Nanocomposite DNA hydrogels emerging as programmable and bioinstructive materials systems

Nanocomposite DNA hydrogels with temperature sensitivity

We present and discuss several modern optical methods based on elastic light scattering (ELS), along with their technical features and applications in biomedicine and life sciences. In particular, we review some ELS experiments at the single-cell level and explore new directions of applications. Due to recent developments in experimental systems (as shown in the literature), ELS lends itself to useful applications in the life sciences. Of the developed methods, we cover elastic scattering spectroscopy, optical tweezer-assisted measurement, goniometers, Fourier transform light scattering (FTLS), and microscopic methods. FTLS significantly extends the potential analysis of single cells by allowing monitoring of dynamical changes at the single-cell level. The main aim of our review is to demonstrate developments in the experimental investigation of ELS in single cells including issues related to theoretical “representations” and modeling of biological systems (cells, cellular systems, tissues, and so on). Goniometric measurements of ELS from optically trapped single cells are shown and the importance of the experimental verification of theoretical models of ELS in the context of biomedical applications is discussed.

Extracted nanocellulose from natural resources commonly requires modification before it is used as an effective nanofiller. In the present study, through an enzymatic polymerization of α-d-glucose 1-phosphate from the primer 2-(glucosyloxy)ethyl methacrylate (GEMA), a novel type of two-dimensional methacrylate-containing cellulose nanosheets (CNS) with a thickness of about 6 nm, named as GEMA-CNS, was directly synthesized under a mild condition by a "bottom-up" method. The structure and morphology of GEMA-CNS were characterized by 1H-nuclear magnetic resonance (NMR), matrix-assisted laser desorption/ionization time-of-flight mass spectra (MALDI-TOF MS), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), and atomic force microscopy (AFM). Afterward, the obtained GEMA-CNS was covalently incorporated into poly(ethylene glycol) matrix through thiol-ene Michael addition, fabricating a series of GEMA-CNS-based nanocomposite hydrogels. The addition of GEMA-CNS effectively improved the mechanical strength and altered the internal network structures of hydrogels; additionally, the swelling/biodegradation behaviors of gels in phosphate buffer saline (pH 7.4) at 37 °C were affected to some degree. This species of property-tunable hydrogels with GEMA-CNS dosage demonstrates potential applications in tissue engineering. The current presentation opens a new road for direct enzymatic preparation of reactive nanocellulose and its novel applications in nanocomposite materials.

Thermally activated delayed fluorescence (TADF) is a temperature-dependent luminescence mechanism that allows the harvesting of both singlet and triplet excitons for fluorescence emission. Consequently, TADF-active compounds exhibit excellent photophysical properties, such as high luminescence efficiencies and long excited-state lifetimes. In recent times, TADF materials have found widespread applications in material and life science, most prominently in organic light-emitting diodes (OLEDs). Many design strategies for TADF emitters have emerged, amongst which the use of transition metal complexes constitutes an appealing approach. In this chapter, the theoretical background of the TADF phenomenon is discussed, different types of metal-based TADF emitters are introduced, selected case studies are highlighted, and an overview is given of the many applications of TADF materials in light-driven systems.

The use of light ions for microscopy and tomography is illustrated by a variety of recent applications in materials and life sciences at the Leipzig high-energy ion-nanoprobe LIPSION with a short comparison to other microscopic techniques. The versatility of ion techniques is exemplified by Rutherford backscattering spectrometry maps of thin films of solar cell materials, particle induced X-ray emission maps of manganese in ancient human bones, particle induced X-ray emission on single aerosol particles with μm size, and scanning transmission ion microscopy and tomography on pigs knee cartilage. Finally, the design of a single ion single living cell bombardment facility is sketched for studies of the cellular response and microdosimetry.

