Recent advances in near-infrared II imaging technology for biological detection.

Molecular imaging technology enables us to observe the physiological or pathological processes in living tissue at the molecular level to accurately diagnose diseases at an early stage. Optical imaging can be employed to achieve the dynamic monitoring of tissue and pathological processes and has promising applications in biomedicine. The traditional first near-infrared (NIR-I) window (NIR-I, range from 700 to 900 nm) imaging technique has been available for more than two decades and has been extensively utilized in clinical diagnosis, treatment and scientific research. Compared with NIR-I, the second NIR window optical imaging (NIR-II, range from 1000 to 1700 nm) technology has low autofluorescence, a high signal-to-noise ratio, a high tissue penetration depth and a large Stokes shift. Recently, this technology has attracted significant attention and has also become a heavily researched topic in biomedicine. In this study, the optical characteristics of different fluorescence nanoprobes and the latest reports regarding the application of NIR-II nanoprobes in different biological tissues will be described. Furthermore, the existing problems and future application perspectives of NIR-II optical imaging probes will also be discussed.

Flexible liposomal gel dual-loaded with all-trans retinoic acid and betamethasone for enhanced therapeutic efficiency of psoriasis.

BACKGROUND: Psoriasis is a chronic immune-mediated inflammatory skin disease without effective treatment. The utilization of all trans-retinoic acid (TRA) and betamethasone (BT) for the treatment of psoriasis is still facing difficulties, due to their relatively poor stability, limited skin permeation, and systemic side effects. Flexible liposomes are excellent in deeper skin permeation and reducing the side effects of drugs, which is promising for effective treatment of skin disorders. This work aimed to establish dual-loaded flexible liposomal gel for enhanced therapeutic efficiency of psoriasis based on TRA and BT. RESULTS: Flexible liposomes co-loaded with TRA and BT were successfully prepared in our study. The characterization examination revealed that flexible liposomes featured nano-sized particles (around 70 nm), high drug encapsulation efficiency (> 98%) and sustained drug release behaviors. Flexible liposomes remarkably increased the drug skin permeation and retention as compared with free drugs. Results on HaCaT cells suggested that flexible liposomes were nontoxic, and its cellular uptake has a time-dependent manner. In vivo studies suggested the topical application of TRA and BT dual-loaded liposomal gel had the best ability to reduce the thickness of epidermal and the level of cytokines (TNF-α and IL-6), largely alleviating the symptoms of psoriasis. CONCLUSIONS: Flexible liposomal gel dual-loaded with TRA and BT exerted a synergistic effect, which is a promising topical therapeutic for the treatment of psoriasis.

Polysialic-Acid-Based Micelles Promote Neural Regeneration in Spinal Cord Injury Therapy.

Spinal cord injury (SCI) routinely causes the immediate loss and disruption of neurons followed by complicated secondary injuries, including inflammation, oxidative stress, and dense glial scar formation. Inhibitory factors in the lesion scar and poor intrinsic neural regeneration capacity restrict functional recovery after injury. Minocycline, which has neuroprotective activity, can alleviate secondary injury, but the long-term administration of this drug may cause toxicity. Polysialic acid (PSA) is a large cell-surface carbohydrate that is critical for central nervous system development and is capable of promoting precursor cell migration, axon path finding, and synaptic remodeling; thus, PSA plays a vital role in tissue repair and regeneration. Here, we developed a PSA-based minocycline-loaded nanodrug delivery system (PSM) for the synergistic therapy of spinal cord injury. The prepared PSM exerted marked anti-inflammatory and neuroprotective activities both in vitro and in vivo. The administration of PSM could significantly protect neurons and myelin sheaths from damage, reduce the formation of glial scar, recruit endogenous neural stem cells to the lesion site, and promote the regeneration of neurons and the extension of long axons throughout the glial scar, thereby largely improving the locomotor function of SCI rats and exerting a superior therapeutic effect. The findings might provide a novel strategy for SCI synergistic therapy and the utilization of PSA in other central nervous system diseases.

Highly Integrated Nanoplatform Based on an E-Selectin-Targeting Strategy for Metastatic Breast Cancer Treatment.

