The effects of stiffness on the specificity and avidity of antibody-coated microcapsules with target cells are strongly shape dependent.

Antibody modification is a common method for endowing drug carriers with the ability to target specific cells. Recent studies suggest that the efficacy of these antibody-modified drug carriers is closely related to their physicochemical properties, such as size, shape, stiffness, charge, and surface chemistry. In this study, we functionalized microcapsules with antibodies to investigate the combined effect of shape and stiffness on their targeting ability.

Gelatin/Hyaluronic Acid Photocrosslinked Double Network Hydrogel with Nano-Hydroxyapatite Composite for Potential Application in Bone Repair.

The application of hydrogels in bone repair is limited due to their low mechanical strength. Simulating bone extracellular matrix, methylacrylylated gelatin (GelMA)/methylacrylylated hyaluronic acid (HAMA)/nano-hydroxyapatite(nHap) composite hydrogels were prepared by combining the double network strategy and composite of nHap in this study. The precursor solutions of the composite hydrogels were injectable due to their shear thinning property.

Locally delivered modified citrus pectin - a galectin-3 inhibitor shows expected anti-inflammatory and unexpected regeneration-promoting effects on repair of articular cartilage defect.

Treating the concomitant inflammation in the process of injury and repair, and simultaneously promoting cartilage regeneration is very important for the repair of articular cartilage (AC) defects. Nevertheless, this remains a massive challenge. To address this issue, a collagen membrane-based modified citrus pectin (MCP) delivery system (MCP-C) was developed in this study by targeting galectin-3 (Gal-3), an upstream proinflammatory factor.

The effect of blending poly (l-lactic acid) on in vivo performance of 3D-printed poly(l-lactide-co-caprolactone)/PLLA scaffolds.

Blending poly (l-lactic acid, PLLA) with poly (l-lactide-co-caprolactone, PLCL) is an effective strategy for developing new PLCL/PLLA blend based biomaterials. However, the effect of PLLA on in vivo performance of PLCL/PLLA blends is unclear yet. To address this issue, in this study, the effect of PLLA on in vivo biodegradability and biocompatibility of 3D-printed scaffolds of PLCL/PLLA blend was investigated.

Rational engineering of biomimetic flavylium fluorophores for regulating the lysosomal and mitochondrial localization behavior by pH-induced structure switch and application to fluorescence imaging.

Mitochondria and lysosomes, as the important subcellular organelles, play vital roles in cell metabolism and physiopathology. However, there is still no general method to precisely regulate the lysosomal and mitochondrial localization behavior of fluorescent probes except by selecting specific targeting groups. Herein, we proposed a pH-induced structure switch (pHISS) strategy to solve this tricky puzzle.

Three-Dimensional Printing Self-Healing Dynamic/Photocrosslinking Gelatin-Hyaluronic Acid Double-Network Hydrogel for Tissue Engineering.

Three-dimensional (3D) printing technology has great potential for constructing structurally and functionally complex scaffold materials for tissue engineering. Bio-inks are a critical part of 3D printing for this purpose. In this study, based on dynamic hydrazone-crosslinked hyaluronic acid (HA-HYD) and photocrosslinked gelatin methacrylate (GelMA), a double-network (DN) hydrogel with significantly enhanced mechanical strength, self-healing, and shear-thinning properties was developed as a printable hydrogel bio-ink for extrusion-based 3D printing.

Biomimetic Nanocarriers Guide Extracellular ATP Homeostasis to Remodel Energy Metabolism for Activating Innate and Adaptive Immunity System.

Metabolic interventions via targeting intratumoral dysregulated metabolism pathways have shown promise in reinvigorating antitumor immunity. However, approved small molecule immunomodulators often suffer from ineffective response rates and severe off-target toxicity. ATP occupies a crucial role in energy metabolism of components that form the tumor microenvironment (TME) and influences cancer immunosurveillance.

Design of a UCST Polymer with Strong Hydrogen Bonds and Reactive Moieties for Facile Polymer-Protein Hybridization.

Polymer-protein hybrids have been extensively used in biomedical fields. Polymers with upper critical solution temperature (UCST) behaviors can form a hydrated coacervate phase below the cloud point (), providing themselves the opportunity to directly capture hydrophilic proteins and form hybrids in aqueous solutions. However, it is always a challenge to obtain a UCST polymer that could aggregate at a high temperature at a relatively low concentration and also efficiently bind with proteins.

Hyaluronic Acid Hydrogel with Adjustable Stiffness for Mesenchymal Stem Cell 3D Culture via Related Molecular Mechanisms to Maintain Stemness and Induce Cartilage Differentiation.

