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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Bioinspired Macrocyclic Molecule Supported Two‐Dimensional Lamellar Membrane with Robust Interlayer Structure for High‐Efficiency Nanofiltration

Abstract 2D lamellar membranes (2DLMs) are used for efficient desalination and nanofiltration. However, weak interactions between adjacent stacked nanosheets result in susceptibility to swelling that limits practical applicability. Inspired by the super adhesion of multi‐point suction cups on octopus tentacles, a 2DLM is constructed from Ti 3 C 2 T x MXene supported by the macrocyclic “multi‐point” molecule cucurbit[5]uril (CB5) and demonstrated for nanofiltration of methyl blue (MB) and enrichment of uranyl carbonate. Experimental results and density functional theory calculations indicate that CB5 rivets to the surface of the nanoflakes through strong stable interactions between its multiple binding sites and surface hydroxyl functional groups on MXene nanosheets. This novel 2DLM exhibits excellent nanofiltration performance (69 L m −2 h −1 bar −1 permeance with 93.6% rejection for MB) and can be recycled at least 30 times without significant degradation. The 2DLM exhibits excellent swelling resistance at high salinity, with a demonstration of selective enrichment of uranyl carbonate from artificial water and natural seawater. The results provide a new strategy for constructing highly stable 2DLMs with interlayer spacing controllable from sub‐nano to nanometer scales, for size‐selective sieving of molecules and ions, high‐efficiency nanofiltration, and other applications.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
DOE OSTI2023

Chemical-free production of multiple high-value bioproducts from metabolically engineered transgenic sugarcane ‘oilcane’ bagasse and their recovery using nanofiltration

Bioenergy crops have potential for being a sustainable and renewable feedstock for biofuels and various value- added bioproducts. The study utilizes recently developed transgenic sugarcane (‘oilcane’) bagasse for chemical- free coproduction of high-value bioproducts, i.e., furfurals, HMF, acetic acid, cellulosic sugars, and vegetative lipids. Hydrothermal pretreatment was optimized at 210°C for 5 min to coproduce 6.91%, 2.67%, 5.07%, 2.42% and 37.82% (w/w) furfurals, HMF, acetic acid, vegetative lipids, and cellulosic sugars, respectively from lignocellulosic biomass. Additionally, nanofiltration system in-series was successfully established to recover sugars, furfurals, HMF, and acetic acid from the pretreatment liquor. 1st nanofiltration with Duracid NF mem- brane rejected ~99% sugars. Concentrated sugars with significantly reduced inhibitory products were obtained in retentate for fermentation. 2nd nanofiltration with NF90 membrane used permeate of 1st nanofiltration as feed and rejected ~ 86% furfurals. Furthermore, the work demonstrates the feasibility of coproducing and recovering multiple biochemicals from lignocellulosic biomass.

09 BIOMASS FUELS↗
DOE OSTI2023

Data for Chemical-Free Production of Multiple High-Value Bioproducts from Metabolically Engineered Transgenic Sugarcane ‘Oilcane’ Bagasse and Their Recovery Using Nanofiltration

Bioenergy crops have potential for being a sustainable and renewable feedstock for biofuels and various value-added bioproducts. The study utilizes recently developed transgenic sugarcane (“oilcane”) bagasse for chemical-free coproduction of high-value bioproducts, i.e., furfurals, HMF, acetic acid, cellulosic sugars, and vegetative lipids. Hydrothermal pretreatment was optimized at 210 °C for 5 min to coproduce 6.91%, 2.67%, 5.07%, 2.42% and 37.82% (w/w) furfurals, HMF, acetic acid, vegetative lipids, and cellulosic sugars, respectively from lignocellulosic biomass. Additionally, nanofiltration system in-series was successfully established to recover sugars, furfurals, HMF, and acetic acid from the pretreatment liquor. 1st nanofiltration with Duracid NF membrane rejected ∼99% sugars. Concentrated sugars with significantly reduced inhibitory products were obtained in retentate for fermentation. 2nd nanofiltration with NF90 membrane used permeate of 1st nanofiltration as feed and rejected ∼ 86% furfurals. The work demonstrates the feasibility of coproducing and recovering multiple biochemicals from lignocellulosic biomass.

