Life Science Applications Research Articles

Synthesis and Characterization of Carbon Microbeads.

We report a microfluidic-based droplet generation platform for synthesizing micron-sized porous carbon microspheres. The setup employs carbon materials such as graphite, carbon nanotubes, graphene, fullerenes, and carbon black as starting materials. Custom composition, structure, and function are achieved through combinations of carbon materials, cross-linkers, and additives along with variations in process parameters. Carbon materials can be assembled into spheres with a mean diameter of units to hundreds of μm with relatively tight size distribution (<25% RSD). Pore structure and size (tens to hundreds of angstrom) can be modulated by incorporating porogen/coporogen dilutants during synthesis. The microbeads have excellent mechanical stability with an elastic modulus of hundreds of MPa. They can sustain high dynamic fluid flow pressures of up to 9000 psi. This work lays the foundation for synthesizing novel tailorable and customizable carbon microbeads. It opens avenues for applying these novel materials for composite and additive manufacturing, energy, life science, and biomedical applications.

(Invited) Multimodality Sensing and Actuation Using Nanocarbons

My team’s efforts are focused on the development and engineering of nanocarbons-based flexible platforms to interrogate and affect the properties of cells and tissue, with a specific goal to understand signal transduction (chemical or electrical) in tissue or complex 3D cellular assemblies. Our highly flexible bottom-up nanomaterials synthesis capabilities allow us to form unique hybrid-nanomaterials that can be used in various input/output bioelectrical interfaces, i.e., bioelectrical platforms for chemical and physical sensing and actuation. We have developed several approaches for monitoring (and affecting) the complex signal transduction in 3D cellular assemblies toward an organ-on-an-electronic-chip (organ-on-e-chip) platform for tissue maturation and disease progression investigations. Utilizing graphene, a two-dimensional (2D) atomically thin carbon allotrope, we can simultaneously record the intracellular electrical activity of multiple excitable cells with ultra-microelectrodes that can be as small as an axon (ca. 2µm). The outstanding electrochemical properties of the synthesized hybrid-nanomaterials allow us to develop highly efficient catalysts, that can be deployed as electrical sensors and (chemical) actuators. We demonstrated sensors capable of exploring brain chemistry and sensors/actuators that are deployed in a large volumetric muscle loss animal model. Finally, using the unique optical properties of nanocarbons in the form of graphene-based hybrid-nanomaterials and 2D nanocarbides (MXene), we have formed remote, non-genetic bioelectrical interfaces with excitable cells and modulated cellular and network activity with low needed energy and high precision. In summary, the exceptional synthetic control and flexible assembly of nanomaterials provide powerful tools for fundamental studies and applications in life science and potentially seamlessly merge nanomaterials-based platforms with cells, fusing nonliving and living systems together.

Scanning Local Redox on 10 Micron Spots on a Monolith Electrode to Quantify Multiple Analytes at 10 Attomolar Sensitivity with Dynamic Range of Seven Orders of Magnitude

Electrochemical transduction is arguably the most prolific and impactful method to sense chemicals and biochemicals. For example, electrochemical methods have the distinct advantage to quantitatively measure nucleic acid (NA) sequences at a limit of quantification (LOQ) of 10 attomolars and high sequence specificity. The sensitivity and dynamic range significantly surpasses optical/spectroscopic, gravimetric, and electronic transduction methods. However, electrochemical sensing cannot be easily multiplexed. Only one analyte per electrode can be measured. Furthermore, the electrode size, i.e., the sensor area, for reasonable redox current, is typically, at least 1 mm2 for small analyte concentration.A fully automated instrument, called the Scanning Electrometer for Electrical Double-layer (SEED), will be described that addresses the abovementioned limitations. SEED, based on differential optics, quantitatively measures electrochemical process by changes in the electrical double-layer (EDL) and the surface during electrochemical process. The instrument can be operated in three modes: (a) reflectivity; (b) interferometry; (c) spectroscopy. The instrument can be toggled between the three modes without moving the sample or realigning the optics. The three modes measure the structural change at the surface, change in charge state of the EDL, and change in the molecule’s electronic structure due to the electrochemical process.The principle will be described with following applications in material science, sensing and life science: (i) miRNA profiling at LOQ of 10 attomolar with dynamic range of seven orders of magnitude; (ii) single base mutation in NA sequence; (iii) heavy metal ion detection from ppt to ppb levels; (iv) spectroscopic measurement during redox on graphene; (v) Langmuir adsorption of ions on Au electrode; and (vi) direct measurement of potential of zero charge (PZC). Figure 1

