| 11. |
- Ugawa, Masashi, et al.
(author)
-
Reduced acoustic resonator dimensions improve focusing efficiency of bacteria and submicron particles
- 2022
-
In: Analyst. - : Royal Society of Chemistry (RSC). - 1364-5528. ; 147:2, s. 274-281
-
Journal article (peer-reviewed)abstract
- In this study, we demonstrate an acoustofluidic device that enables single-file focusing of submicron particles and bacteria using a two-dimensional (2D) acoustic standing wave. The device consists of a 100 μm × 100 μm square channel that supports 2D particle focusing in the channel center at an actuation frequency of 7.39 MHz. This higher actuation frequency compared with conventional bulk acoustic systems enables radiation-force-dominant motion of submicron particles and overcomes the classical size limitation (≈2 μm) of acoustic focusing. We present acoustic radiation force-based focusing of particles with diameters less than 0.5 μm at a flow rate of 12 μL min−1, and 1.33 μm particles at flow rates up to 80 μL min−1. The device focused 0.25 μm particles by the 2D acoustic radiation force while undergoing a channel cross-section centered, single-vortex acoustic streaming. A suspension of bacteria was also investigated to evaluate the biological relevance of the device, which demonstrated the alignment of bacteria in the channel at aflow rate of up to 20 μL min−1. The developed acoustofluidic device can align submicron particles within a narrow flow stream in a highly robust manner, validating its use as a flow-through focusing chamber to perform high-throughput and accurate flow cytometry of submicron objects
|
|
| 12. |
- Wuensch, Urban, 1986, et al.
(author)
-
Mathematical chromatography deciphers the molecular a of dissolved organic matter
- 2020
-
In: The Analyst. - 0003-2654 .- 1364-5528. ; 145:5, s. 1789-1800
-
Journal article (peer-reviewed)abstract
- High-resolution mass spectrometry (HRMS) elucidates the molecular composition of dissolved organic matter (DOM) through the unequivocal assignment of molecular formulas. When HRMS is used as a detector coupled to high performance liquid chromatography (HPLC), the molecular fingerprints of DOM are further augmented. However, the identification of eluting compounds remains impossible when DOM chromatograms consist of unresolved humps. Here, we utilized the concept of mathematical chromatography to achieve information reduction and feature extraction. Parallel Factor Analysis (PARAFAC) was applied to a dataset describing the reverse-phase separation of DOM in headwater streams located in southeast Sweden. A dataset consisting of 1355 molecular formulas and 7178 mass spectra was reduced to five components that described 96.89% of the data. Each component summarized the distinct chromatographic elution of molecular formulas with different polarity. Component scores represented the abundance of the identified HPLC features in each sample. Using this chemometric approach allowed the identification of common patterns in HPLC–HRMS datasets by reducing thousands of mass spectra to only a few statistical components. Unlike in principal component analysis (PCA), components closely followed the analytical principles of HPLC–HRMS and therefore represented more realistic pools of DOM. This approach provides a wealth of new opportunities for unravelling the composition of complex mixtures in natural and engineered systems.
|
|
| 13. |
- Wunsch, Urban J., et al.
(author)
-
Mathematical chromatography deciphers the molecular fingerprints of dissolved organic matter
- 2020
-
In: The Analyst. - : ROYAL SOC CHEMISTRY. - 0003-2654 .- 1364-5528. ; 145:5, s. 1789-1800
-
Journal article (peer-reviewed)abstract
- High-resolution mass spectrometry (HRMS) elucidates the molecular composition of dissolved organic matter (DOM) through the unequivocal assignment of molecular formulas. When HRMS is used as a detector coupled to high performance liquid chromatography (HPLC), the molecular fingerprints of DOM are further augmented. However, the identification of eluting compounds remains impossible when DOM chromatograms consist of unresolved humps. Here, we utilized the concept of mathematical chromatography to achieve information reduction and feature extraction. Parallel Factor Analysis (PARAFAC) was applied to a dataset describing the reverse-phase separation of DOM in headwater streams located in southeast Sweden. A dataset consisting of 1355 molecular formulas and 7178 mass spectra was reduced to five components that described 96.89% of the data. Each component summarized the distinct chromatographic elution of molecular formulas with different polarity. Component scores represented the abundance of the identified HPLC features in each sample. Using this chemometric approach allowed the identification of common patterns in HPLC-HRMS datasets by reducing thousands of mass spectra to only a few statistical components. Unlike in principal component analysis (PCA), components closely followed the analytical principles of HPLC-HRMS and therefore represented more realistic pools of DOM. This approach provides a wealth of new opportunities for unravelling the composition of complex mixtures in natural and engineered systems.
|
|
| 14. |
- Yalovenko, N., et al.
