  Next generation wound care technology capable of diagnosing wound parameters,
promoting healthy cell growth and reducing pathogenic infections noninvasively
will provide patients with an improved standard of care and an accelerated
wound repair. Temperature is one of the indicating biomarkers specific to
chronic wounds. This work reports a hybrid, multifunctional optical platform:
nanodiamond-silk membranes as bioinspired dressings capable of temperature
sensing and wound healing. The hybrid was fabricated through electrospinning
and formed sub-micron fibrous membranes with high porosity. The silk fibres are
capable of compensating for the lack of extracellular matrix at the wound site,
supporting the wound healing. The negatively charged nitrogen vacancy (NV-)
color centres in nanodiamonds (NDs) exhibit optically detected magnetic
resonance (ODMR) properties and act as fluorescent nanoscale thermometers,
capable of sensing temperature variations associated to the presence of
infection or inflammation in a wound, without physically removing the dressing.
Our results show that the presence of NDs in the hybrid ND-silk membranes
improve the thermal stability of silk fibres. The NV- color centres in NDs
embedded in silk fibres exhibit well-retained fluorescent and ODMR. Using the
NV- centres as fluorescent nanoscale thermometers, we achieved temperature
sensing at a range of temperatures, including the biologically relevant
temperature window, on cell-cultured ND-silk membranes. Enhancement in the
temperature sensitivity of the NV- centres was observed for the hybrids. The
membranes were further tested in vivo in a murine wound healing model and
demonstrated biocompatibility and equivalent wound closure rates as the control
wounds. Additionally, the hybrid ND-silk membranes showed selective antifouling
and biocidal propensity toward Gram-negative Pseudomonas aeruginosa and
Escherichia coli.
