Carrier Biomaterials Research Articles

Molecular mechanism of plant elicitor daphnetin-carboxymethyl chitosan nanoparticles against Ralstonia solanacearum by activating plant system resistance

The exploration of biopolymer-based materials to avoid hazardous chemicals in agriculture has gained enormous importance for sustainable crop protection. Due to its good biocompatibility and water solubility, carboxymethyl chitosan (CMCS) has been widely applied as a pesticide carrier biomaterial. However, the mechanism by which carboxymethyl chitosan-grafted natural product nanoparticles induce tobacco systemic resistance against bacterial wilt remains largely unknown. In this study, water-soluble CMCS-grafted daphnetin (DA) nanoparticles (DA@CMCS-NPs) were successfully synthesized, characterized, and assessed for the first time. The grafting rate of DA in CMCS was 10.05 %, and the water solubility was increased. In addition, DA@CMCS-NPs significantly increased the activities of CAT, PPO and SOD defense enzymes, activated the expression of PR1 and NPR1, and suppressed the expression of JAZ3. DA@CMCS-NPs could induce immune responses against R. solanacearum in tobacco, including increases in defense enzymes and overexpression of pathogenesis-related (PR) proteins. The application of DA@CMCS-NPs effectively suppressed the development of tobacco bacterial wilt in pot experiments, and the control efficiency was as high as 74.23 %, 67.80 %, 61.67 % at 8, 10, and 12 days after inoculation. Additionally, DA@CMCS-NPs has excellent biosafety. Therefore, this study highlighted the application of DA@CMCS-NPs in manipulating tobacco to generate defense responses against R. solanacearum, which can be attributed to systemic resistance.

Mesenchymal Stromal/Stem Cell (MSC)-Based Vector Biomaterials for Clinical Tissue Engineering and Inflammation Research: A Narrative Mini Review.

Mesenchymal stromal/stem cells (MSCs) have the ability of self-renewal, the potential of multipotent differentiation, and a strong paracrine capacity, which are mainly used in the field of clinical medicine including dentistry and orthopedics. Therefore, tissue engineering research using MSCs as seed cells is a current trending directions. However, the healing effect of direct cell transplantation is unstable, and the paracrine/autocrine effects of MSCs cannot be effectively elicited. Tumorigenicity and heterogeneity are also concerns. The combination of MSCs as seed cells and appropriate vector materials can form a stable cell growth environment, maximize the secretory features of stem cells, and improve the biocompatibility and mechanical properties of vector materials that facilitate the delivery of drugs and various secretory factors. There are numerous studies on tissue engineering and inflammation of various biomaterials, mainly involving bioceramics, alginate, chitosan, hydrogels, cell sheets, nanoparticles, and three-dimensional printing. The combination of bioceramics, hydrogels and cell sheets with stem cells has demonstrated good therapeutic effects in clinical applications. The application of alginate, chitosan, and nanoparticles in animal models has also shown good prospects for clinical applications. Three-dimensional printing technology can circumvent the shortage of biomaterials, greatly improve the properties of vector materials, and facilitate the transplantation of MSCs. The purpose of this narrative review is to briefly discuss the current use of MSC-based carrier biomaterials to provide a useful resource for future tissue engineering and inflammation research using stem cells as seed cells.

Bioprocessing by Decellularized Scaffold Biomaterials in Cultured Meat: A Review.

As novel carrier biomaterials, decellularized scaffolds have promising potential in the development of cellular agriculture and edible cell-cultured meat applications. Decellularized scaffold biomaterials have characteristics of high biocompatibility, bio-degradation, biological safety and various bioactivities, which could potentially compensate for the shortcomings of synthetic bio-scaffold materials. They can provide suitable microstructure and mechanical support for cell adhesion, differentiation and proliferation. To our best knowledge, the preparation and application of plant and animal decellularized scaffolds have not been summarized. Herein, a comprehensive presentation of the principles, preparation methods and application progress of animal-derived and plant-derived decellularized scaffolds has been reported in detail. Additionally, their application in the culture of skeletal muscle, fat and connective tissue, which constitute the main components of edible cultured meat, have also been generally discussed. We also illustrate the potential applications and prospects of decellularized scaffold materials in future foods. This review of cultured meat and decellularized scaffold biomaterials provides new insight and great potential research prospects in food application and cellular agriculture.

