Biomaterial Systems Research Articles

High-purity butoxydibutylborane catalysts enable the low-exothermic polymerization of PMMA bone cement with enhanced biocompatibility and osseointegration.

Polymethyl methacrylate (PMMA) based biomaterials have been widely utilized in clinics. However, currently, PMMA catalyzed by benzoyl peroxide (BPO) exhibits disquieting disadvantages including an exothermic polymerization reaction and a lack of bioactivity. Here, we first designed three industrial-scale synthesis methods for high-purity butoxydibutylborane (BODBB), achieving purity levels greater than 95% (maximum: 97.6%) and ensuring excellent fire safety. By utilizing BODBB as a catalyst, the highest polymerization temperature of PMMA bone cement (PMMA-BODBB) reached only 36.05 °C, ensuring that no thermal damage occurred after implantation. Compared to PMMA catalyzed by BPO and partially oxidized tributylborane (TBBO, catalyst of Super Bond C&B), PMMA-BODBB exhibited superior cell adhesion, proliferation, and osteogenesis, attributed to the reduced release of free radicals and toxic monomer, and moderate bioactive boron release. After injection into a 5 mm defect in the rat cranial bone, PMMA-BODBB demonstrated the highest level of osteointegration. This work not only presents an industrial-scale synthesis of high-purity BODBB, but also offers an innovative PMMA biomaterial system with intrinsic biocompatibility and osseointegration, paving the way for the next generation of PMMA-based biomaterials with broader applications.

3D Printing of a Biomimetic Myotendinous Junction Assisted by Artificial Intelligence.

The myotendinous junction (MTJ) facilitates force transmission between muscle and tendon to produce joint movement. The complex microarchitecture and regional mechanical heterogeneity of the myotendinous junction pose major challenges in creating this interface in vitro. Engineering this junction in vitro is challenging due to substantial fabrication difficulties in creating scaffolds with intricate microarchitecture and stiffness heterogeneity to mimic the native muscle-tendon interface. To address the current challenges in creating the MTJ in vitro, digital light processing (DLP)-based 3D printing was used to fabricate poly(glycerol sebacate)acrylate (PGSA)-based muscle-tendon scaffolds with physiologically informed microstructure and mechanical properties. Local mechanical properties in various regions of the scaffold were tuned by adjusting the exposure time and light intensity used during the continuous DLP-based 3D printing process to match the mechanical properties present in distinct regions of native muscle-tendon tissue using printing parameters defined by an artificial intelligence-trained algorithm. To evaluate how the presence of zonal stiffness regions can affect the phenotype of a 3D-printed MTJ in vitro model, three 3D-printed PGSA-based scaffold conditions were investigated: (1) a scaffold with muscle-informed mechanical properties in its entirety without zonal stiffness regions, (2) a scaffold with one end possessing native muscle stiffness and the other end possessing native tendon stiffness, and (3) a scaffold with three distinct regions whose stiffness values correspond to those of muscle on one end of the scaffold, MTJ in the middle junction of the scaffold, and tendon on the other end of the scaffold. The scaffold containing regional mechanical heterogeneity most similar to the native MTJ (condition 3) was found to enhance the expression of MTJ-related markers compared to those without the presence of zonal stiffness regions. Overall, the DLP-based 3D printing platform and biomaterial system developed in this study could serve as a useful tool for mimicking the complexity of the native MTJ, which possesses inherent geometric and mechanical heterogeneity.

Bioactives and Biomaterial Construction for Modulating Osteoclast Activities.

