Targeting resistant breast cancer stem cells in a three-dimensional culture model with oleuropein encapsulated in methacrylated alginate microparticles.

BACKGROUND: Cancer stem cells (CSCs) are a subpopulation of cancer cells that are believed to be responsible for tumor initiation, progression, metastasis, and resistance to conventional therapies. Oleuropein as a natural compound found in olive leaves and olive oil, has potential therapeutic effects in cancer treatment, particularly in targeting CSCs. It induces apoptosis in CSCs while sparing normal cells, inhibit proliferation, migration, and invasion, and suppress the self-renewal ability of CSCs. Additionally, oleuropein has shown synergistic effects with conventional chemotherapy drugs, enhancing their efficacy against CSCs. OBJECTIVES: This study aims to selectively target therapeutically resistant cancer stem cells (CSCs) within a heterogeneous tumor population by utilizing oleuropein (OLE) encapsulated in methacrylated alginate (OLE-mALG) within an in vivo-like microenvironment. PURPOSE: This study aims to target therapeutically resistant cancer stem cells (CSCs) with oleuropein (OLE) encapsulated in the methacrylated alginate (OLE-mALG) in a heterogeneous tumor population with an in vivo-like microenvironment. METHODS: Co-culture of CSCs with non-tumorogenic MCF-12 A cells was performed, the 3D breast cancer model was supported with methocel/matrigel/collagen-I, and vascularization was ensured with human umbilical vein endothelial cells (HUVEC). Then, OLE-loaded methacrylated alginate microparticles (mALG) were formed by dual crosslinking in the presence of both ionic and visible light obtained with a droplet based microfluidic system. The characterization and effectiveness of the produced OLE-mALG were evaluated by the FTIR, swelling/degradation/release analysis. Before producing OLE loaded mALG microparticles, a preliminary study was carried out to determine the effective dose of OLE for cells and the duration of OLE action on MCF-7, CSCs and MCF-12 A. Subsequently, CSC viability (WST-1), apoptosis (Bcl-2, Bax, caspase-3, caspase-9), stemness (OCT3/4, NANOG, SOX2), EMT profile (E-cadherin, Vimentin, Slug) and proliferation (SURVIVIN, p21, CYCLIN D1) after OLE-mALG treatment were all evaluated in the 3D model. RESULTS: OLE was encapsulated in mALG with an efficiency of 90.49% and released 73% within 7 h. OLE-mALG induced apoptosis through the decrease in anti-apoptotic Bcl-2 and an increase in pro-apoptotic Bax, caspase-3, and caspase-9 protein levels. While Vimentin and Slug protein levels decreased after 200 µg/mL OLE-mALG treatment to 3D breast cancer culture, E-cadherin levels increased. OLE-mALG treatment to CSC co-culture led to a decrease in proliferation by triggering p21/SURVIVIN expressions, and also resulted in an increase in stemness genes (OCT3/4/NANOG/SOX2). CONCLUSION: 200 µg/mL OLE-loaded mALG microparticles suppressed epithelial-to-mesenchymal transition by suppressing Vimentin and Slug protein levels, and increased E-cadherin levels in the 3D breast cancer model we created with CSCs, MCF-12 A and HUVECs. This complex system may allow the use of personalized cells for rapid drug screening in preclinical studies compared to animal experiments. OLE-mALG showed apoptotic and metastasis suppressive properties in cancer cells and it was concluded that it can be used in combination with or alternatively with chemotherapeutic agents to target breast cancer stem cells.

Optimization of methacrylated gelatin /layered double hydroxides nanocomposite cell-laden hydrogel bioinks with high printability for 3D extrusion bioprinting.

