Zero-length crosslinking procedure with the use of active esters

Possibility and challenge of plant-derived ferritin cages encapsulated polyphenols in the precise nutrition field

Polyphenols have attracted extensive attention due to their rich functional activities, such as antioxidant, anti-inflammatory and anti-tumor. However, the low solubility and poor stability limit their bioavailability and functional activities. Plant-derived ferritin cages have a unique hollow cage structure that can embed polyphenols to improve their unfavorable properties. Therefore, it is essential to adequately elaborate and summarize plant-derived ferritin cages to maximize their potential benefits in nutritional interventions. This review focuses on the fundamental properties of plant-derived ferritin cages, including the preparation process, purification technology, identification methods, and structural and functional properties. The relevant research on ferritin cages in polyphenol delivery has been summarized, including the delivery of water/lipid soluble polyphenols, modification of ferritin cages, and the interaction between polyphenols and ferritin cages. The research progress, shortcomings and prospects of plant-derived ferritin cages in precise nutrition are introduced. In addition, the relevant research on ferritin in immune response and protein engineering is also discussed to provide the theoretical basis for applying plant-derived ferritin cages in many frontier fields.

On-site sensing for aflatoxicosis poisoning via ultraviolet excitable aptasensor based on fluorinated ethylene propylene strip: a promising forensic tool

The environmental contamination by extremophile Aspergillus species, i.e., Aflatoxin B1, is hardly controllable in Southeast Asia and Sub-Saharan Africa, which lack handling resources and controlled storage facilities. Acute aflatoxicosis poisoning from aflatoxin-prone dietary staples could cause acute hepatic necrosis, acute liver failure, and death. Here, as the cheaper, more straightforward, and facile on-site diagnostic kit is needed, we report an ultraviolet-excitable optical aptasensor based on a fluorinated ethylene propylene film strip. Molecular dynamics on the aptamer.AFB1 complex revealed that the AFB1 to the aptamer increases the overall structural stability, suggesting that the aptamer design is suitable for the intended application. Under various influencing factors, the proposed label-free strategy offers a fast 20-min on-site fabrication simplicity and 19-day shelf-life. The one-pot incubation provides an alternative to catalytic detection and exhibited 4 times reusability. The recovery of crude brown sugar, processed peanuts, and long-grain rice were 102.74 ± 0.41 (n = 3), 86.90 ± 3.38 (n = 3), and 98.50 ± 0.42 (n = 3), comparable to High-Performance Liquid Chromatography-Photodiode Array Detector results. This study is novel owing to the peculiar UV-active spectrum fingerprint and the convenient use of hydrophobic film strips that could promote breakthrough innovations and new frontiers for on-site/forensic detection of environmental pollutants.

Amidation of arabinoglucuronoxylans to modulate their flow behavior

Arabinoglucuronoxylans obtained from the exudate of Cercidium praecox (Brea gum) were subjected to an amidation reaction to modulate their flow behavior to obtain a product with similar behavior to gum Arabic. The amidation reaction of the uronic acids present in this exudate was studied using the 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) and N-hydroxysuccinimide (NHS) system with the aim of maximizing product yield and minimizing by-product. An analysis of the significant factors involved in the reaction was carried out and a response surface methodology was conducted to optimize the stoichiometry of the reagents used. It was possible to obtain models for predicting the degree of amidation (DA) of arabinoglucuronoxylans and the formation of by-products. The formation of a secondary product derived from the amino acid β-alanine which has not been reported previously in the reaction with polysaccharides, was described. The flow behavior of an amidated product (DA = 52 %) was determined, showing a pseudoplastic behavior and a decreased Newtonian viscosity (η0 = 36.2 Pa s) at the lowest shear rate range with respect to native product solution (η0 = 115 Pa s). Amidated arabinoglucuronoxylans had a flow behavior more similar to that of gum Arabic.

Ultrasound-Based Micro-/Nanosystems for Biomedical Applications

Due to the intrinsic non-invasive nature, cost-effectiveness, high safety, and real-time capabilities, besides diagnostic imaging, ultrasound as a typical mechanical wave has been extensively developed as a physical tool for versatile biomedical applications. Especially, the prosperity of nanotechnology and nanomedicine invigorates the landscape of ultrasound-based medicine. The unprecedented surge in research enthusiasm and dedicated efforts have led to a mass of multifunctional micro-/nanosystems being applied in ultrasound biomedicine, facilitating precise diagnosis, effective treatment, and personalized theranostics. The effective deployment of versatile ultrasound-based micro-/nanosystems in biomedical applications is rooted in a profound understanding of the relationship among composition, structure, property, bioactivity, application, and performance. In this comprehensive review, we elaborate on the general principles regarding the design, synthesis, functionalization, and optimization of ultrasound-based micro-/nanosystems for abundant biomedical applications. In particular, recent advancements in ultrasound-based micro-/nanosystems for diagnostic imaging are meticulously summarized. Furthermore, we systematically elucidate state-of-the-art studies concerning recent progress in ultrasound-based micro-/nanosystems for therapeutic applications targeting various pathological abnormalities including cancer, bacterial infection, brain diseases, cardiovascular diseases, and metabolic diseases. Finally, we conclude and provide an outlook on this research field with an in-depth discussion of the challenges faced and future developments for further extensive clinical translation and application.

Antibacterial polylysine-containing hydrogels for hemostatic and wound healing applications: preparation methods, current advances and future perspectives

The treatment of various types of wounds such as dermal wounds, multidrug resistant bacteria-infected wounds, and chronic diabetic wounds is one of the critical challenges facing healthcare systems. Delayed wound healing can impose a remarkable burden on patients and health care professionals. In this case, given their unique three-dimensional porous structure, biocompatibility, high hydrophilicity, capability to provide a moist environment while absorbing wound exudate, permeability to both gas and oxygen, and tunable mechanical properties, hydrogels with antibacterial function are one of the most promising candidates for wound healing applications. Polylysine is a cationic polymer with the advantages of inherent antibacterial properties, biodegradability, and biocompatibility. Therefore, its utilization to engineer antibacterial hydrogels for accelerating wound healing is of great interest. In this review, we initially discuss polylysine properties, and then focus on the most recent advances in polylysine-containing hydrogels (since 2016) prepared using various chemical and physical crosslinking methods for hemostasis and wound healing applications. Finally, the challenges and future directions in the engineering of these antibacterial hydrogels for wound healing are discussed.

Advances in Bioreceptor Layer Engineering in Nanomaterial-based Sensing of Pseudomonas Aeruginosa and its Metabolites

Pseudomonas aeruginosa is a pathogen that infects wounds and burns and causes severe infections in immunocompromised humans. The high virulence, the rise of antibiotic-resistant strains, and the easy transmissibility of P. aeruginosa necessitate its fast detection and control. The gold standard for detecting P. aeruginosa, the plate culture method, though reliable, takes several days to complete. Therefore, developing accurate, rapid, and easy-to-use diagnostic tools for P. aeruginosa is highly desirable. Nanomaterial-based biosensors are at the forefront of detecting P. aeruginosa and its secondary metabolites. This review summarises the biorecognition elements, biomarkers, immobilisation strategies, and current state-of-the-art biosensors for P. aeruginosa. The review highlights the underlying principles of bioreceptor layer engineering and the design of optical, electrochemical, mass-based, and thermal biosensors based on nanomaterials. The advantages and disadvantages of these biosensors and their future point-of-care applications are also discussed. This review outlines significant advancements in biosensors and sensors for detecting P. aeruginosa and its metabolites. Research efforts have identified biorecognition elements specific and selective towards P. aeruginosa. The stability, ease of preparation, cost-effectiveness, and integration of these biorecognition elements onto transducers are pivotal for their application in biosensors and sensors. At the same time, when developing sensors for clinically significant analytes such as P. aeruginosa, virulence factors need to be addressed, such as the sensor's sensitivity, reliability, and response time in samples obtained from patients. The point-of-care applicability of the developed sensor may be an added advantage since it enables onsite determination. In this context, optical methods developed for P. aeruginosa offer promising potential.

