Development of QSARs for cysteine-containing di- and tripeptides with antioxidant activity:influence of the cysteine position.

Antioxidants agents play an essential role in the food industry for improving the oxidative stability of food products. In the last years, the search for new natural antioxidants has increased due to the potential high toxicity of chemical additives. Therefore, the synthesis and evaluation of the antioxidant activity in peptides is a field of current research. In this study, we performed a Quantitative Structure Activity Relationship analysis (QSAR) of cysteine-containing 19 dipeptides and 19 tripeptides. The main objective is to bring information on the relationship between the structure of peptides and their antioxidant activity. For this purpose, 1D and 2D molecular descriptors were calculated using the PaDEL software, which provides information about the structure, shape, size, charge, polarity, solubility and other aspects of the compounds. Different QSAR model for di- and tripeptides were developed. The statistic parameters for di-peptides model (R2train = 0.947 and R2test = 0.804) and for tripeptide models (R2train = 0.923 and R2test = 0.847) indicate that the generated models have high predictive capacity. Then, the influence of the cysteine position was analyzed predicting the antioxidant activity for new di- and tripeptides, and comparing them with glutathione. In dipeptides, excepting SC, TC and VC, the activity increases when cysteine is at the N-terminal position. For tripeptides, we observed a notable increase in activity when cysteine is placed in the N-terminal position.

iRGD-Guided Silica/Gold Nanoparticles for Efficient Tumor-Targeting and Enhancing Antitumor Efficacy Against Breast Cancer.

Background: Breast cancer presents significant challenges due to the limited effectiveness of available treatments and the high likelihood of recurrence. iRGD possesses both RGD sequence and C-terminal sequence and has dual functions of targeting and membrane penetration. iRGD-modified nanocarriers can enhance drug targeting of tumor vascular endothelial cells and penetration of new microvessels, increasing drug concentration in tumor tissues. Methods: The amidation reaction was carried out between SiO2/AuNCs and iRGD/PTX, yielding a conjugated drug delivery system (SiO2/AuNCs-iRGD/PTX, SAIP@NPs). The assessment encompassed the characterization of the morphology, particle size distribution, physicochemical properties, in vitro release profile, cytotoxicity, and cellular uptake of SAIP@NPs. The tumor targeting and anti-tumor efficacy of SAIP@NPs were assessed using a small animal in vivo imaging system and a tumor-bearing nude mice model, respectively. The tumor targeting and anti-tumor efficacy of SAIP@NPs were assessed utilizing a small animal in vivo imaging system and an in situ nude mice breast cancer xenograft model, respectively. Results: The prepared SAIP@NPs exhibited decent stability and a certain slow-release effect in phosphate buffer (PBS, pH 7.4). In vitro studies had shown that, due to the dual functions of transmembrane and targeting of iRGD peptide, SAIP@NPs exhibited strong binding to integrin αvß3, which was highly expressed on the membrane of MDA-MB-231 cells, improving the uptake capacity of tumor cells, inhibiting the rapid growth of tumor cells, and promoting tumor cell apoptosis. The results of animal experiments further proved that SAIP@NPs had longer residence time in tumor sites, stronger anti-tumor effect, and no obvious toxicity to major organs of experimental animals. Conclusion: The engineered SAIP@NPs exhibited superior functionalities including efficient membrane permeability, precise tumor targeting, and imaging, thereby significantly augmenting the therapeutic efficacy against breast cancer with a favorable safety profile.

Targeted 8-arm PEG Nanosystems for Localization of Choroidal Neovascularization Macular Degeneration Model.

