulating-protein-corona-38n9ez58ux.pdf

Ignacio Salvo

Papers

Formation of the Protein Corona: The Interface between Nanoparticles and the Immune System.