Mn-Anti-CTLA4-CREKA-Sericin Nanotheragnostics for Enhanced Magnetic Resonance Imaging and Tumor Immunotherapy

The integration of magnetic resonance imaging (MRI), cGAS-STING, and anti-CTLA-4 (aCTLA-4) based immunotherapy offers new opportunities for tumor precision therapy. However, the precise delivery of aCTLA-4 and manganese (Mn), an activator of cGAS, to tumors remains a major challenge for enhanced MRI and active immunotherapy. Herein, a theragnostic nanosphere Mn-CREKA-aCTLA-4-SS (MCCS) is prepared by covalently assembling Mn2+, silk sericin (SS), pentapeptide CREKA, and aCTLA-4. MCCS are stable with an average size of 160 nm and is almost negatively charged or neutral at pH 5.5/7.4. T1-weighted images showed MCCS actively targeted tumors to improve the relaxation rate r1 and contrast time of MRI. This studies demonstrated MCCS raises reactive oxygen species levels, activates the cGAS-STING pathway, stimulates effectors CD8+ and CD80+ T cells, reduces regulatory T cell numbers, and increases IFN-γ and granzyme secretion, thereby inducing tumor cells autophagy and apoptosis in vitro and in vivo. Also, MCCS are biocompatible and biosafe. These studies show the great potential of Mn-/SS-based integrative material MCCS for precision and personalized tumor nanotheragnostics.

OpiCa1-PEG-PLGA nanomicelles antagonize acute heart failure induced by the cocktail of epinephrine and caffeine

Background

Reducing Ca2+ content in the sarcoplasmic reticulum (SR) through ryanodine receptors (RyRs) by calcin is a potential intervention strategy for the SR Ca2+ overload triggered by β-adrenergic stress in acute heart diseases.

Methods

OpiCal-PEG-PLGA nanomicelles were prepared by thin film dispersion, of which the antagonistic effects were observed using an acute heart failure model induced by epinephrine and caffeine in mice. In addition, cardiac targeting, self-stability as well as biotoxicity were determined.

Results

The synthesized OpiCa1-PEG-PLGA nanomicelles were elliptical with a particle size of 72.26 nm, a PDI value of 0.3, and a molecular weight of 10.39 kDa. The nanomicelles showed a significant antagonistic effect with 100 % survival rate to the death induced by epinephrine and caffeine, which was supported by echocardiography with significantly recovered heart rate, ejection fraction and left ventricular fractional shortening rate. The FITC labeled nanomicelles had a strong membrance penetrating capacity within 2 h and cardiac targeting within 12 h that was further confirmed by immunohistochemistry with a self-prepared OpiCa1 polyclonal antibody. Meanwhile, the nanomicelles can keep better stability and dispersibility in vitro at 4 °C rather than 20 °C or 37 °C, while maintain a low but stable plasma OpiCa1 concentration in vivo within 72 h. Finally, no obvious biotoxicities were observed by CCK-8, flow cytometry, H&E staining and blood biochemical examinations.

Conclusion

Our study also provide a novel nanodelivery pathway for targeting RyRs and antagonizing the SR Ca2+ disordered heart diseases by actively releasing SR Ca2+ through RyRs with calcin.

"Smart" Matrix Microneedle Patch Made of Self-Crosslinkable and Multifunctional Polymers for Delivering Insulin On-Demand

A transdermal patch that delivers insulin at high glucose concentrations can offer tremendous advantages to ease the concern of safety and improve the quality of life for people with diabetes. Herein, a novel self-crosslinkable and glucose-responsive polymer-based microneedle patch (MN) is designed to deliver insulin at hyperglycemia. The microneedle patch is made of hyaluronic acid polymers functionalized with dopamine and 4-amino-3-fluorophenylboronic acid (AFBA) that can be quickly crosslinked upon mixing of the polymer solutions in the absence of any chemicalcrosslinking agents or organic solvents. The catechol groups in the dopamine (DA) units form covalent crosslinkages among themselves by auto-oxidation and dynamic crosslink with phenylboronic acid (PBA) via complexation. The reversible crosslinkages between catechol and boronate decrease with increasing glucose concentration leading to higher swelling and faster insulin release at hyperglycemia as compared to euglycemia. Such superior glucose-responsive properties are demonstrated by in vitro analyses and in vivo efficacy studies. The hydrogel polymers also preserve native structure and bioactivity of insulin, attributable to the interaction of hyaluronic acid (HA) with insulin molecules, as revealed by experiments and molecular dynamics simulations. The simplicity in the design and fabrication process, and glucose-responsiveness in insulin delivery impart the matrix microneedle (mMN) patch great potential for clinical translation.

Bioinspired peptides designed for hair perming and dyeing with potential for repair

Cosmetics for perming hair are commonly used but have negative impacts on hair fibers. Repairing damaged hair with conditioners, hair oil, and hair masks can provide relief but cannot prevent injuries. Recent research has shown that proteins and amino acids can remodel hair's disulfide bonds. However, the permeation ability of proteins is limited, and amino acids may disrupt the secondary structure of hair keratins. Our study demonstrates that peptides can be safely, efficiently, and promisingly used for hair perming. A bioinspired peptide, PepACS (PepA-PepC-SPB), was designed through bioinformatics. It can interact with keratin's sulfhydryl group in situ to remodel disulfide bonds without affecting hair fiber's tensile properties. The potential of PepACS to repair cuticle injuries is also observed through scanning electron microscope visualization. Besides, linking PepACS with mCherry enables hair dyeing. This research suggests that biomaterials can be applied in the hair care industry. STATEMENT OF SIGNIFICANCE: Chemical perming products can have negative impacts on people's health and hair fibers, making it essential to explore alternative methods. Peptides treatment is a promising option, but synthesizing sulfur-rich short peptides for hair perming has not been demonstrated before. In this paper, we utilized bioinformatics to design bio-inspired peptides that can interact with hair keratins and form curled shapes. Our study demonstrates that bioinformatics tools can be utilized to design bioinspired peptides with unique functions. Sulfur-rich short peptides can be heterologously expressed with fusion strategies, and PepACS can securely bind hair fibers through disulfide bonds. Importantly, perming hair with 0.01% PepACS maintains the mechanical properties of hair, and dyeing hair with the fusion protein PepACS_mCh can be facilitated by ethanol. These findings suggest that the strategy of perming and dyeing hair through peptides is non-injurious, and the peptides used for repairing hair damage show tremendous potential.

