Control Release of Adenosine Potentiate Osteogenic Differentiation within a Bone Integrative EGCG-g-NOCC/Collagen Composite Scaffold toward Guided Bone Regeneration in a Critical-Sized Calvarial Defect.

The regeneration of critical-sized bone defects with biomimetic scaffolds remains clinically challenging due to avascular necrosis, chronic inflammation, and altered osteogenic activity. Two confounding mechanisms, efficacy manipulation, and temporal regulation dictate the scaffold's bone regenerative ability. Equally critical is the priming of the mesenchymal stromal cells (MSCs) toward lineage-specific differentiation into bone-forming osteoblast, which particularly depends on varied mechanochemical and biological cues during bone tissue regeneration. This study sought to design and develop an optimized osteogenic scaffold, adenosine/epigallocatechin gallate-N,O-carboxymethyl chitosan/collagen type I (AD/EGCG-g-NOCC@clgn I), having osteoinductive components toward swift bone regeneration in a calvarial defect BALB/c mice model. The ex vivo findings distinctly establish the pro-osteogenic potential of adenosine and EGCG, stimulating MSCs toward osteoblast differentiation with significantly increased expression of alkaline phosphatase, calcium deposits, and enhanced osteocalcin expression. Moreover, the 3D matrix recapitulates extracellular matrix (ECM) properties, provides a favorable microenvironment, structural support against mechanical stress, and acts as a reservoir for sustained release of osteoinductive molecules for cell differentiation, proliferation, and migration during matrix osteointegration observed. Evidence from in vivo experiments, micro-CT analyses, histology, and histomorphometry signify accelerated osteogenesis both qualitatively and quantitatively: effectual bone union with enhanced bone formation and new ossified tissue in 4 mm sized defects. Our results suggest that the optimized scaffold serves as an adjuvant to guide bone tissue regeneration in critical-sized calvarial defects with promising therapeutic efficacy.

Self-Assembling Nano-Globular Peptide from Human Lactoferrin Acts as a Systemic Enhancer of Bone Regeneration: A Novel Peptide for Orthopedic Application.

A technology for systemic and repeated administration of osteogenic factors for orthopedic use is an unmet medical need. Lactoferrin (∼80 kDa), present in milk, is known to support bone growth. We discovered a lactoferrin-mimetic peptide, LP2 (an 18-residue fragment from the N-terminus of the N-lobe of human lactoferrin), which self-assembles into a nano-globular assembly with a ß-sheet structure in an aqueous environment. LP2 is non-hemolytic and non-cytotoxic against human red blood cells and 3T3 fibroblasts, respectively, and appreciably stable in the human serum. LP2 through the bone morphogenetic protein-dependent mechanism stimulates osteoblast differentiation more potently than the full-length protein as well as the osteoblastic production of osteoprotegerin (an anti-osteoclastogenic factor). Consequently, daily subcutaneous administration of LP2 to rats and rabbits with osteotomy resulted in faster bone healing and stimulated bone formation in rats with a low bone mass more potently than that with teriparatide, the standard-of-care osteogenic peptide for osteoporosis. LP2 has skeletal bioavailability and is safe at the 15× osteogenic dose. Thus, LP2 is a novel peptide that can be administered systemically for the medical management of hard-to-heal fractures.

Inhibition of Thioredoxin Reductase by Targeted Selenopolymeric Nanocarriers Synergizes the Therapeutic Efficacy of Doxorubicin in MCF7 Human Breast Cancer Cells.

Increasing evidence suggests selenium nanoparticles (Se NPs) as potential cancer therapeutic agents and emerging drug delivery carriers, yet, the molecular mechanism of their anticancer activity still remains unclear. Recent studies indicate thioredoxin reductase (TrxR), a selenoenzyme, as a promising target for anticancer therapy. The present study explored the TrxR inhibition efficacy of Se NPs as a plausible factor impeding tumor growth. Hyaluronic acid (HA)-functionalized selenopolymeric nanocarriers (Se@CMHA NPs) were designed wielding chemotherapeutic potential for target specific Doxorubicin (DOX) delivery. Se@CMHA nanocarriers are thoroughly characterized asserting their chemical and physical integrity and possess prolonged stability. DOX-loaded selenopolymeric nanocarriers (Se@CMHA-DOX NPs) exhibited enhanced cytotoxic potential toward human cancer cells compared to free DOX in an equivalent concentration eliciting its selectivity. In first-of-its-kind findings, selenium as Se NPs in these polymeric carriers progressively inhibit TrxR activity, further augmenting the anticancer efficacy of DOX through a synergistic interplay between DOX and Se NPs. Detailed molecular studies on MCF7 cells also established that upon exposure to Se@CMHA-DOX NPs, MCF7 cells endure G2/M cell cycle arrest and p53-mediated caspase-independent apoptosis. To gauge the relevance of the developed nanosystem in in vivo settings, three-dimensional tumor sphere model mimicking the overall tumor environment was also performed, and the results clearly depict the effectiveness of our nanocarriers in reducing tumor activity. These findings are reminiscent of the fact that our Se@CMHA-DOX NPs could be a viable modality for effective cancer chemotherapy.

