Dual functional β-peptide polymer-modified resin beads for bacterial killing and endotoxin adsorption

Smart 3D Printed Hydrogel Skin Wound Bandages: A Review

Wounds are a major health concern affecting the lives of millions of people. Some wounds may pass a threshold diameter to become unrecoverable by themselves. These wounds become chronic and may even lead to mortality. Recently, 3D printing technology, in association with biocompatible hydrogels, has emerged as a promising platform for developing smart wound dressings, overcoming several challenges. 3D printed wound dressings can be loaded with a variety of items, such as antibiotics, antibacterial nanoparticles, and other drugs that can accelerate wound healing rate. 3D printing is computerized, allowing each level of the printed part to be fully controlled in situ to produce the dressings desired. In this review, recent developments in hydrogel-based wound dressings made using 3D printing are covered. The most common biosensors integrated with 3D printed hydrogels for wound dressing applications are comprehensively discussed. Fundamental challenges for 3D printing and future prospects are highlighted. Additionally, some related nanomaterial-based hydrogels are recommended for future consideration.

Programmable immune activating electrospun fibers for skin regeneration

Immune cells play a crucial regulatory role in inflammatory phase and proliferative phase during skin healing. How to programmatically activate sequential immune responses is the key for scarless skin regeneration. In this study, an "Inner-Outer" IL-10-loaded electrospun fiber with cascade release behavior was constructed. During the inflammatory phase, the electrospun fiber released a lower concentration of IL-10 within the wound, inhibiting excessive recruitment of inflammatory cells and polarizing macrophages into anti-inflammatory phenotype "M2c" to suppress excessive inflammation response. During the proliferative phase, a higher concentration of IL-10 released by the fiber and the anti-fibrotic cytokines secreted by polarized "M2c" directly acted on dermal fibroblasts to simultaneously inhibit extracellular matrix overdeposition and promote fibroblast migration. The "Inner-Outer" IL-10-loaded electrospun fiber programmatically activated the sequential immune responses during wound healing and led to scarless skin regeneration, which is a promising immunomodulatory biomaterial with great potential for promoting complete tissue regeneration.

Hepatic cell-sheet fabrication of differentiated mesenchymal stem cells using decellularized extracellular matrix and thermoresponsive polymer

PURPOSE

Liver tissue engineering via cell sheet technology would open new doors for treatment of patients with liver failure. Decellularized tissues could provide sufficient extracellular matrix (ECM) to support development of hepatocytes in in vivo niches. Besides, with the potential of temperature responsive polymer (pNIPAAm) as an intelligent surface for controlling the attachment/detachment of cell, we set out to generate three in vitro microenvironments models including I: pNIPAAm hydrogel (pN hydrogel), II: decellularized ECM incorporated into pNIPAAm hydrogel (dECM + pN hydrogel) and III: decellularized ECM scaffold (dECM scaffold) to investigate the structural and function cues of hepatocyte-like cells after differentiation of adipose tissue-derived mesenchymal stem cells (AT-MSCs) on the surface of these models.

METHOD

dECM scaffold was obtained after decellularization of rat liver, and its efficiency was analyzed. pN hydrogel and dECM + pN hydrogel (1:3 and 2:3 ratios) of were fabricated, and scaffold architecture was characterized. Each well of culturing plates was coated separately with these three constructs and AT-MSCs were instructed to differentiate into hepatocyte-like cells (HLCs). After recellularization, patterns of differentiation, and expression of hepatogenic markers were investigated via biochemical assays and qRT-PCR at different time points.

RESULTS

Multipotency of AT-MSCs, after their ability for osteogenesis and adipogenesis was documented. Production of dense and intact cell sheets was reported in dECM + pN hydrogel, as opposed to pN hydrogel and dECM scaffold. Also, statistically significant difference of HLCs functionality in dECM + pN hydrogel was confirmed after evaluation of the expression of hepatocyte markers including, alpha-fetoprotein, cytokeratin 18, cytochrome P450-2E1 and phosphoenolpyruvate carboxykinase.

CONCLUSION

Our results proved dECM + pN hydrogel were able to preserve hepatocyte function in cell sheets owing to the high level of albumin, urea, hepatogenic markers, and glycogenesis potential of HLCs. Accordingly, dECM incorporated in pN hydrogel could remodel microenvironments to guide the AT-MSCs into conducive differentiation and proliferation to give rise to multilayer sheets of cells in their own ECM.

