Layered double hydroxide-based nanocomposite scaffolds in tissue engineering applications

Layered double hydroxides (LDHs), when incorporated into biomaterials, provide a tunable composition, controllable particle size, anion exchange capacity, pH-sensitive solubility, high-drug loading efficiency, efficient gene and drug delivery, controlled release and effective intracellular uptake, natural biodegradability in an acidic medium, and negligible toxicity. In this review, we study potential applications of LDH-based nanocomposite scaffolds for tissue engineering. We address how LDHs provide new solutions for nanostructure stability and enhance in vivo studies\u27 success

pH sensitive functionalized hyperbranched polyester based nanoparticulate system for the receptor-mediated targeted cancer therapy

The aim of this study is to develop a novel folic acid conjugated, DL-lysine modified, PEGylated, the 3rd generation hyperbranched polymer (HBP-PEG-Lys-FA) for use in receptor-mediated therapy. 5-fluorouracil, model anti-cancer drug, loaded nanoparticles were found an average size of 177 nm with loading efficiency of 23.18%. In vitro drug release studies demonstrated that nanoparticles showed pH-dependent release. HBP-PEG-Lys-FA were efficiently taken up by HeLa cells and specificity of targeted nanoparticles to folate receptors of cells was proved. It was concluded that the HBP-PEG-Lys-FA nanoparticles can provide an advantage on delivering of the drug efficiently into the cytosol for cancer therapy

Design of an amphiphilic hyperbranched core/shell-type polymeric nanocarrier platform for drug delivery

An amphiphilic core/shell-type polymer-based drug carrier system (HPAE- PCL-b-MPEG), composed of hyperbranched poly(aminoester)-based polymer (HPAE) as the core building block and poly(ethylene glycol)-b-poly(epsilon-caprolactone) diblock polymers (MPEG-b-PCL) as the shell building block, was designed. The synthesized polymers were characterized with FTIR, H-1 NMR, C-13 NMR, and GPC analysis. Monodisperse HPAE-PCL-b-MPEG nanoparticles with dimensions of <200 nm and polydispersity index of <0.5 were prepared by nanoprecipitation method and characterized with SEM, particle size, and zeta potential analysis. 5-Fluorouracil was encapsulated within HPAE-PCL-b-MPEG nanoparticles. In vitro drug release profiles and cytotoxicity of blank and 5-fluorouracil-loaded nanoparticles were examined against the human colon cancer HCT116 cell line. All results suggest that HPAE-PCL-b-MPEG nanoparticles offer an alternative and effective drug nanocarrier system for drug delivery applications

Boric acid-impregnated silk fibroin/gelatin/hyaluronic acid-based films for improving the wound healing process

Recently, with the progression in wound dressings, the importance of the biocompatible material with enhanced features for potential applications in the biomedical field has been more developed. Current strategies focus on the acceleration of the wound healing by systematically designed dressing materials. In this study, biocompatible hydrogel films with the combination of silk fibroin, hyaluronic acid and gelatin biopolymers were fabricated. To gain the enhanced wound healing behavior of wound dressings, boric acid (BA) was formulated in various ratios. The prepared hydrogel films were characterized in terms of FTIR, TGA, DSC, and SEM analysis. Following to the swelling and mechanical tests, in vitro biocompatibility and wound healing tests were performed against L929 fibroblast cell line. Results suggest that the presence of 1% (wt/vol) BA in the formulation of silk fibroin/gelatin/hyaluronic acid based hydrogel films is the key in providing such an enhanced mechanical and wound healing feature and may offer an alternative approach for wound healing treatment

Photo-crosslinkable chitosan and gelatin-based nanohybrid bioinks for extrusion-based 3D-bioprinting

In the last decade, 3D-bioprinting has attracted attention due to its capability to produce complex scaffolds. The selection of suitable biomaterials for the bioink design is very important for the success of 3D-bioprinting. In this study, chitosan and gelatin were chemically modified into methacrylated chitosan (ChiMA) and methacrylated gelatin (GelMA) with the methacrylic anhydride in order to obtain crosslinking points on the polymeric backbone. The eligible bioinks were formulated with the layered double hydroxide nanoparticles (LDHs). The effect of changing the amount of LDHs on the printability of the bioinks was evaluated by using rheological analysis and printability test with the extrusion-based 3D-bioprinting. The bioinks were crosslinked under UV light. Mechanical, swelling, degradation properties, and cell-adhesion behaviors of the obtained ChiMA/GelMA nanohybrid scaffolds containing LDHs were investigated. Based on the rheology and the printing results, ChiMA/GelMA nanohybrid scaffold containing 5% LDHs (ChiMA-G5) was found to be the optimal bioink. Notably, compression strength, elongation at break, and elastic modulus of ChiMA-G5 scaffold were higher than neat and other ChiMA/GelMA scaffolds. In vitro cell culture studies showed that LDHs do not have any negative effects. These findings indicate that the developed ChiMA-G5 bioink has great potential as a bioink to utilize for tissue engineering applications

Molecular Separation by Using Active and Passive Microfluidic chip Designs: A Comprehensive Review

Abstract Separation and identification of molecules and biomolecules such as nucleic acids, proteins, and polysaccharides from complex fluids are known to be important due to unmet needs in various applications. Generally, many different separation techniques, including chromatography, electrophoresis, and magnetophoresis, have been developed to identify the target molecules precisely. However, these techniques are expensive and time consuming. “Lab‐on‐a‐chip” systems with low cost per device, quick analysis capabilities, and minimal sample consumption seem to be ideal candidates for separating particles, cells, blood samples, and molecules. From this perspective, different microfluidic‐based techniques have been extensively developed in the past two decades to separate samples with different origins. In this review, “lab‐on‐a‐chip” methods by passive, active, and hybrid approaches for the separation of biomolecules developed in the past decade are comprehensively discussed. Due to the wide variety in the field, it will be impossible to cover every facet of the subject. Therefore, this review paper covers passive and active methods generally used for biomolecule separation. Then, an investigation of the combined sophisticated methods is highlighted. The spotlight also will be shined on the elegance of separation successes in recent years, and the remainder of the article explores how these permit the development of novel techniques

Process development for an effective COVID-19 vaccine candidate harboring recombinant SARS-CoV-2 delta plus receptor binding domain produced by Pichia pastoris

Abstract Recombinant protein-based SARS-CoV-2 vaccines are needed to fill the vaccine equity gap. Because protein-subunit based vaccines are easier and cheaper to produce and do not require special storage/transportation conditions, they are suitable for low-/middle-income countries. Here, we report our vaccine development studies with the receptor binding domain of the SARS-CoV-2 Delta Plus strain (RBD-DP) which caused increased hospitalizations compared to other variants. First, we expressed RBD-DP in the Pichia pastoris yeast system and upscaled it to a 5-L fermenter for production. After three-step purification, we obtained RBD-DP with > 95% purity from a protein yield of > 1 g/L of supernatant. Several biophysical and biochemical characterizations were performed to confirm its identity, stability, and functionality. Then, it was formulated in different contents with Alum and CpG for mice immunization. After three doses of immunization, IgG titers from sera reached to > 106 and most importantly it showed high T-cell responses which are required for an effective vaccine to prevent severe COVID-19 disease. A live neutralization test was performed with both the Wuhan strain (B.1.1.7) and Delta strain (B.1.617.2) and it showed high neutralization antibody content for both strains. A challenge study with SARS-CoV-2 infected K18-hACE2 transgenic mice showed good immunoprotective activity with no viruses in the lungs and no lung inflammation for all immunized mice