An adhesive bone marrow scaffold and bone morphogenetic-2 protein carrier for cartilage tissue engineering

Advances in mechanically robust and biomimetic polysaccharide-based constructs for cartilage tissue engineering

The purpose of cartilage tissue engineering is to provide artificial constructs with biological functions and mechanical features that resemble native tissue to improve tissue regeneration. Biochemical characteristics of the cartilage extracellular matrix (ECM) microenvironment provide a platform for researchers to develop biomimetic materials for optimal tissue repair. Due to the structural similarity of polysaccharides into physicochemical characteristics of cartilage ECM, these natural polymers capture special attention for developing biomimetic materials. The mechanical properties of constructs play a crucial influence in load-bearing cartilage tissues. Moreover, the addition of appropriate bioactive molecules to these constructs can promote chondrogenesis. Here, we discuss polysaccharide-based constructs that can be used to create substitutes for cartilage regeneration. We intend to focus on newly developed bioinspired materials, fine-tuning the mechanical properties of constructs, the design of carriers loaded by chondroinductive agents, and development of appropriate bioinks as a bioprinting approach for cartilage regeneration.

Progress of 3D Printing Techniques for Nasal Cartilage Regeneration

Once cartilage is damaged, its self-repair capacity is very limited. The strategy of tissue engineering has brought a new idea for repairing cartilage defect and cartilage regeneration. In particular, nasal cartilage regeneration is a challenge because of the steady increase in nasal reconstruction after oncologic resection, trauma, or rhinoplasty. From this perspective, three-dimensional (3D) printing has emerged as a promising technology to address the complexity of nasal cartilage regeneration, using patient's image data and computer-aided deposition of cells and biomaterials to precisely fabricate complex, personalized tissue-engineered constructs. In this review, we summarized the major progress of three prevalent 3D printing approaches, including inkjet-based printing, extrusion-based printing and laser-assisted printing. Examples are highlighted to illustrate 3D printing for nasal cartilage regeneration, with special focus on the selection of seeded cell, scaffolds and growth factors. The purpose of this paper is to systematically review recent research about the challenges and progress and look forward to the future of 3D printing techniques for nasal cartilage regeneration.Level of Evidence III This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors https://www.springer.com/00266 .

Sustained protein therapeutics enabled by self-healing nanocomposite hydrogels for non-invasive bone regeneration

The self-healing nanocomposite hydrogel for sustained release of BMP-2 to enhance bone regeneration.

Hydrogels for Cartilage Regeneration, from Polysaccharides to Hybrids

The aims of this paper are: (1) to review the current state of the art in the field of cartilage substitution and regeneration; (2) to examine the patented biomaterials being used in preclinical and clinical stages; (3) to explore the potential of polymeric hydrogels for these applications and the reasons that hinder their clinical success. The studies about hydrogels used as potential biomaterials selected for this review are divided into the two major trends in tissue engineering: (1) the use of cell-free biomaterials; and (2) the use of cell seeded biomaterials. Preparation techniques and resulting hydrogel properties are also reviewed. More recent proposals, based on the combination of different polymers and the hybridization process to improve the properties of these materials, are also reviewed. The combination of elements such as scaffolds (cellular solids), matrices (hydrogel-based), growth factors and mechanical stimuli is needed to optimize properties of the required materials in order to facilitate tissue formation, cartilage regeneration and final clinical application. Polymer combinations and hybrids are the most promising materials for this application. Hybrid scaffolds may maximize cell growth and local tissue integration by forming cartilage-like tissue with biomimetic features.

Hydrogel-Based Controlled Delivery Systems for Articular Cartilage Repair

Delivery of bioactive factors is a very valuable strategy for articular cartilage repair. Nevertheless, the direct supply of such biomolecules is limited by several factors including rapid degradation, the need for supraphysiological doses, the occurrence of immune and inflammatory responses, and the possibility of dissemination to nontarget sites that may impair their therapeutic action and raise undesired effects. The use of controlled delivery systems has the potential of overcoming these hurdles by promoting the temporal and spatial presentation of such factors in a defined target. Hydrogels are promising materials to develop delivery systems for cartilage repair as they can be easily loaded with bioactive molecules controlling their release only where required. This review exposes the most recent technologies on the design of hydrogels as controlled delivery platforms of bioactive molecules for cartilage repair.

