[Effect of Collagen Peptides on Function of Mouse T Lymphocytes under Simulated Microgravity].

OBJECTIVE: To understand the effect of collagen peptides on the function of mouse lymphocytes under simulated microgravity. METHODS: The splenocytes of mice were isolated, and the rotary cell culture system was used to simulate the microgravity. The T lymphocytes were stimulated with mitotic agents, concanavalin A (ConA), and the cells were treated with different concentrations of collagen peptides. The proliferation of lymphocytes and the levels of cytokines in the supernatant were detected. RESULTS: Simulated microgravity could inhibit the proliferation of spleen T lymphocytes and decrease the level of cytokines in the supernatant. Collagen peptides could promote the lymphocyte proliferation and cytokine production in cells cultured under simulated microgravity. CONCLUSION: Collagen peptides may attenuate the inhibitory effect of simulated microgravity on T lymphocytes by regulating the cell proliferation and the secretion of cytokines.

Decellularized Amnion Membrane Triggers Macrophage Polarization for Desired Host Immune Response.

Appropriate regulation of immunomodulatory responses, particularly acute inflammation involving macrophages, is crucial for the desired functionality of implants. Decellularized amnion membrane (DAM) is produced by removing cellular components and antigenicity, expected to reduce immunogenicity and the risk of inflammation. Despite the potential of DAM as biomaterial implants, few studies have investigated its specific effects on immunomodulation. Here, it is demonstrated that DAM can regulate macrophage-driven inflammatory response and potential mechanisms are investigated. In vitro results show that DAM significantly inhibits M1 polarization in LPS-induced macrophages by inhibiting Toll-like receptors (TLR) signaling pathway and TNF signaling pathway and promotes macrophage M2 polarization. Physical signals from the 3D micro-structure and the active protein, DCN, binding to key targets may play roles in the process. In the subcutaneous implant model in rats, DAM inhibits the persistence of inflammation and fibrous capsule formation, while promoting M2 macrophage polarization, thereby facilitating tissue regeneration. This study provides insights into DAM's effect and potential mechanisms on the balance of M1/M2 macrophage polarization in vitro and vivo, emphasizing the immunomodulation of ECM-based materials as promising implants.

Preliminary exploration of the anti-ovarian cancer activity of peptides derived from bovine bone collagen hydrolysate and its related mechanisms.

Ovarian cancer, a malignant tumor that poses a significant threat to women's health, has seen a rise in incidence, prompting the urgent need for more effective treatment. This study primarily aimed to explore the potential of bovine collagen peptides in inhibiting ovarian cancer. The investigation in this study began with the identification of 268 peptide sequences through LC-MS/MS, followed by a screening process using molecular docking techniques to identify potential peptides capable of binding to EGFR. Subsequently, a series of experiments were performed, demonstrating the inhibitory effects of the peptide GPAGADGDRGEAGPAGPAGPAGPR on the proliferation of ovarian cancer cells. Transcriptomic analysis further revealed that this peptide can regulate cholesterol metabolism in ovarian cancer cells. Finally, a combination of time-resolved fluorescence resonance energy transfer, isothermal titration calorimetry, molecular docking, and molecular dynamics simulations were utilized to validate the ability of this peptide to bind to the epidermal growth factor receptor (EGFR) and impede the binding of epidermal growth factor (EGF) and EGFR.

Chlorogenic acid/carboxymethyl chitosan nanoparticle-assisted biomultifunctional hyaluronic acid-based hydrogel scaffolds for burn skin repair.

