Journal of Materials Chemistry B

Multi-responsive shape memory and self-healing hydrogels with gold and silver nanoparticles
Kılıç H and Ceylan D
Nanocomposite smart gels (Nc-) with self-healing and shape memory properties were designed in different types and size nano particles with temperature or light stimuli. Nc- networks were prepared by bulk polymerization of stearyl methacrylate (SM) and vinyl pyrrolidone (VP) in the presence of gold and silver nanoparticles. The structure, which does not contain any chemical cross-linkers, is held together by hydrophobic interactions while consisting of dipole-dipole bonds of the VP units and long alkyl groups in the side chains of the SM. Thanks to their crystalline regions, shape memory gels can self-heal with the presence of long hydrophobic chains, and furthermore, the nanoparticles (NPs) incorporated into the structure facilitate the controlled tuning of hydrophilic and hydrophobic properties. Nc- gels have the ability to self-heal by repairing mechanical damage independently or in the presence of a stimulus, as well as transforming from a temporary form to a permanent form. experiments on human skin fibroblast cells revealed that cell viability was over 100% after 48 hours and almost complete recovery was observed in scratch experiments at the end of this period. Based on the results obtained, Nc- gels have been shown to have the potential to be used as a non-invasive wound dressing material alternative to traditional wound closure methods.
HO-activated mitochondria-targeting photosensitizer for fluorescence imaging-guided combination photodynamic and radiotherapy
Tian Q, Zhu Z, Feng Y, Zhao S, Lin H, Zhang W and Xu Z
Radiotherapy is a primary modality in cancer treatment but is accompanied by severe side effects to healthy tissues and radiation resistance to some extent. To overcome these limitations, we developed a HO-responsive photosensitizer, CyBT, which could be activated by the upregulated HO induced by radiotherapy, enabling near-infrared fluorescence imaging-guided combination photodynamic and radiotherapy. The synthesis of CyBT began with the covalent linkage of hemicyanine and a free radical TEMPO through the click reaction, which demonstrated superior photodynamic properties. Shielding of fluorescence and photodynamic activity was achieved by incorporating phenylboronic acid pinacol ester. In X-ray irradiated tumor cells, the upregulation of HO activated CyBT, thereby restoring its fluorescence and photodynamic activity. Additionally, the positive charge of CyBT facilitated its targeting to the mitochondria within tumor cells for more efficiently triggering cell apoptosis. CyBT was co-assembled with a polymer PEG--PDPA to form acid-responsive nanoparticles (NPs-CyBT). This formulation enhanced tumor targeting, improved water solubility of CyBT, and extended circulation time. Utilizing fluorescence imaging to guide photodynamic and radiotherapy, NPs-CyBT can accurately target solid tumors in mice, and lead to tumor elimination, suggesting that it is a potential strategy for the effective treatment of malignant tumors.
Surface-enhanced Raman scattering for HSP 70A mRNA detection in live cells using silica nanoparticles and DNA-modified gold nanoparticles
Cho JE and Lim DK
Real-time monitoring of mRNA in living cells is crucial for understanding dynamic biological processes. Traditional methods such as northern blotting, PCR, and sequencing require cell lysis and do not allow for continuous observation. Fluorescence-based techniques have advanced this field, but they are limited by photobleaching, which hinders long-term monitoring. In this study, we designed a dual-probe system combining fluorescence and surface-enhanced Raman scattering (SERS) signals to monitor mRNA in living cells. Our system uses silica nanoparticles (SiNPs) with DNA sequences which are hybridized with fluorescent DNA sequences and DNA-modified gold nanoparticles (AuNPs) to detect heat shock protein 70A mRNA, which can be induced by photothermal damage from laser exposure. Following nanoparticle uptake and induction of heat shock, we observed a time-dependent decrease in fluorescence intensity and increase in SERS intensity, indicating successful mRNA monitoring in living cells. These findings suggest that our dual-probe system with SiNPs and AuNPs is a promising nanotechnological platform for sensitive, long-term monitoring of gene expression in living cells, offering significant potential for future biological and medical research.
