Biomaterial Systems Research Articles

Realistic Risk Assessment of Soil Microplastics Is Hampered by a Lack of Eligible Data on Particle Characteristics: A Call for Higher Reporting Standards

ADVERTISEMENT RETURN TO ISSUEPREVViewpointNEXTRealistic Risk Assessment of Soil Microplastics Is Hampered by a Lack of Eligible Data on Particle Characteristics: A Call for Higher Reporting StandardsUwe Schnepf*Uwe SchnepfUniversity of Stuttgart, Institute of Biomaterials and Biomolecular Systems, Research Unit Biodiversity and Scientific Diving, Pfaffenwaldring 57, 70659 Stuttgart, Germany*[email protected]More by Uwe SchnepfView Biographyhttps://orcid.org/0000-0003-3955-4484Cite this: Environ. Sci. Technol. 2023, 57, 1, 3–4Publication Date (Web):December 12, 2022Publication History Received2 November 2022Published online12 December 2022Published inissue 10 January 2023https://doi.org/10.1021/acs.est.2c08151Copyright © 2022 The Author. Published by American Chemical SocietyRIGHTS & PERMISSIONSArticle Views708Altmetric-Citations-LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (1 MB) Get e-AlertsSUBJECTS:Particle size,Particles,Polymer particles,Risk assessment,Soils Get e-Alerts

Engineering Skeletal Muscle Grafts with PAX7::GFP-Sorted Human Pluripotent Stem Cell-Derived Myogenic Progenitors on Fibrin Microfiber Bundles for Tissue Regeneration.

Tissue engineering strategies that combine human pluripotent stem cell-derived myogenic progenitors (hPDMs) with advanced biomaterials provide promising tools for engineering 3D skeletal muscle grafts to model tissue development in vitro and promote muscle regeneration in vivo. We recently demonstrated (i) the potential for obtaining large numbers of hPDMs using a combination of two small molecules without the overexpression of transgenes and (ii) the application of electrospun fibrin microfiber bundles for functional skeletal muscle restoration following volumetric muscle loss. In this study, we aimed to demonstrate that the biophysical cues provided by the fibrin microfiber bundles induce hPDMs to form engineered human skeletal muscle grafts containing multinucleated myotubes that express desmin and myosin heavy chains and that these grafts could promote regeneration following skeletal muscle injuries. We tested a genetic PAX7 reporter line (PAX7::GFP) to sort for more homogenous populations of hPDMs. RNA sequencing and gene set enrichment analyses confirmed that PAX7::GFP-sorted hPDMs exhibited high expression of myogenic genes. We tested engineered human skeletal muscle grafts derived from PAX7::GFP-sorted hPDMs within in vivo skeletal muscle defects by assessing myogenesis, engraftment and immunogenicity using immunohistochemical staining. The PAX7::GFP-sorted groups had moderately high vascular infiltration and more implanted cell association with embryonic myosin heavy chain (eMHC) regions, suggesting they induced pro-regenerative microenvironments. These findings demonstrated the promise for the use of PAX7::GFP-sorted hPDMs on fibrin microfiber bundles and provided some insights for improving the cell-biomaterial system to stimulate more robust in vivo skeletal muscle regeneration.

Phenyl boronic acid -PEG-stearic acid biomaterial-based and sialic acid targeted nanomicelles for colon cancer treatment

