Postoperatively Noninvasive Optogenetic Stimulation via Upconversion Nanoparticles Enhancing Sciatic Nerve Repair.

The efficacy of electrical stimulation facilitating peripheral nerve regeneration is evidenced extensively, while the associated secondary damage resulting from repeated electrode invasion and indiscriminate stimulation is inevitable. Here, we present an optogenetics strategy that utilizes upconversion nanoparticles (UCNPs) to convert deeply penetrating near-infrared excitation into blue emission, which activates an adeno-associated virus-encoding ChR2 photoresponsive ion channel on cell membranes. The induced Ca2+ flux, similar to the ion flux in the electrical stimulation approach, efficiently regulates viability and proliferation, secretion of nerve growth factor, and neural function of RSC96 cells. Furthermore, deep near-infrared excitation is harnessed to stimulate autologous Schwann cells in situ via a UCNP-composited scaffold, which enhances nerve sprouting and myelination, consequently promoting functional recovery, electrophysiological restoration, and reinnervation of damaged nerves. This developed postoperatively noninvasive optogenetics strategy presents a novel, minimally traumatic, and enduring therapeutic stimulus to effectively promote peripheral nerve repair.

Artificial periosteum promotes bone regeneration through synergistic immune regulation of aligned fibers and BMSC-recruiting phages.

Given the crucial role of periosteum in bone repair, the use of artificial periosteum to induce spontaneous bone healing instead of using bone substitutes has become a potential strategy. Also, the proper transition from pro-inflammatory signals to anti-inflammatory signals is pivotal for achieving optimal repair outcomes. Hence, we designed an artificial periosteum loaded with a filamentous bacteriophage clone named P11, featuring an aligned fiber morphology. P11 endowed the artificial periosteum with the capacity to recruit bone marrow mesenchymal stem cells (BMSCs). The artificial periosteum also regulated the immune microenvironment at the bone injury site through the synergistic effects of biochemical factors and topography. Specifically, the inclusion of P11 preserved inflammatory signaling in macrophages and additionally facilitated the migration of BMSCs. Subsequently, aligned fibers stimulated macrophages, inducing alterations in cytoskeletal and metabolic activities, resulting in the polarization into the M2 phenotype. This progression encouraged the osteogenic differentiation of BMSCs and promoted vascularization. In vivo experiments showed that the new bone generated in the AP group exhibited the most efficient healing pattern. Overall, the integration of biochemical factors with topographical considerations for sequential immunomodulation during bone repair indicates a promising approach for artificial periosteum development. STATEMENT OF SIGNIFICANCE: The appropriate transition of macrophages from a pro-inflammatory to an anti-inflammatory phenotype is pivotal for achieving optimal bone repair outcomes. Hence, we designed an artificial periosteum featuring an aligned fiber morphology and loaded with specific phage clones. The artificial periosteum not only fostered the recruitment of BMSCs but also achieved sequential regulation of the immune microenvironment through the synergistic effects of biochemical factors and topography, and improved the effect of bone repair. This study indicates that the integration of biochemical factors with topographical considerations for sequential immunomodulation during bone repair is a promising approach for artificial periosteum development.

Ratiometric fluorescence detection of dopamine based on copper nanoclusters and carbon dots.

Nanoclusters for fluorescence detection are generally comprised of rare and expensive noble metals, and the nanoclusters based on more affordable transition metal have attracted increasing attention. This study designed a ratiometric fluorescent probe to detect dopamine (DA), an important neurotransmitter. With carbon dots encapsulated within silica (CDs@SiO2) as the reference, the emitted reference signal was almost unchanged due to the protection of inert silicon shell. Meanwhile, copper nanoclusters modified with 3-aminophenyl boronic acid (APBA-GSH-CuNCs) provided the sensing signal, in which the phenylboric acid could specifically recognize the cis-diol structure of DA, and caused the fluorescence quenching by photoinduced electron transfer. This dual emission ratiometric fluorescent probe exhibited high sensitivity and anti-interference, and was able to selectively responded to DA with a linear range of 0-1.4 mM, the detection limit of 5.6 nM, and the sensitivity of 815 mM-1. Furthermore, the probe successfully detected DA in human serum samples, yielding recoveries ranging from 92.5% to 102.7%. Overall, this study highlights the promising potential of this ratiometric probe for detecting DA.