Burns are a prevalent type of injury worldwide, affecting tens of millions of people each year and significantly impacting the physical and psychological well-being of patients. Consequently, prompt treatment of burn wounds is imperative, with oxidative stress and excessive inflammation identified as primary factors contributing to delayed healing. In recent years, there has been growing interest in in situ crosslinked multifunctional hydrogels as a minimally invasive approach for personalized treatment delivery. To address these, a photocrosslinkable methacryloyl hyaluronic acid hydrogel scaffold embedded with chlorogenic acid/carboxymethyl chitosan nanoparticles (CGA/CMCS-HAMA, CCH), was developed for the treatment of burn wounds. The hydrogel prepared degraded by over 50 % by day 20, demonstrating stability and meeting the therapeutic requirements for burn wounds. Leveraging the extracellular matrix-like properties of HAMA and the antioxidant capabilities of CGA/CMCS NPs, this hydrogel demonstrates the ability to locally and continuously scavenge ROS and inhibit lipid peroxidation, inhibiting ferroptosis. Moreover, hydrogels well modulate the expression of macrophage- and fibroblast-associated inflammatory factors. Additionally, the hydrogel promotes cell adhesion and migration, further supporting the healing process. Overall, this innovative approach offers a safe and promising solution for burn wound treatment, addressing drug breakthrough and safety concerns while being adaptable to various irregular wound types.

Gelatin-Based Hydrogel Functionalized with Dopamine and Layered Double Hydroxide for Wound Healing.

Hydrogels with adhesion properties and a wetted structure are promising alternatives to traditional wound dressing materials. The insufficiency of gelatin hydrogels in terms of their adhesive and mechanical strength limits their application in wound dressings. This work presents the design and preparation of a gelatin-based hydrogel functionalized with dopamine (DA) and layered double hydroxide (LDH). The combination of DA and LDH improves the hydrogel's adhesion properties in terms of interfacial adhesion and inner cohesion. Hydrogels with 8% DA and 4% LDH attained the highest adhesion strength of 266.5 kPa, which increased to 295.5 and 343.3 kPa after hydrophobically modifying the gelatin with octanoyl and decanoyl aldehydes, respectively. The gelatin-based hydrogels also demonstrated a macroporous structure, excellent biocompatibility, and a good anti-inflammatory effect. The developed hydrogels accelerated wound healing in Sprague Dawley rat skin full-thickness wound models.

Electrospun Nanofiber Scaffold for Skin Tissue Engineering: A Review.

Skin tissue engineering (STE) is widely regarded as an effective approach for skin regeneration. Several synthetic biomaterials utilized for STE have demonstrated favorable fibrillar characteristics, facilitating the regeneration of skin tissue at the site of injury, yet they have exhibited a lack of in situ degradation. Various types of skin regenerative materials, such as hydrogels, nanofiber scaffolds, and 3D-printing composite scaffolds, have recently emerged for use in STE. Electrospun nanofiber scaffolds possess distinct advantages, such as their wide availability, similarity to natural structures, and notable tissue regenerative capabilities, which have garnered the attention of researchers. Hence, electrospun nanofiber scaffolds may serve as innovative biological materials possessing the necessary characteristics and potential for use in tissue engineering. Recent research has demonstrated the potential of electrospun nanofiber scaffolds to facilitate regeneration of skin tissues. Nevertheless, there is a need to enhance the rapid degradation and limited mechanical properties of electrospun nanofiber scaffolds in order to strengthen their effectiveness in soft tissue engineering applications in clinical settings. This Review centers on advanced research into electrospun nanofiber scaffolds, encompassing preparation methods, materials, fundamental research, and preclinical applications in the field of science, technology, and engineering. The existing challenges and prospects of electrospun nanofiber scaffolds in STE are also addressed.

Osteogenic effect and mechanism of IL-10 in diabetic rat jaw defect mode.

