BiFACIAL (Biomimetic Freestanding Anisotropic Catechol-Interfaces with Asymmetrically Layered) Films as Versatile Extracellular Matrix Substitutes

Zhang

ACS Appl. Mater. Interfaces

et al. 2021

Hydrogel strain sensors have attracted tremendous attention in medical monitoring, flexible wearable devices, and human–machine interfaces. However, traditional hydrogels exhibit isotropic sensing performance based on their isotropic structure. Therefore, it is challenging to fabricate a hydrogel with an anisotropic structure similar to human tissues for achieving anisotropic sensing characteristics. Herein, we proposed a simple and effective method for preparing anisotropic poly(vinyl alcohol) (PVA) conductive hydrogels, which demonstrated anisotropic mechanical properties and anisotropic ion conductivity. The anisotropic hydrogel was successfully constructed through first thermal stretching and then directional freezing. The mechanical strength of hydrogels along the parallel stretching direction (stress of 1596 kPa and toughness of 3.69 MJ/m3) was higher than that of the hydrogels along the vertical stretching direction (stress of 883.1 kPa and toughness of 1.96 MJ/m3). Moreover, the hydrogel showed anisotropic conductivity on the advantage of the different ion channels. The prepared hydrogel sensor exhibited anisotropic sensing for multidirectional stress in the strain range from 0.5 to 100%. The gauge factors (GF) parallel to the stretching direction were greater than the GF vertical to the stretching direction. The anisotropic hydrogel sensors are expected to have broad application prospects in flexible wearable devices and medical monitoring.

Section: Introductionmentioning

confidence: 99%

Muscle-Inspired Anisotropic Hydrogel Strain Sensors

Zhang

ACS Appl. Mater. Interfaces

et al. 2021

Front. Bioeng. Biotechnol.

“…However, even with the final and complete device, questions may arise, for example, in relation with the side exposed to the cells during the assay. Indeed, the controlled construction of bifacial biomaterials is a strategy to mimic anisotropic elements of the organism, such as skin layers or blood vessels (Im et al, 2018). The difference of properties as a function of the part of the sample can also be caused by the production process of biomaterials (Lucarelli et al, 2010).…”

Section: Sample Selectionmentioning

confidence: 99%

Preclinical in vitro evaluation of implantable materials: conventional approaches, new models and future directions

Frisch,

Clavier,

Belhamdi

et al. 2023

Nowadays, implants and prostheses are widely used to repair damaged tissues or to treat different diseases, but their use is associated with the risk of infection, inflammation and finally rejection. To address these issues, new antimicrobial and anti-inflammatory materials are being developed. Aforementioned materials require their thorough preclinical testing before clinical applications can be envisaged. Although many researchers are currently working on new in vitro tissues for drug screening and tissue replacement, in vitro models for evaluation of new biomaterials are just emerging and are extremely rare. In this context, there is an increased need for advanced in vitro models, which would best recapitulate the in vivo environment, limiting animal experimentation and adapted to the multitude of these materials. Here, we overview currently available preclinical methods and models for biological in vitro evaluation of new biomaterials. We describe several biological tests used in biocompatibility assessment, which is a primordial step in new material’s development, and discuss existing challenges in this field. In the second part, the emphasis is made on the development of new 3D models and approaches for preclinical evaluation of biomaterials. The third part focuses on the main parameters to consider to achieve the optimal conditions for evaluating biocompatibility; we also overview differences in regulations across different geographical regions and regulatory systems. Finally, we discuss future directions for the development of innovative biomaterial-related assays: in silico models, dynamic testing models, complex multicellular and multiple organ systems, as well as patient-specific personalized testing approaches.

“…Targeted selection, high adsorption capacity, and fast delivery for objective peptides have been the key aspects of such materials. In this connection, porous structure − with unique surface properties , and well-designed nanomorphology − are critical factors to award target-oriented properties to these materials.…”

Section: Introductionmentioning

confidence: 99%

Nitrogen-Doped Hollow Copolymer Tube via Template-Free Asynchronous Polymerization with Highly Selective Separation of Hydrophilic Dipeptide for Enhancing Inhibitory Activity of Angiotensin Converting Enzyme

Chang

ACS Appl. Mater. Interfaces

et al. 2019

A N-doped hollow copolymer tube (NHCT) was fabricated via template-free one-pot asynchronous polymerization strategy. Discrepancies of monomer polymerization speed and their hydrophilic–hydrophobic interaction resulted in the assembly of a hollow tube having inner diameter and double wall thickness of ∼230 and 40 nm, respectively. The formation and growth mechanism of NHCT analyzed via advanced characterization revealed that the unique growth processes tuned a demarcating surface layer between inner (hydrophilic) and outer (hydrophobic) layers. The screening and recognition ability of NHCT were determined for two specific dipeptides (WW and RR) possessing great discrepancies in hydrophilicity and angiotensin converting enzyme inhibitory (ACE-I) activity. NHCT realized high adsorption capacity (1.57 mmol/g) and selectivity (∼1274) for hydrophilic dipeptide RR (low ACE-I activity) from the mixture of RR/WW. As a result, ACE-I activity for residual solution were enhanced about 4.1 times as compared to original solution from natural silkworm pupae protein hydrolysate. Awarding to these results and its facile and discerning ability, NHCT can be envisioned to be of great value for the separation of small functional peptides from a natural edible source.