Integrated GelMA and interleukin 8-loaded liposome composite scaffold for endogenous BMSCs recruitment in bone repair.

Bone repair strategies, based on endogenous stem cell recruitment, can effectively avoid immune rejection and the low utilization of exogenous stem cells. Endogenous stem cells can be recruited to the implantation site by loading chemokines onto bone tissue-engineered scaffolds. However, challenges such as unstable chemokine activity and easy inactivation after implantation remain significant. In the present study, composite fiber scaffolds ((IL8@LIP)-GelMA) consisting of Interleukin 8 (IL8) -loaded liposomes and GelMA were constructed by electrospinning and photocrosslinking, and its ability to recruit bone marrow-derived mesenchymal stem cells (BMSCs) and immunomodulatory effect was investigated. Compared to GelMA loaded directly with IL8, scaffolds of (IL8@LIP)-GelMA demonstrated superior protection of IL8 activity, ensuring a slow and continuous release. Both in vivo and in vitro experiments demonstrated that the (IL8@LIP)-GelMA scaffolds effectively recruited BMSCs to the desired sites. Additionally, the (IL8@LIP)-GelMA scaffolds exhibited the capacity to recruit more macrophages to the implantation site. Importantly, they promoted the polarization of macrophages toward the M2 anti-inflammatory phenotype, facilitating the transition from the inflammatory stage to the tissue repair stage. Therefore, (IL8@LIP)-GelMA scaffolds show great potential for cell-free tissue engineering applications and provide insights into the loading mode of growth factors in scaffolds.

Antigen-specific T cell activation through targeted delivery of in-situ generated antigen and calcium ionophore to enhance antitumor immunotherapy.

Recent advances in adoptive T-cell therapy have delivered impressive therapeutic outcomes by instigating enduring anti-tumor responses. Nonetheless, achieving specific T-cell activation remains a challenge due to several factors. Some cancer cells evade T-cell recognition due to the scarcity of tumor-specific T cells and deficiencies in antigen processing or major histocompatibility complex (MHC) presentation. Notably underestimated is the impact of waning T-cell receptor (TCR) expression and the constrained formation of immune synapses (IS) between dendritic cells (DCs) and T cells, impairing T-cell activation. Addressing these complexities, we introduce a pioneering approach featuring the deployment of a gel implant. This implant establishes an on-site antigen reservoir, efficiently targets DCs in lymph nodes, and facilitates calcium ion (Ca2+) delivery. Engineered with controlled swelling, poroelasticity, and resilience, the gel is suitable for surgical implantation. Its ample encapsulation capacity accommodates both photosensitizers and nanoparticles. Upon in situ photothermal irradiation, the gel generates tumor-specific antigens. Furthermore, cationic albumin nanoparticles (cNPs) co-loaded with monophosphoryl lipid A (MPLA) and ionomycin are released, guiding antigens to tumor-draining lymph nodes for DCs maturation. This meticulous process fosters the formation of IS thereby amplifying antigen-specific T-cell activation.

Dendritic Oligoethylenimine Decorated Liposome with Augmented Corneal Retention and Permeation for Efficient Topical Delivery of Antiglaucoma Drugs.

The topically administered glaucoma medications usually encounter serious precorneal drug loss and low corneal penetration, leading to a low bioavailability. In addition, due to the complexity of glaucoma etiology, a single medication is often insufficient. In this work, we report a novel dendritic oligoethylenimine decorated liposome for codelivery of two antiglaucoma drugs, latanoprost and timolol. The liposome showed a uniform nanoscopic particle size, positive surface charge, and excellent dual-drug loading capacity. A prolonged precorneal retention is observed by using this liposomal delivery system. This liposomal delivery system presents increased cellular uptake and tight junctions opening capacity, contributing respectively to the transcellular and paracellular permeation, thereby enhancing the trans-corneal transportation. Following topical administration of one eye drop in brown Norway rats, the dual-drug-loaded liposome formulation resulted in a sustained and effective intraocular pressure reduction as long as 5 days, without inducing ocular inflammation, discomfort, and tissue damage.