Biomass Analytics↗
DOE OSTI2025

Solvent Transport in Disordered and Dynamic Membrane Pores: Implications for Reverse Osmosis and Nanofiltration Membranes

Pressure-driven separations with nanoporous membranes, such as reverse osmosis and nanofiltration, play a vital role in addressing water scarcity and enabling resource recovery. Understanding water or solvent transport in membrane pores is essential for advancing membrane separation technologies. A key question in transport modeling is to establish a relationship between solvent permeability and membrane porous structure properties, such as porosity or pore size. The nano- and subnanometer pores in polymeric membranes such as reverse osmosis and nanofiltration membranes are highly tortuous and dynamically connected, which challenges the conventional methods of transport modeling. This study addresses this challenge by developing a theoretical framework to describe solvent transport through membranes with dynamic and disordered porous structure. Specifically, we propose a lattice model to describe the pore network, while preserving the viscous nature of solvent permeation. We further establish a relationship between solvent permeability and membrane porosity or pore size, which is validated by molecular dynamics simulations and experimental data. By integrating this relationship into the solution-friction model, we define pore connectivity and local friction coefficient to quantify the impact of pore structure on solvent permeability. Our analysis highlights the dominant influence of pore connectivity on the permeability of reverse osmosis and nanofiltration membranes, particularly when the pore size approaches the dimensions of solvent molecules. Overall, this study provides critical insights into water and solvent transport mechanisms in nanoporous membranes, opening the door for strategies to substantially enhance membrane performance.

membranes↗
DOE OSTI2024

Rejection of malathion by nanofiltration and reverse osmosis membranes exposed to foulant and two clean-in-place procedures

This research tested the treatment efficacy of an Energy Savings Nanofiltration 1 Low Fouling (ESNA 1-LF) nanofiltration (NF) and an Energy Saving Polyamide 2 (ESPA2) reverse osmosis (RO) membrane for removing malathion from water. Both membranes are of composite polyamide construction. The study included measuring malathion rejection using both pristine membranes and membranes exposed to a simulated secondary wastewater effluent foulant before and after two types of clean-in-place procedures. Across all conditions studied, malathion rejection ranged from 84 to 95% for the ESNA1-LF NF membrane and 77 to 94% for the ESPA2 RO membrane. Contact angle measurements were also collected for each membrane exposure condition. While the contact angle measurements indicated changes to the hydrophobicity of the selective layer of the membranes, they did not correlate to changes in the performance of malathion rejection. As expected, it was observed that malathion rejection improved with the introduction of foulant. Also, the clean-in-place procedures helped restore flux while maintaining malathion rejection.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

Cross-flow separation characteristics and piloting of graphene oxide nanofiltration membrane sheets and tubes for kraft black liquor concentration

Dewatering of weak black liquor (WBL) in the kraft cycle by evaporation is highly energy intensive. Membranes are an attractive alternative for energy-efficient dewatering, but existing commercial polymeric or ceramic membranes are either degraded in BL or have high capital costs. Our recent works have demonstrated the engineering of graphene oxide (GO) nanofiltration membranes, their stability and promising performance in BL conditions, and preliminary scale-up into sheets and tubes. Here, we describe in detail the separation characteristics of GO membrane sheets and tubes under real BL conditions and crossflow operation. Recycle-mode piloting of a GO tubular membrane showed average “production flux” of 16 L/m2/h (LMH) and high rejections of lignin (98.3%), total solids (66%), and total organic carbon (83%), with no signs of irreversible fouling identified. A corresponding GO sheet membrane produced an average flux of ~25 LMH and maintained high lignin rejection of ~97% during a slipstream pilot at a kraft mill site using WBL with ~16 wt% total solids (TS). Finally, we piloted a Dow/DuPont XUS1808 polyamide composite reverse osmosis (RO) membrane for last-mile processing of the GO nanofiltration membrane permeate. The RO membrane showed a steady state flux of 19 LMH at 65 bar and produced ~0.02 wt% TS water product, which is highly suitable for reuse in pulp washing operations in the kraft process. The results have strong positive implications for the industrial application of GO membranes in BL concentration and other related applications.

