Scaling of hysteresis loop of interacting polymers under a periodic force.

Using Langevin dynamics simulations, we study a simple model of interacting-polymer under a periodic force. The extension curves strongly depend on the magnitude of the amplitude (F) and the frequency (ν) of the applied force. In low frequency limit, the system retraces the thermodynamic path. At higher frequencies, response time is greater than the external time scale for change of force, which restrict the biomolecule to explore a smaller region of phase space that results in hysteresis of different shapes and sizes. We show the existence of dynamical transition, where area of hysteresis loop approaches to a large value from nearly zero value with decreasing frequency. The area of hysteresis loop is found to scale as F(α)ν(ß) for the fixed length. These exponents are found to be the same as of the mean field values for a time dependent hysteretic response to periodic force in case of the isotropic spin.

Thiol-Functionalized Cellulose-Grafted Copper Oxide Nanoparticles for the Therapy of Experimental Colitis in Swiss Albino Mice.

Ulcerative colitis (UC) is a chronic inflammatory disease, which deleteriously affects the lower end of the gastrointestinal tract, i.e., the colon and the rectum. UC affects colonic inflammatory homeostasis and disrupts intestinal barrier functions. Intestinal tissue damage activates the immune system and collectively worsens the disease condition via the production of various cytokines. Ongoing therapeutics of UC have marked limitations like rapid clearance, extensive first-pass metabolism, poor drug absorption, very low solubility, bioavailability, etc. Because of these restrictions, the management of UC demands a rational approach that selectively delivers the drug at the site of action to overcome the therapeutic limiting factors. Metallic nanoparticles (NPs) have good therapeutic efficacy against colitis, but their uses are limited due to adverse effects on the biological system. In this study, we have used biocompatible thiol-functionalized cellulose-grafted copper oxide nanoparticles (C-CuI/IIO NPs) to treat UC. The metal NPs alleviated the colitis condition as evidenced by the colon length and observed physical parameters. Analysis of histopathology demonstrated the recovery of the colon architecture damaged by dextran sulfate sodium-induced colitis. Treatment with C-CuI/IIO NPs reduced the disintegration of goblet cells and the retainment of sulfomucin. Significant downregulation of inflammatory markers like MPO activity, as well as levels of nitrite and TNF-α, was found following C-CuI/IIO NP treatment. The observations from the study suggested that intrarectal treatment of colitis with cellulose-based C-CuI/IIO NPs successfully combated the intestinal inflammatory condition.

Sivelestat-loaded nanostructured lipid carriers modulate oxidative and inflammatory stress in human dental pulp and mesenchymal stem cells subjected to oxygen-glucose deprivation.

Stroke remains the leading cause of morbidity and mortality. Stem cell-based therapy offers promising hope for survivors and their families. Despite the clinical translation of stem cell-based therapies in stroke patients for almost two decades, results of these randomized controlled trials are not very optimistic. In these lines, an amalgamation of nanocarriers based drug delivery with stem cells holds great promise in enhancing stroke recovery. In the present study, we treated oxygen-glucose deprivation (OGD) exposed dental pulp stem cells (DPSCs) and mesenchymal stem cells (MSCs) with sivelestat-loaded nanostructured lipid carriers (NLCs). Various physicochemical limitations associated with sivelestat drug applications and its recent inefficacy in the clinical trials necessitates the development of novel delivery approaches for sivelestat. Therefore, to improve its efficacy on the survival of DPSCs and MSCs cell types under OGD insult, the current NLCs were formulated and characterized. Resulting NLCs exhibited a hydrodynamic diameter of 160-180 nm by DLS technique and possessed good PDI values of 0.2-0.3. Their shape, size and surface morphology were corroborated with microscopic techniques like TEM, SEM, and AFM. FTIR and UV-Vis techniques confirmed nanocarrier's loading capacity, encapsulation efficiency of sivelestat, and drug release profile. Oxidative stress in DPSCs and MSCs was assessed by DHE and DCFDA staining, and cell viability was assessed by Trypan blue exclusion test and MTT assay. Results indicated that sivelestat-loaded NLCs protected the loss of cell membrane integrity and restored cell morphology. Furthermore, NLCs successfully defended human DPSCs and MSCs against OGD-induced oxidative and inflammatory stress. In conclusion, modulation of oxidative and inflammatory stress by treatment with sivelestat-loaded NLCs in DPSCs and MSCs provides a novel strategy to rescue stem cells during ischemic stroke.