Vanadium-Doped Mesoporous Bioactive Glass Promotes Osteogenic Differentiation of rBMSCs via the WNT/ß-Catenin Signaling Pathway.

Pentavalent vanadium [V(V)] has been studied as bioactive ions to improve the bone defect repair; however, its osteogenic promotion mechanism is still not fully understood so far. In this study, a V-doped mesoporous bioactive glass (V-MBG) was prepared, and its effects on osteogenic differentiation of rat bone marrow mesenchymal stem cells (rBMSCs) and potential signaling pathways were investigated. The physicochemical characterization revealed that the incorporation of V slightly reduced the specific surface area and increased the mesoporous pore size, and the abundant mesopores of V-MBG were beneficial to the sustained dissolution of V(V) ions as well as calcium, silicon, and phosphorus ions. Cell proliferation results indicated that the high dilution ratio (>16) V-MBG extract markedly promoted the proliferation of rBMSCs compared with the control group and the same dilution ratio MBG extract. Compared with the same dilution ratio MBG extract, diluted V-MBG extracts markedly promoted the secretion of alkaline phosphatase (ALP) and osteocalcin (OCN) protein at day 7 but insignificantly stimulated the runt-related transcription factor 2 (RUNX2) and vascular endothelial growth factor (VEGF) protein synthesis. In depth, the diluted V-MBG extracts remarkably up-regulated the expression of WNT/ß-catenin pathway direct target genes, including WNT3a, ß-catenin, and AXIN2 genes in contrast to the same dilution ratio MBG extracts, suggesting that the released V(V) ions might promote osteogenic differentiation of rBMSCs via the WNT/ß-catenin signaling pathway.

A dual-targeting peptide for glioblastoma screened by phage display peptide library biopanning combined with affinity-adaptability analysis.

The obstruction of blood-brain barrier (BBB) and the poor specific targeting are still the major obstacles and challenges of targeted nano-pharmaceutical therapy for glioblastoma (GBM) up to now. It is critical to find appropriate targeting ligands that can effectively mediate the nano-pharmaceuticals to penetrate brain capillary endothelial cells (BCECs) and then specifically bind to glioblastoma cells (GCs). Herein, a dual-targeting ligand for GBM was screened by the combination of phage display peptide library biopanning and affinity-adaptability analysis. Based on the acquisition of sub-library of peptide which exhibited the specific affinity to both BCECs and GCs, a comparison parameter of relative affinity was deliberately introduced to evaluate the relative affinity of candidate peptides to U251-MG cells and bEnd.3 cells. The optimized WTW peptide (sequenced as WTWEYTK) was provided with a high relative affinity (RU/B = 2.44), implying that its high affinity to U251-MG cells and moderate affinity to bEnd.3 cells might synergistically promote its receptor-mediated internalization and transport, the dissociation from bEnd.3, and the binding to U251-MG. The results of BBB model trials in vitro showed that the BBB penetration efficiency and GBM accumulation of WTW peptide were significantly higher than those of WSL peptide, GNH peptide, and REF peptide. Results of orthotopic GBM xenograft model assays in vivo also indicated that WTW peptide had successfully penetrated the BBB and improved accumulation in GBM. The screened WTW peptide might be the potential dual-targeting ligand to motivate the advancement of GBM targeted therapy.

Unique Chirality Selection in Neural Cells for D-Matrix Enabling Specific Manipulation of Cell Behaviors.

