Gelatin Microspheres Research Articles

Cell Contractile Forces Drive Spatiotemporal Morphing in 4D Bioprinted Living Constructs.

Current 4D materials typically rely on external stimuli such as heat or light to accomplish changes in shape, limiting the biocompatibility of these materials. Here, a composite bioink consisting of oxidized and methacrylated alginate (OMA), methacrylated gelatin (GelMA), and gelatin microspheres is developed to accomplish free-standing 4D bioprinting of cell-laden structures driven by an internal stimulus: cell-contractile forces (CCF). 4D changes in shape are directed by forming bilayer constructs consisting of one cell-free and one cell-laden layer. Human mesenchymal stem cells (hMSCs) are encapsulated to demonstrate the ability to simultaneously induce changes in shape and chondrogenic differentiation. Finally, the capability to pattern each layer of the printed constructs is exhibited to obtain complex geometric changes, including bending around two separate, non-parallel axes. Bioprinting of such 4D constructs mediated by CCF empowers the formation of more complex constructs, contributing to a greater degree of in vitro biomimicry of biological 4D phenomena.

Application of Mg-MOF-loaded gelatin microspheres with osteogenic, angiogenic, and ROS scavenging capabilities in bone defect repair

The management of bone defects, particularly those with irregular geometries resulting from osteoporotic fractures, remains fraught with challenges. Microspheres have emerged as a promising vehicle for tissue engineering, distinguished by their controlled release, safety, and ease of application. Various bioactive components are integrated into microspheres to improve their performance. Metal-organic frameworks, formed from metal ions interconnected by organic ligands, are increasingly utilized in tissue engineering. Specifically, magnesium-based MOFs are notable for their broad applicability; Mg2+ ions are instrumental in bone reconstruction and repair, facilitating osteogenesis, angiogenesis, antibacterial effects, and anti-inflammatory properties. Mg-MOF was synthesized using magnesium chloride and gallic acid, and it was incorporated into gelatin microspheres to create Gel@Mg-MOF composite microspheres. Leveraging gelatin's biocompatibility, controlled release, and biodegradability, the composites' biocompatibility was evaluated through toxicity and adhesion assays. Moreover, the osteogenic and angiogenic potentials of the Gel@Mg-MOF microspheres were assessed, alongside their capacity for ROS scavenging. Results suggest that controlled Mg2+ release from Gel@Mg-MOF microspheres promotes osteogenic activity in RBMSCs and enhances angiogenic potential in HUVECs. Additionally, the gallic acid-containing composite microspheres exhibited antioxidative properties. Collectively, the findings suggest that Gel@Mg-MOF microspheres could provide effective support for bone defect repair, with potential for clinical deployment.

A Review on Dermal Wound Repair and Regeneration Using Antimicrobial-Loaded Microspheres Incorporated into Bovine Collagen Scaffold

In this paper, the developed microsphere-incorporated collagen scaffold presents a promising solution for delivering drugs over wound surfaces in a uniform and sustained manner. The biomaterials utilized in this system are of natural origin, minimizing potential toxicity from core materials, and collagen and gelatin exhibit active wound-healing properties. The collagen scaffold used for the delivery device offers several advantages, including minimizing dressing frequency, facilitating easier examination, and providing added aesthetic value. Furthermore, the protein-based biomaterial scaffold acts as a template for the extracellular matrix in the skin, enhancing the maturation of wounds and enabling the transition to the accelerated production of mature and aligned collagen fibers. The controlled release of antimicrobial drugs through denatured collagens and gelatin microspheres, as well as the efficient healing observed in in vivo studies, demonstrate the potential of this system for effective wound care. Overall, the incorporation of ciprofloxacin-loaded microspheres in porous collagen scaffold offers sustained releases of ciprofloxacin in infected environments, as supported by histological examination showing well-formed epidermis and dermis in the connective tissue of the skin. The system’s ability to heal full-thickness wounds within a significantly shorter time frame compared to antibiotic-incorporated collagen sponges further emphasizes its efficacy in wound healing.

Resorbable Microspheres versus Trisacryl Gelatin Microspheres for Uterine Artery Embolization: A Randomized Controlled Trial.

