New Autonomous Water-Enabled Self-Healing Coating Material with Antibacterial-Agent-Releasing Properties

Tannic acid-modified FK506-loaded nanoparticles targeting lymph nodes for acute heart transplant rejection treatment

Significant efforts have been made to deliver immunosuppressants-loaded nanoparticles (NPs) to lymph nodes (LNs) to mitigate transplant rejection. However, conventional administration techniques encounter challenges in enhancing the retention of NPs in the LNs. Attributing the strong affinity of tannic acid (TA) molecules to the elastin of LN conduits, we developed a novel formulation of NPs encapsulating Tacrolimus (FK506), and subsequently modified with TA to produce TA-FNP with a final diameter of approximately 86.07 ± 2.78 nm. These particles could traverse the the intercellular gaps in the lymphatic endothelial cells layers, enter the paracortex through LN capsule-associated conduits, and releases FK506 to inhibit the activation and proliferation of allogeneic T cells. Our finding demonstrated that TA-FNP could accumulate in LNs, significantly increasing the local concentration of FK506 from 69.06 ± 21.96 ng/g to 1041.28 ± 343.59 ng/g compared to the free FK506 treatment group. Subsequently, the therapeutic efficacy of TA-FNP was assessed in heart transplantation model, where treatment with TA-FNP resulted in decreased T cells infiltration within the grafts, reduced rejection grades, and a significant extension of graft survival time. In contrast, FNP without TA showed relatively poor therapeutic outcomes. Consequently, this study reveals a promising strategy utilizing TA to enhance the prolonged retention of FK506 within LNs, underscoring its potential therapeutic application in preventing heart transplant rejection.

Introducing self-healing properties to polyethersulfone (PES) membrane via poly(vinyl alcohol)/ polyacrylic acid (PVA/PAA) surface coating

During membrane filtration, it is inevitable that a membrane will experience physical damage, leading to a loss of its integrity and a decrease in separation efficiency. Hence, the development of a water-responsive membrane capable of healing itself autonomously after physical damage is significantly important in the field of water filtration. Herein, a water-enabled self-healing composite polyethersulfone (PES) membrane was synthesized by coating the membrane surface using a mixed solution composed of poly (vinyl alcohol) and polyacrylic acid (PVA-PAA). The self-healing efficiency of the coated PES membrane was examined based on the changes in water flux at three stages which are pre-damaged, post-damaged, and post-healing. The self-healing process was initiated by the swelling of the water-responsive PVA and PAA, followed by the formation of reversible hydrogen bonds, completing the self-healing process. The coated PES membrane with three layers of PVA-PAA coatings (at 3:1 ratio) demonstrated high water flux and remarkable self-healing efficiency of up to 98.3%. The self-healing capability was evidenced by the morphology of the membrane observed via scanning electron microscope (SEM). The findings of this investigation present a novel architecture approach for fabricating self-healing membranes using PVA-PAA, in addition to other relevant parameters as reported.

Nanoadjuvants Actively targeting lymph node conduits and blocking tumor invasion in lymphatic vessels

Great efforts have been made to manipulate nanoparticles (NPs) with a diameter of 10-100 nm to passively target lymph nodes (LNs) to magnitude anti-tumor activity of T cells. However, no attention has been paid to increasing the retention of NPs with active affinity in order to induce a prolonged release of antigens or molecular adjuvants in the LNs mattering the immune response. Here, we formulated two NPs encapsulated with imiquimod (IMQ), a TLR7/8 agonist, and paclitaxel (PTX) and further modified them with tannic acid (TA), respectively, to generate IMQ NP and PTX NP with a final diameter of approximately 40 nm. Attributing a strong affinity of TA molecules to the elastin of LN conduits, the TA modified IMQ NPs can bypass the gaps in the layer of lymphatic endothelial cells and enter the paracortex through the lymph node capsule-associated (LNC) conduits. Similarly, the TA modified PTX NPs increased delivery of PTX to the metastatic tumor site in LNs, where the tumor-associated antigens were released and presented by conduits-lining dendritic cells to activate T cells. Thus, the NPs with deposition to LN conduits showed excellent performance in preventing lymphovascular invasion of triple-negative breast cancer cells and lung metastasis thereafter. On the contrary, the NPs without TA flowed through the subcutaneous sinus existing LNs directly by efferent lymphatic vessels showing relatively poor therapeutic outcomes. This study reveals that TA may mediate the long retention of antigens and molecular adjuvants to be delivered to deep LNs for developing potent vaccination technology.

Glycidyl Methacrylate-Based Copolymers as Healing Agents of Waterborne Polyurethanes

Self-healing materials and self-healing mechanisms are two topics that have attracted huge scientific interest in recent decades. Macromolecular chemistry can provide appropriately tailored functional polymers with desired healing properties. Herein, we report the incorporation of glycidyl methacrylate-based (GMA) copolymers in waterborne polyurethanes (WPUs) and the study of their potential healing ability. Two types of copolymers were synthesized, namely the hydrophobic P(BA-co-GMAy) copolymers of GMA with n-butyl acrylate (BA) and the amphiphilic copolymers P(PEGMA-co-GMAy) of GMA with a poly(ethylene glycol) methyl ether methacrylate (PEGMA) macromonomer. We demonstrate that the blending of these types of copolymers with two WPUs leads to homogenous composites. While the addition of P(BA-co-GMAy) in the WPUs leads to amorphous materials, the addition of P(PEGMA-co-GMAy) copolymers leads to hybrid composite systems varying from amorphous to semi-crystalline, depending on copolymer or blend composition. The healing efficiency of these copolymers was explored upon application of two external triggers (addition of water or heating). Promising healing results were exhibited by the final composites when water was used as a healing trigger.