1
|
Pradhan SR, Pathinti RS, Kandimalla R, Chithari K, Veeramalla N MR, Vallamkondu J. Label-free detection of Aβ-42: a liquid crystal droplet approach for Alzheimer's disease diagnosis. RSC Adv 2024; 14:12107-12118. [PMID: 38628477 PMCID: PMC11019351 DOI: 10.1039/d4ra00615a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Accepted: 04/09/2024] [Indexed: 04/19/2024] Open
Abstract
This study introduces a biosensor based on liquid crystals (LC) designed to detect the Aβ-42 biomarker, commonly associated with Alzheimer's disease. The sensor utilizes LC droplets created using a PEI/Tween-20 surfactant mixture, arranged radially in an aqueous solution. These droplets are coated with the Aβ1-16 antibody, enabling the detection of the Aβ1-42 biomarker. The key advantage of this biosensor lies in its ability to directly translate the antigen-antibody interaction into a change in the molecular orientation of the LC droplets, simplifying the detection process by removing additional procedural steps. Specifically, this immunoassay induces a transformation in the nematic droplets orientation from radial to bipolar upon successful antigen binding. When only the Aβ1-16 antibody coated the LC droplets, no change in orientation was detected, confirming the reaction's specificity. The orientation shift in the LC droplets indicates the formation of an immunocomplex between the Aβ1-16 antibody and the Aβ1-42 antigen. The LC droplet immunoassay effectively detected Aβ1-42 antigen concentrations ranging from 45 to 112.5 μM, with the Aβ1-16 antibody immobilized on the droplets at a concentration of 1 μg mL-1. These findings suggest that the LC microdroplets' orientational behavior can be harnessed to develop a biosensor for the in vivo detection of various proteins or pathogens in a PBS aqueous medium. Owing to its label-free nature and distinct optical signaling, this LC droplet-based immunoassay holds promise for further development into a cost-effective, portable diagnostic tool.
Collapse
Affiliation(s)
| | | | - Ramesh Kandimalla
- Department of Biochemistry, Kakatiya Medical College Warangal 506007 India
| | | | | | | |
Collapse
|
2
|
Piñeres-Quiñones OH, Oñate-Socarras MK, Wang F, Lynn DM, Acevedo-Vélez C. Pickering Emulsions of Thermotropic Liquid Crystals Stabilized by Amphiphilic Gold Nanoparticles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024. [PMID: 38320298 DOI: 10.1021/acs.langmuir.3c03940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2024]
Abstract
We report emulsions of thermotropic liquid crystals (LCs) in water that are stabilized using amphiphilic gold nanoparticles (AuNPs) and retain their ability to respond to aqueous analytes for extended periods (e.g., up to 1 year after preparation). These LC emulsions exhibit exceptional colloidal stability that results from the adsorption of AuNPs that are functionalized with thiol-terminated poly(ethylene glycol) (PEG-thiol) and hexadecanethiol (C16-thiol) to LC droplet interfaces. These stabilized LC emulsions respond to the presence of model anionic (SDS), cationic (C12TAB), and nonionic (C12E4) surfactants in the surrounding aqueous media, as evidenced by ordering transitions in the LC droplets that can be readily observed using polarized light microscopy. Our results reveal significant differences in the sensitivity of the stabilized LC droplets toward each of these analytes. In particular, these stabilized droplets can detect the cationic C12TAB at concentrations that are lower than those required for bare LC droplets under similar experimental conditions (0.5 and 2 mM, respectively). These results demonstrate an enhanced sensitivity of the LC toward C12TAB when the PEG/C16-thiol-coated AuNPs are adsorbed at LC droplet interfaces. In contrast, the concentrations of SDS required to observe optical transformations in the stabilized LC droplets are higher than those required for the bare LC droplets, suggesting that the presence of the PEG/C16-thiol AuNPs reduces the sensitivity of the LC toward this analyte. When combined, our results show that this Pickering stabilization approach using amphiphilic AuNPs as stabilizing agents for LC-in-water emulsions provides a promising platform for developing LC droplet-based optical sensors with long-term colloidal stability as well as opportunities to tune the sensitivity and selectivity of the response to target aqueous analytes.