The stemness and differentiation characteristics of bone marrow mesenchymal stem cells (BMSCs) in three-dimensional (3D) culture are of great significance for stem cell therapy and cartilage tissue engineering repair. Moreover, due to their mechanical sensitivity, scaffold materials play important roles in various cell behaviors in 3D culture. In this study, the mechanical strength of hydrogel scaffolds was adjusted by changing the molecular weight of hyaluronic acid (HA).

Blending with Poly(l-lactic acid) Improves the Printability of Poly(l-lactide--caprolactone) and Enhances the Potential Application in Cartilage Tissue Engineering.

Poly(l-lactide--caprolactone) (PLCL, 50:50) has been used in cartilage tissue engineering because of its high elasticity. However, its mechanical properties, including its rigidity and viscoelasticity, must be improved for compatibility with native cartilage. In this study, a set of PLCL/poly(l-lactic acid) (PLLA) blends was prepared by blending with different mass ratios of PLLA that range from 10 to 50%, using thermoplastic techniques.

A Gelatin-Hyaluronic Acid Double Cross-Linked Hydrogel for Regulating the Growth and Dual Dimensional Cartilage Differentiation of Bone Marrow Mesenchymal Stem Cells.

Owing to its unique physiochemical properties similar to the extracellular matrix (ECM), three-dimensional (3D) crosslinked hydrogels are widely studied materials for tissue engineering. In this study, to mimic the ECM microenvironment, a two-step covalent cross-linking with hyaluronic acid and gelatin was performed to form an interpenetrating polymer network structure. Gelatin as the first network greatly improved the mechanical strength of the hydrogels, while a hyaluronic acid network as the second network improved the tenacity and biological activity.

Non-mulberry silk fiber-based scaffolds reinforced by PLLA porous microspheres for auricular cartilage: An in vitro study.

Designing clinical applicable polymeric composite scaffolds for auricular cartilage tissue engineering requires appropriate mechanical strength and biological characteristics. In this study, silk fiber-based scaffolds co-reinforced with poly-L-lactic acid porous microspheres (PLLA PMs) combined with either Bombyx mori (Bm) or Antheraea pernyi (Ap) silk fibers were fabricated as inspired by the "steel bars reinforced concrete" structure in architecture and their chondrogenic functions were also investigated. We found that the Ap silk fiber-based scaffolds reinforced by PLLA PMs (MAF) exhibited superior physical properties (the mechanical properties in particular) as compared to the Bm silk fiber-based scaffolds reinforced by PLLA PMs (MBF).

A collagen mimetic peptide-modified hyaluronic acid hydrogel system with enzymatically mediated degradation for mesenchymal stem cell differentiation.

We have successfully designed and synthesized a biomimetic hydrogel system with maleimide-modified hyaluronic acid (HA) as the backbone and conjugated it to the collagen mimetic peptide (GPO)-CG-RGDS. The matrix metalloproteinase (MMP)-sensitive peptide GCRDGPQGI↓WGQDRCG was the cross-linker. HA has high biocompatibility, low immunogenicity, and the capacity to interact with extracellular molecules.

Silk fibroin/collagen/hyaluronic acid scaffold incorporating pilose antler polypeptides microspheres for cartilage tissue engineering.

A silk fibroin/collagen/hyaluronic acid (SF/COL/HA) composite scaffold was prepared via admixing, crosslinking, and lyophilizing processes. We studied its physicochemical and biological properties, such as water absorption, porosity, weight loss, and biocompatibility. The optimal ratio of SF/COL/HA scaffold was 3:6.

Stability, Pharmacokinetics, Biodistribution and Safety Assessment of Folate-Conjugated Pullulan Acetate Nanoparticles as Cervical Cancer Targeted Drug Carriers.

It is recognized that the stability and journey in the body of nanoparticles are important issues for drug formulations. In this study, we prepared folate-conjugated pullulan acetate nanoparticles (FPANs) and epirubicin loaded FPANs (FPA/EPI) using dialysis method. The storage stability of FPANs and FPA/EPI at 4 degrees C could be up to 3 months.

Anti-tumor drug delivery system based on cyclodextrin-containing pH-responsive star polymer: in vitro and in vivo evaluation.

A cyclodextrin-containing pH-responsive star polymer, with cyclodextrin polymer and pH-sensitive poly(2-(dimethylamino)ethyl methacrylate) as the core and poly(ethylene glycol) as the arm, was evaluated as drug carriers in vitro and in vivo. Doxorubicin (DOX) was successfully loaded into the star polymer to form nanoparticles (DOX-NPs) via host-guest interaction. The physicochemical properties such as drug loading content, size, morphology, stability and physical state of DOX-NPs were characterized in detail by (1)H NMR, DLS, SEM and DSC.

