Fabrication of β-cyclodextrin and sialic acid copolymer by single pot reaction to site specific drug delivery

Chitosan-grafted folic acid decorated one-dimensional GONS: A biocompatible drug cargo for targeted co-delivery of anticancer agents

In conventional chemotherapy, the cancer cells can become highly resilient due to a phenomenon known as multi-drug resistance (MDR). The co-delivery of chemotherapeutic agents assisted with novel nanocarrier-based targeted DDS may counter the MDR issues and subsequently improve their therapeutic efficacy. In line with this, the present work deals with the development of 1D graphene oxide nanoscrolls (GONS)-based nano delivery system for co-delivery of chemosensitizer along with the chemotherapeutic agent. Herein, the 1D GONS nanocarrier was initially functionalized with chitosan (CS) biopolymer and folic acid (FA) further to enhance their biocompatibility and target-specific co-delivery. The resultant GONS-CS-FA (GCF) nanocarriers were co-loaded with doxorubicin (DOX) and caffeic acid (CA) at different weight proportions with respect to nanocarrier and drug composition. The optimum loading efficiency of 51.14 ± 1.47 % (DOX) and 49.70 ± 1.19 % (CA) was observed for GCF: drug ratio of 2.5 with drug composition of 1:1. In vitro release at pH 5 yielded ~83 % DOX and 75 % CA, compared to ~71 % DOX and 61 % CA at pH 7.4 over 7 days, suggesting a higher and targeted drug release in the cancer microenvironment. Cytotoxicity tests revealed selective apoptosis in cancer cells (A549) while maintaining cytocompatibility with normal cells (HEK293).

Development and evaluation of multi-functionalized sialic acid conjugated asiatic acid nanoconstruct to mitigate cognitive deficits in Alzheimer's disease

Sialic acid (SA) serves a critical role in neuronal repair and cognitive functions. SA is a nine-carbon carboxylated sugar with a glycoconjugate cap that acts as a ligand and surface decoration with SA facilitates delivery to the target site. The present research aimed to develop SA surface modified AA nanostructured lipid carrier (NLCs) with carbodiimide conjugation method. Sterylamine, poloxamer 188 and tween 80 were used as surfactants and several characterization studies including, differential scanning calorimetry, fourier transform infrared spectroscopy and x-ray photon spectroscopy were analyzed. Further, in vitro, neuroprotective efficiency was evaluated in SH-SY5Y cells and hCMEC/D3 cells and found significant potential effects with the treatments of developed NLCs. Pharmacodynamics studies were also assessed in beta-amyloid-injected rats following quantification of Alzheimer's disease (AD) hallmarks like, Aβ(1-42), tau-protein, glycogen synthase kinase-3β levels, interleukin-6 and tumor necrosis factor-α for neuroinflammatory responses. Characterization studies revealed the conjugation on developed NLCs. The in vitro and in vivo results showed significant effects of SA decorated NLCs in reversing the damage by toxicant which was further characterized by the levels of neurotransmitters like acetylcholinesterase, butyrylcholinesterase. The results revealed significant (p < .05) refurbishment of cholinergic functions after 28 days of treatment of developed NLCs. These preclinical findings support the use of SA as a ligand to deliver the AA at targeted site as well as to mitigate the cognitive deficits in AD.

Novel mono- and multivalent N-acetylneuraminic acid glycoclusters as potential broad-spectrum entry inhibitors for influenza and coronavirus infection

N-acetylneuraminic acid (Neu5Ac) is a glycan receptor of viruses spread in many eukaryotic cells. The present work aimed to design, synthesis and biological evaluation of a panel of Neu5Ac derivatives based on a cyclodextrin (CD) scaffold for targeting influenza and coronavirus membrane proteins. The multivalent Neu5Ac glycoclusters efficiently inhibited chicken erythrocyte agglutination induced by intact influenza virus in a Neu5Ac density-dependent fashion. Compared with inhibition by Neu5Ac, the multivalent inhibitor with 21 Neu5Ac residues on the primary face of the β-CD scaffold afforded 1788-fold higher binding affinity inhibition for influenza virus hemagglutinin with a dissociation constant (KD) of 3.87 × 10-7 M. It showed moderate binding affinity to influenza virus neuraminidase, but with only about one-thirtieth the potency of that with the HA protein. It also exhibited strong binding affinity to the spike protein of three human coronaviruses (severe acute respiratory syndrome coronavirus, Middle East respiratory syndrome coronavirus, and severe acute respiratory syndrome coronavirus 2), with KD values in the low micromolar range, which is about 10-time weaker than that of HA. Therefore, these multivalent sialylated CD derivatives have possible therapeutic application as broad-spectrum antiviral entry inhibitors for many viruses by targeting the Neu5Ac of host cells.