Bone tissue constitutes 15-20% of human body weight and plays a crucial role in supporting the body, coordinating movement, regulating mineral homeostasis, and hematopoiesis. The maintenance of bone homeostasis relies on a delicate balance between osteoblasts and osteoclasts. Osteoclasts, as the exclusive "bone resorbers" in the human skeletal system, are of paramount significance yet often receive inadequate attention. When osteoclast activity becomes excessive, it frequently leads to various bone metabolic disorders, subsequently resulting in secondary bone injuries, such as fractures. This not only reduces life quality of patients, but also imposes a significant economic burden on society. In response to the pressing need for biomaterials in the treatment of osteoclast dysregulation, there is a surge of research and investigations aimed at osteoclast regulation. Promising progress is achieved in this domain. This review seeks to provide a comprehensive understanding of how to modulate osteoclast activities. It summarizes bioactive substances that influence osteoclasts and elucidates strategies for constructing related biomaterial systems. It offers practical insights and ideas for the development and application of biomaterials and tissue engineering, with the hope of guiding the clinical treatment of osteoclast-related bone diseases using biomaterials in the future.

Predicting the Composition and Mechanical Properties of Seaweed Bioplastics from the Scientific Literature: A Machine Learning Approach for Modeling Sparse Data

The design of biodegradable polymeric materials is of increasing scientific interest due to accelerating levels of plastics pollution. One area of increasing interest is the design of biodegradable polymer films based on seaweed as a raw material. The goal of the study is to explore whether machine learning techniques can be used to predict the properties of unknown compositions based on existing data from the literature. Clustering algorithms are used, which show how some ingredients components at certain concentration levels alter the mechanical properties of the films. Robust regression algorithms with three popular models, namely decision tree, random forest, and gradient boosting. Their predictive capabilities are compared, resulting in the random forest algorithm being the most stable with the greatest predictive capacity. These analyses offer a decision support system for biomaterials manufacturing and experimentation. The results and conclusions of the study indicate that bioplastics made from seaweed have promising potential as a sustainable alternative to traditional plastics, discovering interesting additives to improve the performance of biopolymers. In addition, the machine learning approaches used provide effective tools for analyzing and predicting the properties of these materials in structured but highly sparse data.

Preparation and Evaluation of Hydrogel Containing Prednisolone Nanoparticles

Currently, nanoparticles technology is well known and it used to augment the rate of drug dissolution and considerably increased bioavailability. Nanoparticles have been combined with hydrogel to form nanoparticle-hydrogel hybrid system as a substitute to conventional dosage forms.
 The goal of this study is to prepare an effective hydrogel form containing prednisolone nanoparticles as a hybrid biomaterial system for transdermal application. Six hydrogel formulations containing prednisolone nanoparticles were prepared and characterized for particle size, entrapment efficiency, physical appearance, pH, drug content, spreadability test, viscosity, in-vitro drug release and ex-vivo diffusion. The results showed that the all preparations in the nanometer size and the drug content of prednisolone in hydrogel was ranged from 96.24% to 99.15% and there was a significant enhancement (p<0.05) in drug release and permeation from the prepared nanoparticles -hydrogel formulas when compared with plain hydrogel of prednisolone. From this study, it can be concluded that nanoparticle-hydrogel system could be a possible drug delivery technology for transdermal application of prednisolone drug.

Mechanically enhanced biogenesis of gut spheroids with instability-driven morphomechanics

Region-specific gut spheroids are precursors for gastrointestinal and pulmonary organoids that hold great promise for fundamental studies and translations. However, efficient production of gut spheroids remains challenging due to a lack of control and mechanistic understanding of gut spheroid morphogenesis. Here, we report an efficient biomaterial system, termed micropatterned gut spheroid generator (μGSG), to generate gut spheroids from human pluripotent stem cells through mechanically enhanced tissue morphogenesis. We show that μGSG enhances the biogenesis of gut spheroids independent of micropattern shape and size; instead, mechanically enforced cell multilayering and crowding is demonstrated as a general, geometry-insensitive mechanism that is necessary and sufficient for promoting spheroid formation. Combining experimental findings and an active-phase-field morphomechanics theory, our study further reveals an instability-driven mechanism and a mechanosensitive phase diagram governing spheroid pearling and fission in μGSG. This work unveils mechanobiological paradigms based on tissue architecture and surface tension for controlling tissue morphogenesis and advancing organoid technology.