Therapeutic goals for metastatic breast cancer, including shrinkage of established metastasis and suppression of movement of tumor cells, are often hard to achieve and remain the main obstacles restricting the antimetastatic efficacy of targeted drug delivery systems (TDDSs). Herein, we proposed an E-selectin-targeting nanoplatform for the systemic treatment of metastatic breast cancer. Versatile functions, including killing the circulating tumor cells, shrinking the established lesions, as well as inhibiting the movement of tumor cells, were integrated into doxorubicin-loaded sialic acid-dextran-octadecanoic acid (SDO) micelles (SDD). The prepared SDD micelles could not only inhibit lung and liver metastasis in the orthotopic 4T1 tumors model, but also decrease the metastatic lesions in the metastatic 4T1 cell model, resulting in 27.33% reduced number of metastatic nodules when compared to those without sialic acid modification. It was found that the good antimetastatic effect of SDD was only partially attributed to its ability on removing metastatic cells and metastases. Most importantly, the blank SDO micelles left in the lesion could further inhibit the cell migration and cell-cell binding. These results suggest that SA-driven TDDS has the potential for specific targeting and effective treatment of cancer metastasis.

Potentiated Calcium Carbonate with Enhanced Calcium Overload Induction and Acid Neutralization Capabilities to Boost Chemoimmunotherapy against Liver Cancer.

Unfavorable phenotypes characterized by low immunogenicity and acidity within the tumor microenvironment (TME) contribute to immunosuppression and therapeutic resistance. Herein, we rationally synthesized a multifunctional nanoregulator by encapsulating DOX and erianin into calcium carbonate (CaCO3)-based nanoparticles using a modified double emulsion method. The DOX and erianin-loaded CaCO3-based nanoparticles, termed DECaNPs, could effectively induce the calcium overload by triggering calcium influx and absorbing CaCO3 nanoparticles. Additionally, DECaNPs also neutralize the acidic TME by interacting with extracellular protons and limiting lactic acid production, a result of metabolic remodeling in cancer cells. As a result, DECaNPs elicit cellular oxidative stress damage, which mediates the activation of ferroptosis/apoptosis hybrid pathways, and profound immunogenic cell death. Treatment with DECaNPs could inhibit the growth of tumors by promoting oxidative stress, acid neutralization, metabolic remodeling, and protective antitumor immunity in vivo. In addition, DECaNPs could synergistically amplify the antitumor effects of αPD-L1 in a bilateral tumor model by eliciting systemic immune responses. In all, our work presents the preparation of CaCO3-based nanoregulators designed to reverse the unfavorable TME and enhance αPD-L1 immunotherapy through multiple mechanisms.

Multiple Immunomodulatory Strategies Based on Targeted Regulation of Proprotein Convertase Subtilisin/Kexin Type 9 and Immune Homeostasis against Hepatocellular Carcinoma.

Immunotherapy is the most promising systemic therapy for hepatocellular carcinoma. However, the outcome remains poor. Proprotein convertase subtilisin/kexin type 9 (PCSK9) plays a role in altering cell-surface protein levels, potentially undermining the efficacy of immunotherapy against tumors. This highlights its potential as a target for antitumor therapy. Herein, CaCO3-based nanoparticles coencapsulated with DOX, an immunogenic cell death (ICD) inducer, and evolocumab was developed to enhanced the efficacy of immunotherapy. The obtained DOX/evolocumab-loaded CaCO3 nanoparticle (named DECP) exhibits a good capacity of acid neutralization and causes ICD of cancer cells. In addition, DECP is able to evaluate the cell-surface level of MHC-I, a biomarker that correlates positively with patients' overall survival. Upon intravenous injection, DECP accumulates within the tumor site, leading to growth inhibition of hepa1-6 bearing subcutaneous tumors. Specifically, DECP treatment causes augmented ratios of matured dendritic cells, tumor-infiltrating CD8+ T cells and natural killing cells, while concurrently depleting Foxp3+ regulatory T cells. Peritumoral delivery of DECP enhances the immune response of distant tumors and exhibits antitumor effects when combined with intravenous αPD-L1 therapy in a bilateral tumor model. This study presents CaCO3-based nanoparticles with multiple immunomodulatory strategies against hepatocellular carcinoma by targeting PCSK9 inhibition and modulating immune homeostasis in the unfavorable TME.