3D direct printing of composite bone scaffolds containing polylactic acid and spray dried mesoporous bioactive glass-ceramic microparticles

In this study, a three-dimensional composite scaffold is proposed consisting of polylactic acid and spray dried glass-ceramic microparticles (SGCMs). The compositional and structural characterization showed that the obtained spray dried powder formed as glass-ceramic (GC) with a completely interconnected porosity structure. Before direct printing of scaffolds, the rheological behavior of polylactic acid (PLA) and PLA-GC (PLA matrix containing SGCMs) inks were investigated. The PLA-GC composite ink represents sharper shear-thinning behavior and higher loss and storage modulus comparable to that of pure PLA. Microscopic observations and elemental mapping elements showed that 3D scaffolds had well-defined interconnected porosity and uniform distribution of the glass-ceramic particles. Mechanical tests indicated that compression strength is dependent on the scaffold porosity and the presence of SGCMs. Apatite formation evaluation besides ion release study showed better biomineralization capacity of PLA-GC scaffolds, as larger and denser sediments formed on the PLA-GC scaffolds after 7- and 14-day soaking. The preliminary cell response was studied with primary human mesenchymal stem cells (hMSCs) and revealed that SGCMs improved cell adhesion and viability and ALP activity. The appropriate combination of the biomaterials/methods to fabricate 3D porous constructs and their available bioactivity and biocompatibility, both being important characteristics for bone tissue engineering applications.

Selective point-of-care detection of pathogenic bacteria using sialic acid functionalized gold nanoparticles

In resource-limited settings, fast and simple point-of-need tests should facilitate healthcare providers the identification of pathogens avoiding empirical suboptimal treatments with broad-spectrum antibiotics. A rapid optical whole cell bacterial biosensor has been here developed using sialic acid functionalized gold nanoparticles allowing the selective screening of Gram-positive Staphylococcus aureus ATCC 25923 and Methicillin Resistant Staphylococcus aureus (MRSA) USA300 and Gram-negative bacteria (Pseudomonas aeruginosa ATCC 15442) by selecting the appropriate dispersing media. Those bacteria were selected due to their common presence in wound bed tissue of chronic infected topical wounds. The discrimination of bacterial pathogens has been attempted in different media including water, two independent buffers, bacterial broth, human serum and human urine. The identification of Gram + bacterial pathogens was also assessed under simultaneous co-culture of S. Aureus and Pseudomonas aeruginosa. High bacterial loads were required to provide with a statistically significant optical pathogen identification in human serum whereas it was not possible to detect the presence of bacteria at clinically relevant levels in urine.

Iron-caseinglycomacropeptide complexes: Characterization and application in beverages

Complexing iron with organic compounds has been considered an alternative strategy to mitigate the problems associated with the level of bioavailable iron and the acceptability of products supplemented with this mineral. CMP contains specific amino acids associated with iron binding. The present study aims to optimize the conditions of Fe/CMP complex formation and understand the molecular basis of interactions between CMP and iron ions. Results showed that CMP can bind ferrous iron in a 1:1.5 M ratio, forming a stable peptide-iron complex, where CMP assembles in a tetrameric form. FTIR spectra indicated that iron binding altered the secondary structures of CMP. The iron-binding sites of CMP corresponded primarily to acid residues of Glu, Asp and sialic acid. Moreover, Fe/CMP complex remained stable in a wide pH range (2.0-6.5), suggesting the adequacy to be efficiently added in food or beverages and to keeping complexed in the digestion environment. Finally, Fe/CMP complex was added to a commercial beverage (2 mg of Fe per serving of beverage) and no changes were observed in their colour during storage. A model to explain the binding between CMP and iron is proposed. These results suggest a potential application of this peptide for iron fortification.

Hyaluronic-acid-based β-cyclodextrin grafted copolymers as biocompatible supramolecular hosts to enhance the water solubility of tocopherol

Hyaluronic acid (HA), a common biopolymer found in the extracellular fluid, was grafted with β-cyclodextrin (β-CD) to form a composite polymer that could form inclusion complexes with tocopherol (VE), enhancing its water-solubility and serving as a model drug delivery system. Herein, different copolymers were prepared with varying HA:β-CD ratios and characterized. VE loading capacity was directly correlated with increased β-CD composition in the polymers and morphological changes were observed upon VE binding. The host materials and their VE inclusion complexes are not cytotoxic, and are thus useful for VE and drug delivery.

Cyclodextrin Based Nanoparticles for Drug Delivery and Theranostics

Colloidal nanoparticulate technology has been described in the literature as a versatile drug delivery system. But it possesses some inherent lacunae in their formulation. Cyclodextrins (CDs) have been extensively reported for the solubility enhancement of poorly water-soluble drugs. The CDs can cause intervention in aspects related to nanoparticles (NPs) that include improving drug loading in nano-system, improving stability, site-specific/targeted drug delivery, improving solubility profile and absorption of the drug in nanosystem with consequent improvement in bioavailability, with the possibility of controlled release, safety and efficacy. They find application in for simultaneous diagnosis and therapeutics for better treatment procedures. The current communication is focused on the application of CDs to overcome troubles in nanoparticulate formulation and enhancement of their performance. It also envisages the theranostic aspects of CDs.