Collapse
Affiliation(s)
- Oscar H Piñeres-Quiñones
- Department of Chemical Engineering, University of Puerto Rico-Mayagüez, Call Box 9000, Mayagüez, PR 00681-9000, United States
| | - Maria K Oñate-Socarras
- Department of Chemical Engineering, University of Puerto Rico-Mayagüez, Call Box 9000, Mayagüez, PR 00681-9000, United States
| | - Fengrui Wang
- Department of Chemistry, 1101 University Avenue, University of Wisconsin─Madison, Madison, Wisconsin 53706, United States
| | - David M Lynn
- Department of Chemistry, 1101 University Avenue, University of Wisconsin─Madison, Madison, Wisconsin 53706, United States
- Department of Chemical and Biological Engineering, 1415 Engineering Drive, University of Wisconsin─Madison, Madison, Wisconsin 53706, United States
| | - Claribel Acevedo-Vélez
- Department of Chemical Engineering, University of Puerto Rico-Mayagüez, Call Box 9000, Mayagüez, PR 00681-9000, United States
| |
Collapse
|
3
|
Shadkami R, Chan PK. Computational Analysis on the Performance of Elongated Liquid Crystal Biosensors. MICROMACHINES 2023; 14:1831. [PMID: 37893268 PMCID: PMC10609392 DOI: 10.3390/mi14101831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 09/18/2023] [Accepted: 09/21/2023] [Indexed: 10/29/2023]
Abstract
Elongated ellipsoidal liquid crystal microdroplet reorientation dynamics are discussed in this paper for biosensor applications. To investigate the effect of elongated droplets on nematic liquid crystal droplet biosensors, we simulated a model of a liquid crystal droplet using ellipse geometry. Director reorientation is examined in relation to the elongated droplet shape. In addition, we examined aspect ratio as a factor affecting biosensor response time in relation to surface viscosity and anchoring energy. Finally, the findings suggest that the aspect ratio should be taken into account when designing biosensors. These results can be used to develop more effective biosensors for a variety of applications. This model then predicts the director reorientation angle, which is dependent on the anchoring energy and surface viscosity. This model further suggests that both surface viscosity and homeotropic anchoring energy play an important role when it comes to the director reorientation angle. We developed and applied a nonlinear unsteady-state mathematical model utilizing torque balance and Frank free energy according to the Leslie-Ericksen continuum theory for simulating elongated nematic liquid crystal biosensor droplets with aqueous interfaces. Using the Euler-Lagrange equation, a transient liquid crystal-aqueous interface realignment is modeled by changing the easy axis when surfactant molecules are added to the interface. The realignment at the surface of the droplet is assumed to be driven by the effect of the surfactant, which causes an anchoring transition. According to the results, the response time of the biosensor depends on the aspect ratio. Therefore, the elongation has the potential to control biosensing response time. The result of our study provides a better understanding of director reorientation in elongated liquid crystal droplets in biosensing applications through the numerical results which are presented in this paper.
Collapse
Affiliation(s)
| | - Philip K. Chan
- Department of Chemical Engineering, Toronto Metropolitan University, 350 Victoria Street, Toronto, ON M5B 2K3, Canada;
| |
Collapse
|
4
|
Jennings J, Pabst G. Multiple Routes to Bicontinuous Cubic Liquid Crystal Phases Discovered by High-Throughput Self-Assembly Screening of Multi-Tail Lipidoids. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023:e2206747. [PMID: 37026678 DOI: 10.1002/smll.202206747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 03/16/2023] [Indexed: 06/19/2023]
Abstract
Bicontinuous cubic phases offer advantageous routes to a broad range of applied materials ranging from drug delivery devices to membranes. However, a priori design of molecules that assemble into these phases remains a technological challenge. In this article, a high-throughput synthesis of lipidoids that undergo protonation-driven self-assembly (PrSA) into liquid crystalline (LC) phases is conducted. With this screening approach, 12 different multi-tail lipidoid structures capable of assembling into the bicontinuous double gyroid phase are discovered. The large volume of small-angle X-ray scattering (SAXS) data uncovers unexpected design criteria that enable phase selection as a function of lipidoid headgroup size and architecture, tail length and architecture, and counterion identity. Surprisingly, combining branched headgroups with bulky tails forces lipidoids to adopt unconventional pseudo-disc conformations that pack into double gyroid networks, entirely distinct from other synthetic or biological amphiphiles within bicontinuous cubic phases. From a multitude of possible applications, two examples of functional materials from lipidoid liquid crystals are demonstrated. First, the fabrication of gyroid nanostructured films by interfacial PrSA, which are rapidly responsive to the external medium. Second, it is shown that colloidally-dispersed lipidoid cubosomes, for example, for drug delivery, are easily assembled using top-down solvent evaporation methods.