An Integrated Approach to Improve the Assay Performance of Quantum Dot-Based Lateral Flow Immunoassays by Using Silver Deposition

Traditional quantum dot-based lateral flow immunoassay (QD-LFIA) is limited to signal loss in part by the blinking, photobleaching and oxidative quenching of QD probes. Inspired by the good application of silver deposition on QD surfaces in tissue imaging, and in the context of improving the assay performance without compromising the simplicity and practicality, we report that introducing the QD-silver combination to the LFIA system, has the advantages of accuracy improvement, signal enhancement and user friendliness promotion, but maintains the cost-effective property and commercial accessibility of QD-LFIA. The effect was shown by using CdSe/ZnS QD-LFIA coupled with anti-sodium pentachlorophenate antibody, which provided a 4-fold improvement in the signal, a 2.5-fold improvement in the detection limit and a zero false-negative rate for sodium pentachlorophenate analysis in chicken samples. The proposed LFIA integrates the possibilities of colorimetric and fluorometric detection with different detection limits (fluorometric at 10 ng/mL and colorimetric at 4 ng/mL) and with acceptable detection times (fluorometric at 12 min and colorimetric at 27 min). The current results indicate that this QD-silver combined LFIA is complementary to conventional fluorescence LFIA and could be an inexpensive, versatile, and sensitive alternative.

From Whispering Gallery Mode Resonators to Biochemical Sensors

Optical biosensors are frontrunners for the rapid and real-time detection of analytes, particularly for low concentrations. Among them, whispering gallery mode (WGM) resonators have recently attracted a growing focus due to their robust optomechanical features and high sensitivity, measuring down to single binding events in small volumes. In this review, we provide a broad overview of WGM sensors along with critical advice and additional "tips and tricks" to make them more accessible to both biochemical and optical communities. Their structures, fabrication methods, materials, and surface functionalization chemistries are discussed. We propose this reflection under a pedagogical approach to describe and explain these biochemical sensors with a particular focus on the most recent achievements in the field. In addition to highlighting the advantages of WGM sensors, we also discuss and suggest strategies to overcome their current limitations, leaving room for further development as practical tools in various applications. We aim to provide new insights and combine different knowledge and perspectives to advance the development of the next generation of WGM biosensors. With their unique advantages and compatibility with different sensing modalities, these biosensors have the potential to become major game changers for biomedical and environmental monitoring, among many other relevant target applications.

Paper-based electrochemical biosensors for the diagnosis of viral diseases

Paper-based electrochemical analytical devices (ePADs) have gained significant interest as promising analytical units in recent years because they can be fabricated in simple ways, are low-cost, portable, and disposable platforms that can be applied in various fields. In this sense, paper-based electrochemical biosensors are attractive analytical devices since they can promote diagnose several diseases and potentially allow decentralized analysis. Electrochemical biosensors are versatile, as the measured signal can be improved by using mainly molecular technologies and nanomaterials to attach biomolecules, resulting in an increase in their sensitivity and selectivity. Additionally, they can be implemented in microfluidic devices that drive and control the flow without external pumping and store reagents, and improve the mass transport of analytes, increasing sensor sensitivity. In this review, we focus on the recent developments in electrochemical paper-based devices for viruses' detection, including COVID-19, Dengue, Zika, Hepatitis, Ebola, AIDS, and Influenza, among others, which have caused impacts on people's health, especially in places with scarce resources. Also, we discuss the advantages and disadvantages of the main electrode's fabrication methods, device designs, and biomolecule immobilization strategies. Finally, the perspectives and challenges that need to be overcome to further advance paper-based electrochemical biosensors' applications are critically presented.

Strong, Chemically Stable, and Enzymatically On-Demand Detachable Hydrogel Adhesion Using Protein Crosslink

Achieving strong adhesion between hydrogels and diverse materials is greatly significant for emerging technologies yet remains challenging. Existing methods using non-covalent bonds have limited pH and ion stability, while those using covalent bonds typically lack on-demand detachment capability, limiting their applications. In this study, a general strategy of covalent bond-based and detachable adhesion by incorporating amine-rich proteins in various hydrogels and inducing the interfacial crosslinking of the hydrogels using a protein-crosslinking agent is demonstrated. The protein crosslink offers topological adhesion and can reach a strong adhesion energy of ≈750 J m^-2 . The chemistry of the adhesion is characterized and that the inclusion of proteins inside the hydrogels does not alter the hydrogels' properties is shown. The adhesion remains intact after treating the adhered hydrogels with various pH solutions and ions, even at an elevated temperature. The detachment is triggered by treating proteinase solution at the bonding front, causing the digestion of proteins, thus breaking up the interfacial crosslink network. In addition, that this approach can be used to adhere hydrogels to diverse dry surfaces, including glass, elastomers and plastics, is shown. The stable chemistry of protein crosslinks opens the door for various applications in a wide range of chemical environments.

Charge Transport across Proteins inside Proteins: Tunneling across Encapsulin Protein Cages and the Effect of Cargo Proteins

Charge transport across proteins can be surprisingly efficient over long distances-so-called long-range tunneling-but it is still unclear as to why and under which conditions (e.g., presence of co-factors, type of cargo) the long-range tunneling regime can be accessed. This paper describes molecular tunneling junctions based on an encapsulin (Enc), which is a large protein cage with a diameter of 24 nm that can be loaded with various types of (small) proteins, also referred to as "cargo". We demonstrate with dynamic light scattering, transmission electron microscopy, and atomic force microscopy that Enc, with and without cargo, can be made stable in solution and immobilized on metal electrodes without aggregation. We investigated the electronic properties of Enc in EGaIn-based tunnel junctions (EGaIn = eutectic alloy of Ga and In that is widely used to contact (bio)molecular monolayers) by measuring the current density for a large range of applied bias of ±2.5 V. The encapsulated cargo has an important effect on the electrical properties of the junctions. The measured current densities are higher for junctions with Enc loaded with redox-active cargo (ferritin-like protein) than those junctions without cargo or redox-inactive cargo (green fluorescent protein). These findings open the door to charge transport studies across complex biomolecular hierarchical structures.

Tailored Self-Assembled Monolayer using Chemical Coupling for Indium-Gallium-Zinc Oxide Thin-Film Transistors: Multifunctional Copper Diffusion Barrier

Controlling the contact properties of a copper (Cu) electrode is an important process for improving the performance of an amorphous indium-gallium-zinc oxide (a-IGZO) thin-film transistor (TFT) for high-speed applications, owing to the low resistance-capacitance product constant of Cu. One of the many challenges in Cu application to a-IGZO is inhibiting high diffusivity, which causes degradation in the performance of a-IGZO TFT by forming electron trap states. A self-assembled monolayer (SAM) can perfectly act as a Cu diffusion barrier (DB) and passivation layer that prevents moisture and oxygen, which can deteriorate the TFT on-off performance. However, traditional SAM materials have high contact resistance and low mechanical-adhesion properties. In this study, we demonstrate that tailoring the SAM using the chemical coupling method can enhance the electrical and mechanical properties of a-IGZO TFTs. The doping effects from the dipole moment of the tailored SAMs enhance the electrical properties of a-IGZO TFTs, resulting in a field-effect mobility of 13.87 cm²/V·s, an on-off ratio above 10⁷, and a low contact resistance of 612 Ω. Because of the high electrical performance of tailored SAMs, they function as a Cu DB and a passivation layer. Moreover, a selectively tailored functional group can improve the adhesion properties between Cu and a-IGZO. These multifunctionally tailored SAMs can be a promising candidate for a very thin Cu DB in future electronic technology.