A 3D hydrogel based on chitosan and carbon dots for sensitive fluorescence detection of microRNA-21 in breast cancer cells

Recently, micro-electro-mechanical-systems (MEMS) technology and micromachining techniques have enabled miniaturization of biomedical devices and systems. Not only do these techniques facilitate the development of miniaturized instrumentation for biomedical analysis, but they also open a new era for integration of microdevices for performing accurate and sensitive diagnostic assays. A so-called “micro-total-analysis-system”, which integrates sample pretreatment, transport, reaction, and detection on a small chip in an automatic format, can be realized by combining functional microfluidic components manufactured by specific MEMS technologies. Among the promising applications using microfluidic technologies, nucleic acid-based detection has shown considerable potential recently. For instance, micro-polymerase chain reaction chips for rapid DNA amplification have attracted considerable interest. In addition, microfluidic devices for rapid sample pretreatment prior to nucleic acid-based detection have also achieved significant progress in the recent years. In this review paper, microfluidic systems for sample preparation, nucleic acid amplification and detection for fast diagnosis will be reviewed. These microfluidic devices and systems have several advantages over their large-scale counterparts, including lower sample/reagent consumption, lower power consumption, compact size, faster analysis, and lower per unit cost. The development of these microfluidic devices and systems may provide a revolutionary platform technology for fast sample pretreatment and accurate, sensitive diagnosis.

This Frontiers review analyzes the rapidly growing microfluidic strategies that have been employed in attempts to create physio relevant 'organ-on-chip' models using primary tissue removed from a body (human or animal). Tissue harvested immediately from an organism, and cultured under artificial conditions is referred to as ex vivo tissue. The use of primary (organotypic) tissue offers unique benefits over traditional cell culture experiments, and microfluidic technology can be used to further exploit these advantages. Defining the utility of particular models, determining necessary constituents for acceptable modeling of in vivo physiology, and describing the role of microfluidic systems in tissue modeling processes is paramount to the future of organotypic models ex vivo. Virtually all tissues within the body are characterized by a large diversity of cellular composition, morphology, and blood supply (e.g., nutrient needs including oxygen). Microfluidic technology can provide a means to help maintain tissue in more physiologically relevant environments, for tissue relevant time-frames (e.g., matching the natural rates of cell turnover), and at in vivo oxygen tensions that can be controlled within modern microfluidic culture systems. Models for ex vivo tissues continue to emerge and grow in efficacy as mimics of in vivo physiology. This review addresses developments in microfluidic devices for the study of tissues ex vivo that can serve as an important bridge to translational value.

Microfluidics is a promising and upcoming technology for diagnostics and drug developments. With huge potential in bringing a revolution in biotechnology, there is going to be a big commercial demand for microfluidic systems in life science applications. The function of microfluidic system highly depends on the precise control of tiny fluid volumes by micropumps, and hence, design, fabrication, and integration of micropumps are the key components in microfluidic systems. Though the development of micropumps has been paid attention for the past two decades, it is still a great challenge in realizing a reliable and improved performance of a micropump. This chapter discusses a detailed study on various pumping mechanisms of micropumps reported with a perspective on the scope for manufacturing. The issues and challenges in commercialization will be discussed, and the possible solutions to overcome will also be highlighted.

Focus on nanotechnology, lasers, and imaging

In 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.

Os autores externos submeteram sua publicação para apresentação de trabalho no evento “International Symposium on Immunobiologicals”, que foi coordenado e organizado pelo Instituto de Tecnologia em Imunobiológicos (Bio-Manguinhos), da Fundação Oswaldo Cruz.