Statistical optimization and artificial neural network modeling for acridine orange dye degradation using in-situ synthesized polymer capped ZnO nanoparticles.

ZnO NPs were synthesized by a prudent green chemistry approach in presence of polyacrylamide grafted guar gum polymer (pAAm-g-GG) to ensure uniform morphology, and functionality and appraised for their ability to degrade photocatalytically Acridine Orange (AO) dye. These ZnO@pAAm-g-GG NPs were thoroughly characterized by various spectroscopic, XRD and electron microscopic techniques. The relative quantity of ZnO NPs in polymeric matrix has been estimated by spectro-analytical procedure; AAS and TGA analysis. The impact of process parameters viz. NP's dose, contact time and AO dye concentration on percentage photocatalytic degradation of AO dyes were evaluated using multivariate optimizing tools, Response Surface Methodology (RSM) involving Box-Behnken Design (BBD) and Artificial Neural Network (ANN). Congruity of the BBD statistical model was implied by R2 value 0.9786 and F-value 35.48. At RSM predicted optimal condition viz. ZnO@pAAm-g-GG NP's dose of 0.2g/L, contact time of 210min and AO dye concentration 10mg/L, a maximum of 98% dye degradation was obtained. ANOVA indicated appropriateness of the model for dye degradation owing to "Prob.>F" less than 0.05 for variable parameters. We further, employed three layers feed forward ANN model for validating the BBD process parameters and suitability of our chosen model. The evaluation of Levenberg-Marquardt algorithm (ANN1) and Gradient Descent with adaptive learning rate (ANN2) model employed to scrutinize the best method and found experimental values of AO dye degradation were in close to those with predicated value of ANN 2 modeling with minimum error.

Targeted Smart pH and Thermoresponsive N,O-Carboxymethyl Chitosan Conjugated Nanogels for Enhanced Therapeutic Efficacy of Doxorubicin in MCF-7 Breast Cancer Cells.

In cancer treatment, developing ideal anticancer drug delivery systems to target tumor microenvironment by circumventing various physiological barriers still remains a daunting challenge. Here, in our work, a series of pH- and temperature-responsive nanogels based on poly(N-isopropylacrylamide-co-1-propene-2-3-dicarboxylate-co-2-acrylamido-2-methyl-1-propanesulfonate [poly(NIPAAm-IA-AMPS)] cross-linked by ethylene glycol dimethacrylate (EGDMA) were synthesized by random copolymerization. The molar ratio between monomer-comonomers-cross-linker was varied to fine-tune the optimum responsiveness of the nanogels. These optimized nanogels were further coupled to N,O-carboxymethyl chitosan (NOCC) stoichiometrically using EDC-NHS coupling chemistry to enhance the swelling behavior at lower pH. Interestingly, these NOCC-g-nanogels, when dispersed in aqueous media under sonication, attain nanosize and retain their high water-retention capacity with conspicuous pH and temperature responsiveness (viz. nanogel shrinkage in size beyond 35 °C and swelled at acidic pH) in vitro, as reflected by dynamic light scattering data. Doxorubicin (DOX), a potent anticancer drug, was loaded into these nanogels using the physical entrapment method. These drug-loaded nanogels exhibited a slow and sustained DOX release profile at physiological temperature and cytosolic pH. Furthermore, confocal and TEM results demonstrate that these nanogels were swiftly internalized by MCF-7 cells, and cell viability data showed preferential heightened cytotoxicity toward cancer cells (MCF-7 and MDA-MB231) compared to the MCF10A cells (human breast epithelial cell). Furthermore, intracellular DNA damage and cell cycle arrest assays suggest a mitochondrial mediated apoptosis in MCF-7 cells. This study substantiates our NOCC-g-nanogel platform as an excellent modality for passive diffusive loading and targeted release of entrapped drug(s) at physiological conditions in a controlled way for the improved therapeutic efficacy of the drug in anticancer treatment.