Background There are insufficient data comparing resorbable microspheres (RMs) with permanent trisacryl gelatin microspheres (TAGMs) for uterine artery embolization (UAE). Purpose To compare therapeutic efficacy and clinical outcomes in participants with symptomatic fibroids after UAE with RMs or TAGMs. Materials and Methods This randomized controlled trial included participants undergoing UAE for symptomatic fibroids at a single institution (from May 2021 to May 2023). Participants were randomized one-to-one to undergo UAE with either RMs or TAGMs. Numeric rating scale pain scores and cumulative fentanyl consumption were assessed for 24 hours after undergoing UAE. Anti-Mullerian hormone was measured to assess effects of UAE on ovarian function. MRI was performed before and 3 months after UAE to evaluate fibroid necrosis and uterine artery recanalization. Repeated variables such as pain were analyzed using Mann-Whitney U test with post hoc Bonferroni correction. Results Sixty female participants (mean age, 45.7 years ± 3.6 [SD]) completed the study, with 30 in each group. No evidence of a difference in pain scores was observed between groups (P > .99). Moreover, there was no evidence of a difference in the total fentanyl consumption at 24 hours after UAE between groups (median: RMs, 423 [IQR, 330-530] vs TAGMs, 562 [IQR, 437-780]; P = .15). Serum anti-Mullerian hormone 3 months after UAE showed no evidence of a difference between groups (RMs vs TAGMs, 0.71 ng/mL ± 0.73 vs 0.49 ng/mL ± 0.45, respectively; P = .09). No evidence of a difference in the rate of complete necrosis of the dominant fibroid was observed between groups (97% [29 of 30] for both groups; P > .99). The rate of uterine artery recanalization was higher in RM versus TAGM groups (70% [21 of 30] vs 17% [five of 30], respectively; P < .001). Conclusion UAE with RMs, compared with UAE with TAGMs, showed no evidence of a difference in terms of therapeutic effectiveness or postprocedural pain scores in participants with symptomatic fibroids. Clinical trial registration no. NCT05086770 © RSNA, 2024 See also the editorial by Spies in this issue.

Spatiotemporal delivery of microenvironment responsive hydrogel incorporated with stem cells-loaded porous microspheres for abdominal wall repair

Healing the wounds of abdominal wall defects characterised by severe complications represents a significant clinical challenge. Mesenchymal stem cells (MSC)-based therapies have emerged as a promising strategy for tissue regeneration. However, the low engraftment and survival rates limit their application owing to the complicated wound microenvironment and large wound areas in abdominal wall defects. Inspired by focal biointerfaces, the present research engineered a spatiotemporal delivery microenvironment-responsive therapeutic platform, termed MSC-GSM@HG, for abdominal wall repair. The constructed platform proved capable of dissolving HA-PBA/Gel-DA (HG) hydrogels in response to in vivo inflammatory responses and subsequently releasing MSC-laden gelatine and silk fibroin microspheres (GSMs). Meanwhile, the HG hydrogels can not only protect the MSCs from excessive reactive oxygen species but also exhibit haemostatic and anti-inflammatory properties. Strikingly, this microsphere-releasing hydrogel platform actively enhanced the repair of abdominal wall defects in vivo, by reducing inflammatory response, facilitating angiogenesis and promoting collagen deposition. Therefore, the microenvironment-responsive platform represents a promising strategy for MSC-based therapies for abdominal wall defects through spatiotemporal delivery mechanisms.

Comparing embolic particles for prostatic artery embolization to treat lower urinary tract symptoms in patients with benign prostatic hyperplasia.

