UMBC Chemical, Biochemical & Environmental Engineering Department

Permanent URI for this collectionhttp://hdl.handle.net/11603/49

Faculty in our department focus their research in nine core areas encompassing biological, environmental, and educational research. Our department offers an undergraduate course of study leading to a B.S. in Chemical Engineering through three tracks of study: (i) Traditional Track, (ii) Biotechnology and Bioengineering Track and (iii) Environmental Engineering and Sustainability track. We also offer both M.S. and Ph.D. degrees through two different graduate programs. Details can be found on our website: http://www.umbc.edu/cbe

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Delivery of Tempol from Polyurethane Nanocapsules to Address Oxidative Stress Post-Injury
(ACS, 2025-02-08) Ale, Temitope; Ale, Tolulope; Baker, Kimberly J.; Zuniga, Kameel M.; Hutcheson, Jack; Lavik, Erin
Traumatic brain injuries (TBIs) result in significant morbidity and mortality due to the cascade of secondary injuries involving oxidative stress and neuroinflammation. The development of effective therapeutic strategies to mitigate these effects is critical. This study explores the fabrication and characterization of polyurethane nanocapsules for the sustained delivery of Tempol, a potent antioxidant. The nanocapsules were designed to extend the release of Tempol over a 30-day period, addressing the prolonged oxidative stress observed post-TBI. Tempol-loaded polyurethane nanocapsules were synthesized using interfacial polymerization and nanoemulsion techniques. Two generations of nanocapsules were produced, differing in Tempol loading and PEGylation levels. The first generation, with lower Tempol loading, exhibited an average size of 159.8 ± 12.61 nm and a Z-average diameter of 771.9 ± 87.95 nm. The second generation, with higher Tempol loading, showed an average size of 141.4 ± 6.13 nm and a Z-average diameter of 560.7 ± 171.1 nm. The zeta potentials were ?18.9 ± 5.02 mV and ?11.9 ± 3.54 mV for the first and second generations, respectively. Both generations demonstrated the presence of urethane linkages, confirmed by Fourier Transform Infrared Spectroscopy (FTIR). Loading studies revealed Tempol concentrations of 61.94 ± 3.04 ?g/mg for the first generation and 77.61 ± 3.04 ?g/mg for the second generation nanocapsules. Release profiles indicated an initial burst followed by a sustained, nearly linear release over 30 days. The higher PEGylation in the second generation nanocapsules is advantageous for intravenous administration, potentially enhancing their therapeutic efficacy in TBI treatment. This study demonstrates the feasibility of using polyurethane nanocapsules for the prolonged delivery of Tempol, offering a promising approach to manage oxidative stress and improve outcomes in TBI patients. Future work will include testing these nanocapsules in vivo to determine their potential at modulating recovery from TBI.
Bioconjugates for Cancer Prevention: Opportunities for Impact
(ACS, 2024-08-21) Lavik, Erin; Minasian, Lori
Cancer prevention encompasses both screening strategies to find cancers early when they are likely to be most treatable and prevention and interception strategies to reduce the risk of developing cancers. Bioconjugates, here defined broadly as materials and molecules that have synthetic and biological components, have roles to play across the cancer-prevention spectrum. In particular, bioconjugates may be developed as affordable, accessible, and effective screening strategies or as novel vaccines and drugs to reduce one’s risk of developing cancers. Developmental programs are available for taking novel technologies and evaluating them for clinical use in cancer screening and prevention. While a variety of different challenges exist in implementing cancer-prevention interventions, a thoughtful approach to bioconjugates could improve the delivery and acceptability of the interventions.
Application of the Rd/w framework to assess Donnan dialysis performance
(Elsevier, 2023-12-01) Chen, Hui; Souizi, Sahar; Stewart, Kaylyn; Blaney, Lee
Donnan dialysis exploits electrochemical potential gradients across ion-exchange membranes to separate ions between feed and draw solutions. This technique has been applied for treatment and recovery of chemicals in water and wastewater. Previous studies have arbitrarily selected the draw solution chemistry, making it difficult to fairly compare experimental outcomes. A universal framework is needed to standardize design and interpretation of Donnan dialysis systems. We calculated the Rd/w parameter, which is related to the draw ion concentrations in the feed and draw solutions at Donnan equilibrium, for previous studies. Rd/w values were used to determine theoretical recoveries and compare them to experimental outcomes. Of the literature data, 57% matched the theoretical recovery, 37% underperformed due to operating time constraints or transport limitations, and 6% outperformed Donnan equilibrium due to use of integrated processes. Ultimately, this work highlights the benefits of the Rd/w framework for standardizing interpretation of Donnan dialysis systems.
