Wound Infection Detection Using a Rapid Biomarker.

OBJECTIVE: To evaluate the performance of a rapid, point-of-care diagnostic biomarker that is sensitive to overexpression of gelatinases, the major expressed biomolecules during wound infection. Wound exudate composition and pH are key determinants of infection, and rapid infection detection has an important role in wound healing. METHODS: The biomarker was first investigated for cytotoxic effects, and irritation and sensitization tests were carried out. The biomarker was then tested on 198 patients suffering from different types of wounds. Data including age, sex, wound type, depth, site, etiology, and exudate pH were collected. Wound pH was measured to determine if it could be a possible early indicator of infection, and bacterial wound cultures were performed as a control. RESULTS: Analysis revealed that the biomarker had no cytotoxicity and caused no erythema, edema, or other adverse response. The rapid diagnostic biomarker demonstrated overall clinical sensitivity, specificity, accuracy, positive predictive value, and negative predictive value: 96.84%, 97.5%, 96.96%, 99.35%, and 88.63%, respectively. Moreover, infected wounds had higher pH values according to culture results and nearly 80% of chronic, nonhealing wounds were infected. CONCLUSIONS: This biomarker enables caregivers to detect wound infection in a timely manner and treat it efficiently. Wound pH monitoring may potentially be a useful method for indicating the presence or absence of infection.

The potential impact of carboxylic-functionalized multi-walled carbon nanotubes on trypsin: A Comprehensive spectroscopic and molecular dynamics simulation study.

In this study, we report a detailed experimental, binding free energy calculation and molecular dynamics (MD) simulation investigation of the interactions of carboxylic-functionalized multi-walled carbon nanotubes (COOH-f-MWCNTs) with porcine trypsin (pTry). The enzyme exhibits decreased thermostability at 330K in the presence of COOH-f-MWCNTs. Furthermore, the activity of pTry also decreases in the presence of COOH-f-MWCNTs. The restricted diffusion of the substrate to the active site of the enzyme was observed in the experiment. The MD simulation analysis suggested that this could be because of the blocking of the S1 pocket of pTry, which plays a vital role in the substrate selectivity. The intrinsic fluorescence of pTry is quenched with increase in the COOH-f-MWCNTs concentration. Circular dichroism (CD) and UV-visible absorption spectroscopies indicate the ability of COOH-f-MWCNTs to experience conformational change in the native structure of the enzyme. The binding free energy calculations also show that electrostatics, π-cation, and π-π stacking interactions play important roles in the binding of the carboxylated CNTs with pTry. The MD simulation results demonstrated that the carboxylated CNTs adsorb to the enzyme stronger than the CNT without the-COOH groups. Our observations can provide an example of the nanoscale toxicity of COOH-f-MWCNTs for proteins, which is a critical issue for in vivo application of COOH-f-MWCNTs.