Comparative acute intravenous toxicity study of triple polymer-layered magnetic nanoparticles with bare magnetic nanoparticles in Swiss albino mice.

Iron-oxide nanoparticles are one of the most commercialized nanomaterials and have gained widespread acceptance in nanotherapeutics due to their ability for targeted drug delivery, bioimaging, and various other preclinical and clinical theranostic biomedical applications. However, the absence of regulations, guidelines, and harmonized standards as well as limitations associated with their use in clinical settings in the context of their safety and toxicity profiling necessitates in-depth understanding of their toxicological paradigms. Here we examine the toxicity of modified superparamagnetic iron oxide nanoparticles in Swiss albino mice in terms of body weight changes, organ coefficients, generalized and organ-specific biochemical, and various histological staining parameters after administration of bare (uncoated) magnetic nanoparticles (MNPs) and triple polymer-coated magnetic nanoparticles (MNP-AC-G2-pPEG). Both types of nanoparticles were administered intravenously, in three doses (5, 10, and 25 mg/kg body weight) and results of biochemical and histopathological assessment revealed that the highest dose of bare (uncoated) MNPs significantly altered biochemical and histoarchitectural aspects in vital organs, while coated NPs (MNP-AC-G2-pPEG) was found safe in almost all doses. Furthermore, results of toluidine blue (for mast cells) and Prussian blue (for iron deposition) staining also established that the highest dose administration of bare MNPs in animals significantly enhanced mast cell infiltration and iron deposition in tissue sections of most vital organs, while coated NPs did not demonstrate any such adverse effects. Overall, outcomes of this study aid in establishing that administration of uncoated (bare) magnetic NPs in vivo results in structural and functional toxicological modifications while the coating of these NPs with biocompatible and biodegradable polymers can significantly bring down the toxicity of these NPs.

Leveraging thiol-functionalized biomucoadhesive hybrid nanoliposome for local therapy of ulcerative colitis.

Directly administering medication to inflamed intestinal sites for treating ulcerative colitis (UC), poses significant challenges like retention time, absorption variability, side effects, drug stability, and non-specific delivery. Recent advancements in therapy to treat colitis aim to improve local drug availability that is enema therapy at the site of inflammation, thereby reducing systemic adverse effects. Nevertheless, a key limitation lies in enemas' inability to sustain medication in the colon due to rapid peristaltic movement, diarrhea, and poor local adherence. Therefore, in this work, we have developed site-specific thiolated mucoadhesive anionic nanoliposomes to overcome the limitations of conventional enema therapy. The thiolated delivery system allows prolonged residence of the delivery system at the inflamed site in the colon, confirmed by the adhesion potential of thiolated nanoliposomes using in-vitro and in-vivo models. To further provide therapeutic efficacy thiolated nanoliposomes were loaded with gallic acid (GA), a natural compound known for its antibacterial, antioxidant, and potent anti-inflammatory properties. Consequently, Gallic Acid-loaded Thiolated 2,6 DALP DMPG (GATh@APDL) demonstrates the potential for targeted adhesion to the inflamed colon, facilitated by their small size 100 nm and anionic nature. Therapeutic studies indicate that this formulation offers protective effects by mitigating colonic inflammation, downregulating the expression of NF-κB, HIF-1α, and MMP-9, and demonstrating superior efficacy compared to the free GA enema. The encapsulated GA inhibits the NF-κB expression, leading to enhanced expression of MUC2 protein, thereby promoting mucosal healing in the colon. Furthermore, GATh@APDL effectively reduces neutrophil infiltration and regulates immune cell quantification in colonic lamina propria. Our findings suggest that GATh@APDL holds promise for alleviating UC and addressing the limitations of conventional enema therapy.