Using multilinear regressions developed from excitation-emission matrices to estimate the wastewater content in urban streams impacted by sanitary sewer leaks and overflows
(Elsevier, 2024-01-01) Batista-Andrade, Jahir Antonio; Iglesias Vega, Diego; McClain, Anna; Blaney, Lee
Failing sewer infrastructure introduces unknown quantities of raw wastewater into urban streams, raising human and ecological health concerns. To address this problem, we developed multilinear regressions that relate fluorescent dissolved organic matter to wastewater content. The models were constructed with the area-normalized regional volumes of excitation-emission matrices measured for mixtures of deionized water, surface water from a wastewater-impacted stream, wastewater from a sanitary sewer adjacent to the stream, and Suwannee River natural organic matter. The best performing multilinear regression had a standard error of 0.55 % wastewater. A matrix-matched calibration was used to internally validate the approach and confirm the wastewater content of select samples. The multilinear model was externally validated through (i) comparison to concentrations of contaminants of emerging concern in surface water and wastewater and (ii) extension to samples from previous campaigns that employed alternative wastewater indicators. Using the validated model, we estimated an average wastewater content of 2.4 ± 4.0 % in 165 samples collected from 14 locations in the Gwynns Falls watershed (USA) between April 2019 and April 2023. The maximum wastewater content was 35 % at a site where sanitary sewer leaks and overflows have been previously documented. The reported approach represents a cost-effective and scalable technique to estimate wastewater content in urban streams through analysis of fluorescent dissolved organic matter.
The role of Fe(IV) in the zero-valent iron biochar activated persulfate system for treatment of contaminants of emerging concern
(Elsevier, 2024-05-01) Gong, Wenwen; He, Dandan; Wang, Xiao; Yan, Yuting; Dionysiou, Dionysios D.; Blaney, Lee; Peng, Guilong
In this paper, Fe(IV) was analyzed in the zero-valent iron biochar (ZVI-BC) activated persulfate (PS) process with methyl phenyl sulfoxide (PMSO) as the probe compound. Without a reaction terminator, PMSO degradation continued during the sample holding time, resulting in significant errors in the kinetics analysis. When 1 mM NaNO₂, 1 mM NH₂OH, 10 mM Na₂S₂O₃, or 10 mM dimethyl sulfoxide were used as terminators, the concentrations of PMSO and its oxidation product, methyl phenyl sulfone (PMSO₂), were effectively maintained without changes during the sample holding period. Furthermore, the terminators did not interfere with PMSO or PMSO₂ analysis by high performance liquid chromatography. In addition to Fe(IV), free radical (i.e., SO₄^.-, OH, O₂^.-) and nonradical (i.e., ¹O₂) reactive species were also involved in the ZVI-BC/PS system; however, Fe(IV) was the predominant reactive species. Organic contaminants with electron-donating moieties rapidly reacted with Fe(IV), and the relative contribution of Fe(IV) to overall contaminant degradation decreased as the solution pH was increased. Overall, this study provided new insights into the quantitative analysis of Fe(IV) in the ZVI-BC/PS system and its application to treatment of organic contaminants in solutions with variable water quality.