Layered double hydroxides (LDHs) offer unique source of inspiration for design of bone mimetic biomaterials due to their superior mechanical properties, drug delivery capability and regulation cellular behaviors, particularly by divalent metal cations in their structure. Three-dimensional (3D) bioprinting of LDHs holds great promise as a novel strategy thanks to highly tunable physiochemical properties and shear-thinning ability of LDHs, which allow shape fidelity after deposition. Herein, we introduce a straightforward strategy for extrusion bioprinting of cell laden nanocomposite hydrogel bioink of gelatin methacryloyl (GelMA) biopolymer and LDHs nanoparticles. First, we synthesized LDHs by co-precipitation process and systematically examined the effect of LDHs addition on printing parameters such as printing pressure, extrusion rate, printing speed, and finally bioink printability in creating grid-like constructs. The developed hydrogel bioinks provided precise control over extrudability, extrusion uniformity, and structural integrity after deposition. Based on the printability and rheological analysis, the printability could be altered by controlling the concentration of LDHs, and printability was found to be ideal with the addition of 3 wt % LDHs. The addition of LDHs resulted in remarkably enhanced compressive strength from 652 kPa (G-LDH0) to 1168 kPa (G-LDH3). It was shown that the printed nanocomposite hydrogel scaffolds were able to support encapsulated osteoblast survival, spreading, and proliferation in the absence of any osteoinductive factors taking advantage of LDHs. In addition, cells encapsulated in G-LDH3 had a larger cell spreading area and higher cell aspect ratio than those encapsulated in G-LDH0. Altogether, the results demonstrated that the developed GelMA/LDHs nanocomposite hydrogel bioink revealed a high potential for extrusion bioprinting with high structural fidelity to fabricate implantable 3D hydrogel constructs for repair of bone defects.

Photocurable silk fibroin-based tissue sealants with enhanced adhesive properties for the treatment of corneal perforations.

Corneal defects are associated with corneal tissue engineering in terms of vision loss. The treatment of corneal defects is an important clinical challenge due to a uniform corneal thickness and the apparent lack of regenerative ability. In this work, we synthesized a biocompatible and photocrosslinkable ocular tissue adhesive composite hydrogel prepared by using methacrylated gelatin (GelMA), which is called the most favorable derivative of gelatin used as a tissue adhesive, silk fibroin (SF), and GelMA/SF (GS) with high adhesion behaviours for use in corneal injuries. The adhesion behaviours of the materials prepared in the presence of silk fibroin were improved. Importantly, the effect of different UV curing times on the adhesion properties of the prepared materials was also investigated. The prepared GS tissue adhesives showed high physiological adhesion. GS can be modulated to increase its adhesive strength up to 3 times compared to G. GS was also found to be biocompatible and have a high healing potential. In addition, the obtained transmission value of GS is also close to that of the human cornea. GS supported cellular adhesion and proliferation. The burst pressure strength for fresh cornea of the GS-60s sealants (144.5 ± 13 kPa) was determined to be higher than that of the G-60s sealants (52.6 ± 33.5 kPa).

Selection of natural biomaterials for micro-tissue and organ-on-chip models.

The desired organ in micro-tissue models of organ-on-a-chip (OoC) devices dictates the optimum biomaterials, divided into natural and synthetic biomaterials. They can resemble biological tissues' biological functions and architectures by constructing bioactivity of macromolecules, cells, nanoparticles, and other biological agents. The inclusion of such components in OoCs allows them having biological processes, such as basic biorecognition, enzymatic cleavage, and regulated drug release. In this report, we review natural-based biomaterials that are used in OoCs and their main characteristics. We address the preparation, modification, and characterization methods of natural-based biomaterials and summarize recent reports on their applications in the design and fabrication of micro-tissue models. This article will help bioengineers select the proper biomaterials based on developing new technologies to meet clinical expectations and improve patient outcomes fusing disease modeling.

Modeling of Artificial 3D Human Placenta.

The placenta is the main organ that allows the fertilized oocyte to develop and mature. It allows the fetus to grow in the prenatal period by transferring oxygen and nutrients between the mother and the fetus. It acts as a basic endocrine organ which creates the physiological changes related to pregnancy and birth in the mother. Removal of wastes and carbon dioxide from the fetus is also achieved by the placenta. It prevents the rejection of the fetus and protects the fetus from harmful effects. Research on the human placenta focuses on understanding the placental structure and function to illuminate the complex structure of this important organ with technological advances. The structure and function of the placental barrier have been investigated with in vitro studies in 2D/3D, and various results have been published comparatively. In this review, we introduce the nature of the placenta with its 3D composition which has been called niche. Different cell types and placental structures are presented. We describe the systems and approaches used in the creation of current 3D placenta, placental transfer models as 3D placental barriers, and micro-engineered 3D placenta on-a-chip to explore complicated placental responses to nanoparticle exposure.

Highlights on Advancing Frontiers in Tissue Engineering.