Self-assembling nanofibrous bacteriophage microgels as sprayable antimicrobials targeting multidrug-resistant bacteria

Nanofilamentous bacteriophages (bacterial viruses) are biofunctional, self-propagating, and monodisperse natural building blocks for virus-built materials. Minifying phage-built materials to microscale offers the promise of expanding the range function for these biomaterials to sprays and colloidal bioassays/biosensors. Here, we crosslink half a million self-organized phages as the sole structural component to construct each soft microgel. Through an in-house developed, biologics-friendly, high-throughput template method, over 35,000 phage-built microgels are produced from every square centimetre of a peelable microporous film template, constituting a 13-billion phage community. The phage-exclusive microgels exhibit a self-organized, highly-aligned nanofibrous texture and tunable auto-fluorescence. Further preservation of antimicrobial activity was achieved by making hybrid protein-phage microgels. When loaded with potent virulent phages, these microgels effectively reduce heavy loads of multidrug-resistant Escherichia coli O157:H7 on food products, leading to up to 6 logs reduction in 9 hours and rendering food contaminant free.

A glass matrices-assisted quantum dots-based biosensor for selective capturing and detection of Escherichia coli

Bacterial contamination of water and food is a grave health concern rendering humans quite vulnerable to disease(s), and proving, at times, fatal too. Exploration of the novel diagnostic tools is, accordingly, highly called for to ensure rapid detection of the pathogenic bacteria, particularly Escherichia coli. The current manuscript, accordingly, reports the use of silane-functionalized glass matrices and antibody-conjugated cadmium telluride (CdTe) quantum dots (QDs) for efficient detection of E. coli. Synthesis of QDs (size: 5.4-6.8 nm) using mercaptopropionic acid (MPA) stabilizer yielded stable photoluminescence (∼62%), corroborating superior fluorescent characteristics. A test sample, when added to antibody-conjugated matrices, followed by antibody-conjugated CdTe-MPA QDs, formed a pathogen-antibody QDs complex. The latter, during confocal microscopy, demonstrated rapid detection of the selectively captured pathogenic bacteria (10 microorganism cells/10 μL) with enhanced sensitivity and specificity. The work, overall, encompasses establishment and design of an innovative detection platform in microbial diagnostics for rapid capturing of pathogens in water and food samples.

Crystal Contact Engineering for Enhanced Cross-Linking Efficiency of HheG Crystals

The generation of cross-linked enzyme crystals is a very attractive method for immobilization of enzymes displaying high crystalizability. However, the commonly used cross-linker glutaraldehyde is not always compatible with enzyme activity. Therefore, we previously reported the engineering of halohydrin dehalogenase HheG from Ilumatobacter coccineus to enable thiol-specific cross-linking during CLEC generation by insertion of cysteine residues in the crystal contact. To broaden the applicability of this approach, herein crystal contact engineering of HheG has been performed to incorporate additional lysine residues as defined cross-linking sites for CLEC generation. Using the primary amine-specific cross-linker dithiobis(succinimidyl propionate) (DSP), CLECs of HheG variant V46K were obtained that displayed a high gain in thermal stability compared to wild-type HheG, while using only a low cross-linker concentration. Moreover, respective V46K CLECs exhibited a 10 K higher reaction temperature optimum as well as significantly improved activity and stability at acidic pH and in the presence of organic co-solvents. Overall, our study demonstrates that lysine-specific cross-linkers can also be used as an alternative to glutaraldehyde for stable CLEC generation of halohydrin dehalogenases, and that cross-linking efficiency is significantly improved upon crystal contact engineering.

Fabrication Strategies Towards Hydrogels for Biomedical Application: Chemical and Mechanical Insights

This review aims at giving selected chemical and mechanical insights on design criteria that should be taken into account in hydrogel production for biomedical applications. Particular emphasis will be given to the chemical aspects involved in hydrogel design: macromer chemical composition, cross-linking strategies and chemistry towards "conventional" and smart/stimuli responsive hydrogels. Mechanical properties of hydrogels in view of regenerative medicine applications will also be considered.

A Comprehensive Review on Collagen Type I Development of Biomaterials for Tissue Engineering: From Biosynthesis to Bioscaffold

Collagen is the most abundant structural protein found in humans and mammals, particularly in the extracellular matrix (ECM). Its primary function is to hold the body together. The collagen superfamily of proteins includes over 20 types that have been identified. Yet, collagen type I is the major component in many tissues and can be extracted as a natural biomaterial for various medical and biological purposes. Collagen has multiple advantageous characteristics, including varied sources, biocompatibility, sustainability, low immunogenicity, porosity, and biodegradability. As such, collagen-type-I-based bioscaffolds have been widely used in tissue engineering. Biomaterials based on collagen type I can also be modified to improve their functions, such as by crosslinking to strengthen the mechanical property or adding biochemical factors to enhance their biological activity. This review discusses the complexities of collagen type I structure, biosynthesis, sources for collagen derivatives, methods of isolation and purification, physicochemical characteristics, and the current development of collagen-type-I-based scaffolds in tissue engineering applications. The advancement of additional novel tissue engineered bioproducts with refined techniques and continuous biomaterial augmentation is facilitated by understanding the conventional design and application of biomaterials based on collagen type I.

Is the small heat shock protein HSPB7 (cvHsp) a genuine actin-binding protein?

It is postulated that the small heat shock proteins directly interact with actin, affect formation and stabilize actin filaments. To verify this suggestion, we have analyzed interaction of recombinant human small heat shock protein HspB7 with skeletal muscle actin. In blot overlay HspB7 binds both G- and F-actin. The sites of interaction are located in the C-terminal large core domain of actin. In the course of ultracentrifugation F-actin and F-actin/tropomyosin complexes were pelleted and trapped HspB7. However, HspB7 pelleting was nonspecific and saturation was not achieved even at very high HspB7 concentration. HspB7 was unable to retard or prevent heat-induced F-actin aggregation. Native gel electrophoresis and chemical crosslinking failed to detect interaction of G-actin with HspB7, although both these methods clearly demonstrated formation of complexes formed by G-actin with DNAse I and cofilin-2. It is concluded that HspB7 is not a genuine actin-binding protein and its effect on actin filaments seems to be determined by interaction of HspB7 with minor regulatory proteins of actin filaments.