Immunomodulatory effects of calcium phosphate microspheres: influences of particle size on macrophage polarization and secretion patterns
Wan Q, Tian L, Wang M, Chen F, Li X, Xiao Y, Chen X and Zhang X
This study investigated the immunomodulatory effects of calcium phosphate (CaP) microspheres, focusing on how particle size influenced macrophage polarization and cytokine secretion patterns. SEM analysis revealed that HA microspheres predominantly exhibited a spherical shape with distinct sizes and sub-micro-sized pores. The average particle sizes for the S1, S2, and S3 groups were 17.36 μm, 27.59 μm, and 47.14 μm, respectively. experiments demonstrated that small-sized S1 microspheres were more readily phagocytosed by macrophages, leading to a pro-inflammatory M1 phenotype characterized by increased gene expression of iNos and inflammatory cytokines (IL-1β, IL-6, TNF-α), and a higher proportion of CCR7 M1 macrophages. In contrast, the larger S2 and S3 microspheres favored an anti-inflammatory M2 phenotype, with higher expression of Arg and anti-inflammatory cytokines (IL-10), and greater proportions of CD206 M2 macrophages. Additionally, HA microspheres were injected into mouse quadriceps muscles, revealing significant differences in immune cell infiltration and tissue response. The S1 microspheres induced a prolonged and more severe inflammatory response, while the S2 and S3 microspheres were embedded in cell-rich tissue with minimal inflammation or fibrosis. It indicated the potential of larger microspheres (S2 and S3) to create a more favorable immune microenvironment that supported faster and more effective tissue healing. These findings underscore the importance of optimizing microsphere size to achieve desired immunomodulatory effects, thereby enhancing their clinical efficacy.
Intrafibrillar calcium carbonate mineralization of electrospinning polyvinyl alcohol/collagen films with improved mechanical and bioactive properties
Liu Y, Gao X, Li Y, Gao A, Zheng Z, Wei J, Yang H, Ping H, Xie H, Wang H, Wang W and Fu Z
Collagen films play an essential role in guided bone-regeneration (GBR) techniques, which create space, promote cell adhesion, and induce osteogenic differentiation. It is therefore crucial to design appropriate GBR films to facilitate bone regeneration. However, current electrospun collagen scaffolds used as bioactive materials have limited clinical applications due to their poor mechanical properties. In this study, polyvinyl alcohol (PVA)/collagen (Col) films were electrospun by mixing PVA and type I collagen solution. For the first time, the intrafibrillar mineralization of aragonite nanocrystals within the PVA/Col fibrils was achieved, resulting in the formation of a hierarchical, bioactive film. The PVA/Col-CaCO film exhibited good mechanical properties, with hardness and Young's modulus values of 211.6 ± 0.1 MPa and 5.6 ± 1.7 GPa, respectively. Furthermore, bone marrow mesenchymal stem cells (BMSCs) inoculated onto the PVA/Col-CaCO film demonstrated robust adhesion and proliferation. The mineralized fibrils effectively stimulated the growth of BMSCs while suppressing cell apoptosis. Besides, the PVA/Col-CaCO film significantly induced the osteogenic differentiation of BMSCs, revealing its potential biomedical applications in hard tissue engineering.
Eco-friendly self-cleaning coatings: fundamentals, fabrication, applications, and sustainability
Chavan TK and Sethi SK
Eco-friendly self-cleaning coatings have garnered significant attention due to their potential to address environmental concerns while offering remarkable properties. This review explores the dynamic field of such coatings, focusing on their fundamental principles, fabrication techniques, applications, and sustainability. The main findings of this review shed light on the fundamentals of a wetting phenomenon that underpins superhydrophobicity and self-cleaning, revealing how bio-inspired approaches and sustainable materials have enabled the development of sustainable coatings. This review is structured around the fundamental principles of superhydrophobicity, discussing the basic mechanisms and following different approaches to eco-friendly coatings, focusing on bio-inspired methods and sustainable materials. Next, detailed fabrication techniques are discussed to create such coatings followed by various applications across industries, emphasizing the real-world impact of eco-friendly coatings. The next section discusses the various advantages followed by investigating the environmental implications and discussing how these coatings contribute to sustainability. The review concludes with commercial superhydrophobic self-cleaning products, which reflect the current state of research, outlining the challenges, and providing insights into future directions and innovations in this field. By providing an in-depth analysis of their fabrication techniques, applications, and potential future directions, it serves as a valuable resource for researchers and engineers seeking to design eco-friendly superhydrophobic coatings.