Garlic extract enhances bioceramic bone scaffolds through upregulating ALP & BGLAP expression in hMSC-monocyte co-culture

Bone homeostasis is predicated by osteoblast and osteoclast cell cycles where gene expressions are responsible for their differentiation from human mesenchymal stem cells (hMSC) and monocytes, respectively. The pro-osteogenic potential of an hMSC-monocyte co-culture can be measured through complementary DNA (mRNA synthesis) within the nucleus, known as quantitative polymerase chain reaction (qPCR). Through this technique, the effects of garlic extract (allicin) release from calcium phosphate bone scaffolds on gene expression of bone forming and bone remodeling cells was explored. Results show this complex biomaterial system enhances hMSC differentiation through the upregulation of bone-forming proteins. Osteoblastic gene markers alkaline phosphatase (ALP) and osteocalcin (BGLAP), are respectively upregulated by 3-fold and 1.6-fold by day 14. These mature osteoblasts then upregulate the receptor activator of nuclear factor-kB ligand (RANKL) which recruits osteoclast cells, as captured by a nearly 2-fold higher osteoclast expression of tartrate-resistance acid-phosphatase (ACP5). This also activates antagonist osteoprotegerin (OPG) expression in osteoblasts, decreasing osteoclast resorption potential and ACP5 expression by day 21. The pro-osteogenic environment with garlic extract release is further quantified by a 4× increase in phosphatase activity and visibly captured in immunofluorescent tagged confocal images. Also corroborated by enhanced collagen formation in a preliminary in vivo rat distal femur model, this work collectively reveals how garlic extract can enhance bioceramic scaffolds for bone tissue regenerative applications.

Abstract P1129: Directing Revascularization In Vivo With Local Controlled Release Of An Optimized Angiogenic Growth Factor Cocktail

Reduced vascular perfusion due to aging, ischemia, or injury impedes healing and tissue function in conditions like skin ulcers and myocardial infarction, motivating development of therapies to restore vasculature locally in target tissues. We hypothesize that specific combinations of signaling molecules stimulate angiogenesis and vascular remodeling in the local tissue environment to increase perfused vessel density. Using a vascular tissue engineering approach with a fractional factorial design of experiments (DOE), we evaluated in vivo angiogenesis of combinations of ten growth factors, cytokines and/or enzymes including VEGF, bFGF, Shh, PDGF, IGF-1, EGF, TGF-β1, Ang-1, MCP-1 and MMP-9 in a subcutaneous gel plug assay in the WT immune competent rat. Our initial assessment with Matrigel identified 5 factors that maximized CD31+ vessel lumen density and aSMA+ encoated vessels at 7 days, warranting further evaluation. We developed a fully defined biomaterial system with covalently bound heparin to alginate mixed with collagen type 1 as an injectable gel. This defined biomaterial prolonged protein release up to 14 days in vitro versus Matrigel and unmodified alginate (2-4 days). The defined biomaterial was used for a second round DOE to deliver high (2 μg) and low (0.5 μg) doses of VEGF, bFGF, Shh, PDGF, and/or IGF-1. The defined biomaterial alone enhanced average lumen diameter 15-fold and endothelial cell infiltration 12-fold versus Matrigel. Perfused lumen density increased 16-fold with high Shh; aSMA-positive lumen wall area increased 4-fold with high VEGF, PDGF, and IGF-1; perfused vessel size increased 3-fold with high VEGF, bFGF, and Shh; and endothelial cell recruitment increased 2-fold with high IGF-1 relative to unloaded controls after 7 days in vivo. Empirical testing of 2- to 5-factor combinations showed that cocktail potency required initiation of angiogenic sprouting by VEGF or bFGF and vascularization responses were strongest in the presence of Shh and IGF-1. In conclusion, we identified sets of highly potent cocktails and leveraged controlled release from a defined biomaterial as a tailored revascularization therapy for local angiogenesis, vascular remodeling, and tissue regeneration.