This study aims to develop and evaluate a sialic acid receptor-targeting biomaterial for an effective delivery of usnic acid (UA). The novel biomaterial system is composed of three different parts; (1) stearic acid (SA) a hydrophobic core for encapsulation of UA, (2) PEG spacer to make conjugate amphiphilic, and (3) at the periphery phenylboronic acid (PBA) for cancer cell targeting. The synthesized PBA-PEG-SA biomaterial was characterized by FTIR NMR, and MALDI-TOF analysis. An average molecular weight of PBA-PEG-SA was about 3896 Da. The PBA-PEG-SA biomaterial was self-assembled into the nanomicelles with a 460 μg/mL CMC value. The UA-loaded PBA-PEG-SA nanomicelles (UPNM) were analysed by DLS, TEM, FTIR NMR, DSC and XRD techniques. The average particle size of UPNM was about 160 nm and its spherical nature was confirmed by TEM analysis. The synthesized biomaterial provided a pH-sensitive and controlled release of encapsulated UA with < 10% release at gastric pH 1.2 while > 90% release at intestinal pH 6.8. In vitro cytotoxicity potential of developed UPNM was investigated against HCT116 human colon cancer cells. The in vitro results proved that the synthesized PBA-PEG-SA biomaterial had good biocompatibility and PBA decorated nanomicelles could be successfully uptaken by HCT116 cancer cells. The observed IC50 value for UPNM (5.37 ± 0.78 μg/mL) was significantly lower (p < 0.01) than pure UA (8.57 ± 0.26 μg/mL) or non-targeted UA-loaded nanomicelles (8.36 ± 0.63 μg/mL). Further, the targeted nanomicelles showed higher apoptosis and greater control over the colony formation ability of HCT116 cells than pure drug or non-targeted UA-loaded nanomicelles.

Hybrid membrane of flat silk cocoon and carboxymethyl chitosan formed through hot pressing promotes wound healing and repair in a rat model.

Clinical wound management is always a relatively urgent problem. Moreover, wounds, especially severe wounds with excessive tension or excessive movement are prone to tissue infection, necrosis, and other negative effects during healing. Therefore, research has aimed to develop low-cost complementary treatments to address the urgent need for an innovative low-cost dressing that can adapt to high mechanical requirements and complex wound conditions. At present, tissue engineering to produce artificial skin with a structure similar to that of normal skin is one effective method to solve this challenge in the regeneration and repair of serious wounds. The present study hot pressed flat silk cocoons (FSC) with carboxymethyl chitosan (CMCS) to generate a cross-linked binding without enzymes or cross-linking agents that simulated the 3D structural composites of the skin cuticle. This hybrid membrane showed potential to reduce inflammatory cells and promote neovascularization in skin wound repair. After hot pressing at 130°C and 20 Mpa, the FSC/CMCS composite material was denser than FSC, showed strong light transmission, and could be arbitrarily cut. Simulating the normal skin tissue structure, the hybrid membrane overcame the poor mechanical properties of traditional support materials. Moreover, the combination of protein and polysaccharide simulated the extracellular matrix, thus providing better biocompatibility. The results of this study also demonstrated the excellent mechanical properties of the FSC/CMCS composite support material, which also provided a low-cost and environmentally friendly process for making dressings. In addition, the results of this study preliminarily reveal the mechanism by which the scaffolds promoted the healing of full-thickness skin defects on the back of SD rats. In vivo experiments using a full-thickness skin defect model showed that the FSC/CMCS membranes significantly promoted the rate of wound healing and also showed good effects on blood vessel formation and reduced inflammatory reactions. This bionic support structure, with excellent repair efficacy on deep skin defect wounds, showed potential to further improve the available biomaterial systems, such as skin and other soft tissues.

The advances of blood clots used as biomaterials in regenerative medicine.

The physiologic process of blood clot formation is well understood and occurs naturally in the setting of tissue injury to achieve hemostasis and begin the process of wound healing. While the investigation of blood clots as a biomaterial is still in the early stages, there has been some research with similar biomaterials made of the components of blood clots that support the innovative idea of using an autologous blood clot as a scaffold or delivery method for therapeutic agents. Here, we review the physiology of blood clots in wound healing and how using blood clots as a biomaterial and delivery system can potentially promote wound healing, provide targeted therapeutic agent delivery and use it as an innovative tool in regenerative medicine.

Cartilage-penetrating hyaluronic acid hydrogel preserves tissue content and reduces chondrocyte catabolism.

