Efficacy of melanin-loaded lipoic acid-modified chitosan hydrogel in diabetic wound healing.

The healing of diabetic wounds is significantly impeded due to severe oxidative stress and hindered angiogenesis, presenting a major challenge to clinical treatment. In this context, we introduces a novel hydrogel dressing strategy that uniquely combines α-lipoic acid-modified chitosan (LAMC) and melanin nanoparticles (MNPs). This innovative hydrogel, LAMC@MNPs, is formulated to gel under ultraviolet (UV) light without the need for a photoinitiator, simplifying the preparation process and potentially enhancing safety. Our experimental results demonstrate that the LAMC@MNPs hydrogel not only exhibits superior skin adhesion, with an average strength of 56.59 ± 3.16 KPa, but also effectively alleviates oxidative stress and accelerates vascular regeneration and wound healing. This is achieved by promoting cell migration and scavenging free radicals, addressing the critical barriers in diabetic wound care. The combination of these materials and their functional benefits presents a promising new approach to diabetic wound treatment.

Incorporation of Finasteride-Loaded Microspheres into Personalized Microneedle for Sustained Transdermal Delivery.

Although finasteride (FNS) tablets are considered the most effective drug for the treatment of androgenetic alopecia (AGA), their clinical applications are limited due to the associated side effects including decreased libido, breast enlargement, and liver dysfunction. In this study, we have developed a personalized microneedle (PMN) with a double-layer structure that incorporates FNS-loaded microspheres (MPs) to accommodate irregular skin surfaces. This design enables the sustained release of FNS, thereby reducing potential side effects. The needle body was synthesized with high-strength hyaluronic acid (HA) as the base material substrate. The backing layer utilized methacrylate gelatin (GelMA) with specific toughness, enabling PMN to penetrate the skin while adapting to various skin environments. The length of PMN needles (10 × 10) was approximately 600 µm, with the bottom of the needles measuring about 330 µm × 330 µm. The distance between adjacent tips was around 600 µm, allowing the drug to penetrate the stratum corneum of the skin. The results of the drug release investigation indicated the sustained and regulated release of FNS from PMN, as compared to that of pure FNS and FNS-MPs. Further, the cytotoxicity assay demonstrates that PMS displays good cytocompatibility. Altogether, this mode of administration has immense potential for the development of delivery of other drugs, as well as in the medical field.

From Hit to Lead: Structure-Based Optimization of Novel Selective Inhibitors of Receptor-Interacting Protein Kinase 1 (RIPK1) for the Treatment of Inflammatory Diseases.

Receptor-interacting protein kinase 1 (RIPK1) is a key regulator of cellular necroptosis, which is considered as an important therapeutic target for necroptosis-related indications. Herein, we report the structural optimization and structure-activity relationship investigations of a series of eutectic 5-substituted-indole-3-carboxamide derivatives. The prioritized compound 10b exhibited low nanomolar IC50 values against RIPK1 and showed good kinase selectivity. Based on its eutectic structure, 10b occupied both the allosteric and ATP binding pockets of RIPK1, making it a potent dual-mode inhibitor of RIPK1. In vitro, 10b had a potent protective effect against necroptosis in cells. Compound 10b also provided robust protection in a TNFα-induced systemic inflammatory response syndrome (SIRS) model and imiquimod (IMQ)-induced psoriasis model. It also showed good pharmacokinetic properties and low toxicity. Overall, 10b is a promising lead compound for drug discovery targeting RIPK1 and warrants further study.

Anticancer and bone-enhanced nano-hydroxyapatite/gelatin/polylactic acid fibrous membrane with dual drug delivery and sequential release for osteosarcoma.