Beyond : proposing a one-letter code for nucleobase-mediated molecular recognition
Ward AJ and Partridge BE
Nucleobase binding is a fundamental molecular recognition event central to modern biological and bioinspired supramolecular research. Underpinning this recognition is a deceptively simple hydrogen-bonding code, primarily based on the canonical nucleobases in DNA and RNA. Inspired by these biotic structures, chemists and biologists have designed abiotic hydrogen-bonding motifs that can interact with, augment, and reshape native molecular recognition, for applications ranging from genetic code expansion and nucleic acid recognition to supramolecular materials utilizing mono- and bifacial nucleobases. However, as the number of nucleobase-inspired motifs expands, the absence of a standard vocabulary to describe hydrogen bond (HB) patterns has led to a haphazard mixture of shorthand descriptors that are confusing and inconsistent. Alternative notations that specify individual HB sites (such as for donor-acceptor-donor) are cumbersome for biological and supramolecular constructs that contain many such patterns. This situation creates a barrier to sharing and interpreting nucleobase-related research across sub-disciplines, hindering collaboration and innovation. In this perspective, we aim to initiate discourse on this issue by considering what would be needed to formulate a concise one-letter code for the HB patterns associated with synthetic nucleobases. We first summarize some of the issues caused by the current absence of a consistent naming scheme. Subsequently, we discuss some key considerations in designing a coherent naming system. Finally, we leverage chemical rationale and pedagogical mnemonic considerations to propose a succinct and intuitive one-letter code for supramolecular two- and three-HB motifs. We hope that this discussion will spark conversations within our interdisciplinary community, thereby facilitating collaboration and easing communication among researchers engaged in synthetic nucleobase design.
Biomaterials enhancing localized cancer therapy activated anti-tumor immunity: a review
Yao J, Cui Z, Zhang F, Li H and Tian L
Localized cancer therapies such as radiotherapy, phototherapy, and chemotherapy are precise cancer treatment strategies aimed at minimizing systemic side effects. However, cancer metastasis remains the primary cause of mortality among cancer patients in clinical settings, and localized cancer treatments have limited efficacy against metastatic cancer. Therefore, researchers are exploring strategies that combine localized therapy with immunotherapy to activate robust anti-tumor immune responses, thereby eradicating metastatic cancer. Biomaterials, as novel materials, exhibit great potential in biomedical applications and have achieved great progress in clinic translation. This review introduces biomaterials and their applications in research focused on enhancing localized cancer treatment activated anti-tumor immunity. Additionally, the current challenges and future directions of biomaterials are also discussed, providing insights and references for related research.
Mucus-on-a-chip: investigating the barrier properties of mucus with organic bioelectronics
McCoy R, Wang K, Treiber J, Fu Y, Malliaras GG, Salleo A and Owens RM
Gastrointestinal (GI) mucus is a biologically complex hydrogel that acts as a partially permeable barrier between the contents of the GI tract and the mucosal epithelial lining. Its structural integrity is essential for the lubrication of the tract thereby aiding smooth transit of contents, and the protection of the epithelium from pathogens that seek to colonise and invade. Understanding its physical response to drugs and the microbiome is essential for treating many gastrointestinal infectious diseases. Given this, a static model of a GI mucus-on-a-chip has been developed with integrated electronics to monitor the barrier properties of mucus hydrogels. Its application for investigating the effect of drugs and biofilm formation on the mucus structure is validated using rheological techniques, confocal microscopy and electrochemical impedance spectroscopy (EIS).