OBJECTIVE: The aim of this study was to investigate the effect of IL-10 on the phenotype polarization of macrophages and osteogenesis in diabetes mellitus type 2 (T2DM) rat jaw defects. METHODS: Lipopolysaccharide (LPS) and interleukin-10 (IL-10) were chosen to induce the polarization of macrophages. In vitro assessment included wound-healing assay, western blotting, and alizarin red staining after co-culture of the bone marrow-derived mesenchymal stem cells (BMSCs) and induced macrophages. For in vivo study, IL-10 was loaded on GelMA-Heparin and applied to bone defects of the alveolar ridge in diabetic rats, while Bio-Oss Collagen, simple GelMA-Heparin, and blank control groups were set for contrast experiment. The mandibles of rats were processed for micro-computed tomography, histology, and immunohistochemistry 1 week and 4 weeks after the operation. RESULTS: IL-10 induced expression of arginase 1, TGF-ß1, EGR2, and Mannose Receptor (CD206), whereas LPS induced expression of iNOS, TNF-α, IL-6, CD80. The BMSCs co-cultured with macrophages induced by IL-10 showed increased migration, osteogenic differentiation, and mineralization in vitro. Notably, the IL-10-laden GelMA-Heparin group showed quicker new bone formation and a higher M2/M1 ratio of macrophages in the jawbone defect area compared with the control groups. CONCLUSIONS: IL-10 can stably induce macrophages to M2 type, thereby influencing BMSCs and improving the osteogenesis of jaw bone defects.

Preparation and identification of novel antioxidant peptides from camel bone protein.

Collagen hydrolysates are a vital source of bioactive peptides. The objective of this study was to prepare camel bone collagen hydrolysates with antioxidant activity, and to identify the peptides responsible for the antioxidant activity. To this end, single-factor and orthogonal tests were performed to explore the optimum preparation conditions. A hydrolysis time of 5 h, enzyme:substrate ratio of 1200 U/g, pH of 7.0, and a material:water ratio of 1:3.0 were adopted. Subsequently, the hydrolysates were purified using a series of chromatography procedures, and three novel peptides, GPPGPPGPPGPPGPPSGGFDF (hydroxylation), PATGDLTDFLK, and GSPGPQGPPGSIGPQ, possessing antioxidant abilities, were identified from the fraction using liquid chromatography-tandem mass spectrometry. The peptide PATGDLTDFLK showed excellent DPPH scavenging activity (39%) and a good cytoprotective effect on H2O2-induced oxidative stress damage in HepG2 cells with a 21.1% increase observed.

Identification and Characterization of Peptides from Bovine Collagen Hydrolysates that Promote Myogenic Cell Proliferation.

In this study, bovine collagen hydrolysate was purified via a series of chromatograms, and the peptides with the highest activity for promoting myoblast proliferation were identified by LC-MS-MS. It was demonstrated that the peptide GDAGPPGPAGPAGPPGPIG (hydroxylation) could promote C2C12 proliferation (+18.5% ± 0.04, P < 0.05). The certain peptide was capable of regulating the myogenic cell cycle and inhibiting myogenic cell apoptosis. By combining molecular docking, quantitative real-time PCR, and metabonomics, we suggested that the peptide GDAGPPGPAGPAGPPGPIG (hydroxylation) might bind to FGFR1 and affect the expression of genes downstream of FGFR1 and influence protein synthesis to promote myoblast proliferation. The above results showed that the peptides isolated in this study have the potential to alleviate sarcopenia in the elderly.

In situ self-assembly of polydopamine inside injectable hydrogels: antibacterial activity and photothermal therapy for superbug-infected wound healing.

Inspired by the mussel foot proteins, polydopamine nanoparticles (PDA NPs) are often used to design hydrogel wound dressings due to their strong wet adhesion. However, additional antibiotics or nanometal bactericides are always required to enhance their poor antibacterial activity, which will cause drug resistance and toxic side effects. Herein, self-assembly confined PDA NPs (SC-PDA NPs, <50 nm) are employed as a freestanding antibacterial ingredient for constructing an ideal hydrogel wound dressing, which maintains relatively strong reducibility and size effect. Through a rapid gelation (within 10 s) strategy triggered by electrostatic complexation, an antibacterial hydrogel system is obtained, in which the in situ self-assembly of the SC-PDA NPs continues, endowing the gel with outstanding antibacterial activity, especially against methicillin-resistant Staphylococcus aureus (MRSA, >99.9%). With the continuous in situ self-assembly, the size of the PDA NPs increases (>200 nm), eventually giving the gel an efficient photothermal therapy effect. Moreover, the gel presents a relatively strong wet adhesion (63 kPa), superior biocompatibility and non-immunogenicity. This work offers innovative insights into the antibacterial mechanism of SC-PDA NPs and provides a novel design for constructing safe antibacterial hydrogel wound dressings, demonstrating great potential applications in superbug-infected wound healing.