8-arm PEG (polyethylene-glycol) is a highly promising nanoplatform due to its small size (<10 nm), ease-of-conjugation (many functionalized variants are readily available with "click-like" properties), biocompatibility, and optical inactivity. This study evaluates 8-arm PEG uptake into cells (in vitro) and localization and clearance in vasculature (in vivo) for targeting of choroidal neovascularization in mice, an animal model of macular degeneration. 8-arm PEG nanoparticles were labeled with fluorescein isothiocyanate (FITC) and functionalized in the absence or presence of pentameric Ar-Gly-Asp (RGD; 4 RGD motifs and a PGC linker), one of the most common peptide motifs used for active targeting. In vitro studies show that RGD-conjugated 8-arm PEG nanoparticles exhibit enhanced cellular uptake relative to non-RGD-conjugated control NPs at 34% ± 9%. Laser-induced choroidal neovascularization (CNV) was performed in a mouse model to measure 8-arm PEG localization and clearance to model macular degeneration lesions in vivo. It was determined that both RGD-conjugated and non-RGD-conjugated (nRGD) 8-arm PEG particles localized to CNV lesions, with a half-life around 24 h. In vivo experiments showed that RGD-conjugated nanoparticles exhibited enhanced localization by 15-20% relative to without RGD controls. Exhibiting a high rate of localization and fast clearance relative to larger nanoparticles, targeted 8-arm PEG nanoparticles with a conjugated RGD-peptide could be a promising modality for macular degeneration diagnosis and therapy.

PLCL/SF/NGF nerve conduit loaded with RGD-TA-PPY hydrogel promotes regeneration of sciatic nerve defects in rats through PI3K/AKT signalling pathways.

Peripheral nerve defect are common clinical problem caused by trauma or other diseases, often leading to the loss of sensory and motor function in patients. Autologous nerve transplantation has been the gold standard for repairing peripheral nerve defects, but its clinical application is limited due to insufficient donor tissue. In recent years, the application of tissue engineering methods to synthesize nerve conduits for treating peripheral nerve defect has become a current research focus. This study introduces a novel approach for treating peripheral nerve defects using a tissue-engineered PLCL/SF/NGF@TA-PPy-RGD conduit. The conduit was fabricated by combining electrospun PLCL/SF with an NGF-loaded conductive TA-PPy-RGD gel. The gel, synthesized from RGD-modified tannic acid (TA) and polypyrrole (PPy), provides growth anchor points for nerve cells. In vitro results showed that this hybrid conduit could enhance PC12 cell proliferation, migration, and reduce apoptosis under oxidative stress. Furthermore, the conduit activated the PI3K/AKT signalling pathway in PC12 cells. In a rat model of sciatic nerve defect, the PLCL/SF/NGF@TA-PPy-RGD conduit significantly improved motor function, gastrocnemius muscle function, and myelin sheath axon thickness, comparable to autologous nerve transplantation. It also promoted angiogenesis around the nerve defect. This study suggests that PLCL/SF/NGF@TA-PPy-RGD conduits provide a conducive environment for nerve regeneration, offering a new strategy for peripheral nerve defect treatment, this study provided theoretical basis and new strategies for the research and treatment of peripheral nerve defect.

Purification and biochemical characterization of methanobactin biosynthetic enzymes.

Methanobactin (Mbn) is a ribosomally synthesized and post-translationally modified peptide (RiPP) natural product that binds Cu(I) with high affinity. The copper-chelating thioamide/oxazolone groups in Mbn are installed on the precursor peptide MbnA by the core enzyme complex, MbnBC, which includes the multinuclear non-heme iron-dependent oxidase (MNIO) MbnB and its RiPP recognition element-containing partner protein MbnC. For the extensively characterized Mbn biosynthetic gene cluster (BGC) from the methanotroph Methylosinus trichosporium OB3b, the tailoring aminotransferase MbnN further modifies MbnA after leader sequence cleavage by an unknown mechanism. Here we detail methods to express and purify M. trichosporium OB3b MbnBC and MbnN along with protocols for assessing MbnA modification by MbnBC and MbnN aminotransferase activity. In addition, we describe crystallization and structure determination of MbnBC. These procedures can be adapted for other MNIOs and partner proteins encoded in Mbn and Mbn-like BGCs. Furthermore, these methods provide a first step toward in vitro biosynthesis of Mbns and related natural products as potential therapeutics.

