Balance between the CMC/ACP Nanocomplex and Blood Assimilation Orchestrates Immunomodulation of the Biomineralized Collagen Matrix.

Calcium phosphate-based biomineralized biomaterials have broad application prospects. However, the immune response and foreign body reactions elicited by biomineralized materials have drawn substantial attention recently, contrary to the immune microenvironment optimization concept. Therefore, it is important to clarify the immunomodulation properties of biomineralized materials. Herein, we prepared the biomineralized collagen matrix (BCM) and screened the key immunomodulation factor carboxymethyl chitosan/amorphous calcium phosphate (CMC/ACP) nanocomplex. The immunomodulation effect of the BCM was investigated in vitro and in vivo. The BCM triggered evident inflammatory responses and cascade foreign body reactions by releasing the CMC/ACP nanocomplex, which activated the potential TLR4-MAPK/NF-κB pathway, compromising the collagen matrix biocompatibility. By contrast, blocking the CMC/ACP nanocomplex release via the blood assimilation process of the BCM mitigated the inflammation and foreign body reactions, enhancing biocompatibility. Hence, the immunomodulation of the BCM was orchestrated by the balance between the CMC/ACP nanocomplex and the blood assimilation process. Controlling the release of the CMC/ACP nanocomplex to accord the biological effects of ACP with the temporal regenerative demands is key to developing advanced biomineralized materials.

Optimizing the biodegradability and osteogenesis of biogenic collagen membrane via fluoride-modified polymer-induced liquid precursor process.

Biogenic collagen membranes (BCM) have been widely used in guided bone regeneration (GBR) owing to their biodegradability during tissue integration. However, their relatively high degradation rate and lack of pro-osteogenic properties limit their clinical outcomes. It is of great importance to endow BCM with tailored degradation as well as pro-osteogenic properties. In this study, a fluoride-modified polymer-induced liquid precursor (PILP) based biomineralization strategy was used to convert the collagen membrane from an organic phase to an apatite-based inorganic phase, thus achieving enhanced anti-degradation performance as well as osteogenesis. As a result, three phases of collagen membranes were prepared. The original BCM in the organic phase induced the mildest inflammatory response and was mostly degraded after 4 weeks. The organic-inorganic mixture phase of the collagen membrane evoked a prominent inflammatory response owing to the fluoride-containing amorphous calcium phosphate (F-ACP) nanoparticles, resulting in active angiogenesis and fibrous encapsulation, whereas the inorganic phase induced a mild inflammatory response and degraded the least owing to the transition of F-ACP particles into calcium phosphate with high crystallinity. Effective control of ACP is key to building novel apatite-based barrier membranes. The current results may pave the way for the development of advanced apatite-based membranes with enhanced barrier performances.

Tumor-Targeted Polydopamine-Based Nanoparticles for Multimodal Mapping Following Photothermal Therapy of Metastatic Lymph Nodes.

Purpose: Lymphadenectomy with lymph node (LN) mapping is essential for surgical removal of solid tumors. Existing agents do not provide accurate multimodal mapping and antitumor therapy for metastatic LNs; therefore, we fabricated a polydopamine (PDA) nanoparticle (NP)-based tumor-targeted LN mapping agent capable of multimodal mapping and guided photothermal therapy (PTT) for metastatic LNs. Materials and Methods: PDA NPs modified with polyethylene glycol (PEG) were obtained by polymerization under alkaline conditions. The PEG-PDA NPs were loaded with the circular tripeptide Arg-Gly-Asp (cRGD) to achieve tumor-targeting capacity and with the fluorescent dye IR820 and magnetic resonance imaging (MRI) contrast Gd(NH2)2 for in situ detection. The resulting cRGD-PEG-PDA@IR820/Gd(NH2)2 (cRGD-PPIG) NPs were tested for their biosafety and metastatic LN mapping ability. They were drained specifically into LNs and selectively taken up by gastric MKN45 cells via αvß3 integrin-mediated endocytosis. Results: This phenomenon enabled MR/optical/near-infrared fluorescence multimodal metastatic LN mapping, guiding the creation of accurate and highly efficient PTT for gastric cancer metastatic LNs in mice. Conclusion: In summary, we fabricated tumor-targeted cRGD-PPIG NPs with MR/optical/near-infrared fluorescence multimodal metastatic LN mapping capacity for surgery and efficient PTT guidance post-surgery.

Manganese-containing polydopamine nanoparticles as theranostic agents for magnetic resonance imaging and photothermal/chemodynamic combined ferroptosis therapy treating gastric cancer.

Gastric cancer (GC) is a serious disease with high morbidity and mortality rates worldwide. Chemotherapy plays a key role in GC treatment, while inevitable drug resistance and systematic side effects hinder its clinical application. Fenton chemistry-based chemodynamic therapy (CDT) has been used as a strategy for cancer ferroptosis, and the CDT efficiency could be enhanced by photothermal therapy (PTT). With the trend of treatment and diagnosis integration, the combination of magnetic resonance imaging (MRI) and CDT/PTT exhibits enormous progress. Herein, we constructed a platform based on PEGylated manganese-containing polydopamine (PDA) nanoparticles, named as PEG-PDA@Mn (PP@Mn) NPs. The PP@Mn NPs were stable and globular. Furthermore, they demonstrated near-infrared (NIR)-triggered PTT and Fenton-like reaction-based CDT effects and T1-weighted MRI capabilities. According to in vitro studies, the PP@Mn NPs trigger ferroptosis in cancer cells by producing abundant reactive oxygen species (ROS) via a Fenton-like reaction combined with PTT. Furthermore, in vivo studies showed that, under MRI guidance, the PP@Mn NPs combined with the PTT at the tumor region, have CDT anti-tumor effect. In conclusion, the PP@Mn NPs could provide an effective strategy for CDT/PTT synergistic ferroptosis therapy for GC.