Synergy of Oxygen Vacancies and Acid Sites on N-Doped WO3 Nanobelts for Efficient C-C Coupling Synthesis of Benzoin Isopropyl Ether.

The surface property of a photocatalyst, including surface acid sites and oxygen vacancies, plays a pivotal role in photocatalytic organic synthesis reactions. Benzoin isopropyl ether (BIE) is usually produced via polycondensation of benzaldehyde and catalyzed with highly toxic cyanide. Here, we report a green photocatalytic approach for the selective synthesis of BIE over WO3 driven by a green-light-emitting diode. The improved photocatalytic activity can be attributed to the synergy of oxygen vacancies (VOs) and acid sites over N-doped WO3 nanobelts. The results revealed that reactant molecules were predominantly adsorbed and activated on surface oxygen vacancies (VOSs) and the Brønsted acid promoted the etherification reaction; the introduction of VOs and nitrogen altered the band structure and electronic properties, resulting in improved photocatalytic activity. Our work provides an efficient approach to the selective photocatalytic synthesis of organics over photocatalysts with finely tuned surface properties and band structures via defect and doping engineering.

Nitrogen-doped hydrochars from shrimp waste as visible-light photocatalysts: Roles of nitrogen species.

The increasing shrimp waste production has caused severe environmental problems. In this study, nitrogen-doped hydrochars (NDHCs) were facilely synthesized from shrimp waste and glucose by one-pot hydrothermal carbonization (HTC). The characterizations showed that NDHCs had large surface areas of up to 30.5 m2 g-1 with numerous functional groups on their porous surfaces. The nitrogen content (1.3-2.8%) and species distribution in NDHCs were associated with the amount of added glucose. These NDHCs were applied as visible-light-induced photocatalysts, and their photocatalytic performances were evaluated by methylene blue (MB) degradation. The removal rate of MB reached 88.9% after 1 h of visible light radiation by NDHC-1, which was 2.3 times higher than that of glucose-derived hydrochar (GHC). The mechanism study showed that the improved photoactivity of NDHCs was attributed to the increased adsorption capacity by porous surface and the promoted formation of hydroxyl radicals by synergistic effects of quaternary N and pyrrolic N during photocatalysis. This study offered a green approach to preparing tunable, efficient, and low-cost photocatalyst from waste biomass and insight into the photocatalytic mechanism of hydrochar materials.

Rapid Fabrication of MgNH4PO4·H2O/SrHPO4 Porous Composite Scaffolds with Improved Radiopacity via 3D Printing Process.

Although bone repair scaffolds are required to possess high radiopacity to be distinguished from natural bone tissues in clinical applications, the intrinsic radiopacity of them is usually insufficient. For improving the radiopacity, combining X-ray contrast agents with bone repair scaffolds is an effective method. In the present research, MgNH4PO4·H2O/SrHPO4 3D porous composite scaffolds with improved radiopacity were fabricated via the 3D printing technique. Here, SrHPO4 was firstly used as a radiopaque agent to improve the radiopacity of magnesium phosphate scaffolds. X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS) were used to characterize the phases, morphologies, and element compositions of the 3D porous composite scaffolds. The radiography image showed that greater SrHPO4 contents corresponded to higher radiopacity. When the SrHPO4 content reached 9.34%, the radiopacity of the composite scaffolds was equal to that of a 6.8 mm Al ladder. The porosity and in vitro degradation of the porous composite scaffolds were studied in detail. The results show that magnesium phosphate scaffolds with various Sr contents could sustainably degrade and release the Mg, Sr, and P elements during the experiment period of 28 days. In addition, the cytotoxicity on MC3T3-E1 osteoblast precursor cells was evaluated, and the results show that the porous composite scaffolds with a SrHPO4 content of 9.34% possessed superior cytocompatibility compared to that of the pure MgNH4PO4·H2O scaffolds when the extract concentration was 0.1 g/mL. Cell adhesion experiments showed that all of the scaffolds could support MC3T3-E1 cellular attachment well. This research indicates that MgNH4PO4·H2O/SrHPO4 porous composite scaffolds have potential applications in the bone repair fields.

