Preparation and characterization of 3D hydroxyapatite/collagen scaffolds and its application in bone regeneration with bone morphogenetic protein-2.

Desirable bone engineering materials should have a conducive three-dimensional (3D) structure and bioactive mediators for guided bone regeneration. In the present study, hydroxyapatite (HA)/collagen (Col) scaffolds were prepared by an optimized freeze-drying process. The porosity, moisture content, and mechanical properties of the composite have been investigated. The micro-morphology and structure were analyzed with scanning electron microscopy (SEM) and transmission electron microscopy (TEM), confirmed that self-cross-linked HA/Col was evenly distributed and formed a 3D porous scaffold. The physicochemical/mechanical characterization was carried out by Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). Morphological observation and CCK-8 assay of co-culture cells indicated that HA/Col scaffolds were biocompatible. Then HA/Col scaffolds coupled with recombinant human bone morphogenetic proteins 2 (rhBMP-2) were implanted in the mandibular critical size defect in rats, and histological staining was used to evaluate the bone reconstruction. The result showed that HA/Col coupled with rhBMP-2 could significantly improve the formation of new bone and angiogenesis within the scaffolds as well as the proliferation and differentiation of osteoblasts. Thanks to the encouraging osteogenesis effects, the well-defined 3D scaffolds (HA/Col) cooperating with bioactive agents (rhBMP-2) are expected to be a promising candidate for bone tissue engineering applied to regenerative medicine.

Nanobody: A Small Antibody with Big Implications for Tumor Therapeutic Strategy.

The development of monoclonal antibody treatments for successful tumor-targeted therapies took several decades. However, the efficacy of antibody-based therapy is still confined and desperately needs further improvement. Nanobodies are the recombinant variable domains of heavy-chain-only antibodies, with many unique properties such as small size (~15kDa), excellent solubility, superior stability, ease of manufacture, quick clearance from blood, and deep tissue penetration, which gain increasing acceptance as therapeutical tools and are considered also as building blocks for chimeric antigen receptors as well as for targeted drug delivery. Thus, one of the promising novel developments that may address the deficiency of monoclonal antibody-based therapies is the utilization of nanobodies. This article provides readers the significant factors that the structural and biochemical properties of nanobodies and the research progress on nanobodies in the fields of tumor treatment, as well as their application prospect.

Single-Domain Antibody-Based TCR-Like CAR-T: A Potential Cancer Therapy.

Retargeting the antigen-binding specificity of T cells to intracellular antigens that are degraded and presented on the tumor surface by engineering chimeric antigen receptor (CAR), also named TCR-like antibody CAR-T, remains limited. With the exception of the commercialized CD19 CAR-T for hematological malignancies and other CAR-T therapies aiming mostly at extracellular antigens achieving great success, the rareness and scarcity of TCR-like CAR-T therapies might be due to their current status and limitations. This review provides the probable optimized initiatives for improving TCR-like CAR-T reprogramming and discusses single-domain antibodies administered as an alternative to conventional scFvs and secreted by CAR-T cells, which might be of great value to the development of CAR-T immunotherapies for intracellular antigens.