Colloidal Manipulation through Plasmonic and Non‐plasmonic Laser‐Assisted Heating

AbstractIn spite of the long‐term awareness of the conversion of light to heat even in materials with low absorption coefficient via the photothermal effect and consequent usage of the effect to evaluate thermo‐optic properties of the materials, only recently has the thermal field created via photon‐to‐phonon conversion been exploited for manipulation of colloidal objects as well as living cells. As compared to conventional direct photon‐assisted manipulation via optical tweezers, the optothermal manipulation technique employs much lower optical source power and can manipulate particles over a long range. In this review, the working mechanisms, concepts, and applications of a series of recently established optothermal techniques are discussed for the manipulation of diverse species including micro/nanoparticles, biological cells, molecules, and micelles in various fluidic environments. The physical mechanism of the optical manipulation that relies on the coordinated action of thermal convection, Marangoni convection, thermophoresis, thermoelectricity, depletion attraction, and thermo‐osmotic flow is discussed in detail. With their low‐power operation, diverse functionalities, and simple optics employed, optothermal manipulation techniques are increasingly finding a wide range of applications in colloidal science, life sciences, materials science, and nanoscience, as well as in the developments of colloidal functional devices and nanomedicine.

Fragment Screening and Fast Micromolar Detection on a Benchtop NMR Spectrometer Boosted by Photoinduced Hyperpolarization.

Fragment-based drug design is a well-established strategy for rational drug design, with nuclear magnetic resonance (NMR) on high-field spectrometers as the method of reference for screening and hit validation. However, high-field NMR spectrometers are not only expensive, but require specialized maintenance, dedicated space, and depend on liquid helium cooling which became critical over the recurring global helium shortages. We propose an alternative to high-field NMR screening by applying the recently developed approach of fragment screening by photoinduced hyperpolarized NMR on a cryogen-free 80 MHz benchtop NMR spectrometer yielding signal enhancements of up to three orders in magnitude. It is demonstrated that it is possible to discover new hits and kick-off drug design using a benchtop NMR spectrometer at low micromolar concentrations of both protein and ligand. The approach presented performs at higher speed than state-of-the-art high-field NMR approaches while exhibiting a limit of detection in the nanomolar range. Photoinduced hyperpolarization is known to be inexpensive and simple to be implemented, which aligns greatly with the philosophy of benchtop NMR spectrometers. These findings open the way for the use of benchtop NMR in near-physiological conditions for drug design and further life science applications.

Fragment‐Screening und schnelle mikromolare Detektion mit einem Benchtop‐NMR‐Spektrometer ermöglicht durch photoinduzierte Hyperpolarisation

AbstractFragmentbasiertes Wirkstoffdesign ist eine gut etablierte Strategie für rationales Arzneimitteldesign, wobei die Kernspinresonanzspektroskopie (NMR) auf Hochfeldspektrometern als Referenzmethode für das Screening und die Hit‐Validierung dient. Hochfeld‐NMR‐Spektrometer sind jedoch nicht nur teuer, sondern erfordern auch eine spezielle Wartung, einen speziellen Raum und sind auf die Kühlung mit flüssigem Helium angewiesen, was angesichts der wiederkehrenden weltweiten Heliumknappheit kritisch geworden ist. Wir schlagen eine Alternative zum Hochfeld‐NMR‐Screening vor, indem wir den kürzlich entwickelten Ansatz des Fragment‐Screenings durch photoinduzierte hyperpolarisierte NMR auf einem kryogenfreien 80‐MHz‐Benchtop‐NMR‐Spektrometer anwenden, der Signalverstärkungen von bis zu drei Größenordnungen ermöglicht. Es wird gezeigt, dass es möglich ist, mit einem Benchtop‐NMR‐Spektrometer bei niedrigen mikromolaren Konzentrationen sowohl von Proteinen als auch von Liganden neue Hits zu entdecken und die Entwicklung von Medikamenten einzuleiten. Der vorgestellte Ansatz arbeitet mit höherer Geschwindigkeit als moderne Hochfeld‐NMR‐Ansätze und weist eine Nachweisgrenze im nanomolaren Bereich auf. Die photoinduzierte Hyperpolarisation ist bekanntlich kostengünstig und einfach zu implementieren, was der Philosophie von Benchtop‐NMR‐Spektrometern sehr entgegenkommt. Diese Ergebnisse ebnen den Weg für den Einsatz von Benchtop‐NMRunter nahezu physiologischen Bedingungen für die Entwicklung von Arzneimitteln und weitere Life‐Science‐Anwendungen.