Mechanobiology-informed biomaterial and tissue engineering strategies for influencing skeletal stem and progenitor cell fate.

Skeletal stem and progenitor cells (SSPCs) are the multi-potent, self-renewing cell lineages that form the hematopoietic environment and adventitial structures of the skeletal tissues. Skeletal tissues are responsible for a diverse range of physiological functions because of the extensive differentiation potential of SSPCs. The differentiation fates of SSPCs are shaped by the physical properties of their surrounding microenvironment and the mechanical loading forces exerted on them within the skeletal system. In this context, the present review first highlights important biomolecules involved with the mechanobiology of how SSPCs sense and transduce these physical signals. The review then shifts focus towards how the static and dynamic physical properties of microenvironments direct the biological fates of SSPCs, specifically within biomaterial and tissue engineering systems. Biomaterial constructs possess designable, quantifiable physical properties that enable the growth of cells in controlled physical environments both in-vitro and in-vivo. The utilization of biomaterials in tissue engineering systems provides a valuable platform for controllably directing the fates of SSPCs with physical signals as a tool for mechanobiology investigations and as a template for guiding skeletal tissue regeneration. It is paramount to study this mechanobiology and account for these mechanics-mediated behaviors to develop next-generation tissue engineering therapies that synergistically combine physical and chemical signals to direct cell fate. Ultimately, taking advantage of the evolved mechanobiology of SSPCs with customizable biomaterial constructs presents a powerful method to predictably guide bone and skeletal organ regeneration.

Mxene-Based Supramolecular Composite Hydrogels for Antioxidant and Photothermal Antibacterial Activities.

Bacterial infections and oxidative damage caused by various reactive oxygen species (ROS) pose a significant threat to human health. It is highly desirable to find an ideal biomaterial system with broad spectrum antibacterial and antioxidant capabilities. We present a new supramolecular antibacterial and antioxidant composite hydrogel made of chiral L-phenylalanine-derivative (LPFEG) as matrix and Mxene (Ti3 C2 Tx ) as filler material. The non-covalent interactions (H-bonding and π-π interactions) in between LPFEG and Mxene and the inversion of LPFEG chirality were verified by FTIR and CD spectroscopy. The composite hydrogels have shown improved mechanical properties revealed by rheological analysis. The composite hydrogel system exhibited photothermal conversion efficiency (40.79%), which enabled effective photothermal broad-spectrum antibacterial activities against both Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli, Pseudomonas aeruginosa) bacteria. Furthermore, the Mxene also enable the composite hydrogel to exhibit excellent antioxidant activity by efficiently scavenging free radicals like DPPH·, ABTS·+, and ·OH. These results indicate that the Mxene-based chiral supramolecular composite hydrogel, with improved rheological, antibacterial, and antioxidant properties has a great potential for biomedical applications. This article is protected by copyright. All rights reserved.

Smart dental materials for antimicrobial applications.

Smart biomaterials can sense and react to physiological or external environmental stimuli (e.g., mechanical, chemical, electrical, or magnetic signals). The last decades have seen exponential growth in the use and development of smart dental biomaterials for antimicrobial applications in dentistry. These biomaterial systems offer improved efficacy and controllable bio-functionalities to prevent infections and extend the longevity of dental devices. This review article presents the current state-of-the-art of design, evaluation, advantages, and limitations of bioactive and stimuli-responsive and autonomous dental materials for antimicrobial applications. First, the importance and classification of smart biomaterials are discussed. Second, the categories of bioresponsive antibacterial dental materials are systematically itemized based on different stimuli, including pH, enzymes, light, magnetic field, and vibrations. For each category, their antimicrobial mechanism, applications, and examples are discussed. Finally, we examined the limitations and obstacles required to develop clinically relevant applications of these appealing technologies.

