The tumor extracellular matrix (ECM) plays a vital role in tumor progression and drug resistance. Previous studies have shown that breast tissue-derived matrices could be an important biomaterial to recreate the complexity of the tumor ECM. We have developed a method for decellularizing and delipidating a porcine breast tissue (TDM) compatible with hydrogel formation. The addition of gelatin methacrylamide and alginate allows this TDM to be bioprinted by itself with good printability, shape fidelity, and cytocompatibility. Furthermore, this bioink has been tuned to more closely recreate the breast tumor by incorporating collagen type I (Col1). Breast cancer cells (BCCs) proliferate in both TDM bioinks forming cell clusters and spheroids. The addition of Col1 improves the printability of the bioink as well as increases BCC proliferation and reduces doxorubicin sensitivity due to a downregulation of HSP90. TDM bioinks also allow a precise three-dimensional printing of scaffolds containing BCCs and stromal cells and could be used to fabricate artificial tumors. Taken together, we have proven that these novel bioinks are good candidates for biofabricating breast cancer models.

Radiopaque tantalum oxide (TaO_x) nanoparticles can be fabricated with a variety of surface chemistries enabling the use of computed tomography to image a vast array of important biolgical phenomena and nanoparticle delivery schemes.

The establishment of tumor microenvironment using biomimetic in vitro models that recapitulate key tumor hallmarks including the tumor supporting extracellular matrix (ECM) is in high demand for accelerating the discovery and preclinical validation of more effective anticancer therapeutics. To date, ECM‐mimetic hydrogels have been widely explored for 3D in vitro disease modeling owing to their bioactive properties that can be further adapted to the biochemical and biophysical properties of native tumors. Gathering on this momentum, herein the current landscape of intrinsically bioactive protein and peptide hydrogels that have been employed for 3D tumor modeling are discussed. Initially, the importance of recreating such microenvironment and the main considerations for generating ECM‐mimetic 3D hydrogel in vitro tumor models are showcased. A comprehensive discussion focusing protein, peptide, or hybrid ECM‐mimetic platforms employed for modeling cancer cells/stroma cross‐talk and for the preclinical evaluation of candidate anticancer therapies is also provided. Further development of tumor‐tunable, proteinaceous or peptide 3D microtesting platforms with microenvironment‐specific biophysical and biomolecular cues will contribute to better mimic the in vivo scenario, and improve the predictability of preclinical screening of generalized or personalized therapeutics.

The alteration of retinoids levels in the skin can cause different disorders in the maturation of epithelial skin cells. Topical administration of these lipophilic molecules is a challenge that can be addressed by encapsulation into drug delivery systems. In this study, retinyl palmitate transferosomes formulated in cream were developed and the increases in the penetration of the active ingredients as well as the biodistribution were evaluated in vitro and in vivo. Transfersomes demonstrated a significant increase in the administration of retinyl palmitate to the epidermis by quantification of the active ingredients in the different layers of the skin, as well as by fluorescence microscopy of biopsies of non-dermatomized pig-ear skin. These results suggest that transfersomes may be an efficient vehicle for the delivery of retinoids to inner layers of the skin, such as the epidermis.

Temperature-sensitive polymeric micelles were prepared from dextran grafted with poly(N-isopropylacrylamide) (PNIPAAm) or polyethylene glycol methyl ether (PEGMA) via controlled radical polymerization and evaluated as delivery systems of the anticancer drug methotrexate (MTX). Polymer-grafting was carried out after introduction of initiating groups onto the polysaccharide backbone, without the need for protection of hydroxyl groups and avoiding the use of toxic solvents. Temperature-responsive dextran-based copolymers were designed to exhibit self-aggregation behaviour, affinity for MTX and high cellular internalization. In addition, some grafted polymers incorporated 2-aminoethyl methacrylate to reinforce MTX encapsulation in the micelles by means of ionic interactions. Dextran-based micelles were cytocompatible and had an appropriate size to be used as drug carriers. MTX release was dependent on the pH and temperature. The combination of poly(2-aminoethylmethacrylate) and PNIPAAm with the dextran backbone permitted the complete release of MTX at normal physiological temperature. Co-polymer micelles were highly internalized by tumour cells (CHO-K1) and, when loaded with MTX, led to enhanced cytotoxicity compared to the free drug.