Collapse
Affiliation(s)
- James Jennings
- Institute of Molecular Biosciences, University of Graz, NAWI Graz, Graz, 8010, Austria
- Field of Excellence BioHealth, University of Graz, Graz, 8010, Austria
| | - Georg Pabst
- Institute of Molecular Biosciences, University of Graz, NAWI Graz, Graz, 8010, Austria
- Field of Excellence BioHealth, University of Graz, Graz, 8010, Austria
| |
Collapse
|
5
|
Wang H, Xu T, Fu Y, Wang Z, Leeson MS, Jiang J, Liu T. Liquid Crystal Biosensors: Principles, Structure and Applications. BIOSENSORS 2022; 12:bios12080639. [PMID: 36005035 PMCID: PMC9406233 DOI: 10.3390/bios12080639] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 08/06/2022] [Accepted: 08/12/2022] [Indexed: 12/31/2022]
Abstract
Liquid crystals (LCs) have been widely used as sensitive elements to construct LC biosensors based on the principle that specific bonding events between biomolecules can affect the orientation of LC molecules. On the basis of the sensing interface of LC molecules, LC biosensors can be classified into three types: LC–solid interface sensing platforms, LC–aqueous interface sensing platforms, and LC–droplet interface sensing platforms. In addition, as a signal amplification method, the combination of LCs and whispering gallery mode (WGM) optical microcavities can provide higher detection sensitivity due to the extremely high quality factor and the small mode volume of the WGM optical microcavity, which enhances the interaction between the light field and biotargets. In this review, we present an overview of the basic principles, the structure, and the applications of LC biosensors. We discuss the important properties of LC and the principle of LC biosensors. The different geometries of LCs in the biosensing systems as well as their applications in the biological detection are then described. The fabrication and the application of the LC-based WGM microcavity optofluidic sensor in the biological detection are also introduced. Finally, challenges and potential research opportunities in the development of LC-based biosensors are discussed.
Collapse
Affiliation(s)
- Haonan Wang
- School of Precision Instruments and Opto-Electronics Engineering, Tianjin University, Tianjin 300072, China
| | - Tianhua Xu
- School of Precision Instruments and Opto-Electronics Engineering, Tianjin University, Tianjin 300072, China
- School of Engineering, University of Warwick, Coventry CV4 7AL, UK
- Correspondence: (T.X.); (J.J.)
| | - Yaoxin Fu
- School of Precision Instruments and Opto-Electronics Engineering, Tianjin University, Tianjin 300072, China
| | - Ziyihui Wang
- School of Precision Instruments and Opto-Electronics Engineering, Tianjin University, Tianjin 300072, China
- School of Electrical and Electronics Engineering, Nanyang Technological University, Singapore 639798, Singapore
| | - Mark S. Leeson
- School of Engineering, University of Warwick, Coventry CV4 7AL, UK
| | - Junfeng Jiang
- School of Precision Instruments and Opto-Electronics Engineering, Tianjin University, Tianjin 300072, China
- Correspondence: (T.X.); (J.J.)