Manipulating neural cell behaviors is a critical issue to various therapies for neurological diseases and damages, where matrix chirality has long been overlooked despite the proven adhesion and proliferation improvement of multiple non-neural cells by L-matrixes. Here, it is reported that the D-matrix chirality specifically enhances cell density, viability, proliferation, and survival in four different types of neural cells, contrasting its inhibition in non-neural cells. This universal impact on neural cells is defined as "chirality selection for D-matrix" and is achieved through the activation of JNK and p38/MAPK signaling pathways by the cellular tension relaxation resulting from the weak interaction between D-matrix and cytoskeleton proteins, particularly actin. Also, D-matrix promotes sciatic nerve repair effectively, both with or without non-neural stem cell implantation, by improving the population, function, and myelination of autologous Schwann cells. D-matrix chirality, as a simple, safe, and effective microenvironment cue to specifically and universally manipulate neural cell behaviors, holds extensive application potential in addressing neurological issues such as nerve regeneration, neurodegenerative disease treatment, neural tumor targeting, and neurodevelopment.

Identification of a Specific Phage as Growth Factor Alternative Promoting the Recruitment and Differentiation of MSCs in Bone Tissue Regeneration.

Inefficient use and loss of exogenously implanted mesenchymal stem cells (MSCs) are major concerns in MSCs-based bone tissue engineering. It is a promising approach to overcome the above issues by recruiting and regulation of endogenous MSCs. However, there are few substances that can recruit MSCs effectively and specifically to the site of bone injury. In this study, we identified a phage clone (termed P11) with specific affinity for MSCs through phage display biopanning, and further investigated the effects of P11 on the cytological behavior of MSCs and macrophages. The results showed that P11 could bind MSCs specifically and promote the proliferation and migration of MSCs. Meanwhile, P11 could polarize macrophages to the M1 phenotype and significantly changed their morphology, which further enhanced the chemotaxis of MSCs. Additionally, RNA-seq results revealed that P11 could promote the secretion of osteogenesis-related markers in MSCs through the TPL2-MEK-ERK signaling pathway. Altogether, P11 has great potential to be used as growth factor alternatives in bone tissue engineering, with the advantages of cheaper and stable activity. Our study also advances the understanding of the effects of phages on macrophages and MSCs, and provides a new idea for the development in the field of phage-based tissue engineering.

Study on the preparation of Interleukin 8 loaded hydrogel fiber and regulation on recruitment of stem cells.

The high wastage rate and low survival rate of seed cells in conventional bone tissue engineering (BTE) are always a challenge for tissue regeneration. Constructing scaffolds that could continuously recruit endogenous stem cells is considered a novel way to promote tissue repair. In this study, a GelMA fiber hydrogel membrane loaded interleukin 8 (IL8) (IL8-GelMA), was prepared via electrostatic spinning technology. Compared with Gelatin fiber, GelMA fiber possessed a smooth morphology with nanoscale diameter and better physical properties including hydrophilicity, elastic modulus, swelling rate and degradation rate. In addition, IL8-GelMA fiber membranes could lead an osteogenic differentiation of BMSCs. Moreover, the results of chemotaxis experiment demonstrated that both IL8 and IL8-GelMA fiber membranes promote the migration of BMSCsin vitro. These results suggested that IL8-GelMA fiber membranes can be used for cell-free scaffold of bone repair, which can not only recruit endogenous BMSCs, but also promote osteogenic differentiation of BMSCs.

Enhanced ectopic bone formation by strontium-substituted calcium phosphate ceramics through regulation of osteoclastogenesis and osteoblastogenesis.