Analysis of the steady-state concentrations of reactive species and their role in contaminant degradation by the iron-biochar/persulfate advanced oxidation process: Comparison of probe compound and quenching agent methods
(Elsevier, 2025-02-19) Meng, Xukun; Peng, Guilong; Yan, Yuting; Wang, Xiao; Zhu, Jiangwei; Belver, Carolina; Gong, Wenwen; Blaney, Lee
Reactive species, including hydroxyl radicals (OH), sulfate radicals (SO₄), singlet oxygen (¹O₂), superoxide radicals (O₂), and Fe(IV), are generated by the iron-biochar activated persulfate (Fe-BC/PS) process. These reactive species can be leveraged for treatment of micropollutants, such as the sulfamethoxazole antibiotic. In this study, the steady-state concentrations and contributions of OH, SO₄, ¹O₂, O₂, and Fe(IV) to sulfamethoxazole degradation were calculated for different operating conditions in the iron-biochar/persulfate (Fe-BC/PS advanced oxidation process. Electron paramagnetic resonance was employed to confirm the production of each reactive species. The nitrobenzene, benzoic acid, furfuryl alcohol, p-chlorobenzoic acid or p-benzoquinone, and phenyl methyl sulfoxide probe compounds were added to experimental solutions in isolation, as mixtures, and at different concentrations to calculate the steady-state concentrations of OH, SO₄, ¹O₂, O₂, and Fe(IV) and determine their contributions to sulfamethoxazole degradation at variable pH conditions. The results not only informed the primary mechanisms of sulfamethoxazole degradation by the Fe-BC/PS system, but also highlighted best practices for the use of probe compounds and quenching agents in persulfate-based advanced oxidation processes. In particular, the initial concentration of the probe compounds should be as low as possible to avoid impacts on target contaminant degradation and misinterpretation of the role of each reactive species. Furthermore, quenching-based approaches to determination of the key reactive species were less consistent than evaluation by probe compounds. The overall outcomes of this work inform sulfamethoxazole treatment by the Fe-BC/PS system and emphasize the need for internal validation of kinetics results using a multi-pronged approach.
Synthetic Generation of Dynamic Omics Data Demonstrates Aspergillus nidulans BrlA Paradoxical Wall Stress Response
(2025-03-03) Zavorskas, Joseph; Edwards, Harley; Huso, Walker; Doan, Alexander G.; Marten, Mark; Harris, Steven; Srivastava, Ranjan
We propose a method to generate additional dynamic omics trajectories which could support pathway analysis methods such as enrichment analysis, genetic programming, and machine learning. Using long short-term memory neural networks, we can effectively predict an organism’s dynamic response to a stimulus based on an initial dataset with relatively few samples. We present both an in silico proof of principle, based on a model that simulates viral propagation, and an in vitro case study, tracking the dynamics of Aspergillus nidulans’ BrlA transcript in response to antifungal agent micafungin. Our silico experiment was conducted using a highly noisy dataset with only 25 replicates. This proof of principle shows that this method can operate on biological datasets, which often have high variance and few replicates. Our in silico validation achieved a maximum R² value of approximately 0.95 on our highly noisy, stochastically simulated data. Our in vitro validation achieves an R² of 0.71. As with any machine learning application, this method will work better with more data; however, both of our applications attain acceptable validation metrics with very few biological replicates. The in vitro experiments also revealed a novel paradoxical dose-response effect: transcriptional upregulation by Aspergillus nidulans BrlA is highest at an intermediate dose of 10 ng/mL and is reduced at both higher and lower concentrations of micafungin.