ConspectusMolecular chirality defines the non-superimposability of three-dimensional molecules onto their mirror images. Due to the often drastically distinct biological effects exhibited by enantiomers, the synthesis of enantiopure small organic molecules remains a topic of persistent research interest. Molecular chirality is commonly divided into point, axial, planar, and helical types based on stereogenic elements. In contrast, inherently chiral molecules form a unique category that lacks these conventional chiral elements. Their chirality results from curvature introduced into a planar structure without a perpendicular symmetry plane in two dimensions. A prominent example of this category is inherently chiral macrocycles (ICMs), which possess chirality solely due to their macrocyclic, nonplanar structure. Conversely, ring-opening of an ICM yields an achiral linear molecule. It is noteworthy that while the synthesis and application of conventional chiral molecules have reached a high degree of sophistication, the chemistry of ICMs remains largely unexplored, primarily due to the significant challenges in obtaining them in highly enantioenriched forms. Resolution of racemic samples using analytical HPLC with columns coated with a chiral stationary phase is the most frequently used method to obtain small amounts of enantiomers.Since the beginning of my independent research career in 2018, driven by my long-standing interest in molecular chirality, our group has engaged in the chemistry of inherently chiral macrocyclic compounds, a research field largely neglected and underexplored by mainstream scientists. From the viewpoint of the structure and the diversity of molecular chirality, it is fascinating to generate a chiral molecular space consisting of almost limitless macrocyclic entities that do not rely on chiral building blocks. Beyond their conceivable applications as conventional chiral compounds, ICMs hold significant potential to offer unique advantages and open new opportunities in areas such as molecular recognition, asymmetric catalysis, and functional materials. Over the past six years, to address the limited availability of highly enantiopure ICMs, we have successfully developed three primary strategies: (1) de novo synthesis of ICMs from linear precursors; (2) desymmetrization of symmetric macrocycles; and (3) dynamic kinetic resolution (DKR) of racemic macrocycles, which enables efficient construction of enantiomerically enriched ICMs. With inherently chiral compounds in hand, we are free to systematically study their structure and properties. We have demonstrated that ICMs provide an extraordinary platform for the fabrication of chiroptical materials and chiral catalysts in supramolecular catalysis. In this Account, we summarize our efforts in exploring the chemistry of ICMs, with a focus on the catalytic enantioselective synthesis, their structural characteristics, the assignment of the absolute configuration, and their unique chiroptical properties and potential applications in supramolecular catalysis. We hope the advancement of synthetic methodology can open doors to the rational design and precise construction of novel ICMs. The easy availability of enantioenriched ICMs could then inspire scientists to explore their applications in chemistry, materials, and life sciences.

The addition of surface functional groups to multi-walled carbon nanotubes (MWCNTs) expands their application in engineering, materials, and life science. In the study, we explored the antifungal activities of MWCNTs with different surface groups against an important plant pathogenic fungi Fusarium graminearum. All of the OH-, COOH-, and NH2-modified MWCNTs showed enhanced inhibition in spore elongation and germination than the pristine MWCNTs. The length of spores decreased by almost a half from 54.5 μm to 28.3, 27.4, and 29.5 μm, after being treated with 500 μg·mL−1 MWCNTs-COOH, MWCNTs-OH, and MWCNTs-NH2 separately. Furthermore, the spore germination was remarkably inhibited by surface-modified MWCNTs, and the germination rate was only about 18.2%, three times lower than pristine MWCNTs. The possible antifungal mechanism of MWCNTs is also discussed. Given the superior antifungal activity of surface modified MWCNTs and the fact that MWCNTs can be mass-produced with facile surface modification at low cost, it is expected that this carbon nanomaterial may find important applications in plant protection.