To explore how strontium influences osteoclastogenesis and osteoblastogenesis during material-induced ectopic bone formation, porous strontium-substituted biphasic calcium phosphate (Sr-BCP) and BCP ceramics with equivalent pore structures and comparable grain size and porosity were prepared. In vitro results showed that compared with BCP, Sr-BCP inhibited the osteoclastic differentiation of osteoclast precursors by delaying cell fusion, down-regulating the expression of osteoclast marker genes, and reducing the activity of osteoclast specific proteins, possibly due to the activated ERK signaling pathway but the suppressed p38, JNK and AKT signaling pathways. Meanwhile, Sr-BCP promoted the osteogenic differentiation of mesenchymal stem cells (MSCs) by up-regulating the osteogenic gene expression. Sr-BCP also mediated the expression of important osteoblast-osteoclast coupling factors, as evidenced by the increased Opg/Rankl ratio in mMSCs, and the reduced Rank expression and enhanced EphrinB2 expression in osteoclast precursors. Similar results were observed in an in vivo study based on a murine intramuscular implantation model. The sign of ectopic bone formation was only seen in Sr-BCP at 8 weeks. Compared to BCP, Sr-BCP obviously hindered the formation of TRAP- and CTSK-positive multinucleated osteoclast-like cells during the early implantation time up to 6 weeks, which is consistent with the in vivo PCR results. This suggested that Sr-BCP could clearly accelerate the ectopic bone formation by promoting osteogenesis but suppressing osteoclastogenesis, which might be closely related to the expression of osteoblast-osteoclast coupling factors regulated by Sr2+. These findings may help in the design and fabrication of smart bone substitutes with the desired potential for bone regeneration through modulating both osteoclastic resorption and osteoblastic synthesis.

Combined photothermal-photodynamic therapy by indocyanine green loaded polydopamine nanoparticles enhances anti-mammary gland tumor efficacy.

Various nano-targeted drug delivery systems have been developed for combined photothermal-photodynamic (PTT-PDT) treatment of tumors due to better outcomes compared with monomodality therapy. Here, we constructed a facile two-step method without core templates to obtain indocyanine green (ICG) loaded-hyaluronic acid (HA) surface-coated polydopamine nanoparticles (IIPH). The prepared nanoparticles demonstrated an excellent photothermal conversion capacity and efficient singlet oxygen production. Both in vitro and in vivo studies proved that IIPH could significantly inhibit the growth of tumor by PTT-PDT combinational treatment. All the results indicated that IIPH NPs hold great potential to be utilized as a new photothermal-photodynamic composite for cancer treatment.

Preliminary Study on the Antigen-Removal from Extracellular Matrix via Different Decellularization.

Due to the abundance of bioactive components, surficial decoration with cell-derived extracellular matrix (ECM) is a promising strategy to improve the biological functionality of the tissue engineering scaffolds. However, decellularization is necessary to remove antigenic components in the ECM that may trigger adverse immune response. Freeze-thaw (FT) cycles and treatment with Triton X-100/ammonium hydroxide (TN) are two commonly used decellularization methods for ECM, but their effects on both growth factor retention and antigen removal are still controversial. The objectives of this study are to compare the preservation of ECM texture and beneficial ingredients and the removal of cellular antigens by these two methods. First, the constructs combined bone marrow mesenchymal stem cell-derived ECM and poly(lactic-co-glycolic acid) (PLGA) membrane are prepared and decellularized using FT and TN treatments. Moreover, the effects of decellularization on the ultrastructure and the composition of ECM-decorated PLGA membrane are compared by scanning electron microscope observation and protein quantification. Furthermore, the ECM deposited on PLGA is stripped off and then implanted subcutaneously in rats, and the host macrophage and local lymphocyte responses were investigated. Finally, ECM-decorated porous PLGA scaffolds are implanted into rat calvarial defects, and the new bone formation is evaluated. Our results showed that both methods effectively removed DNA. TN treatment partially retained collagen, glycosaminoglycan, bone morphogenetic protein-2, and vascular endothelial growth factor, and better preserved structural integrity than FT treatment. ECM implants decellularized by both methods induced a mild host response after subcutaneous implantation. Although the total content of residual DNA in the two ECMs digested by the DNA enzyme seemed to be similar and very low, the interfaces between implanted materials and natural tissues in the TN group recruited lower numbers of CD68+ macrophages, CD68+CD86+ (M1) macrophages, and CD4+ T lymphocytes than that in FT group, implying that there exist other ECM antigens to influence immune response besides DNA. Furthermore, ECM-decorated scaffolds decellularized by TN treatment induced greater bone formation than that of bare scaffolds in vivo, demonstrating the effective retention of ECM bioactive components after decellularization. This study showed that TN treatment was a more effective and safer decellularization method than FT cycles. Impact statement Decellularization is a prerequisite for extracellular matrix (ECM) application, but there is still no standard for its selection. This study demonstrated that detergent treatment was more effective than freeze-thaw (FT) cycles in removing ECM antigens besides DNA, and the prepared ECM elicited a milder allogenic immune response, which ensured the safety of ECM. Moreover, detergent better preserved the ECM integrity than FT cycles, and effectively retained growth factors, and the decellularized ECM-decorated scaffolds significantly promoted bone repair, which ensured the effectiveness of ECM. This study provides the theoretical and experimental bases for the decellularization strategy of ECM-modified tissue engineering scaffolds.