De novo engineering of both an omega-3 fatty acid-derived nanocarrier host and a prodrug guest to potentiate drug efficacy against colorectal malignancies

Drug-carrier compatibility impacts drug delivery efficiency and resulting therapeutic efficacy and tolerability. Although numerous biodegradable carrier materials have been pursued over the past decades, chemical strategies that are sought to tailor therapeutic structures and their carriers together in a concerted effort remain rare yet may be powerful. Based on the principle of improving the structural similarity between these central components, we developed an omega-3 fatty acid-conjugated poly(ethylene glycol) (PEG) nanocarrier host that is capable of supramolecular assembly of a cytotoxic prodrug guest. To demonstrate the proof of concept, we ligated two docosahexaenoic acid (DHA) molecules and one PEG chain via a d-lysine linkage to produce an amphiphilic matrix DHA2-PEG, which is suited for the encapsulation of active compounds, including a DHA monoconjugated camptothecin prodrug. The resulting DHA2-PEG-cloaked nanoassemblies show superior stability and rapid cellular uptake compared with those formulated in clinically approved materials. In a chemically induced mouse model of colitis-associated colorectal cancer, administration of the camptothecin nanoassemblies demonstrated notable inhibition of colon tumor growth. Furthermore, this new delivery platform has low systemic toxicity and immunotoxicity in animals and is appealing for further investigation and clinical translation. Thus, through rational engineering of the carrier biomaterials and drug derivatization, the in vivo performance of drug delivery systems can be improved. This approach also establishes a methodology for leveraging synthetic chemistry tools to optimize delivery systems for a broad range of drug classes.

PH-Responsive Eco-Friendly Chitosan–Chlorella Hydrogel Beads for Water Retention and Controlled Release of Humic Acid

For improving the mechanical strength of controlled release fertilizer (CRF) hydrogels, a novel material of Chlorella was employed as a bio-based filler to prepare chitosan–chlorella hydrogel beads with physical crosslink method. Here, the synthesis mechanism was investigated, and the chitosan–chlorella hydrogel beads exhibited enhanced mechanical stability under centrifugation and sonication than pure chitosan hydrogel beads. Chlorella brought more abundant functional groups to original chitosan hydrogel, hence, chitosan–chlorella hydrogel beads represented greater sensitivity and controllable response to external factors including pH, salt solution, temperature. In distilled water, the hydrogel beads with 40 wt% Chlorella reached the largest water absorption ratio of 42.92 g/g. Moreover, the mechanism and kinetics process of swelling behavior of the chitosan–chlorella hydrogel beads were evaluated, and the loading and releasing of humic acid by the hydrogel beads as a carrier material were pH-dependent and adjustable, which exhibit the potential of chitosan–chlorella hydrogel beads in the field of controlled release carrier biomaterials.

Antimicrobial and anti-inflammatory thermo-reversible hydrogel for periodontal delivery

In periodontal treatment, topical adjunctive therapy with antimicrobials or anti-inflammatory agents is frequently applied. However, currently available drug carrier biomaterials often exhibit poor perfusion into small crevices, such as the deep and irregular periodontal pockets, due to relatively high viscosity. Moreover, high polymer concentrations of the polymer can potentially be cytotoxic upon confined local administration. This study aimed to formulate an antimicrobial and anti-inflammatory treatment option, by incorporating doxycycline (DOX) and/or lipoxin A4 (LXA4) into 0.5 wt% thermo-reversible polyisocyanopeptide (PIC). PIC can form hydrogels upon low polymer concentration, and we hypothesized that the thermo-reversible nature of the material would allow for application into the periodontal pocket. The formulations were characterized in vitro and finally tested in dogs with naturally occurring periodontitis, which were not euthanized afterward. Results showed that PIC/DOX/LXA4 hydrogel could be easily prepared and injected into periodontal pockets. The PIC hydrogel facilitated the release of DOX or LXA4 for around 4 days in vitro. When applied in dogs, the hydrogel exerted no local or systemic adverse effects. Gels loaded with LXA4 and/or DOX reduced the subgingival bacterial load and pro-inflammatory interleukin-8 level. In addition, PIC-DOX and PIC-DOX+LXA4 improved gingival clinical attachment by 0.6 mm compared with conventional periodontal treatment alone (i.e. mechanical debridement). In conclusion, the thermo-reversible PIC hydrogel is a safe and effective vehicle for periodontal drug delivery.

