Neurodegenerative disorders: Mechanisms of degeneration and therapeutic approaches with their clinical relevance.

Neurodegenerative disorders (NDs) are expected to pose a significant challenge for both medicine and public health in the upcoming years due to global demographic changes. NDs are mainly represented by degeneration/loss of neurons, which is primarily accountable for severe mental illness. This neuronal degeneration leads to many neuropsychiatric problems and permanent disability in an individual. Moreover, the tight junction of the brain, blood-brain barrier (BBB)has a protective feature, functioning as a biological barrier that can prevent medicines, toxins, and foreign substances from entering the brain. However, delivering any medicinal agent to the brain in NDs (i.e., Multiple sclerosis, Alzheimer's, Parkinson's, etc.) is enormously challenging. There are many approved therapies to address NDs, but most of them only help treat the associated manifestations. The available therapies have failed to control the progression of NDs due to certain factors, i.e., BBB and drug-associated undesirable effects. NDs have extremely complex pathology, with many pathogenic mechanisms involved in the initiation and progression; thereby, a limited survival rate has been observed in ND patients. Hence, understanding the exact mechanism behind NDs is crucial to developing alternative approaches for improving ND patients' survival rates. Thus, the present review sheds light on different cellular mechanisms involved in NDs and novel therapeutic approaches with their clinical relevance, which will assist researchers in developing alternate strategies to address the limitations of conventional ND therapies. The current work offers the scope into the near future to improve the therapeutic approach of NDs.

Design of quetiapine fumarate loaded polyethylene glycol decorated graphene oxide nanosheets: Invitro-exvivo characterization.

Quetiapine Fumarate (QF) is an atypical antipsychotic with poor oral bioavailability (9%) due to its low permeability and pH-dependent solubility. Therefore, this study aims to design QF-loaded polyethylene glycol (PEG) functionalized graphene oxide nanosheets (GON) for nasal delivery of QF. In brief, GO was synthesized using a modified Hummers process, followed by ultra-sonication to produce GON. Subsequently, PEG-functionalized GON was prepared using carbodiimide chemistry (PEG-GON). QF was then decorated onto the cage of PEG-GON using the π-π stacking phenomenon (QF@PEG-GON). The QF@PEG-GON nanocomposite underwent several spectral characterizations, in vitro drug release, mucoadhesion study, ex vivo diffusion study, etc. The surface morphology of QF@PEG-GON nanocomposite validates the cracked nature of the nanocomposite, whereas the diffractograms and thermogram of nanocomposite confirm the conversion of QF into an amorphous form with uniform distribution in PEG-GON. Moreover, an ex vivo study of PEG-GON demonstrates superior mucoadhesion capacity due to its surface functional groups and hydrophilicity. The percent drug loading content and percent entrapment efficiency of the nanocomposite were found to be 9.2±0.62% and 92.3±1.02%, respectively. The developed nanocomposite exhibited 43.82±1.65% drug release within 24h, with the Korsemeyer-Peppas model providing the best-fit release kinetics (R2: 0.8614). Here, the interlayer spacing of PEG-GON prevented prompt diffusion of the buffer, leading to a delayed release pattern. In conclusion, the anticipated QF@PEG-GON nanocomposite shows promise as a nanocarrier platform for nasal delivery of QF.

Design of surface tailored carboxymethyl dextran-protein based nanoconjugates for paclitaxel: Spectroscopical characterizations and cytotoxicity assay.

Paclitaxel (PTX) is an essential anticancer drug from the biopharmaceutical classification system (BCS) class IV. Unfortunately, PTX has some drawbacks including low solubility, cell toxicity, adverse cell reaction, etc. Therefore, folic acid (FA) tailored carboxymethyl-dextran (CMD), and bovine serum albumin (BSA) mediated nanoconjugates of paclitaxel (PTX) (FA-CMD-BSA-PTX) were designed. At first, esterification reaction between FA and CMD resulted in FA-CMD conjugate whereas FA-CMD-BSA conjugate was synthesized via the Maillard reaction. Finally, FA-CMD-BSA conjugates of PTX were achieved via hydrophobic interaction and gelation of BSA. Herein, heating offers the gelation of BSA that furnishes the cross-linking wherein PTX gets fixed inside BSA. Thermogram of FA-CMD-BSA-PTX showed the absence of PTX peak that concluding PTX has been molecularly dispersed in polymer matrix and entrapment inside polymeric conjugate. As an effect, surface decorated FA-CMD-BSA-PTX showed low hemolytic toxicity over free PTX. Cytotoxicity assay on A549 human lung cancer cells shows cell viability decreased from 60 % to 10 % with increasing concentration from 1 to 5 µg/mL. In conclusion, CMD facilitates the circulation time of PTX and BSA acts as a carrier to target tumor locations effectively. The nano-conjugate formulation significantly reduces toxicity and can be used for the treatment of lung cancer.

Graphene quantum dots (GQDs) nanoarchitectonics for theranostic application in lung cancer.