Coordination of Osteoblastogenesis and Osteoclastogenesis by the Bone Marrow Mesenchymal Stem Cell-Derived Extracellular Matrix To Promote Bone Regeneration.

Extracellular matrix (ECM)-based therapies have been developed to improve bone repair because of their abundance of bioactive components. Besides the osteogenic promotion and the immune response, the potential effect of the ECM on the coordination between osteoblastogenesis and osteoclastogenesis in vivo should also deserve great attention because both osteoblasts and osteoclasts get involved in bone regeneration and are critical for the final repair outcome. Herein, based on our previous study on decellularization, antigen removal, and growth factor retention, porous poly (lactic-co-glycolic acid) (PLGA) scaffolds decorated with the bone marrow mesenchymal stem cell (BMSC)-derived ECM were prepared, and the functions of the ECM on BMSC osteogenic differentiation and osteoclastogenesis in vitro were preferentially investigated. Afterward, bone regeneration and osteoclast formation in vivo induced by ECM-decorated PLGA scaffolds were further studied. The in vitro tests revealed that ECM-decorated PLGA scaffolds obviously facilitated BMSC proliferation and osteogenic differentiation. However, when osteoclast precursors were cultured on the BMSC-derived ECM, the number and size of osteoclasts, expression of cathepsin K and matrix metalloproteinase 9, and tartrate-resistant acid phosphatase activity were notably decreased, accompanied by the reduction in the reactive oxygen species (ROS) level. Interestingly, the addition of exogenous hydrogen peroxide elevated the osteoclast amount on the ECM and up-regulated the resorption-related enzyme levels, implying that the repressive effect of the BMSC-derived ECM on osteoclasts may be related to the intracellular ROS. After implantation into calvarial defects, the ECM-decorated PLGA scaffolds significantly increased bone volume and bone mineral density compared with bare PLGA scaffolds and did not stimulate the overmuch formation of osteoclasts in vivo. This study evidenced that the BMSC-derived ECM may coordinate osteoblastogenesis and osteoclastogenesis and promote favorable bone formation without stimulating bone resorption.

MBG/ PGA-PCL composite scaffolds provide highly tunable degradation and osteogenic features.

It remains a challenge to achieve satisfactory balance between biodegradability and osteogenic capacity in biosynthetic bone grafts. In this study, we aimed to address this challenge by incorporating mesoporous bioactive glass (MBG) into poly(caprolactone-co-glycolide) (PGA-PCL) at gradient ratios. MBG/PGA-PCL (PGC/M) scaffolds with MBG incorporation ratio at 0, 10%, 25% and 40% (PGC/M0-40) were synthesized using a modified solvent casting-particulate leaching method, and their physiochemical and biological properties were comprehensively evaluated. PGC/M scaffolds exhibited highly perforated porous structure with a large-pore size of 300-450 µm, with ordered MBGs of around 6.0 nm mesopores size uniformly dispersed. The increase in MBG incorporation ratio significantly improved the scaffold surface hydrophilicity, apatite-formation ability and pH stability, increased the weight loss rate while insignificantly influenced the molecular chains degradation of PGA-PCL component, and facilitated the attachment, spreading, viability and proliferation of rat bone marrow stromal cells (rBMSCs) on scaffolds. Moreover, rBMSCs cultured on PGC/M10-40 scaffolds demonstrated enhanced ALP activity and osteogenesis-related gene expression in a MBG dose-dependent manner as compared with those cultured on PGC/M0 scaffolds. When implanted to the rat cranial bone defect, PGC/M25 and PGC/M40 scaffolds induced significantly better bone repair as compared to PGC/M0 and PGC/M10 scaffolds. Besides, the biodegradability of PGC/M scaffolds correlated with the MBG incorporation ratio. These data suggested this novel PGC/M scaffolds as promising bone repair biomaterial with highly tunable hydrophilicity, bioactivity, cytocompatibility, osteogenic activity as well as biodegradability.

