Development and characterization of Polycaprolactone/chitosan-based scaffolds for tissue engineering of various organs: A review.

Research in creating 3D structures mirroring the extracellular matrix (ECM) with accurate environmental cues holds paramount significance in biological applications.Biomaterials that replicate ECM properties-mechanical, physicochemical, and biological-emerge as pivotal tools in mimicking ECM behavior.Incorporating synthetic and natural biomaterials is widely used to produce scaffolds suitable for the intended organs.Polycaprolactone (PCL), a synthetic biomaterial, boasts commendable mechanical properties, albeit with relatively modest biological attributes due to its hydrophobic nature.Chitosan (CTS) exhibits strong biological traits but lacks mechanical resilience for complex tissue regeneration.Notably, both PCL and CTS have demonstrated their application in tissue engineering for diverse types of tissues.Their combination across varying PCL:CTS ratios has increased the likelihood of fabricating scaffolds to address defects in sturdy and pliable tissues.This comprehensive analysis aspires to accentuate their distinct attributes within tissue engineering across different organs.The central focus resides in the role of PCL:CTS-based scaffolds, elucidating their contribution to the evolution of advanced functional 3D frameworks tailored for tissue engineering across diverse organs.Moreover, this discourse delves into the considerations pertinent to each organ.

Simultaneous usage of sulforaphane nanoemulsion and tannic acid in ternary chitosan/gelatin/PEG hydrogel for knee cartilage tissue engineering: In vitro and in vivo study.

The therapeutic potential of tissue engineering in addressing articular cartilage defects has been a focal point of research for numerous years. Despite its promising outlook, a persistent challenge within this domain is the lack of sufficient functional integration between engineered and natural tissues. This study introduces a novel approach that employs a combination of sulforaphane (SFN) nanoemulsion and tannic acid to enhance cartilage tissue engineering and promote tissue integration in a rat knee cartilage defect model. To substantiate our hypothesis, we conducted a series of in vitro and in vivo experiments. The SFN nanoemulsion was characterized using DLS, zeta potential, and TEM analyses. Subsequently, it was incorporated into a ternary polymer hydrogel composed of chitosan, gelatin, and polyethylene glycol. We evaluated the hydrogel with (H-SFN) and without (H) the SFN nanoemulsion through a comprehensive set of physicochemical, mechanical, and biological analyses. For the in vivo study, nine male Wistar rats were divided into three groups: no implant (Ctrl), H, and H-SFN. After inducing a cartilage defect, the affected area was treated with tannic acid and subsequently implanted with the hydrogels. Four weeks post-implantation, the harvested cartilage underwent histological examination employing H&E, safranin O/fast green, alcian blue, and immunohistochemistry staining techniques. Our results revealed that the SFN nanodroplets had an average diameter of 75 nm and a surface charge of -11.58 mV. Moreover, degradation, swelling rates, hydrophilicity, and elasticity features of the hydrogel incorporating SFN were improved. Histopathological analysis indicated a higher production of GAGs and collagen in the H-SFN group. Furthermore, the H-SFN group exhibited superior cartilage regeneration and tissue integration compared to the Ctrl and H groups. In conclusion, the findings of this study suggest the importance of considering cell protective properties in the fabrication of scaffolds for knee cartilage defects, emphasizing the potential significance of the proposed SFN nanoemulsion and tannic acid approach in advancing the field of cartilage tissue engineering.

In Vitro Release of Glycyrrhiza Glabra Extract by a Gel-Based Microneedle Patch for Psoriasis Treatment.

Microneedle patches are attractive drug delivery systems that give hope for treating skin disorders. In this study, to first fabricate a chitosan-based low-cost microneedle patch (MNP) using a CO2 laser cutter for in vitro purposes was tried and then the delivery and impact of Glycyrrhiza glabra extract (GgE) on the cell population by this microneedle was evaluated. Microscopic analysis, swelling, penetration, degradation, biocompatibility, and drug delivery were carried out to assess the patch's performance. DAPI staining and acridine orange (AO) staining were performed to evaluate cell numbers. Based on the results, the MNs were conical and sharp enough (diameter: 400-500 µm, height: 700-900 µm). They showed notable swelling (2 folds) during 5 min and good degradability during 30 min, which can be considered a burst release. The MNP showed no cytotoxicity against fibroblast cell line L929. It also demonstrated good potential for GgE delivery. The results from AO and DAPI staining approved the reduction in the cell population after GgE delivery. To sum up, the fabricated MNP can be a useful recommendation for lab-scale studies. In addition, a GgE-loaded MNP can be a good remedy for skin disorders in which cell proliferation needs to be controlled.

A review about the role of additives in nerve tissue engineering: growth factors, vitamins, and drugs.