Articular cartilage injuries have a limited healing capacity and, due to inflammatory and catabolic activities, often experience progressive degeneration towards osteoarthritis. Current repair techniques generally provide short-term symptomatic relief; however, the regeneration of hyaline cartilage remains elusive, leaving both the repair tissue and surrounding healthy tissue susceptible to long-term wear. Therefore, methods to preserve cartilage following injury, especially from matrix loss and catabolism, are needed to delay, or even prevent, the deteriorative process. The goal of this study was to develop and evaluate a cartilage-penetrating hyaluronic-acid (HA) hydrogel to improve damaged cartilage biomechanics and prevent tissue degeneration. At time zero, the HA-based hydrogel provided a 46.5% increase in compressive modulus and a decrease in permeability after simulated degeneration of explants (collagenase application). Next, in a degenerative culture model (interleukin-1β [IL-1β] for 2weeks), hydrogel application prior to or midway through the culture mitigated detrimental changes to compressive modulus and permeability observed in non-treated explants. Furthermore, localized loss of proteoglycan was observed in degenerative culture conditions alone (non-treated), but hydrogel administration significantly improved the retention of matrix elements. Finally, NITEGE staining and gene expression analysis showed the ability of the HA gel to decrease chondrocyte catabolic activity. These results highlight the importance of reinforcing damaged cartilage with a biomaterial system to both preserve tissue content and reduce catabolism associated with injury and inflammation.

IL-10-Functionalized Hydrogels Support Immunosuppressive Dendritic Cell Phenotype and Function.

Biomaterial systems such as hydrogels enable localized delivery and postinjection modulation of cellular therapies in a wide array of contexts. Biomaterials as adjuvants have been an active area of investigation, but the study of functionalized biomaterials supporting immunosuppressive cell therapies for tolerogenic applications is still nascent. Here, we developed a 4-arm poly(ethylene-glycol)-maleimide (PEG-4MAL) hydrogel functionalized with interleukin-10 (IL-10) to improve the local delivery and efficacy of a cell therapy against autoimmune disease. The biophysical and biochemical properties of PEG-4MAL hydrogels were optimized to support dendritic cell (DC) viability and an immature phenotype. IL-10-functionalized PEG-4MAL (PEG-IL10) hydrogels exhibited controlled IL-10 release, extended the duration of DC support, and protected DCs from inflammatory assault. After incorporation in PEG-IL10 hydrogels, these DCs induced CD25+FoxP3+ regulatory T cells (Tregs) during in vitro coculture. These studies serve as a proof-of-concept for improving the efficacy of immunosuppressive cell therapies through biomaterial delivery. The flexible nature of this system enables its widespread application across a breadth of other tolerogenic applications for future investigation.

De Novo Self-Assembling Peptides Mediate the Conversion of Temozolomide and Delivery of a Model Drug into Glioblastoma Multiforme Cells

Glioblastoma multiforme (GBM) is the most aggressive central nervous system tumor, and standard treatment, including surgical resection, radiation, and chemotherapy, has not significantly improved patient outcomes over the last 20 years. Temozolomide (TMZ), the prodrug most commonly used to treat GBM, must pass the blood–brain barrier and requires a basic pH to convert to its active form. Due to these barriers, less than 30% of orally delivered TMZ reaches the central nervous system and becomes bioactive. In this work, we have developed a novel biomaterial delivery system to convert TMZ to its active form and that shows promise for intracellular TMZ delivery. Self-assembling peptides were characterized under several different assembly conditions and evaluated for TMZ loading and conversion. Both solvent and method of assembly were found to affect the supramolecular and secondary structure of peptide assemblies. Additionally, as peptides degraded in phosphate-buffered saline, TMZ was rapidly converted to its active form. This work demonstrates that peptide-based drug delivery systems can effectively create a local stimulus during drug delivery while remaining biocompatible. This principle could be used in many future biomedical applications in addition to cancer treatment, such as wound healing and regenerative medicine.