Reflections from the 2024 Large Language Model (LLM) Hackathon for Applications in Materials Science and Chemistry
(2025-01-03) Zimmermann, Yoel; Bazgir, Adib; Afzal, Zartashia; Agbere, Fariha; Ai, Qianxiang; Alampara, Nawaf; Al-Feghali, Alexander; Ansari, Mehrad; Antypov, Dmytro; Aswad, Amro; Bai, Jiaru; Baibakova, Viktoriia; Biswajeet, Devi Dutta; Bitzek, Erik; Bocarsly, Joshua D.; Borisova, Anna; Bran, Andres M.; Brinson, L. Catherine; Calderon, Marcel Moran; Canalicchio, Alessandro; Chen, Victor; Chiang, Yuan; Circi, Defne; Charmes, Benjamin; Chaudhary, Vikrant; Chen, Zizhang; Chiu, Min-Hsueh; Clymo, Judith; Dabhadkar, Kedar; Daelman, Nathan; Datar, Archit; Jong, Wibe A. de; Evans, Matthew L.; Fard, Maryam Ghazizade; Fisicaro, Giuseppe; Gangan, Abhijeet Sadashiv; George, Janine; Gonzalez, Jose D. Cojal; Götte, Michael; Gupta, Ankur K.; Harb, Hassan; Hong, Pengyu; Ibrahim, Abdelrahman; Ilyas, Ahmed; Imran, Alishba; Ishimwe, Kevin; Issa, Ramsey; Jablonka, Kevin Maik; Jones, Colin; Josephson, Tyler R.; Juhasz, Greg; Kapoor, Sarthak; Kang, Rongda; Khalighinejad, Ghazal; Khan, Sartaaj; Klawohn, Sascha; Kuman, Suneel; Ladines, Alvin Noe; Leang, Sarom; Lederbauer, Magdalena; Sheng-Lun; Liao; Liu, Hao; Liu, Xuefeng; Lo, Stanley; Madireddy, Sandeep; Maharana, Piyush Ranjan; Maheshwari, Shagun; Mahjoubi, Soroush; Márquez, José A.; Mills, Rob; Mohanty, Trupti; Mohr, Bernadette; Moosavi, Seyed Mohamad; Moßhammer, Alexander; Naghdi, Amirhossein D.; Naik, Aakash; Narykov, Oleksandr; Näsström, Hampus; Nguyen, Xuan Vu; Ni, Xinyi; O'Connor, Dana; Olayiwola, Teslim; Ottomano, Federico; Ozhan, Aleyna Beste; Pagel, Sebastian; Parida, Chiku; Park, Jaehee; Patel, Vraj; Patyukova, Elena; Petersen, Martin Hoffmann; Pinto, Luis; Pizarro, José M.; Plessers, Dieter; Pradhan, Tapashree; Pratiush, Utkarsh; Puli, Charishma; Qin, Andrew; Rajabi, Mahyar; Ricci, Francesco; Risch, Elliot; Ríos-García, Martiño; Roy, Aritra; Rug, Tehseen; Sayeed, Hasan M.; Scheidgen, Markus; Schilling-Wilhelmi, Mara; Schloz, Marcel; Schöppach, Fabian; Schumann, Julia; Schwaller, Philippe; Schwarting, Marcus; Sharlin, Samiha; Shen, Kevin; Shi, Jiale; Si, Pradip; D'Souza, Jennifer; Sparks, Taylor; Sudhakar, Suraj; Talirz, Leopold; Tang, Dandan; Taran, Olga; Terboven, Carla; Tropin, Mark; Tsymbal, Anastasiia; Ueltzen, Katharina; Unzueta, Pablo Andres; Vasan, Archit; Vinchurkar, Tirtha; Vo, Trung; Vogel, Gabriel; Völker, Christoph; Weinreich, Jan; Yang, Faradawn; Zaki, Mohd; Zhang, Chi; Zhang, Sylvester; Zhang, Weijie; Zhu, Ruijie; Zhu, Shang; Janssen, Jan; Li, Calvin; Foster, Ian; Blaiszik, Ben
Here, we present the outcomes from the second Large Language Model (LLM) Hackathon for Applications in Materials Science and Chemistry, which engaged participants across global hybrid locations, resulting in 34 team submissions. The submissions spanned seven key application areas and demonstrated the diverse utility of LLMs for applications in (1) molecular and material property prediction; (2) molecular and material design; (3) automation and novel interfaces; (4) scientific communication and education; (5) research data management and automation; (6) hypothesis generation and evaluation; and (7) knowledge extraction and reasoning from scientific literature. Each team submission is presented in a summary table with links to the code and as brief papers in the appendix. Beyond team results, we discuss the hackathon event and its hybrid format, which included physical hubs in Toronto, Montreal, San Francisco, Berlin, Lausanne, and Tokyo, alongside a global online hub to enable local and virtual collaboration. Overall, the event highlighted significant improvements in LLM capabilities since the previous year's hackathon, suggesting continued expansion of LLMs for applications in materials science and chemistry research. These outcomes demonstrate the dual utility of LLMs as both multipurpose models for diverse machine learning tasks and platforms for rapid prototyping custom applications in scientific research.
Anaerobic biodegradation of perfluorooctane sulfonate (PFOS) and microbial community composition in soil amended with a dechlorinating culture and chlorinated solvents
(Elsevier, 2024-07-01) Lorah, Michelle M.; He, Ke; Blaney, Lee; Akob, Denise M.; Harris, Cassandra; Tokranov, Andrea; Hopkins, Zachary; Shedd, Brian P.