Bioelectric Interface Technologies in Cells and Organoids

AbstractThe past two decades have witnessed breakthroughs in cellular‐scale bioelectronics and their widespread applications in life sciences, creating many powerful platforms for studying organisms directly and efficiently. These advanced devices can integrate seamlessly and intimately onto/into target cells and organoids, providing unprecedented functions and revolutionary capabilities. Bioelectronics with nanostructured designs are developed to allow for long‐term, stable monitoring of electrophysiological activities. This review summarizes nanostructured bioelectronics for cell electrophysiology recording, emphasizing the crucial roles of structural designs on functions and capabilities, e.g., intracellular access, high‐density multiplexed recording, multifunctional interfaces and the conformability to curvy biological shapes. Finally, the remaining challenges and opportunities in nanostructured bioelectronics are identified, and perspectives on the future developments toward their practical applications are provided.

Rapid and sensitive detection of endogenous HClO in living cells and zebrafish using a phenothiazine-based fluorescent probe

Hypochlorous acid (HClO) is a reactive oxygen species (ROS) that plays a critical role in numerous pathological and physiological processes. Abnormal concentrations of HClO in vivo have been closely linked to many diseases, including inflammatory disorders and cancer. In this work, an on-off fluorescent probe PTZ based on phenothiazine was synthesized for specific detection of HClO. PTZ demonstrated excellent selectivity, biocompatibility, rapid response, pH stability, and low limits of detection (5.2 nM). Furthermore, PTZ can detect both exogenous and endogenous HClO rapidly in living cells and zebrafish, which provides it with broad potential applications in life sciences.

Selective expansion of target cells using the Enrich TROVO platform.

Enriching target cell clones from diverse cell populations is vital formany life science applications. We have developed a novel method to rapidly and efficiently purify specific clonal cell populations from a larger, heterogeneous group using theEnrich TroVo system (Enrich Biosystems Inc., CT, USA). This system takes advantage of microfabrication and optical technologies by utilizing small hydrogel wells to separate desired cell populations and an innovative patching technique to selectively eliminate undesired cells. This method allows the isolation and growth of desired cells with minimal impact on their viability and proliferation. We successfully isolated and expanded clonal cell populations of desired cells using two model cells. Compared with fluorescence-activated cell sorting, Enrich TroVo system offers a promising alternative for isolating of sensitive, adherent cells, that is, patient-derived cells.

Quartz tuning fork (QTF) coating enhanced Mid-Infrared laser Induced-Thermoacoustic spectroscopy (LITES) for human exhaled methane detection

Human exhaled methane (CH4) has essential significance in detecting intestinal flora. In this study, a high-precision quartz tuning fork (QTF) based light-induced thermoelastic spectroscopy (LITES) system was developed, a mid-infrared interband cascade laser (ICL) and a QTF detector coated with polydimethylsiloxane (PDMS) and reduced graphene oxide (rGO) were employed for the CH4 detection. Experimental results indicate that the composite coating resulted in a 3-fold increase in 2f signal amplitude and signal-to-noise ratio (SNR), when compared to the bare QTF detector. The system has achieved a minimum detection limit (MDL) of 58.65 ppbv (part per billion volume) and a normalized noise equivalent absorption coefficient (NNEA) of 2.069 × 10−10 cm−1·W·Hz−1/2, Allan deviation analysis indicates that the optimal measurement accuracy is 36.85 ppbv. 24 healthy college students and 10 overweight/obese students were recruited to measure the CH4 concentration in the exhaled breath. The results show that exhaled CH4 concentrations of healthy individuals range from 0.5 to 3 ppmv (part per million volume), with slightly higher levels in males than females, and higher levels in the obese individuals than those in the normal individuals. The mid-infrared LITES CH4 measurement system holds promise as a new non-invasive method for assessing human metabolic states, with potential applications in medical and life sciences.