Human gelatin-based composite hydrogels for osteochondral tissue engineering and their adaptation into bioinks for extrusion, inkjet, and digital light processing bioprinting

The investigation of novel hydrogel systems allows for the study of relationships between biomaterials, cells, and other factors within osteochondral tissue engineering. Three-dimensional (3D) printing is a popular research method that can allow for further interrogation of these questions via the fabrication of 3D hydrogel environments that mimic tissue-specific, complex architectures. However, the adaptation of promising hydrogel biomaterial systems into 3D-printable bioinks remains a challenge. Here, we delineated an approach to that process. First, we characterized a novel methacryloylated gelatin composite hydrogel system and assessed how calcium phosphate and glycosaminoglycan additives upregulated bone- and cartilage-like matrix deposition and certain genetic markers of differentiation within human mesenchymal stem cells (hMSCs), such as RUNX2 and SOX9. Then, new assays were developed and utilized to study the effects of xanthan gum and nanofibrillated cellulose, which allowed for cohesive fiber deposition, reliable droplet formation, and non-fracturing digital light processing (DLP)-printed constructs within extrusion, inkjet, and DLP techniques, respectively. Finally, these bioinks were used to 3D print constructs containing viable encapsulated hMSCs over a 7 d period, where DLP printed constructs facilitated the highest observed increase in cell number over 7 d (∼2.4×). The results presented here describe the promotion of osteochondral phenotypes via these novel composite hydrogel formulations, establish their ability to bioprint viable, cell-encapsulating constructs using three different 3D printing methods on multiple bioprinters, and document how a library of modular bioink additives affected those physicochemical properties important to printability.

Advancing Engineered Heart Muscle Tissue Complexity with Hydrogel Composites.

A heart attack results in the permanent loss of heart muscle and can lead to heart disease, which kills more than 7 million people worldwide each year. To date, outside of heart transplantation, current clinical treatments cannot regenerate lost heart muscle or restore full function to the damaged heart. There is a critical need to create engineered heart tissues with structural complexity and functional capacity needed to replace damaged heart muscle. The inextricable link between structure and function suggests that hydrogel composites hold tremendous promise as a biomaterial-guided strategy to advance heart muscle tissue engineering. Such composites provide biophysical cues and functionality as a provisional extracellular matrix that hydrogels cannot on their own. This review describes the latest advances in the characterization of these biomaterial systems and using them for heart muscle tissue engineering. The review integrates results across the field to provide new insights on critical features within hydrogel composites and perspectives on the next steps to harnessing these promising biomaterials to faithfully reproduce the complex structure and function of native heart muscle.

Design of gripping devices based on a globoid transmission for a robotic biomaterial aliquoting system

AbstractEvery year the shortage of biosamples is increasing, while the requirements for their quality are constantly tightening, which requires the introduction of new technological solutions. To solve these problems, a robotic system for aliquoting biological liquid was developed. The aliquotation process is described. The station includes a serial robot on which a gripper based on a globoid worm is installed. The gripping device is parameterized and takes into account the gripping force for different finger deflections. 3D models were developed using Computer Aided Design (CAD) system tools, after which working layouts were created using 3D printing. The design process and test results are discussed to show the efficiency of the built prototype with lab tests.

Abstract P1141: Heparinized Alginate And Collagen-based Hydrogels Enhance Localized Vascularization In Ischemic Tissue

Over 800,000 myocardial infarctions (MI) occur annually in the United States alone, 25% of which represent a repeat occurrence further indicating chronic ischemia in the myocardium. Cardiovascular regeneration is largely dependent on the stimulation of blood vessel development for recovering tissue perfusion and modulating ventricular remodeling. The delivery of angiogenic growth factors and cytokines has demonstrated the ability to initiate angiogenesis and vascular network formation in cardiac tissue, with localization of bioactive molecules more effective than systemic delivery. Alginate, with its high biocompatibility and biodegradation, represents a promising hydrogel material for factor delivery due to its high protein loading capacity. We hypothesize that covalently binding heparin to alginate will increase binding and retention to subsequently lengthen the local release duration of vascular-promoting factors. For greater tuning and biointegration, collagen and alginate hydrogel designs were optimized for both injection and co-implantation of a solid film with hiPSC-CM based ECTs in a rat model of myocardial infarction. Injectable and solid formulations showed stiffnesses of 50 +/- 2 kPa and 900 +/- 193 kPa, respectively, which was maintained for up to 6 hours of dry time. Release profiles showed sustained growth factor release, with 65% of the total content released at 7 days and 100% release in 14 days. In vitro evaluation using human induced pluripotent stem cell-derived endothelial cells (hiPSC-ECs) showed cell viability and primitive network formation. In vivo subcutaneous injections showed host-vessel penetration into the delivered biomaterial within 4 days. Vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) loaded injections demonstrated an average lumen density of 80 +/- 15 vessels/mm 2 when compared to 4 +/- 1 vessels/mm 2 in the unloaded controls. In conclusion, we have designed a biomaterial system for disparate delivery models and shown successful vascularization of the biomaterial, demonstrating the versatile vascular regenerative capabilities of the hydrogel design.