Materials Science↗
NASA NTRS1995

On-line removal of volatile fatty acids from CELSS anaerobic bioreactor via nanofiltration

The CELSS (controlled ecological life support system) resource recovery system, which is a waste processing system, uses aerobic and anaerobic bioreactors to recover plants nutrients and secondary foods from the inedible biomass. The anaerobic degradation of the inedible biomass by means of culture of rumen bacteria,generates organic compounds such as volatile fatty acids (acetic, propionic, butyric, VFA) and ammonia. The presence of VFA in the bioreactor medium at fairly low concentrations decreases the microbial population's metabolic reactions due to end-product inhibition. Technologies to remove VFA continuously from the bioreactor are of high interest. Several candidate technologies were analyzed, such as organic solvent liquid-liquid extraction, adsorption and/or ion exchange, dialysis, electrodialysis, and pressure driven membrane separation processes. The proposed technique for the on-line removal of VFA from the anaerobic bioreactor was a nanofiltration membrane recycle bioreactor. In order to establish the nanofiltration process performance variables before coupling it to the bioreactor, a series of experiments were carried out using a 10,000 MWCO tubular ceramic membrane module. The variables studied were the bioreactor slurry permeation characteristics, such as, the permeate flux, VFA and the nutrient removal rates as a function of applied transmembrane pressure, fluid recirculation velocity, suspended matter concentration, and process operating time. Results indicate that the permeate flux, VFA and nutrients removal rates are directly proportional to the fluid recirculation velocity in the range between 0.6 to 1.0 m/s, applied pressure when these are low than 1.5 bar, and inversely proportional to the total suspended solids concentration in the range between 23,466 to 34,880. At applied pressure higher than 1.5 bar the flux is not more linearly dependent due to concentration polarization and fouling effects over the membrange surface. It was also found that the permeate flux declines rapidly during the first 5 to 8 hours, and then levels off with a diminishing rate of flux decay.

Colon, Guillermo↗
DOE OSTI2025

Nanofiltration Membranes for Li + /Mg 2+ Separation: Materials and Mechanisms

Nanofiltration (NF) membranes have garnered significant interest for Li + /Mg 2+ separation, a crucial step in lithium extraction from brines. The state-of-the-art commercial LiNE-XD membrane exhibits a Li + /Mg 2+ separation factor (SF Li/Mg ) of 42 at pH 3.3, due to the positive charges on the membrane surface and its strong size-sieving ability. Membranes with higher separation factors at a broad pH range are being pursued to improve separation efficiency. This work aims to provide a timely and comprehensive assessment of advanced NF membranes with superior Li + /Mg 2+ separation properties, as well as their structure and property relationships for designing next-generation membranes. We describe transport mechanisms for ions in NF membranes and discuss governing parameters and models employed to quantify the Li + /Mg 2+ separation. High-performance membrane materials are exhaustively introduced, including commercial and modified polyamides, two-dimensional materials, metal–organic frameworks, crown ethers, and their blends. Finally, we critically compare these membranes in an upper bound plot and highlight the opportunities and challenges of NF membranes for practical Li + /Mg 2+ separations.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2025

Valorizing Hydrothermal liquefaction aqueous phase via nanofiltration: Enhancing biocrude production from algal biomass

The hydrothermal liquefaction aqueous phase (HTL-AP), a nutrient- and carbon-rich waste byproduct of the HTL process, can be recirculated to enhance biocrude production efficiency. To avoid dilution of the HTL feedstock and reduced fuel quality associated with recirculating untreated HTL-AP, this study investigated nanofiltration to concentrate organic compounds and separate nutrients from HTL-AP of three algal biomass sources: an algal wastewater treatment system and two from harmful algal blooms in lakes. Up to 99% of the organics were recovered in the concentrated HTL-AP (retentate), and significant increases in both permeate flux and permeation of nitrogenous compounds were achieved by increasing HTL-AP temperature to 45 °C and pH to 11. Recirculating the concentrated HTL-AP increased biocrude yield by 70%-116% and reduced biocrude nitrogen content by up to 12%. The carbon and energy capture in the biocrude also increased by 66% and 68%, respectively.