2D CdPS3-based versatile superionic conductors

Ion transport in nanochannels is crucial for applications in life science, filtration, and energy storage. However, multivalent ion transport is more difficult than the monovalent analogues due to the steric effect and stronger interactions with channel walls, and the ion mobility decreases significantly as temperature decreases. Although many kinds of solid ionic conductors (SICs) have been developed, they can attain practically useful conductivities (0.01 S cm−1) only for monovalent ions above 0 °C. Here, we report a class of versatile superionic conductors, monolayer CdPS3 nanosheets-based membranes intercalated with diverse cations with a high density up to ∼2 nm−2. They exhibit unexpectedly similar superhigh ion conductivities for monovalent (K+, Na+, Li+) and multivalent ions (Ca2+, Mg2+, Al3+), ∼0.01 to 0.8 S cm−1 in the temperature range of −30 ‒ 90 °C, which are one to two orders of magnitude higher than those of the corresponding best SICs. We reveal that the high conductivity originates from the concerted movement of high-density cations in the well-ordered nanochannels with high mobility and low energy barrier. Our work opens an avenue for designing superionic conductors that can conduct various cations and provides possibilities for discovering unusual nanofluidic phenomena in nanocapillaries.

Cobalt Ferrite Nanoparticles Capped with Perchloric Acid for Life-Science Application

Among the modern oncological therapies, one of the most promising is based on tumor hyperthermia with magnetic nanoparticles resulting from the crystallization of iron and cobalt oxides. We synthesized core–shell magnetic nanoparticles of perchlorate-CoxFe3−xO4 (x = 0; 0.5; 1.0) via the co-precipitation method and stabilized them in aqueous suspensions. Fine granulation of the dispersed ferrophase was revealed by Transmission Electron Microscopy and Dynamical Light Scattering, with FTIR data detailing the surface-interaction phenomena. X-ray diffractometry revealed specific crystallization features of inverse spinel lattice, providing crystallite size and lattice parameters dependent on the cobalt content. The results of the Vibrating Sample Magnetometry investigations indicated that cobalt doping has reduced the magnetic core size and increased the nanoparticle dimension, which could be the result of crystallization defects at the nanoparticle surface related to the presence of cobalt ions. A mathematical model was applied with a focus on the quantitative description of the temperature distribution around magnetic nanoparticles. Further development of our research will consider new cobalt ferrite nanoparticles with new cobalt contents and different organic coatings to contribute to their biocompatibility and stability in aqueous suspensions, as required by administration in living organisms.

Rezension zu: Enzyme Engineering: Selective Catalysts for Applications in Biotechnology, Organic Chemistry, and Life Science

Rezension zu: Enzyme Engineering: Selective Catalysts for Applications in Biotechnology, Organic Chemistry, and Life Science