Surgical resection of osteosarcoma is always accompanied by residual metastasis of tumor cells and bone tissue defects. In this work, a novel kind of gelatin/polylactic acid (PLA) coaxial fiber membrane with a shell layer containing doxorubicin-loaded hydroxyapatite (DOX@nHAp) nanoparticles and a core layer containing Icariin (ICA) was developed for antitumor and bone enhancement at the defect site. Physical evaluation displayed that the composite membrane provided moderate hydrophilicity, enhanced tensile strength (Dry: 2-3 MPa, wet: 1-2 MPa) and elasticity (70-100 %), as well as increased specific surface area and pore volume (19.39 m2/g and 0.16 cm3/g). In SBF, DOX@nHAp in the fibers promoted biomineralization on the fiber surface. In in vitro evaluation, approximately 80 % of DOX had a short-term release during the first 8 days, followed by long-term release behavior of ICA for up to 40 days. CCK-8 results confirmed that the membrane could actively support MC3T3-E1 cells proliferation and was conductive to high alkaline phosphatase expression, while the viability of MG-63 cells was effectively inhibited to 50 %. Thus, the dual-loaded fibrous membrane with a coaxial structure and nHAp is a promising system for anticancer and defects reconstruction after osteosarcoma surgery.

Poly(ß-amino ester) Dual-Drug-Loaded Hydrogels with Antibacterial and Osteogenic Properties for Bone Repair.

In this study, we developed a poly(ß-amino ester) (PBAE) hydrogel for the double release of vancomycin (VAN) and total flavonoids of Rhizoma Drynariae (TFRD). VAN was covalently bonded to PBAE polymer chains and was released to enhance the antimicrobial effect first. TFRD chitosan (CS) microspheres were physically dispersed in the scaffold, TFRD was released from the microspheres, and osteogenesis was induced subsequently. The scaffold had good porosity (90.12 ± 3.27%), and the cumulative release rate of the two drugs in PBS (pH 7.4) solution exceeded 80%. In vitro antimicrobial assays demonstrated the antibacterial properties of the scaffold against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). Besides these, cell viability assays indicated that the scaffold had good biocompatibility. Moreover, alkaline phosphatase and matrix mineralization were expressed more than in the control group. Overall, cell experiments confirmed that the scaffolds have enhanced osteogenic differentiation capabilities. In conclusion, the dual-drug-loaded scaffold with antibacterial and bone regeneration effects is promising in the field of bone repair.

A new generation Mpro inhibitor with potent activity against SARS-CoV-2 Omicron variants.

Emerging SARS-CoV-2 variants, particularly the Omicron variant and its sublineages, continually threaten the global public health. Small molecule antivirals are an effective treatment strategy to fight against the virus. However, the first-generation antivirals either show limited clinical efficacy and/or have some defects in pharmacokinetic (PK) properties. Moreover, with increased use of these drugs across the globe, they face great pressure of drug resistance. We herein present the discovery and characterization of a new generation antiviral drug candidate (SY110), which is a potent and selective inhibitor of SARS-CoV-2 main protease (Mpro). This compound displayed potent in vitro antiviral activity against not only the predominant SARS-CoV-2 Omicron sublineage BA.5, but also other highly pathogenic human coronaviruses including SARS-CoV-1 and MERS-CoV. In the Omicron-infected K18-hACE2 mouse model, oral treatment with SY110 significantly lowered the viral burdens in lung and alleviated the virus-induced pathology. Importantly, SY110 possesses favorable PK properties with high oral drug exposure and oral bioavailability, and also an outstanding safety profile. Furthermore, SY110 exhibited sensitivity to several drug-resistance Mpro mutations. Collectively, this investigation provides a promising new drug candidate against Omicron and other variants of SARS-CoV-2.

Generative deep learning enables the discovery of a potent and selective RIPK1 inhibitor.

The retrieval of hit/lead compounds with novel scaffolds during early drug development is an important but challenging task. Various generative models have been proposed to create drug-like molecules. However, the capacity of these generative models to design wet-lab-validated and target-specific molecules with novel scaffolds has hardly been verified. We herein propose a generative deep learning (GDL) model, a distribution-learning conditional recurrent neural network (cRNN), to generate tailor-made virtual compound libraries for given biological targets. The GDL model is then applied to RIPK1. Virtual screening against the generated tailor-made compound library and subsequent bioactivity evaluation lead to the discovery of a potent and selective RIPK1 inhibitor with a previously unreported scaffold, RI-962. This compound displays potent in vitro activity in protecting cells from necroptosis, and good in vivo efficacy in two inflammatory models. Collectively, the findings prove the capacity of our GDL model in generating hit/lead compounds with unreported scaffolds, highlighting a great potential of deep learning in drug discovery.

