Dequan Zhang

Repairing full-thickness skin defects is a major challenge in clinical practice. Three-dimensional (3D) bioprinting of living cells and biomaterials is a promising technique to resolve this challenge. However, the time-consuming preparation and limited sources of biomaterials are bottlenecks that must be addressed. Therefore, we developed a simple and fast method to directly process adipose tissue into a microfragmented adipose extracellular matrix (mFAECM) as the main component of bioink to fabricate 3D-bioprinted, biomimetic, multilayer implants. The mFAECM retained most of the collagen and sulfated glycosaminoglycans in the native tissue. In vitro, the mFAECM composite demonstrated biocompatibility, printability, and fidelity and could support cell adhesion. In a full-thickness skin defect model in nude mice, cells encapsulated in the implant survived and participated in wound repair after implantation. The basic structures of the implant were maintained throughout wound healing and gradually metabolized. The biomimetic multilayer implants fabricated via mFAECM composite bioinks and cells could accelerate wound healing by promoting the contraction of new tissue inside the wound, collagen secretion and remodeling, and neovascularization. This study provides an approach for improving the timeliness of fabricating 3D-bioprinted skin substitutes and may offer a useful tool for treating full-thickness skin defects.

Summary: The objective of this study was to investigate the effect of chilling rate on heat shock proteins (HSP) abundance, myofibrillar proteins degradation and caspase‐3 activity of lamb muscle in postmortem. Eighteen longissimus dorsi (LD) muscles from lamb were treated under three different chilling rates—very fast chilling I (VFC‐I, 22.2 °C h⁻¹), very fast chilling II (VFC‐II, 32.4 °C h⁻¹) and control (1.44 °C h⁻¹)—and stored at −1 °C, −1 °C and 4 °C for 120 h postmortem, respectively. The results showed that myofibril fragmentation index (MFI), the abundance of αβ‐crystallin and HSP20, as well as the degradation of HSP27, HSP70, troponin‐T and desmin under the VFC‐I and VFC‐II groups were higher than control. Notably, HSP90 abundance may not be affected by the chilling rate in the late postmortem aging. Additionally, with increasing of chilling rate for postmortem muscle could inhibit caspase‐3 activity. Overall, results indicated that chilling rate may affect the process of meat tenderization by changing the abundance levels of heat shock proteins, myofibrillar degradation and apoptotic pathway.

Trichosporon asahiiis the major pathogen causing invasive trichosporonosis. Conventional methods of its detection are time-consuming or costly and often require complex DNA extraction and purification steps, which hinders rapid clinical diagnosis. In this study, we evaluated colony PCR, which directly uses colonies or trace clinical samples as the template for amplification, for rapid detection ofT. asahiiinfection. Four methods, namely, direct colony, freeze-thaw, glass beads, and enzymolysis, were compared to select the best DNA extraction strategy. We subsequently designed and screened species-specific primers targeting the intergenic spacer 1 (IGS1) of the ribosomal DNA ofT. asahiiand used them to detect mock infection clinical samples. The species-specific colony PCR based on glass beads proved advantageous, with short procedure time (154.8 ± 0.6 min), good sensitivity (detection limit, 10²CFU/mL), and specificity forT. asahii, indicating that this method can be used for the rapid and simple identification of clinical samples ofT. asahiiinfection.