Compare the safety and efficacy of polyvinyl alcohol particles (PVA) versus trisacryl gelatin microspheres (Embospheres) versus hydrogel microspheres coated with polyzene-F (Embozenes) for prostatic artery embolization (PAE) to treat patients with benign prostatic hyperplasia (BPH). A single-center prospective cohort study from 2019 to 2023, including patients with international prostate symptom score (IPSS) ≥ 15 and/or quality of life score (QoL) ≥ 4. Allocation to embolic agents was performed chronologically: 100-300 µm PVA (n = 53), followed by 300-500 µm Embospheres (n = 50), and finally, 400 µm Embozenes (n = 50). All patients were evaluated at baseline and at 1 and 6 months after PAE with IPSS/QoL; peak urinary flow rate, post-void residual volume, and prostate volume with ultrasound and prostate-specific antigen. Adverse events and the need for prostatic re-interventions were assessed. There were no significant baseline differences between the three groups except for patient age (62.5 years PVA; 66.1 years Embospheres and 66.6 years Embozenes; p = 0.019). There were no major adverse events and no differences between groups regarding minor adverse events. All outcome measures improved significantly from baseline, with no significant differences between groups. Mean ± standard deviation IPSS/QoL improvement at 6 months: -10.7 ± 7.9/-2.2 ± 1.7 PVA; -10.4 ± 7.3/-2.0 ± 1.5 Embospheres; -10.4 ± 7.0/-2.2 ± 1.6 Embozenes (p = 0.987). Re-intervention rates after 6 months: 9% (n = 5/53) PVA; 14% (n = 7/50) Embospheres; 8% (n = 4/50) Embozenes (p = 0.591). PAE with PVA particles, Embospheres, and Embozenes is equally safe and effective in treating BPH-related lower urinary tract symptoms. This is the first prospective study showing equivalence between the most frequently used embolic agents for prostatic artery embolization. Different particles can be used interchangeably for prostatic artery embolization. The improvements in measured metrics were the same between groups, with no differences in adverse events. The need for prostatic medication and re-intervention rates were the same at 1 and 6 months after embolization.

Mechanical Properties, Drug Release, Biocompatibility, and Antibacterial Activities of Modified Emulsified Gelatin Microsphere Loaded with Gentamicin Composite Calcium Phosphate Bone Cement In Vitro.

Bone defects are commonly addressed with bone graft substitutes; however, surgical procedures, particularly for open and complex fractures, may pose a risk of infection. As such, a course of antibiotics combined with a drug carrier is often administered to mitigate potential exacerbations. This study involved the preparation and modification of emulsified (Em) crosslinking-gelatin (gel) microspheres (m-Em) to reduce their toxicity. The antibiotic gentamicin was impregnated into gel microspheres (m-EmG), which were incorporated into calcium phosphate bone cement (CPC). The study investigated the effects of m-EmG@CPC on antibacterial activity, mechanical properties, biocompatibility, and proliferation and mineralization of mouse progenitor osteoblasts (D1 cells). The average size of the gel microspheres ranged from 22.5 to 16.1 μm, with no significant difference between the groups (p > 0.05). Most of the oil content within the microspheres was transferred through modification, resulting in reduced cytotoxicity. Furthermore, antibiotic-impregnated m-EmG did not compromise the intrinsic properties of the microspheres and exhibited remarkably antibacterial effects. After combining with CPC (m-EmG@CPC), the microspheres did not significantly hinder the CPC reaction and produced the main product, hydroxyapatite (HA). However, the compressive strength of the largest microsphere content of 0.5 wt.% m-EmG in CPC decreased significantly from 59.8 MPa of CPC alone to 38.7 MPa of 0.5m-EmG@CPC (p < 0.05). The 0.5m-EmG@CPC composite was effective against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) in drug release and antibacterial tests. Compared with m-EmG alone, the 0.5m-EmG@CPC composite showed no toxicity to mouse fibroblast cells (L929). Additionally, the proliferation and mineralization of mouse osteoblastic osteoprogenitor cells (D1 cells) did not have a negative impact on the 0.5m-EmG@CPC composite over time in culture compared with CPC alone. Results suggest that the newly developed antibacterial 0.5m-EmG@CPC composite bone cement did not negatively affect the performance of osteoprogenitor cells and could be a new option for bone graft replacement in surgeries.

Expression, characterization, and application of human-like recombinant gelatin

Gelatin is a product obtained through partial hydrolysis and thermal denaturation of collagen, belonging to natural biopeptides. With irreplaceable biological functions in the field of biomedical science and tissue engineering, it has been widely applied. The amino acid sequence of recombinant human-like gelatin was constructed through a newly designed hexamer composed of six protein monomer sequences in series, with the minimum repeating unit being the characteristic Gly-X-Y sequence found in type III human collagen α1 chain. The nucleotide sequence was subsequently inserted into the genome of Pichia pastoris to enable soluble secretion expression of recombinant gelatin. At the shake flask fermentation level, the yield of recombinant gelatin is up to 0.057 g/L, and its purity can rise up to 95% through affinity purification. It was confirmed in the molecular weight determination and amino acid analysis that the amino acid composition of the obtained recombinant gelatin is identical to that of the theoretically designed. Furthermore, scanning electron microscopy revealed that the freeze-dried recombinant gelatin hydrogel exhibited a porous structure. After culturing cells continuously within these gelatin microspheres for two days followed by fluorescence staining and observation through confocal laser scanning microscopy, it was observed that cells clustered together within the gelatin matrix, exhibiting three-dimensional growth characteristics while maintaining good viability. This research presents promising prospects for developing recombinant gelatin as a biomedical material.

