Incorporation of Lignin in Natural and Synthetic Biomaterials to Alter Mechanical and Biochemical Properties for Enhanced Wound Healing

It is estimated that chronic, non-healing wounds affect more than 6.5 million Americans annually, with an estimated healthcare cost beyond $14 billion. Here, we attempted to create composites of natural (collagen type I or gelatin-methacrylate) or synthetic (poly(ethylene glycol) polymers incorporating a natural plant component, lignin, to combat the costs and limitations current wound healing methods face. Three-dimensional matrices of collagen type I (Col I) are widely used in tissue engineering applications for its abundance in many tissues, bioactivity with many cell types, and excellent biocompatibility. Inspired by the structural role of lignin in plant tissue, we found that sodium lignosulfonate (SLS) and an alkali-extracted lignin from switchgrass (SG) increased the stiffness of Col I gels from 52 to 670 Pa and 52 to 320 Pa, respectively, and attenuated shear thinning properties, with the formulation of 1.8 mg/mL Col I and 5.0 mg/mL SLS or SG. In 2D cultures, no cytotoxicity of collagen-SLS to adipose-derived stromal cells was observed and viability was maintained over 7 days. Inspired by thiol-ene chemistry, we hypothesized that thiol functionalization of lignin would allow for chemoselective addition to typical biomaterials, such as gelatin-methacrylate (GelMA) and poly(ethylene glycol (PEG). Addition of TLS, to either biomaterial, showed no significant changes in their viscoelastic properties with the addition of TLS significantly increasing the antioxidant % for both PEG, which contained native antioxidant capacity, and GelMA, essentially of zero antioxidant capacity in its native form. Incorporation of fish GelMA, into PEG-TLS composites, enhanced cell adhesion for HS and LS human dermal fibroblasts (hdFBs) and showed a significant reduction in COL1A1, ACTA2, TGFB1, HIF1A, and HSP27 for HS when compared to LS. GelMA-TLS composites seeded with HS and LS hdFBs showed similar results for COL1A1 and ACTA2 with overexpression leading to fibrosis and reduced wound healing. Additionally, we determined Hsp27 is a critical marker in excess fibrosis, via a fibrosis array, and both gene and protein expression were significantly attenuated when seeded onto GelMA-TLS composites, compared to controls. The work presented here valorizes two waste by-products, lignin and fish gelatin engineered into composites suited for enhanced wound healing applications

Improved Biocompatible, Flexible Mesh Composites for Implant Applications via Hydroxyapatite Coating with Potential for 3Dimensional Extracellular Matrix Network and Bone Regeneration

[Image: see text] Hydroxyapatite (HA)-coated metals are biocompatible composites, which have potential for various applications for bone replacement and regeneration in the human body. In this study, we proposed the design of biocompatible, flexible composite implants by using a metal mesh as substrate and HA coating as bone regenerative stimulant derived from a simple sol–gel method. Experiments were performed to understand the effect of coating method (dip-coating and drop casting), substrate material (titanium and stainless steel) and substrate mesh characteristics (mesh size, weave pattern) on implant’s performance. HA-coated samples were characterized by X-ray diffractometer, transmission electron microscope, field-emission scanning electron microscope, nanoindenter, polarization and electrochemical impedance spectroscopy, and biocompatibility test. Pure or biphasic nanorod HA coating was obtained on mesh substrates with thicknesses varying from 4.0 to 7.9 μm. Different coating procedures and number of layers did not affect crystal structure, shape, or most intense plane reflections of the HA coating. Moduli of elasticity below 18.5 GPa were reported for HA-coated samples, falling within the range of natural skull bone. Coated samples led to at least 90% cell viability and up to 99.5% extracellular matrix coverage into a 3-dimensional network (16.4% to 76.5% higher than bare substrates). Fluorescent imaging showed no antagonistic effect of the coatings on osteogenic differentiation. Finer mesh size enhanced coating coverage and adhesion, but a low number of HA layers was preferable to maintain open mesh areas promoting extracellular matrix formation. Finally, electrochemical behavior studies revealed that, although corrosion protection for HA-coated samples was generally higher than bare samples, galvanic corrosion occurred on some samples. Overall, the results indicated that while HA-coated titanium grade 1 showed the best performance as a potential implant, HA-coated stainless steel 316 with the finest mesh size constitutes an adequate, lower cost alternative

Low-Cost Resin 3-D Printing for Rapid Prototyping of Microdevices: Opportunities for Supporting Aquatic Germplasm Repositories

