Biofilm-related infections (BRI) are an overwhelming issue for health care systems in Europe and worldwide. BRIs are characterized by a chronic behavior or frequent recurrences, antibiotic resistance, complex and prolonged treatment, poor prognosis, high social and economical costs and difficult diagnosis. Demand in implantable biomedical microsystems, which are used for early detection and diagnosis of diseases is increased and lead to intensive research and innovation in such area. However, there a lack of reliable implantable sensors for detection of onset of bacterial infection. Based on the previous knowledge of research team members and preliminary tests, we will design new type of implantable sensors based either on physical or chemical principles of early biofilm detection.

Infekce spojené s tvorbou biofilmu (BRI) jsou zásadním problémem pro zdravotnictví v Evropě i v celosvětovém měřítku. BRI se vyznačují chronickým chováním nebo častými recidivami, rezistencí na antibiotika, komplexní a dlouhodobou léčbou, špatnou prognózou, vysokými sociálními a ekonomickými náklady a obtížnou diagnózou. Požadavky na implantabilní biomedicínské mikrosystémy, které se používají pro včasné odhalení a diagnostiku nemocí, se zvyšují a vedou k jejich intenzivnímu výzkumu a inovacím. Existuje však nedostatek spolehlivých implantabilních senzorů pro včasnou detekci nástupu bakteriální infekce. Na základě předchozích znalostí členů výzkumných týmů a předběžných zkoušek bude navržen nový typ implantabilních senzorů založených buď na fyzikálních, nebo chemických principech včasné detekce vzniku biofilmu.

• Klíčová slova
• detekce biofilmu, implantable biosensors, detection of colonization, detekce infekce, detection of infection, implantovatelný biosenzory,

• NLK Publikační typ
• závěrečné zprávy o řešení grantu AZV MZ ČR

BACKGROUND: The diagnosis of joint replacement infection is a difficult clinical challenge that often occurs when the implant cannot be salvaged. We hypothesize that the pH value of synovial fluid could be an important indicator of the inflammatory status of the joint. However, in the literature, there is a lack of data on the pH changes in hip and knee joint replacements and their relation to infection and implant failure. In this study, we aimed to measure the pH levels of synovial fluid in patients with hip and knee joint replacements. We also investigated the potential of pH measurement as a diagnostic tool for joint replacement infection. In this study, we recorded the pH values to be 7.55 and 7.46 in patients where Pseudomonas aeruginosa was identified as the cause of the prosthetic joint infection. We attribute this to the different environments created by this specific bacterium. In other cases where the pH was higher, chronic mitigated infections were diagnosed, caused by strains of Staphylococcus aureus, Streptococcus agalactiase, and coagulase negative staphylococcus. MATERIALS AND METHODS: In our cohort of 155 patients with implanted hip (THA; n = 85) or knee (TKA; n = 70) joint replacements, we conducted a prospective study with a pH measurement. Out of the whole cohort, 44 patients had confirmed joint replacement infection (28.4%) (44/155). In 111 patients, infection was ruled out (71.6%) (111/155). Joint replacement infection was classified according to the criteria of the Musculoskeletal Infection Society (MSIS) from 2018. Based on the measured values, we determined the cut-off level for the probability of ongoing inflammation. We also determined the sensitivity and specificity of the measurement. RESULTS: The group of patients with infection (n = 44) had a significantly lower synovial fluid pH (pH = 6.98 ± 0.48) than the group of patients with no infection (n = 111, pH = 7.82 ± 0.29, p < 0.001). The corresponding median pH values were 7.08 for the patients with infection and 7.83 for the patients with no infection. When we determined the cut-off level of pH 7.4, the sensitivity level of infected replacements was 88.6%, and the specificity level of the measurement was 95.5%. The predictive value of a positive test was 88.6%, and the predictive value of a negative test was 95.5%. CONCLUSIONS: Our results confirm that it is appropriate to include a pH measurement in the diagnostic spectrum of hip and knee replacements. This diagnostic approach has the potential to provide continuous in vivo feedback, facilitated by specialized biosensors. The advantage of this method is the future incorporation of a pH-detecting sensor into intelligent knee and hip replacements that will assess pH levels over time. By integrating these biosensors into intelligent implants, the early detection of joint replacement infections could be achieved, enhancing proactive intervention strategies.