A stable dual functional superhydrophobic coating to inhibit colonization, migration, and encrustation formation for urinary catheter applications
Miao J, Chai H, Niu L, Ouyang M and Wang R
Catheter-associated urinary tract infections are some of the most common hospital-acquired infections. , a common pathogen associated with urinary tract infections, has swarming motility and has pili on its surface for adhesion and flagella for upward movement. Migration of along the catheter surface can lead to ascending urinary tract infection. However, there is currently a lack of effective strategies to inhibit or delay the colonization, migration, and encrustation formation of in urinary catheters. This study developed a method for constructing a stable superhydrophobic coating on the surface of urinary catheters using a layer-by-layer approach. The adhesion and deposition of polydopamine were enhanced by pre-coating a liquid bandage film on the polydimethylsiloxane surface, resulting in a multilayer micro-nano composite structure on the catheter surface. This structure was combined with copper ions and superhydrophobic modifiers, ultimately resulting in a highly stable superhydrophobic coating. The coating retains its superhydrophobic properties after prolonged incubation, friction tests, and tape peeling tests. Importantly, the coating demonstrates excellent efficacy in inhibiting colonization, migration, and encrustation formation. This study offers novel insights into developing biomedical superhydrophobic coatings with enhanced stability and efficacy in inhibiting urinary tract bacterial infections.
Regulation of macrophage uptake through the bio-nano interaction using surface functionalized mesoporous silica nanoparticles with large radial pores
Wen J, Lei C, Hua S, Cai L, Dai H, Liu S, Li Y, Ivanovski S and Xu C
Porous nanoparticles, such as mesoporous silica nanoparticles (MSNs), have garnered significant interest for biomedical applications. Recently, MSNs with large radial pores have attracted increased attention because their unique pore structure and large pore size are suitable for delivering large molecules such as proteins and genes. Upon entry into biological systems like the bloodstream, nanoparticles quickly form a 'protein corona,' leading to alterations in their interactions with immune cells. In this study, we investigated the formation of protein corona on MSNs with large radial pores and various surface modifications using mass spectrometry. We also examined the effects of protein corona on the interaction between MSNs and macrophages. We prepared MSNs with large, cone-shaped radial pores (>30 nm) and six different functional groups, resulting in nanoparticles with neutral, negative, and positive surface charges. Our findings indicate that surface functional groups significantly alter the composition of the protein corona, affecting the bio-nano interaction of these surface-modified MSNs with macrophages. Notably, nanoparticles with similar surface charges exhibited distinct corona characteristics and were internalized differently by macrophages. This underscores the crucial role of the protein corona in determining the fate, behavior, and biological responses of nanoparticles. Our research sheds light on the significance of understanding and controlling protein corona formation to optimize the design and functionality of nanoparticle-based biomedical applications.
Bimetallic doped carbon dot nanozymes for enhanced sonodynamic and nanocatalytic therapy
Huang Y, Jia L, Zhang S, Yan L and Li L
Conventional inorganic semiconductors are not suitable for acting as nanozymes or sonosensitizers for therapeutic nanomedicine owing to the lack of excellent biocompatibility. Biocompatible carbon dots (CDs) exhibit a variety of biological activities due to their adjustable size and surface chemical modification; however, the simultaneous sonodynamic activity and multiple enzyme-mimicking catalytic activity of a single CD have not been reported. Herein, we report the development of bimetallic doped CDs as a high-efficiency nanozyme and sonosensitizer for enhanced sonodynamic therapy (SDT) and nanocatalytic therapy (NCT). By selecting metal-organic complexes like EDTA-FeNa as the carbon source, we ensure that the coordination environments of metal atoms are preserved throughout the low-temperature calcination process. Compared with the single metal doped CDs including Fe-CDs or Ni-CDs, the obtained Fe and Ni co-doped CDs (Fe-Ni-CDs) not only exhibit enhanced sonodynamic activity owing to the decreased bandgap, but also possess augmented dual enzyme-mimicking catalytic activities due to the synergistic effect of bimetallic ions. The Fe-Ni-CD-mediated cascade amplification of ROS generation could lead to the production of O and O˙ through SDT, the generation of ˙OH through POD-mimicking catalytic activity, and the provision of more O for SDT through CAT-mimicking catalytic activity. Through the integrated multifunctionality of Fe-Ni-CDs, we successfully enhanced the effectiveness of antitumor treatment with a single drug injection and a single US irradiation for enhanced SDT and NCT. This work provides a distinct paradigm of endowing CDs with sonodynamic and multiple enzyme-mimicking catalytic activities for enhanced SDT and NCT through bimetallic ion doping.