Development of modular polymeric nanoparticles for drug delivery using amine reactive chemistry.

Curcumin has been explored for its anti-cancer potential, but is severely limited by its hydrophobicity and sensitivity to light and water. In this study, poly (lactic-co-glycolic) acid (PLGA) nanoparticles (NPs) were synthesized to encapsulate curcumin via single emulsion method to improve curcumin stability and bioavailability. The PLGA NPs were coated with oligomeric chitosan (COS) and RGD peptide (a peptide consisting of Arg-Gly-Asp) using amine-reactive chemistry (NHS and EDC). Both COS and RGD had been previously shown to accumulate and target many different types of cancer cells. NPs were characterised based on size distribution, zeta potential, and binding efficiency of RGD peptide. They were also evaluated on encapsulation efficiency, and stability, of curcumin within the NPs. OVCAR-3 cancer cells were treated with COS and RGD-coated PLGA NPs loaded with Coumarin-6 dye for fluorescent imaging of cell uptake. They were also treated with curcumin-loaded NPs to determine cytotoxicity and effectiveness of delivery. The NPs exhibited size distribution and zeta potential within expected values, though binding efficiency of RGD was low. Curcumin-loaded NPs showed significant increase in cytotoxicity over free (unencapsulated) curcumin, and void (empty) NPs, suggesting successful delivery of curcumin as an anti-cancer agent; the performance of COS and RGD coated NPs over bare PLGA NPs was inconclusive, however, optimization will be required to improve formulation during the coating steps. This method of NP synthesis serves as proof of concept for a modular solution to the development of various coated polymeric NPs for other drugs or applications.

Drug delivery under cover of erythrocytes extends drug half-life: A thrombolytic targeting therapy utilizing microenvironment-responsive artificial polysaccharide microvesicles.

The development of thrombolytic drug carriers capable of thrombus-targeting, prolonged circulation time, intelligent responsive release, and the ability to inhibit thrombotic recurrences remains a promising but significant challenge. To tackle this, an artificial polysaccharide microvesicle drug delivery system (uPA-CS/HS@RGD-ODE) was constructed. It is composed of cationic chitosan and anionic heparin assembled in a layer by layer structure, followed by surface modification using RGD peptide and 2-(N-oxide-N,N-diethylamino) ethylmethacrylate (ODE) before encapsulation of urokinase-type plasminogen activator (uPA). The effect of chitosan on the basic performances of uPA-CS/HS@RGD-ODE was estimated. The in vitro results suggest the uPA carrier, CS/HS@RGD-ODE, displayed outstanding targeting specific to activated platelets (61 %) and microenvironment-responsiveness at pH 6.5, facilitating thrombus-targeting and a controlled drug release, respectively. Most importantly, in vivo experiment suggests ODE from uPA-CS/HS@RGD-ODE substantially extends the half-life of uPA (120 min), as uPA-CS/HS@RGD-ODE can adhere onto erythrocytes and deliver uPA under cover of erythrocytes enabling a prolonged circulation time in the bloodstream. Further tail vein and abdominal aorta thrombosis models confirmed uPA-CS/HS@RGD-ODE exhibited superior targeting and thrombolysis capabilities compared to systemic administration of free uPA. To the knowledge of authors, this may be the first study to develop new drug carriers for delivery of thrombolytic drugs under the cover of erythrocytes for extended drug half-lives.

Structure and fragmentation chemistry of the peptide radical cations of glycylphenylalanylglycine (GFG).