| | - Tiegen Liu
- School of Precision Instruments and Opto-Electronics Engineering, Tianjin University, Tianjin 300072, China
| |
Collapse
|
6
|
Chiral Liquid Crystal Microdroplets for Sensing Phospholipid Amphiphiles. BIOSENSORS 2022; 12:bios12050313. [PMID: 35624614 PMCID: PMC9139120 DOI: 10.3390/bios12050313] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/17/2022] [Revised: 05/04/2022] [Accepted: 05/05/2022] [Indexed: 12/17/2022]
Abstract
Designing simple, sensitive, fast, and inexpensive readout devices to detect biological molecules and biomarkers is crucial for early diagnosis and treatments. Here, we have studied the interaction of the chiral liquid crystal (CLC) and biomolecules at the liquid crystal (LC)-droplet interface. CLC droplets with high and low chirality were prepared using a microfluidic device. We explored the reconfiguration of the CLC molecules confined in droplets in the presence of 1,2-diauroyl-sn-glycero3-phosphatidylcholine (DLPC) phospholipid. Cross-polarized optical microscopy and spectrometry techniques were employed to monitor the effect of droplet size and DLPC concentration on the structural reorganization of the CLC molecules. Our results showed that in the presence of DLPC, the chiral LC droplets transition from planar to homeotropic ordering through a multistage molecular reorientation. However, this reconfiguration process in the low-chirality droplets happened three times faster than in high-chirality ones. Applying spectrometry and image analysis, we found that the change in the chiral droplets’ Bragg reflection can be correlated with the CLC–DLPC interactions.
Collapse
|
7
|
Şengül S, Aydoğan N, Bukusoglu E. Nanoparticle adsorption induced configurations of nematic liquid crystal droplets. J Colloid Interface Sci 2022; 608:2310-2320. [PMID: 34774320 DOI: 10.1016/j.jcis.2021.10.156] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 09/01/2021] [Accepted: 10/25/2021] [Indexed: 11/24/2022]
Abstract
Nematic liquid crystal (LC) droplets have been widely used for the detection of molecular species. We investigate the response of micrometer sized nematic LC droplets against the adsorption of nanoparticles from aqueous media. We synthesized ∼ 100 nm-in-diameter silica nanoparticles and modified their surfaces to mediate either planar or homeotropic LC anchoring and a pH-dependent charge. We show surface functionality- and concentration-dependent configurations of the droplets consistent with the change in the surface anchoring and the formation of local heterogeneities upon adsorption of the nanoparticles to LC-aqueous interfaces. The adsorption of nanoparticles modified with dimethyloctadecyl [3-(trimethoxysilyl) propyl] ammonium chloride (DMOAP, homeotropic) exhibit a transition from bipolar to radial, whereas the adsorption of -COOH-terminated counterparts (planar) did not cause a configuration transition. By manipulating the electrostatic interactions, we controlled the adsorption of the nanoparticles to the LC-aqueous interfaces, providing access to the physicochemical properties of the nanoparticles. We demonstrate a temporal change in the droplet configurations caused by the adsorption of the nanoparticles functionalized with -COOH/DMOAP mixed monolayers. These results provide a basis for studies in applications for the detection of nano-sized species, for sensing applications that combine nanoparticles with LCs, and for the synthesis of anisotropic composite particles with complex structures.
Collapse
Affiliation(s)
- Selin Şengül
- Department of Chemical Engineering, Middle East Technical University, Dumlupınar Bulvarı No:1, Çankaya 06800, Ankara, Turkey
| | - Nihal Aydoğan
- Department of Chemical Engineering, Hacettepe University, Beytepe 06800, Ankara, Turkey
| | - Emre Bukusoglu
- Department of Chemical Engineering, Middle East Technical University, Dumlupınar Bulvarı No:1, Çankaya 06800, Ankara, Turkey.
| |
Collapse
|
8
|
Piñeres-Quiñones OH, Lynn DM, Acevedo-Vélez C. Environmentally Responsive Emulsions of Thermotropic Liquid Crystals with Exceptional Long-Term Stability and Enhanced Sensitivity to Aqueous Amphiphiles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:957-967. [PMID: 35001623 DOI: 10.1021/acs.langmuir.1c02278] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
We report colloidally stable emulsions of thermotropic liquid crystals (LCs) that can detect the presence of amphiphilic analytes in aqueous environments. Our approach makes use of a Pickering stabilization strategy consisting of surfactant-nanoparticle complexes (SiO2/CnTAB, n = 8, 12, 16) that adsorb to aqueous/LC droplet interfaces. This strategy can stabilize LC emulsions against coalescence for at least 3 months. These stabilized LC emulsions also retain the ability to respond to the presence of model anionic, cationic, and nonionic amphiphiles (e.g., SDS, C12TAB, C12E4) in aqueous solutions by undergoing "bipolar-to-radial" changes in LC droplet configurations that can be readily observed and quantified using polarized light microscopy. Our results reveal these ordering transitions to depend upon the length of the hydrocarbon tail of the CnTAB surfactant used to form the stabilizing complexes. In general, increasing CnTAB surfactant tail length leads to droplets that respond at lower analyte concentrations, demonstrating that this Pickering stabilization strategy can be used to tune the sensitivities of the stabilized LC droplets. Finally, we demonstrate that these colloidally stable LC droplets can report the presence of rhamnolipid, a biosurfactant produced by the bacterial pathogen Pseudomonas aeruginosa. Overall, our results demonstrate that this Pickering stabilization strategy provides a useful tool for the design of LC droplet-based sensors with substantially improved colloidal stability and new strategies to tune their sensitivities. These advances could increase the potential practical utility of these responsive soft materials as platforms for the detection and reporting of chemical and biological analytes.
