Advancements in 3D-printable polysaccharides, proteins, and synthetic polymers for wound dressing and skin scaffolding - A review.

This review investigates the most recent advances in personalized 3D-printed wound dressings and skin scaffolding. Skin is the largest and most vulnerable organ in the human body. The human body has natural mechanisms to restore damaged skin through several overlapping stages. However, the natural wound healing process can be rendered insufficient due to severe wounds or disturbances in the healing process. Wound dressings are crucial in providing a protective barrier against the external environment, accelerating healing. Although used for many years, conventional wound dressings are neither tailored to individual circumstances nor specific to wound conditions. To address the shortcomings of conventional dressings, skin scaffolding can be used for skin regeneration and wound healing. This review thoroughly investigates polysaccharides (e.g., chitosan, Hyaluronic acid (HA)), proteins (e.g., collagen, silk), synthetic polymers (e.g., Polycaprolactone (PCL), Poly lactide-co-glycolic acid (PLGA), Polylactic acid (PLA)), as well as nanocomposites (e.g., silver nano particles and clay materials) for wound healing applications and successfully 3D printed wound dressings. It discusses the importance of combining various biomaterials to enhance their beneficial characteristics and mitigate their drawbacks. Different 3D printing fabrication techniques used in developing personalized wound dressings are reviewed, highlighting the advantages and limitations of each method. This paper emphasizes the exceptional versatility of 3D printing techniques in advancing wound healing treatments. Finally, the review provides recommendations and future directions for further research in wound dressings.

Development of N,O-Carboxymethyl Chitosan-Starch Biomaterial Inks for 3D Printed Wound Dressing Applications.

In this paper, a novel hybrid biomaterial ink consisting of two water-soluble polymers is investigated: starch and N,O-carboxymethyl chitosan (NOCC). The biomaterial ink is used to fabricate controlled release biodegradable wound dressing scaffolds via a novel low-temperature solvent (organic)-free 3D printing technique. NOCC is a variant of chitosan with a high degradation rate that can lead to an immediate release of the drugs, and starch, on the other hand, is used to alter degradation and drug release characteristics of the biomaterial. Mupirocin, a topical anti-infective, is incorporated into the biomaterial inks. Different biomaterial inks in terms of NOCC to starch ratio are prepared and characterized. Printability and rheology of the samples are investigated, and the release of mupirocin over time is quantified. The efficacy of the developed 3D printed wound dressings against Staphylococcus aureus is examined through disk diffusion assays. Increasing NOCC accelerated the release of the drug from the scaffold and led to larger zones of inhibition in the early hours of the in vitro tests; this phenomenon is correlated to the enhanced hydrophilicity of NOCC-dominated scaffolds. The drug release and the zone of inhibition are controlled by altering starch to NOCC ratio in the biomaterial ink.

Development of 3D Printed Drug-Eluting Scaffolds for Preventing Piercing Infection.

Herein, novel drug-eluting, bio-absorbable scaffold intended to cover piercing studs is introduced. This "biopierce" will stay in human tissue following piercing, and will slowly release an antimicrobial agent to prevent infection while the wound heals. Nearly 20% of all piercings lead to local infection. Therefore, it is imperative to develop alternative methods of piercing aftercare to prevent infection. Biopierces were made using mupirocin loaded poly-lactic-co-glycolic acid (PLGA) biomaterial ink, and a low-temperature 3D printing technique was used to fabricate the biopierces. Proton nuclear magnetic resonance (1H NMR) spectroscopy was used to confirm the complete removal of the solvent, and liquid chromatography high-resolution mass spectrometry (LC-HRMS) was used to confirm the structural integrity of mupirocin and to quantify the amount of the released drug over time. The efficacy of the biopierces against Staphylococcus aureus, one of the most common piercing-site pathogens, was confirmed over two weeks using in vitro antimicrobial susceptibility testing.

Development of a Disposable Single-Nozzle Printhead for 3D Bioprinting of Continuous Multi-Material Constructs.

Fabricating multi-cell constructs in complex geometries is essential in the field of tissue engineering, and three-dimensional (3D) bioprinting is widely used for this purpose. To enhance the biological and mechanical integrity of the printed constructs, continuous single-nozzle printing is required. In this paper, a novel single-nozzle printhead for 3D bioprinting of multi-material constructs was developed and characterized. The single-nozzle multi-material bioprinting was achieved via a disposable, inexpensive, multi-fuse IV extension set; the printhead can print up to four different biomaterials. The transition distance of the developed printhead was characterized over a range of pressures and needle inner diameters. Finally, the transition distance was decreased by applying a silicon coating to the inner channels of the printhead.

Low-temperature solvent-based 3D printing of PLGA: a parametric printability study.

In this paper, a novel low-temperature 3 D printing technique is introduced and characterized through a parametric printability study to fabricate poly-lactic-co-glycolic acid (PLGA) constructs using methyl ethyl ketone (MEK) as a solvent. The effects of varying concentrations of PLGA in MEK solvent, lactic to glycolic ratio of PLGA, the molecular weight of PLGA, and the scaling of PLGA constructs on the printability are investigated. PLGA concentrations of higher than 80% w/v, lactic to glycolic ratio more than 75%, molecular weight more than 100 kDa, and printing through nozzles smaller than 0.96 mm internal diameter are recommended for 3 D printing of PLGA constructs with high shape fidelity. Ultimately, a vacuum drying solvent removal process is implemented, and Proton Nuclear Magnetic Resonance (1H-NMR) spectroscopy is used to confirm complete removal of the solvent from PLGA constructs. The results of this study can be used for the development of drug-eluting implants.