Functionalization strategies of polymeric nanoparticles for drug delivery in Alzheimer’s disease: Current trends and future perspectives

Alzheimer’s disease (AD), the most common form of dementia, is a progressive and multifactorial neurodegenerative disorder whose primary causes are mostly unknown. Due to the increase in life expectancy of world population, including developing countries, AD, whose incidence rises dramatically with age, is at the forefront among neurodegenerative diseases. Moreover, a definitive cure is not yet within reach, imposing substantial medical and public health burdens at every latitude. Therefore, the effort to devise novel and effective therapeutic strategies is still of paramount importance. Genetic, functional, structural and biochemical studies all indicate that new and efficacious drug delivery strategies interfere at different levels with various cellular and molecular targets. Over the last few decades, therapeutic development of nanomedicine at preclinical stage has shown to progress at a fast pace, thus paving the way for its potential impact on human health in improving prevention, diagnosis, and treatment of age-related neurodegenerative disorders, including AD. Clinical translation of nano-based therapeutics, despite current limitations, may present important advantages and innovation to be exploited in the neuroscience field as well. In this state-of-the-art review article, we present the most promising applications of polymeric nanoparticle-mediated drug delivery for bypassing the blood-brain barrier of AD preclinical models and boost pharmacological safety and efficacy. In particular, novel strategic chemical functionalization of polymeric nanocarriers that could be successfully employed for treating AD are thoroughly described. Emphasis is also placed on nanotheranostics as both potential therapeutic and diagnostic tool for targeted treatments. Our review highlights the emerging role of nanomedicine in the management of AD, providing the readers with an overview of the nanostrategies currently available to develop future therapeutic applications against this chronic neurodegenerative disease.

Platform for Active Vaccine Formulation Using a Two-Mode Enhancement Mechanism of Epitope Presentation by Pickering Emulsion

The efficiency of epitope-based vaccination (subunit vaccines) is tightly correlated with heterogeneity and the high density of epitope presentation, which maximizes the potential antigenic determinants. Here, we developed a two-mode platform for intensifying the epitope presentation of subunit vaccines. The two-mode epitope presentation enhancement includes a covalent attachment of high concentrations of SARS-CoV-2-S1 peptide epitope to the surface of virus-like-particles (VLPs) and the subsequent assembly of VLP/epitope conjugates on the oil droplet surface at an oil/water interface of an emulsion as Pickering stabilizers. The resultant emulsions were stable for weeks in ambient conditions, and our platform was challenged using the epitope of the SARS-CoV-2-S1 peptide that served as a model epitope in this study. In vivo assays showed that the αSARS-CoV-2-S1 immunoglobulin G (IgG) titers of the studied mouse antisera, developed against the SARS-CoV-2-S1 peptide under different epitope preparation conditions, showed an order of magnitude higher IgG titers in the studied VLP-based emulsions than epitopes dissolved in water and epitopes administered with an adjuvant, thereby confirming the efficacy of the formulation. This VLP-based Pickering emulsion platform is a fully synthetic approach that can be readily applied for vaccine development to a wide range of pathogens.

Fluorescence monitoring of the degradation evolution of aliphatic polyesters

To provide lifecycle monitoring for degradable polymers, we have proposed a three-dimensional fluorescence monitoring and quantification method to simultaneously study the thermal and photothermal degradation by combining the intrinsic conjugation and probe-labelled carboxyl of poly(butylene adipate-co-terephthalate) (PBAT).

Improved Delivery Performance of n-Butylidenephthalide-Polyethylene Glycol-Gold Nanoparticles Efficient for Enhanced Anti-Cancer Activity in Brain Tumor

n-butylidenephthalide (BP) has been verified as having the superior characteristic of cancer cell toxicity. Furthermore, gold (Au) nanoparticles are biocompatible materials, as well as effective carriers for delivering bio-active molecules for cancer therapeutics. In the present research, Au nanoparticles were first conjugated with polyethylene glycol (PEG), and then cross-linked with BP to obtain PEG-Au-BP nanodrugs. The physicochemical properties were characterized through ultraviolet-visible spectroscopy (UV-Vis), Fourier-transform infrared spectroscopy (FTIR), and dynamic light scattering (DLS) to confirm the combination of PEG, Au, and BP. In addition, both the size and structure of Au nanoparticles were observed through scanning electron microscopy (SEM) and transmission electron microscopy (TEM), where the size of Au corresponded to the results of DLS assay. Through in vitro assessments, non-transformed BAEC and DBTRG human glioma cells were treated with PEG-Au-BP drugs to investigate the tumor-cell selective cytotoxicity, cell uptake efficiency, and mechanism of endocytic routes. According to the results of MTT assay, PEG-Au-BP was able to significantly inhibit DBTRG brain cancer cell proliferation. Additionally, cell uptake efficiency and potential cellular transportation in both BAEC and DBTRG cell lines were observed to be significantly higher at 2 and 24 h. Moreover, the mechanisms of endocytosis, clathrin-mediated endocytosis, and cell autophagy were explored and determined to be favorable routes for BAEC and DBTRG cells to absorb PEG-Au-BP nanodrugs. Next, the cell progression and apoptosis of DBTRG cells after PEG-Au-BP treatment was investigated by flow cytometry. The results show that PEG-Au-BP could remarkably regulate the DBTRG cell cycle at the Sub-G1 phase, as well as induce more apoptotic cells. The expression of apoptotic-related proteins in DBTRG cells was determined through Western blotting assay. After treatment with PEG-Au-BP, the apoptotic cascade proteins p21, Bax, and Act-caspase-3 were all significantly expressed in DBTRG brain cancer cells. Through in vivo assessments, the tissue morphology and particle distribution in a mouse model were examined after a retro-orbital sinus injection containing PEG-Au-BP nanodrugs. The results demonstrate tissue integrity in the brain (forebrain, cerebellum, and midbrain), heart, liver, spleen, lung, and kidney, as they did not show significant destruction due to PEG-Au-BP treatment. Simultaneously, the extended retention period for PEG-Au-BP nanodrugs was discovered, particularly in brain tissue. The above findings identify PEG-Au-BP as a potential nanodrug for brain cancer therapies.

Time-Gated Imaging of Latent Fingerprints with Level 3 Details Achieved by Persistent Luminescent Fluoride Nanoparticles

The discovery of X-ray-charged persistent luminescence (PersL) in fluoride nanoparticles enables these materials to emit photons without real-time excitation, which provides a great possibility for the development of new luminescent nanotechnologies. In this work, we developed NaLuF₄:Mn nanoparticles with intense green PersL and functionalized surfaces and accordingly achieved time-gated imaging of latent fingerprints (LFPs) with Level 3 details. These surface-modified NaLuF₄:Mn nanoparticles exhibited near-spherical morphology, long-lasting emission for several hours, appropriate trap depth distribution, and tight chemical bonding with amino acids from fingerprints, thus greatly improving the accuracy of LFP imaging in a variety of environments. The developed NaLuF₄:Mn PersL nanoparticles are expected to find broad applications in the fields of LFP imaging and in vivo biological imaging.

Cross-Linking Agents for Electrospinning-Based Bone Tissue Engineering

Electrospun nanofibers are promising bone tissue scaffolds that support bone healing due to the body’s structural similarity to the extracellular matrix (ECM). However, the insufficient mechanical properties often limit their potential in bone tissue regeneration. Cross-linking agents that chemically interconnect as-spun electrospun nanofibers are a simple but effective strategy for improving electrospun nanofibers’ mechanical, biological, and degradation properties. To improve the mechanical characteristic of the nanofibrous bone scaffolds, two of the most common types of cross-linking agents are used to chemically crosslink electrospun nanofibers: synthetic and natural. Glutaraldehyde (GTA) is a typical synthetic agent for electrospun nanofibers, while genipin (GP) is a natural cross-linking agent isolated from gardenia fruit extracts. GP has gradually gained attention since GP has superior biocompatibility to synthetic ones. In recent studies, much more progress has been made in utilizing crosslinking strategies, including citric acid (CA), a natural cross-linking agent. This review summarizes both cross-linking agents commonly used to improve electrospun-based scaffolds in bone tissue engineering, explains recent progress, and attempts to expand the potential of this straightforward method for electrospinning-based bone tissue engineering.

