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516 results on '"Kipper, Matt J."'

19. Anomalous protein kinetics on low-fouling surfaces

Author

Hedayati, Mohammadhasan, Kipper, Matt J., and Krapf, Diego

Subjects
Physics - Chemical Physics, Condensed Matter - Statistical Mechanics
Abstract

In this work, protein-surface interactions were probed in terms of adsorption and desorption of a model protein, bovine serum albumin, on a low-fouling surface with single-molecule localization microscopy. Single-molecule experiments enable precise determination of both adsorption and desorption rates. Strikingly the experimental data show anomalous desorption kinetics, evident as a surface dwell time that exhibits a power-law distribution, i.e. a heavy-tailed rather than the expected exponential distribution. As a direct consequence of this heavy-tailed distribution, the average desorption rate depends upon the time scale of the experiment and the protein surface concentration does not reach equilibrium. Further analysis reveals that the observed anomalous desorption emerges due to the reversible formation of a small fraction of soluble protein multimers (small oligomers), such that each one desorbs from the surface with a different rate. The overall kinetics can be described by a series of elementary reactions, yielding simple scaling relations that predict experimental observations. This work reveals a mechanistic origin for anomalous desorption kinetics that can be employed to interpret observations where low-protein fouling surfaces eventually foul when in long-term contact with protein solutions. The work also provides new insights that can be used to define design principles for non-fouling surfaces and to predict their performance.

Published
2019
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20. AIChE Virtual Communities of Practice-Supporting Faculty during the COVID-19 Pandemic

Author

Liberatore, Matthew W., Lepek, Daniel, Ford, Laura P., Carter, Tracy, Pascal, Jennifer, Lamm, Monica, Luks, Christi Patton, Silverstein, David L., Ford Versypt, Ashlee N., Velegol, Stephanie Butler, Vogel, Troy, Raikar, Neha, Kipper, Matt J., and West, Christy Wheeler

Abstract

In response to the COVID-19 pandemic, chemical engineering departments from around the world shifted their course offerings from in-person to online almost instantaneously. The AIChE Education Division immediately responded to this educational shift by developing five Virtual Communities of Practice (VCPs) that allowed faculty to share experiences and best practices as well as provide a network for emotional support. Community creation, methods and materials shared, and surveys related to the impact of this initiative will be discussed.

Published
2022
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32. Acid and Alkali-Resistant Electrospun Porous Silica/Carbon Nanotubes Nanofibrous Membrane for Oil/Water Separation.

Author

Xing, Wei, Wang, Yanxin, Mao, Xinhui, Gao, Zhiyuan, Wang, Zilong, Kipper, Matt J., Huang, Linjun, and Tang, Jianguo

Abstract

Managing oily wastewater remains a challenging issue in terms of technology. The technology of membrane separation can provide both high separation efficiency and low operating cost, so the exploitation of highly effective oil/water separation membranes has become a research hotspot. In the present work, we prepared porous silica (SiO2)/carbon nanotubes (CNTs) nanofibrous membrane (PSCM) by comixing hydrophilic CNTs and carbon nanospheres (CNSs) with SiO2 precursor liquid, followed by the electrospinning method. The addition of CNTs has enhanced the roughness of the nanofibrous membrane and improved the wettability, making the membrane superhydrophilic. Meanwhile, the strong electrostatic attraction between SiO2 and CNTs makes the bond between them stronger, which is favorable for withstanding the osmotic pressure from the liquid. The presence of PSCM micro/nanoporous structure creates an infiltration channel for the liquid, and the porous structure gives it excellent porosity, which greatly improves the performance of oil/water separation. The membrane has high separation performance for oil/water mixtures in gravity-based feeding devices with a high separation flux of up to 8340 L m–2 h–1 and separation efficiency of up to 99.5%. In addition, we found that PSCM has good resistance to oil pollution and acid and alkali resistances through testing. It still has a flux of 6231 L m–2 h–1 and 5512 L m–2 h–1 under strong acid and alkali conditions, respectively, and performs well in the cyclic separation test under strong acid and alkali conditions. This work provides perspectives on oily wastewater and water purification remediation. [ABSTRACT FROM AUTHOR]

Published
2024
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33. Covalent Grafting of Tanfloc on Titania Nanotube Arrays: An Approach to Mitigate Bacterial Adhesion and Improve the Antibacterial Efficacy of Titanium Implants.

Author

Singh, Ramesh, Madruga, Liszt Y. C., Savargaonkar, Aniruddha, Martins, Alessandro F., Kipper, Matt J., and Popat, Ketul C.