Fe(III)-Chelated Polydopamine Nanoparticles for Synergistic Tumor Therapies of Enhanced Photothermal Ablation and Antitumor Immune Activation.

Both the low energy density of near-infrared (NIR) photothermal conversion during treatment and the recurrence and metastasis after local treatment have been the main obstacles and conundrums in polydopamine-mediated tumor photothermal therapy (PTT). Herein, On the basis of the enhancement of NIR absorption by ligand to metal charge transfer (LMCT) in transition-metal complexes and the activation of antitumor immunity by an appropriate concentration of Fe(III) ions, Fe(III)-chelated PDA nanoparticles (Fe-PDA NPs) with high loading and responsive release of iron ions were synthesized through a prechelation-polymerization method. First, Fe(III) chelated with the catechol groups in DA to form a mono-dopa-Fe(III) chelate, and then the polymerization of dopamine was initiated under alkaline conditions. The results revealed that the mono-dopa-Fe(III) chelate was still the main form of the Fe ion existing in Fe-PDA and was able to greatly enhance the light absorption behaviors of PDA in NIR, resulting a superior photothermal conversion ability (η = 55.5%). Moreover, the existence of Fe(III) also gave Fe-PDA a T1-weighted MRI contrast-enhancement performance (r1 = 7.668 mM-1 s-1) and it would enable the accurate ablation of primary tumors in vivo with Fe-PDA under NIR irradiation by means of the guidance of MRI and thermal imaging. Furthermore, Fe-PDA exhibited better H2O2-responsive biodegradability in comparison to PDA and easily released Fe ions in tumors, which could effectively promote the tumor-associated macrophage (TAM) repolarization to the M1 mode. TAM repolarization combined with the immunogenic cell death (ICD) induced by PTT could effectively enhance the efficacy of immunotherapy, preventing tumor recurrence and metastasis. The design of Fe-PDA nanoparticles should provide more inspiration for structural and functional improvements of melanin-based materials in tumor suppression.

Preparation and In Vitro Evaluation of Thermosensitive Liposomes Targeting Ovarian Cancer.

INTRODUCTION: Liposomes have been widely used in drug delivery systems because the encapsulation of liposomes changes the biological distribution profile and improves the therapeutic indices of various drugs. Thermosensitive liposomes have been proven to be a precise and effective method for cancer therapy in many preclinical studies. However, the lack of specific targeting ability to cancer cells limited their application in safe and efficient chemotherapy. METHODS: In the present study, an ovarian targeting ligand namely WSGFPGVWGASVK (WSG) screened by phage display in vivo was grafted on the thermosensitive phospholipids to prepare the liposomes targeting ovarian cancer cells. WSG was first grafted onto the hydrophilic terminal of DSPEPEG2000 molecules, and then the WSG modified thermosensitive liposomes (WSG-Lipo) were prepared by thin-film hydration method. Doxorubicin hydrochloride (DOX) was used as a model drug to investigate the drug release behavior of liposomes at different temperatures. The specificity of liposomes to SKOV-3 cells was studied by cell uptake in vitro. RESULTS: The WSG-Lipo-DOX could release more DOX at 42°C than at 37°C, showing stronger specificity to SKOV-3 cells and thus selectively inhibiting SKOV-3 cells activity in vitro. CONCLUSION: The active targeting liposome showed potential in improving the specificity of thermosensitive liposomes and would be applied in the chemotherapy combined with a thermotherapy.