Perfluorooctane sulfonate (PFOS), one of the most frequently detected per- and polyfluoroalkyl substances (PFAS) occurring in soil, surface water, and groundwater near sites contaminated with aqueous film-forming foam (AFFF), has proven to be recalcitrant to many destructive remedies, including chemical oxidation. We investigated the potential to utilize microbially mediated reduction (bioreduction) to degrade PFOS and other PFAS through addition of a known dehalogenating culture, WBC-2, to soil obtained from an AFFF-contaminated site. A substantial decrease in total mass of PFOS (soil and water) was observed in microcosms amended with WBC-2 and chlorinated volatile organic compound (cVOC) co-contaminants — 46.4 ± 11.0 % removal of PFOS over the 45-day experiment. In contrast, perfluorooctanoate (PFOA) and 6:2 fluorotelomer sulfonate (6:2 FTS) concentrations did not decrease in the same microcosms. The low or non-detectable concentrations of potential metabolites in full PFAS analyses, including after application of the total oxidizable precursor assay, indicated that defluorination occurred to non-fluorinated compounds or ultrashort-chain PFAS. Nevertheless, additional research on the metabolites and degradation pathways is needed. Population abundances of known dehalorespirers did not change with PFOS removal during the experiment, making their association with PFOS removal unclear. An increased abundance of sulfate reducers in the genus Desulfosporosinus (Firmicutes) and Sulfurospirillum (Campilobacterota) was observed with PFOS removal, most likely linked to initiation of biodegradation by desulfonation. These results have important implications for development of in situ bioremediation methods for PFAS and advancing knowledge of natural attenuation processes.
Probing Electrochemical Strain Generation in Vanadium Oxide Cathodes during Cycling of Aqueous Zinc-Ion Batteries via Imaging Technique
(ACS, 2025-03-16) Marckx, Bret; Maclennan, Hunter; Capraz, Ömer Özgür
Aqueous batteries have received a great deal of attention for grid-scale energy storage applications but suffer from low-capacity retention and utilization. A lack of understanding of chemomechanical instabilities and charge storage mechanisms in cathodes limits the development of advanced aqueous batteries. To shed light on these instabilities, operando techniques are necessary to probe the complex interplay between electrochemistry and mechanics during cycling. Here, we report an operando technique to probe electrochemical strains in cathodes in aqueous electrolytes during battery cycling via optical imaging and digital image correlation. Operando mechanical measurements indicate that the cathode undergoes positive strain generation during discharge and negative generation during charge. Strain derivatives reveal a close correlation between electrochemical and mechanical behaviors, highlighting the connection between electrochemistry and mechanics. This operando imaging technique is broadly applicable and paves the way for a deeper understanding of deformation mechanisms in aqueous, multivalent ion battery materials.
Polyurethane Nanocapsules Incorporating Epigallocatechin Gallate, A Green Tea Extract
(Wiley, 2025-02-26) Ale, Temitope; Ghunney, Nhyira; Pandala, Narendra; Tucker, Budd; McFadden, Kassandra; Hutcheson, Jack; Lavik, Erin
Explosions cause 79% of combat-related injuries, often leading to traumatic brain injury (TBI) and hemorrhage. Epigallocatechin gallate (EGCG), a green tea polyphenol, aids neuroprotection and wound healing. In this work, we sought to investigate the fabrication and characterization of polyurethane nanocapsules encapsulating EGCG, demonstrating controlled, on-demand release, and highlighting their potential for targeted therapeutic delivery in trauma care.