Subjects
BACTERIAL cell membranes, BACTERIAL cell walls, TREATMENT effectiveness, PHOTOELECTRON spectroscopy, BACTERIAL adhesion
Abstract

Implanted medical devices often face the challenge of infections, which can compromise their successful integration and use. To address this issue, this study demonstrates the covalent grafting of a tannin‐based antimicrobial biopolymer tanfloc (TAN) onto the titania nanotube arrays (TiNTs) surface to enhance antibacterial properties. Due to its polyphenolic and ionic structural configuration, tanfloc possesses unique properties that enable it to interact with and disrupt bacterial cell walls and membranes. Combining the topographical effect of TiNTs with the inherent antibacterial properties of tanfloc, this approach aims to mitigate bacterial threats on medical implants effectively. The successful attachment of tanfloc on TiNTs is confirmed through X‐ray photoelectron spectroscopy (XPS) and Fourier‐transform infrared spectroscopy (FT‐IR). The antibacterial and antibiofilm efficacy of the tanfloc‐functionalized TiNTs is evaluated against Staphylococcus aureus (Gram‐positive) and Pseudomonas aeruginosa (Gram‐negative) bacteria. The findings suggest that the covalent conjugation of tanfloc onto TiNTs is a promising approach to improve the infection resistance of titanium‐based medical implants, with potential applications in orthopedic, dental, and other biomedical device areas. [ABSTRACT FROM AUTHOR]

Published
2024
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34. Electrospun Fibers of Ecovio ® Polymer Blends with Antimicrobial Tea Tree Essential Oil: Enhanced Chemical and Biological Properties.

Author

de Souza, Bianca Z., Facchi, Débora P., Facchi, Suelen P., Teodoro, Carlos F., de Almeida, Débora A., Popat, Ketul C., Kipper, Matt J., Bonafé, Elton G., and Martins, Alessandro F.

Subjects
TEA tree oil, ATTENUATED total reflectance, X-ray photoelectron spectroscopy, DIFFERENTIAL scanning calorimetry, BACTERIAL adhesion, POLYMER blends
Abstract

This study presents the development of fibers with favorable properties for biodegradable wound dressings made from the Ecovio® (EC) polymer blend, composed of poly(lactic acid) (PLA) and poly(butylene adipate-co-terephthalate) (PBAT), incorporated with tea tree essential oil (TTE). TTE presented antimicrobial activity against Pseudomonas aeruginosa and Staphylococcus aureus, achieving minimal inhibitory concentrations (MIC) of 15 and 7.5 mg/mL, respectively. The TTE was mixed with EC in a binary chloroform and formic acid (85/15 v/v) mixture. The EC/TTE fibers were characterized by differential scanning calorimetry (DSC), Fourier-transform infrared with attenuated total reflectance (FTIR-ATR), and X-ray photoelectron spectroscopy (XPS), confirming the TTE in the fibers. The tests showed that TTE (0.5, 1.0, or 1.5 mL) improved the polymer blend's electrospinnability, leading to bead-free, homogenous, and smaller fiber diameters. TTE (1.5 mL or 75 w% concerning the EC) leads to homogeneous fibers with an average diameter of 278 ± 59 nm. TTE (75 w%) increased the wettability of the EC fibers from 120 ± 2° to 69 ± 1°. Preliminary bacterial adhesion and proliferation assays demonstrated that the EC/TTE fibers have anti-adhesive activity and demonstrate greater toxicity, which seems more toxic against P. aeruginosa than S. aureus after 24 h of incubation. Fluorescence and coagulation kinetics tests performed with human blood indicated that the EC/TTE fibers accelerate blood coagulation. The EC/TTE fibers exhibit promising chemical and biological properties (in vitro) for developing wound dressings. [ABSTRACT FROM AUTHOR]

Published
2024
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35. Smart Cancer-Targeting and Super-Sensitive Sensing of Eu 3+ /Tb 3+ -Induced Hyaluronan Characteristic Nano-Micelles with Effective Drug Loading and Release.

Author

Bi, Yupeng, Li, Longlong, Liu, Jin, Wang, Yao, Wang, Boying, Wang, Yanxin, Snow, Christopher D., Li, Jun, Kipper, Matt J., Belfiore, Laurence A., and Tang, Jianguo

Subjects
MELANOMA, TREATMENT effectiveness, ANTINEOPLASTIC agents, CYTOTOXINS, DRUG efficacy, DRUG carriers, DRUG delivery systems
Abstract

To avoid the critical problems of effective drugs not being carried to their targeted cancers and their quantity and location not being sensed in situ, this work presents a completely new innovative strategy to achieve both smart cancer targeting (SCT) and super-sensitive sensing (SSS), where one drug carrier works for effective drug loading and release. Herein, malignant melanoma treatment is used as an example of reliable detection and effective therapy. We report two characteristic dumbbell-like nano-micelles and spherical-like nano-micelles of hyaluronan induced by the Eu3+/Tb3+ complexes for effective drug loading and release, respectively. These special Eu3+/Tb3+-loaded nano-micelles (marked as ENM and TNM) have strong and sharp red/green luminescence that can sensitively detect the malignant melanoma drug dacarbazine through changes in fluorescence intensity. Cytotoxicity experiments confirmed that both ENM and TNM are not toxic to normal cells at very high concentrations of 4 mM. However, when loaded with cancer drugs (D-ENM and D-ENM), they both killed cancer cells with more than 40% efficacy at this concentration. The in vivo experiments confirmed that D-ENM and D-TNM can effectively target cancer cells in tissue and effectively impede cancer growth. The detection limits of ENM and TNM in sensing cancer drugs can reach 0.456 μg/mL and 0.139 μg/mL, respectively. Therefore, the reported Eu3+/Tb3+-induced hyaluronan nano-micelles (ENM and TNM) are distinguished carriers of this cancer drug and excellent in situ sensors, and they have highly therapeutic effects with extremely low toxicity to normal cells. [ABSTRACT FROM AUTHOR]

Published
2024
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