Gold nanostars and nanourchins for enhanced photothermal therapy, bioimaging, and theranostics
Delgado-Corrales BJ, Chopra V and Chauhan G
Photothermal therapy (PTT), a recently emerging method for eradicating tumors, utilizes hyperthermia induced by photo-absorbing materials to generate heat within cancer cells. Gold nanoparticles (AuNPs) have gained reliability for and applications in PTT due to their strong light absorbance, stability, and biocompatibility. Yet, their potential is limited by their spherical shape, impacting their size capabilities, electromagnetic enhancement effects, and localized surface plasmon resonance (LSPR). Anisotropic shapes have been tested and implemented in this treatment to overcome the limitations of spherical AuNPs. Nanostars (AuNSs) and nanourchins (AuNUs) offer unique properties, such as increased local electron density, improved catalytic activity, and an enhanced electromagnetic field, which have proven to be effective in PTT. Additionally, these shapes can easily reach the NIR-I and NIR-II window while exhibiting improved biological properties, including low cytotoxicity and high cellular uptake. This work covers the critical characteristics of AuNS and AuNUs, highlighting rough surface photothermal conversion enhancement, significantly impacting recent PTT and its synergy with other treatments. Additionally, the bioimaging and theranostic applications of these nanomaterials are discussed, highlighting their multifaceted utility in advanced cancer therapies.
Machine learning-assisted pattern recognition and imaging of multiplexed cancer cells a porphyrin-embedded dendrimer array
Hu J, Ni W, Han M, Zhan Y, Li F, Huang H and Han J
Early cancer detection plays a vital role in improving the survival rate of cancer patients, underscoring the importance of developing cancer detection methods. However, it is a great challenge to achieve simple, rapid, and accurate methods for simultaneously discerning various cancers. Herein we developed a 5-element porphyrin-embedded dendrimer-based sensor array, targeting the parallel discrimination of multiple cancers. The porphyrin-embedded dendrimers were modified with various functional groups to generate differentiated interactions with diverse cancer cells, which has been validated by fluorescence responses and laser confocal microscopy imaging. The dual-channel, five-element array, featuring ten signal outputs, achieved 100% accuracy in distinguishing between one human normal cell and six human cancerous cells, as well as in differentiating among mixed cells. Moreover, the screen 6-channel array can accurately distinguish 9 cells from mice and humans in minutes through optimization by multiple machine learning algorithms, including two normal cells and 7 cancerous cells with only 1000 cells, highlighting the significant potential of a porphyrin-embedded dendrimer-based parallel discriminating platform in early cancer diagnosis.
Polycyclic aromatic polymer nanoparticles show potent infectious particle adsorption capability
Oishi Y, Toyoda M, Hano N, Motozono C, Ueno T and Takafuji M
Nonspecific viral adsorption by polymer nanoparticles is more economical and superior in terms of operating cost and energy efficiency than viral adsorption using virus-specific antibodies and filtration techniques involving size exclusion in the order of tens of nanometres. In this study, we synthesised four types of polycyclic aromatic polymer (ArP) nanoparticles with different structures and evaluated their virus adsorption capability for infectious particles of the newly emerged severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). ArP nanoparticles with a diameter of approximately 500 nm were prepared by one-pot precipitation polymerisation using structural isomers of bifunctional dihydroxynaphthalene (1,5-dihydroxynaphthalene and 2,6-dihydroxynaphthalene) as phenol monomers, as well as 3-hydroxybenzoic acid and 3-aminophenol as comonomers to introduce carboxylic acid and amino groups, respectively. This wide range of phenolic monomers offers a powerful molecular design capability, enabling the optimisation of surface properties for the adsorption of various infectious virus particles. The virus adsorption capacity of the ArP nanoparticles exceeded 20 000 plaque-forming units and was found to be correlated with the nitrogen (primary and secondary amines) and quinone contents on the ArP nanoparticle surface. Furthermore, a polyvinylidene difluoride membrane filter uniformly coated with the ArP nanoparticles could remove viruses by filtration in a flow system.