Nanocarbon-Enforced Anisotropic MusCAMLR for Rapid Rescue of Mechanically Damaged Skeletal Muscles.

Mechanical damages to skeletal muscles could be detrimental to the active work hours and lifestyle of athletes, mountaineers, and security personnel. In this regard, the slowness of conventional treatment strategies and drug-associated side effects greatly demand the design and development of novel biomaterials, which can rescue such mechanically damaged skeletal muscles. To accomplish this demand, we have developed a musculoresponsive polymer-carbon composite for assisting myotubular regeneration (MusCAMLR). The MusCAMLR is enforced to attain anisotropic muscle-like characteristics while incorporating a smartly passivated nanoscale carbon material in the PNIPAM gel under physiological conditions as a stimulus, which is not achieved by the pristine nanocarbon system. The MusCAMLR establishes a specific mechanical interaction with muscle cells, supports myotube regeneration, maintains excellent mechanical similarity with the myotube, and restores the structural integrity and biochemical parameters of mechanically damaged muscles in a delayed onset muscle soreness (DOMS) rat model within a short period of 72 h. Concisely, this study discloses the potential of smartly passivated nanocarbon in generating an advanced biomaterial system, MusCAMLR, from a regularly used polymeric hydrogel system. This engineered polymer-carbon composite reveals its possible potential to be used as a nondrug therapeutic alternative for rescuing mechanically damaged muscles and probably can be extended for therapy of various other diseases including muscular dystrophy.

Enzyme-Mediated Nerve Growth Factor Release from Nanofibers Using Gelatin Microspheres.

Spinal cord injury is a complex environment, with many conflicting growth factors present at different times throughout the injury timeline. Delivery of multiple growth factors has received mixed results, highlighting a need to consider the timing of delivery for possibly antagonistic growth factors. Cell-mediated degradation of delivery vehicles for delayed release of growth factors offers an attractive way to exploit the highly active immune response in the spinal cord injury environment. In this study, growth factor-loaded gelatin microspheres (GMS) combined with methacrylated hyaluronic acid (MeHA) were electrospun to create GMS fibers (GMSF) for delayed release of growth factors (GFs). GMS were successfully combined with MeHA while electrospinning, with an average fiber diameter of 365 ± 10 nm and 44% ± 8% fiber alignment. GMSF with nerve growth factor (NGF) was tested on dissociated chick dorsal root ganglia cells. We further tested the effect of M1 macrophage-conditioned media (M1CM) to simulate macrophage invasion after spinal cord injury for cell-mediated degradation. We hypothesized that neurons grown on GMSF with loaded NGF would exhibit longer neurites in M1CM, showing a release of functional NGF, as compared with controls. GMSF in M1CM was significantly different from MeHA in serum-free media (SFM) and M0-conditioned media (M0CM), as well as GMSF in M0CM (p < 0.05). Moreover, GMSF + NGF in all media conditions were significantly different from MeHA in SFM and M0CM (p < 0.05). The goal of this study was to develop a biomaterial system where drug delivery is triggered by immune response, allowing for more control and longer exposure to encapsulated drugs. The spinal cord injury microenvironment is known to have a robust immune response, making this immune-medicated drug release system particularly significant for directed repair.

Modulation of myoblast differentiation by electroactive scaffold morphology and biochemical stimuli