Glucose-sensitive delivery of tannic acid by a photo-crosslinked chitosan hydrogel film for antibacterial and anti-inflammatory therapy

A glucose-sensitive antibacterial and anti-inflammatory hydrogel film with controlled release of tannic acid (TA) was synthesized using chitosan (CS). Specifically, the photo-crosslinked CS hydrogel was first obtained and then immersed in TA solution to generate composite hydrogel film with enhanced mechanical properties. Subsequently, N-hydroxysuccinimide/1-ethyl-3-(3-dimethylaminopropyl) carbodiimide based coupling chemistry was used to covalently crosslink glucose oxidase (GOx) to CS to obtain glucose sensitivity. The physicochemical properties, including chemical composition, enzyme-related characteristics, glucose responsiveness, and mechanical strength, were thoroughly investigated, followed by the cytotoxicity, antibacterial and anti-inflammatory tests. The results showed that the GOx immobilized on the film surface by covalent bonding gave better stability than those that were physically adsorbed. In addition, it could quickly and correspondingly modify its inner pore structure in response to the glucose stimulus and then control the loaded TA release. Meanwhile, the TA addition could enhance the film's mechanical properties. The composite hydrogel film demonstrated adequate biocompatibility and can inhibit NO, IL-6, and TNF-α production in stimulated macrophages, as well as Porphyromonas gingivalis growth, demonstrating effective antibacterial and anti-inflammatory activity.

Crucial role and mechanism of transcription-coupled DNA repair in bacteria

Transcription-coupled DNA repair (TCR) is presumed to be a minor sub-pathway of nucleotide excision repair (NER) in bacteria. Global genomic repair is thought to perform the bulk of repair independently of transcription. TCR is also believed to be mediated exclusively by Mfd-a DNA translocase of a marginal NER phenotype^1-3. Here we combined in cellulo cross-linking mass spectrometry with structural, biochemical and genetic approaches to map the interactions within the TCR complex (TCRC) and to determine the actual sequence of events that leads to NER in vivo. We show that RNA polymerase (RNAP) serves as the primary sensor of DNA damage and acts as a platform for the recruitment of NER enzymes. UvrA and UvrD associate with RNAP continuously, forming a surveillance pre-TCRC. In response to DNA damage, pre-TCRC recruits a second UvrD monomer to form a helicase-competent UvrD dimer that promotes backtracking of the TCRC. The weakening of UvrD-RNAP interactions renders cells sensitive to genotoxic stress. TCRC then recruits a second UvrA molecule and UvrB to initiate the repair process. Contrary to the conventional view, we show that TCR accounts for the vast majority of chromosomal repair events; that is, TCR thoroughly dominates over global genomic repair. We also show that TCR is largely independent of Mfd. We propose that Mfd has an indirect role in this process: it participates in removing obstructive RNAPs in front of TCRCs and also in recovering TCRCs from backtracking after repair has been completed.

Protein Nanoparticles: Uniting the Power of Proteins with Engineering Design Approaches

Protein nanoparticles, PNPs, have played a long-standing role in food and industrial applications. More recently, their potential in nanomedicine has been more widely pursued. This review summarizes recent trends related to the preparation, application, and chemical construction of nanoparticles that use proteins as major building blocks. A particular focus has been given to emerging trends related to applications in nanomedicine, an area of research where PNPs are poised for major breakthroughs as drug delivery carriers, particle-based therapeutics or for non-viral gene therapy.

Photosensitive EGFR-Targeted Nanocarriers for Combined Photodynamic and Local Chemotherapy

The major limitation of any cancer therapy lies in the difficulty of precisely controlling the localization of the drug in the tumor cells. To improve this drawback, our study explores the use of actively-targeted chemo-photo-nanocarriers that recognize and bind to epidermal growth factor receptor-overexpressing cells and promote the local on-demand release of the chemotherapeutic agent doxorubicin triggered by light. Our results show that the attachment of high concentrations of doxorubicin to cetuximab-IRDye700DX-mesoporous silica nanoparticles yields efficient and selective photokilling of EGFR-expressing cells mainly through singlet oxygen-induced release of the doxorubicin from the nanocarrier and without any dark toxicity. Therefore, this novel triply functionalized nanosystem is an effective and safe nanodevice for light-triggered on-demand doxorubicin release.

A General Protein Unfolding-Chemical Coupling Strategy for Pure Protein Hydrogels with Mechanically Strong and Multifunctional Properties

Protein-based hydrogels have attracted great attention due to their excellent biocompatible properties, but often suffer from weak mechanical strength. Conventional strengthening strategies for protein-based hydrogels are to introduce nanoparticles or synthetic polymers for improving their mechanical strength, but often compromise their biocompatibility. Here, a new, general, protein unfolding-chemical coupling (PNC) strategy is developed to fabricate pure protein hydrogels without any additives to achieve both high mechanical strength and excellent cell biocompatibility. This PNC strategy combines thermal-induced protein unfolding/gelation to form a physically-crosslinked network and a -NH2/-COOH coupling reaction to generate a chemicallycrosslinked network. Using bovine serum albumin (BSA) as a globular protein, PNC-BSA hydrogels show macroscopic transparency, high stability, high mechanical properties (compressive/tensile strength of 115/0.43 MPa), fast stiffness/toughness recovery of 85%/91% at room temperature, good fatigue resistance, and low cell cytotoxicity and red blood cell hemolysis. More importantly, the PNC strategy can be not only generally applied to silk fibroin, ovalbumin, and milk albumin protein to form different, high strength protein hydrogels, but also modified with PEDOT/PSS nanoparticles as strain sensors and fluorescent fillers as color sensors. This work demonstrates a new, universal, PNC method to prepare high strength, multi-functional, pure protein hydrogels beyond a few available today.

Overview and emerging trends in optical fiber aptasensing

Optical fiber biosensors have attracted growing interest over the last decade and quickly became a key enabling technology, especially for the detection of biomarkers at extremely low concentrations and in small volumes. Among the many and recent fiber-optic sensing amenities, aptamers-based sensors have shown unequalled performances in terms of ease of production, specificity, and sensitivity. The immobilization of small and highly stable bioreceptors such as DNA has bolstered their use for the most varied applications e.g., medical diagnosis, food safety and environmental monitoring. This review highlights the recent advances in aptamer-based optical fiber biosensors. An in-depth analysis of the literature summarizes different fiber-optic structures and biochemical strategies for molecular detection and immobilization of receptors over diverse surfaces. In this review, we analyze the features offered by those sensors and discuss about the next challenges to be addressed. This overview investigates both biochemical and optical parameters, drawing the guiding lines for forthcoming innovations and prospects in this ever-growing field of research.