Several problems are encountered in modeling and processing of many life science applications such like tissue engineering, bioacoustics, and food processing detection. Recently, various image processing techniques have been developed in an attempt to solve these problems. Due to the rapid advance and high number of researches included in such field, there is always a room for improvement. In this work, advanced image processing approaches are presented and applied to different life science applications. The first approach utilizes image processing in the generation of micro-scaffolds for tissue engineering modeling. Furthermore, a spectrogram enhancement approach is developed to improve the pattern detection of weevils existence in grain storage, based on their detected and identified sounds. Finally, a novel edge detection method applied on intramuscular fat recognition is presented based on the energy and skewness as two smoothed versions of the meat image. Results, in comparison to experimental data, offer a maximum error of 7.81% in the specified detection process. 1. Material and Method 1.1 Generation of micro-porous approach The difficulty of modeling such complex micro-structures always lies in retrieving the geometry into the solver as edges. Edge detection algorithms are based upon highlighting discontinuities in images and were first developed for satellite images. The technique has become well-known and was further developed and widely used for other image processing applications. During the conventional detection procedures, usually all the image size is processed, which leads to redundant calculations of areas containing no edge information. In this study a redundant avoiding algorithm is developed which searches for the threshold value in the image and then propagates around it in a 2-D lattice in eight directions figure 1.1, until an edge is hit. Figure 1.1 The scanning procedure for gradient changes propagates in an eight directional lattice until an edge is hit 1.2 Spectrogram enhancement in bioacoustics This approach is based on detection of the sound pattern edges in the crest factor image, as shown in figure 1.2 and 1.3, which behaves as a smoothed version of the spectrogram image and avoids the use of edge detectors prior smoothing filters and their scaling constraints. Figure 1.2 Spectrogram with 40 dB limited dynamic range Figure 1.3 Crest factor distributions (left), the scaled crest factor image of the spectrogram (right). 1.3 Edge detection for intramuscular fat recognition A novel edge detection method applied on intramuscular fat is presented based on the energy and skewness as two smoothed versions of the meat image, as shown in the flow chart given in figure 1.4. Figure 1.4 flow chart edge detection 2. Results 2.1.Generation of micro-porous Approach The conventional approach for edge detection is based upon either thresholding the first derivative (gradient) of the image or locating zero crossings of its second derivative (Laplacian).The sample used, figure 2.1, for this simulation was of size 3 mm, 350 μm and 350 μm in z-direction, x-direction and y-direction, respectively. The geometry was uploaded on the solver by collective segmenting and edge detection techniques. The method has proven time saving and as well enables the possibility of parallel processing of the image, as each threshold value can be scanned and dealt with independently. After the predictions of the edges, the 2-d binary edge images are assembled forming a 3-D binary file of the scaffolds figure 2.1. Figure 2.1 From the micro-CT images 430 hundred 2-D binary edge images are assembled forming a 3-D binary file of the scaffolds 2.2.Spectrogram enhancement in bioacoustics The spectrogram enhancement approach is compared to other enhancement approaches, including multiband spectral subtraction and wavelet packet decomposition, for different structure bioacoustics calls including bats (ultrasound range) and birds (acoustic range), with additive white Gaussian noise added across a range of signal to noise ratios. Results measured subjectively and objectively, indicate that the proposed method is promising for efficiently spectrogram enhancing while preserving its temporal and spectral accuracy, as shown in figure 2.2. Figure 2.2 (a) One of Sitta Canadensis bird calls at SNR = 20 dB, and its enhanced spectrogram by (b) BP, (c) MBSS, (d) WF, (e) WPD, and (f) the proposed method approaches. 2.3.Edge detection for intramuscular fat recognition The generation of micro-scaffolds approach is applied on a sample meat image, which is scanned line by line and every noticeable variance in the color values or the grey levels is captured and the local thresholds values are estimated according to the highest drop gradient value. The local threshold values are averaged to estimate the global threshold for the whole image, as shown in figure 2.1. Figure 2.3 an image for a meat with fat (a), the x y scan of the image which does not show all the fat details (b) and the lattice scan of the image showing more details of the fat, as circled by red (c). For intramuscular fat, the developed edge detection approach is used to predict the fat content in marbled meat images, as shown in figure 2.3. Figure 2.4 (a) original marbled meat images, (b) edges images using the proposed method (c) detected fat regions, and (d) the percentage of fat content Conclusion As observed in the different approaches there is always a room for improvement that minimize the error observed in the specified detection process. The methods have proven time saving and as well enables the possibility of parallel processing of the image that leads to a more efficient performance highly desirable for industrial applications.