The field of tissue engineering continues to advance, sometimes in exponential leaps forward, but also sometimes at a rate that does not fulfill the promise that the field imagined a few decades ago. This review is in part a catalog of success in an effort to inform the process of innovation. Tissue engineering has recruited new technologies and developed new methods for engineering tissue constructs that can be used to mitigate or model disease states for study. Key to this antecedent statement is that the scientific effort must be anchored in the needs of a disease state and be working toward a functional product in regenerative medicine. It is this focus on the wildly important ideas coupled with partnered research efforts within both academia and industry that have shown most translational potential. The field continues to thrive and among the most important recent developments are the use of three-dimensional bioprinting, organ-on-a-chip, and induced pluripotent stem cell technologies that warrant special attention. Developments in the aforementioned areas as well as future directions are highlighted in this article. Although several early efforts have not come to fruition, there are good examples of commercial profitability that merit continued investment in tissue engineering. Impact statement Tissue engineering led to the development of new methods for regenerative medicine and disease models. Among the most important recent developments in tissue engineering are the use of three-dimensional bioprinting, organ-on-a-chip, and induced pluripotent stem cell technologies. These technologies and an understanding of them will have impact on the success of tissue engineering and its translation to regenerative medicine. Continued investment in tissue engineering will yield products and therapeutics, with both commercial importance and simultaneous disease mitigation.

Use of electroconductive biomaterials for engineering tissues by 3D printing and 3D bioprinting.

Existing methods of engineering alternatives to restore or replace damaged or lost tissues are not satisfactory due to the lack of suitable constructs that can fit precisely, function properly and integrate into host tissues. Recently, three-dimensional (3D) bioprinting approaches have been developed to enable the fabrication of pre-programmed synthetic tissue constructs that have precise geometries and controlled cellular composition and spatial distribution. New bioinks with electroconductive properties have the potential to influence cellular fates and function for directed healing of different tissue types including bone, heart and nervous tissue with the possibility of improved outcomes. In the present paper, we review the use of electroconductive biomaterials for the engineering of tissues via 3D printing and 3D bioprinting. Despite significant advances, there remain challenges to effective tissue replacement and we address these challenges and describe new approaches to advanced tissue engineering.

Multimaterial bioprinting and combination of processing techniques towards the fabrication of biomimetic tissues and organs.

Tissue reconstruction requires the utilization of multiple biomaterials and cell types to replicate the delicate and complex structure of native tissues. Various three-dimensional (3D) bioprinting techniques have been developed to fabricate customized tissue structures; however, there are still significant challenges, such as vascularization, mechanical stability of printed constructs, and fabrication of gradient structures to be addressed for the creation of biomimetic and complex tissue constructs. One approach to address these challenges is to develop multimaterial 3D bioprinting techniques that can integrate various types of biomaterials and bioprinting capabilities towards the fabrication of more complex structures. Notable examples include multi-nozzle, coaxial, and microfluidics-assisted multimaterial 3D bioprinting techniques. More advanced multimaterial 3D printing techniques are emerging, and new areas in this niche technology are rapidly evolving. In this review, we briefly introduce the basics of individual 3D bioprinting techniques and then discuss the multimaterial 3D printing techniques that can be developed based on combination of these techniques for the engineering of complex and biomimetic tissue constructs. We also discuss the perspectives and future directions to develop state-of-the-art multimaterial 3D bioprinting techniques for engineering tissues and organs.

Role of biomaterials in the diagnosis, prevention, treatment, and study of corona virus disease 2019 (COVID-19).

Recently emerged novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the resulting corona virus disease 2019 (COVID-19) led to urgent search for methods to prevent and treat COVID-19. Among important disciplines that were mobilized is the biomaterials science and engineering. Biomaterials offer a range of possibilities to develop disease models, protective, diagnostic, therapeutic, monitoring measures, and vaccines. Among the most important contributions made so far from this field are tissue engineering, organoids, and organ-on-a-chip systems, which have been the important frontiers in developing tissue models for viral infection studies. Also, due to low bioavailability and limited circulation time of conventional antiviral drugs, controlled and targeted drug delivery could be applied alternatively. Fortunately, at the time of writing this paper, we have two successful vaccines and new at-home detection platforms. In this paper, we aim to review recent advances of biomaterial-based platforms for protection, diagnosis, vaccination, therapeutics, and monitoring of SARS-CoV-2 and discuss challenges and possible future research directions in this field.

Microphysiological Systems: Next Generation Systems for Assessing Toxicity and Therapeutic Effects of Nanomaterials.

