Neurodegenerative disorders management: state-of-art and prospects of nano-biotechnology.

Neurodegenerative disorders (NDs) are highly prevalent among the aging population. It affects primarily the central nervous system (CNS) but the effects are also observed in the peripheral nervous system. Neural degeneration is a progressive loss of structure and function of neurons, which may ultimately involve cell death. Such patients suffer from debilitating memory loss and altered motor coordination which bring up non-affordable and unavoidable socio-economic burdens. Due to the unavailability of specific therapeutics and diagnostics, the necessity to control or manage NDs raised the demand to investigate and develop efficient alternative approaches. Keeping trends and advancements in view, this report describes both state-of-the-art and challenges in nano-biotechnology-based approaches to manage NDs, toward personalized healthcare management. Sincere efforts are being made to customize nano-theragnostics to control: therapeutic cargo packaging, delivery to the brain, nanomedicine of higher efficacy, deep brain stimulation, implanted stimulation, and managing brain cell functioning. These advancements are useful to design future therapy based on the severity of the patient's neurodegenerative disease. However, we observe a lack of knowledge shared among scientists of a variety of expertise to explore this multi-disciplinary research field for NDs management. Consequently, this review will provide a guideline platform that will be useful in developing novel smart nano-therapies by considering the aspects and advantages of nano-biotechnology to manage NDs in a personalized manner. Nano-biotechnology-based approaches have been proposed as effective and affordable alternatives at the clinical level due to recent advancements in nanotechnology-assisted theragnostics, targeted delivery, higher efficacy, and minimal side effects.

Lignin: Drug/Gene Delivery and Tissue Engineering Applications.

Lignin is an abundant renewable natural biopolymer. Moreover, a significant development in lignin pretreatment and processing technologies has opened a new window to explore lignin and lignin-based bionanomaterials. In the last decade, lignin has been widely explored in different applications such as drug and gene delivery, tissue engineering, food science, water purification, biofuels, environmental, pharmaceuticals, nutraceutical, catalysis, and other interesting low-value-added energy applications. The complex nature and antioxidant, antimicrobial, and biocompatibility of lignin attracted its use in various biomedical applications because of ease of functionalization, availability of diverse functional sites, tunable physicochemical and mechanical properties. In addition to it, its diverse properties such as reactivity towards oxygen radical, metal chelation, renewable nature, biodegradability, favorable interaction with cells, nature to mimic the extracellular environment, and ease of nanoparticles preparation make it a very interesting material for biomedical use. Tremendous progress has been made in drug delivery and tissue engineering in recent years. However, still, it remains challenging to identify an ideal and compatible nanomaterial for biomedical applications. In this review, recent progress of lignin towards biomedical applications especially in drug delivery and in tissue engineering along with challenges, future possibilities have been comprehensively reviewed.

Synthesis and characterization of silver nanoparticles loaded poly(vinyl alcohol)-lignin electrospun nanofibers and their antimicrobial activity.

In the present study, poly(vinyl alcohol) (PVA) - Acacia lignin (PL) nanofiber mats loaded with silver nanoparticles were prepared and characterized. In-situ synthesis of silver nanoparticles was accomplished using alkali lignin extracted from Acacia wood as a reducing agent. Ultrafine nanofiber mats of PL incorporated with silver nanoparticles were fabricated using the electrospinning technique. The fiber morphology of the resultant nanofiber was characterized using scanning electron microscopy. The average diameter of the nanofiber was in the range of 100 to 300 nm. The existence of silver nanoparticles was confirmed by X-ray diffraction analysis. The influence of silver nanoparticles on the polymer structure was investigated by mechanical and thermal properties analysis. The antimicrobial activity of the PL nanofibers containing silver nanoparticles was tested against Bacillus circulans (MTCC 7906) and Escherichia coli (MTCC 739) and showed significant results against both microorganisms. The results revealed that PL nanofiber containing silver nanoparticles may have potential applications as membrane filtration, antimicrobial fabrics and wound dressing material.

Hydrogen peroxide sensing and cytotoxicity activity of Acacia lignin stabilized silver nanoparticles.

The study is aimed at detection of hydrogen peroxide (H2O2) using Acacia lignin mediated silver nanoparticles (AGNPs). The synthesis of AGNPs was achieved at conditions optimized as, 3 ml of 0.02% lignin and 1mM silver nitrate incubated for 30 min at 80°C and pH 9. Initial screening of AGNPs was performed by measuring the surface plasmon resonance peak at 410-430 nm using UV-vis spectrophotometer. Transmission electron microscopy, atomic force microscopy, X-ray diffraction and particle size analysis confirmed the spherical shaped face centered cubic structure and 10-50 nm size of AGNPs. The infrared spectroscopy study further revealed that the active functional groups present in lignin were responsible for the reduction of silver ions (Ag(+)) to metallic silver (Ag(0)). Lignin stabilized silver nanoparticles showed good sensitivity and a linear response over wide concentrations of H2O2 (10(-1) to 10(-6)M). Further, the in vitrocytotoxicity activity of the lignin mediated AGNPs (5-500 µg/ml) demonstrated toxicity effects in MCF-7 and A375 cell lines. Thus, lignin stabilized silver nanoparticles based optical sensor for H2O2 could be potentially applied in the determination of reactive oxygen species and toxic chemicals which further expands the importance of lignin stabilized silver nanoparticles.

In vitro antioxidant and antidiabetic activities of biomodified lignin from Acacia nilotica wood.

The antioxidant and antidiabetic activity of biomodified alkali lignin extracted from a deciduous plant Acacia nilotica, was evaluated in vitro. The extracted alkali lignin was subjected to microbial biotransformation by ligninolytic fungus Aspergillus flavus and Emericella nidulans. These modifications were done under varying concentration of carbon to nitrogen sources. The structural feature of the lignin samples were compared by FTIR, functional group analysis and (13)C solid state NMR. All lignin samples were tested for antioxidant efficiency, reducing power and H2O2 scavenging power. Modifications in all lignin samples showed correlation with their antioxidant scavenging activity and reducing power. Antidiabetic properties were evaluated in terms of in vitro glucose movement inhibition and α-amylase inhibition assay. Modified samples exhibited increased glucose binding efficiency as demonstrated by the decreased glucose diffusion (55.5-76.3%) and 1.16-1.18-fold enhanced α-amylase inhibition in comparison to their control samples. The results obtained demonstrate that the structure and functional modifications in lignin significantly affects its bioefficacy in term of antioxidant and antidiabetic activities.

Free radical scavenging activity and reducing power of Acacia nilotica wood lignin.

Nine different fractions of lignin extracted by alkali, hot water and organosolv methods from Acacia wood powder were assessed for antioxidants activity. Results indicated that methanolic lignin fraction had highest polyphenol content of 393.30±9.2µg/ml (GAE). The oraganosolv lignin with total phenols and phenolic hydroxyl group content exhibited significant antioxidant activity as compared to other lignin fractions. Antioxidant properties of acetone fractions revealed a high antiradical scavenging activity (<90%) with a simultaneous high ferric and molybdate ion reducing capacity. The influence of extraction methods on functional groups of lignin fractions was confirmed by analytical methods and Fourier transform infrared spectroscopy (FTIR) analysis. Whereas the phenolic content showed strong correlation with reducing capacity, the antiradical activity was moderately correlated with phenolic content. A high phenolic hydroxyl groups content of organosolv lignin fractions provides evidence for the presence of active therapeutic antioxidant compounds for their testing as potential value added products for cosmetics and pharmaceutical industries.