Application of Electrospinning in Antibacterial Field.

In recent years, electrospun nanofibers have attracted extensive attention due to their large specific surface area, high porosity, and controllable shape. Among the many applications of electrospinning, electrospun nanofibers used in fields such as tissue engineering, food packaging, and air purification often require some antibacterial properties. This paper expounds the development potential of electrospinning in the antibacterial field from four aspects: fiber morphology, antibacterial materials, antibacterial mechanism, and application fields. The effects of fiber morphology and antibacterial materials on the antibacterial activity and characteristics are first presented, then followed by a discussion of the antibacterial mechanisms and influencing factors of these materials. Typical application examples of antibacterial nanofibers are presented, which show the good prospects of electrospinning in the antibacterial field.

Antibacterial Porous Coaxial Drug-Carrying Nanofibers for Sustained Drug-Releasing Applications.

The phenomenon of drug burst release is the main problem in the field of drug delivery systems, as it means that a good therapeutic effect cannot be acheived. Nanofibers developed by electrospinning technology have large specific surface areas, high porosity, and easily controlled morphology. They are being considered as potential carriers for sustained drug release. In this paper, we obtained polycaprolactone (PCL)/polylactic acid (PLA) core-shell porous drug-carrying nanofibers by using coaxial electrospinning technology and the nonsolvent-induced phase separation method. Roxithromycin (ROX), a kind of antibacterial agent, was encapsulated in the core layer. The morphology, composition, and thermal properties of the resultant nanofibers were characterized by scanning electron microscopy (SEM), attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy, differential scanning calorimetry (DSC) and thermogravimetry analysis (TGA). Besides this, the in vitro drug release profile was investigated; it showed that the release rate of the prepared coaxial porous nanofibers with two different pore sizes was 30.10 ± 3.51% and 35.04 ± 1.98% in the first 30 min, and became 92.66 ± 3.13% and 88.94 ± 1.58% after 14 days. Compared with the coaxial nonporous nanofibers and nanofibers prepared by uniaxial electrospinning with or without pores, the prepared coaxial porous nanofibers revealed that the burst release was mitigated and the dissolution rate of the hydrophobic drugs was increased. The further antimicrobial activity demonstrated that the inhibition zone diameter of the coaxial nanofibers with two different pore sizes was 1.70 ± 0.10 cm and 1.73 ± 0.23 cm, exhibiting a good antibacterial effect against Staphylococcus aureus. Therefore, the prepared nanofibers with the coaxial porous structures could serve as promising drug delivery systems.

Extreme Temperature-Tolerant Conductive Gel with Antibacterial Activity for Flexible Dual-Response Sensors.

Flexible sensors based on conductive hydrogel show great potential in electronic skin and human-machine interface. However, pure water in hydrogel inevitably freezes or rapidly evaporates under extreme temperatures, leading to inadequate fulfillment of sensor performances. Herein, a well-designed strategy is reported for fabricating extreme temperature-tolerant gel-based sensors. By immersing a gelatin/polyacrylamide (PAAm)-clay composite (GC) hydrogel into a ZnCl2/water/glycerol system, a phase-transition-tunable gel (PTTGC gel) is obtained with outstanding antifreezing (-82 °C) and long-lasting moisture (70 °C, more than 40 days) properties. Meanwhile, the gel also presents good antibacterial activity and biocompatibility attributing to Zn2+ and gelatin, respectively. Then, a dual-response sensor with a wide operating temperature (-60 to 60 °C) is proposed, presenting high stress and temperature sensitivities and long-term stability. The sensor will meet the needs of the human-machine interface for scientific investigation and data monitoring in polar, desert, etc.

A GelMA-PEGDA-nHA Composite Hydrogel for Bone Tissue Engineering.