[Study of collagen mimetic peptide's triple-helix structure and its thermostability by circular dichroism].

In the present study, the authors explore the triple-helix conformation and thermal stability of collagen mimetic peptides (CMPs) as a function of peptide sequence and/or chain length by circular dichroism(CD). Five CMPs were designed and synthetized varying the number of POG triplets or incorporating an integrin alpha2beta1 binding motif Gly-Phe-Hyp-Gly-Glu-Arg (GFOGER). CD spectroscopy from 260 to 190 nm was recorded to confirm the existence of triple-helix conformation at room temperature, while thermal melting and thermal annealing of triple-helix (thermal unfolding and refolding of triple-helix, respectively) was characterized by monitoring ellipticity at 225 nm as a function of temperature.

Chitosan-coated gold nanorods for cancer therapy combining chemical and photothermal effects.

To develop a novel type of nanoparticle for cancer therapy, gold nanorods (GNRs) are coated with chitosan (CS) derivatives to combine chemical and photothermal effects. Thiol-modified chitosan derivatives chemically conjugated to doxorubicin (DOX) are successfully synthesized and their in vitro effect is evaluated. Functional nanocarriers (DOX-CS-GNR) with good biocompatibility and optical properties are prepared by conjugating chitosan derivatives to GNRs.

Cellular uptake mechanism and intracellular fate of hydrophobically modified pullulan nanoparticles.

The cellular uptake mechanism and intracellular fate of self-assembled nanoparticles (NPs) of cholesterol-modified pullulan (CHSP) by human hepatocellular carcinoma (HepG2) cells were investigated. Covalent conjugation with fluorescein isothiocyanate (FITC) yielded stably labeled CHSP (FITC-CHSP), which was successfully formulated into NPs (mean particle size 63.0 ± 1.

Studies on the toxic interaction mechanism between 2-naphthylamine and herring sperm DNA.

The toxic interaction between 2-naphthylamine (2-NA) and herring sperm deoxyribonucleic acid (hs-DNA) has been thoroughly investigated by UV absorption, fluorescence, and circular dichroism (CD) spectroscopic methods. UV absorption result indicates that 2-NA may intercalate into the stack base pairs of DNA during the toxic interaction of 2-NA with DNA. A fluorescence quenching study shows that DNA quenches the intrinsic fluorescence of 2-NA via a static pathway.

Enhanced uptake and cytotoxity of folate-conjugated mitoxantrone-loaded micelles via receptor up-regulation by dexamethasone.

Folate conjugated amphiphilic polymeric micelles have attracted much attention for active targeted delivery of drugs in folate receptor α (FR-α) positive tumors. However, the efficacy improvement of targeted delivery folate-based nanovehicles was limited by the abundance of FR-α on the surface of tumor cells. Recently, it was found that FR-α expression of Hela cells could be up-regulated by modulators such as dexamethasone, which open a new avenue to enhance the efficiency of targeted delivery from the biological view.

Thiolated chitosan-modified PLA-PCL-TPGS nanoparticles for oral chemotherapy of lung cancer.

Oral chemotherapy is a key step towards 'chemotherapy at home', a dream of cancer patients, which will radically change the clinical practice of chemotherapy and greatly improve the quality of life of the patients. In this research, three types of nanoparticle formulation from commercial PCL and self-synthesized d-α-tocopheryl polyethylene glycol 1000 succinate (PLA-PCL-TPGS) random copolymer were prepared in this research for oral delivery of antitumor agents, including thiolated chitosan-modified PCL nanoparticles, unmodified PLA-PCL-TPGS nanoparticles, and thiolated chitosan-modified PLA-PCL-TPGS nanoparticles. Firstly, the PLA-PCL-TPGS random copolymer was synthesized and characterized.

Double thermal transitions of type I collagen in acidic solution.

Contributed equally to this work. To further understand the origin of the double thermal transitions of collagen in acidic solution induced by heating, the denaturation of acidic soluble collagen was investigated by micro-differential scanning calorimeter (micro-DSC), circular dichroism (CD), dynamic laser light scattering (DLLS), transmission electron microscopy (TEM), and two-dimensional (2D) synchronous fluorescence spectrum. Micro-DSC experiments revealed that the collagen exhibited double thermal transitions, which were located within 31-37 °C (minor thermal transition, T(s) ∼ 33 °C) and 37-55 °C (major thermal transition, T(m) ∼ 40 °C), respectively.