Tissue-engineering the larynx: Effect of decellularization on human laryngeal framework and the cricoarytenoid joint

Cationic nanoparticles enhance T cell tumor infiltration and antitumor immune responses to a melanoma vaccine

In clinical settings, cancer vaccines as monotherapies have displayed limited success compared to other cancer immunotherapeutic treatments. Nanoscale formulations have the ability to increase the efficacy of cancer vaccines by combatting the immunosuppressive nature of the tumor microenvironment. Here, we have synthesized a previously unexplored cationic polymeric nanoparticle formulation using polyamidoamine dendrimers and poly(d,l-lactic-co-glycolic acid) that demonstrate adjuvant properties in vivo. Tumor-challenged mice vaccinated with an adenovirus-based cancer vaccine [encoding tumor-associated antigen (TAA)] and subsequently treated with this nanoparticulate formulation showed significant increases in TAA-specific T cells in the peripheral blood, reduced tumor burden, protection against tumor rechallenge, and a significant increase in median survival. An investigation into cell-based pathways suggests that administration of the nanoformulation at the site of the developing tumor may have created an inflammatory environment that attracted activated TAA-specific CD8⁺ T cells to the vicinity of the tumor, thus enhancing the efficacy of the vaccine.

Three-dimensional bio-printing of decellularized extracellular matrix-based bio-inks for cartilage regeneration: a systematic review

Cartilage injuries are common problems that increase with the population aging. Cartilage is an avascular tissue with a relatively low level of cellular mitotic activity, which makes it impossible to heal spontaneously. To compensate for this problem, three-dimensional bio-printing has attracted a great deal of attention in cartilage tissue engineering. This emerging technology aims to create three-dimensional functional scaffolds by accurately depositing layer-by-layer bio-inks composed of biomaterial and cells. As a novel bio-ink, a decellularized extracellular matrix can serve as an appropriate substrate that contains all the necessary biological cues for cellular interactions. Here, this review is intended to provide an overview of decellularized extracellular matrix-based bio-inks and their properties, sources, and preparation process. Following this, decellularized extracellular matrix-based bio-inks for cartilage tissue engineering are discussed, emphasizing cell behavior and in-vivo applications. Afterward, the current challenges and future outlook will be discussed to determine the conclusing remarks.

Tissue Engineering the Pinna: Comparison and Characterization of Human Decellularized Auricular Biological Scaffolds

Decellularization is one of the promising techniques in tissue engineering used to create a biological scaffold for subsequent repopulation with the patient's own cells. This study aims to compare two different decellularization protocols to optimize the process of auricle decellularization by assessing and characterizing the decellularization effects on human auricular cartilage. Herein, 12 pairs (8 females, 4 males) of freshly frozen adult human cadaveric auricles were de-epithelialized and defatted leaving only the cartilaginous framework. An auricle from each pair was randomly assigned to either protocol A (latrunculin B-based decellularization) or protocol B (trypsin-based decellularization). Gross examination of the generated scaffolds demonstrated preservation of the auricles' contours and a change in color from pinkish-white to yellowish-white. Hematoxylin and eosin staining demonstrated empty cartilaginous lacunae in both study groups, which confirms the depletion of cells. However, there was greater preservation of the extracellular matrix in auricles decellularized with protocol A as compared to protocol B. Comparing protocol A to protocol B, Masson's trichrome and Safranin-O stains also demonstrated noticeable preservation of collagen and proteoglycans, respectively. Additionally, scanning electron micrographs demonstrated preservation of the cartilaginous microtopography in both study groups. Biomechanical testing demonstrated a substantial decrease in Young's modulus after decellularization using protocol B (1.3 MPa), albeit not significant (P-value > 0.05) when compared to Young's modulus prior to decellularization (2.6 MPa) or after decellularization with protocol A (2.7 MPa). A DNA quantification assay demonstrated a significant drop (P-value < 0.05) in the DNA content after decellularization with protocol A (111.0 ng/mg) and protocol B (127.6 ng/mg) in comparison to before decellularization (865.3 ng/mg). Overall, this study demonstrated effective decellularization of human auricular cartilage, and it is concluded that protocol A provided greater preservation of the extracellular matrix and biomechanical characteristics. These findings warrant proceeding with the assessment of inflammation and cell migration in a decellularized scaffold using an animal model.