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International Journal of Bioprinting Bioprinting in diabetic foot disease

channels in a high-cell-density matrix through embedded 4. Bioprinting applications for unique
printing. This study indicated that embedded bioprinting diabetic foot disease characteristics
can be used to create functional tissue or organ structures,
especially vascular structures, and has broad application In 2019, the International Working Group on the Diabetic
prospects in the field of regenerative medicine, especially Foot (IWGDF) proposed eight key factors of the diabetic
in the treatment of DFU chronic wounds in patients with foot classification score based on a literature review and
angiogenic disorders [102-103] . expert opinions to provide guidance for the management
To produce customized tissue-engineered skin for of DFU infection and the blood circulation reconstruction,
although they believe that there is still no classification that
chronic and irregular wound treatment, Wu et al. [104] can predict the outcome of a single ulcer (Figure 2) [107] . The
developed a planar/curved bioprintable hydrogel. The main eight factors are end-stage renal disease, peripheral
hydrogel was composed of polyurethane and gelatin and arterial disease, loss of protective sensation, infection ,
contained three kinds of cells: fibroblasts, keratinocytes, depth, location (forefoot/hindfoot), size of ulcers, and
and endothelial progenitor cells [104] . Moreover, this curved number (single/multiple) of ulcers [107] . In addition, the
bioprintable hydrogel with three cell types could promote chronic wounds of patients with diabetic foot disease also
complete repair of chronic irregular wound in a rat model have a unique high-glucose environment that affects wound
after 28 days, which proved the enormous application healing [108] . To treat DFU wounds using bioprinting, new
potential of this hydrogel that allows customization treatment options tailored to the characteristics of DFU
according to wound shape in chronic wound healing [104] . wounds should be developed.
The integrated development of in situ printing technology
and bioprinting systems mentioned above also meets the Here, we introduce recent bioprinting applications for
requirements of on-site on-demand production and rapid unique diabetic foot disease characteristics in detail.
treatment in the future [104-105] .
Usually, DFU patients have significant differences in 4.1. Imaging and algorithm technology-assisted
wound depth [15] . Therefore, DFU may involve repairing bioprinting for DFU treatment
different types of tissue interfaces [106] . The organizational Traditional imaging methods, such as 3D magnetic
interface is a key structure in coordinating the interaction resonance imaging (MRI), are used to evaluate the blood
[10,107]
between two different organizations, and the possible circulation of DFU wounds . To further enhance the
damage to the organizational interface that may occur ability of bioprinting to accurately evaluate DFU wounds
in DFU patients including skin, neurovascular/muscular and reconstruct biomimetic tissues, more auxiliary imaging
[109-112]
interfaces, and even cartilage–bone interfaces [10,106] . The and modeling methods have been developed .
[109]
self-healing ability of these organizational interfaces Tian et al. proposed to quantitatively describe the 3D
is usually limited [106] . Transplantation of autologous, structure of skin collagen tissue using fractal dimension
allogeneic, or synthetic grafts is currently being used analysis after analyzing skin under different pathological
[110]
to treat tissue interfaces with limited effectiveness [13,15] , conditions. Xu et al. subsequently used small angle
mainly due to the inability to form multilayer structures X-ray scattering (SAXS) combined with the potential
similar to tissue interfaces in a short period of time [106] . fractal characteristics of collagen to design a analysis tool
Computer-assisted bioprinting technology makes for quantitating collagen to evaluate dermis and grafts and
it possible for various biomaterials to be accurately verified the analysis effect in a diabetic mouse model. In
[111]
arranged layer by layer in space [102-103] . The use of addition, Pena et al. used two infrared cameras and an
biomaterials such as cells and cytokines for personalized infrared projector to form a WoundVue camera for initial
modeling and printing of patient wounds has great DFU wound measurement and periodic detection and
application prospects in DFU wound interface tissue evaluated the reliability of the camera by comparing the
repair [106] . However, the current physical and chemical wound area, depth, and other indicators measured by the
[112]
properties of biomaterials and the accuracy of bioprinting camera and an established Visitrak system. Parsa et al.
methods cannot meet the requirements for repairing proposed that optical coherence tomography (OCT) can
complex tissue interface structures [106] . Although be used to evaluate DFU wound characteristics and blood
bioprinting can build nanoscale constructs, it cannot flow through a single-center nonrandomized observational
simultaneously maintain the activity of seed cells and study to improve guidance for treatment option selection.
the microenvironment [106] . Therefore, further studies to Algorithm-assisted bioprinting is also a new strategy
explore suitable biomaterials and bioprinting strategies for improving the therapeutic effect of bioprinting on
for repairing tissue interfaces through bioprinting are DFU wounds [113-117] . Li et al. [114] developed a step-by-
warranted in the future. step algorithm that combined adaptive mesh generation

Volume 9 Issue 6 (2023) 229 https://doi.org/10.36922/ijb.0142