Mesenchymal stem cell-derived extracellular vesicles in skin wound healing: roles, opportunities and challenges.

Skin wounds are characterized by injury to the skin due to trauma, tearing, cuts, or contusions. As such injuries are common to all human groups, they may at times represent a serious socioeconomic burden. Currently, increasing numbers of studies have focused on the role of mesenchymal stem cell (MSC)-derived extracellular vesicles (EVs) in skin wound repair. As a cell-free therapy, MSC-derived EVs have shown significant application potential in the field of wound repair as a more stable and safer option than conventional cell therapy. Treatment based on MSC-derived EVs can significantly promote the repair of damaged substructures, including the regeneration of vessels, nerves, and hair follicles. In addition, MSC-derived EVs can inhibit scar formation by affecting angiogenesis-related and antifibrotic pathways in promoting macrophage polarization, wound angiogenesis, cell proliferation, and cell migration, and by inhibiting excessive extracellular matrix production. Additionally, these structures can serve as a scaffold for components used in wound repair, and they can be developed into bioengineered EVs to support trauma repair. Through the formulation of standardized culture, isolation, purification, and drug delivery strategies, exploration of the detailed mechanism of EVs will allow them to be used as clinical treatments for wound repair. In conclusion, MSC-derived EVs-based therapies have important application prospects in wound repair. Here we provide a comprehensive overview of their current status, application potential, and associated drawbacks.

A Luminol-Based Self-Illuminating Nanocage as a Reactive Oxygen Species Amplifier to Enhance Deep Tumor Penetration and Synergistic Therapy.

The dense extracellular matrix (ECM) in tumor tissues resists drug diffusion into tumors and leads to a poor prognosis. To address this problem, glucose oxidase (GOx)-modified ferritin loaded with luminol-curcumin was fabricated. Once delivered to the tumor, this luminol-based self-illuminating nanocage could actively convert glucose to reactive oxygen species (ROS) to achieve starvation therapy. Then, excessive ROS were transmitted to luminol, thereby emitting 425 nm blue-violet light. Momentarily, light was further absorbed by curcumin and ROS production was amplified. Abundant ROS helps break down the ECM network to penetrate deep into tumors. In addition, ROS produced after cell internalization can induce apoptosis of tumor cells by decreasing the mitochondrial membrane potential and can promote ferroptosis by consuming reduced glutathione. Effective penetration and multiple pathways inducing tumor cell death contributed to the efficient antitumor effect (tumor inhibition rate of GOx-modified ferritin loaded with luminol-curcumin: 71.73%). This study developed a glucose-driven self-illuminating nanocage for active tumor penetration via ROS-mediated destruction of the ECM and provided the synergetic mechanism of apoptosis and ferroptosis.

Percutaneous biliary stent combined with brachytherapy using 125I seeds for treatment of unresectable malignant obstructive jaundice: A meta-analysis.