Correction: Preparation and characterization of a novel drug-loaded Bi-layer scaffold for cartilage regeneration.

[This corrects the article DOI: 10.1039/D2RA00311B.].

Preparation and characterization of a novel drug-loaded Bi-layer scaffold for cartilage regeneration.

The incidence of articular cartilage defects is increasing year by year. In order to repair the cartilage tissue at the defect, scaffolds with nanofiber structure and biocompatibility have become a research hotspot. In this study, we designed and fabricated a bi-layer scaffold prepared from an upper layer of drug-dispersed gelatin methacrylate (GELMA) hydrogel and a lower layer of a drug-encapsulated coaxial fiber scaffold prepared from silk fiber (SF) and polylactic acid (PLA). These bi-layer scaffolds have porosity (91.26 ± 3.94%) sufficient to support material exchange and pore size suitable for cell culture and infiltration, as well as mechanical properties (2.65 ± 0.31 MPa) that meet the requirements of cartilage tissue engineering. The coaxial fiber structure exhibited excellent drug release properties, maintaining drug release for 14 days in PBS. In vitro experiments indicated that the scaffolds were not toxic to cells and were amenable to chondrocyte migration. Notably, the growth of cells in a bi-layer scaffold presented two states. In the hydrogel layer, cells grow through interconnected pores and take on a connective tissue-like shape. In the coaxial fiber layer, cells grow on the surface of the coaxial fiber mats and appeared tablet-like. This is similar to the structure of the functional partitions of natural cartilage tissue. Together, the bi-layer scaffold can play a positive role in cartilage regeneration, which could be a potential therapeutic choice to solve the current problems of clinical cartilage repair.

PDLLA/ß-TCP/HA/CHS/NGF Sustained-release Conduits for Peripheral Nerve Regeneration.

Using nerve guide conduits (NGCs) to promote the regeneration of PNI is a feasible alternative to autograft. Compared with NGCs made of single material, composite NGCs have a greater development prospect. Our previous research has confirmed that poly(D, L-lactic acid)/ß-tricalcium phosphate/hyaluronic acid/chitosan/nerve growth factor (PDLLA/ß-TCP/HA/CHS/NGF) NGCs have excellent physical and chemical properties, which can slowly release NGF and support cell adhesion and proliferation. In this study, PDLLA/ß-TCP/HA/CHS/NGF NGCs were prepared and used to bridge a 10 mm sciatic nerve defect in 200-250 g Sprague-Dawley (SD) rat to verify the performance of the NGCs in vivo. Substantial improvements in nerve regeneration were observed after using the PDLLA/ß-TCP/HA/CHS/NGF NGCs based on gross post-operation observation, triceps wet weight analysis and nerve histological assessment. In vivo studies illustrate that the PDLLA/ß-TCP/HA/CHS/NGF sustained-release NGCs can effectively promote peripheral nerve regeneration, and the effect is similar to that of autograft.

PEGylated Nanoscale Metal-Organic Frameworks for Targeted Cancer Imaging and Drug Delivery.

Nanoscale metal-organic frameworks (nMOFs) are a unique type of hybrid materials, which are broadly applicable as cargo delivery systems. However, the relatively low material stability and insufficient cancer cell interacting capacity have limited nMOFs' applications in cancer theranostics. Herein, a zirconium-based nMOF UiO-66-N3 was synthesized, and its surface was covalently functionalized with alkyne-containing polyethylene glycol (PEG) via the azide-alkyne click chemistry. After that, F3 peptide was attached for targeting of cancer cells (the material was denoted as UiO-66-PEG-F3). Doxorubicin (DOX) served as a therapeutic drug and a fluorescent label in this study, and it was transported into UiO-66-PEG conjugates with sufficient drug loading efficiency. pH-responsive release of DOX from UiO-66 conjugates was witnessed. The structural integrity of UiO-66-N3 was maintained post the surface modification process. Flow cytometry and confocal fluorescence microscopy revealed that DOX/UiO-66-PEG-F3 had stronger accumulation in MDA-MB-231 cells (nucleolin+) compared with DOX/UiO-66-PEG. In order to track the pharmacokinetic behavior (organ distribution profile) in vivo, the positron-emitting zirconium-89 (89Zr) was incorporated into UiO-66-N3. Similar PEGylation and F3 peptide conjugation resulted in the formation of 89Zr-UiO-66-PEG-F3. Serial positron emission tomography (PET) imaging demonstrated that the preferential accumulation of 89Zr-UiO-66-PEG-F3 in MDA-MB-231 tumors, and their liver clearance was faster than PEGylated UiO-66 using noncovalent methods. Thus, the PEGylated nMOFs using covalent strategies may find broad application in future cancer theranostics.

