Publication: J Appl Toxicol. 2021 Jan 8. doi: 10.1002/jat.4136. Epub ahead of print. PMID: 33417269.

Abstract: The use of synthetic materials for biomedical applications is ever expanding. One of the major requirements for these materials is biocompatibility, which includes prevention of immune system responses. Due to the inherent complexity of their structural composition, the polyurethane (PU) family of polymers is being used in a variety of medical applications, from soft and hard tissue scaffolds to intricate coatings on implantable devices. Herein, we investigated whether two polymer materials, D3 and D7, induced an immune response, measured by their effects on a dendritic cell (DC) line, JAWS II. Using a lactate dehydrogenase cytotoxicity assay and Annexin V/PI staining, we found that the PU materials did not induce cytotoxicity in DC cells. Using confocal microscopy, we also showed that the materials did not induce activation or maturation, as compared to positive controls. This was confirmed by looking at various markers, CD80, CD86, MHC class I, and MHC class II, via flow cytometry. Overall, the results indicated that the investigated PU films are biocompatible in terms of immunotoxicology and immunogenicity and show great promise for use in regenerative medicine.

The post Dendritic cell biocompatibility of ether-based urethane films appeared first on Center for Integrative Nanotechnology Sciences.

Publication: PLoS One. 2020;15(5):e0232670. Published 2020 May 18. doi:10.1371/journal.pone.0232670

Abstract: Complex skin wounds have always been a significant health and economic problem worldwide due to their elusive and sometimes poor or non-healing conditions. If not well-treated,
such wounds may lead to amputation, infections, cancer, or even death. Thus, there is a need to efficiently generate multifunctional skin grafts that address a wide range of skin conditions, including non-healing wounds, and enable the regeneration of new skin tissue. Here, we propose studying pristine graphene and two of its oxygen-functionalized derivatives—high and low-oxygen graphene films—as potential substrates for skin cell proliferation and differentiation. Using BJ cells (human foreskin-derived fibroblasts) to represent basic skin cells, we show that the changes in surface properties of pristine graphene due to oxygen functionalization do not seem to statistically impact the normal proliferation and maturation of skin cells. Our results indicate that the pristine and oxidized graphenes presented relatively low cytotoxicity to BJ fibroblasts and, in fact, support their growth and bioactivity. Therefore, these graphene films could potentially be integrated into more complex skin regenerative systems to support skin regeneration. Because graphene’s surface can be relatively easily functionalized with various chemical groups, this finding presents a major opportunity for the development of various composite materials that can act as active components in regenerative applications such as skin regeneration.

The post Graphene-based 2D constructs for enhanced fibroblast support appeared first on Center for Integrative Nanotechnology Sciences.

Publication: ACS Omega 2020, Publication Date: January 21, 2020,

Abstract: A conducting polymer of lignosulfonic acid-grafted, polyaniline-doped camphorsulfonic acid (LS-PANI-CSA), created via a low-temperature solution process, has been explored as an efficient hole-transport layer (HTL) for inverted single cation–anion CH₃NH₃PbI₃ perovskite solar cells. The performance of the solar cell was optimized in this study by tuning the morphology and work function of LS-PANI-CSA films using dimethylsulfoxide (DMSO) as a solvent in treatment. Results showed that DMSO washing enhanced the electronic properties of the LS-PANI-CSA film and increased its hydrophobicity, which is very important for perovskite growth. The perovskite active layer deposited onto the DMSO-treated LS-PANI-CSA layer had higher crystallinity with large grain sizes (>5 μm), more uniform and complete surface coverage, and very low pinhole density and PbI₂ residues compared to untreated LS-PANI-CSA. These enhancements result in higher device performance and stability. Using DMSO-treated LS-PANI-CSA as an HTL at 15 nm of thickness, a maximum 10.8% power conversion efficiency was obtained in ITO/LS-PANI-CSA/MAPbI₃/PCBM/BCP/Ag inverted-device configurations. This was a significant improvement compared to 5.18% for devices based on untreated LS-PANI-CSA and a slight improvement over PEDOT:PSS-based devices with 9.48%. Furthermore, the perovskite based on treated LS-PANI-CSA showed the higher stability compared to both untreated LS-PANI-CSA and PEDOT:PSS HTL-based devices.