BACKGROUND: Malignant obstructive jaundice (MOJ) is a common pathologic manifestation of malignant biliary obstruction. Recently, several clinical trials have explored the clinical effectiveness of intraluminal 125I seed-based brachytherapy for MOJ patients, and various outcomes have been reported. AIM: To assess the efficacy and safety of percutaneous biliary stents with 125I seeds compared to conventional metal stents in patients with unresectable MOJ. METHODS: A systematic search of English-language databases (PubMed, Embase, Cochrane Library, and Web of Science) was performed to identify studies published prior to June 2020 that compared stents with or without 125I seeds in the treatment of unresectable MOJ. The outcomes analyzed included primary outcomes (stent patency and overall survival) and secondary outcomes (complications and liver function parameters). RESULTS: Six randomized controlled trials and four retrospective studies involving 875 patients were eligible for the analysis. Of the 875 included patients, 404 were treated with 125I seed stents, while 471 were treated with conventional stents. Unadjusted pooled analysis demonstrated that compared to conventional stents, 125I seed stents extended the stent patency time [hazard ratio (HR) = 0.36, 95% confidence interval (CI) = 0.28-0.45, P < 0.0001] and overall survival period (HR = 0.52, 95%CI = 0.42-0.64, P < 0.00001). Subgroup analyses based on the type of 125I seed stent and type of study design showed consistent results. However, there were no significant differences in the occurrence of total complications [odds ratio (OR) = 1.12, 95%CI = 0.75-1.67, P = 0.57], hemobilia (OR = 1.02, 95%CI = 0.45-2.3, P = 0.96), pancreatitis (OR = 1.79, 95%CI = 0.42-7.53, P = 0.43), cholangitis (OR = 1.13, 95%CI = 0.60-2.13, P = 0.71), or pain (OR = 0.67, 95%CI = 0.22-2, P = 0.47). In addition, there were no reductions in the levels of serum indices, including total bilirubin [mean difference (MD) = 10.96, 95%CI = -3.56-25.49, P = 0.14], direct bilirubin (MD = 7.37, 95%CI = -9.76-24.5, P = 0.4), alanine aminotransferase (MD = 7.52, 95%CI = -0.71-15.74, P = 0.07), and aspartate aminotransferase (MD = -4.77, 95%CI = -19.98-10.44, P = 0.54), after treatment. Publication bias was detected regarding the outcome overall survival; however, the conclusions were not changed after the adjustment. CONCLUSION: Placement of stents combined with brachytherapy using 125I seeds contributes to a longer stent patency and higher overall survival than placement of conventional stents without extra complications or severe liver damage. Thus, it can be considered an effective and safe treatment for unresectable MOJ.

Sialic acid-modified chitosan oligosaccharide-based biphasic calcium phosphate promote synergetic bone formation in rheumatoid arthritis therapy.

Therapeutic goals for rheumatoid arthritis (RA) consist of inhibiting the inflammatory response and repairing the damaged bone/cartilage. Tissue engineering could achieve both goals, however, it was hindered due to the lack of biologically relevant tissue complexity, limitation in covering the entire polyarthritis lesions and requirement of extra surgical implantation. Integrating nanotechnologies into clinically sized implants represents a major opportunity to overcome these problems. Herein, we designed a sialic acid (SA)-modified chitosan oligosaccharide-based biphasic calcium phosphate (BCP), a biomimetic nanoplatform that could load with methotrexate. We found that SA modification could not only improve the accumulation of the designed organic-inorganic nanoplatform in arthritic paws (34.38% higher than those without SA modification at 48 h), but also cooperate with BCP to exert synergetic mineralization of calcium phosphate, allowing more osteoblasts to attach, proliferate and differentiate. The more differentiated osteoblasts produced 4.46-fold type I collagen and 2.60-fold osteoprotegerin compared to the control group. Besides, the disassembled nanorods released chitosan oligosaccharide-based micelles, revealing a cartilage-protective effect by reducing the loss of glycosaminoglycan. All these improvements contributed to the light inflammatory response and reduced destruction on cartilage/bone. The findings provide a novel strategy for RA therapy via nanometer-scale dimension mimicking the natural tissues.

Gadolinium-loaded calcium phosphate nanoparticles for magnetic resonance imaging of orthotopic hepatocarcinoma and primary hepatocellular carcinoma.

The development of magnetic resonance imaging (MRI) contrast agents with high sensitivity and good biocompatibility is of great value for the diagnosis of primary hepatocellular carcinoma (HCC). Here, a novel MRI contrast agent based on calcium phosphate (CaP) nanoparticles modified with a liver cancer cell targeting peptide A54 (A54-CaP) was fabricated. The T1-positive contrast agent Gd-DTPA was encapsulated inside the nanoparticles (A54-CaPNPs), with a mean diameter of 30 nm and a high encapsulation efficiency of 92.73%. The A54-CaPNP solution exhibited higher longitudinal relaxivity (6.07 mM-1 s-1) than that of the clinically used MRI contrast agent Gd-DTPA (3.56 mM-1 s-1). A much higher accumulation of the nanoparticles in the liver cells was observed, which was directed by the A54 targeting peptide. Furthermore, the MRI diagnostic efficiency of A54-CaPNPs was systematically investigated in an orthotopic liver cancer model and primary HCC model. In vivo MRI experiments showed that A54-CaPNPs had higher sensitivity in the BEL-7402 orthotopic liver cancer model with a more remarkable contrast enhancement and a longer imaging time compared to those without A54 modification. Moreover, the experiments on primary HCC models suggested that A54-CaPNPs showed greatly enhanced MR imaging performance in comparison with Gd-DTPA. These results suggest that A54-CaPNPs possess great potential to enable the non-invasive early diagnosis of primary HCC for timely surgical resection.