Synthesis, Characterization and In Vitro Evaluation of Dual pH/Redox Sensitive Marine Laminarin-Based Nanomedicine Carrier Biomaterial for Cancer Therapy.

In order to improve the anti-cancer therapy efficiency of hydrophobic drugs such as curcumin (Cur), a novel dual pH/redox sensitive marine laminarin-based nanomedicine carrier biomaterial with photo-dynamic therapy (PDT) was synthesized in this study. The new synthetic chemical structure, named as Hematin-Laminarin-Dithiodipropionic Acid-MGK (HLDM), was characterized by 1H-NMR and IR. The Cur-loaded micelles were then prepared via dialysis method. The HLDM could self-assemble into micelles in water with hydrodynamic diameter of 135±15 nm. The particle size, zeta potential and morphology of micelles were detected by transmission electron microscope (TEM). Interestingly, the in vitro release experiment showed that the release amount of Cur-loaded HLDM micelles could reach 80% in the pH and redox sensitive environment. Furthermore, cell study showed that the Cur-loaded HLDM micelles had stronger cellular uptake and cytotoxicity to MCF-7 cells than that of HLDM. The multifunctional marine laminarin based nanomedicine carrier biomaterial can be used for new drug delivery systems with dual pH/redox sensitivity for cancer therapy.

Learning from Mother Nature: Innovative Tools to Boost Endogenous Repair of Critical or Difficult-to-Heal Large Tissue Defects.

For repair of chronic or difficult-to-heal tissue lesions and defects, major constraints exist to a broad application of cell therapy and tissue engineering approaches, i.e., transplantation of “ex vivo” expanded autologous stem/progenitor cells, alone or associated with carrier biomaterials. To enable a large number of patients to benefit, new strategies should be considered. One of the main goals of contemporary regenerative medicine is to develop new regenerative therapies, inspired from Mother Nature. In all injured tissues, when platelets are activated by tissue contact, their released factors promote innate immune cell migration to the wound site. Platelet-derived factors and factors secreted by migrating immune cells create an inflammatory microenvironment, in turn, causing the activation of angiogenesis and vasculogenesis processes. Eventually, repair or regeneration of the injured tissue occurs via paracrine signals activating, mobilizing or recruiting to the wound site cells with healing potential, such as stem cells, progenitors, or undifferentiated cells derived from the reprogramming of tissue differentiated cells. This review, largely based on our studies, discusses the identification of new tools, inspired by cellular and molecular mechanisms overseeing physiological tissue healing, that could reactivate dormant endogenous regeneration mechanisms lost during evolution and ontogenesis.

Biologics and Cell Therapy Tissue Engineering Approaches for the Management of the Edentulous Maxilla: A Systematic Review.

The aim of this systematic review was to evaluate current and emerging regenerative approaches for implant site development in the edentulous atrophic maxilla using tissue engineering and regenerative medicine (TERM) principles and to identify priorities for future research. Two independent examiners conducted a comprehensive search using specific keywords to identify original clinical studies using TERM for implant site development in the edentulous atrophic maxilla including indications for alveolar ridge preservation, horizontal alveolar augmentation, maxillary sinus augmentation, and augmentation of severe vertical or combined defects. Endpoints included clinical, radiographic, histologic, and patient-centered outcomes. The initial search identified 3,061 articles. The final selection included 89 articles, of which 12 evaluated alveolar ridge preservation, 6 horizontal defects, 61 maxillary sinus augmentation, and 11 management of severe vertical or combined defects. A summary of the main findings relative to the effect of TERM-based approaches applied for implant site development in the atrophic maxillary segments is presented. Marked heterogeneity among included studies prevented meaningful quantitative analysis. The following relevant effects of TERM-based therapies for site development in the edentulous atrophic maxilla were observed: (1) recombinant human bone morphogenetic protein-2 in an absorbable collagen sponge carrier increased bone augmentation; (2) recombinant human platelet-derived growth factor BB in combination with freeze-dried bone allograft or beta tricalcium phosphate accelerated bone formation through accelerated remodeling of carrier biomaterials; (3) autologous cell therapy enhanced clinical and radiographic outcomes; (4) autologous cell therapy in alveolar ridge preservation provided superior histomorphometric outcomes (vital bone formation) at 6 weeks; and (5) platelet-rich plasma formulations combined with autologous bone grafts for maxillary sinus augmentation increased radiographic density and accelerated bone mineralization at 6 months. Clinical success has been demonstrated with the application of different TERM modalities for implant site development in the edentulous atrophic maxilla. However, indications are narrow and further study is needed. Clinical trials assessing meaningful outcomes, involving larger populations, and with longer follow-up are warranted to discern the effectiveness of the achieved results compared with a valid control.