Collagen Synthesis During Wound Repair in Infected Albino Rats Using Ciprofloxacin-Loaded Gelatin Microspheres Incorporated into a Collagen Scaffold: A Histological Approach Using Masson’s Trichrome Staining

The production of collagen fibers is essential for wound healing because it creates a scaffold of collagen on which new cells may move and proliferate. It indicates cellular activity and improves strength and flexibility. Collagen synthesis is influenced by a number of factors, including age, health, infection, and diet. Collagen dressings often have the ability to increase the production of collagen. Collagen production can be adversely affected by infected cutaneous wounds, which can result in a delayed healing process, a higher risk of scarring, weakened tissue, and functional impairment. For this reason, in order to speed up wound healing, antimicrobial agents have been added to the collagen scaffold. Furthermore, the prolonged delivery of antimicrobial agent-loaded gelatin microspheres to infected wounds promotes quicker wound healing and effective collagen synthesis in the granulated tissue. These scaffolds may make superior wound dressings in clinical settings in light of this relationship.

Formulation and characterization of quercetin-loaded gelatin microspheres for drug delivery and their evaluation

Formulation and characterization of quercetin-loaded gelatin microspheres for drug delivery and their evaluation

Injectable hydrogel scaffold incorporating microspheres containing cobalt-doped bioactive glass for bone healing.

Injectable in situ-forming scaffolds that induce both angiogenesis and osteogenesis have been proven to be promising for bone healing applications. Here, we report the synthesis of an injectable hydrogel containing cobalt-doped bioactive glass (BG)-loaded microspheres. Silk fibroin (SF)/gelatin microspheres containing BG particles were fabricated through microfluidics. The microspheres were mixed in an injectable alginate solution, which formed an in situ hydrogel by adding CaCl2. The hydrogel was evaluated for its physicochemical properties, in vitro interactions with osteoblast-like and endothelial cells, and bone healing potential in a rat model of calvarial defect. The microspheres were well-dispersed in the hydrogel and formed pores of >100 μm. The hydrogel displayed shear-thinning behavior and modulated the cobalt release so that the optimal cobalt concentration for angiogenic stimulation, cell proliferation, and deposition of mineralized matrix was only achieved by the scaffold that contained BG doped with 5% wt/wt cobalt (A-S-G5Co). In the scaffold containing higher cobalt content, a reduced biomimetic mineralization on the surface was observed. The gene expression study indicated an upregulation of the osteogenic genes of COL1A1, ALPL, OCN, and RUNX2 and angiogenic genes of HIF1A and VEGF at different time points in the cells cultured with the A-S-G5Co. Finally, the in vivo study demonstrated that A-S-G5Co significantly promoted both angiogenesis and osteogenesis and improved bone healing after 12 weeks of follow-up. These results show that incorporation of SF/gelatin microspheres containing cobalt-doped BG in an injectable in situ-forming scaffold can effectively enhance its bone healing potential through promotion of angiogenesis and osteogenesis.

Comparing Deposition Characteristics of Various Embolic Particles Using an In Vitro Prostate Microvasculature Model

PurposeTo compare spatial distributions of radiopaque glass (RG) microspheres, tris-acryl gelatin (TAG) microspheres, and polyvinyl alcohol (PVA) nonspherical foam particles within a planar in vitro microvascular model of the hyperplastic hemiprostate. Materials and MethodsA microvascular model simulating hyperplastic hemiprostate was perfused with a water-glycerin mixture. A microcatheter was positioned distal to the model’s prostatic artery origin, and embolic particles (RG, 50 μm, 100 μm, and 150 μm; TAG, 100–300 μm and 300-500 μm; and PVA, 90–180 μm and 180–300 μm) were administered using a syringe pump. Microscopic imaging and subsequent semantic segmentation were performed to quantify particle distributions within the models. Distal penetrations were quantified statistically via modal analysis of the particle distributions. ResultsMaximum distal penetration was observed for RG microspheres of 50 μm, followed by RG microspheres of 100 μm and then TAG microspheres of 100–300 μm and RG microspheres of 150 μm. TAG microspheres of 300–500 μm, PVA particles of 90–180 μm, and PVA particles of 180–300 μm exhibited the lowest distal penetrations. The distal penetration metrics between groups were significantly different (P < .05) except between TAG microspheres of 100–300 μm and RG microspheres of 150 μm and between PVA particles of 90–180 and 180–300 μm. ConclusionsComparing the spatial distributions of embolic particles in an in vitro microvascular model simulating the hyperplastic hemiprostate revealed that noncompressible particles and those with narrower size calibrations and smaller relative diameters exhibited higher degrees of distal packing. The embolization front was less distinct for particles with wider size calibrations, which resulted in smaller, more distal emboli along with larger, more proximal emboli. Both PVA particles and TAG microspheres of 300–500 μm exhibited relatively low overall distal penetration.