Collapse
Affiliation(s)
- Oscar H Piñeres-Quiñones
- Department of Chemical Engineering, University of Puerto Rico-Mayagüez, Call Box 9000, Mayagüez, Puerto Rico 00681-9000, United States
| | - David M Lynn
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, Wisconsin 53706, United States
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave., Madison, Wisconsin 53706, United States
| | - Claribel Acevedo-Vélez
- Department of Chemical Engineering, University of Puerto Rico-Mayagüez, Call Box 9000, Mayagüez, Puerto Rico 00681-9000, United States
| |
Collapse
|
9
|
Jiang S, Noh J, Park C, Smith AD, Abbott NL, Zavala VM. Using machine learning and liquid crystal droplets to identify and quantify endotoxins from different bacterial species. Analyst 2021; 146:1224-1233. [PMID: 33393547 DOI: 10.1039/d0an02220a] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Detection and quantification of bacterial endotoxins is important in a range of health-related contexts, including during pharmaceutical manufacturing of therapeutic proteins and vaccines. Here we combine experimental measurements based on nematic liquid crystalline droplets and machine learning methods to show that it is possible to classify bacterial sources (Escherichia coli, Pseudomonas aeruginosa, Salmonella minnesota) and quantify concentration of endotoxin derived from all three bacterial species present in aqueous solution. The approach uses flow cytometry to quantify, in a high-throughput manner, changes in the internal ordering of micrometer-sized droplets of nematic 4-cyano-4'-pentylbiphenyl triggered by the endotoxins. The changes in internal ordering alter the intensities of light side-scattered (SSC, large-angle) and forward-scattered (FSC, small-angle) by the liquid crystal droplets. A convolutional neural network (Endonet) is trained using the large data sets generated by flow cytometry and shown to predict endotoxin source and concentration directly from the FSC/SSC scatter plots. By using saliency maps, we reveal how EndoNet captures subtle differences in scatter fields to enable classification of bacterial source and quantification of endotoxin concentration over a range that spans eight orders of magnitude (0.01 pg mL-1 to 1 μg mL-1). We attribute changes in scatter fields with bacterial origin of endotoxin, as detected by EndoNet, to the distinct molecular structures of the lipid A domains of the endotoxins derived from the three bacteria. Overall, we conclude that the combination of liquid crystal droplets and EndoNet provides the basis of a promising analytical approach for endotoxins that does not require use of complex biologically-derived reagents (e.g., Limulus amoebocyte lysate).
Collapse
Affiliation(s)
- Shengli Jiang
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Dr, Madison, WI 53706, USA.
| | - JungHyun Noh
- Smith School of Chemical and Biomolecular Engineering, Cornell University, 113 Ho Plaza, Ithaca, NY 14853, USA.
| | - Chulsoon Park
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Dr, Madison, WI 53706, USA.
| | - Alexander D Smith
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Dr, Madison, WI 53706, USA.
| | - Nicholas L Abbott
- Smith School of Chemical and Biomolecular Engineering, Cornell University, 113 Ho Plaza, Ithaca, NY 14853, USA.
| | - Victor M Zavala
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Dr, Madison, WI 53706, USA.