09 BIOMASS FUELS↗
DOE OSTI2023

Highly tunable structure-by-design polymer brush membranes for organic solvent nanofiltration

Synthetic polymeric nanofiltration membrane processes offer an alternate low-energy option to energy-intensive distillation to fractionate similar size organic solvents for chemical, petroleum, food and biotechnology industries. Here, in this study, we synthesize and test a new class of structure-by-design hydrophilic polymeric brush membranes, that address the limitations of commercial polymer membranes, are tunable and exhibit commercially relevant filtration performance. Because these brush membranes are grafted by Single Electron Transfer-Living Radical Polymerization (SET-LRP) and replace statistically random phase inversion or interfacial polymerization used for synthesizing commercial polymer membranes, their porous structure can be remodeled by varying their morphology and chemistry. We graft hydroxyethyl methacrylate (HEMA) brush structures with short and long crosslinkers, demonstrate two competing phenomena - pore stiffening and opening - and obtain high selectivity at reasonable permeability for commercially relevant methanol/toluene separation. This new class of stable, tunable, and scalable membranes offers exciting opportunities to reduce energy for separation of organic solvents.

42 ENGINEERING↗
DOE OSTI2025

Engineering surface charges of nanofiltration membranes to maximize Li + /Mg 2+ separation properties

Polyamide-based nanofiltration (NF) membranes are attractive for Li + /Mg 2+ separation for lithium recovery from salt brine (containing mainly Mg 2+ ). However, Li + and Mg 2+ have similar hydration radii, resulting in a low separation factor (SF Li/Mg ). Herein, we demonstrate that SF Li/Mg can be significantly enhanced by optimizing the membrane surface positive charges. This results in an unexpected maximum SF Li/Mg at a solution pH slightly below its isoelectric point (IEP). Specifically, NF270 membrane was surface-grafted with 2-(methacryloyloxy)ethyltrimethylammonium chloride (META) or polyethylenimine (PEI) using bio-adhesive dopamine, forming a thin, stable, charged layer (20–40 nm) on the surface. The effects of solution pH and surface modification on the surface zeta potential (ZP) and single- and mixed-salt Li + /Mg 2+ separation properties are thoroughly investigated. For example, the META grafting increases the ZP from 9.2 to 16 mV and SF Li/Mg by 130 % from 35 to 80 at pH 4, superior to the state-of-the-art commercial NF membranes. Furthermore, this surface modification occurs at ≈22 °C in aqueous solutions and can be utilized to enhance commercial modules for practical applications.

Li+/Mg2+ separation↗
DOE OSTI2024

A lyotropic liquid crystal-templated nanofiltration membrane with thermo- and pH-responsive 3D transport pathway

We produce controlled nanostructured membranes from cross-linking of self-assembled diacrylated poloxamers. At sufficiently high concentrations, poloxamers form lyotropic liquid crystals (LLCs), such as lamellar (L α ), cubic packing of spherical micelles, and hexagonal packing of rod-like micelles in water (H 1 ). We use the H 1 phase as a template to produce orderly packed nanofibrous membranes. The obtained membrane has a continuous 3D transport pathway and can alter its nanofiltration (NF) properties in response to changes in temperature and pH. The formulation includes Pluronic P84-diacrylate (P84DA), a thermoresponsive component that acts as both macromer and structure-directing amphiphile. P84DA facilitates changes in membrane pore size with temperature due to its thermoresponsiveness when it is in contact with water. Furthermore, the precursor contains acrylic acid (AAc) as the charged component, which upon copolymerization with P84DA, not only enables ion separation through Donnan exclusion but also imparts pH-responsive behavior for the separation of ionic species. The membrane performance is studied and compared with a commercial NF membrane (NF270). We show that the synthesized NF membrane has separation properties adjustable with temperature and pH with exceptional resistance to fouling by various solutes due to its highly hydrophilic surface. Furthermore, the membrane shows an outstanding sulfate over chloride ion selectivity, which is a requirement for salt fractionation applications. Deducted from separate experiments, the ideal chloride/sulfate selectivity for magnesium cation is about 2.38 at low ionic strengths. This study is done on a model system to show the capability of incorporating pH-responsiveness in LLC templated membranes, in which the pH-responsive range can be designed by changing the charged groups of comonomer in the formulation.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Bicarbonate-Carbonate Selectivity through Nanofiltration for Direct Air Capture of Carbon Dioxide