Quantum DFT analysis and molecular docking investigation of various potential breast cancer drugs
Ayub MA, Tyagi AR, Srivastava SK and Singh P
Breast cancer is among the deadliest cancers worldwide, highlighting the urgent need for effective treatments. This study employs density functional theory (DFT) and molecular docking analyses to evaluate the anti-cancer efficacy and specificity of drug molecules lapatinib, tucatinib, neratinib, anastrozole, and letrozole. DFT analysis provides comprehensive insights into the structural, electronic, optical, and vibrational properties of these drugs, helping to elucidate their molecular stability and reactivity through global reactivity descriptors. Additionally, molecular docking simulations reveal the binding conformations and interaction profiles of these drugs with key breast cancer targets, underscoring their therapeutic potential. Docking results indicate that lapatinib, tucatinib, and neratinib have high binding affinities for HER2, with lapatinib exhibiting the strongest overall binding, particularly with PDK1 (PDB ID: 1UU7), PAK4 (PDB ID: 2X4Z), GSK3 (PDB ID: 1GNG), and HER2 (PDB ID: 2IOK). The stable hydrogen bonding and other interactions observed with lapatinib support its effectiveness in treating HER2-positive breast cancers, tucatinib's selective HER2 binding reduces off-target effects, while neratinib's irreversible binding provides prolonged inhibition, making it useful for overcoming resistance in HER2-positive cases. In contrast, anastrozole and letrozole show lower binding affinities for HER2 and EGFR due to their simpler structures but are potent aromatase inhibitors, making them effective in treating estrogen receptor-positive (ER-positive) breast cancers. In conclusion, DFT and molecular docking studies affirm the suitability of lapatinib, tucatinib, and neratinib for HER2-positive cancers, while anastrozole and letrozole are effective in ER-positive cancers, emphasizing the role of molecular structure and binding affinity in optimizing cancer treatment strategies.
Research progress of nitroxide radical-based MRI contrast agents: from structure design to application
Luo T, Wang B, Chen R, Qi Q, Wu R, Xie S, Chen H, Han J, Wu D and Cao S
Magnetic resonance imaging (MRI) remains a cornerstone of diagnostic imaging, offering unparalleled insights into anatomical structures and pathological conditions. Gadolinium-based contrast agents have long been the standard in MRI enhancement, yet concerns over nephrogenic systemic fibrosis have spurred interest in metal-free alternatives. Nitroxide radical-based MRI contrast agents (NO-CAs) have emerged as promising candidates, leveraging their biocompatibility and imaging capabilities. This review summaries the latest advancements in NO-CAs, focusing on synthesis methodologies, influencing effects of structures of NO-CAs on relaxation efficiency and their applications across various clinical contexts. Comprehensive discussions encompass small molecular, polymeric, and nano-sized NO-CAs, detailing their unique properties and potential clinical utilities. Despite challenges, NO-CAs represent a dynamic area of research poised to revolutionize MRI diagnostics. This review serves as a critical resource for researchers and practitioners seeking to navigate the evolving landscape of MRI contrast agents.
Development of a xanthene-based NIR fluorescent probe for accurate and sensitive detection of γ-glutamyl transpeptidase in cancer diagnosis and treatment
Lai CK, Magesh K, Velmathi S and Wu SP
γ-Glutamyl transpeptidase (GGT) regulates glutathione (GSH), essential for cell functions and linked to cancer. High GGT levels in tumors make it a valuable cancer biomarker. Current GGT detection methods often lack sensitivity and specificity. To address this, we developed XM-Glu, a new near-infrared (NIR) fluorescent probe. XM-Glu features a xanthene-based structure with a hydroxy xanthene fluorophore and a malononitrile group for NIR emission and reduced background noise. It has a self-immolating linker masked with glutamate acid, which activates fluorescence when GGT is present. XM-Glu can detect GGT in the range of 1.0 to 20 mU with a low detection limit of 0.067 mU mL. It showed high specificity and minimal interference in cellular assays. In mice, XM-Glu effectively detected GGT in tumor, liver, and kidney tissues. Its NIR properties provide real-time insights into GGT activity, improving cancer diagnosis and monitoring. This new technology enhances cancer research and helps better understand GGT's role in cancer progression.
