Retraction: Radio frequency triggered curcumin delivery from thermo and pH responsive nanoparticles containing gold nanoparticles and its in vivo localization studies in an orthotopic breast tumor model.

[This retracts the article DOI: 10.1039/C4RA05727A.].

Correction to: Antimicrobial Drugs Encapsulated in Fibrin Nanoparticles for Treating Microbial Infested Wounds.

In the original manuscript, the Figure 2 a-i is inadvertently repeated as Figure 2 a-ii. This mistake has been rectified and the corrected Figure 2 is presented below.

Correction: Flexible, micro-porous chitosan-gelatin hydrogel/nanofibrin composite bandages for treating burn wounds.

[This corrects the article DOI: 10.1039/C4RA11969J.].

Multi Drug Loaded Thermo-Responsive Fibrinogen-graft-Poly(N-vinyl Caprolactam) Nanogels for Breast Cancer Drug Delivery.

This study aims at the targeted delivery of 5-fluorouracil (5-FU) and Megestrol acetate (Meg) loaded fibrinogen-graft-poly(N-Vinyl caprolactam) nanogels (5-FU/Meg-fib-graft-PNVCL NGs) toward α5ß1-integrins receptors expressed on breast cancer cells to have enhanced anti-cancer effect in vitro. To achieve this aim, we developed biocompatible thermoresponsive fib-graft-PNVCL NGs using fibrinogen and carboxyl terminated PNVCL via EDC/NHS amidation reaction. The Lower Critical Solution Temperature (LCST) of fib-graft-PNVCL could be tuned according to PNVCL/fibrinogen compositions. The 100-120 nm sized nanogels of fib-graft-PNVCL (LCST = 35 ?1 'C) was prepared using CaCl2 cross-linker. The 5-FU/Meg-fib-graft-PNVCL NGs showed a particle size of 150-170 nm size. The drug loading efficiency with 5-FU was 62% while Meg showed 74%. The 5-FU and Meg release was prominent above LCST than below LCST. The multi drug loaded fib-graft-PNVCL NGs showed enhanced toxicity, apoptosis and uptake by breast cancer (MCF-7) cells compared to their individual doses above their LCST. The in vivo assessment in Swiss albino mice showed sustained release of Meg and 5-FU as early as 3 days, confirming the therapeutic efficiency of the formulation. These results demonstrate an enhanced platform for the future animal studies on breast tumor xenograft model.

Periodontal Specific Differentiation of Dental Follicle Stem Cells into Osteoblast, Fibroblast, and Cementoblast.

The dental follicle is a source of dental follicle stem cells (DFCs), which have the potential to differentiate into the periodontal lineage. DFCs therefore are of value in dental tissue engineering. The purpose of this study was to evaluate the effect of growth factor type and concentration on DFC differentiation into periodontal specific lineages. DFCs were isolated from the human dental follicle and characterized for the expression of mesenchymal markers. The cells were positive for CD-73, CD-44, and CD-90; and negative for CD-33, CD-34, and CD-45. The expression of CD-29 and CD-31 was almost negligible. The cells also expressed periodontal ligament and cementum markers such as periodontal ligament-associated protein-1 (PLAP-1), fibroblast growth factor-2 (FGF-2), and cementum protein-1 (CEMP-1), however, the expression of osteoblast markers was absent. Further, the DFCs were cultured in three different induction medium to analyze the osteoblastic, fibroblastic, and cementoblastic differentiation. Runt-related transcription factor 2 (RUNX-2), alkaline phosphatase (ALP) activity, alizarin staining, calcium quantification, collagen type-1 (Col-1), and osteopontin (OPN) expression confirmed the osteoblastic differentiation of DFCs. DFCs cultured in recombinant human FGF-2 (rhFGF-2) containing medium showed enhanced PLAP-1, FGF-2, and COL-1 expression with increasing concentration of rhFGF-2 which thereby confirmed periodontal ligament fibroblastic differentiation. Similarly, DFCs cultured in recombinant human cementum protein-1 (rhCEMP-1) containing medium showed enhanced bone sialoprotein-2 (BSP-2), CEMP-1, and COL-1 expression with respect to rhCEMP-1 which confirmed cementoblastic differentiation. The expression of osteoblast, fibroblast, and cementoblast-related genes of DFCs cultured in induction medium was enhanced in comparison to DFCs cultured in noninduction medium. Thus, growth factor-dependent differentiation of DFCs into periodontal specific lineages was proved by quantitative analysis.

Injectable Chitin-Poly(ε-caprolactone)/Nanohydroxyapatite Composite Microgels Prepared by Simple Regeneration Technique for Bone Tissue Engineering.

Injectable gel systems, for the purpose of bone defect reconstruction, have many advantages, such as controlled flowability, adaptability to the defect site, and increased handling properties when compared to the conventionally used autologous graft, scaffolds, hydroxyapatite blocks, etc. In this work, nanohydroxyapatite (nHAp) incorporated chitin-poly(ε-caprolactone) (PCL) based injectable composite microgels has been developed by a simple regeneration technique for bone defect repair. The prepared microgel systems were characterized using scanning electron microscope (SEM), Fourier transformed infrared spectroscopy (FTIR), and X-ray diffraction (XRD). The composite microgel, with the incorporation of nHAp, showed an increased elastic modulus and thermal stability and had shear-thinning behavior proving the injectability of the system. The protein adsorption, cytocompatibility, and migration of rabbit adipose derived mesenchymal stem cells (rASCs) were also studied. Chitin-PCL-nHAp microgel elicited an early osteogenic differentiation compared to control gel. The immunofluorescence studies confirmed the elevated expression of osteogenic-specific markers such as alkaline phosphatase, osteopontin, and osteocalcin in chitin-PCL-nHAp microgels. Thus, chitin-PCL-nHAp microgel could be a promising injectable system for regeneration of bone defects which are, even in deeper planes, irregularly shaped and complex in nature.

Chitosan-hyaluronic acid/VEGF loaded fibrin nanoparticles composite sponges for enhancing angiogenesis in wounds.

Reduced levels of endogenous growth factors and diminished angiogenesis are contributory factors for impaired wound healing in diabetic patients. Vascular endothelial growth factor (VEGF) is the most potent angiogenic growth factor which stimulates multiple phases of wound healing angiogenesis and thereby accelerates healing. The aim of this work was to develop chitosan-hyaluronic acid composite sponge incorporated with fibrin nanoparticles loaded with VEGF as a wound dressing for diabetic wounds. VEGF loaded fibrin nanoparticles (150-180 nm) were prepared and characterized which were then incorporated to the composite sponge. The prepared sponges were characterized by SEM and FT-IR. Porosity, swelling, biodegradation, mechanical properties and haemostatic potential of the sponges were also studied. Release of VEGF from the composite sponges was evaluated using ELISA kit. More than 60% of the loaded VEGF was released in three days. Cell viability and attachment studies of the composite sponges were evaluated using human dermal fibroblast (HDF) cells and human umbilical vein endothelial cells (HUVECs). HUVECs seeded on VEGF containing sponges showed capillary like tube formation which was absent in control sponges. The results suggest that the prepared chitosan-hyaluronic acid/VEGF loaded nanofibrin composite sponges (CHVFS) have potential to induce angiogenesis in wound healing.