| |
Collapse
|
10
|
Jennings J, Carter MCD, Son CY, Cui Q, Lynn DM, Mahanthappa MK. Protonation-Driven Aqueous Lyotropic Self-Assembly of Synthetic Six-Tail Lipidoids. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:8240-8252. [PMID: 32649210 DOI: 10.1021/acs.langmuir.0c01369] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We report the aqueous lyotropic mesophase behaviors of protonated amine-based "lipidoids," a class of synthetic lipid-like molecules that mirrors essential structural features of the multitail bacterial amphiphile lipid A. Small-angle X-ray scattering (SAXS) studies demonstrate that the protonation of the tetra(amine) headgroups of six-tail lipidoids in aqueous HCl, HNO3, H2SO4, and H3PO4 solutions variably drives their self-assembly into lamellar (Lα) and inverse micellar (III) lyotropic liquid crystals (LLCs), depending on acid identity and concentration, amphiphile tail length, and temperature. Lipidoid assemblies formed in H2SO4(aq) exhibit rare inverse body-centered cubic (BCC) and inverse face-centered cubic (FCC) micellar morphologies, the latter of which unexpectedly coexists with zero mean curvature Lα phases. Complementary atomistic molecular dynamics (MD) simulations furnish detailed insights into this unusual self-assembly behavior. The unique aqueous lyotropic mesophase behaviors of ammonium lipidoids originate in their dichotomous ability to adopt both inverse conical and chain-extended molecular conformations depending on the number of counterions and their identity, which lead to coexisting supramolecular assemblies with remarkably different mean interfacial curvatures.
Collapse
Affiliation(s)
| | | | | | | | | | - Mahesh K Mahanthappa
- Department of Chemical Engineering & Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, United States
| |
Collapse
|
11
|
Ortiz BJ, Boursier ME, Barrett KL, Manson DE, Amador-Noguez D, Abbott NL, Blackwell HE, Lynn DM. Liquid Crystal Emulsions That Intercept and Report on Bacterial Quorum Sensing. ACS APPLIED MATERIALS & INTERFACES 2020; 12:29056-29065. [PMID: 32484648 PMCID: PMC7343617 DOI: 10.1021/acsami.0c05792] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We report aqueous emulsions of thermotropic liquid crystals (LCs) that can intercept and report on the presence of N-acyl-l-homoserine lactones (AHLs), a class of amphiphiles used by pathogenic bacteria to regulate quorum sensing (QS), monitor population densities, and initiate group activities, including biofilm formation and virulence factor production. The concentration of AHL required to promote "bipolar" to "radial" transitions in micrometer-scale droplets of the nematic LC 4'-pentyl-cyanobiphenyl (5CB) decreases with increasing carbon number in the acyl tail, reaching a threshold concentration of 7.1 μM for 3-oxo-C12-AHL, a native QS signal in the pathogen Pseudomonas aeruginosa. The LC droplets in these emulsions also respond to biologically relevant concentrations of the biosurfactant rhamnolipid, a virulence factor produced by communities of P. aeruginosa under the control of QS. Systematic studies using bacterial mutants support the conclusion that these emulsions respond selectively to the production of rhamnolipid and AHLs and not to other products produced by bacteria at lower (subquorate) population densities. Finally, these emulsions remain configurationally stable in growth media, enabling them to be deployed either in bacterial supernatants or in situ in bacterial cultures to eavesdrop on QS and report on changes in bacterial group behavior that can be detected in real time using polarized light. Our results provide new tools to detect and report on bacterial QS and virulence and a materials platform for the rapid and in situ monitoring of bacterial communication and resulting group behaviors in bacterial communities.