Microphysiological systems, also known as organ-on-a-chip platforms, show promise for the development of new testing methods that can be more accurate than both conventional two-dimensional cultures and costly animal studies. The development of more intricate microphysiological systems can help to better mimic the human physiology and highlight the systemic effects of different drugs and materials. Nanomaterials are among a technologically important class of materials used for diagnostic, therapeutic, and monitoring purposes; all of which and can be tested using new organ-on-a-chip systems. In addition, the toxicity of nanomaterials which have entered the body from ambient air or diet can have deleterious effects on various body systems. This in turn can be studied in newly developed microphysiological systems. While organ-on-a-chip models can be useful, they cannot pick up secondary and systemic toxicity. Thus, the utilization of multi-organ-on-a-chip systems for advancing nanotechnology will largely be reflected in the future of drug development, toxicology studies and precision medicine. Various aspects of related studies, current challenges, and future perspectives are discussed in this paper.

Engineering Tough, Injectable, Naturally Derived, Bioadhesive Composite Hydrogels.

Engineering mechanically robust bioadhesive hydrogels that can withstand large strains may open new opportunities for the sutureless sealing of highly stretchable tissues. While typical chemical modifications of hydrogels, such as increasing the functional group density of crosslinkable moieties and blending them with other polymers or nanomaterials have resulted in improved mechanical stiffness, the modified hydrogels have often exhibited increased brittleness resulting in deteriorated sealing capabilities under large strains. Furthermore, highly elastic hydrogels, such as tropoelastin derivatives are highly expensive. Here, gelatin methacryloyl (GelMA) is hybridized with methacrylate-modified alginate (AlgMA) to enable ion-induced reversible crosslinking that can dissipate energy under strain. The hybrid hydrogels provide a photocrosslinkable, injectable, and bioadhesive platform with an excellent toughness that can be tailored using divalent cations, such as calcium. This class of hybrid biopolymers with more than 600% improved toughness compared to GelMA may set the stage for durable, mechanically resilient, and cost-effective tissue sealants. This strategy to increase the toughness of hydrogels may be extended to other crosslinkable polymers with similarly reactive moieties.

Evaluation and comparison of Ga-68 DOTA-TATE and Ga-68 DOTA-NOC PET/CT imaging in well-differentiated thyroid cancer.

BACKGROUND: Somatostatin receptor (Sstr) scintigraphy with radiolabelled somatostatin analogues has been used extensively for the diagnosis and therapy of Sstr-expressing tumours. It has been shown that well-differentiated thyroid cancer (WDTC) cells have a high expression of Sstr2, Sstr3 and Sstr5. Hence, WDTC cells could be an ideal target for the evaluation of lesion uptake of Ga-68 DOTA-1-NaI3-octreotide (DOTA-NOC), which has a high affinity not only to Sstr2 but also to Sstr3 and Sstr5. The aim of the present study was to evaluate the value of Ga-68 DOTA-NOC as a target for Sstr2-expressing, Sstr3-expressing and Sstr5-expressing tumours in WDTC patients and to compare the results with those of Ga-68 DOTA-TATE in the same patient population. METHOD: Thirteen patients with WDTC were included in our study: nine with papillary thyroid cancer, three with Hurthle cell carcinoma and one with follicular thyroid carcinoma. All patients had elevated serum thyroglobulin levels and negative post-therapeutic I-131 whole-body scans, which were obtained after the last radioiodine treatment. All patients had undergone two consecutive PET imaging studies with Ga-68 DOTA-D-Phe1-Tyr3-octreotate (DOTA-TATE) and Ga-68 DOTA-NOC, respectively. All images were evaluated visually, and maximum standardized uptake values were calculated. RESULTS: Both Ga-68 DOTA-TATE and Ga-68 DOTA-NOC PET images gave comparable results. Among the 13 patients, imaging with both Ga-68 DOTA-TATE and Ga-68 DOTA-NOC gave negative results in five (38%) patients and positive results in eight (62%) patients. A total of 45 lesions were identified on Ga-68 DOTA-TATE images and 42 on Ga-68 DOTA-NOC images; three lesions were missed. Lesion uptake was significantly higher on Ga-68 DOTA-TATE images. Maximum standardized uptake values of Ga-68 DOTA-TATE and Ga-68 DOTA-NOC were 12.9±9.1 and 6.3±4.1 (n=54, P<0.001), respectively. CONCLUSION: Our study suggested that Ga-68 DOTA-TATE has a higher lesion uptake even in WDTC patients and may have potential advantage over Ga-68 DOTA-NOC.