Herein, we explore the generation and characterization of the radical cations of glycylphenylalanylglycine, or [GFG]•+, formed via dissociative electron-transfer reaction from the tripeptide to copper(II) within a ternary complex. A comprehensive investigation employing isotopic labeling, infrared multiple-photon dissociation (IRMPD) spectroscopy, and density functional theory (DFT) calculations elucidated the details and energetics in formation of the peptide radical cations as well as their dissociation products. Unlike conventional aromatic-containing peptide radical cations that primarily form canonical π-radicals, our findings reveal that 75% of the population of the experimentally produced [GFG]•+ precursors are [GFα•G]+, where the radical resides on the middle α-carbon of the phenylalanyl residue. This unexpected isomeric ion has an enthalpy of 6.8 kcal/mol above the global minimum, which has an N-terminal captodative structure, [Gα•FG]+, comprising 25% of the population. The [b2-H]•+ product ions are also present in a ratio of 75/25 from [GFα•G]+/ [Gα•FG]+, the results of which are obtained from matches between the IRMPD action spectrum and predicted IR absorption spectra of the [b2-H]•+ candidate structures, as well as from IRMPD isomer population analyses.

The Effects of the Carrier and Ligand Spatial Conformation on RNA Nanodrug Cell Delivery.

Small interfering RNA (siRNA) highlights the immense therapeutic potential for cancer treatment. The major challenge in siRNA therapy is the effective RNA nanodrug delivery system, which is facilitated by the ligand and the carrier. In this study, we analyzed the binding specificity of linear RGD and circular RGD to αVß3 integrins by mapping the morphology using super-resolution direct stochastic optical reconstruction microscopy. Meanwhile, the binding dynamics was investigated using single-molecule force spectroscopy. Then, the effects of the ligand and carrier on RNA nanodrug cell entry dynamic parameters were evaluated at the single particle level by the force tracing technique. Furthermore, the delivery efficiency of RNA nanodrugs was assessed using AFM-based nanoindentation at the single cell level. This report will provide valuable insights for rational design strategies aiming to achieve improved efficiency for nanodrug delivery systems.

Immobilized Drugs on Dual-Mode Imaging Ag2S/BaSO4/PVA Embolic Microspheres for Precise Localization, Rapid Embolization, and Local Antitumor Therapy.

Transcatheter arterial embolization (TAE) in interventional therapy and tumor embolism therapy plays a significant role. The choice of embolic materials that have good biocompatibility is an essential component of TAE. For this study, we produced a multifunctional PVA embolization material that can simultaneously encapsulate Ag2S quantum dots (Ag2S QDs) and BaSO4 nanoparticles (BaSO4 NPs), exhibiting excellent second near-infrared window (NIR-II) fluorescence imaging and X-ray imaging, breaking through the limitations of traditional embolic microsphere X-ray imaging. To improve the therapeutic effectiveness against tumors, we doped the doxorubicin (DOX) antitumor drug into microspheres and combined it with a clotting peptide (RADA16-I) on the surface of microspheres. Thus, it not only embolizes rapidly during hemostasis but also continues to release and accelerate tumor necrosis. In addition, Ag2S/BaSO4/PVA microspheres (Ag2S/BaSO4/PVA Ms) exhibited good blood compatibility and biocompatibility, and the results of embolization experiments on renal arteries in rabbits revealed good embolic effects and bimodal imaging stability. Therefore, they could serve as a promising medication delivery embolic system and an efficient biomaterial for arterial embolization. Our research work achieves the applicability of NIR-II and X-ray dual-mode images for clinical embolization in biomedical imaging.

Gold(III)-Induced Amide Bond Cleavage In Vivo: A Dual Release Strategy via π-Acid Mediated Allyl Substitution.

Selective cleavage of amide bonds holds prominent significance by facilitating precise manipulation of biomolecules, with implications spanning from basic research to therapeutic interventions. However, achieving selective cleavage of amide bonds via mild synthetic chemistry routes poses a critical challenge. Here, we report a novel amide bond-cleavage reaction triggered by Na[AuCl4] in mild aqueous conditions, where a crucial cyclization step leads to the formation of a 5-membered ring intermediate that rapidly hydrolyses to release the free amine in high yields. Notably, the reaction exhibits remarkable site-specificity to cleave peptide bonds at the C-terminus of allyl-glycine. The strategic introduction of a leaving group at the allyl position facilitated a dual-release approach through π-acid catalyzed substitution. This reaction was employed for the targeted release of the cytotoxic drug monomethyl auristatin E in combination with an antibody-drug conjugate in cancer cells. Finally, Au-mediated prodrug activation was shown in a colorectal zebrafish xenograft model, leading to a significant increase in apoptosis and tumor shrinkage. Our findings reveal a novel metal-based cleavable reaction expanding the utility of Au complexes beyond catalysis to encompass bond-cleavage reactions for cancer therapy.