Delivery of Tempol from Polyurethane Nanocapsules to Address Oxidative Stress Post-Injury
(ACS, 2025-02-19) Ale, Temitope; Ale, Tolulope; Baker, Kimberly J.; Zuniga, Kameel M.; Hutcheson, Jack; Lavik, Erin
Traumatic brain injuries (TBIs) result in significant morbidity and mortality due to the cascade of secondary injuries involving oxidative stress and neuroinflammation. The development of effective therapeutic strategies to mitigate these effects is critical. This study explores the fabrication and characterization of polyurethane nanocapsules for the sustained delivery of Tempol, a potent antioxidant. The nanocapsules were designed to extend the release of Tempol over a 30-day period, addressing the prolonged oxidative stress observed post-TBI. Tempol-loaded polyurethane nanocapsules were synthesized using interfacial polymerization and nanoemulsion techniques. Two generations of nanocapsules were produced, differing in Tempol loading and PEGylation levels. The first generation, with lower Tempol loading, exhibited an average size of 159.8 ± 12.61 nm and a Z-average diameter of 771.9 ± 87.95 nm. The second generation, with higher Tempol loading, showed an average size of 141.4 ± 6.13 nm and a Z-average diameter of 560.7 ± 171.1 nm. The zeta potentials were -18.9 ± 5.02 mV and -11.9 ± 3.54 mV for the first and second generations, respectively. Both generations demonstrated the presence of urethane linkages, confirmed by Fourier Transform Infrared Spectroscopy (FTIR). Loading studies revealed Tempol concentrations of 61.94 ± 3.04 μg/mg for the first generation and 77.61 ± 3.04 μg/mg for the second generation nanocapsules. Release profiles indicated an initial burst followed by a sustained, nearly linear release over 30 days. The higher PEGylation in the second generation nanocapsules is advantageous for intravenous administration, potentially enhancing their therapeutic efficacy in TBI treatment. This study demonstrates the feasibility of using polyurethane nanocapsules for the prolonged delivery of Tempol, offering a promising approach to manage oxidative stress and improve outcomes in TBI patients. Future work will include testing these nanocapsules in vivo to determine their potential at modulating recovery from TBI.
Polyurethane Nanocapsules Incorporating Epigallocatechin Gallate, A Green Tea Extract
(Wiley, 2025-02-26) Ale, Temitope; Ghunney, Nhyira; Pandala, Narendra; Tucker, Budd; McFadden, Kassandra; Hutcheson, Jack; Lavik, Erin
Explosions cause 79% of combat-related injuries, often leading to traumatic brain injury (TBI) and hemorrhage. Epigallocatechin gallate (EGCG), a green tea polyphenol, aids neuroprotection and wound healing. In this work, we sought to investigate the fabrication and characterization of polyurethane nanocapsules encapsulating EGCG, demonstrating controlled, on-demand release, and highlighting their potential for targeted therapeutic delivery in trauma care.
Recent Advances in Wearable Sweat Sensor Development
(Wiley, 2025) Zhang, Tao; Kabandana, Giraso Keza Monia; Terrell, John A.; Chen, Hui; Chen, Chengpeng
Wearable sweat sensors for detecting biochemical markers have emerged as a transformative research area, with the potential to revolutionize disease diagnosis and human health monitoring. Since 2016, a substantial body of pioneering and translational work on sweat biochemical sensors has been reported. This review aims to provide a comprehensive summary of the current state-of-the-art in the field, offering insights and perspectives on future developments. The focus is on wearable microfluidic platforms for sweat collection and delivery and the analytical chemistry applicable to wearable devices. Various microfluidic technologies, including those based on synthetic polymers, paper, textiles, and hydrogels, are discussed alongside diverse detection methods such as electrochemistry and colorimetry. Both the advantages and current limitations of these technologies are critically examined. The review concludes with our perspectives on the future of wearable sweat sensors, with the goal of inspiring new ideas, innovations, and technical advancements to further the development and practical application of these devices in promoting human health.
Bridging the Gap: At-Home Experiments Connecting Theory and Practice in Chemical Engineering Education
(ASEE, 2024) Das, Gautom K.
The 2022 report by the National Academies of Sciences, Engineering, and Medicine urged a greater focus on experimental learning to bridge core course silos. ABET also requires students to design and conduct experiments, analyze data, and draw conclusions by graduation. However, the packed engineering curriculum challenges additional hands-on lab courses. To address this, we explored an idea to extend learning beyond traditional settings. Inspired by the American Chemical Society's guidelines, we aimed to study at-home experiments for connecting experiments to theories and investigated if students could independently design experiments at home, aligning with the senior chemical engineering laboratory course's objectives. Students spent four weeks conducting at-home experiments and self-evaluated their learning outcomes. Results indicated positive attitudes and their enthusiastic time investment. The at-home projects enhanced learning, fostered critical thinking, and aligned with evolving engineering education priorities. In future iterations, we plan to allocate more time and extend project timelines for greater learning experience.