Direct air capture (DAC) of carbon dioxide is one approach among many proposed that is capable of offsetting hard-to-avoid emissions. In previous work, we developed the alkalinity concentration swing (ACS) method, which is driven through concentrating an alkaline solution that has been loaded with atmospheric CO 2 by desalination technologies, such as reverse osmosis or capacitive deionization. Though the ACS is promising in terms of energy usage and implementation, its absorption rate and water requirements are infeasible for a large-scale DAC process. Here, we propose an improvement on the ACS, the bicarbonate-enriched alkalinity concentration swing (BE-ACS), which selects bicarbonate ions from a stream of aqueous alkaline solution that has absorbed atmospheric CO 2 . The bicarbonate-rich stream is then concentrated, which greatly increases its CO 2 partial pressure, and then CO 2 is extracted from solution. We experimentally investigate the use of pressure-driven nanofiltration (NF) membrane-based separation to select bicarbonate ions over carbonate ions. We screen commercial membranes and select one high-performance membrane for detailed studies, quantifying its bicarbonate-carbonate selectivity factor and bicarbonate-passage factor. Feed pH, the combined concentration of aqueous CO 2 , bicarbonate, and carbonate species (or dissolved inorganic carbon), alkalinity, and permeation flux are systematically varied to study NF separation properties. We find that the selectivity factor, which exceeds 30 times in certain regimes, increases with higher feed pH and higher alkalinity. Lastly, the performance metrics of the selected NF membrane are input into a theoretical BE-ACS cycle analysis, and the required energy input and cycle capacity output are evaluated. Ideal cycle energy is found to be as low as around 250 kJ/mol, with opportunities identified for further decreases through process engineering and forward osmosis energy recovery.

animal feed↗
DOE OSTI2024

Self-assembled nanofiltration membranes with thermo- and pH-responsive behavior

We produce controlled nanostructured membranes from cross-linking of self-assembled diacrylated poloxamers. At sufficiently high concentrations, poloxamers form lyotropic liquid crystals (LLCs), such as lamellar (L α ), cubic packing of spherical micelles, and hexagonal packing of rod-like micelles in water (H 1 ). We use the H 1 phase as a template to produce orderly packed nanofibrous membranes. The obtained membrane has a continuous 3D transport pathway and can alter its nanofiltration (NF) properties in response to changes in temperature and pH. The formulation includes Pluronic P84-diacrylate (P84DA), a thermoresponsive component that acts as both macromer and structure-directing amphiphile. P84DA facilitates changes in membrane pore size with temperature due to its thermoresponsiveness when it is in contact with water. Furthermore, the precursor contains acrylic acid (AAc) as the charged component, which upon copolymerization with P84DA, not only enables ion separation through Donnan exclusion but also imparts pH-responsive behavior for the separation of ionic species. The membrane performance is studied and compared with a commercial NF membrane (NF270). We show that the synthesized NF membrane has separation properties adjustable with temperature and pH with exceptional resistance to fouling by various solutes due to its highly hydrophilic surface. Furthermore, the membrane shows an outstanding sulfate over chloride ion selectivity, which is a requirement for salt fractionation applications. Deducted from separate experiments, the ideal chloride/sulfate selectivity for magnesium cation is about 2.38 at low ionic strengths. This study is done on a model system to show the capability of incorporating pH-responsiveness in LLC templated membranes, in which the pH-responsive range can be designed by changing the charged groups of comonomer in the formulation.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Scalable aqueous-phase fabrication of reduced graphene oxide nanofiltration membranes by an integrated roll-to-roll (R2R) process

Economic fractionation of multicomponent biomass-derived streams is a key challenge in biobased fuels and chemicals production. Kraft black liquor (BL) is generated at ~1 billion tons/yr globally from biomass pulping and contains ~15wt% total solids including lignin, hemicellulose fragments, and inorganics. Membrane-based BL concentration is attractive but challenged by low solute rejections and poor stability in BL, which combines alkaline pH (~13), high dissolved solids content (15+ wt%) and high temperature (70–85°C). Here we discuss the scaled fabrication and characterization of reduced graphene oxide (rGO) nanofiltration membranes by slot die coating on a roll-to-roll (R2R) with integrated vacuum filtration. Here, we obtain high-quality 90×30 cm rGO membranes (referred to as “R2R-rGO membranes” in this work) with ~100 nm average thickness supported on porous poly(ethersulfone) (PES) sheets, and an effective area of 2700cm 2 . We present characterizations of their microstructure and uniformity as mapped over large areas by scanning electron microscopy (SEM), ellipsometry, adhesion test and X-ray photoelectron spectroscopy (XPS). The constructed ellipsometry model for the rGO membrane/PES substrate composite was successfully applied to 48 different locations of the R2R-rGO membranes. The R2R-rGO membranes showed >98% lignin rejection with a steady state flux of ~12 LMH at 50bar in a 15.7wt% total solids (TS) kraft BL stream at 72°C and 2–3 gal/min crossflow rates. Slot die coating on a R2R platform with integrated vacuum filtration can enable rapid fabrication of high-quality GO membranes at scale without organic solvents or volatile organic compounds.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2024