Combined Effects of Anti-PD-L1 and Nanosonodynamic Therapy on HCC Immune Activation in Mice: An Investigation.

Introduction: Current therapeutic strategies, including immune checkpoint blockade (ICB), exhibit limited efficacy in treating hepatocellular carcinoma (HCC). Nanoparticles, particularly those that can accumulate specifically within tumors and be activated by sonodynamic therapy (SDT), can induce immunogenic cell death (ICD); however, ICD alone has not achieved satisfactory therapeutic effectiveness. This study investigates whether combining ICB with ICD induced by nanoparticle-mediated SDT could enhance anti-tumor immunity and inhibit HCC growth. Methods: We developed an iron-based micelle nanodelivery system encapsulating the Near-Infrared Dye IR-780, which was surface-modified with a cyclic tripeptide composed of arginine-glycine-aspartic acid (cRGD). This led to the synthesis of targeted IR780@FOM-cRGD nanoparticles. These nanoparticles were specifically engineered to kill tumor cells under sonication, activate immunogenic cell death (ICD), and be used in conjunction with immune checkpoint blockade (ICB) for the treatment of hepatocellular carcinoma (HCC). Results: The synthesized IR780@FOM-cRGD nanoparticles had an average diameter of 28.23±1.750 nm and a Zeta potential of -23.95±1.926. Confocal microscopy demonstrated that IR780@FOM-cRGD could target HCC cells while minimizing toxicity to healthy cells. Upon sonodynamic activation, these nanoparticles consumed significant amounts of oxygen and generated substantial reactive oxygen species (ROS), effectively killing tumor cells and inhibiting the proliferation, invasion, and migration of H22 cells. Hemolysis assays confirmed the in vivo safety of the nanoparticles, and in vivo fluorescence imaging revealed significant accumulation in tumor tissues. Mouse model experiments showed that combining ICB(which induced by Anti-PD-L1) with ICD (which induced by IR780@FOM-cRGD), could effectively activated anti-tumor immunity and suppressed tumor growth. Discussion: This study highlights the potential of IR780@FOM-cRGD nanoparticles to facilitate tumor eradication and immune activation when used in conjunction with Anti-PD-L1 therapy. This combination represents a non-invasive, efficient, and targeted approach for the treatment of hepatocellular carcinoma (HCC). By integrating sonodynamic therapy with immunotherapy, this strategy promises to substantially improve the effectiveness of traditional treatments in combating HCC, offering new avenues for clinical application and therapeutic innovation.

Integrating Bioactive Graded Hydrogel with Radially Aligned Nanofibers to Dynamically Manipulate Wound Healing Process.

Skin wound healing is a complex process that requires appropriate treatment and management. Using a single scaffold to dynamically manipulate angiogenesis, cell migration and proliferation, and tissue reconstruction during skin wound healing is a great challenge. We developed a hybrid scaffold platform that integrates the spatiotemporal delivery of bioactive cues with topographical cues to dynamically manipulate the wound-healing process. The scaffold comprised gelatin methacryloyl hydrogels and electrospun poly(ε-caprolactone)/gelatin nanofibers. The hydrogels had graded cross-linking densities and were loaded with two different functional bioactive peptides. The nanofibers comprised a radially aligned nanofiber array layer and a layer of random fibers. During the early stages of wound healing, the KLTWQELYQLKYKGI peptide, which mimics vascular endothelial growth factor, was released from the inner layer of the hydrogel to accelerate angiogenesis. During the later stages of wound healing, the IKVAVS peptide, which promotes cell migration, synergized with the radially aligned nanofiber membrane to promote cell migration, while the nanofiber membrane also supported further cell proliferation. In an in vivo rat skin wound-healing model, the hybrid scaffold significantly accelerated wound healing and collagen deposition, and the ratio of type I to type III collagen at the wound site resembled that of normal skin. The prepared scaffold dynamically regulated the skin tissue regeneration process in stages to achieve rapid wound repair with clinical application potential, providing a strategy for skin wound repair.