Characterization of GPVI- or GPVI-CD39-Coated Nanoparticles and Their Impact on In Vitro Thrombus Formation

Traditional antithrombotic agents commonly share a therapy-limiting side effect, as they increase the overall systemic bleeding risk. A novel approach for targeted antithrombotic therapy is nanoparticles. In other therapeutic fields, nanoparticles have enabled site-specific delivery with low levels of toxicity and side effects. Here, we paired nanotechnology with an established dimeric glycoprotein VI-Fc (GPVI-Fc) and a GPVI-CD39 fusion protein, thereby combining site-specific delivery and new antithrombotic drugs. Poly(lactic-co-glycolic acid) (PLGA) nanoparticles, NP-BSA, NP-GPVI and NP-GPVI-CD39 were characterized through electron microscopy, atomic force measurements and flow cytometry. Light transmission aggregometry enabled analysis of platelet aggregation. Thrombus formation was observed through flow chamber experiments. NP-GPVI and NP-GPVI-CD39 displayed a characteristic surface coating pattern. Fluorescence properties were identical amongst all samples. NP-GPVI and NP-GPVI-CD39 significantly impaired platelet aggregation. Thrombus formation was significantly impaired by NP-GPVI and was particularly impaired by NP-GPVI-CD39. The receptor-coated nanoparticles NP-GPVI and the bifunctional molecule NP-GPVI-CD39 demonstrated significant inhibition of in vitro thrombus formation. Consequently, the nanoparticle-mediated antithrombotic effect of GPVI-Fc, as well as GPVI-CD39, and an additive impact of CD39 was confirmed. In conclusion, NP-GPVI and NP-GPVI-CD39 may serve as a promising foundation for a novel therapeutic approach regarding targeted antithrombotic therapy.

A Pencil-Lead Immunosensor for the Rapid Electrochemical Measurement of Anti-Diphtheria Toxin Antibodies

Diphtheria is a vaccine-preventable disease, yet immunization can wane over time to non-protective levels. We have developed a low-cost, miniaturized electroanalytical biosensor to quantify anti-diphtheria toxin (DTx) immunoglobulin G (anti-DTx IgG) antibody to minimize the risk for localized outbreaks. Two epitopes specific to DTx and recognized by antibodies generated post-vaccination were selected to create a bi-epitope peptide, biEP, by synthesizing the epitopes in tandem. The biEP peptide was conjugated to the surface of a pencil-lead electrode (PLE) integrated into a portable electrode holder. Captured anti-DTx IgG was measured by square wave voltammetry from the generation of hydroquinone (HQ) from the resulting immunocomplex. The performance of the biEP reagent presented high selectivity and specificity for DTx. Under the optimized working conditions, a logarithmic calibration curve showed good linearity over the concentration range of 10-5-10-1 IU mL-1 and achieved a limit of detection of 5 × 10-6 IU mL-1. The final device proved suitable for interrogating the immunity level against DTx in actual serum samples. Results showed good agreement with those obtained from a commercial enzyme-linked immunosorbent assay. In addition, the flexibility for conjugating other capture molecules to PLEs suggests that this technology could be easily adapted to the diagnoses of other pathogens.

Interaction of the Escherichia coli HU Protein with Various Topological Forms of DNA

E. coli histone-like protein HU has been shown to interact with different topological forms of DNA. Using radiolabeled HU, we examine the effects of DNA supercoiling on HU-DNA interactions. We show that HU binds preferentially to negatively supercoiled DNA and that the affinity of HU for DNA increases with increases in the negative superhelical density of DNA. Binding of HU to DNA is most sensitively influenced by DNA supercoiling within a narrow but physiologically relevant range of superhelicity (σ = -0.06-0). Under stoichiometric binding conditions, the affinity of HU for negatively supercoiled DNA (σ = -0.06) is more than 10 times higher than that for relaxed DNA at physiologically relevant HU/DNA mass ratios (e.g., 1:10). This binding preference, however, becomes negligible at HU/DNA mass ratios higher than 1:2. At saturation, HU binds both negatively supercoiled and relaxed DNA with similar stoichiometries, i.e., 5-6 base pairs per HU dimer. In our chemical crosslinking studies, we demonstrate that HU molecules bound to negatively supercoiled DNA are more readily crosslinked than those bound to linear DNA. At in vivo HU/DNA ratios, HU appears to exist predominantly in a tetrameric form on negatively supercoiled DNA and in a dimeric form on linear DNA. Using a DNA ligase-mediated nick closure assay, we show that approximately 20 HU dimers are required to constrain one negative supercoil on relaxed DNA. Although fewer HU dimers may be needed to constrain one negative supercoil on negatively supercoiled DNA, our results and estimates of the cellular level of HU argue against a major role for HU in constraining supercoils in vivo. We discuss our data within the context of the dynamic distribution of the HU protein in cells, where temporal and local changes of DNA supercoiling are known to take place.

Paper-based analytical devices for virus detection: Recent strategies for current and future pandemics

The importance of user-friendly, inexpensive, sensitive, and selective detection of viruses has been highlighted again due to the recent Coronavirus disease 2019 (COVID-19) pandemic. Among the analytical tools, paper-based devices (PADs) have become a leading alternative for point-of-care (POC) testing. In this review, we discuss the recent development strategies and applications in nucleic acid-based, antibody/antigen-based and other affinity-based PADs using optical and electrochemical detection methods for sensing viruses. In addition, advantages and drawbacks of presented PADs are identified. Current state and insights towards future perspectives are presented regarding developing POC diagnosis platform for COVID-19. This review considers state-of-the-art technologies for further development and improvement in PADs performance for virus detection.

BSA Hydrogel Beads Functionalized with a Specific Aptamer Library for Capturing Pseudomonas aeruginosa in Serum and Blood

Systemic blood stream infections are a major threat to human health and are dramatically increasing worldwide. Pseudomonas aeruginosa is a WHO-alerted multi-resistant pathogen of extreme importance as a cause of sepsis. Septicemia patients have significantly increased survival chances if sepsis is diagnosed in the early stages. Affinity materials can not only represent attractive tools for specific diagnostics of pathogens in the blood but can prospectively also serve as the technical foundation of therapeutic filtration devices. Based on the recently developed aptamers directed against P. aeruginosa, we here present aptamer-functionalized beads for specific binding of this pathogen in blood samples. These aptamer capture beads (ACBs) are manufactured by crosslinking bovine serum albumin (BSA) in an emulsion and subsequent functionalization with the amino-modified aptamers on the bead surface using the thiol- and amino-reactive bispecific crosslinker PEG₄-SPDP. Specific and quantitative binding of P. aeruginosa as the dedicated target of the ACBs was demonstrated in serum and blood. These initial but promising results may open new routes for the development of ACBs as a platform technology for fast and reliable diagnosis of bloodstream infections and, in the long term, blood filtration techniques in the fight against sepsis.

Targeted Nanoscale 3D Thermal Imaging of Tumor Cell Surface with Functionalized Quantum Dots

Measuring the changes in tumor cell surface temperature can provide insights into cellular metabolism and pathological features, which is significant for targeted chemotherapy and hyperthermic therapy. However, conventional micro-nano scale methods are invasive and can only measure the temperature of cells across a single plane, which excludes specific organelles. In this study, fluorescence quantum dots (QDs) are functionalized with the membrane transport protein transferrin (Tf) as a thermo-sensor specific for tumor cell membrane. The covalent conjugation is optimized to maintain the relative fluorescence intensity of the Tf-QDs to >90%. In addition, the Tf-QDs undergo changes in the fluorescence spectra as a function of temperature, underscoring its thermo-sensor function. Double helix point spread function imaging optical path is designed to locate the probe at nanoscale, and 3D thermal imaging technology is proposed to measure the local temperature distribution and direction of heat flux on the tumor cell surface. This novel targeted nanoscale 3D thermometry method can be a highly promising tool for measuring the local and global temperature distribution across intracellular organelles.