3D Aerosol Jet® printing for microstructuring: Advantages and limitations

Aerosol Jet&amp;reg; printing (AJ&amp;reg;P) is a direct writing printing technology that deposits functional aerosolized solutions on free-form substrates. Its potential has been widely adopted for two-dimensional (2D) microscale constructs in printed electronics (PE), and it is rapidly growing toward surface structuring and biological interfaces. However, limited research has been devoted to its exploitation as a three-dimensional (3D) printing technique. In this study, we investigated AJ&amp;reg;P capabilities for 3D microstructuring of three inks, as well as their advantages and limitations by employing three proposed 3D AJ&amp;reg;P strategies (continuous jet deposition, layer-by-layer, and point-wise). In particular, 3D microstructures of increasing complexity based on silver nanoparticle (AgNPs)-, poly(3,4-ethylenedioxythiophene)polystyrene sulfonate (PEDOT:PSS)-, and collagen-based inks were investigated at various aspect ratios and resolutions. Biocompatibility assays were also performed to evaluate inks cytotoxicity effects on selected cellular lineages, including neuronal and osteoblast cell lines. Results show the possibility to print not only arrays of micropillars of different aspect ratios (AgNPs-ARs ~ 20, PEDOT:PSS-ARs ~ 4.5, collagen-ARs ~ 2.5), but also dense and complex (yet low reproducible) leaf- or flake-like structures (especially with the AgNPs-based ink), and lattice units (collagen-based ink). Specifically, this study demonstrates that the fabrication of 3D AJ&amp;reg;-printed microstructures is possible only with a specific set of printing parameters, and firmly depends on the ink (co-)solvents fast-drying phenomena during the printing process. Furthermore, the data concerning inks biocompatibility revealed high cytotoxicity levels for the AgNPs-based ink, while low ones for the PEDOT:PSS and the collagen-based inks. In conclusion, the paper provides general guidelines with respect to ink development and print strategies for 3D AJ&amp;reg;P microstructuring, opening its adoption in a vast range of applications in life science (tissue engineering, bioelectronic interfaces), electronics, and micromanufacturing.

Glycerol Flow through a Shielded Coil Induces Aggregation and Activity Enhancement of Horseradish Peroxidase

Glycerol has found its applications as a heat-transfer fluid in heat exchangers, and as a component of functional liquids in biosensor analysis. Flowing non-aqueous fluids are known to be able to induce electromagnetic fields due to the triboelectric effect. These triboelectrically generated electromagnetic fields can affect biological macromolecules. Horseradish peroxidase (HRP) is widely employed as a convenient model object for studying how external electric, magnetic, and electromagnetic fields affect enzymes. Herein, we have studied whether the flow of glycerol in a ground-shielded cylindrical coil affects the HRP enzyme incubated at a 2 cm distance near the coil’s side. Atomic force microscopy (AFM) has been employed in order to study the effect of glycerol flow on HRP at the nanoscale. An increased aggregation of HRP on mica has been observed after the incubation of the enzyme near the coil. Moreover, the enzymatic activity of HRP has also been affected. The results reported that their application can be found in biotechnology, food technology and life sciences applications, considering the development of triboelectric generators, enzyme-based biosensors and bioreactors with surface-immobilized enzymes. Our work can also be of interest for scientists studying triboelectric phenomena, representing one more step toward understanding the mechanism of the indirect action of the flow of a dielectric liquid on biological macromolecules.

Magnetic Dendritic Polymer Nanospheres for High-Performance Separation of Histidine-Rich Proteins.

Magnetic nanospheres are becoming a promising platform for a wide range of applications in pharmacy, life science, and immunodiagnostics due to their high surface area, ease of synthesis and manipulation, fast separation, good biocompatibility, and recyclable performance. In this work, an innovative and efficient method is developed by in situ reducing and growing Ni(OH)2 for the preparation of dendritic mesoporous nanocomposites of silica@Fe3O4/tannic acid@nickel hydroxide (dSiO2@Fe3O4/TA@Ni(OH)2). The flower-like nanospheres have good magnetic response, large surface area, and high histidine-rich protein (His-protein) purification performance. The dSiO2@Fe3O4/TA@Ni(OH)2 nanospheres were synthesized on the basis of a φ(NaSal/CTAB) of 1/1 and a mass of ferrous chloride tetrahydrate of 0.3 g, resulting in a saturation magnetization value of 48.21 emu/g, which means it can be collected within ∼1 min using a magnetic stand. Also, the BET test showed that the surface area is 92.47 m2/g and the pore size is ∼3.9 nm for dSiO2@Fe3O4/TA@Ni(OH)2 nanocomposites. Notably, the nickel hydroxide with unique flower-like structural features enables the combination of a large number of Ni2+ ions and His-proteins for high performance. The isolation and purification experiments of the synthesized dSiO2@Fe3O4/TA@Ni(OH)2 were performed by separating His-proteins from a matrix composed of bovine hemoglobin (BHb), bovine serum albumin (BSA), and lysozyme (LYZ). The result showed that the nanospheres have a high combination capacity of ∼1880 mg/g in a rapid equilibrium time of 20 min, which was selective for the adsorption of BHb. In addition, the stability and recyclability of BHb are 80% after seven cycles. Furthermore, the nanospheres were also used to isolate His-proteins from fetal bovine serum, proving its utility. Therefore, the strategy of separating and purifying His-proteins using dSiO2@Fe3O4/TA@Ni(OH)2 nanospheres is promising for practical applications.