Tripeptide linked dispiro cyclotriphosphazene conjugates: Synthesis, molecular docking analysis of compounds binding within cancer cell line receptors and in vitro cytotoxic and genotoxic activities.

The novel dioxybiphenyl bridged-cyclotriphosphazenes (DPP) bearing tripeptide were synthesized and investigated for their molecular docking analysis, visualizing their binding profiles within various cancer cell line receptors and in vitro cytotoxic and genotoxic properties. The dipeptide compound (Tyr-Phe) was treated with various amino acids to obtain the tripeptide compounds (Tyr-Phe-Gly, Tyr-Phe-Ala, Tyr-Phe-Val, Tyr-Phe-Phe, and Tyr-Phe-Leu). These synthesized tripeptides were subsequently treated with DPP to obtain novel phosphazene compounds bearing tripeptide structures. As a result, the synthesis of target molecules with phosphazene compound in the center and biphenyl and tripeptide groups in the side arms was obtained for the first time in this study. Examining the cytotoxic studies in vitro of our newly synthesized compounds demonstrated the anticancer properties against four selected human cancer cell lines, including breast (MCF-7), ovarian (A2780), prostate (PC-3), and colon (Caco-2) cancer cells. The Comet Assay analysis determined that the cell death mechanism of most of the compounds with cytotoxic activity stemmed from the DNA damage mechanism. Among the compounds, the DPP-Tyr-Phe-Phe compound seems to have the best anticancer activity against the subjected cell lines (Except for A2780) with IC50 values equal to 20.18, 72.14, 12.21, and 5.17 µM against breast, ovarian, prostate, and colon cancer cell lines, respectively. For this reason, the molecular docking analysis was conducted for the DTPP compound to visualize its binding geometry and profile within the target enzyme's binding site associated with the specific cancer cell line. The analysis revealed that the DTPP derivative exhibited an optimal binding conformation and characteristics within the target enzyme's binding site, aligning well with the experimental data. Based on the data, these compounds are believed to be strong candidate molecules for both pharmaceutical and clinical applications.

Antimicrobial Activity of Positively Charged Oligopeptides with Theoretical High α-Helix Content against Cutibacterium acnes.

Cutibacterium acnes is abundant and commonly exists as a superficial bacteria on human skin. Recently, the resistance of C. acnes to antimicrobial agents has become a serious concern, necessitating the development of alternative pharmaceutical products with antimicrobial activity against C. acnes. To address this need, we evaluated the antimicrobial activity of CKR-13-a mutant oligopeptide of FK-13 with increased net charge and theoretical α-helical content-against C. acnes in modified Gifu Anaerobic Medium broth by determining the minimum inhibitory concentration (MIC). CKR-13 exerted greater antimicrobial activity against C. acnes than FK-13 in the broth at pH 7.0. The antimicrobial activity of CKR-13 with RXM against C. albicans was pH-dependent. The ionization of CKR-13 and pH-dependent growth delay of C. albicans was suggested to be associated with the increase in CKR-13 antimicrobial activity.

An Investigation into the In Vitro Targeted Killing of CD44-Expressing Triple-Negative Breast Cancer Cells Using Recombinant Photoimmunotherapeutics Compared to Auristatin-F-Based Antibody-Drug Conjugates.