Notably the integration of additives such as growth factors, vitamins, and drugs with scaffolds promoted nerve tissue engineering. This study tried to provide a concise review of all these additives that facilitates nerve regeneration. An attempt was first made to provide information on the main principle of nerve tissue engineering, and then to shed light on the effectiveness of these additives on nerve tissue engineering. Our research has shown that growth factors accelerate cell proliferation and survival, while vitamins play an effective role in cell signalling, differentiation, and tissue growth. They can also act as hormones, antioxidants, and mediators. Drugs also have an excellent and necessary effect on this process by reducing inflammation and immune responses. This review shows that growth factors were more effective than vitamins and drugs in nerve tissue engineering. Nevertheless, vitamins were the most commonly used additive in the production of nerve tissue.

Reliable Kinetics for Drug Delivery with a Microfluidic Device Integrated with the Dialysis Bag.

The clinical success of a drug delivery system turns back to performing experiments with more reliable data. The dialysis bag has been one of the most employed technologies to monitor drug release from nanocarriers, membranes, and scaffolds. Unfortunately, this technology has several challenges regarding the accuracy of the obtained results. In this study, the development of a new system by integrating a microfluidic device and dialysis bag named "MF-dialysis" was carried out to evaluate the accuracy of the reported data. The release study was performed focusing on two drug delivery systems: (i) nanocarrier: Artemisia Absinthium extract-loaded soy protein isolate nanoparticle and (ii) sodium alginate film loaded with the nanocarrier. The obtained nanocarrier was analyzed by SEM, DLS, and zeta potential. The final experimental data were modeled using SigmaPlot software. Based on the results, two distinct but fitted models for the dialysis bag (power model, R2 = 0.99) and MF-dialysis (exponential model, R2 = 0.95) were obtained. MF-dialysis approved that after a while, NPs and films showed more drug release compared to the dialysis bag. To sum up, the MF-dialysis system can be a good candidate for a quick and more reliable study of drug delivery systems.

Tannic Acid as a Green Cross-linker for Biomaterial Applications.

Plant-derived tannic acid as a green material can play an important role in improving the mechanical and physical properties of biomaterials. Tannic acid can be used as an antioxidant, antimicrobial, and cross-linking agent in biomaterial products due to its unique functional groups. Its active phenolic groups can react with biomaterial functional groups to form bonds that improve performance. In this review, the mechanism of effectiveness of tannic acid as a natural crosslinker in improving the properties of biomaterials for various applications, such as tissue engineering, tissue adhesives, drug delivery, wound healing, and toxicity studies, has been investigated. In general, tannic acid can be a suitable alternative to synthetic crosslinkers in biomaterial applications.

Discussing the final size and shape of the reconstructed tissues in tissue engineering.

Tissue engineering (TE) has made a revolution in repairing, replacing, or regenerating tissues or organs, but it has still a long way ahead. The mechanical properties along with suitable physicochemical and biological characteristics are the initial criteria for scaffolds in TE that should be fulfilled. This research will provide another point of view toward TE challenges concerning the morphological and geometrical aspects of the reconstructed tissue and which parameters may affect it. Based on our survey, there is a high possibility that the final reconstructed tissue may be different in size and shape compared to the original design scaffold. Thereby, the 3D-printed scaffold might not guarantee an accurate tissue reconstruction. The main justification for this is the unpredicted behavior of cells, specifically in the outer layer of the scaffold. It can also be a concern when the scaffold is implanted while cell migration cannot be controlled through the in vivo signaling pathways, which might cause cancer challenges. To sum up, it is concluded that more studies are necessary to focus on the size and geometry of the final reconstructed tissue.

Decellularized Alstroemeria flower stem modified with chitosan for tissue engineering purposes: A cellulose/chitosan scaffold.

Utilizing plant-based scaffolds has pulled in the consideration of tissue engineers. Plant tissues own different structures with particular porosity and structure. In this study, the stem of the Alstroemeria flower was designated for decellularization to fabricate a new scaffold. The stems were decellularized and called AFSP and then modified by chitosan and named AFSPC. Osteoblast precursor cell line was employed to assess the biological potential of the final scaffolds. The results uncovered that AFSP owns linear microchannels with a smooth surface. AFSPC delineated uniform chitosan coating on the walls with appropriate roughness. AFSPC showed higher potential in swelling, degradation, diffusion, and having a porous structure than AFSP. Modification with chitosan improved mechanical behavior. Biological assays depicted no cytotoxicity for AFSP and AFSPC. AFSPC showed good cell attachment, proliferation, and migration. In conclusion, modified tissue plants can be a good candidate for tissue engineering of both soft and hard tissues.

Employing hydrogels in tissue engineering approaches to boost conventional cancer-based research and therapies.