Ultraviolet-curable Material with High Fluorine Content for Biomimetic Functional Structures Achieved by Nanoimprint Lithography with Gas-permeable Template for Life Science and Electronic Applications

Ultraviolet-curable Material with High Fluorine Content for Biomimetic Functional Structures Achieved by Nanoimprint Lithography with Gas-permeable Template for Life Science and Electronic Applications

TEMPO-Oxidized Cellulose Nanofibril Films Incorporating Graphene Oxide Nanofillers.

To design a new system of novel TEMPO-oxidized cellulose nanofibrils (TOCNs)/graphene oxide (GO) composite, 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-mediated oxidation was utilized. For the better dispersion of GO into the matrix of nanofibrillated cellulose (NFC), a unique process combining high-intensity homogenization and ultrasonication was adopted with varying degrees of oxidation and GO percent loadings (0.4 to 2.0 wt%). Despite the presence of carboxylate groups and GO, the X-ray diffraction test showed that the crystallinity of the bio-nanocomposite was not altered. In contrast, scanning electron microscopy showed a significant morphological difference in their layers. The thermal stability of the TOCN/GO composite shifted to a lower temperature upon oxidation, and dynamic mechanical analysis signified strong intermolecular interactions with the improvement in Young's storage modulus and tensile strength. Fourier transform infrared spectroscopy was employed to observe the hydrogen bonds between GO and the cellulosic polymer matrix. The oxygen permeability of the TOCN/GO composite decreased, while the water vapor permeability was not significantly affected by the reinforcement with GO. Still, oxidation enhanced the barrier properties. Ultimately, the newly fabricated TOCN/GO composite through high-intensity homogenization and ultrasonification can be utilized in a wide range of life science applications, such as the biomaterial, food, packaging, and medical industries.

Advancements in portable instruments based on affinity-capture-migration and affinity-capture-separation for use in clinical testing and life science applications

The shift from testing at centralized diagnostic laboratories to remote locations is being driven by the development of point-of-care (POC) instruments and represents a transformative moment in medicine. POC instruments address the need for rapid results that can inform faster therapeutic decisions and interventions. These instruments are especially valuable in the field, such as in an ambulance, or in remote and rural locations. The development of telehealth, enabled by advancements in digital technologies like smartphones and cloud computing, is also aiding in this evolution, allowing medical professionals to provide care remotely, potentially reducing healthcare costs and improving patient longevity. One notable POC device is the lateral flow immunoassay (LFIA), which played a major role in addressing the COVID-19 pandemic due to its ease of use, rapid analysis time, and low cost. However, LFIA tests exhibit relatively low analytical sensitivity and provide semi-quantitative information, indicating either a positive, negative, or inconclusive result, which can be attributed to its one-dimensional format. Immunoaffinity capillary electrophoresis (IACE), on the other hand, offers a two-dimensional format that includes an affinity-capture step of one or more matrix constituents followed by release and electrophoretic separation. The method provides greater analytical sensitivity, and quantitative information, thereby reducing the rate of false positives, false negatives, and inconclusive results. Combining LFIA and IACE technologies can thus provide an effective and economical solution for screening, confirming results, and monitoring patient progress, representing a key strategy in advancing diagnostics in healthcare.

Near-Infrared Fluorescence Enhancement by Deuteration of Phthalocyanine.

Organic compounds with near-IR (NIR) fluorescence have many potential applications in materials and life sciences, but the much weaker intensity of fluorescence in the NIR region than in the UV-visible region is a major obstacle. Herein we show that deuteration of phthalocyanines, a representative class of organic NIR dyes, increases both the fluorescence quantum yield and the fluorescence lifetime compared with non-deuterated phthalocyanines.