Calcium-organic matter fouling in nanofiltration: Synchrotron-based X-ray fluorescence and absorption near-edge structure spectroscopy for speciation

Calcium (Ca)-enhanced organic matter (OM) fouling of nanofiltration (NF) membranes leads to reduced flux during desalination and requires frequent cleaning. Fouling mechanisms are not fully understood, which limits the development of targeted fouling control methods. This study employed synchrotron-based X-ray fluorescence (XRF) and X-ray absorption near-edge structure (XANES) spectroscopy to quantify the spatial distribution and mass of Ca deposition as well as changes in the Ca coordination environment characteristic of specific fouling mechanisms, respectively. Bench-scale filtration experiments were performed using feed solutions containing Ca and ten different types of organic matter (OM), as well as the common scalants, calcium carbonate (CaCO 3 ) and calcium sulfate (CaSO 4 ). Osmotic backwash (OB) was performed at regular intervals for fouling control. Ca-OM aggregation resulted in greater flux decline and lower flux recovery during OB than Ca conditioning of membranes followed by filtration of feed solution with OM. Linear combination fitting (LCF) of XANES absorption spectra from fouled membranes indicated that Ca-OM aggregation preferentially occurred for OM types that exhibited both high carboxylic group and negative charge density. Consequently, these OM types exhibited greater deposition of Ca and TOC on the membrane surface when compared to other OM types. For the coexistence of scalants and OM, Ca speciation within the fouling layer was characteristic of both Ca bound to the membrane (i.e. potential bridging, charge screening) as well as Ca-OM aggregation and deposition mechanisms, while a range of crystal polymorphs were observed to occur simultaneously. XRF and XANES represent powerful tools for the elucidation of NF fouling mechanisms by quantification of Ca deposition as well as Ca speciation. Fouling control methods should target OM types with high carboxyl group density and negative charge to neutralize or eliminate interactions with Ca.

42 ENGINEERING↗
DOE OSTI2024

The physical basis for solvent flow in organic solvent nanofiltration

Organic solvent nanofiltration (OSN) is an emerging membrane technology that could revolutionize chemical separations in numerous vital industries. Despite its significance, there remains a lack of fundamental understanding of solvent transport mechanisms in OSN membranes. Here, we use an extended Flory-Rehner theory, nonequilibrium molecular dynamic simulations, and organic solvent transport experiments to demonstrate that solvent flow in OSN membranes is driven by a pressure gradient. We show that solvent molecules migrate as clusters through interconnected pathways within the membrane pore structure, challenging the widely accepted diffusion-based view of solvent transport in OSN. We further reveal that solvent permeance is dependent on solvent affinity to the OSN membrane, which, in turn, controls the membrane pore structure. Our fundamental insights lay the scientific groundwork for the development of next-generation OSN membranes.

42 ENGINEERING↗
NASA NTRS2007

Bench-Top Antigen Detection Technique that Utilizes Nanofiltration and Fluorescent Dyes which Emit and Absorb Light in the Near Infrared

This article discusses the development of a bench-top technique to detect antigens in fluids. The technique involves the use of near infrared NIR fluorescent dyes conjugated to antibodies, centrifugation, nanofilters, and spectrometry. The system used to detect the antigens utilizes a spectrometer, fiber optic cables, NIR laser, and laptop computer thus making it portable and ideally suited for desk top analysis. Using IgM as an antigen and the secondary antibody, anti-IgM conjugated to the near infrared dye, IRDye (trademark) 800, for detection, we show that nanofiltration can efficiently and specifically separate antibody-antigen complexes in solution and that the complexes can be detected by a spectrometer and software using NIR laser excitation at 778 nm and NIR dye offset emission at 804 nm. The peak power detected at 778 nm for the excitation emission and at 804 nm for the offset emission is 879 pW (-60.06 dBm) and 35.7 pW (-74.5 dBm), respectively.

Varaljay-Spence, Vanessa A.↗