Triple-negative breast cancer (TNBC) is the deadliest form of breast cancer with limited treatment options. The persistence of highly tumorigenic CD44-expressing subpopulation referred to as cancer stem cells (CSCs), endowed with the self-renewal capacity, has been associated with therapeutic resistance, hence clinical relapses. To mitigate these undesired events, targeted immunotherapies using antibody-photoconjugate (APC) or antibody-drug conjugate (ADC), were developed to specifically release cytotoxic payloads within targeted cells overexpressing cognate antigen receptors. Therefore, an αCD44(scFv)-SNAP-tag antibody fusion protein was engineered through genetic fusion of a single-chain antibody fragment (scFv) to a SNAPf-tag fusion protein, capable of self-conjugating with benzylguanine-modified light-sensitive near-infrared (NIR) phthalocyanine dye IRDye700DX (BG-IR700) or the small molecule toxin auristatin-F (BG-AURIF). Binding of the αCD44(scFv)-SNAPf-IR700 photoimmunoconjugate to antigen-positive cells was demonstrated by confocal microscopy and flow cytometry. By switching to NIR irradiation, CD44-expressing TNBC was selectively killed through induced phototoxic activities. Likewise, the αCD44(scFv)-SNAPf-AURIF immunoconjugate was able to selectively accumulate within targeted cells and significantly reduced cell viability through antimitotic activities at nano- to micromolar drug concentrations. This study provides an in vitro proof-of-concept for a future strategy to selectively destroy light-accessible superficial CD44-expressing TNBC tumors and their metastatic lesions which are inaccessible to therapeutic light.

Photo-induced imine reduction by a photoredox biocatalyst consisting of a pentapeptide and a Ru bipyridine terpyridine complex.

Imine reduction is a useful reaction in the preparation of amine derivatives. Various catalysts have been reported to promote this reaction and photoredox catalysts are promising candidates for sustainable amine synthesis. Improvement of this reaction using biomolecule-based reaction scaffolds is expected to increase the utility of the reaction. In this context, we have recently investigated photoredox Ru complexes with pentapeptide scaffolds via coordination bonds as catalysts for photoreduction of dihydroisoquinoline derivatives. First, Ru bipyridine terpyridine complexes coordinated with five different pentapeptides (XVHVV: X = V, F, W, Y, C) were prepared and characterized by mass spectrometry. Catalytic activities of the Ru complexes with XVHVV were evaluated for photoreduction of dihydroisoquinoline derivatives in the presence of ascorbate and thiol compounds as sacrificial reagents and hydrogen sources. Interestingly, the turnover number of the Ru complex with VVHVV is 531, which is two-fold higher than that of a simple Ru complex with an imidazole ligand. The detailed emission lifetime measurements indicate that the enhanced catalytic activity provided by the peptide scaffold is caused by an efficient reaction with the thiol derivative to accelerate reductive quenching of Ru complex. The quenching behavior suggests formation of an active species such as a Ru(I) complex. These findings reveal that the simple pentapeptide serves as an effective scaffold to enhance the photocatalytic activity of a photoactive Ru complex.

In-silico screening of missense nsSNPs in Delta-opioid receptor protein and their restoring tendency on MCRT interaction; focusing on dynamic nature.

Delta-opioid receptor protein (OPRD1) is one of the potential targets for treating pain. The presently available opioid agonists are known to cause unnecessary side effects. To discover a novel opioid agonist, our research group has synthesized a chimeric peptide MCRT and proved its potential activity through in vivo analysis. Non-synonymous SNPs (nsSNPs) missense mutations affect the functionality and stability of proteins leading to diseases. The current research was focused on understanding the role of MCRT in restoring the binding tendency of OPRD1 nsSNPs missense mutations on dynamic nature in comparison with Deltorphin-II and morphiceptin. The deleterious effects of nsSNPs were analyzed using various bioinformatics tools for predicting structural, functional, and oncogenic influence. The shortlisted nine nsSNPs were predicted for allergic reactions, domain changes, post-translation modification, multiple sequence alignment, secondary structure, molecular dynamic simulation (MDS), and peptide docking influence. Further, the docked complex of three shortlisted deleterious nsSNPs was analyzed using an MDS study, and the highly deleterious shortlisted nsSNP A149T was further analyzed for higher trajectory analysis. MCRT restored the binding tendency influence caused by nsSNPs on the dynamics of stability, functionality, binding affinity, secondary structure, residues connection, motion, and folding of OPRD1 protein.