(author)
-
Analyzing glycans cleaved from a biotherapeutic protein using ultrahigh-resolution ion mobility spectrometry together with cryogenic ion spectroscopy
- 2020
-
In: Analyst. - : Royal Society of Chemistry (RSC). - 0003-2654. ; 145:20, s. 6493-6499
-
Journal article (peer-reviewed)abstract
- Glycans covalently attached to protein biotherapeutics have a significant impact on their biological activity, clearance, and safety. As a result, glycosylation is categorized as a critical quality attribute that needs an adequate analytical approach to guarantee product quality. However, the isomeric complexity and branched structure of glycans makes their analysis a significant challenge. In this work, we propose a multidimensional approach for monitoring released glycans that combines ultrahigh-resolution ion mobility spectrometry (IMS) and cryogenic vibrational spectroscopy, and we demonstrate this technique by characterizing fourN-glycans cleaved from the therapeutic fusion protein etanercept that range in abundance from 1% to 22% of the totalN-glycan content. The recorded vibrational spectra exhibit well-resolved transitions that can be used as a fingerprint to identify a particular glycan. This work represents an important advance in the analysis of N-linked glycans cleaved from biopharmaceutical proteins that could eventually be used as tool for monitoring biopharmaceutical glycoforms.
|
|
| 15. |
- Zhang, Lei, et al.
(author)
-
Selective mercury(ii) detection in aqueous solutions upon the absorption changes corresponding to the transition moments polarized along the short axis of an azobenzene chemosensor
- 2020
-
In: The Analyst. - : Royal Society of Chemistry (RSC). - 0003-2654 .- 1364-5528. ; 145:5, s. 1641-1645
-
Journal article (peer-reviewed)abstract
- A completely water soluble azobenzene chemosensor 1 for selective detection of Hg2+ was synthesized. Taking advantage of the absorption changes corresponding to the transition moments polarized along the short axis of an azobenzene, 1 showed characteristic UV-Vis signal changes in the band around 240 nm for Hg2+ in wide pH ranges, which also showed good tolerance to various metal ions and photoirradiation. Upon addition of Hg2+ into the solution of 1, a favored formation of trans-1 was observed, which is attributed to an intramolecular coordination of the PEG chain and Nβ to Hg2+ confirmed by a control experiment test. © The Royal Society of Chemistry 2020.
|
|
| 16. |
|
|
| 17. |
- Öberg, Rasmus, et al.
(author)
-
Assessing CaDPA levels, metabolic activity, and spore detection through deuterium labeling
- 2024
-
In: The Analyst. - : Royal Society of Chemistry. - 0003-2654 .- 1364-5528. ; 149:6, s. 1861-1871
-
Journal article (peer-reviewed)abstract
- Many strains among spore-forming bacteria species are associated with food spoilage, foodborne disease, and hospital-acquired infections. Understanding the impact of environmental conditions and decontamination techniques on the metabolic activity, viability, and biomarkers of these spores is crucial for combatting them. To distinguish and track spores and to understand metabolic mechanisms, spores must be labeled. Staining or genetic modification are current methods for this, however, these methods can be time-consuming, and affect the viability and function of spore samples. In this work, we investigate the use of heavy water for permanent isotope labeling of spores and Raman spectroscopy for tracking sporulation/germination mechanisms. We also discuss the potential of this method in observing decontamination. We find that steady-state deuterium levels in the spore are achieved after only ∼48 h of incubation with 30% D2O-infused broth and sporulation, generating Raman peaks at cell silent region of 2200 and 2300 cm−1. These deuterium levels then decrease rapidly upon spore germination in non-deuterated media. We further find that unlike live spores, spores inactivated using various methods do not lose these Raman peaks upon incubation in growth media, suggesting these peaks may be used to indicate the viability of a spore sample. We further observe several Raman peaks exclusive to deuterated DPA, a spore-specific chemical biomarker, at e.g. 988 and 2300 cm−1, which can be used to track underlying changes in spores involving DPA. In conclusion, permanent spore labeling using deuterium offers a robust and non-invasive way of labeling bacterial spores for marking, viability determination, and characterising spore activity.
|
|
| 18. |
- Öberg, Rasmus, et al.
(author)
-
Monitoring bacterial spore metabolic activity using heavy water-induced Raman peak evolution
- 2023
-
In: The Analyst. - : Royal Society of Chemistry. - 0003-2654 .- 1364-5528. ; 148:9, s. 2141-2148
-
Journal article (peer-reviewed)abstract
- Endospore-forming bacteria are associated with food spoilage, food poisoning, and infection in hospitals. Therefore, methods to monitor spore metabolic activity and verify sterilization are of great interest. However, current methods for tracking metabolic activity are time-consuming and resource intensive. This work investigates isotope labeling and Raman microscopy as a low-cost rapid alternative. Specifically, we monitor the Raman spectrum of enterotoxic \textit{B. cereus} spores undergoing germination and cell division in D2O-infused broth. During germination and cell division, water is metabolized and deuterium from the broth is incorporated into proteins and lipids, resulting in the appearance of a Raman peak related to C-D bonds at 2190 cm-1. We find that a significant C-D peak appears after 2 h of incubation at 37◦C. Further, we found that the peak appearance coincides with the observed first cell division indicating little metabolic activity during germination. Lastly, the germination and cell growth rate of spores were not affected by adding 30 % heavy water to the broth. This shows the potential for real-time monitoring of metabolic activity from a bacterial spore to a dividing cell. In conclusion, our work proposes tracking the evolution of the C-D Raman peak in spores incubated with D2O-infused broth as an effective and time-, and cost-efficient method to monitor the outgrowth of a spore population, simultaneously allowing us to track for how long the bacteria have grown and divided.
|
|