Lung cancer (LC) is heading up as a substantial cause of mortality worldwide. Despite enormous progress in cancer management, LC remains a crucial problem for oncologists due to the lack of early diagnosis and precise treatment. In this context, numerous early diagnosis and treatment approaches for LC at the cellular level have been developed using advanced nanomaterials in the last decades. Amongst this, graphene quantum dots (GQDs) as a novel fluorescent material overwhelmed the horizons of materials science and biomedical fields due to their multifunctional attributes. Considering the complex nature of LC, emerging diagnostic and therapeutic (Theranostics) strategies using GQDs proved to be an effective way for the current practice in LC. In this line, we have abridged various approaches used in the LC theranostics using GQDs and its surface-engineered motif. The admirable photophysical attributes of GQDs realised in photolytic therapy (PLT), hyperthermia therapy (HTT), and drug delivery have been discussed. Furthermore, we have engrossed the impasse and its effects on the use of GQDs in cancer treatments from cellular level (in vivo-in vitro) to clinical. Inclusively, this review will be an embodiment for the scientific fraternity to design and magnify their view for the theranostic application of GQDs in LC treatment.

Affinity-Based Nanoarchitectured Biotransducer for Sensitivity Enhancement of Surface Plasmon Resonance Sensors for In Vitro Diagnosis: A Review.

Despite the indisputable benefits and advancement of science, technology, and civilization, early diagnosis of healthcare is still a challenging field for the scientific fraternity. The detection of biomarkers is a crucial attribute of prognosis and diagnosis of disease. Out of numerous techniques, surface plasmon resonance (SPR) bestows countless benefits, including in situ, label-free, and real-time assessment, etc., which authorizes the analysis of molecular binding occurrences between biotransducers and biomarkers. In addition, SPR with low-molecular-weight biomarkers lacks selectivity and sensitivity, which ultimately affects binding kinetics. This, in turn, leads to the remarkable development and implementation of numerous selectivity and sensitivity enhancement methods. Among the various noticeable strategies, because of selectivity and sensitivity enrichment substrate for SPR biosensors, affinity-based nanoarchitectured biotransducers stand out as being the best substitute. The present review elaborates significant advances made in the research based on affinity biotransducers for in vitro diagnosis using SPR biosensors for biomarker sensing. Moreover, most recent trends and challenges in designing and application of nanoarchitectured affinity biotransducer-based SPR biosensors for detecting low-concentration biomarkers have been reviewed comprehensively. This present review may assist the scientific fraternity in designing an ultramodern novel SPR approach based on affinity biotransducers, along with improved selectivity and sensitivity of SPR biosensors for in vitro and real-time diagnostic applications.

Recent Advancement in Bio-precursor derived graphene quantum dots: Synthesis, Characterization and Toxicological Perspective.

Graphene quantum dots (GQDs), impressive materials with enormous future potential, are reviewed from their inception, including different precursors. Considering the increasing burden of industrial and ecological bio-waste, there is an urgency to develop techniques which will convert biowaste into active moieties of interest. Amongst the various materials explored, we selectively highlight the use of potential carbon containing bioprecursors (e.g. plant-based, amino acids, carbohydrates), and industrial waste and its conversion into GQDs with negligible use of chemicals. This review focuses on the effects of different processing parameters that affect the properties of GQDs, including the surface functionalization, paradigmatic characterization, toxicity and biocompatibility issues of bioprecursor derived GQDs. This review also examines current challenges and s the ongoing exploration of potential bioprecursors for ecofriendly GQD synthesis for future applications. This review sheds further light on the electronic and optical properties of GQDs along with the effects of doping on the same. This review may aid in future design approaches and applications of GQDs in the biomedical and materials design fields.

Graphene-based nanocomposites for sensitivity enhancement of surface plasmon resonance sensor for biological and chemical sensing: A review.

Surface plasmon resonance (SPR) offers exceptional advantages such as label-free, in-situ and real-time measurement ability that facilitates the study of molecular or chemical binding events. Besides, SPR lacks in the detection of various binding events, particularly involving low molecular weight molecules. This drawback ultimately resulted in the development of several sensitivity enhancement methodologies and their application in the various area. Among graphene materials, graphene-based nanocomposites stands out owing to its significant properties such as strong adsorption of molecules, signal amplification by optical, high carrier mobility, electronic bridging, ease of fabrication and therefore, have established as an important sensitivity enhancement substrate for SPR. Also, graphene-based nanocomposites could amplify the signal generated by plasmon material and increase the sensitivity of molecular detection up to femto to atto molar level. This review focuses on the current important developments made in the potential research avenue of SPR and fiber optics based SPR for chemical and biological sensing. Latest trends and challenges in engineering and applications of graphene-based nanocomposites enhanced sensors for detecting minute and low concentration biological and chemical analytes are reviewed comprehensively. This review may aid in futuristic designing approaches and application of grapheneous sensor platforms for sensitive plasmonic nano-sensors.