Climatology of aerosol pH and its controlling factors at the Melpitz continental background site in central Europe
(EGU, 2025-02-10) Pratap, Vikram; Hennigan, Christopher; Stieger, Bastian; Tilgner, Andreas; Poulain, Laurent; van Pinxteren, Dominik; Spindler, Gerald; Herrmann, Hartmut
Aerosol acidity has importance for the chemical and physical properties of atmospheric aerosol particles and for many processes that affect their transformations and fate. Here, we characterize trends in aerosol pH and its controlling factors over the period of 2010 – 2019 at the Melpitz research station in eastern Germany, a continental background site in central Europe. Aerosol liquid water content (ALWC) decreased by 50 % during the analyzed time period in response to decreasing sulfate and nitrate. Aerosol pH exhibited an increase of 0.06 units per year, a trend that was distinct from other regions. Seasonal analysis showed strong variability in factors controlling aerosol pH.
Microdroplet-enabled high-throughput cultivation of vaginal bacteria using cervicovaginal fluids
(2023-09-26) Jackman, Corine; Tan, James Y.; Lin, Xiaoxia Nina
The human vaginal microbiome (HVM) is closely associated with the health of the host. In particular, bacterial vaginosis, a condition where vaginal lactobacilli are reduced dramatically by an overgrowth of various other bacteria, has been linked to increased risk of sexually transmitted infectious diseases, including HIV, and preterm birth. Recent culture-independent studies leveraging next-generation sequencing technology have revealed that the HVM composition differs between women and changes over time. However, questions remain as to the underlying mechanisms and culture-dependent studies are needed for further elucidation of the HVM’s genotype-phenotype relationships and system-level properties in vivo. In this work, we have adapted a previously developed microdroplet-based high-throughput cultivation platform for the investigation of vaginal bacteria using the cervicovaginal fluid (CVF) as cultivation medium. Using undiluted CVF collected with Softdiscs discs, we observed the growth of L. iners in microdroplets containing CVF pooled from samples with a high prevalence of L. crispatus. Although demonstrated with L. iners, this work establishes a new framework for culturing microorganisms under clinically-relevant conditions ex vivo using minute volumes of host fluids; it can be further extended and adapted for addressing numerous questions about the HVM and other complex microbiomes.
Development and Optimization of Passive Sampling Methods for Surface Water and Sediment Porewater Measurements of Freely Dissolved Concentrations of Hydrophobic Organic Contaminant
(2024-01-01) Ghosh, Oindrila; Ghosh, Upal; Chemical, Biochemical & Environmental Engineering; Engineering, Civil and Environmental
Polychlorinated biphenyls (PCBs) are hydrophobic organic contaminants (HOCs) that have persisted in the environment for decades after production was banned by the USEPA in 1979. PCBs are known carcinogens and bioaccumulate into organisms through the aquatic food web, thereby posing threats to ecological and human health even at trace concentrations in the environment. The freely dissolved concentration in the aqueous phase (Cfree) is a useful indicator of chemical activity and is critical to determine exchange between environmental phases and bioaccumulation in organisms. Polymeric passive sampling (PS) provides time- integrated Cfree measurements in surface waters and sediment porewaters, unlike grab sampling that provides a snapshot of the concentration at one point in time. The primary objectives of this research were: (1) to understand the true nature of the time-integrative property of equilibrium PS under fluctuating ambient surface water concentrations, (2) to design PS devices (by manipulating their major rate-limiting zones for mass transfer so that approach to equilibrium is expedited) and develop field demonstrated PS prototypes that can perform (i) short-term measurements of HOCs in surface water during a storm event or (ii) address the challenges associated with Cfree porewater measurements for strongly hydrophobic compounds, (3) to develop standardized methods for impregnating performance reference compounds (PRCs) into PS (that helps determining the extent of a sampler’s approach to equilibrium) and calculating the cost of preparing PRC impregnated low density polyethylene (LDPE) samplers. The theoretical and modeling framework of exchange kinetics in PS developed in this study, was utilized to calculate sampling time scale of integration (TSI) and sensitivity (%) for various chemical-sampler