• Publikační typ
• časopisecké články MeSH

Jedním z problémů při kloubních náhradách jsou komplikace spojené s pooperačními infekcemi. Infekce způsobené bakteri-emi, které tvoří biofilmy na površích, se nazývají infekce související s biofilmem (biofilm related infections, BRI). V důsledku následné biologické odezvy organismu dochází k silným patofyziologickým změnám vmikroklimatu kolem takto postiženého povrchu (pokles pH, tvorba různých reaktivních forem kyslíku (ROS), vyčerpání iontů železa a zvýšení koncentrace vápenatých iontů). Vytvořili jsme robustní selektivní polymerní potenciometrický senzor ROS a pH senzor pro detekci změn způsobených sterilním zánětem a bakteriálními a plísňovými infekcemi. Senzor ROS se skládá z vodivé polymerní vrstvy na bázi polythiofenu se zabudovaným komplexem porfyrin-kov, který potenciometricky deteguje přítomnost ROS, jak bylo demonstrováno na peroxi-du vodíku. Tento senzor je kovalentně potažen vrstvou odolnou biopasivaci (non-biofouling layer, NBL) tvořenou poly(2-methyl--2-oxazolin)em, která funguje jako biokompatibilizátor.Bylo prokázáno, že potenciometrický senzor vykazuje rychlou odezvu naperoxid vodíku, nezaznamenává interferenci s hovězím sérovým albuminem jako modelovým sérovým proteinem a je schopenplně reverzibilně detegovat ROS s lineární odezvou v širokém rozsahu biologicky relevantních koncentrací (od 0,05μM do10μM). Polymerní pH senzor na bázi polyanilinu a poly(2-methyl-2-oxazolinu) na nosiči z titanové slitiny byl vyvinut pro po-tenciometrickou detekci změn pHv okolí implantátu, aby bylo možné včas detegovat výše uvedené záněty. Vyvinuté elektrody měří změnu pH v rozsahu pH5 až 8, tedy vrozmezí relevantním pro jednotlivé infekce baktériemi a kvasinkami.

One of the problems occurring after the joint replace-ment is connected with the post-surgery infections which are caused by bacteria that form biofilms on surfaces and are referred to as biofilm-related infections (BRI). It is also worth noting that due to the bioresponse, strong path-ophysiologicalchangesinthemicroclimateofanaffectedsurface occur (decrease in pH, formation of various reac-tive oxygen species (ROS), depletion of Fe ions, and in-crease in the concentration of Ca ions). In this work we have prepared a robust selective potentiometric sensorof ROS and pH sensor for the detection of pH changes caused by sterile inflammation and bacterial and fungal infections. The ROS sensor consists of a conductive poly-mer layer based on polythiophene with an incorporated porphyrin-metal complex that potentiometrically detects the presence of ROS (H2O2and ClO–ions). This sensor is connected by the covalent bonds with a non-biofouling layer of poly(2-methyl-2-oxazoline), which works as abio-compa-tibilizer. It was shown that the potentiometric sen-sor shows a rapid response to hydrogen peroxide, does not record any interference with bovine serum albumin as amodel serum protein, and is able to fully reversibly de-tect ROS with a linear response within a wide range of biological relevant concentrations (from 0.05 μM to 10μM). The sensing electrode based on polyaniline and poly(2-methyl-2-oxazoline) on a titanium alloy support was developed for the potentiometric detection of peri-implant pH changes to enable early detection of the afore-mentioned pathologies. The developed electrodes show the changing of pH in the range between 5 and 8 for the individual pathogenic bacteria or pathogenic yeast, with aNernstian slope of −59.6/pH.

• Klíčová slova
• potenciometrický senzor,
• MeSH
• biofilmy MeSH
• klouby chirurgie   mikrobiologie   MeSH
• koncentrace vodíkových iontů MeSH
• lidé MeSH
• potenciometrie * metody   přístrojové vybavení   MeSH
• protézy kloubů mikrobiologie   MeSH
• reaktivní formy kyslíku analýza   MeSH
• výzkum MeSH
• zánět diagnóza   etiologie   prevence a kontrola   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• práce podpořená grantem MeSH
• přehledy MeSH

The main task of the research is to acquire fundamental knowledge about the effect of polymer structure on the physicochemical properties of films. A novel meta-material that can be used in manufacturing sensor layers was developed as a model. At the first stage, poly(sodium 4-styrenesulfonate) (PNaSS) cross-linked microspheres are synthesized (which are based on strong polyelectrolytes containing sulfo groups in each monomer unit), and at the second stage, PNaSS@PEDOT microspheres are formed. The poly(3,4-ethylenedioxythiophene) (PEDOT) shell was obtained by the acid-assisted self-polymerization of the monomer; this process is biologically safe and thus suitable for biomedical applications. The suitability of electrochemical impedance spectroscopy for E. coli detection was tested; it was revealed that the attached bacterial wall was destroyed upon application of constant oxidation potential (higher than 0.5 V), which makes the PNaSS@PEDOT microsphere particles promising materials for the development of antifouling coatings. Furthermore, under open-circuit conditions, the walls of E. coli bacteria were not destroyed, which opens up the possibility of employing such meta-materials as sensor films. Scanning electron microscopy, X-ray photoelectron spectroscopy, water contact angle, and wide-angle X-ray diffraction methods were applied in order to characterize the PNaSS@PEDOT films.

• MeSH
• bicyklické sloučeniny heterocyklické chemie   MeSH
• Escherichia coli * MeSH
• mikrosféry MeSH
• polymery * chemie   MeSH
• Publikační typ
• časopisecké články MeSH