Insights into the degradation mechanisms and pathways of cephalexin during homogeneous and heterogeneous photo-Fenton processes.

The widespread occurrence of antibiotics in the environment poses a potential threat to human health. The photo-Fenton process has demonstrated better degradation performance compared with the conventional wastewater treatment processes. In this study, the degradation of cephalexin was evaluated comparatively by homogeneous (Fe2+/H2O2/UV) and heterogeneous (MoS2@Fe/H2O2/UV) photo-Fenton processes. Key influencing factors affecting photo-Fenton performance were assessed, confirming the optimum Fe2+ concentration at 0.2016 mg L-1 and H2O2/Fe2+ molar ratio at 6. Higher degradation efficiency (73.10%) and pseudo-first-order degradation rate constant (0.0078 min-1) were achieved with the assistance of MoS2@Fe as the heterogeneous catalyst. Completely different degradation products were identified in the homogeneous and heterogeneous photo-Fenton processes, with main degradation pathways proposed as ß-lactam ring-opening, sulfoxide formation, demethylation, N-dealkylation, decarbonylation, hydroxylation and deamination in the Fe2+/H2O2/UV system and ß-lactam ring-opening, hydroxylation, dehydration, amide hydrolysis, and demethylation and ring contraction in the MoS2@Fe/H2O2/UV system, respectively. The formation of newly identified products might root in the attack on cephalexin from active species (i.e., OH, h+, e-, O2-) photoinduced by the MoS2@Fe catalyst. Results also indicated the importance of understanding the underlying mechanisms and pathways to eliminate the antimicrobial activities of antibiotics in the future.

Development of a nanobody-based immunoassay for the sensitive detection of fibrinogen-like protein 1.

Immune checkpoint inhibition is an important strategy in cancer therapy. Blockade of CTLA-4 and PD-1/PD-L1 is well developed in clinical practice. In the last few years, LAG-3 has received much interest as an emerging novel target in immunotherapy. It was recently reported that FGL1 is a major ligand of LAG-3, which is normally secreted by the liver but is upregulated in several human cancers. FGL1 is a crucial biomarker and target for cancer immunotherapy. As the efficacy of immunotherapy is limited to specific types of patients, the subset of patients needs to be selected appropriately to receive precise treatment according to different biomarkers. To date, there is no test to accurately assess FGL1 expression levels. Nanobodies have some outstanding features, such as high stability, solubility and affinity for diagnostic and therapeutic applications. Here, we report the development and validation of a rapid, sensitive, and cost-effective nanobody-based immunoassay for the detection of FGL1 in human serum. In this study, human FGL1 recombinant protein was expressed and purified for the first time as an immunized antigen. Then, we constructed a nanobody phage display library and screened several nanobodies that bind FGL1 with high affinity. We selected two nanobodies targeting different epitopes of FGL1, one as a capture and the other conjugated with HRP as a probe. The double nanobody-based sandwich ELISA to detect the concentration of FGL1 showed a good response relationship in the range of 15.625-2000 ng/mL, and the recoveries from the spiked sample were in the range of 78% and 100%. This assay could be used as a potential approach for evaluating FGL1 expression for patient stratification and for predicting the therapeutic efficacy of targeting the LAG3/FGL1 axis.

Pentapeptide IKVAV-engineered hydrogels for neural stem cell attachment.