Enantioselective Antiport in Asymmetric Nanochannels

Enantioselective sensing and separation are major challenges. Nanochannel technologies are energy-saving and efficient for membrane separation. Herein, inspired by biological antiporter proteins, artificial nanochannels with antiporter behavior were fabricated for chiral sensing and separation. Tyrosine enantiomers were incorporated into hourglass-shaped nanochannels via stepwise modifications to fabricating multiligand-modified asymmetric channels. Chiral distinction of naproxen enantiomers was amplified in the l-Tyr/d-Tyr channels, with an enantioselectivity coefficient of 524, which was over 100-fold that of one-ligand-modified nanochannels. Furthermore, transport experiments evidenced the spontaneous antiport of naproxen enantiomers in the l-Tyr/d-Tyr channels. The racemic naproxen sample was separated via the chiral antiport process, with an enantiomeric excess of 71.2%. Further analysis using electro-osmotic flow experiments and finite-element simulations confirmed that the asymmetric modified multiligand was key to achieving separation of the naproxen enantiomers. We expect these multiligand-modified asymmetric nanochannels to provide insight into mimicking biological antiporter systems and offer an approach to energy-efficient and robust enantiomer separation.

Application of Epigallocatechin-3-gallate (EGCG) Modified 1-Ethyl-3-(3-dimethylaminopropylcarbodiimide hydrochloride/N-hydroxy-succinimide (EDC/NHS) Cross-Linked Collagen Membrane to Promote Macrophage Adhesion

The chemically cross-linking 1-ethyl-3-(3-dimethylaminopropylcarbodiimide hydrochloride/N-hydroxy-succinimide (EDC/NHS) collagen membrane endows such natural polymers with promising mechanical properties. Nevertheless, it is inadequate to advance the modulation of foreign body response (FBR) after implantation or guidance of tissue regeneration. In previous research, macrophages have a strong regulatory effect on regeneration, and such enhanced membranes underwent the modification with Epigallocatechin-3-gallate (EGCG) could adjust the recruitment and phenotypes of macrophages. Accordingly, we develop EGCG-EDC/NHS membranes, prepared with physical immersion, while focusing on the surface morphology through SEM, the biological activity of collagen was determined by FTIR, the activity and adhesion of cell culture in vitro, angiogenesis and monocyte/macrophage recruitment after subcutaneous implantation in vivo, are characterized. It could be concluded that it is hopeful EGCG-EDC/NHS collagen membrane can be used in implant dentistry for it not only retains the advantages of the collagen membrane itself, but also improves cell viability, adhesion, vascularization, and immunoregulation tendency.

Three-Dimensional Fluorescent Imaging to Identify Multi-Paths in Polymer Aging

It is of great significance to disclose the diverse aging pathways for polymers under multiple factors, so as to predict and control the potential aging evolution. However, the current methods fail to distinguish multiple pathways (multi-paths) of polymer aging due to the lack of spatiotemporal resolution. In this work, using polyimide as a model polymer, the hydroxyl, carboxyl, and amino groups from the polyimide aging process were labeled using specific fluorescent probes through boron-oxygen, imine, and thiourea linkages, respectively. When the excitation and emission wavelengths of each fluorescent probe were controlled, the multi-paths in polyimide aging can be visualized individually and simultaneously in three-dimensional fluorescent images. The overall aging process under hydrothermal treatment was destructured into the pyrolysis and hydrolysis pathways. Three-dimensional dynamic studies discovered that the increased humidity, along with the decreased oxygen content, could hamper the pyrolysis reaction and accelerate the hydrolysis reaction, leading to severe degradation of the overall polyimide aging. More importantly, the oxygen showed a higher regulation coefficient in accelerating the pyrolysis reaction, than the water vapor in motivating the hydrolysis reactions. Such a multidimensional identification methodology is able to guide the long-term use of polymers and control their aging process to a harmless direction in advance by tuning the contents of oxygen and water vapor.

A Silica Coating Approach to Enhance Bioconjugation on Metal-Encoded Polystyrene Microbeads for Bead-Based Assays in Mass Cytometry

Bead-based assays in flow cytometry are multiplexed analytical techniques that allow rapid and simultaneous detection and quantification of a large number of analytes from small volumes of samples. The development of corresponding bead-based assays in mass cytometry (MC) is highly desirable since it could increase the number of analytes detected in a single assay. The microbeads for these assays have to be labeled with metal isotopes for MC detection. One must also be able to functionalize the bead surface with affinity reagents to capture the analytes. Metal-encoded polystyrene microbeads prepared by multi-stage dispersion polymerization can produce effective isotopic signals in MC with relatively small bead-to-bead variations. However, functionalizing this microbead surface with bioaffinity agents remains challenging, possibly due to the interference of the steric-stabilizing PVP corona on the microbead surface. Here, we report a systematic investigation of a silica coating approach to coat Eu-encoded microbeads with thin silica shells, to functionalize the surface with amino groups, and to introduce bioaffinity agents. We examine the effect of silica shell roughness on the bioconjugation capacity and the effect of silica shell thickness on signal quality in MC measurements. To limit non-specific binding, we converted the amino groups on the microbead surface to carboxylic acid groups. Antibodies were effectively attached to microbead by first conjugating NeutrAvidin to the carboxyl-modified bead surface and then attaching biotinylated antibodies to the NeutrAvidin-modified bead surface. The antibody-modified microbeads can specifically capture antigens, which were marked with isotopic labels, and generate strong signals in MC. These are promising results for the development of bead-based assays in MC.

Anti-Fn14 Antibody-Conjugated Nanoparticles Display Membrane TWEAK-Like Agonism

Conventional bivalent IgG antibodies targeting a subgroup of receptors of the TNF superfamily (TNFSF) including fibroblast growth factor-inducible 14 (anti-Fn14) typically display no or only very limited agonistic activity on their own and can only trigger receptor signaling by crosslinking or when bound to Fcγ receptors (FcγR). Both result in proximity of multiple antibody-bound TNFRSF receptor (TNFR) molecules, which enables engagement of TNFR-associated signaling pathways. Here, we have linked anti-Fn14 antibodies to gold nanoparticles to mimic the “activating” effect of plasma membrane-presented FcγR-anchored anti-Fn14 antibodies. We functionalized gold nanoparticles with poly-ethylene glycol (PEG) linkers and then coupled antibodies to the PEG surface of the nanoparticles. We found that Fn14 binding of the anti-Fn14 antibodies PDL192 and 5B6 is preserved upon attachment to the nanoparticles. More importantly, the gold nanoparticle-presented anti-Fn14 antibody molecules displayed strong agonistic activity. Our results suggest that conjugation of monoclonal anti-TNFR antibodies to gold nanoparticles can be exploited to uncover their latent agonism, e.g., for immunotherapeutic applications.