Polyelectrolyte Complex Hydrogels with Controlled Mechanics Affect Mesenchymal Stem Cell Differentiation Relevant to Growth Plate Injuries.

The growth plate is a complex cartilage structure in long bones that mediates growth in children. When injured, the formation of a "bony bar" can occur which impedes normal growth and can cause angular deformities or growth arrest. Current treatments for growth plate injuries are limited and result in poor patient outcomes, necessitating research toward novel treatments that can prevent bony bar formation and stimulate cartilage regeneration. This study investigates alginate-chitosan polyelectrolyte complex (PEC) hydrogels as an injectable biomaterial system to prevent bony bar formation. Biomaterial properties including stiffness and degradation are quantified, and the effect that material properties have on mesenchymal stem cell (MSC) fate is quantified in vitro. Specifically, this study aims to elucidate the effectiveness of biomaterial-based control over the differentiation behavior of MSCs toward osteogenic or chondrogenic lineages using biochemical metabolite assays and quantitative real time PCR. Further, the PEC hydrogels are employed in a rat growth plate injury model to determine their effectiveness in preventing bony bar formation in vivo. Results indicate that hydrogel composition and material properties affect the differentiation tendency of MSCs in vitro, and the PEC hydrogels show promise as an injectable biomaterial for growth plate injuries.

Hydrogel-Embedded Poly(Lactic-co-Glycolic Acid) Microspheres for the Delivery of hMSC-Derived Exosomes to Promote Bioactive Annulus Fibrosus Repair.

ObjectiveIntervertebral disk degeneration is a prevalent postoperative complication after discectomy, underscoring the need to develop preventative and bioactive treatment strategies that decelerate degeneration and seal annulus fibrosus (AF) defects. Human mesenchymal stem cell–derived exosomes (MSC-Exos) hold promise for cell-free bioactive repair; however, their ability to promote AF repair is poorly understood. The objective of this study was to evaluate the ability of MSC-Exos to promote endogenous AF repair processes and integrate MSC-Exos within a biomaterial delivery system.DesignWe characterize biophysical and biochemical properties of normoxic (Nx) and hypoxic (Hx) preconditioned MSC-Exos from young, healthy donors and examine their effects on AF cell proliferation, migration, and gene expression. We then integrate a poly(lactic-co-glycolic acid) microsphere (PLGA µSphere) delivery platform within an interpenetrating network hydrogel to facilitate sustained MSC-Exo delivery.ResultsHx MSC-Exos led to a more robust response in AF cell proliferation and migration than Nx MSC-Exos and was selected for a downstream protection experiment. Hx MSC-Exos maintained a healthy AF cell phenotype under a TNFα challenge in vitro and attenuated catabolic responses. In all functional assays, AF cell responses were more sensitive to Hx MSC-Exos than Nx MSC-Exos. PLGA µSpheres released MSC-Exos over a clinically relevant timescale without affecting hydrogel modulus or pH upon initial embedment and µSphere degradation.ConclusionsThis MSC-Exo treatment strategy may offer benefits of stem cell therapy without the need for exogenous stem cell transplantation by stimulating cell proliferation, promoting cell migration, and protecting cells from the degenerative proinflammatory microenvironment.