Germplasm repositories can benefit sustainable aquaculture by supporting genetic improvement, assisted reproduction, and management of valuable genetic resources. Lack of reliable quality management tools has impeded repository development in the past several decades. Microfabricated open-hardware devices have emerged as a new approach to assist repository development by providing standardized quality assessment capabilities to enable routine quality control. However, prototyping of microfabricated devices (microdevices) traditionally relies on photolithography techniques that are costly, time intensive, and accessible only through specialized engineering laboratories. Although resin 3-D printing has been introduced into the microfabrication domain, existing publications focus on customized or high-cost (>thousands of USD) printers. The goal of this report was to identify and call attention to the emerging opportunities to support innovation in microfabrication by use of low-cost (<USD 350) resin 3-D printing for rapid prototyping. We demonstrate that low-cost mask-based stereolithography (MSLA) 3-D printers with straightforward modifications can provide fabrication quality that approaches traditional photolithography techniques. For example, reliable feature sizes of 20 µm with dimensional discrepancy of <4% for lateral dimensions and <5% for vertical dimensions were fabricated with a consumer-level MSLA printers. In addition, alterations made to pre-processing, post-processing, and printer configuration steps improved print quality as demonstrated in objects with sharper edges and smoother surfaces. The prototyping time and cost of resin 3-D printing (3 h with USD 0.5/prototype) were considerably lower than those of traditional photolithography (5 d with USD 80/prototype). With the rapid advance of consumer-grade printers, resin 3-D printing can revolutionize rapid prototyping approaches for microdevices in the near future, facilitating participation in interdisciplinary development of innovative hardware to support germplasm repository development for aquatic species

Development of a Single-Piece Sperm Counting Chamber (SSCC) for Aquatic Species

Accurate determination of sperm concentration in aquatic species is important for assisted reproduction and cryopreservation, yet is challenging as current counting methods are costly or not suitable for many species. The goal of this work was to develop a simple (single-piece and single-layer photolithography) sperm counting chamber (SSCC) for aquatic species. Goldfish (Carassius auratus) and zebrafish (Danio rerio) sperm were used for evaluation in the device, which was created with soft lithography. Four designs with different geometries were evaluated for counting accuracy. Open-corner and open-midpoint designs were the most accurate with no significant differences (P > 0.05) for most of the target sperm concentrations (0.5–1.0 × 108 cells/mL). The open-corner design was not significantly different from the Makler® counting chamber intended for human sperm cells (P = 0.6) but was significantly different from a hemocytometer (P < 0.001) intended for other cell sizes. Material cost of device production was USD 16 per unit, including photolithography supplies, glass slide and coverslip, and polydimethylsiloxane. The cost can be reduced to USD 2 per unit with repeated wafer casts. This device could be further refined for resin 3-D printing and sharing via open-hardware approaches and modified to best suit species specific applications

Machine-learning-assisted spontaneous Raman spectroscopy classification and feature extraction for the diagnosis of human laryngeal cancer

Germplasm repositories can benefit sustainable aquaculture by supporting genetic improvement, assisted reproduction, and management of valuable genetic resources. Lack of reliable quality management tools has impeded repository development in the past several decades. Microfabricated open-hardware devices have emerged as a new approach to assist repository development by providing standardized quality assessment capabilities to enable routine quality control. However, prototyping of microfabricated devices (microdevices) traditionally relies on photolithography techniques that are costly, time intensive, and accessible only through specialized engineering laboratories. Although resin 3-D printing has been introduced into the microfabrication domain, existing publications focus on customized or high-cost (\u3ethousands of USD) printers. The goal of this report was to identify and call attention to the emerging opportunities to support innovation in microfabrication by use of low-cost

Attenuating Fibrotic Markers of Patient-Derived Dermal Fibroblasts by Thiolated Lignin Composites

We report the use of phenolic functional groups of lignosulfonate to impart antioxidant properties and the cell binding domains of gelatin to enhance cell adhesion for poly(ethylene glycol) (PEG)-based scaffolds. Chemoselective thiol-ene chemistry was utilized to form composites with thiolated lignosulfonate (TLS) and methacrylated fish gelatin (fGelMA). Antioxidant properties of TLS were not altered after thiolation and the levels of antioxidation were comparable to those of -ascorbic acid. PEG-fGelMA-TLS composites significantly reduced the difference in , , , and genes between high-scarring and low-scarring hdFBs, providing the potential utility of TLS to attenuate fibrotic responses

Development of a Single-Piece Sperm Counting Chamber (SSCC) for Aquatic Species

Accurate determination of sperm concentration in aquatic species is important for assisted reproduction and cryopreservation, yet is challenging as current counting methods are costly or not suitable for many species. The goal of this work was to develop a simple (single-piece and single-layer photolithography) sperm counting chamber (SSCC) for aquatic species. Goldfish ( and zebrafish () sperm were used for evaluation in the device, which was created with soft lithography. Four designs with different geometries were evaluated for counting accuracy. Open-corner and open-midpoint designs were the most accurate with no significant differences ( \u3e 0.05) for most of the target sperm concentrations (0.5-1.0 × 10 cells/mL). The open-corner design was not significantly different from the Makler counting chamber intended for human sperm cells ( = 0.6) but was significantly different from a hemocytometer ( \u3c 0.001) intended for other cell sizes. Material cost of device production was USD 16 per unit, including photolithography supplies, glass slide and coverslip, and polydimethylsiloxane. The cost can be reduced to USD 2 per unit with repeated wafer casts. This device could be further refined for resin 3-D printing and sharing via open-hardware approaches and modified to best suit species specific applications