Unravelling molecular mechanobiology using DNA-based fluorogenic tension sensors
Pal K
Investigations of the biological system have revealed many principles that govern regular life processes. Recently, the analysis of tiny mechanical forces associated with many biological processes revealed their significance in understanding biological functions. Consequently, this piqued the interest of researchers, and a series of technologies have been developed to understand biomechanical cues at the molecular level. Notable techniques include single-molecule force spectroscopy, traction force microscopy, and molecular tension sensors. Well-defined double-stranded DNA structures could possess programmable mechanical characteristics, and hence, they have become one of the central molecules in molecular tension sensor technology. With the advancement of DNA technology, DNA or nucleic acid-based robust tension sensors offer the possibility of understanding mechanobiology in the bulk to single-molecule level range with desired spatiotemporal resolution. This review presents a comprehensive account of molecular tension sensors with a special emphasis on DNA-based fluorogenic tension sensors. Along with a detailed discussion on irreversible and reversible DNA-based tension sensors and their application in super-resolution microscopy, a discussion on biomolecules associated with cellular mechanotransduction and key findings in the field are included. This review ends with an elaborate discussion on the current challenges and future prospects of molecular tension sensors.
Experimental and computational techniques to investigate the protein resistance of zwitterionic polymers
Lu M and Cheng N
Most surfaces undergo non-specific protein adsorption upon direct contact with protein-containing environments, resulting in the formation of a protein corona, and the nature and composition of the corona affect the properties of the material. Zwitterionic polymers have oppositely charged groups in their repeating units, which facilitate the formation of a hydration layer on the surface through electrostatic interactions. The hydration layer possesses a strong water-binding ability and can prevent protein adsorption. Therefore, the hydration effect of zwitterionic polymers has become a research focus, and many researchers have investigated this mechanism using experimental and computational methods. This paper reviews the experimental techniques and simulation methods to study the hydration effect of zwitterionic polymers and the advantages and disadvantages of different techniques are discussed.
Bioactive hydrogels based on lysine dendrigrafts as crosslinkers: tailoring elastic properties to influence hMSC osteogenic differentiation
Valeo M, Marie S, Rémy M, Menguy T, Le Coz C, Molinari M, Feuillie C, Granier F and Durrieu MC
Dendrigrafts are multivalent macromolecules with less ordered topology and higher branching than dendrimers. Exhibiting a high density of terminal amines, poly-L-lysine dendrigrafts of the fifth generation (DGL G5) allow hydrogel formation with tailorable crosslinking density and surface modification. This work presents DGL G5 as multifunctional crosslinkers in biomimetic PEG hydrogels to favour the osteogenic differentiation of human mesenchymal stem cells (hMSCs). DGL G5 reaction with dicarboxylic-acid PEG chains yielded amide networks of variable stiffness, measured at the macro and surface nanoscale. Oscillatory rheometry and compression afforded consistent values of Young's modulus, increasing from 8 to more than 30 kPa and correlating with DGL G5 concentration. At the surface level, AFM measurements showed the same tendency but higher values, from approximately 15 to more than 100 kPa, respectively. To promote cell adhesion and differentiation, the hydrogels were functionalised with a GRGDSPC peptide and a biomimetic of the bone morphogenetic protein 2 (BMP-2), ensuring the same grafting concentrations (between 2.15 ± 0.54 and 2.28 ± 0.23 pmols mm) but different hydrogel stiffness. 6 h after seeding on functionalised hydrogels in serum-less media, hMSC showed nascent adhesions on the stiffer gels and greater spreading than on glass controls with serum. After two weeks in osteogenic media, hMSC seeded on the stiffer gels showed greater spreading, more polygonal morphologies and increased levels of osteopontin, an osteoblast marker, compared to controls, which peaked on 22 kPa-gels. Together, these results demonstrate that DGL G5-PEG hydrogel bioactivity can influence the adhesion, spreading and early commitment of hMSCs.