PLLA-gelatin composite fiber membranes incorporated with functionalized CeNPs as a sustainable wound dressing substitute promoting skin regeneration and scar remodelling

The need of wound dressing material that can accelerate wound healing is increasing and will last a long time. In this study, Cerium Oxide Nanoparticles (CeNPs) incorporated poly-L-lactic acid (PLLA)-gelatin...

Materials for Orthopedic Bioimplants: Modulating Degradation and Surface Modification Using Integrated Nanomaterials

Significant research and development in the field of biomedical implants has evoked the scope to treat a broad range of orthopedic ailments that include fracture fixation, total bone replacement, joint arthrodesis, dental screws, and others. Importantly, the success of a bioimplant depends not only upon its bulk properties, but also on its surface properties that influence its interaction with the host tissue. Various approaches of surface modification such as coating of nanomaterial have been employed to enhance antibacterial activities of a bioimplant. The modified surface facilitates directed modulation of the host cellular behavior and grafting of cell-binding peptides, extracellular matrix (ECM) proteins, and growth factors to further improve host acceptance of a bioimplant. These strategies showed promising results in orthopedics, e.g., improved bone repair and regeneration. However, the choice of materials, especially considering their degradation behavior and surface properties, plays a key role in long-term reliability and performance of bioimplants. Metallic biomaterials have evolved largely in terms of their bulk and surface properties including nano-structuring with nanomaterials to meet the requirements of new generation orthopedic bioimplants. In this review, we have discussed metals and metal alloys commonly used for manufacturing different orthopedic bioimplants and the biotic as well as abiotic factors affecting the failure and degradation of those bioimplants. The review also highlights the currently available nanomaterial-based surface modification technologies to augment the function and performance of these metallic bioimplants in a clinical setting.

Preparation and characterization of layer-by-layer hypoglycemic nanoparticles with pH-sensitivity for oral insulin delivery

We developed an insulin oral delivery system with the combination of pH-sensitive material and structure to avoid intestinal degradation.

Fabrication and characterization of three-dimensional poly(lactic acid-co-glycolic acid), atelocollagen, and fibrin bioscaffold composite for intervertebral disk tissue engineering application

The use of synthetically derived poly(lactic- co-glycolic acid) scaffold and naturally derived materials in regeneration of intervertebral disks has been reported in many previous studies. However, the potential effect of poly(lactic- co-glycolic acid) in combination with atelocollagen or fibrin or both atelocollagen and fibrin bioscaffold composite have not been mentioned so far. This study aims to fabricate and characterize three-dimensional poly(lactic- co-glycolic acid) scaffold incorporated with (1) atelocollagen, (2) fibrin, and (3) both atelocollagen and fibrin combination for intervertebral disk tissue engineering application. The poly(lactic- co-glycolic acid) without any natural, bioscaffold composites was used as control. The chemical conformation, morphology, cell–scaffold attachment, porosity, water uptake capacity, thermal properties, mechanical strength, and pH level were evaluated on all scaffolds using attenuated total reflectance Fourier transform infrared, scanning electron microscope, gravimetric analysis, swelling test, differential scanning calorimetry, and Instron E3000, respectively. Biocompatibility test was conducted to assess the intervertebral disk, annulus fibrosus cells viability using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The attenuated total reflectance Fourier transform infrared results demonstrated notable peaks of amide bond suggesting interaction of atelocollagen, fibrin, and both atelocollagen and fibrin combination into the poly(lactic- co-glycolic acid) scaffold. Based on the scanning electron microscope observation, the pore size of the poly(lactic- co-glycolic acid) structure significantly reduced when it was incorporated with atelocollagen and fibrin. The poly(lactic- co-glycolic acid)–atelocollagen scaffolds demonstrated higher significant swelling ratios, mechanical strength, and thermal stability than the poly(lactic- co-glycolic acid) scaffold alone. All the three bioscaffold composite groups exhibited the ability to reduce the acidic poly(lactic- co-glycolic acid) by-product. In this study, the biocompatibility assessment using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide cells proliferation assay demonstrated a significantly higher annulus fibrosus cells viability in poly(lactic- co-glycolic acid)–atelocollagen–fibrin compared to poly(lactic- co-glycolic acid) alone. The cellular attachment is comparable in poly(lactic- co-glycolic acid)–atelocollagen–fibrin and poly(lactic- co-glycolic acid)–fibrin scaffolds. Overall, these results may suggest potential use of poly(lactic- co-glycolic acid) combined with atelocollagen and fibrin bioscaffold composite for intervertebral disk regeneration.

