Overcoming biological barriers to improve treatment of a Staphylococcus aureus wound infection

Amoeba-Inspired Soft Robot for Integrated Tumor/Infection Therapy and Painless Postoperative Drainage

Tumor recurrence and wound infection are devastating complications of wide excision surgery for melanoma, and deep postoperative wound drainage typically increases pain. An amoeba-inspired magnetic soft robot (ASR) with switchable dormant and active phases is developed to address the aforementioned challenges. The dormant ASR supports wounds through its solid-like elasticity and regulates reactive oxygen species (ROS) levels bidirectionally, promoting healing in infected wounds and eliminating residual tumors. It solves the challenge caused by the contradictory need for ROS scavenging in wound healing and ROS amplification in tumor/infection management. The active ASR removes absorbed wound exudate by crawling out from irregular wounds; interestingly, this crawling motion prevents damage to fragile tissues and alleviates wound pain via "non-direct friction." More importantly, ASR switches different states in response to an alternating magnetic field owing to its magnetothermal properties, and this process also exerts synergistic antitumor and bacteriostatic effects. Due to the appropriate mechanical structure (cohesive force) of ASR, the content of magnetic nanoparticles required to drive the ASR is ten-fold lower than that of conventional magnetic soft robots, enabling in vivo degradation. These outcomes highlight the vantage of the ASR for treating post-tumor excision wounds and underscore their potential for clinical application.

Ultrasound-Mediated Antibiotic Delivery to In Vivo Biofilm Infections: A Review

Bacterial biofilms are a significant concern in various medical contexts due to their resilience to our immune system as well as antibiotic therapy. Biofilms often require surgical removal and frequently lead to recurrent or chronic infections. Therefore, there is an urgent need for improved strategies to treat biofilm infections. Ultrasound-mediated drug delivery is a technique that combines ultrasound application, often with the administration of acoustically-active agents, to enhance drug delivery to specific target tissues or cells within the body. This method involves using ultrasound waves to assist in the transportation or activation of medications, improving their penetration, distribution, and efficacy at the desired site. The advantages of ultrasound-mediated drug delivery include targeted and localized delivery, reduced systemic side effects, and improved efficacy of the drug at lower doses. This review scrutinizes recent advances in the application of ultrasound-mediated drug delivery for treating biofilm infections, focusing on in vivo studies. We examine the strengths and limitations of this technology in the context of wound infections, device-associated infections, lung infections and abscesses, and discuss current gaps in knowledge and clinical translation considerations.

Smart wireless flexible bandage containing drug loaded polycaprolactone microparticles for real-time monitoring and treatment of chronic wounds

The quality of life is negatively impacted by chronic wounds for more than 25 million people in the US. They are quite prone to infection, which may lead to the eventual loss of a limb. By exposing the ulcers to treatment agents at the appropriate time, the healing rate is increased. On-demand drug release in a closed-loop system will aid us in reaching our goal. In this study, we have developed a platform capable of real-time diagnosis of bacterial infection by wirelessly reading wound pH, as well as slow and on-demand local administration of antibiotics. The drug carrier microparticles, an electrical patch, a thermoresponsive hydrogel with an integrated microheater, and a flexible pH sensor comprised the closed-loop patch. Here it is reported that slow and smart release of cefazolin can be addressed by incorporation of drug encapsulated hydrophobic microparticles embedded into a thermo-responsive hydrogel. The utilization of a programmable bandage to provide antibiotic medication highlights the need of not only choosing appropriate therapeutic substances but also the controlled release of the medicine and its rate of release within the wound area. The results of our study indicate that the use of cefazolin encapsulated polycaprolactone (PCL) microparticles can effectively regulate the application of antibiotic treatment for chronic skin wounds. The results also showed a substantial gradual release of cefazolin from the thermo-responsive Pnipam hydrogel when the wound dressing was subjected to a temperature of 37°C. We believe that the developed flexible smart bandage can have a significant impact on chronic wound healing.

