Polylactic acid nanocomposites containing functionalized multiwalled carbon nanotubes as antimicrobial packaging materials.

Intended for food packaging, nanocomposites films based on poly (lactic acid) reinforced by polydopamine-wrapped carbon nanotubes (PLA/PDA-MWCNTs) or TiO2 modified PDA-MWCNTs (PLA/TiO2-PDA-MWCNTs) as nanofillers were elaborated via melt-blending and characterized by several techniques. The success of the synthesis of the modified MWCNTs was confirmed by transmission electron microscopy, Raman and Fourier transform infrared spectroscopies and thermogravimetric analysis. Properties such as slow crystallization rate, barrier, mechanical, antibacterial and antifungal properties, required for food packaging, have been investigated. As compared to a PLA pristine film, the PLA based modified MWCNTs at 3 wt% loading exhibited better properties, particularly the PLA/TiO2-PDA-MWCNTs nanocomposite film. Indeed, the crystallization rate increased about 10% for PLA/TiO2-PDA-MWCNTs and 7% for PLA/PDA-MWCNTs compared to the neat PLA. Besides, these improved results have positively impacted on the nanomechanical and barrier properties of PLA nanocomposites films. The Young modulus was increased by 161% for PLA/TiO2-PDA-MWCNTs and 113% for PLA/PDA-MWCNTs and the hardness was improved by 815% for PLA/TiO2-PDA-MWCNTs and 79% for PLA/PDA-MWCNTs, respectively, as compared to the pristine PLA. Furthermore, PLA based modified MWCNTs nanocomposite films displayed a strong antimicrobial and antifungal activity compared to pure PLA.

Gold modified polydopamine coated mesoporous silica nano-structures for synergetic chemo-photothermal effect.

Near infrared (NIR) responsive agents have attracted a great attention in nanomedicine due to their efficient photothermal effect (PTE) and eco-friendly nature. In our study, a novel kind of nanostructure were developed based on mesoporous silica nanoparticles (MSN) loaded doxorubicin(DOX) core and polydopamine-gold nanoparticles shell (PDA-AuNPs), the system was designed for combined chemo and photothermal therapy into one system. The designed nanostructure were thoroughly characterized to confirm their structure and to ensure their efficiency as cargo delivery system (DDS). The pH controlled release behavior of DOX from the designed nanostructures was investigated, approximately 60% of DOX was released over 48 h. Under NIR irradiation, the nanoparticles exhibited good photothermal stability and a high photothermal conversion efficiency of approximately 49%. Importantly, the MSN@DOX-PDA-AuNPs nanostructures showed a synergetic photo and chemotherapeutic effect, with the enhanced DOX release by 19% over 15 h and 15.42% over 250 min with 4 cycles of NIR laser irradiation. The combined chemo-photothermal in an acidic environment and under NIR irradiation was successfully proved.

Synthesis and evaluation of water soluble pH sensitive poly (vinyl alcohol)-doxorubicin conjugates.

The accuracy of spatiotemporal control cargo delivery and release are primordial to enhance the therapeutic efficiency and decrease the undesirable effects, in this context a novel prodrug were developed based on biocompatible polyvinyl alcohol (PVA) substrate. PVA was conjugated to doxorubicin (PVA-DOX) via an acid-labile hydrazone linkage. PVA was first functionalized with acidic groups, then reacted with hydrazine hydrate to form an amide bond. The amine group of PVA hydrazide was linked to carbonyl group (C = O) of DOX to form a pH sensitive hydrazone bond. The molecular structure of the PVA-DOX was confirmed by FTIR, XPS, and 1H-NMR analysis methods. The degree of grafting were evaluated by TGA and confirmed by XPS, which reveals the successful bond attachment of DOX to PVA. Our findings confirm pH dependent DOX release from PVA-DOX prodrug with faster release rate in acidic environment (pH 5.0, pH 6.0) and slower release rate in neutral pH environment (pH 7.4). Compared to the primary DOX, our synthesized PVA-DOX conjugates could exhibit a promising therapeutic effect, high biocompatibility and zero premature release. The results prove the successful synthesis of PVA-DOX conjugates with high efficiency.

Functional polymer materials affecting cell attachment.

This review discusses the functional polymer materials effect on the cell adhesion. The applied polymer materials for the cell adhesion purpose was prepared based on organic fibers and biocompatible hydrogel. On the other hand, the active peptides are incorporated into the polymer materials substrate via the cysteine-containing peptides and N-hydroxysuccinimide-active group. Cancer cells and normal cells were presented for the selective adhesion via the introduced polymer materials substrate containing active peptides including Arginine-Glycine-Aspartic and Isoleucine-Lysine-Valine-Alanine-Valine sequence peptides. This selectivity is revealed by a significant cooperativity between specific and non-specific cell adhesion. This study is of a great impact for the design of the polymeric structures for cell attachment.

Spatio-temporal control strategy of drug delivery systems based nano structures.

The drug instability, toxicity and the barrier to the target area necessitate a suitable drug delivery system with an external or internal control of the release. Spatio-temporal control using a surface functionalized nano-carrier seems to be the best alternative for guided drug delivery and release. This manuscript provides a broad spectrum about the drug carrier interface modification to cover the need for temporal drug delivery control under neglect side effects. On the other hand, recent advances related to the drug vehicle are highlighted, besides physical (Electric field, magnetic field, light) or mechanical (Ultrasound, mechanical strain), chemical (pH, redox gradient, enzyme) stimuli mediated DDS. Precisely, the paper focus on the NIR light as an effective external stimulus for remotely-triggered DDS. NIR responsive drug delivery systems are considered as novel drug modality that ensures an eco-friendly spatiotemporal control and an administrated meditation. This study also investigated the NIIR spectroscopy (NIRS) combined with partial least square (PLS) for quantitative analysis of a polyvinyl alcohol based prodrug (PVA-DOX) in order to reveal the high potential of NIRS for drug release monitoring and the extraction of concise calibration models.

An Investigation of the High Performance of a Novel Type of Benzobisoxazole Fiber Based on 3,3-Diaminobenzidine.

The mechanical and thermal properties of poly{2,6-diimidazo[4,5-b:4'5'-e] pyridinylene-1,4(2,5-dihydroxy) phenylene} (PIPD)-3,3-diaminobenzidine (DAB) fibers were analyzed. Compared to other types of benzimidazole fiber structures and properties, PIPD-DAB is distinguished by a unique combination of strength, tensile modulus, and thermal properties. The PIPD polymer was prepared from 2,3,5,6-tetra-aminopyridine (TAP) and 2,5-dihydroxyterephthalic acid (DHTA) in polyphosphoric acid (PPA). In order to enhance the tensile strength and modulus, a third comonomer, 3,3-diaminobenzidine (DAB), was incorporated into the PIPD molecular structure. The change in molecular structure was recorded using Fourier-transform infrared (FT-IR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, and wide angle X-ray diffraction (WAXD). Compared to the PIPD fibers (average tensile strength of PIPD is 3.9 GPa, average tensile modulus of PIPD is 287 GPa), the tensile strength and modulus of PIPD-DAB increased to 4.2 and 318 GPa, respectively. In addition, the thermal decomposition temperature of the PIPD fibers is enhanced by 35 °C, due to the incorporated DAB. PIPD-DAB is a promising material for use under high tensile loads and/or high temperatures.