Cancer is a complicated disease that involves the efforts of researchers to introduce and investigate novel successful treatments. Traditional cancer therapy approaches, especially chemotherapy, are prone to possible systemic side effects, such as the dysfunction of liver or kidney, neurological side effects and a decrease of bone marrow activity. Hydrogels, along with tissue engineering techniques, provide tremendous potential for scientists to overcome these issues through the release of drugs at the site of tumor. Hydrogels demonstrated competency as potent and stimulus-sensitive drug delivery systems for tumor removal, which is attributed to their unique features, including high water content, biocompatibility, and biodegradability. In addition, hydrogels have gained more attention as 3D models for easier and faster screening of cancer and tumors due to their potential in mimicking the extracellular matrix. Hydrogels as a reservoir can be loaded by an effective dosage of chemotherapeutic agents, and then deliver them to targets. In comparison to conventional procedures, hydrogels considerably decreased the total cost, duration of research, and treatment time. This study provides a general look into the potential role of hydrogels as a powerful tool to augment cancer studies for better analysis of cancerous cell functions, cell survival, angiogenesis, metastasis, and drug screening. Moreover, the upstanding application of drug delivery systems related to the hydrogel in order to sustain the release of desired drugs in the tumor cell-site were explored.

3D printed chitosan/polycaprolactone scaffold for lung tissue engineering: hope to be useful for COVID-19 studies.

To prevent or reduce mortality from lung diseases, new biological materials and scaffolds are needed to conduct more accurate research and support lung tissue regeneration. On the other hand, the outbreak of the COVID-19 virus and its targeting of the human lung has caused many deaths worldwide. The main aim of this study was to provide a biologically and mechanically suitable 3D printed scaffold using chitosan/polycaprolactone bioink for lung tissue engineering. Design-Expert software was employed for studying various compositions for 3D printing. The selected scaffolds underwent physiochemical, biological and mechanical studies to evaluate if they are capable of MRC-5 cell line growth, proliferation, and migration. Based on the results, the average diameter of the chitosan/polycaprolactone strands was measured at 360 µm. Chitosan concentration controlled the printability, while changes in polycaprolactone content did not affect printability. The scaffolds showed excellent potential in swelling, degradation, and mechanical behavior, although they can be modified by adjusting the polycaprolactone content. The scaffolds also revealed notable cell adhesion, nontoxicity, low apoptosis, high proliferation, and cell biocompatibility in vitro. To sum up, scaffold 3 (chitosan/polycaprolactone ratio: 4 : 1) revealed better activity for MRC-5 cell culture. Thereby, this scaffold can be a good candidate for lung tissue engineering and may be applicable for more studies on the COVID-19 virus.

Integration of microbubbles with biomaterials in tissue engineering for pharmaceutical purposes.

Tissue engineering with the aid of biomaterials is a novel and promising knowledge aiming at improving human life expectancy. Besides, microbubbles are increasingly employed in biomedical applications due to their capability as a reservoir of therapeutic agents and oxygen molecules. In the present study, Microbubbles as the backbone of the research are produced as one of the potent devices in tissue engineering approaches, including drug delivery, wound healing, 3D printing, and scaffolding. It was shown that microbubbles are capable of promoting oxygen penetration and boosting the wound healing process by supplying adequate oxygen. Microbubbles also demonstrated their strength and potency in advancing drug delivery systems by reinforcing mass transfer phenomena. Furthermore, microbubbles developed the mechanical and biological characteristics of engineered scaffolds by manipulating the pores. Increasing cell survival, the biological activity of cells, angiogenesis, cell migration, and also nutrient diffusion into the inner layers of the scaffold were other achievements by microbubbles. In conclusion, the interest of biomedical communities in simultaneous usage of microbubbles and biomaterials under tissue engineering approaches experiences remarkable growth in Pharmaceutical studies.

Practical stabilization of time-delay fractional-order systems by parametric controllers.

This paper stabilization of time-delayed fractional-order systems by unlimited controllers is considered. To achieve the best controller so that the system be stable, the parameters of the feedback matrices are determinate with the minimum norm. Various constraints applied by the designer to obtain the desired performance criteria. We use the partial eigenvalue assignment (PEVA) method to decrease the constraints and ranks of matrices. The presented method is implemented in two numerical examples.

Comparison of muscle synergies extracted from both legs during cycling at different mechanical conditions.

Muscle synergies are the building blocks for generating movement by the central nervous system (CNS). According to this hypothesis, CNS decreases the complexity of motor control by combination of a small number of muscle synergies. The aim of this work is to investigate similarity of muscle synergies during cycling across various mechanical conditions. Twenty healthy subjects performed three 6- min cycling tasks at over a range of rotational speed (40, 50, and 60 rpm) and resistant torque (3, 5, and 7 N/m). Surface electromyography (sEMG) signals were recorded during pedaling from eight muscles of the right and left legs. We extracted four synchronous muscle synergies by using the non-negative matrix factorization (NMF) method. Mean and standard deviation of the goodness of the signal reconstruction (R2) for all subjects was obtained 0.9898 ± 0.0535. We investigated the functional roles of both leg muscles during cycling by synchronous muscle synergy extraction. We compared the muscle synergies extracted from all subjects in all mechanical conditions. The total mean and standard deviation of the similarity of synergy vectors for all subjects in all mechanical conditions was obtained 0.8788 ± 0.0709. We found the high degrees of similarity among the sets of synchronous muscle synergies across mechanical conditions and also across different subjects. Our results demonstrated that different subjects at different mechanical conditions use the same motor control strategies for cycling, despite inter-individual variability of muscle patterns.