In-Situ-Generated Vasoactive Intestinal Peptide Loaded Microspheres in Mussel-Inspired Polycaprolactone Nanosheets Creating Spatiotemporal Releasing Microenvironment to Promote Wound Healing and Angiogenesis

Vasoactive intestinal peptide (VIP) was reported to promote angiogenesis. Electrospun nanofibers lead to idea wound dressing substrates. Here we report a convenient and novel method to produce VIP loaded microspheres in polycaprolactone (PCL) nanofibrous membrane without complicated processes. We first coated mussel-inspired dopamine (DA) to nanofibers, then used strong adhesive DA to absorb the functional peptide. PCL membrane was then immersed into acetone to generate microspheres with VIP loading. We employed high pressure liquid chromatography to record encapsulation efficiency of (31.8 ± 2.2)% and loading capacity of (1.71 ± 0.16)%. The release profile of VIP from nanosheets showed a prolonged release. The results of laser scanning confocal microscope, scanning electron microscope and cell counting kit-8 proliferation assays showed that cell adhesion and proliferation were promoted. In order to verify the efficacy on wound healing, in vivo implantation was applied in the full-thickness defect wounds of BALB/c mice. Results showed that the wound healing was significantly promoted via favoring the growth of granulation tissue and angiogenesis. However, we found wound re-epithelialization was not significantly improved. The resulting VIP-DA-coated PCL (PCL-DA-VIP) nanosheets with spatiotemporal delivery of VIP could be a potential application in wound treatment and vascular tissue engineering.

Effect of high molecular weight hyaluronic acid on chondrocytes cultured in collagen/hyaluronic acid porous scaffolds

The effects of high molecular weight hyaluronic acid (HA) in porous scaffolds on chondrocytes were studied by using homogeneous collagen/HA scaffolds with controlled pore structure.

Biodegradable uniform microspheres based on solid-in-oil-in-water emulsion for drug delivery: A comparison of homogenization and fluidic device

Based on solid-in-oil-in-water emulsification, we fabricated biodegradable poly(ϵ-caprolactone) microspheres containing gentamicin using conventional homogenization and a fluidic device. The feasibility of the poly(ϵ-caprolactone) microspheres as drug carriers was evaluated in terms of encapsulation efficiency, release behavior of gentamicin, and antimicrobial activity. The poly(ϵ-caprolactone) microspheres prepared using a fluidic device (fluidic device microspheres) had a uniform diameter and a smooth surface, whereas the poly(ϵ-caprolactone) microspheres prepared using conventional homogenization (conventional homogenization microspheres) exhibited polydisperse and a porous structure. At 0.3 wt% of gentamicin concentration, the encapsulation efficiencies of the conventional homogenization and fluidic device microspheres were 39.5% and 72.0%, respectively. In addition, a significant amount of gentamicin was only released initially from the conventional homogenization microspheres, whereas the fluidic device microspheres released gentamicin in a sustained manner for 28 days. These results confirmed the superior performances of the uniform fluidic device microspheres for drug delivery system. We further proposed a model for microsphere formation to explain the difference in performance of the conventional homogenization and fluidic device microspheres.

Collagen microgel-assisted dexamethasone release from PLLA-collagen hybrid scaffolds of controlled pore structure for osteogenic differentiation of mesenchymal stem cells

Directed stem cell differentiation over three-dimensional porous scaffolds capable of releasing bioactive instructive cues is an important tool in tissue engineering. In this research, we have prepared dexamethasone (Dex)-releasing collagen microbead-functionalized poly(L-Lactide)-collagen hybrid scaffolds as an osteoinductive platform for human bone marrow-derived mesenchymal stem cells (MSCs). The scaffolds were prepared by a combined method of emulsion freeze-drying and porogen-leaching using pre-prepared ice collagen particulates as a porogen material. Dex release from the hybrid scaffolds was studied at 37 °C under shaking condition and the impact of released Dex towards osteogenic lineage differentiation was investigated by 3 week in vitro culture of MSCs. The results showed that hybrid scaffolds had controlled pore structure and interconnected pores deposited with collagen fibers. The hybrid scaffold facilitated cell seeding and the spatial localization of Dex/collagen microbeads facilitated a microgel-assisted spatio-temporal control of Dex release. The released Dex was useful for osteogenic differentiation of MSCs, which was confirmed from the elevated expression of osteogenic-specific gene-encoded proteins. The hybrid scaffolds should be useful for regeneration of a functional bone tissue.