Synergistic Cellular Responses Conferred by Concurrent Optical and Magnetic Stimulation Are Attenuated by Simultaneous Exposure to Streptomycin: An Antibiotic Dilemma

Concurrent optical and magnetic stimulation (COMS) combines extremely low-frequency electromagnetic and light exposure for enhanced wound healing. We investigated the potential mechanistic synergism between the magnetic and light components of COMS by comparing their individual and combined cellular responses. Lone magnetic field exposure produced greater enhancements in cell proliferation than light alone, yet the combined effects of magnetic fields and light were supra-additive of the individual responses. Reactive oxygen species were incrementally reduced by exposure to light, magnetics fields, and their combination, wherein statistical significance was only achieved by the combined COMS modality. By contrast, ATP production was most greatly enhanced by magnetic exposure in combination with light, indicating that mitochondrial respiratory efficiency was improved by the combination of magnetic fields plus light. Protein expression pertaining to cell proliferation was preferentially enhanced by the COMS modality, as were the protein levels of the TRPC1 cation channel that had been previously implicated as part of a calcium-mitochondrial signaling axis invoked by electromagnetic exposure and necessary for proliferation. These results indicate that light facilitates functional synergism with magnetic fields that ultimately impinge on mitochondria-dependent developmental responses. Aminoglycoside antibiotics (AGAs) have been previously shown to inhibit TRPC1-mediated magnetotransduction, whereas their influence over photomodulation has not been explored. Streptomycin applied during exposure to light, magnetic fields, or COMS reduced their respective proliferation enhancements, whereas streptomycin added after the exposure did not. Magnetic field exposure and the COMS modality were capable of partially overcoming the antagonism of proliferation produced by streptomycin treatment, whereas light alone was not. The antagonism of photon-electromagnetic effects by streptomycin implicates TRPC1-mediated calcium entry in both magnetotransduction and photomodulation. Avoiding the prophylactic use of AGAs during COMS therapy will be crucial for maintaining clinical efficacy and is a common concern in most other electromagnetic regenerative paradigms.

Formulation of novel bioactive gelatin inspired by cinnamaldehyde for combating multi-drug resistant bacteria: Characterization, molecular docking, pharmacokinetic analyses, and in vitro assessments

This study set out to formulate antibacterial and antioxidant gelatin boosted by cinnamaldehyde for combating multi-drug resistant bacteria previously obtained from chronic wounds. Towards this end, gelatin amine groups were conjugated with carbonyl groups of cinnamaldehyde, producing cinnamyl-gelatin Schiff bases. The physicochemical attributes of cinnamyl-gelatin Schiff bases were probed concerning alterations in chemical structures and microstructures compared to native gelatin. Besides, cinnamyl-gelatin Schiff bases exhibited higher thermal stability than gelatin, with a diminishing in solubility due to increases in hydrophobicity features. Interestingly, cinnamyl-gelatin derivatives exerted antibacterial activities versus multi-drug resistant Gram-negative and Gram-positive bacteria, showing maximum growth inhibition at the highest concentration of cinnamaldehyde incorporated into gelatin. The scavenging activities of gelatin against DPPH and ABTS•+ were promoted in cinnamyl-gelatin derivatives from 11.93 ± 0.6 % to 49.9 ± 2.5 % and 12.54 ± 0.63 % to 49.9 ± 3.12 %, respectively. Remarkably, cinnamyl-gelatin derivatives induced the proliferation of fibroblast cells, implying their prospective applications in tissue engineering. Molecular docking and pharmacokinetic investigations disclosed the potential antibacterial mechanisms of cinnamyl-gelatin derivatives alongside their biopharmaceutical applications. Altogether, these findings suggest that cinnamyl-gelatin derivatives could be utilized to tailor antibacterial-free antibiotics and antioxidant wound dressings against virulent bacteria to promote chronic wound recovery.

Strategies and materials for the prevention and treatment of biofilms

Biofilms are aggregates of organized microbial growth that function as barriers and create a stable internal environment for cell survival. The bacteria in the biofilms exhibit characteristics that are quite different from the planktonic bacteria, such as strong resistance to antibiotics and other bactericides, getting out of host immunity, and developing in harsh environments, which all contribute to the persistent and intractable treatment. Hence, there is an urgent need to develop novel materials and strategies to combat biofilms. However, most of the reviews on anti-biofilms published in recent years are based on specific fields or materials. Microorganisms are ubiquitous, except in the context of medical and health issues; however, biofilms exert detrimental effects on the advancement and progress of various fields. Therefore, this review aims to provide a comprehensive summary of effective strategies and methodologies applicable across all industries. Firstly, the process of biofilms formation was introduced to enhance our comprehension of the "enemy". Secondly, strategies to intervene in the important links of biofilms formation were discussed, taking timely action during the early weak stages of the "enemy". Thirdly, treatment strategies for mature biofilms were summarized to deal with biofilms that break through the defense line. Finally, several substances with antibacterial properties were presented. The review concludes with the standpoint of the author about potential developments of anti-biofilms strategies. This review may help researchers quickly understand the research progress and challenges in the field of anti-biofilms to design more efficient methods and strategies to combat biofilms.