pairs. This was used to develop and optimize the designs of PS devices for long- and short-term deployments in the field for accurate pore-water and surface water Cfree measurements. In high flow conditions, when diffusion is controlled by the sampler side, thin sheet PS (18 ?m PE) were used to perform short-term Cfree measurements over a stormflow event lasting for 42 hours in a PCB contaminated tributary to an urban river in Washington DC. Results indicated evidence of the tributary as a major source of PCB loading to the main river during stormflow conditions. In compact sediments, diffusion is controlled by the water boundary layer (WBL) external to the sampler. Mechanical disruption of the WBL outside the sampler by introducing periodic vibration on field demonstrated sampling devices showed that within compact sediments, PS reached at least 20% equilibrium in 8 days even for the more hydrophobic PCBs and dioxins/furans, as demonstrated by the depletion of PRCs from the samplers. Accurate measurements of Cfree in sediment porewater was possible by performing PRC corrections. Non homogenous PRC loading can lead to error prone estimations of fractional PRC losses used for correcting for non-equilibrium conditions. PRC stock solutions in nonane when spiked in methanol-water systems, homogenous impregnations of LDPE with overall RSD 4% was observed. The material-cost of preparing 1 g of LDPE at 200 ng/g from 80:20 methanol-water solutions was approximately $8.
Modeling time scale of integration in equilibrium passive sampling
(Oxford University Press, 2025-01-06) Ghosh, Oindrila; Yan, Songjing; Bokare, Mandar; Ghosh, Upal
Passive samplers (PSs) deployed in the field for several months provide a time-averaged measurement of the freely dissolved concentration of pollutants, which is important for assessing ecological exposure and estimating pollutant loads. A comprehensive theoretical modeling assessment of the sampling time scale of integration (TSI) of an equilibrium PS is required to correctly interpret the results. We address this knowledge gap by modeling exchange kinetics of polychlorinated biphenyl congeners in low-density polyethylene (PE) PS based on diffusive transport and first-order kinetics. We evaluate the sampling TSI by analyzing the response of the PS to simulated pulsed concentration increases in the water column that lasted for 1 day in a total sampling period of 90 days. More hydrophobic compounds experience slower transfer into the sampler and show a longer TSI compared with less hydrophobic compounds. Similarly, a thick sampler shows longer TSI than a thinner sampler. The sampling TSI for a typical 25.4 ?m PE sheet ranged widely from 14� days for a dichlorobiphenyl to 43� days for a hexachlorobiphenyl. We show that strategic deployment of a thick and thin passive sampler can be used to narrow the range of TSIs for all congeners and used to simultaneously capture episodic events along with long-term averages.
Current Strategies and Future Directions of Wearable Biosensors for Measuring Stress Biochemical Markers for Neuropsychiatric Applications
(Wiley, 2024-12-17) Sheffield, Zach; Paul, Priyanka; Krishnakumar, Shraddha; Pan, Prof Dipanjan
Most wearable biosensors aimed at capturing psychological state target stress biomarkers in the form of physical symptoms that can correlate with dysfunction in the central nervous system (CNS). However, such markers lack the specificity needed for diagnostic or preventative applications. Wearable biochemical sensors (WBSs) have the potential to fill this gap, however, the technology is still in its infancy. Most WBSs proposed thus far target cortisol. Although cortisol detection is demonstrated as a viable method for approximating the extent and severity of psychological stress, the hormone also lacks specificity. Multiplex WBSs that simultaneously target cortisol alongside other viable stress-related biochemical markers (SBMs) can prove to be indispensable for understanding how psychological stress contributes to the pathophysiology of neuropsychiatric illnesses (NPIs) and, thus, lead to the discovery of new biomarkers and more objective clinical tools. However, none target more than one SBM implicated in NPIs. Till this review, cortisol's connection to dysfunctions in the CNS, to other SBMs, and their implication in various NPIs has not been discussed in the context of developing WBS technology. As such, this review is meant to inform the biosensing and neuropsychiatric communities of viable future directions and possible challenges for WBS technology for neuropsychiatric applications.

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