The presence of an infection in a wound site is typically diagnosed based on the external appearance, such as redness, swelling, odour, and/or loss of function. However, this can lead to inaccurate and untimely diagnoses, since an infection might be present without obvious symptoms. This would commonly require removal of any dressing that might be present, which can cause further pain to the patient. Therefore, there is a need for more precise methods of detecting infections, with minimal effects to the patient. Comparison of temperature differences between infected tissue and healthy tissue shows an increase ranging from 3-4 °C, while normal skin has a temperature gradient of ±1 °C. Hence, monitoring temperature of wounds can be used to detect the presence of an infection. Nanodiamonds (NDs) containing negatively charged nitrogen-vacancy (NV-) centres are capable of monitoring changes in temperature with minimal influence by environmental factors such as pH, ion concentration or molecular interaction. This study looks at encapsulating these NDs into silk fibres for use as a wound dressing that can monitor temperature changes in the wound, without requiring the removal of the dressing. To further enhance the wound healing and anti-bacterial properties, curcumin was also incorporated into the silk fibres. Curcumin is one of the active ingredients in turmeric and is known to significantly enhance wound healing through its anti-inflammatory and antibacterial properties. This study used this curcumin-nanodiamond-silk hybrid wound dressing to investigate the healing capabilities and temperature sensing properties for use as a wound dressing.
We demonstrate in-vivo chemical sensing using silk-coated exposed-core microstructured optical fibers (ECFs). The ECF provides advantages in sensitivity due to the direct access of the fiber core to the surrounding environment with integrated measurement along the entire fiber length, rather than simply the fiber tip as is common in other probes. The silk coating provides an encapsulation of the sensor molecules, and is well known as a biocompatible material. This deployable fiber sensor is fabricated with simple splicing and coating techniques, making it practical to be used in a range of biomedical sensing applications, which we demonstrate through pH sensing in a mouse model.
This work reports nanodiamond-silk membranes as an optical platform for biosensing and cell growth applications. The hybrid structure was fabricated through electrospinning and mimics a 2D scaffold with high porosity. The negatively charged nitrogen vacancy (NV-) centres in diamond exhibits optically detected magnetic resonance (ODMR), which enables sensing of temperature variations. The NV- centre, as reported in literature, provides a shift of 74 kHz in the ODMR frequency per degree rise in temperature. For our hybrid membranes, we have however observed that the embedded NV- centre provide a greater shift of 95±5 kHz/K in the ODMR frequency. This higher shift in the frequency will result in improved temperature sensitivity enabling the tracking of thermal variations in the biologically relevant window of 25-50 ºC. The thermal conductivity of silk and diamond-silk hybrid will be explored to investigate this enhanced temperature sensing ability of diamond. The hybrid diamond-silk membranes are found to be hydrophilic with a contact angle of (65±2)º. The biocompatibility of the membranes is tested both in vitro in skin keratinocyte (HaCaT) cells and in vivo in a live mouse wound model. The membranes did not induce any toxicity to the cell growth and survival. Moreover, we observed resistance towards the growth and attachment of bacteria.