Mechanically resilient, injectable, and bioadhesive supramolecular gelatin hydrogels crosslinked by weak host-guest interactions assist cell infiltration and in situ tissue regeneration.

Although considered promising materials for assisting organ regeneration, few hydrogels meet the stringent requirements of clinical translation on the preparation, application, mechanical property, bioadhesion, and biocompatibility of the hydrogels. Herein, we describe a facile supramolecular approach for preparing gelatin hydrogels with a wide array of desirable properties. Briefly, we first prepare a supramolecular gelatin macromer via the efficient host-guest complexation between the aromatic residues of gelatin and free diffusing photo-crosslinkable acrylated β-cyclodextrin (β-CD) monomers. The subsequent crosslinking of the macromers produces highly resilient supramolecular gelatin hydrogels that are solely crosslinked by the weak host-guest interactions between the gelatinous aromatic residues and β-cyclodextrin (β-CD). The obtained hydrogels are capable of sustaining excessive compressive and tensile strain, and they are capable of quick self healing after mechanical disruption. These hydrogels can be injected in the gelation state through surgical needles and re-molded to the targeted geometries while protecting the encapsulated cells. Moreover, the weak host-guest crosslinking likely facilitate the infiltration and migration of cells into the hydrogels. The excess β-CDs in the hydrogels enable the hydrogel-tissue adhesion and enhance the loading and sustained delivery of hydrophobic drugs. The cell and animal studies show that such hydrogels support cell recruitment, differentiation, and bone regeneration, making them promising carrier biomaterials of therapeutic cells and drugs via minimally invasive procedures.

Gallic acid grafting effect on delivery performance and antiglaucoma efficacy of antioxidant-functionalized intracameral pilocarpine carriers

Functionalization of therapeutic carrier biomaterials can potentially provide additional benefits in drug delivery for disease treatment. Given that this modification determines final therapeutic efficacy of drug carriers, here, we investigate systematically the role of grafting amount of antioxidant gallic acid (GA) onto GN in situ gelling copolymers made of biodegradable gelatin and thermo-responsive poly(N-isopropylacrylamide) for intracameral delivery of pilocarpine in antiglaucoma treatment. As expected, increasing redox reaction time increased total antioxidant activities and free radical scavenging abilities of synthesized carrier biomaterials. The hydrophilic nature of antioxidant molecules strongly affected physicochemical properties of carrier materials with varying GA grafting amounts, thereby dictating in vitro release behaviors and mechanisms of pilocarpine. In vitro oxidative stress challenges revealed that biocompatible carriers with high GA content alleviated lens epithelial cell damage and reduced reactive oxygen species. Intraocular pressure and pupil diameter in glaucomatous rabbits showed correlations with GA-mediated release of pilocarpine. Additionally, enhanced pharmacological treatment effects prevented corneal endothelial cell loss during disease progression. Increasing GA content increased total antioxidant level and decreased nitrite level in the aqueous humor, suggesting a much improved antioxidant status in glaucomatous eyes. This work significantly highlights the dependence of physicochemical properties, drug release behaviors, and bioactivities on intrinsic antioxidant capacities of therapeutic carrier biomaterials for glaucoma treatment. Statement of SignificanceDevelopment of injectable biodegradable polymer depots and functionalization of carrier biomaterials with antioxidant can potentially provide benefits such as improved bioavailability, controlled release pattern, and increased therapeutic effect in intracameral pilocarpine administration for glaucoma treatment. For the first time, this study demonstrated that the biodegradable in situ gelling copolymers can incorporate different levels of antioxidant gallic acid to tailor the structure-property-function relationship of the intracameral drug delivery system. The systematic evaluation fully verified the dependence of phase transition, degradation behavior, drug release mechanism, and antiglaucoma efficacy on intrinsic antioxidant capacities of carrier biomaterials. The report highlights the significant role of grafting amount of gallic acid in optimizing performance of antioxidant-functionalized polymer therapeutics as new drug delivery platforms in disease treatment.

