Wound infection is a primary factor contributing to the chronic non-healing of wounds. It triggers inflammatory responses, tissue necrosis, and delays the repair process. Traditional diagnostic methods rely on manual sampling and laboratory testing, which suffer from issues such as prolonged detection cycles, high costs, and poor real-time performance. In recent years, with advancements in electrochemical sensing, optical detection, microfluidic chips, and flexible electronics, real-time monitoring systems based on wearable multi-channel sensing have gradually emerged. These systems can continuously detect wound exudate pH, temperature, inflammatory proteins, metabolites, and other parameters at the wound site, enabling quantitative and intelligent monitoring of infection status. They further allow for necessary interventions to promote wound recovery and healing.
This review systematically summarizes the recent technological advancements in real-time wound infection monitoring, with a focus on biomarker detection strategies, classification of sensing mechanisms, and the technical integration of multi-channel sensors, providing a comprehensive reference for the application of smart wearable biosensors in clinical wound management.
Based on the characteristics of different wound biomarkers, sensors for wound infection assessment can be categorized into three main types according to monitoring methods: colorimetry, fluorescence, and electrochemistry. This article reviews the applications of sensors employing various monitoring methods in detecting different wound infection biomarkers. A comparative analysis is conducted from dimensions such as real-time capability, continuity, data accuracy, and practical application effectiveness, with a focus on the advantages and disadvantages of single-factor versus multi-channel monitoring strategies. The study further discusses research progress in real-time wound infection monitoring using single-factor and multi-channel sensors, and based on the classification and integration of monitoring strategies, provides insights into future directions for real-time wound infection monitoring.
(1) Single-factor monitoring technology
The article first summarizes three typical single-factor sensing modes:
colorimetric sensing
Colorimetry is an intuitive detection method based on the color reactions of chromogenic compounds, where the results can be directly observed and monitored with the naked eye. Multiple reaction markers at wound sites can be monitored using colorimetry, with pH being a typical marker among them. By assessing infection status through color changes, this method offers advantages such as low cost and ease of observation.
Fluorescent sensing
Fluorescent sensors detect wound infection status by responding to specific biomarkers or bacterial metabolites through fluorescent molecules or nanomaterials. These sensors can intuitively reflect infection conditions by changes in intensity caused by fluorescence quenching or enhancement when detecting wound biomarkers. Fluorescent sensing offers advantages such as high sensitivity, rapid response, selective recognition, and visual detection.
Electronics sensing
Single-factor colorimetry and fluorescence methods for wound monitoring offer advantages such as visualization, high sensitivity, and convenience. However, optical-based monitoring cannot directly obtain precise values of the target substances. In such cases, electrochemical monitoring can provide more accurate wound infection information. Electrochemical sensors detect changes in charge distribution on the electrode surface based on principles of potential, current, or impedance transduction, enabling highly sensitive and specific detection of target substances in complex wound environments.
However, as the chemical composition and biomarkers of wound exudate change during the healing process, monitoring a single factor can reflect whether the wound is infected, but underlying pathophysiological factors may interfere with normal healing and affect the assessment of wound infection. In contrast, monitoring multiple factors can provide multidimensional personalized information for wound management. Therefore, multichannel biosensing technology based on multifactorial detection enables more accurate assessment of wound infection status.
（2） Multi factor monitoring strategy
Currently, colorimetric biosensors used for multi-channel monitoring are mostly limited to monitoring a single wound indicator.
However, with the development of technology, researchers are gradually shifting their focus to simultaneously monitoring multiple indicators to comprehensively analyze the infection status of wounds. By preparing an intelligent colorimetric microneedle, iron ion gallic acid coordination polymer nanodots (FND) were integrated onto the microneedle patch, and the pH dependent peroxidase activity of FND was utilized to simulate changes in pH and H ₂ O ₂ concentration through color changes. When the pH value decreases, the sensor color becomes lighter. The researchers further simulated the wound microenvironment of methicillin-resistant Staphylococcus aureus infection (100 µ M H ₂ O ₂, pH 5.5) and observed that the sensor color gradually became lighter over time; In the control group simulating uninfected wounds (100 µ M H ₂ O ₂, pH 7.4), no color response with time was observed. This study successfully distinguished between normal wounds and infected wounds.
Electrochemical biosensors for multi-channel monitoring have been successfully applied in real-time multi factor monitoring of wound infections in recent years. Chen et al. designed an integrated three channel screen printed electrode (iSPE) that can synergistically monitor uric acid (UA), pH, and C-reactive protein (CRP). In addition, with the enhancement of wound infection monitoring capabilities, more indicators can be monitored based on the specific stage of wound healing to provide more comprehensive wound dynamic information. For example, monitoring inflammatory responses by assessing the concentrations of inflammatory mediators such as TNF - α, IL-6, and IL-8; By monitoring the concentration of TGF - β 1, we can understand the skin healing during the wound proliferation phase. By comprehensively monitoring the physiological environment, inflammation, and infection status of the wound, real-time dynamic information on wound healing can be obtained, providing a basis for targeted intervention and treatment.
Source: Sensor Expert Network