Transforming Cell-Drug Interaction through Granular Hydrogel-Mediated Delivery of Polyplex Nanoparticles for Enhanced Safety and Extended Efficacy in Gene Therapy.

The utilization of hydrogels for DNA/cationic polymer polyplex nanoparticle (polyplex) delivery has significantly advanced gene therapy in tissue regeneration and cancer treatment. However, persistent challenges related to the efficacy and safety of encapsulated polyplexes, stemming from issues such as aggregation, degradation, or difficulties in controlled release during or postintegration with hydrogel scaffolds, necessitate further exploration. Here, we introduce an injectable gene therapy gel achieved by incorporating concentrated polyplexes onto densely packed hydrogel microparticles (HMPs). Polyplexes, when uniformly adhered to the gene therapy gel through reversible electrostatic interactions, can detach from the HMP surface in a controlled manner, contrasting with free polyplexes, and thereby reducing dose-dependent toxicity during transfection. Additionally, the integration of RGD cell adhesion peptides enhances the scaffolding characteristics of the gel, facilitating cell adhesion, migration, and further minimizing toxicity during gene drug administration. Notably, despite the overall transfection efficiency showing average performance, utilizing confocal microscopy to meticulously observe and analyze the cellular states infiltrating into various depths of the gene therapy gel resulted in the groundbreaking discovery of significantly enhanced local transfection efficiency, with primary cell transfection approaching 80%. This phenomenon could be potentially attributed to the granular hydrogel-mediated delivery of polyplex nanoparticles, which revolutionizes the spatial and temporal distribution and thus the "encounter" mode between polyplexes and cells. Moreover, the gene therapy gel's intrinsic injectability and self-healing properties offer ease of administration, making it a highly promising candidate as a novel gene transfection gel dressing with significant potential across various fields, including regenerative medicine and innovative living materials.

Integrating Mechanics and Bioactivity: A Detailed Assessment of Elasticity and Viscoelasticity at Different Scales in 2D Biofunctionalized PEGDA Hydrogels for Targeted Bone Regeneration.

Methods for promoting and controlling the differentiation of human mesenchymal stem cells (hMSCs) in vitro before in vivo transplantation are crucial for the advancement of tissue engineering and regenerative medicine. In this study, we developed poly(ethylene glycol) diacrylate (PEGDA) hydrogels with tunable mechanical properties, including elasticity and viscoelasticity, coupled with bioactivity achieved through the immobilization of a mixture of RGD and a mimetic peptide of the BMP-2 protein. Despite the key relevance of hydrogel mechanical properties for cell culture, a standard for its characterization has not been proposed, and comparisons between studies are challenging due to the different techniques employed. Here, a comprehensive approach was employed to characterize the elasticity and viscoelasticity of these hydrogels, integrating compression testing, rheology, and atomic force microscopy (AFM) microindentation. Distinct mechanical behaviors were observed across different PEGDA compositions, and some consistent trends across multiple techniques were identified. Using a photoactivated cross-linker, we controlled the functionalization density independently of the mechanical properties. X-ray photoelectrin spectroscopy and fluorescence microscopy were employed to evaluate the functionalization density of the materials before the culturing of hMSCs on them. The cells cultured on all functionalized hydrogels expressed an early osteoblast marker (Runx2) after 2 weeks, even in the absence of a differentiation-inducing medium compared to our controls. Additionally, after only 1 week of culture with osteogenic differentiation medium, cells showed accelerated differentiation, with clear morphological differences observed among cells in the different conditions. Notably, cells on stiff but stress-relaxing hydrogels exhibited an overexpression of the osteocyte marker E11. This suggests that the combination of the functionalization procedure with the mechanical properties of the hydrogel provides a potent approach to promoting the osteogenic differentiation of hMSCs.