Differential response of encapsulated nucleus pulposus and bone marrow stem cells in isolation and coculture in alginate and chitosan hydrogels.

Cell-based therapies may hold significant promise for the treatment of early stage degeneration of the intervertebral disc (IVD). Given their propensity to proliferate and ability to form multiple tissue types, mesenchymal stem cells (MSCs) have been proposed as a potential cell source to promote repair of the nucleus pulposus (NP). However, for any successful cell-based therapy, a carrier biomaterial may be essential for targeted delivery providing key biophysical and biochemical cues to facilitate differentiation of MSCs. Two widely used biomaterials for NP regeneration are chitosan and alginate. The primary objective of this study was to assess the influence of alginate and chitosan hydrogels on bone marrow stem cells (BM) and NP cells in isolation or in coculture. A secondary objective of this study was to investigate coculture seeding density effects of BM and NP cells and simultaneously explore which cell type is responsible for matrix formation in a cocultured environment. Porcine NP and BM cells were encapsulated in alginate and chitosan hydrogels separately at two seeding densities (4×10(6) and 8×10(6) cells/mL) or in coculture (1:1, 8×10(6) cells/mL). Constructs (diameter=5 mm, height=3 mm) were maintained under IVD-like conditions [low-glucose, low (5%) oxygen] with or without transforming growth factor-β3 (TGF-β3) supplementation for 21 days. Results demonstrated differential viability depending on hydrogel type. NP cells remained viable in both biomaterial types whereas BM viability was diminished in chitosan. Further, hydrogel type was found to regulate sulfated glycosaminoglycan (sGAG) and collagen accumulation. Specifically, alginate better supports sGAG accumulation and collagen type II deposition for both NP and BM cell types compared with chitosan. Having identified that alginate more readily supports cell viability and matrix accumulation, we further explored additional effects of seeding density ratios (NP:BM--1:1, 1:2) for coculture studies. Interestingly, in coculture conditions, the BM cell population declined in number while NP cells increased, indicating that MSCs may in fact be signaling NP cells to proliferate rather than contributing to matrix formation. These findings provide exciting new insights on the potential of MSCs for NP tissue regeneration strategies.

Induction of mesenchymal stem cell differentiation and cartilage formation by cross-linker-free collagen microspheres.

Because of poor self-healing ability, joint cartilage can undergo irreversible degradation in the course of various diseases or after injury. A promising approach for cartilage engineering consists of using of mesenchymal stem cells (MSC) and a differentiation factor combined with an injectable carrier biomaterial. We describe here a novel synthesis route for native collagen microspheres that does not involve the use of potentially toxic crosslinking agents. An emulsion was formed between a type I collagen solution and perfluorinated oil, stabilised by a biocompatible triblock perfluorinated copolymer surfactant. Spherical microparticles of fibrillar collagen were formed through a sol-gel transition induced by ammonia vapours. Electron microscopy observations showed that these self-cross-linked microspheres were constituted by a gel of striated collagen fibrils. Microspheres that were loaded with transforming growth factor beta (TGF-β)3 progressively released this differentiation factor over a four weeks period. Human MSC rapidly adhered to TGF-β3-loaded microspheres and, after 21d of culture, exhibited typical chondrocyte morphology and produced an uncalcified matrix made of the predominant cartilage components, aggrecan and type II collagen, but devoid of the hypertrophic marker type X collagen. Subcutaneous co-injection of MSC and TGF-β3-loaded microspheres in mice consistently led to the formation of a cartilage-like tissue, which was however hypertrophic, calcified and vascularised. In conclusion, we developed cross-linker free collagen microspheres that allowed chondrogenic differentiation of MSC in vitro and in vivo.