A new gelatin methacrylamine (GelMA)-poly (ethylene glycol) diacrylate (PEGDA)-nano hydroxyapatite (nHA) composite hydrogel scaffold was developed using UV photo-crosslinking technology. The Ca2+ from nHA can form a [HO]Ca2+ [OH] bridging structure with the hydroxyl group in GelMA, thereby enhancing the stability. Compared with GelMA-PEGDA hydrogel, the addition of nHA can control the mechanical properties of the composite hydrogel and reduce the degradation rate. In vitro cell culture showed that osteoblast can adhere and proliferate on the surface of the hydrogel, indicating that the GelMA-PEGDA-nHA hydrogel had good cell viability and biocompatibility. Furthermore, GelMA-PEGDA-nHA has excellent injectability and rapid prototyping properties and is a promising 3D printed bone repair scaffold material.

Cell Proliferation Stimulation Ability and Osteogenic Activity of Low Molecular Weight Peptides Derived from Bovine Gelatin Hydrolysates.

It has been recognized that collagen peptides of MW 878 Da (CP1) promote osteoblast proliferation and mineralization. The objective of this study is to identify the peptides responsible for proliferation of osteoblast growth, enhancement of ALP (alkaline phosphatase) activity in osteoblasts and promotion of osteoblast mineralization. To this end, the CP1 were fractioned by a series of chromatography procedures, and 51 peptides from the fraction possessing the most powerful cell proliferation ability were identified by LC-MS-MS. The peptides, GPAGPSGPAGK and GPPGSPGPR, were validated on a simultaneous basis as possessing enhanced bioactivity-inducing properties. In particular, the ALP activity of the cells treated with these two peptides was almost twice that of the control cells. Hydrogen bonds were formed, and the hydrophobic interactions with the EGFR (epidermal growth factor receptor) might be responsible for the osteoblast proliferation activity. On this basis, the two peptides might be potential lead compounds against osteoporosis and osteoarthritis.

Chitosan-Gated Fluorescent Mesoporous Silica Nanocarriers for the Real-Time Monitoring of Drug Release.

We have constructed a novel gated nanocarrier for the real-time monitoring of drug release, consisting of three parts: (i) mesoporous silica nanoparticles (MSNs) as the drug carrier, (ii) chitosan as the nanovalve to block and unlock the pores, and (iii) 1,8-naphthalimide fluorophore as a connecting arm and fluorescent signal source. In the absence of glutathione (GSH), the integrity of the system results in the formation of pores in a closed state and the sulfone would block the intramolecular charge transfer (ICT) process, leading to no fluorescence emission. However, the nucleophilic attack of GSH can cause the removal of the chitosan and recovery of ICT property, thus triggering drug release and green fluorescence emission. The results demonstrate that the change of GSH concentration in vivo or vitro would lead to a change in drug release as well as a concurrent change in fluorescence signal, which can expand the application of our gated nanocarrier for monitoring different drug release in real time.

Cell Growth Stimulation, Cell Cycle Alternation, and Anti-Apoptosis Effects of Bovine Bone Collagen Hydrolysates Derived Peptides on MC3T3-E1 Cells Ex Vivo.

Bovine bone collagen hydrolysates promote bone formation through regulating bone growth. However, the peptide sequences within these isolates have not been characterized. In this study, twenty-nine peptides from bovine bone collagen hydrolysates were purified and identified using nano-HPLC-MS-MS and Peak Studio analysis. HHGDQGAPGAVGPAGPRGPAGPSGPAGKDGR (Deamidation) and GPAGANGDRGEAGPAGPAGPAGPR (Deamidation) enhanced cell viability, inhibited apoptosis, and significantly altered the cell cycle of MC3T3-E1 osteoblast cells. These peptides were selected to perform molecular docking analysis to examine the mechanism underlying these bioactivities. Molecular docking analysis showed that these two peptides formed hydrophobic interactions and hydrogen bonds with epidermal growth factor receptor (EGFR) to activate the EGFR-signaling pathway, which may explain their bioactivity. These findings indicate that these and other similar peptides might be candidates for the treatment of osteoporosis.