The physico-chemical properties of the scaffold materials used for tissue regeneration strategies have a direct impact on cell shape, adhesion, proliferation, phenotypic and differentiation. Herewith, biophysical and biochemical cues have been widely used to design and develop biomaterial systems for specific tissue engineering strategies. In this context, the patterning of piezoelectric polymers that can provide electroactive stimuli represents a suitable strategy for skeletal muscle tissue engineering applications once it has been demonstrated that mechanoelectrical stimuli promote C2C12 myoblast differentiation. In this sense, this works reports on how C2C12 myoblast cells detect and react to physical and biochemical stimuli based on micropatterned poly(vinylidene fluoride-co-trifluoroethylene) (P(VDF-TrFE)) electroactive scaffolds produced by soft lithography in the form of arrays of lines and hexagons (anisotropic and isotropic morphology, respectively) combined with differentiation medium. The scaffolds were evaluated for the proliferation and differentiation of C2C12 myoblast cell line and it is demonstrated that anisotropic microstructures promote muscle differentiation which is further reinforced with the introduction of biochemical stimulus. However, when the physical stimulus is not adequate to the tissue, e.g. isotropic microstructure, the biochemical stimulus has the opposite effect, hindering the differentiation process. Therefore, the proper morphological design of the scaffold combined with biochemical stimulus allows to enhance skeletal muscle differentiation and allows the development of advanced strategies for effective muscle tissue engineering.

Aqueous Two-Phase Emulsion Bioresin for Facile One-Step 3D Microgel-Based Bioprinting.

Microgel assembly as void-forming bioinks in 3D bioprinting has evidenced recent success with a highlighted scaffolding performance of these bottom-up biomaterial systems in supporting the viability and function of the laden cells. Here, a ternary-component aqueous emulsion is established as a one-step strategy to integrate the methacrylated gelatin (GelMA) microgel fabrication and assembly through vat photopolymerization in situ using digital light processing (DLP)-based bioprinting. The as-proposed aqueous emulsion is featured with the partitioning of a secondary photo-crosslinkable polysaccharide, methacrylated galactoglucomannan (GGMMA) derived from plant source in both the dispersed phase of GelMA droplets and the continuous phase of dextran (Dex). As an emulgator, GGMMA renders enhanced stability of the aqueous emulsion bioresins. Strategically, the photo-crosslinkable GGMMA adheres the GelMA microgels that are conveniently converted from emulsion droplets to form hydrogel construct in layer-by-layer curing to accommodate the laden cells directly mixed in the aqueous emulsion. The spatially interconnected void space left by the removal of Dex benefits the cell growth under the guidance of the microgel surface and supports cell colonization within the macroscopic porous hydrogel. This work amends a low-concentration and cost-effective bioresin that is highly applicable for facilely fabricating microgel assembly as a porous hydrogel construct in DLP-based bioprinting.

Development and characterization of Factor Xa-responsive materials for applications in cell culture and biologics delivery.

Stimuli-responsive biomaterials may be used to better control the release of bioactive molecules or cells for applications involving drug delivery and controlled cell release. In this study, we developed a Factor Xa (FXa)-responsive biomaterial capable of controlled release of pharmaceutical agents and cells from in vitro culture. FXa-cleavable substrates were formed as hydrogels that degraded in response to FXa enzyme over several hours. Hydrogels were shown to release both heparin and a model protein in response to FXa. Additionally, RGD-functionalized FXa-degradable hydrogels were used to culture mesenchymal stromal cells (MSCs), enabling FXa-mediated cell dissociation from hydrogels in a manner that preserved multicellular structures. Harvesting MSCs using FXa-mediated dissociation did not influence their differentiation capacity or indoleamine 2,3-dioxygenase (IDO) activity (a measure of immunomodulatory capacity). In all, this FXa-degradable hydrogel is a novel responsive biomaterial system that may be used for on-demand drug delivery, as well as for improving processes for in vitro culture of therapeutic cells.

Cell-instructive biomaterials in tissue engineering and regenerative medicine.