Spinal cord injury remains irreversible with current treatment paradigms, due to the inability to rebuild the regenerative environment for neurons after injury. Neural tissue engineering that encapsulates the neural stem/progenitor cells within an artificial scaffold provides a possibility to regenerate neurons for spinal cord injury repair. The attachment and survival of these neural cells usually require similar microenvironments to the extracellular matrix for support. Here, a three-dimensional pentapeptide IKVAV-functionalized poly(lactide ethylene oxide fumarate) (PLEOF) hydrogel is developed. In vitro tests demonstrate that the IKVAV-PLEOF hydrogels are biodegradable and hemo-biocompatible. This IKVAV-PLEOF hydrogel is shown to support neural stem cell attachment, growth, proliferation, and differentiation. Additionally, the neural stem cells could be readily formed as spheroids that subsequently encapsulated, attached, and proliferated within the three-dimensional hydrogel constructs. Additionally, an in vivo test confirms the biodegradability and biocompatibility of the IKVAV-PLEOF hydrogels revealing that the hydrogels biodegrade, new blood vessels form, and few inflammatory responses are observed after 4-week implantation. The neural stem cell spheroid-laden hydrogels may have further implications in spinal cord injury regenerative and brain repair in neural tissue engineering.

Hyaluronic acid targeted and pH-responsive nanocarriers based on hollow mesoporous silica nanoparticles for chemo-photodynamic combination therapy.

In this work, a pH-responsive and tumor targeted multifunctional drug delivery system (RB-DOX@HMSNs-N = C-HA) was designed to realize chemo-photodynamic combination therapy. Hollow mesoporous silica nanoparticles (HMSNs) was served as the host material to encapsulate doxorubicin (DOX) and photosensitizer rose bengal (RB). Hyaluronic acid (HA) was modified on the surface of HMSNs via pH-sensitive Schiff base bonds as gatekeeper as well as targeted agent. Characterization results indicated the successful preparation of HMSNs-N = C-HA with appropriate diameter of 170 nm around and the nanocarriers displayed superior drug loading capacity (15.30 % for DOX and 12.78 % for RB). Notably, the results of in vitro drug release experiments confirmed that the system possessed good pH-sensitivity, which made it possible to release cargoes in slight acid tumor micro-environments. Significantly, the in vitro cell uptake and cytotoxicity assay results fully proved that RB-DOX@HMSNs-N = C-HA could precisely target murine mammary carcinoma (4T1) cells and effectively inhibit tumor cells viability with chemo-photodynamic synergistic therapy. Overall, our work (RB-DOX@HMSNs-N = C-HA) provides an efficient approach for the development of chemo-photodynamic combination therapy.

The electrostimulation and scar inhibition effect of chitosan/oxidized hydroxyethyl cellulose/reduced graphene oxide/asiaticoside liposome based hydrogel on peripheral nerve regeneration in vitro.

The application of hollow nerve conduits in the repair of peripheral nerve defects is effected by inferior recovery, and nerve extension is hampered by the scar tissue generated during the repair process. In this study, the filler in hollow nerve conduit, chitosan/oxidized hydroxyethyl cellulose (CS/OHEC) hydrogel loaded asiaticoside liposome and the conductive reduced graphene oxide (rGO) were developed and used to reform the microenvironment for peripheral nerve regeneration. The physiochemical properties of CS/OHEC/rGO/asiaticoside liposome hydrogel were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and compressive modulus, porosity, swelling ratio, degradation and conductivity. In addition, the asiaticoside release profiles in vitro were investigated. The hydrogel had a continuous porous network structure with pore size distribution in the range of 50-250 µm. The majority of the hydrogels had porosities above 70%, and a compressive modulus of 0.45 MPa. The weight loss rate of hydrogel reached 76.14 ± 4.45% within 8 weeks. The conductivity of the hydrogel was 5.27 ± 0.42 × 10-4 S/cm. The hydrogel was non-toxic and suitable for adhesion and proliferation of nerve cells in vitro. In addition, the application of electrical stimulation after the addition of rGO can promote the differentiation and proliferation of nerve cells, accelerating nerve regeneration. The asiaticoside released from the hydrogel had a significant inhibitory effect on the growth and collagen secretion of fibroblasts, eliminating scars for regenerative nerves, which can promote the function recovery of defected peripheral nerve. Together, these positive results indicate that the hydrogel would be a promising candidate for peripheral nerve regeneration.

Optimal route of gold nanoclusters administration in mice targeting Parkinson's disease.