Engineered Hemostatic Biomaterials for Sealing Wounds

Hemostatic biomaterials show great promise in wound control for the treatment of uncontrolled bleeding associated with damaged tissues, traumatic wounds, and surgical incisions. A surge of interest has been directed at boosting hemostatic properties of bioactive materials via mechanisms triggering the coagulation cascade. A wide variety of biocompatible and biodegradable materials has been applied to the design of hemostatic platforms for rapid blood coagulation. Recent trends in the design of hemostatic agents emphasize chemical conjugation of charged moieties to biomacromolecules, physical incorporation of blood-coagulating agents in biomaterials systems, and superabsorbing materials in either dry (foams) or wet (hydrogel) states. In addition, tough bioadhesives are emerging for efficient and physical sealing of incisions. In this Review, we highlight the biomacromolecular design approaches adopted to develop hemostatic bioactive materials. We discuss the mechanistic pathways of hemostasis along with the current standard experimental procedures for characterization of the hemostasis efficacy. Finally, we discuss the potential for clinical translation of hemostatic technologies, future trends, and research opportunities for the development of next-generation surgical materials with hemostatic properties for wound management.

Shape Memory Polymer Foams with Phenolic Acid-Based Antioxidant Properties.

Phenolic acids (PAs) are natural antioxidant agents in the plant kingdom that are part of the human diet. The introduction of naturally occurring PAs into the network of synthetic shape memory polymer (SMP) polyurethane (PU) foams during foam fabrication can impart antioxidant properties to the resulting scaffolds. In previous work, PA-containing SMP foams were synthesized to provide materials that retained the desirable shape memory properties of SMP PU foams with additional antimicrobial properties that were derived from PAs. Here, we explore the impact of PA incorporation on SMP foam antioxidant properties. We investigated the antioxidant effects of PA-containing SMP foams in terms of in vitro oxidative degradation resistance and cellular antioxidant activity. The PA foams showed surprising variability; p-coumaric acid (PCA)-based SMP foams exhibited the most potent antioxidant properties in terms of slowing oxidative degradation in H2O2. However, PCA foams did not effectively reduce reactive oxygen species (ROS) in short-term cellular assays. Vanillic acid (VA)- and ferulic acid (FA)-based SMP foams slowed oxidative degradation in H2O2 to lesser extents than the PCA foams, but they demonstrated higher capabilities for scavenging ROS to alter cellular activity. All PA foams exhibited a continuous release of PAs over two weeks. Based on these results, we hypothesize that PAs must be released from SMP foams to provide adequate antioxidant properties; slower release may enable higher resistance to long-term oxidative degradation, and faster release may result in higher cellular antioxidant effects. Overall, PCA, VA, and FA foams provide a new tool for tuning oxidative degradation rates and extending potential foam lifetime in the wound. VA and FA foams induced cellular antioxidant activity that could help promote wound healing by scavenging ROS and protecting cells. This work could contribute a wound dressing material that safely releases antimicrobial and antioxidant PAs into the wound at a continuous rate to ideally improve healing outcomes. Furthermore, this methodology could be applied to other oxidatively degradable biomaterial systems to enhance control over degradation rates and to provide multifunctional scaffolds for healing.

Advances in Stem Cell Therapies for Rotator Cuff Injuries.

Rotator cuff injury is a common upper extremity musculoskeletal disease that may lead to persistent pain and functional impairment. Despite the clinical outcomes of the surgical procedures being satisfactory, the repair of the rotator cuff remains problematic, such as through failure of healing, adhesion formation, and fatty infiltration. Stem cells have high proliferation, strong paracrine action, and multiple differentiation potential, which promote tendon remodeling and fibrocartilage formation and increase biomechanical strength. Additionally, stem cell-derived extracellular vesicles (EVs) can increase collagen synthesis and inhibit inflammation and adhesion formation by carrying regulatory proteins and microRNAs. Therefore, stem cell-based therapy is a promising therapeutic strategy that has great potential for rotator cuff healing. In this review, we summarize the advances of stem cells and stem cell-derived EVs in rotator cuff repair and highlight the underlying mechanism of stem cells and stem cell-derived EVs and biomaterial delivery systems. Future studies need to explore stem cell therapy in combination with cellular factors, gene therapy, and novel biomaterial delivery systems.