Tissue Regeneration in Infected Wounds of Albino Rats Using Ciprofloxacin-Loaded Gelatin Microspheres Incorporated Collagen Scaffold: A Histological Approach with H&amp;E Staining

A wound care system consisting of ciprofloxacin-loaded gelatin microspheres impregnated in a macroporous collagen scaffold was created to effectively control wound infection and regenerate soft tissue at the wound site. Histological and biochemical alterations were observed in infected wounds treated with these scaffolds in Albino Wistar rats. Furthermore, the study examined the immediate and prolonged release of ciprofloxacin from the scaffolds, as well as their function in eliminating bacterial infections and expediting the process of skin healing and regeneration. The developed technique was followed in the streamlined process of creating these collagen scaffolds. Compared to untreated wounds, the group receiving scaffold treatment experienced a faster rate of wound closure. It was noted that the rate of infections was considerably reduced and that full soft tissue regeneration occurred within 12 days. The development of well-deposited collagen bundles in the treated groups was demonstrated by H&amp;E staining, which verified the flawless regeneration of the dermis and epidermis. The antimicrobial agent-loaded gelatin microspheres impregnated into the porous collagen scaffold demonstrated remarkable soft tissue regeneration and efficient infection control at the wound site.

Gelatin/PLGA Microspheres as a 3D Scaffold for Chondrocytes

Background: Osteoarthritis (OA) degrades cartilage and bone. Osteochondral autograft, allograft, and total replacement knee surgery have limitations, such as prompt immune responses, lack of cartilage tissue obtainability, invasiveness, and a loosening implant that may require further correction. Tissue engineering, which involves injecting chondrocytes into 3D porous scaffold carriers in the joint, seems promising for tissue repair and growth. Objective: To develop gelatin/poly DL-lactide-co-glycolide (PLGA) microspheres as a porous scaffold for chondrocyte carriers. Methods: The double emulsion method is one of the most popular and best methods for forming microspheres. In summary, in the PLGA oil phase, we emulsified a gelatin solution representing the inner aqueous phase. Next, in an external aqueous phase of polyvinyl alcohol (PVA), we emulsified the resultant first emulsion. The double emulsion was stirred to evaporate organic solvent and centrifuged to collect gelatin and PLGA microspheres. Results: The Mastersizer result showed polydispersed particles with 23.53% of the desirable cell injection size range between 1-300 µm. Scanning electronic microscope (SEM) images revealed spherical and porous microspheres with smooth surfaces. The average absolute zeta potential value was -30.7±4.895, indicating stable preparation. Conclusions: Gelatin and PLAGA polymers worked together to make 3D scaffold microspheres that were the right size, had the right number of holes, and were strong.

Effect of Microsphere Concentration on Catechin Release from Microneedle Arrays.

In this work, microspheres were developed by cross-linking glutaraldehyde in an aqueous gelatin solution with a surfactant and solvent. A poly(vinyl alcohol) (PVA) solution was produced and combined with catechin-loaded microspheres. Different microsphere concentrations (0%, 5%, 10%, and 15%) were applied to the PVA microneedles. The moisture content, particle size, swelling, and drug release percentage of microneedles were studied using various microsphere concentrations. Fourier transform infrared and scanning electron microscopy (SEM) investigations validated the structure of gelatin microspheres as well as their decoration in microneedles. The SEM scans revealed that spherical microspheres with a wrinkled and folded morphology were created, with no physical holes visible on the surface. The gelatin microspheres generated had a mean particle size of 20-30 μm. Ex vivo release analysis indicated that microneedles containing 10% microspheres released the most catechin, with 42.9% at 12 h and 84.4% at 24 h.