The post Optimizing Lignosulfonic Acid-Grafted Polyaniline as a Hole-Transport Layer for Inverted CH3NH3PbI3 Perovskite Solar Cells appeared first on Center for Integrative Nanotechnology Sciences.

Publication: npj Clean Water (2019) 2:10; https://doi.org/10.1038/s41545-019-0034-1

Abstract:

Methods for the efficient and affordable remediation of oil spills and chemical leaks are crucially needed in today’s environment. In this study, we have developed a simple, magnetic, porous material based on polydimethylsiloxane (PDMS) and steel wool (SW) that can fulfill these needs. The PDMS-SW presented here is superhydrophobic, superoleophilic, and capable of absorbing and separating oils and organic solvents from water. The material is mechanically and chemically stable, even in salty environments, and can be magnetically guided. It exhibits good selectivity, recyclability, and sorption capacity, and can quickly and continuously absorb and remove large amounts of oils and organic solutions from stationary and turbulent water. In addition, PDMS-SW’s
inherently high porosity enables direct, gravity-driven oil-water separation with permeate flux as high as ~32,000 L/m2·h and separation efficiency over 99%. The solution immersion process used to prepare the material is easily scalable and requires only a single step. Thus, with its demonstrated combination of affordability, efficiency, and ease of use, PDMS-SW has the potential to meet the demands of large-area oil and chemical clean-ups.

The post One-step synthesis of a steel-polymer wool for oil-water separation and absorption appeared first on Center for Integrative Nanotechnology Sciences.

Publication: Scientific Reports, Volume 9, Article 5650, pp. 1-13, 2019

Abstract: Supercapacitors are beneficial as energy storage devices and can obtain high capacitance values greater than conventional capacitors and high power densities compared to batteries. However, in order to improve upon the overall cost, energy density, and charge-discharge rates, the electrode material of supercapacitors needs to be fine-tuned with an inexpensive, high conducting source. We prepared a Co(III) complex and polypyrrole (PPy) composite thin films (CoN₄–PPy) that was electrochemically deposited on the surface of a glassy carbon working electrode. Cyclic voltammetry studies indicate the superior performance of CoN₄-PPy in charge storage in acidic electrolyte compared to alkaline and organic solutions. The CoN₄-PPy material generated the highest amount of specific capacitance (up to 721.9 F/g) followed by Co salt and PPy (Co-PPy) material and PPy alone. Cyclic performance studies showed the excellent electrochemical stability of the CoN₄-PPy film in the acidic medium. Simply electrochemically depositing an inexpensive Co(III) complex with a high electrically conducting polymer of PPy delivered a superior electrode material for supercapacitor applications. Therefore, the results indicate that novel thin films derived from Co(III) metal complex and PPy can store a large amount of energy and maintain high stability over many cycles, revealing its excellent potential in supercapacitor devices.

The post Simultaneous Electrochemical Deposition of Cobalt Complex and Poly(pyrrole) Thin Films for Supercapacitor Electrodes appeared first on Center for Integrative Nanotechnology Sciences.

Publication: AIP Conference Proceedings 2083, 030006 (2019);

Abstract:

Porous composite membranes with carbon nanofibers were successfully developed and were shown to show controlled wetting characteristics ranging from superhydrophilic all the way to superhydrophobic. The tunability of the surface morphology and the wetting properties was accomplished by adjusting the CNF characteristics post-processing. First, carbon nanofibers (CNF) with 150 nm dia., and length ∼100 µm were functionalized by a solution process method. They were then dispersed by sonication in deionized water. The dispersion was then vacuum-filtered in the membrane. Second, CNF-based composite films were obtained from dispersing as-received CNF in different solvent systems using sonication processing, then filtered into a membrane architecture separately. The optimum film obtained was found to be a CNF-trifluorotoluene composite. The former CNF-based film displays superhydrophilic wetting characteristics, with a contact angle of ∼0°. The latter coating shows superhydrophobic behavior with a contact angle of as high as 154° and negligible hysteresis.

The post Multiscale composite membrane with carbon nanofibers with tunable characteristics from superhydrophilic to superhydrophobic appeared first on Center for Integrative Nanotechnology Sciences.