Immunological response of polysaccharide nanogel-incorporating PEG hydrogels in an in vivo diabetic model

Cell-based therapies hold significant advantages in comparison with the traditional drug-based or injection-based treatments. However, for long-term functional cellular implants, immune acceptance must be established. To accomplish the acceptance of the implanted cells, various biomaterial systems have been studied. Nanogels have shown great potential for modulation of cellular microenvironments, acting as a physical barrier between the immune system and the implant. However, internalization of nano-scale materials by implanted cells is not desirable and is yet to be overcome. In this study, we incorporated acrylate modified cholesterol-bearing pullulan (CHPOA) nanogels into poly (ethylene glycol) diacrylate (PEGDA) hydrogels through covalent crosslinking, where we used visible light-induced photopolymerization. We characterized morphology and swelling properties of CHPOA incorporated PEG composite hydrogels using FE-SEM and gravimetric analysis. Also, we investigated the biocompatibility properties of composite hydrogels in vivo, where we used both healthy and diabetic mice. We induced diabetes in mice using a low dose streptozotocin (STZ) injections and implanted composite hydrogels in both diabetic and healthy mice through subcutaneous route. Immune cell infiltration of the retrieved tissue was examined through histological analysis, where we observed minimum immune response levels of 0–2 rareness, according to ISO standard of biological evaluation of medical devices. Our observation suggests that the composite hydrogel developed here can be used to introduce nanostructured domains into bulk hydrogels and that this system has potential to be used as immunologically acceptable composite material in cellular therapy without internalization of nanoparticles.

Potential soluble substrates for transient electronics applications: A review

The excessive usage and demand of consumer electronics have caused an elevation of electronic waste. Typically, consumer electronics are produced with non-biodegradable, non-biostable, and sometimes fatal materials, resulting in global alarming biological summons. Thence, to mend the drawbacks, an emerging field—named transient electronics—takes effect where the biomaterial, device, substrate, and total systems disappear untraceably after steady-state operation. Conspicuously, transient electronics have induced immense curiosity in researchers to perform interesting investigations due to the feature of disintegration after stable operation. The idea of transient electronics has been implemented in biomedical, military, and nanotechnology fields. Although rapid development is evident in transient technology in a short period, it is believed that the technology will deliver the utmost prospects in advanced electronic applications. Essentially, in transient technology, the vital challenge is to determine the platform materials that offer stability, resistance, biocompatibility, and mainly, the solubility to accommodate the transient devices. In this Review, a detailed overview of different soluble substrates, such as organic, polymer, and solid-state substrates, is described, along with the feasibility of the fabricated devices on the respective substrates to support transient electronics. Second, the dissolving mechanism of the corresponding substrates is analyzed.

In Vitro Study of Hyaluronic Acid Based Scaffolds and Its Effect on Cartilage Regeneration

Recently, it has been proven that cartilage healing is difficult. The most commonly used treatments are autogenously cartilage grafting and allogeneic bone grafting, but grafts cannot fully meet treatment goals because of source, price, safety, and other concerns. Thus, a combination of biological materials and tissue engineering technology has become a recent trend in studies. Among the studies performed on tissue engineering cartilage materials are hydrogels that exhibit biological activity, post-decomposition adsorption, flexibility, and easy preparation. Cell-containing hydrogels are often used in cartilage tissue engineering because of their biocompatibility, ease of use, and ability to adapt to different defects. Hydrogels are used to mimic extracellular matrices. Although multiple materials can configure and form hydrogels, hyaluronic acid and its derivatives are distinguished. Hyaluronic acid (HA) is an extracellular molecule with several physical and biological functions found in many tissues, including cartilage. HA is formed in several biomaterial systems and scaffolding. HA hydrogels have many interests, including increased adhesion, cell proliferation, and wound healing. In addition, they represent adequate biological acting for stimulating a microenvironment for the survival of cells. However, their disadvantages include a slow degradation rate and low mechanical properties. Here, HA-based hydrogels and their applications in cartilage tissue engineering are briefly reviewed.