Long‐term cell‐mediated protein release from calcium phosphate ceramics

Efficient delivery of growth factors from carrier biomaterials depends critically on the release kinetics of the proteins that constitute the carrier. Immobilizing growth factors to calcium phosphate ceramics has been attempted by direct adsorption and usually resulted in a rapid and passive release of the superficially adherent proteins. The insufficient retention of growth factors limited their bioavailability and their efficacy in the treatment of bone regeneration. In this study, a coprecipitation technique of proteins and calcium phosphate was employed to modify the delivery of proteins from biphasic calcium phosphate (BCP) ceramics. To this end, tritium-labeled bovine serum albumin ([(3)H]BSA) was utilized as a model protein to analyze the coprecipitation efficacy and the release kinetics of the protein from the carrier material. Conventional adsorption of [(3)H]BSA resulted in a rapid and passive release of the protein from BCP ceramics, whereas the coprecipitation technique effectively prevented the burst release of [(3)H]BSA. Further analysis of the in vitro kinetics demonstrated a sustained, cell-mediated release of coprecipitated [(3)H]BSA from BCP ceramics induced by resorbing osteoclasts. The coprecipitation technique described herein, achieved a physiologic-like protein release, by incorporating [(3)H]BSA into its respective carriers, rendering it a promising tool in growth factor delivery for bone healing.

MicroCT Evaluation of Three-Dimensional Mineralization in Response to BMP-2 DosesIn Vitroand in Critical Sized Rat Calvarial Defects

Numerous growth factors, peptides, and small molecules are being developed for bone tissue engineering. The optimal dosing, stability, and bioactivity of these biological molecules are likely influenced by the carrier biomaterial. Efficient evaluation of various formulations will require objective evaluation of in vitro culture systems and in vivo regeneration models. The objective of this paper is to examine the utility of microcomputed tomography (microCT) over conventional techniques in the evaluation of the bone morphogenetic protein-2 (BMP-2) dose response effect in a three-dimensional (3D) in vitro culture system and in an established calvarial defect model. Cultured MC3T3-E1 osteoblasts displayed increased cellular density, extracellular matrix (ECM) production, and mineralization on 3D poly(lactic-co-glycolic acid) (PLGA) scaffolds in a BMP-2 dose dependent manner. MicroCT revealed differences in shape and spatial organization of mineralized areas, which would not have been possible through conventional alizarin red staining alone. Additionally, BMP-2 (doses of 30 to 240 ng/mm(3)) was grafted into 5 mm critical sized rat calvarial defects, where increased bone regeneration was observed in a dose dependent manner, with higher doses of BMP-2 inducing greater bone area, volume, and density. The data revealed the utility of microCT analysis as a beneficial addition to existing techniques for objective evaluation of bone tissue engineering and regeneration.

Carboxymethylcellulose-stabilized collagenous rhOP-1 device-a novel carrier biomaterial for the repair of mandibular continuity defects.

Human recombinant osteogenic protein-1 (rhOP-1) is osteoinductive. Efforts are made to develop carrier biomaterials with improved space-keeping properties. Bovine collagen type I matrix charged with rhOP-1 was suggested to be an advantageous device of relative liquid quality. We hypothesized that the addition of carboxymethylcellulose (CMC) may stabilize the device and facilitate the regeneration of mandibular continuity defects without further addition of mineralized carrier materials. To test this hypothesis, the anatomical shape, functional remodeling, and mechanical stability of such bony regenerates were evaluated in the course of an animal experiment. Mandibular continuity defects of 5 cm in size were created in five Göttingen minipigs on one side (contralateral hemimandible: control) and bridged with titanium plates. Four animals were treated with the rhOP-1 device (3000 microg rhOP-1, 2 g collagen, 1 g CMC), and one animal was treated with a placebo device omitting rhOP-1. After 12 weeks of experimental period, bony continuity was reestablished in rhOP-1-treated hemimandibles. The bony regenerates were of good anatomical shape, volume, and functional remodeling. Placebo treatment led to insufficient bony regenerates of significant lower bone volume (volume in 3D-CT scan 29.81 cm(3) vs 8.85 cm(3)). To produce 1 mm of bending, 1972 N were needed for rhOP-1-treated hemimandibles, 2617 N for control hemimandibles, and 642 N for the placebo treated hemimandible. CMC stabilization of collagen carrier biomaterials for rhOP-1 provides good plasticity as well as excellent space-keeping properties and may not interfere with osteoinduction. The results of this preliminary study suggest that the applied rhOP-1 device offers a potential option for further studies on the reconstruction of mandibular defects.