Tannic acid-crosslinked gelatin composite microspheres adsorbed with CQAS or Ca2+ for rapid hemostasis

In the case of massive blood loss due to natural disasters and wars, timely and rapid hemostasis is of great significance to improve the survival rate of injured people. Nevertheless, uncontrolled, noncompressible, and irregular bleeding wounds remain a giant challenge for rapid hemostasis. In this study, the tannic acid-crosslinked gelatin was first obtained by Michael addition reaction, and then the tannic acid-crosslinked gelatin composite microspheres (TGMs) were prepared by the emulsion cross-linking method. TGMs could significantly improve the water absorption and hemostatic performance compared with single component gelatin microspheres (GMs). Increasing the water absorption ratio and introducing blood coagulation factors into composite materials are simple and effective strategies to enhance the hemostatic properties. Therefore, chitosan quaternary ammonium salt (CQAS) and Ca2+ were electrostatic adsorbed to obtain two kinds of functional TGMs, which were respectively CQAS-absorbed TGMs (T2GMs-CQAS) and calcium ion-absorbed TGMs (T2GMs-Ca2+). Notably, T2GMs-CQAS, and T2GMs-Ca2+ could absorb water rapidly within 3 seconds, in addition, especially the water absorption ratio of T2GMs-CQAS could reach 2.95 times compared with GMs. Benefited from rapid water absorption, coagulation pathway activation, and red blood cells aggregation of T2GMs-CQAS and T2GMs-Ca2+, resulting in rapid blood coagulation in vitro. In addition, CQAS and Ca2+ provided strong and intrinsic antibacterial activity due to positive charge. Moreover, in the tail amputation and liver hemostatic models, T2GMs-CQAS and T2GMs-Ca2+ demonstrated superior hemostatic effects compared to commercial Yunnan Baiyao®. In conclusion, T2GMs-CQAS and T2GMs-Ca2+ have potential applications as hemostatic dressings in uncontrolled, noncompressible, and irregular bleeding wounds.

MG53/GMs/HA-Dex neural scaffold promotes the functional recovery of spinal cord injury by alleviating neuroinflammation

The adverse microenvironment, including neuroinflammation, hinders the recovery of spinal cord injury (SCI). Regulating microglial polarization to alleviate neuroinflammation at the injury site is an effective strategy for SCI recovery. MG53 protein exerts obvious repair ability on multiple tissues damage, but with short half-life. In this study, we composited an innovative MG53/GMs/HA-Dex neural scaffold using gelatin microspheres (GMs), hyaluronic acid (HA), and dextran (Dex) loaded with MG53 protein. This novel neural scaffold could respond to MMP-2/9 protein and stably release MG53 protein with good physicochemical properties and biocompatibility. In addition, it significantly improved the motor function of SCI mice, suppressed M1 polarization of microglia and neuroinflammation, and promoted neurogenesis and axon regeneration. Further mechanistic experiments demonstrated that MG53/GMs/HA-Dex hydrogel inhibited the JAK2/STAT3 signaling pathway. Thus, this MG53/GMs/HA-Dex neural scaffold promotes the functional recovery of SCI mice by alleviating neuroinflammation, which provides a new intervention strategy for the neural regeneration and functional repair of SCI.

Emulsion template fabricated heterogeneous bilayer gelatin-based scaffolds with sustained-delivery of lycium barbarum glycopeptide for periodontitis treatment

Periodontitis is a chronic inflammatory disease raising the risks of tooth-supporting structures destruction and even tooth loss. The way to reconstruct periodontal bone tissues in inflammatory microenvironment has been long in demand for periodontitis treatment. In this study, the lycium barbarum glycopeptide (LbGP) loaded gelatin-based scaffolds were fabricated for periodontitis treatment. Gelatin microspheres with suitable size were prepared by emulsification and gathered by oxidized sodium alginate to prepare heterogeneous bilayer gelatin-based scaffolds, and then they were loaded with LbGP. The prepared scaffolds possessed interconnected porous microstructures, good degradation properties, sufficient mechanical properties, sustained release behavior and well biocompatibility. In vitro experiments suggested that the LbGP loaded gelatin-based scaffolds could inhibit the expression of inflammatory factors (IL-1β, IL-6, and TNF-α), promote the expression of anti-inflammatory factor (IL-10), and the expression of osteogenic markers (BMP2, Runx2, ALP, and OCN) in PDLSCs under the LPS-stimulated inflammatory microenvironment. Moreover, in rat periodontitis models, the LbGP gelatin-based scaffolds would reduce the alveolar bone resorption of rats, increase the collagen fiber content of periodontal membrane, alleviate local inflammation and improve the expression of osteogenesis-related factors. Therefore, the LbGP loaded gelatin-based scaffolds in this study will provide a potential therapeutic strategy for periodontitis treatment.