Aim: To explore the optimal route of gold nanoclusters (AuNCs) administration in mice targeting Parkinson's disease. Materials & methods: Assessing the pharmacokinetic and bioavailability of AuNCs in mice administrated following intravenous, intraperitoneal, gavage and intranasal injection. Investigating the biodistribution of AuNCs in mice by atomic absorption spectrometry and transmission electron microscope. Toxicity assessments of AuNCs were carried out both in cells and in mice. Results: Administration of AuNCs via intraperitoneal injection showed the greatest bioavailability and the longest residence in brain. AuNCs could penetrate blood-brain barrier and be excreted mainly through kidney. No obvious toxicity of AuNCs found in cells and in mice. Conclusion: The optimal route of AuNCs administration in mice targeting Parkinson's disease is intraperitoneal administration.

Polydopamine coated hollow mesoporous silica nanoparticles as pH-sensitive nanocarriers for overcoming multidrug resistance.

A nanocarrier system of methoxypolyethylene glycol amine (mPEG-NH2) functionalized polydopamine (PDA) coated hollow mesoporous silica nanoparticles (HMSNs-PDA-PEG) was developed with pH-responsive, which combined doxorubicin hydrochloride (DOX) and quercetin (QUR) to reverse multidrug resistance (MDR) and improved anticancer effects on taxol (TAX) and DOX double resistant human colorectal cancer cell line HCT-8 (HCT-8/TAX cells). Well-dispersed nanoparticles (HMSNs-PDA-PEG) were prepared with a dimension of around 170 nm. The surface morphology and chemical properties of HMSNs-PDA-PEG were also successfully characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), thermal gravimetric analysis (TGA), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) method, Fourier transform infrared spectroscopy (FT-IR) and dynamic light scattering (DLS). Drug release experiments results indicated that DOX and QUR (QD) loaded nanoparticles (HMSNs-PDA-PEG@QD) had similar release kinetic profiles of each drug, which all exhibited highly sensitive to pH value due to the surface PDA coating. Additionally, the HCT-8 cells or HCT-8/TAX cells were employed to assess the cellular uptake and cytotoxicity of various drug-free or drug-loaded HMSNs samples. Meanwhile, a series of biological evaluations demonstrated that the HMSNs-PDA-PEG@QD exhibited remarkable ability to overcome MDR compared with free DOX and HMSNs-PDA-PEG@DOX. Taken together, these results revealed that HMSNs-PDA-PEG@QD was suitable as a prospective and efficient drug delivery nanosystem for overcoming multidrug resistance.

The effects of biodegradation on the characteristics and disinfection by-products formation of soluble microbial products chemical fractions.

Soluble microbial products (SMPs) discharged into rivers from sewage treatment plants may increase the health risk for downstream drinking water by acting as a precursor of DBPs. Biotransformation or biodegradation could alter the characteristics of SMPs and affect the subsequent formation of DBPs. This study observed the relative contribution of chemical fractions in SMPs and explored the biodegradation of each fraction and their effect on disinfection by-products (DBPs) formation in surface water. The hydrophilic acid (HPIA) and hydrophobic acid (HPOA) constituted the major portion of the SMPs, which were dominated by fulvic acid and humic acids. The transphilic acid (TPIA) and hydrophobic bases (HPOB) were relatively minor but it contained a relative substantial portion of protein-like materials in SMPs. TPIA and HPOB produced insignificant amounts of DBP corresponding to 13% and 14% in the original samples, but they were collectively responsible for 50% of the DBPs yield. Much larger amounts of hydrophobic fractions were utilized than hydrophilic fractions after biodegradation. The increase in SUVA values indicating aromatic structures, except for HPOA fraction, was observed after biodegradation. The protein-like materials in both the HPOA and HPIA fractions and polycarboxylate-type humic acid in the HPIA fraction decreased but the enrichment of HPOA (MW > 100 kDa) and TPIA (MW < 1 kDa) was observed after biodegradation. The production of = C-H in HPIA fraction and the appearance of double peak at 1100 cm-1 in TPIA and HPOB fractions occurred after biodegradation. In overall level, microorganisms effectively utilized DBP precursors from HPIA, HPOA and HPOB fractions but increased the DBPs precursors from the TPIA fraction. TPIA and HPOB fractions had higher DBP yield with chlorine but the DBPs yield of HPIA and HPOA changed little after biodegradation.