Collapse
Affiliation(s)
- Benjamín J Ortiz
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, Wisconsin 53706, United States
| | - Michelle E Boursier
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Kelsey L Barrett
- Department of Bacteriology, University of Wisconsin-Madison, 1550 Linden Drive, Madison, Wisconsin 53706, United States
| | - Daniel E Manson
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Daniel Amador-Noguez
- Department of Bacteriology, University of Wisconsin-Madison, 1550 Linden Drive, Madison, Wisconsin 53706, United States
| | - Nicholas L Abbott
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, Wisconsin 53706, United States
| | - Helen E Blackwell
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - David M Lynn
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, Wisconsin 53706, United States
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| |
Collapse
|
12
|
Kim YK, Noh J, Nayani K, Abbott NL. Soft matter from liquid crystals. SOFT MATTER 2019; 15:6913-6929. [PMID: 31441481 DOI: 10.1039/c9sm01424a] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Liquid crystals (LCs) are fluids within which molecules exhibit long-range orientational order, leading to anisotropic properties such as optical birefringence and curvature elasticity. Because the ordering of molecules within LCs can be altered by weak external stimuli, LCs have been widely used to create soft matter systems that respond optically to electric fields (LC display), temperature (LC thermometer) or molecular adsorbates (LC chemical sensor). More recent studies, however, have moved beyond investigations of optical responses of LCs to explore the design of complex LC-based soft matter systems that offer the potential to realize more sophisticated functions (e.g., autonomous, self-regulating chemical responses to mechanical stimuli) by directing the interactions of small molecules, synthetic colloids and living cells dispersed within the bulk of LCs or at their interfaces. These studies are also increasingly focusing on LC systems driven beyond equilibrium states. This review presents one perspective on these advances, with an emphasis on the discovery of fundamental phenomena that may enable new technologies. Three areas of progress are highlighted; (i) directed assembly of amphiphilic molecules either within topological defects of LCs or at aqueous interfaces of LCs, (ii) templated polymerization in LCs via chemical vapor deposition, an approach that overcomes fundamental challenges related to control of LC phase behavior during polymerization, and (iii) studies of colloids in LCs, including chiral colloids, soft colloids that are strained by LCs, and active colloids that are driven into organized states by dissipation of energy (e.g. bacteria). These examples, and key unresolved issues discussed at the end of this perspective, serve to convey the message that soft matter systems that integrate ideas from LC, surfactant, polymer and colloid sciences define fertile territory for fundamental studies and creation of future transformative technologies.
Collapse
Affiliation(s)
- Young-Ki Kim
- Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, 113 Ho Plaza, Ithaca, New York 14853, USA. and Department of Chemical Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang, Gyengbuk 37673, Korea
| | - JungHyun Noh
- Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, 113 Ho Plaza, Ithaca, New York 14853, USA.
| | - Karthik Nayani
- Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, 113 Ho Plaza, Ithaca, New York 14853, USA.
| | - Nicholas L Abbott
- Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, 113 Ho Plaza, Ithaca, New York 14853, USA.
| |
Collapse
|
13
|
Chattaraj R, Blum NT, Goodwin AP. Design and Application of Stimulus-Responsive Droplets and Bubbles Stabilized by Phospholipid Monolayers. Curr Opin Colloid Interface Sci 2019; 40:14-24. [PMID: 31086500 PMCID: PMC6510502 DOI: 10.1016/j.cocis.2018.10.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Biomimetic colloidal particles are promising agents for biosensing, but current technologies fall far short of Nature's capabilities for sensing, assessing, and responding to stimuli. Phospholipid-containing cell membranes are capable of binding and responding to an enormous variety of biomolecules by virtue of membrane organization and the presence of receptor proteins. By tuning the composition and functionalization of simulated membranes, soft colloids such as droplets and bubbles can be designed to respond to various stimuli. Moreover, because lipid monolayers can surround almost any hydrophobic phase, the interior of the colloid can be selected to provide a sensitive readout, for example in the form of optical microscopy or acoustic detection. In this work, we review some advances made by our group and others in the formulation of lipid-coated particles with different internal phases such as fluorocarbons, hydrocarbons, or liquid crystals. In some cases, binding or displacement of stabilizing lipids gives rise to conformational changes or disruptions in local membrane geometry, which can be amplified by the interior phase. In other cases, multivalent analytes can promote aggregation or even membrane fusion, which can be utilized for optical or acoustic readout. By highlighting a few recent examples, we hope to show that lipid monolayers represent an extremely versatile biosensing platform that can react to and detect biomolecules by leveraging the unique capabilities of phospholipid membranes.