Effective targeted therapy for drug-resistant infection by ICAM-1 antibody-conjugated TPGS modified ß-Ga2O3:Cr3+ nanoparticles.

The prevalence of antibiotic resistance and lack of alternative drugs have posed an increasing threat to public health. Here, we prepared ß-Ga2O3:Cr3+ nanoparticles modified with ICAM1-antibody-conjugated TPGS (I-TPGS/Ga2O3) as a novel antibiotic carrier for the treatment of drug-resistant infections. Methods: I-TPGS/Ga2O3 were firstly characterized by measuring particle size, morphology, crystal structure, drug loading capacity, and in vitro drug release behaviors. The in vitro antibacterial activities of I-TPGS/Ga2O3/TIG were evaluated using standard and drug-resistant bacteria. The internalization of I-TPGS/Ga2O3 was observed by fluorescence confocal imaging, and the expression levels of the efflux pump genes of TRKP were analyzed by real-time RT-PCR. In vitro cellular uptake and in vivo biodistribution study were performed to investigate the targeting specificity of I-TPGS/Ga2O3 using HUEVC and acute pneumonia mice, respectively. The in vivo anti-infective efficacy and biosafety of I-TPGS/Ga2O3/TIG were finally evaluated using acute pneumonia mice. Results: It was found that TPGS could down-regulate the over-expression of the efflux pump genes, thus decreasing the efflux pump activity of bacteria. I-TPGS/Ga2O3 with small particle size and uniform distribution facilitated their internalization in bacteria, and the TPGS modification resulted in a significant reduction in the efflux of loaded antibiotics. These properties rendered the encapsulated tigecycline to exert a stronger antibacterial activity both in vitro and in vivo. Additionally, targeted delivery of I-TPGS/Ga2O3 mediated by ICAM1 antibodies contributed to a safe and effective therapy. Conclusion: It is of great value to apply I-TPGS/Ga2O3 as a novel and effective antibiotic delivery system for the treatment of drug-resistant infections.

Combinational protective therapy for spinal cord injury medicated by sialic acid-driven and polyethylene glycol based micelles.

Spinal cord injury (SCI) leads to immediate disruption of neuronal membranes and loss of neurons, followed by extensive secondary injury process. Treatment of SCI still remains a tremendous challenge clinically. Minocycline could target comprehensive secondary injury via anti-inflammatory, anti-oxidant and anti-apoptotic mechanisms. Polyethylene glycol (PEG), a known sealing agent, is able to seal the damaged cell membranes and reduce calcium influx, thereby exerting neuroprotective capacity. Here, an E-selectin-targeting sialic acid - polyethylene glycol - poly (lactic-co-glycolic acid) (SAPP) copolymer was designed for delivering hydrophobic minocycline to achieve combinational therapy of SCI. The obtained SAPP copolymer could self-assemble into micelles with critical micelle concentration being of 13.40 µg/mL, and effectively encapsulate hydrophobic minocycline. The prepared drug-loaded micelles (SAPPM) displayed sustained drug release over 72 h, which could stop microglia activation and exhibited excellent neuroprotective capacity in vitro. The SAPP micelles were efficiently accumulated in the lesion site of SCI rats via the specific binding between sialic acid and E-selectin. Due to the targeting distribution and combinational effect between PEG and minocycline, SAPPM could obviously reduce the area of lesion cavity, and realize more survival of axons and myelin sheaths from the injury, thus distinctly improving hindlimb functional recovery of SCI rats and conferring superior therapeutic effect in coparison with other groups. Our work presented an effective and safe strategy for SCI targeting therapy. Besides, neuroprotective capacity of PEG deserves further investigation on other central nervous system diseases.