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Peripheral Blood Plasma Clot as a Local Antimicrobial Drug Delivery Matrix
Jan Gessmann1,2, Dominik Seybold1,2, Fahim Ayami2
11 Department of Trauma Surgery, BG University Hospital Bergmannsheil, Ruhr University Bochum , Bochum, Germany .
Abstract:
Platelet-free blood plasma clots were loaded either with antibiotics (vancomycin, gentamicin, or linezolid) at concentrations of 5-300 μg/mL or with silver ions (silver acetate) at concentrations of 3.3-129 μg/mL. The release of antibiotics or silver from the clot matrix was analyzed after repeated immersion of the plasma clots using reversed-phase high-performance liquid chromatography (RP-HPLC) or atomic absorption spectroscopy (AAS). The antimicrobial activity was tested against Staphylococcus aureus; tissue cell compatibility was analyzed using human mesenchymal stem cells (hMSC). Fibrin fiber thickness of the clots was analyzed by scanning electron microscopy. While addition of linezolid and vancomycin did not significantly change the fibrin fiber thickness, gentamicin and silver ions led to an increase in fiber thickness. All antibiotics showed a concentration-dependent burst-like release from the plasma clots within 1 h followed by a general decay in elution. The release of vancomycin and gentamicin, or silver lasted up to 7 days (depending on initial concentrations), but lasted only up to 4 h for linezolid. A correlation (p < 0.0001) was noted between the concentration of released antibiotics analyzed by HPLC and antimicrobial activity (agar diffusion test). A decrease in antibacterial activity of gentamicin- and vancomycin-containing clots occurred within 4 or 5 days. In contrast, the corresponding antibacterial activity of plasma clots containing linezolid was limited to 3 h. Antibacterial activity of plasma clots containing silver at the highest concentrations decreased after day 3, but clots with lower concentrations induced incomplete bacterial lysis or displayed no antibacterial activity. The antibiotic-containing clots did not induce cytotoxic effects on the embedded hMSC in contrast to all clots containing silver. Our results indicate that an autologous plasma clot can be used to deliver antibiotics such as vancomycin and gentamicin in combination with hMSC and the antibacterial effects persist for days without inducing cytotoxic effects on the embedded stem cells.
Insights
Autologous plasma clots effectively deliver vancomycin and gentamicin antibiotics, maintaining antibacterial activity for days without harming human mesenchymal stem cells (hMSC). Silver ions also showed antimicrobial effects but were cytotoxic to hMSC.
Area of Science:
- Biomaterials Science
- Drug Delivery Systems
- Tissue Engineering
Background:
- Autologous plasma clots offer a potential scaffold for localized drug delivery.
- Effective antimicrobial strategies are crucial for preventing implant-associated infections.
- Biocompatible drug delivery systems are needed to support tissue regeneration.
Purpose of the Study:
- To evaluate the release kinetics and antimicrobial efficacy of antibiotics (vancomycin, gentamicin, linezolid) and silver ions loaded into autologous plasma clots.
- To assess the impact of these agents on fibrin fiber structure and the biocompatibility with human mesenchymal stem cells (hMSC).
- To determine the duration of antibacterial activity and potential cytotoxicity of the loaded plasma clots.
Main Methods:
- Plasma clots were loaded with vancomycin, gentamicin, linezolid, or silver acetate at varying concentrations.
- Drug and silver ion release was quantified using RP-HPLC and AAS, respectively.
- Antimicrobial activity against Staphylococcus aureus and cytotoxicity on hMSC were assessed. Fibrin structure was analyzed via SEM.
Main Results:
- Vancomycin and gentamicin showed sustained release up to 7 days, while linezolid release was limited to 4 hours.
- Gentamicin and silver ions increased fibrin fiber thickness; linezolid and vancomycin did not.
- Antibiotic-loaded clots demonstrated concentration-dependent antimicrobial activity and were non-cytotoxic to hMSC, whereas silver ions exhibited cytotoxicity.
Conclusions:
- Autologous plasma clots serve as effective carriers for sustained delivery of vancomycin and gentamicin.
- These antibiotic-loaded clots maintain antibacterial efficacy for days without adverse effects on embedded hMSC.
- Silver ions show antimicrobial potential but pose a risk of cytotoxicity, limiting their use in combination with stem cells.
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