The field of biomaterials aims to improve regenerative outcomes or scientific understanding for a wide range of tissue types and ailments. Biomaterials can be fabricated from natural or synthetic sources and display a plethora of mechanical, electrical, and geometrical properties dependent on their desired application. To date, most biomaterial systems designed for eventual translation to the clinic rely on soluble signaling moieties, such as growth factors, to elicit a specific cellular response. However, these soluble factors are often limited by high cost, convoluted synthesis, low stability, and difficulty in regulation, making the translation of these biomaterials systems to clinical or commercial applications a long and arduous process. In response to this, significant effort has been dedicated to researching cell-directive biomaterials which can signal for specific cell behavior in the absence of soluble factors. Cells of all tissue types have been shown to be innately in tune with their microenvironment, which is a biological phenomenon that can be exploited by researchers to design materials that direct cell behavior based on their intrinsic characteristics. This review will focus on recent developments in biomaterials that direct cell behavior using biomaterial properties such as charge, peptide presentation, and micro- or nano-geometry. These next generation biomaterials could offer significant strides in the development of clinically relevant medical devices which improve our understanding of the cellular microenvironment and enhance patient care in a variety of ailments.

Correlative microscopy approach for micro- and nanoplastics detection in plant matrix

The world-wide plastics pollution into nature enters the human food chain as degradation products, influencing environmental habitat and health. Micro- and nanoplastics as foreign bodies contaminating beverages and foods on the cellular level are likely to have a long-term impact on nutrition growth, public and personal health. Nanoparticles and their spatial location are generally difficult to detect in biological specimens, especially plastic particles due to their analogous hydrocarbon-based matrix. Reliable analysis methods for the discovery of micro- and nanoplastic particles in entities are not fully established yet. We are therefore developing a correlative workflow for detecting plastics residuals in cellular tissue. We determined that light microscopy (LM) is usable for a coarse estimation of the contamination grade of plant samples. Due to its optical diffraction limit, LM rather detects nanoparticle patches than single particles, shown with fluorescent particles. Scanning electron microscopy (SEM) instead provides higher resolution, especially for single particle detection. EM sample staining is still required to depict polymerous nanoparticle specimens. Using LM and SEM data in a CLEM approach with TESCAN CORAL, discovery of contaminated plant areas is possible with single nanoparticle resolution. It reveals that nanoparticles seem to be tightly attached to the plant material. It indicates further that basic food cleaning procedures might be insufficient for particle removal. The workflow circumvents correlative sample 3D-topography issues. But insights into the plant matrix is best possible with z-information. Therefore, we additionally use focused ion beam (FIB) to determine inclusions of micro- and nanoplastics in the tissue/cellular matrix, investigating the optimal procedural approach as model for biomaterial systems. Procedural correlative microscopy provides a promising analysis method for the semiquantitative analysis of micro- and nanoparticles plant contaminations.

Ambient Tip-Enhanced Two Photon Photoluminescence from CdSe/ZnS Quantum Dots

Nonlinear nano-optical measurements that combine ultrafast spectroscopy with tools of scanning probe microscopy are scarce. This is particularly the case when high spatial resolution on the order of a few nanometers is sought after in experiments performed under ambient laboratory conditions. In this work, we demonstrate the latter through measurements that track two-photon photoluminescence from aggregates of CdSe/ZnS quantum dots with sub-5 nm spatial resolution. Our proof-of-principle measurements that only take advantage of a plasmonic probe (as opposed to a gap mode) pave the way for nonlinear photoluminescence-based spectral nanoimaging of realistic/heterogeneous (bio) molecular and (bio) material systems.

Sodium Phytate‐Incorporated Gelatin‐Silicate Nanoplatelet Composites for Enhanced Cohesion and Hemostatic Function of Shear‐Thinning Biomaterials

Inside Back Cover: Gelatin-silicate nanoplatelets have leveraged shear-thinning biomaterial (STB) systems as an alternative to coiling and clipping for the treatment of vascular anomalies through minimally invasive procedures. Occlusion of aneurysms depends on the stability and hemostatic efficacy of STB. Introducing sodium phytate in Gelatin-silicate nanoplatelets-based STBs enables major improvements in cohesion and hemostatic effects for a more effective therapeutic effect in endovascular embolization repair. This is reported by Alireza Hassani Najafabadi, Han-Jun Kim, Ali Khademhosseini, and co-workers in article number 2200333.