Publication: TechConnect Briefs, Volume: 1, Advanced Materials: TechConnect Briefs 2018, Pages: 248 – 251

Abstract:

Due to their outstanding corrosion resistance, wear resistance, thermal stability, and chemical stability, polyvinylidene fluoride (PVDF) membranes are extensively used for membrane distillation, membrane contactor, oil/water separation, and wastewater treatment. Modifying a PVDF membrane with a superhydrophobic nano-coating of polytetrafluoroethylene (PTFE) has been shown to enhance the membrane’s self-cleaning ability, making it even more appealing for these applications. In this work, we used pulsed laser deposition (PLD) to coat PVDF substrates with PTFE thin films at room temperature. To study the effect of the thickness and morphology of the PTFE films on PVDF, the PTFE was deposited at different deposition times (15, 30, 45, 60, and 90 min). SEM analysis showed that PTFE particulates grew uniformly on the PVDF membrane surface, forming a rough and uniform film. Surface roughness was analyzed by atomic force microscopy, which revealed that roughness increased as deposition time increased up to 45 minutes. The highest water contact angle, 155˚ with negligible contact angle hysteresis, was observed for the sample with 45-minute deposition time. The elemental and chemical analysis, performed using x-ray photoelectron spectroscopy, showed the peak intensity of the coated samples’ C-C bond to be stronger than that of the uncoated PTFE target samples. In summary, this study produced a superhydrophobic PVDF membrane with outstanding self-cleaning properties using a convenient one-step technique without a wetting process.

The post Fabrication of superhydrophobic PVDF membranes with PTFE nano-film surface coatings appeared first on Center for Integrative Nanotechnology Sciences.

Publication: RSC Advances, Issue 5

Abstract:

Functionalized graphene (fGn) has been used to deliver the low toxicity plant product, gambogic acid (GA), to cervical, ovarian, and prostate cancer cells, and the relative cytotoxicity of this complex when compared to delivery of drug alone has been evaluated. In this study, we analyzed the characteristics of the GA + fGn complex, including pH-sensitive release of the drug from the nanomaterial. We then compared the in vitro effects of GA and GA + fGn on the growth inhibition and apoptosis in the above three cancer cell types. We found that GA, when delivered as a GA/fGn complex was more effective at inhibiting cell proliferation, initiating cell cycle arrest and inducing apoptosis in HeLa, NCI/ADR-RES, and PC-3 cancer cell lines compared to delivery of drug alone. Overall, our results indicate that this novel GA/fGn nanocomplex has the ability to inhibit proliferation and induce apoptosis in several different organ-derived cancer cells, and could have potential as a new drug delivery strategy in cancer chemotherapy.

The post Nanodelivery of Gambogic Acid by Functionalized Graphene Enhances Inhibition of Cell Proliferation and Induces G0/G1 Cell Cycle Arrest in Cervical, Ovarian, and Prostate Cancer Cells appeared first on Center for Integrative Nanotechnology Sciences.

Publication: Electrochimica Acta, Volume 139

Abstract:

The post The Study of Adenine and Guanine Electrochemical Oxidation Using Electrodes Modified with Graphene-platinum Nanoparticles Composites appeared first on Center for Integrative Nanotechnology Sciences.

Publication: Nanotechnology, 25

Abstract:

Multidimensional scaffolds are considered to be ideal candidates for regenerative medicine and tissue engineering based on their potential to provide an excellent microenvironment and direct the fate of the cultured cells. More recently, the use of stem cells in medicine has opened a new technological opportunity for controlled tissue formation. However, the mechanism through which the substrate directs the differentiation of stem cells is still rather unclear. Data concerning its specific surface chemistry, topology, and its signaling ability need to be further understood and analyzed. In our study, atomic force microscopy was used to study the stiffness, roughness, and topology of the collagen (Coll) and metallized collagen (MC) substrates, proposed as an excellent substrate for regenerative medicine. The importance of signaling molecules was studied by constructing a new hybrid signaling substrate that contains both collagen and laminin extracellular matrix (ECM) proteins. The cellular response—such as attachment capability, proliferation and cardiac and neuronal phenotype expression on the metallized and non-metallized hybrid substrates (collagen + laminin)—was studied using MTT viability assay and immunohistochemistry studies. Our findings indicate that such hybrid materials could play an important role in the regeneration of complex tissues.

The post Multistructural-Biomimetic Substrates for Controlled Cellular Differentiation appeared first on Center for Integrative Nanotechnology Sciences.