Collapse
Affiliation(s)
- Rajarshi Chattaraj
- Department of Mechanical Engineering, University of Colorado Boulder. Boulder, CO 80309
| | - Nicholas T. Blum
- Department of Chemical and Biological Engineering. University of Colorado Boulder. Boulder, CO 80303
| | - Andrew P. Goodwin
- Department of Chemical and Biological Engineering. University of Colorado Boulder. Boulder, CO 80303
| |
Collapse
|
14
|
Dubtsov AV, Pasechnik SV, Shmeliova DV, Saidgaziev AS, Gongadze E, Iglič A, Kralj S. Liquid crystalline droplets in aqueous environments: electrostatic effects. SOFT MATTER 2018; 14:9619-9630. [PMID: 30457151 DOI: 10.1039/c8sm01529e] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We demonstrate the strong impact of electrostatic properties on radial-bipolar structural transitions in nematic liquid crystal (LC) droplets dispersed in different aqueous environments. In the experimental part of the study, we systematically changed the electrostatic properties of both LC droplets and aqueous solutions. Mixtures of nematics were studied by combining LC materials with negative (azoxybenzene compounds) and strongly positive (cyanobiphenyl) dielectric anisotropy. The aqueous solutions were manipulated by introducing either polyvinyl alcohol, glycerol, electrolyte or amphiphilic anionic surfactant SDS into water. In the supporting theoretical study, we identified the key parameters influencing the dielectric constant and the electric field strength of aqueous solutions. We also estimated the impact of different electrolytes on the Debye length at the LC-aqueous interface. The obtained results are further analysed for chemical and biological sensing applications.
Collapse
Affiliation(s)
- Alexander V Dubtsov
- Problem Laboratory of Molecular Acoustics, MIREA - Russian Technological University, 119454, 78 Vernadsky Avenue, Moscow, Russia.
| | | | | | | | | | | | | |
Collapse
|
15
|
Kell DB, Pretorius E. To What Extent Are the Terminal Stages of Sepsis, Septic Shock, Systemic Inflammatory Response Syndrome, and Multiple Organ Dysfunction Syndrome Actually Driven by a Prion/Amyloid Form of Fibrin? Semin Thromb Hemost 2017; 44:224-238. [PMID: 28778104 PMCID: PMC6193370 DOI: 10.1055/s-0037-1604108] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
A well-established development of increasing disease severity leads from sepsis through systemic inflammatory response syndrome, septic shock, multiple organ dysfunction syndrome, and cellular and organismal death. Less commonly discussed are the equally well-established coagulopathies that accompany this. We argue that a lipopolysaccharide-initiated (often disseminated intravascular) coagulation is accompanied by a proteolysis of fibrinogen such that formed fibrin is both inflammatory and resistant to fibrinolysis. In particular, we argue that the form of fibrin generated is amyloid in nature because much of its normal α-helical content is transformed to β-sheets, as occurs with other proteins in established amyloidogenic and prion diseases. We hypothesize that these processes of amyloidogenic clotting and the attendant coagulopathies play a role in the passage along the aforementioned pathways to organismal death, and that their inhibition would be of significant therapeutic value, a claim for which there is considerable emerging evidence.
Collapse
Affiliation(s)
- Douglas B Kell
- School of Chemistry, The University of Manchester, Manchester, United Kingdom.,Manchester Institute of Biotechnology, The University of Manchester, Manchester, United Kingdom.,Centre for Synthetic Biology of Fine and Speciality Chemicals, The University of Manchester, Manchester, United Kingdom
| | - Etheresia Pretorius
- Department of Physiological Sciences, Stellenbosch University, Matieland, South Africa
| |
Collapse
|
16
|
Proteins behaving badly. Substoichiometric molecular control and amplification of the initiation and nature of amyloid fibril formation: lessons from and for blood clotting. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2017; 123:16-41. [DOI: 10.1016/j.pbiomolbio.2016.08.006] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2016] [Revised: 08/14/2016] [Accepted: 08/19/2016] [Indexed: 02/08/2023]
|
17
|
Popov P, Mann EK, Jákli A. Thermotropic liquid crystal films for biosensors and beyond. J Mater Chem B 2017; 5:5061-5078. [DOI: 10.1039/c7tb00809k] [Citation(s) in RCA: 118] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Recent results on structural properties and possible bio-sensing applications of planar liquid crystal films are reviewed.
Collapse
Affiliation(s)
- Piotr Popov
- Department of Physics
- Kent State University
- Kent
- USA
- Liquid Crystal Institute
| | | | - Antal Jákli
- Liquid Crystal Institute
- Kent State University
- Kent
- USA
- Complex Fluid Group
| |
Collapse
|