3D-printed assistive pipetting system for gel electrophoresis for technicians with low acuity vision

In molecular biology laboratories, many tasks require fine motor control and high acuity vision. For example, lab technicians with visual impairment experience difficulty loading samples into the small wells of a horizontal agarose gel. We have developed a 3D-printable gel loading system which allows technicians with low-contrast vision to load gels correctly. It includes a casting tray, a bridge, and a modified comb. The system provides a high-contrast visual field to improve visibility, and the bridge allows pipette tips to be inserted at the correct location and only to the correct depth. The necessary computer files for printing this device are freely available to increase the accessibility of molecular biology laboratories to people with visual impairment.

We have produced a system for people with visual impairment to successfully load an agarose gel for gel electrophoresis. This system can be produced using a 3D printer. There are three components: a casting tray, a bridge, and a modified comb. The bridge fits into side notches in the casting tray and is suspended above the tray. The comb is inserted into the bridge while the molten gel is poured. When the gel cools, the comb is removed leaving the bridge in place. Pipettes can then only be inserted in the correct location and to the correct depth to load the wells. Importantly, the bridge and tray are contrasting colors to aid in visual discernment.

Activation of Piezo1 by ultrasonic stimulation and its effect on the permeability of human umbilical vein endothelial cells

The acoustic radiation forces produced by ultrasonic stimulation induce shear stress on objects in the acoustic field. Piezo1, a mechanosensitive ion channel protein that is expressed on the plasma membranes of vertebrate cells, can sense shear stress and transduce it into downstream signaling. In this study, we examined the sensitivity of Piezo1 to ultrasonic stimulation and assessed its downstream biological functions in human umbilical vein endothelial cells (HUVECs). Ultrasonic stimulation using a stimulation power of 0.2 W and a frequency of 1 MHz for 10 s did not induce cell damage. However, ultrasonic stimulation induced an influx of calcium ions, which increased with an increase in the stimulation duration. Knockdown of Piezo1 protein decreased the influx of calcium ions during ultrasonic stimulation, which demonstrated that Piezo1 may be activated by the shear stress produced by ultrasonic stimulation. The influx of calcium ions in response to ultrasonic stimulation could be modulated by the Piezo1 protein level. Additionally, ultrasonic stimulation reduced the levels of downstream factors such as MLCK and ATP, which are involved in the Ca²⁺/CaM/MLCK pathway, by suppressing Piezo1. As the Ca²⁺/CaM/MLCK pathway influences the permeability of the cell membrane, the internalization of FITC-Dextran into cells under ultrasonic stimulation was validated. Ultrasonic stimulation was demonstrated to promote the increase in cell permeability, and the suppression of Piezo1 was shown to induce the decrease in cell permeability. Therefore, this study shows that ultrasonic stimulation may modulate the permeability of the membrane of HUVECs by modulating the expression of Piezo1 protein.

Dual-Core Prebiotic Microcapsule Encapsulating Probiotics for Metabolic Syndrome

Designing strategies to utilize the synergistic effect of probiotics and prebiotics is a promising way in treating metabolic-related diseases. Here, inspired by the mutually promotable but mutually incompatible characteristics of Yin and Yang, dual-core microcapsules that encapsulate Lactobacillus and Bacillus subtilis into separate compartments were presented through electrostatically driven microfluidics. The microcapsules showed acid resistance and preserved probiotic activity. They also fostered the proliferation of probiotics while creating an anaerobic environment and promoted lactic acid fermentation without affecting each other. It has been demonstrated that the microcapsules could reduce inflammation, improve fat metabolism, and restore intestinal barrier functions, thus contributing to the treatment of metabolic syndrome in vivo. These features make the dual-core microcapsules an ideal candidate for treating metabolic syndrome and related diseases.

Alginate hydrogel dressings for advanced wound management

Wound healing is a complicated and continuous process affected by several factors, and it needs an appropriate surrounding to achieve accelerated healing. At present, various wound dressings are used for wound management, such as fiber, sponge, hydrogel, foam, hydrocolloid and so on. Hydrogels can provide mechanical support and moist environment for wounds, and are widely used in biomedical field. Alginate is a natural linear polysaccharide derived from brown algae or bacteria, consisting of repeating units of β-1,4-linked D-mannuronic acid (M) and L-guluronic acid (G) in different ratios. It is widely used in biomedical and engineering fields due to its good biocompatibility and liquid absorption capacity. Alginate-based hydrogels have been used in wound dressing, tissue engineering, and drug delivery applications for decades. In this review, we summarize the recent approaches in the chemical and physical preparation and the application of alginate hydrogels in wound dressings.

Structural design and antimicrobial properties of polypeptides and saccharide–polypeptide conjugates

The development and progress of antimicrobial polypeptides and saccharide–polypeptide conjugates in regards to their structural design, biological functions and antimicrobial mechanism.