Personalizing Biomaterials for Precision Nanomedicine Considering the Local Tissue Microenvironment

New advances in (nano)biomaterial design coupled with the detailed study of tissue-biomaterial interactions can open a new chapter in personalized medicine, where biomaterials are chosen and designed to match specific tissue types and disease states. The notion of a "one size fits all" biomaterial no longer exists, as growing evidence points to the value of customizing material design to enhance (pre)clinical performance. The complex microenvironment in vivo at different tissue sites exhibits diverse cell types, tissue chemistry, tissue morphology, and mechanical stresses that are further altered by local pathology. This complex and dynamic environment may alter the implanted material's properties and in turn affect its in vivo performance. It is crucial, therefore, to carefully study tissue context and optimize biomaterials considering the implantation conditions. This practice would enable attaining predictable material performance and enhance clinical outcomes.

Positive impact of IGF-1-coupled nanoparticles on the differentiation potential of human chondrocytes cultured on collagen scaffolds

PURPOSE

In the present study, silica nanoparticles (sNP) coupled with insulin-like growth factor 1 (IGF-1) were loaded on a collagen-based scaffold intended for cartilage repair, and the influence on the viability, proliferation, and differentiation potential of human primary articular chondrocytes was examined.

METHODS

Human chondrocytes were isolated from the hyaline cartilage of patients (n=4, female, mean age: 73±5.1 years) undergoing primary total knee joint replacement. Cells were dedifferentiated and then cultivated on a bioresorbable collagen matrix supplemented with fluorescent sNP coupled with IGF-1 (sNP-IGF-1). After 3, 7, and 14 days of cultivation, cell viability and integrity into the collagen scaffold as well as metabolic cell activity and synthesis rate of matrix proteins (collagen type I and II) were analyzed.

RESULTS

The number of vital cells increased over 14 days of cultivation, and the cells were able to infiltrate the collagen matrix (up to 120 μm by day 7). Chondrocytes cultured on the collagen scaffold supplemented with sNP-IGF-1 showed an increase in metabolic activity (5.98-fold), and reduced collagen type I (1.58-fold), but significantly increased collagen type II expression levels (1.53-fold; P=0.02) after 7 days of cultivation compared to 3 days. In contrast, chondrocytes grown in a monolayer on plastic supplemented with sNP-IGF-1 had significantly lower metabolic activity (1.32-fold; P=0.007), a consistent amount of collagen type I, and significantly reduced collagen type II protein expression (1.86-fold; P=0.001) after 7 days compared to 3 days.

CONCLUSION

Collagen-based scaffolds enriched with growth factors, such as IGF-1 coupled to nanoparticles, represent an improved therapeutic intervention for the targeted and controlled treatment of articular cartilage lesions.

Skeletal tissue regeneration: where can hydrogels play a role?

The emerging field of tissue engineering reveals promising approaches for the repair and regeneration of skeletal tissues including the articular cartilage, bone, and the entire joint. Amongst the myriad of biomaterials available to support this strategy, hydrogels are highly tissue mimicking substitutes and thus of great potential for the regeneration of functional tissues. This review comprises an overview of the novel and most promising hydrogels for articular cartilage, osteochondral and bone defect repair. Chondro- and osteo-conductive and -instructive hydrogels are presented, highlighting successful combinations with inductive signals and cell sources. Moreover, advantages, drawbacks, and future perspectives of the role of hydrogels in skeletal regeneration are addressed, pointing out the current state of this rising approach.

Design strategies of biodegradable scaffolds for tissue regeneration

There are numerous available biodegradable materials that can be used as scaffolds in regenerative medicine. Currently, there is a huge emphasis on the designing phase of the scaffolds. Materials can be designed to have different properties in order to match the specific application. Modifying scaffolds enhances their bioactivity and improves the regeneration capacity. Modifications of the scaffolds can be later characterized using several tissue engineering tools. In addition to the material, cell source is an important component of the regeneration process. Modified materials must be able to support survival and growth of different cell types. Together, cells and modified biomaterials contribute to the remodeling of the engineered tissue, which affects its performance. This review focuses on the recent advancements in the designs of the scaffolds including the physical and chemical modifications. The last part of this review also discusses designing processes that involve viability of cells.

Split of chiral degeneracy in mechanical and structural properties of oligopeptide-polysaccharide biomaterials

Enantiomeric biomaterials which are mirror images of each other are characterized by chiral degeneracy--identical structural characteristics and bulk material properties. The addition of another chiral component, D-polysaccharide, has been shown to split such degeneracy and result in two distinct biomaterials. Dynamic oscillatory rheometry and small-angle X-ray scattering demonstrate that the natural biochirality combination of L-peptides and D-polysaccharides assembles faster, has higher elastic moduli (G'), and is structurally more beneficial as opposed to the alternative D-peptide and D-polysaccharide combination. Chemical modifications of the OH-groups in α-D-glucose units in D-polysaccharides weaken such splitting of chiral degeneracy. These findings form a basis to design novel biomaterials and provide additional insight on why proteins and polysaccharides have oppoiste chirality in the biological world.