Preparation and mechanism study of hydrogen bond induced enhanced composited gelatin microsphere probe

Fluorescent probes offer rapid and efficient detection of metal ions. However, their properties, including high biotoxicity and low detection limits, often limit their utility in biological systems. In this study, we used a microfluidic approach to fabricate photocrosslinked gelatin microspheres with a micropore, providing a straightforward method for loading fluorescent probes into these microspheres based on the adsorption effect and hydrogen bonding interaction. The gelatin microsphere loaded probes, GelMA/TPA-DAP and GelMA/TPA-ISO-HNO were designed and obtained. The results show that these probes exhibit obviously low biotoxicity compared to the original molecular probes TPA-DAP and TPA-ISO-HNO. Simultaneously, it is found that GelMA/TPA-DAP and GelMA/TPA-ISO-HNO have better detection sensitivity, the detection limits are 35.4 nM for Cu2+, 16.5 nM for Co2+ and 20.5 nM for Ni2+ for GelMA/TPA-DAP probe. Compared to the original TPA-DAP they are improved by 37.2 %, 26.3 % and 22.6 % respectively. The corresponding coordination constants were 10.8 × 105, 4.11×105 and 6.04×105, which is larger than homologous TPA-DAP. Similar results were also verified in the GelMA/TPA-ISO-HNO probe. The mechanism was investigated in detail by theoretical simulations and advanced spectral analysis. The density functional theory (DFT) simulations show that the probes are anchored inside the microspheres and the molecular structure is modified due to the hydrogen bonding interaction between the microsphere and the molecular probe, which makes GelMA/TPA-DAP exhibit stronger coordination capacity with metal ions than homologous TPA-DAP. In addition, the adsorption effect also provided some synergistic enhancement contribution. Meanwhile, cellular experiments have also shown that the composite microspheres can improve the biocompatibility of the probe and will provide a wider range of applications towards bioassay. This simple and effective method will provide a convenient way to improve the performance of fluorescent probes and their biological applications.

Gelatin Microspheres Based on H8-Loaded Macrophage Membrane Vesicles to Promote Wound Healing in Diabetic Mice.

Diabetic wound healing remains a worldwide challenge for both clinicians and researchers. The high expression of matrix metalloproteinase 9 (MMP9) and a high inflammatory response are indicative of poor diabetic wound healing. H8, a curcumin analogue, is able to treat diabetes and is anti-inflammatory, and our pretest showed that it has the potential to treat diabetic wound healing. However, H8 is highly expressed in organs such as the liver and kidney, resulting in its unfocused use in diabetic wound targeting. (These data were not published, see Table S1 in the Supporting Information.) Accordingly, it is important to pursue effective carrier vehicles to facilitate the therapeutic uses of H8. The use of H8 delivered by macrophage membrane-derived nanovesicles provides a potential strategy for repairing diabetic wounds with improved drug efficacy and fast healing. In this study, we fabricated an injectable gelatin microsphere (GM) with sustained MMP9-responsive H8 macrophage membrane-derived nanovesicles (H8NVs) with a targeted release to promote angiogenesis that also reduces oxidative stress damage and inflammation, promoting diabetic wound healing. Gelatin microspheres loaded with H8NV (GMH8NV) stimulated by MMP9 can significantly facilitate the migration of NIH-3T3 cells and facilitate the development of tubular structures by HUVEC in vitro. In addition, our results demonstrated that GMH8NV stimulated by MMP9 protected cells from oxidative damage and polarized macrophages to the M2 phenotype, leading to an inflammation inhibition. By stimulating angiogenesis and collagen deposition, inhibiting inflammation, and reducing MMP9 expression, GMH8NV accelerated wound healing. This study showed that GMH8NVs were targeted to release H8NV after MMP9 stimulation, suggesting promising potential in achieving satisfactory healing in diabetic treatment.