Cu-Chelated polydopamine nanoparticles as a photothermal medium and "immunogenic cell death" inducer for combined tumor therapy.

Chemodynamic therapy (CDT) and photothermal therapy (PTT) have been powerful technologies for tumor ablation. However, how to realize efficient CDT and PTT synergetic tumor ablation through a safe and intelligent system, remains a topic of great research value. Herein, a novel Cu-chelated polydopamine nano-system (Cu-PDA) with surface PEGylation and folate (FA) targeting modification (Cu-PDA-FA) was presented as a photothermal agent (PTA), Fenton-like reaction initiator and "immunogenic cell death" inducer to mediate PTT/CDT synergistical tumor therapy and antitumor immune activation. Primarily, the prepared Cu-PDA NPs possessed elevated photothermal conversion efficiency (46.84%) under the near-infrared (NIR) irradiation, bringing about hyperthermic death of tumor cells. Secondly, Cu-PDA catalyzed the generation of toxic hydroxyl radicals (˙OH) in response to the specific tumor microenvironment (TME) with the depletion of GSH, killing tumor cells with high specificity. Interestingly, the increase in local tumor temperature caused by PTT availed the production of ˙OH, and then the produced toxic ˙OH further led the tumor cells to be more sensitive to heat via impeding the expression of heat shock protein, so the synergistically enhanced PTT/CDT in tumor therapy could be achieved. Most importantly, the synergistical PTT/CDT could cause tumor cell death in an immunogenic way to generate in situ tumor vaccine-like functions, which were able to trigger a systemic antitumor immune response, preventing recurrence and metastasis without any other adjuvant supplementation. Overall, these Cu-PDA NPs will provide inspiration for the construction of a versatile nanoplatform for tumor therapy.

The role of micro-vibration parameters in inflammatory responses of macrophages cultured on biphasic calcium phosphate ceramics and the resultant influence on osteogenic differentiation of mesenchymal stem cells.

Although in vitro studies have shown that biomaterials and mechanical stimuli can mediate inflammatory responses or regulate osteogenesis of MSCs, the underlying behaviour of the inflammatory response of macrophages on biomaterials mediated by mechanical stimuli, which regulates osteogenesis, is relatively unknown. Thus, it is imperative to explore the role of bionic mechanical stimulation in the biomaterial-mediated inflammatory response of macrophages. In this study, we used osteoinductive biphasic calcium phosphate (BCP) ceramics as the model biomaterial and chose micro-vibration stimulation (MVs) with three variable parameters (frequency, magnitude, and time). Based on orthogonal experiments, nine combinations of MVs parameters were generated, and their effects on the BCP-mediated macrophage inflammatory response were investigated. MVs significantly affected the gene expression and cytokine secretion of macrophages grown on BCP ceramics and further influenced the behaviour of bone marrow mesenchymal stem cells (BMMSCs) in a paracrine manner. Moreover, frequency seemed to be the most dominant factor (compared with magnitude and time) in regulating the inflammatory response of macrophages. The optimal combination of MVs parameters (frequency 10 Hz, magnitude 0.45 g, and time 60 min) could induce a healing-associated M2 phenotype, as evidenced by the downregulated pro-inflammatory gene (Il-1ß, and Tnf-α) expression, the upregulated anti-inflammatory gene (Il10) expression, and the inhibited pro-inflammatory cytokine (Il-1ß and Tnf-α) secretion of macrophages grown on BCP ceramics, and its conditioned medium (CM) could further promote osteogenic differentiation of BMMSCs. These findings provide valuable insights into the mechanical stimulus-mediated macrophage inflammatory response and osteogenesis in the presence of osteoinductive BCP ceramics and allow accurate evaluation of the biological performance of biomaterials in vitro, in order to optimize bone substitute materials to achieve the desired clinical performance.